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1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3    Copyright (C) 2002 Richard Henderson
4    Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
5 
6 */
7 
8 #define INCLUDE_VERMAGIC
9 
10 #include <linux/export.h>
11 #include <linux/extable.h>
12 #include <linux/moduleloader.h>
13 #include <linux/module_signature.h>
14 #include <linux/trace_events.h>
15 #include <linux/init.h>
16 #include <linux/kallsyms.h>
17 #include <linux/file.h>
18 #include <linux/fs.h>
19 #include <linux/sysfs.h>
20 #include <linux/kernel.h>
21 #include <linux/kernel_read_file.h>
22 #include <linux/slab.h>
23 #include <linux/vmalloc.h>
24 #include <linux/elf.h>
25 #include <linux/proc_fs.h>
26 #include <linux/security.h>
27 #include <linux/seq_file.h>
28 #include <linux/syscalls.h>
29 #include <linux/fcntl.h>
30 #include <linux/rcupdate.h>
31 #include <linux/capability.h>
32 #include <linux/cpu.h>
33 #include <linux/moduleparam.h>
34 #include <linux/errno.h>
35 #include <linux/err.h>
36 #include <linux/vermagic.h>
37 #include <linux/notifier.h>
38 #include <linux/sched.h>
39 #include <linux/device.h>
40 #include <linux/string.h>
41 #include <linux/mutex.h>
42 #include <linux/rculist.h>
43 #include <linux/uaccess.h>
44 #include <asm/cacheflush.h>
45 #include <linux/set_memory.h>
46 #include <asm/mmu_context.h>
47 #include <linux/license.h>
48 #include <asm/sections.h>
49 #include <linux/tracepoint.h>
50 #include <linux/ftrace.h>
51 #include <linux/livepatch.h>
52 #include <linux/async.h>
53 #include <linux/percpu.h>
54 #include <linux/kmemleak.h>
55 #include <linux/jump_label.h>
56 #include <linux/pfn.h>
57 #include <linux/bsearch.h>
58 #include <linux/dynamic_debug.h>
59 #include <linux/audit.h>
60 #include <uapi/linux/module.h>
61 #include "module-internal.h"
62 
63 #define CREATE_TRACE_POINTS
64 #include <trace/events/module.h>
65 
66 #ifndef ARCH_SHF_SMALL
67 #define ARCH_SHF_SMALL 0
68 #endif
69 
70 /*
71  * Modules' sections will be aligned on page boundaries
72  * to ensure complete separation of code and data, but
73  * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y
74  */
75 #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
76 # define debug_align(X) ALIGN(X, PAGE_SIZE)
77 #else
78 # define debug_align(X) (X)
79 #endif
80 
81 /* If this is set, the section belongs in the init part of the module */
82 #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
83 
84 /*
85  * Mutex protects:
86  * 1) List of modules (also safely readable with preempt_disable),
87  * 2) module_use links,
88  * 3) module_addr_min/module_addr_max.
89  * (delete and add uses RCU list operations). */
90 DEFINE_MUTEX(module_mutex);
91 EXPORT_SYMBOL_GPL(module_mutex);
92 static LIST_HEAD(modules);
93 
94 /* Work queue for freeing init sections in success case */
95 static void do_free_init(struct work_struct *w);
96 static DECLARE_WORK(init_free_wq, do_free_init);
97 static LLIST_HEAD(init_free_list);
98 
99 #ifdef CONFIG_MODULES_TREE_LOOKUP
100 
101 /*
102  * Use a latched RB-tree for __module_address(); this allows us to use
103  * RCU-sched lookups of the address from any context.
104  *
105  * This is conditional on PERF_EVENTS || TRACING because those can really hit
106  * __module_address() hard by doing a lot of stack unwinding; potentially from
107  * NMI context.
108  */
109 
__mod_tree_val(struct latch_tree_node * n)110 static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
111 {
112 	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
113 
114 	return (unsigned long)layout->base;
115 }
116 
__mod_tree_size(struct latch_tree_node * n)117 static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
118 {
119 	struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
120 
121 	return (unsigned long)layout->size;
122 }
123 
124 static __always_inline bool
mod_tree_less(struct latch_tree_node * a,struct latch_tree_node * b)125 mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
126 {
127 	return __mod_tree_val(a) < __mod_tree_val(b);
128 }
129 
130 static __always_inline int
mod_tree_comp(void * key,struct latch_tree_node * n)131 mod_tree_comp(void *key, struct latch_tree_node *n)
132 {
133 	unsigned long val = (unsigned long)key;
134 	unsigned long start, end;
135 
136 	start = __mod_tree_val(n);
137 	if (val < start)
138 		return -1;
139 
140 	end = start + __mod_tree_size(n);
141 	if (val >= end)
142 		return 1;
143 
144 	return 0;
145 }
146 
147 static const struct latch_tree_ops mod_tree_ops = {
148 	.less = mod_tree_less,
149 	.comp = mod_tree_comp,
150 };
151 
152 static struct mod_tree_root {
153 	struct latch_tree_root root;
154 	unsigned long addr_min;
155 	unsigned long addr_max;
156 } mod_tree __cacheline_aligned = {
157 	.addr_min = -1UL,
158 };
159 
160 #define module_addr_min mod_tree.addr_min
161 #define module_addr_max mod_tree.addr_max
162 
__mod_tree_insert(struct mod_tree_node * node)163 static noinline void __mod_tree_insert(struct mod_tree_node *node)
164 {
165 	latch_tree_insert(&node->node, &mod_tree.root, &mod_tree_ops);
166 }
167 
__mod_tree_remove(struct mod_tree_node * node)168 static void __mod_tree_remove(struct mod_tree_node *node)
169 {
170 	latch_tree_erase(&node->node, &mod_tree.root, &mod_tree_ops);
171 }
172 
173 /*
174  * These modifications: insert, remove_init and remove; are serialized by the
175  * module_mutex.
176  */
mod_tree_insert(struct module * mod)177 static void mod_tree_insert(struct module *mod)
178 {
179 	mod->core_layout.mtn.mod = mod;
180 	mod->init_layout.mtn.mod = mod;
181 
182 	__mod_tree_insert(&mod->core_layout.mtn);
183 	if (mod->init_layout.size)
184 		__mod_tree_insert(&mod->init_layout.mtn);
185 }
186 
mod_tree_remove_init(struct module * mod)187 static void mod_tree_remove_init(struct module *mod)
188 {
189 	if (mod->init_layout.size)
190 		__mod_tree_remove(&mod->init_layout.mtn);
191 }
192 
mod_tree_remove(struct module * mod)193 static void mod_tree_remove(struct module *mod)
194 {
195 	__mod_tree_remove(&mod->core_layout.mtn);
196 	mod_tree_remove_init(mod);
197 }
198 
mod_find(unsigned long addr)199 static struct module *mod_find(unsigned long addr)
200 {
201 	struct latch_tree_node *ltn;
202 
203 	ltn = latch_tree_find((void *)addr, &mod_tree.root, &mod_tree_ops);
204 	if (!ltn)
205 		return NULL;
206 
207 	return container_of(ltn, struct mod_tree_node, node)->mod;
208 }
209 
210 #else /* MODULES_TREE_LOOKUP */
211 
212 static unsigned long module_addr_min = -1UL, module_addr_max = 0;
213 
mod_tree_insert(struct module * mod)214 static void mod_tree_insert(struct module *mod) { }
mod_tree_remove_init(struct module * mod)215 static void mod_tree_remove_init(struct module *mod) { }
mod_tree_remove(struct module * mod)216 static void mod_tree_remove(struct module *mod) { }
217 
mod_find(unsigned long addr)218 static struct module *mod_find(unsigned long addr)
219 {
220 	struct module *mod;
221 
222 	list_for_each_entry_rcu(mod, &modules, list,
223 				lockdep_is_held(&module_mutex)) {
224 		if (within_module(addr, mod))
225 			return mod;
226 	}
227 
228 	return NULL;
229 }
230 
231 #endif /* MODULES_TREE_LOOKUP */
232 
233 /*
234  * Bounds of module text, for speeding up __module_address.
235  * Protected by module_mutex.
236  */
__mod_update_bounds(void * base,unsigned int size)237 static void __mod_update_bounds(void *base, unsigned int size)
238 {
239 	unsigned long min = (unsigned long)base;
240 	unsigned long max = min + size;
241 
242 	if (min < module_addr_min)
243 		module_addr_min = min;
244 	if (max > module_addr_max)
245 		module_addr_max = max;
246 }
247 
mod_update_bounds(struct module * mod)248 static void mod_update_bounds(struct module *mod)
249 {
250 	__mod_update_bounds(mod->core_layout.base, mod->core_layout.size);
251 	if (mod->init_layout.size)
252 		__mod_update_bounds(mod->init_layout.base, mod->init_layout.size);
253 }
254 
255 #ifdef CONFIG_KGDB_KDB
256 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
257 #endif /* CONFIG_KGDB_KDB */
258 
module_assert_mutex(void)259 static void module_assert_mutex(void)
260 {
261 	lockdep_assert_held(&module_mutex);
262 }
263 
module_assert_mutex_or_preempt(void)264 static void module_assert_mutex_or_preempt(void)
265 {
266 #ifdef CONFIG_LOCKDEP
267 	if (unlikely(!debug_locks))
268 		return;
269 
270 	WARN_ON_ONCE(!rcu_read_lock_sched_held() &&
271 		!lockdep_is_held(&module_mutex));
272 #endif
273 }
274 
275 #ifdef CONFIG_MODULE_SIG
276 static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
277 module_param(sig_enforce, bool_enable_only, 0644);
278 
set_module_sig_enforced(void)279 void set_module_sig_enforced(void)
280 {
281 	sig_enforce = true;
282 }
283 #else
284 #define sig_enforce false
285 #endif
286 
287 /*
288  * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
289  * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
290  */
is_module_sig_enforced(void)291 bool is_module_sig_enforced(void)
292 {
293 	return sig_enforce;
294 }
295 EXPORT_SYMBOL(is_module_sig_enforced);
296 
297 /* Block module loading/unloading? */
298 int modules_disabled = 0;
299 core_param(nomodule, modules_disabled, bint, 0);
300 
301 /* Waiting for a module to finish initializing? */
302 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
303 
304 static BLOCKING_NOTIFIER_HEAD(module_notify_list);
305 
register_module_notifier(struct notifier_block * nb)306 int register_module_notifier(struct notifier_block *nb)
307 {
308 	return blocking_notifier_chain_register(&module_notify_list, nb);
309 }
310 EXPORT_SYMBOL(register_module_notifier);
311 
unregister_module_notifier(struct notifier_block * nb)312 int unregister_module_notifier(struct notifier_block *nb)
313 {
314 	return blocking_notifier_chain_unregister(&module_notify_list, nb);
315 }
316 EXPORT_SYMBOL(unregister_module_notifier);
317 
318 /*
319  * We require a truly strong try_module_get(): 0 means success.
320  * Otherwise an error is returned due to ongoing or failed
321  * initialization etc.
322  */
strong_try_module_get(struct module * mod)323 static inline int strong_try_module_get(struct module *mod)
324 {
325 	BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
326 	if (mod && mod->state == MODULE_STATE_COMING)
327 		return -EBUSY;
328 	if (try_module_get(mod))
329 		return 0;
330 	else
331 		return -ENOENT;
332 }
333 
add_taint_module(struct module * mod,unsigned flag,enum lockdep_ok lockdep_ok)334 static inline void add_taint_module(struct module *mod, unsigned flag,
335 				    enum lockdep_ok lockdep_ok)
336 {
337 	add_taint(flag, lockdep_ok);
338 	set_bit(flag, &mod->taints);
339 }
340 
341 /*
342  * A thread that wants to hold a reference to a module only while it
343  * is running can call this to safely exit.  nfsd and lockd use this.
344  */
__module_put_and_exit(struct module * mod,long code)345 void __noreturn __module_put_and_exit(struct module *mod, long code)
346 {
347 	module_put(mod);
348 	do_exit(code);
349 }
350 EXPORT_SYMBOL(__module_put_and_exit);
351 
352 /* Find a module section: 0 means not found. */
find_sec(const struct load_info * info,const char * name)353 static unsigned int find_sec(const struct load_info *info, const char *name)
354 {
355 	unsigned int i;
356 
357 	for (i = 1; i < info->hdr->e_shnum; i++) {
358 		Elf_Shdr *shdr = &info->sechdrs[i];
359 		/* Alloc bit cleared means "ignore it." */
360 		if ((shdr->sh_flags & SHF_ALLOC)
361 		    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
362 			return i;
363 	}
364 	return 0;
365 }
366 
367 /* Find a module section, or NULL. */
section_addr(const struct load_info * info,const char * name)368 static void *section_addr(const struct load_info *info, const char *name)
369 {
370 	/* Section 0 has sh_addr 0. */
371 	return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
372 }
373 
374 /* Find a module section, or NULL.  Fill in number of "objects" in section. */
section_objs(const struct load_info * info,const char * name,size_t object_size,unsigned int * num)375 static void *section_objs(const struct load_info *info,
376 			  const char *name,
377 			  size_t object_size,
378 			  unsigned int *num)
379 {
380 	unsigned int sec = find_sec(info, name);
381 
382 	/* Section 0 has sh_addr 0 and sh_size 0. */
383 	*num = info->sechdrs[sec].sh_size / object_size;
384 	return (void *)info->sechdrs[sec].sh_addr;
385 }
386 
387 /* Provided by the linker */
388 extern const struct kernel_symbol __start___ksymtab[];
389 extern const struct kernel_symbol __stop___ksymtab[];
390 extern const struct kernel_symbol __start___ksymtab_gpl[];
391 extern const struct kernel_symbol __stop___ksymtab_gpl[];
392 extern const struct kernel_symbol __start___ksymtab_gpl_future[];
393 extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
394 extern const s32 __start___kcrctab[];
395 extern const s32 __start___kcrctab_gpl[];
396 extern const s32 __start___kcrctab_gpl_future[];
397 #ifdef CONFIG_UNUSED_SYMBOLS
398 extern const struct kernel_symbol __start___ksymtab_unused[];
399 extern const struct kernel_symbol __stop___ksymtab_unused[];
400 extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
401 extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
402 extern const s32 __start___kcrctab_unused[];
403 extern const s32 __start___kcrctab_unused_gpl[];
404 #endif
405 
406 #ifndef CONFIG_MODVERSIONS
407 #define symversion(base, idx) NULL
408 #else
409 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
410 #endif
411 
each_symbol_in_section(const struct symsearch * arr,unsigned int arrsize,struct module * owner,bool (* fn)(const struct symsearch * syms,struct module * owner,void * data),void * data)412 static bool each_symbol_in_section(const struct symsearch *arr,
413 				   unsigned int arrsize,
414 				   struct module *owner,
415 				   bool (*fn)(const struct symsearch *syms,
416 					      struct module *owner,
417 					      void *data),
418 				   void *data)
419 {
420 	unsigned int j;
421 
422 	for (j = 0; j < arrsize; j++) {
423 		if (fn(&arr[j], owner, data))
424 			return true;
425 	}
426 
427 	return false;
428 }
429 
430 /* Returns true as soon as fn returns true, otherwise false. */
each_symbol_section(bool (* fn)(const struct symsearch * arr,struct module * owner,void * data),void * data)431 static bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
432 				    struct module *owner,
433 				    void *data),
434 			 void *data)
435 {
436 	struct module *mod;
437 	static const struct symsearch arr[] = {
438 		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
439 		  NOT_GPL_ONLY, false },
440 		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
441 		  __start___kcrctab_gpl,
442 		  GPL_ONLY, false },
443 		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
444 		  __start___kcrctab_gpl_future,
445 		  WILL_BE_GPL_ONLY, false },
446 #ifdef CONFIG_UNUSED_SYMBOLS
447 		{ __start___ksymtab_unused, __stop___ksymtab_unused,
448 		  __start___kcrctab_unused,
449 		  NOT_GPL_ONLY, true },
450 		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
451 		  __start___kcrctab_unused_gpl,
452 		  GPL_ONLY, true },
453 #endif
454 	};
455 
456 	module_assert_mutex_or_preempt();
457 
458 	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
459 		return true;
460 
461 	list_for_each_entry_rcu(mod, &modules, list,
462 				lockdep_is_held(&module_mutex)) {
463 		struct symsearch arr[] = {
464 			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
465 			  NOT_GPL_ONLY, false },
466 			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
467 			  mod->gpl_crcs,
468 			  GPL_ONLY, false },
469 			{ mod->gpl_future_syms,
470 			  mod->gpl_future_syms + mod->num_gpl_future_syms,
471 			  mod->gpl_future_crcs,
472 			  WILL_BE_GPL_ONLY, false },
473 #ifdef CONFIG_UNUSED_SYMBOLS
474 			{ mod->unused_syms,
475 			  mod->unused_syms + mod->num_unused_syms,
476 			  mod->unused_crcs,
477 			  NOT_GPL_ONLY, true },
478 			{ mod->unused_gpl_syms,
479 			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
480 			  mod->unused_gpl_crcs,
481 			  GPL_ONLY, true },
482 #endif
483 		};
484 
485 		if (mod->state == MODULE_STATE_UNFORMED)
486 			continue;
487 
488 		if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
489 			return true;
490 	}
491 	return false;
492 }
493 
494 struct find_symbol_arg {
495 	/* Input */
496 	const char *name;
497 	bool gplok;
498 	bool warn;
499 
500 	/* Output */
501 	struct module *owner;
502 	const s32 *crc;
503 	const struct kernel_symbol *sym;
504 	enum mod_license license;
505 };
506 
check_exported_symbol(const struct symsearch * syms,struct module * owner,unsigned int symnum,void * data)507 static bool check_exported_symbol(const struct symsearch *syms,
508 				  struct module *owner,
509 				  unsigned int symnum, void *data)
510 {
511 	struct find_symbol_arg *fsa = data;
512 
513 	if (!fsa->gplok) {
514 		if (syms->license == GPL_ONLY)
515 			return false;
516 		if (syms->license == WILL_BE_GPL_ONLY && fsa->warn) {
517 			pr_warn("Symbol %s is being used by a non-GPL module, "
518 				"which will not be allowed in the future\n",
519 				fsa->name);
520 		}
521 	}
522 
523 #ifdef CONFIG_UNUSED_SYMBOLS
524 	if (syms->unused && fsa->warn) {
525 		pr_warn("Symbol %s is marked as UNUSED, however this module is "
526 			"using it.\n", fsa->name);
527 		pr_warn("This symbol will go away in the future.\n");
528 		pr_warn("Please evaluate if this is the right api to use and "
529 			"if it really is, submit a report to the linux kernel "
530 			"mailing list together with submitting your code for "
531 			"inclusion.\n");
532 	}
533 #endif
534 
535 	fsa->owner = owner;
536 	fsa->crc = symversion(syms->crcs, symnum);
537 	fsa->sym = &syms->start[symnum];
538 	fsa->license = syms->license;
539 	return true;
540 }
541 
kernel_symbol_value(const struct kernel_symbol * sym)542 static unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
543 {
544 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
545 	return (unsigned long)offset_to_ptr(&sym->value_offset);
546 #else
547 	return sym->value;
548 #endif
549 }
550 
kernel_symbol_name(const struct kernel_symbol * sym)551 static const char *kernel_symbol_name(const struct kernel_symbol *sym)
552 {
553 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
554 	return offset_to_ptr(&sym->name_offset);
555 #else
556 	return sym->name;
557 #endif
558 }
559 
kernel_symbol_namespace(const struct kernel_symbol * sym)560 static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
561 {
562 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
563 	if (!sym->namespace_offset)
564 		return NULL;
565 	return offset_to_ptr(&sym->namespace_offset);
566 #else
567 	return sym->namespace;
568 #endif
569 }
570 
cmp_name(const void * name,const void * sym)571 static int cmp_name(const void *name, const void *sym)
572 {
573 	return strcmp(name, kernel_symbol_name(sym));
574 }
575 
find_exported_symbol_in_section(const struct symsearch * syms,struct module * owner,void * data)576 static bool find_exported_symbol_in_section(const struct symsearch *syms,
577 					    struct module *owner,
578 					    void *data)
579 {
580 	struct find_symbol_arg *fsa = data;
581 	struct kernel_symbol *sym;
582 
583 	sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
584 			sizeof(struct kernel_symbol), cmp_name);
585 
586 	if (sym != NULL && check_exported_symbol(syms, owner,
587 						 sym - syms->start, data))
588 		return true;
589 
590 	return false;
591 }
592 
593 /* Find an exported symbol and return it, along with, (optional) crc and
594  * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
find_symbol(const char * name,struct module ** owner,const s32 ** crc,enum mod_license * license,bool gplok,bool warn)595 static const struct kernel_symbol *find_symbol(const char *name,
596 					struct module **owner,
597 					const s32 **crc,
598 					enum mod_license *license,
599 					bool gplok,
600 					bool warn)
601 {
602 	struct find_symbol_arg fsa;
603 
604 	fsa.name = name;
605 	fsa.gplok = gplok;
606 	fsa.warn = warn;
607 
608 	if (each_symbol_section(find_exported_symbol_in_section, &fsa)) {
609 		if (owner)
610 			*owner = fsa.owner;
611 		if (crc)
612 			*crc = fsa.crc;
613 		if (license)
614 			*license = fsa.license;
615 		return fsa.sym;
616 	}
617 
618 	pr_debug("Failed to find symbol %s\n", name);
619 	return NULL;
620 }
621 
622 /*
623  * Search for module by name: must hold module_mutex (or preempt disabled
624  * for read-only access).
625  */
find_module_all(const char * name,size_t len,bool even_unformed)626 static struct module *find_module_all(const char *name, size_t len,
627 				      bool even_unformed)
628 {
629 	struct module *mod;
630 
631 	module_assert_mutex_or_preempt();
632 
633 	list_for_each_entry_rcu(mod, &modules, list,
634 				lockdep_is_held(&module_mutex)) {
635 		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
636 			continue;
637 		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
638 			return mod;
639 	}
640 	return NULL;
641 }
642 
find_module(const char * name)643 struct module *find_module(const char *name)
644 {
645 	module_assert_mutex();
646 	return find_module_all(name, strlen(name), false);
647 }
648 EXPORT_SYMBOL_GPL(find_module);
649 
650 #ifdef CONFIG_SMP
651 
mod_percpu(struct module * mod)652 static inline void __percpu *mod_percpu(struct module *mod)
653 {
654 	return mod->percpu;
655 }
656 
percpu_modalloc(struct module * mod,struct load_info * info)657 static int percpu_modalloc(struct module *mod, struct load_info *info)
658 {
659 	Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
660 	unsigned long align = pcpusec->sh_addralign;
661 
662 	if (!pcpusec->sh_size)
663 		return 0;
664 
665 	if (align > PAGE_SIZE) {
666 		pr_warn("%s: per-cpu alignment %li > %li\n",
667 			mod->name, align, PAGE_SIZE);
668 		align = PAGE_SIZE;
669 	}
670 
671 	mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
672 	if (!mod->percpu) {
673 		pr_warn("%s: Could not allocate %lu bytes percpu data\n",
674 			mod->name, (unsigned long)pcpusec->sh_size);
675 		return -ENOMEM;
676 	}
677 	mod->percpu_size = pcpusec->sh_size;
678 	return 0;
679 }
680 
percpu_modfree(struct module * mod)681 static void percpu_modfree(struct module *mod)
682 {
683 	free_percpu(mod->percpu);
684 }
685 
find_pcpusec(struct load_info * info)686 static unsigned int find_pcpusec(struct load_info *info)
687 {
688 	return find_sec(info, ".data..percpu");
689 }
690 
percpu_modcopy(struct module * mod,const void * from,unsigned long size)691 static void percpu_modcopy(struct module *mod,
692 			   const void *from, unsigned long size)
693 {
694 	int cpu;
695 
696 	for_each_possible_cpu(cpu)
697 		memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
698 }
699 
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)700 bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
701 {
702 	struct module *mod;
703 	unsigned int cpu;
704 
705 	preempt_disable();
706 
707 	list_for_each_entry_rcu(mod, &modules, list) {
708 		if (mod->state == MODULE_STATE_UNFORMED)
709 			continue;
710 		if (!mod->percpu_size)
711 			continue;
712 		for_each_possible_cpu(cpu) {
713 			void *start = per_cpu_ptr(mod->percpu, cpu);
714 			void *va = (void *)addr;
715 
716 			if (va >= start && va < start + mod->percpu_size) {
717 				if (can_addr) {
718 					*can_addr = (unsigned long) (va - start);
719 					*can_addr += (unsigned long)
720 						per_cpu_ptr(mod->percpu,
721 							    get_boot_cpu_id());
722 				}
723 				preempt_enable();
724 				return true;
725 			}
726 		}
727 	}
728 
729 	preempt_enable();
730 	return false;
731 }
732 
733 /**
734  * is_module_percpu_address - test whether address is from module static percpu
735  * @addr: address to test
736  *
737  * Test whether @addr belongs to module static percpu area.
738  *
739  * RETURNS:
740  * %true if @addr is from module static percpu area
741  */
is_module_percpu_address(unsigned long addr)742 bool is_module_percpu_address(unsigned long addr)
743 {
744 	return __is_module_percpu_address(addr, NULL);
745 }
746 
747 #else /* ... !CONFIG_SMP */
748 
mod_percpu(struct module * mod)749 static inline void __percpu *mod_percpu(struct module *mod)
750 {
751 	return NULL;
752 }
percpu_modalloc(struct module * mod,struct load_info * info)753 static int percpu_modalloc(struct module *mod, struct load_info *info)
754 {
755 	/* UP modules shouldn't have this section: ENOMEM isn't quite right */
756 	if (info->sechdrs[info->index.pcpu].sh_size != 0)
757 		return -ENOMEM;
758 	return 0;
759 }
percpu_modfree(struct module * mod)760 static inline void percpu_modfree(struct module *mod)
761 {
762 }
find_pcpusec(struct load_info * info)763 static unsigned int find_pcpusec(struct load_info *info)
764 {
765 	return 0;
766 }
percpu_modcopy(struct module * mod,const void * from,unsigned long size)767 static inline void percpu_modcopy(struct module *mod,
768 				  const void *from, unsigned long size)
769 {
770 	/* pcpusec should be 0, and size of that section should be 0. */
771 	BUG_ON(size != 0);
772 }
is_module_percpu_address(unsigned long addr)773 bool is_module_percpu_address(unsigned long addr)
774 {
775 	return false;
776 }
777 
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)778 bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
779 {
780 	return false;
781 }
782 
783 #endif /* CONFIG_SMP */
784 
785 #define MODINFO_ATTR(field)	\
786 static void setup_modinfo_##field(struct module *mod, const char *s)  \
787 {                                                                     \
788 	mod->field = kstrdup(s, GFP_KERNEL);                          \
789 }                                                                     \
790 static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
791 			struct module_kobject *mk, char *buffer)      \
792 {                                                                     \
793 	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
794 }                                                                     \
795 static int modinfo_##field##_exists(struct module *mod)               \
796 {                                                                     \
797 	return mod->field != NULL;                                    \
798 }                                                                     \
799 static void free_modinfo_##field(struct module *mod)                  \
800 {                                                                     \
801 	kfree(mod->field);                                            \
802 	mod->field = NULL;                                            \
803 }                                                                     \
804 static struct module_attribute modinfo_##field = {                    \
805 	.attr = { .name = __stringify(field), .mode = 0444 },         \
806 	.show = show_modinfo_##field,                                 \
807 	.setup = setup_modinfo_##field,                               \
808 	.test = modinfo_##field##_exists,                             \
809 	.free = free_modinfo_##field,                                 \
810 };
811 
812 MODINFO_ATTR(version);
813 MODINFO_ATTR(srcversion);
814 
815 static char last_unloaded_module[MODULE_NAME_LEN+1];
816 
817 #ifdef CONFIG_MODULE_UNLOAD
818 
819 EXPORT_TRACEPOINT_SYMBOL(module_get);
820 
821 /* MODULE_REF_BASE is the base reference count by kmodule loader. */
822 #define MODULE_REF_BASE	1
823 
824 /* Init the unload section of the module. */
module_unload_init(struct module * mod)825 static int module_unload_init(struct module *mod)
826 {
827 	/*
828 	 * Initialize reference counter to MODULE_REF_BASE.
829 	 * refcnt == 0 means module is going.
830 	 */
831 	atomic_set(&mod->refcnt, MODULE_REF_BASE);
832 
833 	INIT_LIST_HEAD(&mod->source_list);
834 	INIT_LIST_HEAD(&mod->target_list);
835 
836 	/* Hold reference count during initialization. */
837 	atomic_inc(&mod->refcnt);
838 
839 	return 0;
840 }
841 
842 /* Does a already use b? */
already_uses(struct module * a,struct module * b)843 static int already_uses(struct module *a, struct module *b)
844 {
845 	struct module_use *use;
846 
847 	list_for_each_entry(use, &b->source_list, source_list) {
848 		if (use->source == a) {
849 			pr_debug("%s uses %s!\n", a->name, b->name);
850 			return 1;
851 		}
852 	}
853 	pr_debug("%s does not use %s!\n", a->name, b->name);
854 	return 0;
855 }
856 
857 /*
858  * Module a uses b
859  *  - we add 'a' as a "source", 'b' as a "target" of module use
860  *  - the module_use is added to the list of 'b' sources (so
861  *    'b' can walk the list to see who sourced them), and of 'a'
862  *    targets (so 'a' can see what modules it targets).
863  */
add_module_usage(struct module * a,struct module * b)864 static int add_module_usage(struct module *a, struct module *b)
865 {
866 	struct module_use *use;
867 
868 	pr_debug("Allocating new usage for %s.\n", a->name);
869 	use = kmalloc(sizeof(*use), GFP_ATOMIC);
870 	if (!use)
871 		return -ENOMEM;
872 
873 	use->source = a;
874 	use->target = b;
875 	list_add(&use->source_list, &b->source_list);
876 	list_add(&use->target_list, &a->target_list);
877 	return 0;
878 }
879 
880 /* Module a uses b: caller needs module_mutex() */
ref_module(struct module * a,struct module * b)881 static int ref_module(struct module *a, struct module *b)
882 {
883 	int err;
884 
885 	if (b == NULL || already_uses(a, b))
886 		return 0;
887 
888 	/* If module isn't available, we fail. */
889 	err = strong_try_module_get(b);
890 	if (err)
891 		return err;
892 
893 	err = add_module_usage(a, b);
894 	if (err) {
895 		module_put(b);
896 		return err;
897 	}
898 	return 0;
899 }
900 
901 /* Clear the unload stuff of the module. */
module_unload_free(struct module * mod)902 static void module_unload_free(struct module *mod)
903 {
904 	struct module_use *use, *tmp;
905 
906 	mutex_lock(&module_mutex);
907 	list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
908 		struct module *i = use->target;
909 		pr_debug("%s unusing %s\n", mod->name, i->name);
910 		module_put(i);
911 		list_del(&use->source_list);
912 		list_del(&use->target_list);
913 		kfree(use);
914 	}
915 	mutex_unlock(&module_mutex);
916 }
917 
918 #ifdef CONFIG_MODULE_FORCE_UNLOAD
try_force_unload(unsigned int flags)919 static inline int try_force_unload(unsigned int flags)
920 {
921 	int ret = (flags & O_TRUNC);
922 	if (ret)
923 		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
924 	return ret;
925 }
926 #else
try_force_unload(unsigned int flags)927 static inline int try_force_unload(unsigned int flags)
928 {
929 	return 0;
930 }
931 #endif /* CONFIG_MODULE_FORCE_UNLOAD */
932 
933 /* Try to release refcount of module, 0 means success. */
try_release_module_ref(struct module * mod)934 static int try_release_module_ref(struct module *mod)
935 {
936 	int ret;
937 
938 	/* Try to decrement refcnt which we set at loading */
939 	ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt);
940 	BUG_ON(ret < 0);
941 	if (ret)
942 		/* Someone can put this right now, recover with checking */
943 		ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0);
944 
945 	return ret;
946 }
947 
try_stop_module(struct module * mod,int flags,int * forced)948 static int try_stop_module(struct module *mod, int flags, int *forced)
949 {
950 	/* If it's not unused, quit unless we're forcing. */
951 	if (try_release_module_ref(mod) != 0) {
952 		*forced = try_force_unload(flags);
953 		if (!(*forced))
954 			return -EWOULDBLOCK;
955 	}
956 
957 	/* Mark it as dying. */
958 	mod->state = MODULE_STATE_GOING;
959 
960 	return 0;
961 }
962 
963 /**
964  * module_refcount - return the refcount or -1 if unloading
965  *
966  * @mod:	the module we're checking
967  *
968  * Returns:
969  *	-1 if the module is in the process of unloading
970  *	otherwise the number of references in the kernel to the module
971  */
module_refcount(struct module * mod)972 int module_refcount(struct module *mod)
973 {
974 	return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
975 }
976 EXPORT_SYMBOL(module_refcount);
977 
978 /* This exists whether we can unload or not */
979 static void free_module(struct module *mod);
980 
SYSCALL_DEFINE2(delete_module,const char __user *,name_user,unsigned int,flags)981 SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
982 		unsigned int, flags)
983 {
984 	struct module *mod;
985 	char name[MODULE_NAME_LEN];
986 	int ret, forced = 0;
987 
988 	if (!capable(CAP_SYS_MODULE) || modules_disabled)
989 		return -EPERM;
990 
991 	if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
992 		return -EFAULT;
993 	name[MODULE_NAME_LEN-1] = '\0';
994 
995 	audit_log_kern_module(name);
996 
997 	if (mutex_lock_interruptible(&module_mutex) != 0)
998 		return -EINTR;
999 
1000 	mod = find_module(name);
1001 	if (!mod) {
1002 		ret = -ENOENT;
1003 		goto out;
1004 	}
1005 
1006 	if (!list_empty(&mod->source_list)) {
1007 		/* Other modules depend on us: get rid of them first. */
1008 		ret = -EWOULDBLOCK;
1009 		goto out;
1010 	}
1011 
1012 	/* Doing init or already dying? */
1013 	if (mod->state != MODULE_STATE_LIVE) {
1014 		/* FIXME: if (force), slam module count damn the torpedoes */
1015 		pr_debug("%s already dying\n", mod->name);
1016 		ret = -EBUSY;
1017 		goto out;
1018 	}
1019 
1020 	/* If it has an init func, it must have an exit func to unload */
1021 	if (mod->init && !mod->exit) {
1022 		forced = try_force_unload(flags);
1023 		if (!forced) {
1024 			/* This module can't be removed */
1025 			ret = -EBUSY;
1026 			goto out;
1027 		}
1028 	}
1029 
1030 	/* Stop the machine so refcounts can't move and disable module. */
1031 	ret = try_stop_module(mod, flags, &forced);
1032 	if (ret != 0)
1033 		goto out;
1034 
1035 	mutex_unlock(&module_mutex);
1036 	/* Final destruction now no one is using it. */
1037 	if (mod->exit != NULL)
1038 		mod->exit();
1039 	blocking_notifier_call_chain(&module_notify_list,
1040 				     MODULE_STATE_GOING, mod);
1041 	klp_module_going(mod);
1042 	ftrace_release_mod(mod);
1043 
1044 	async_synchronize_full();
1045 
1046 	/* Store the name of the last unloaded module for diagnostic purposes */
1047 	strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
1048 
1049 	free_module(mod);
1050 	/* someone could wait for the module in add_unformed_module() */
1051 	wake_up_all(&module_wq);
1052 	return 0;
1053 out:
1054 	mutex_unlock(&module_mutex);
1055 	return ret;
1056 }
1057 
print_unload_info(struct seq_file * m,struct module * mod)1058 static inline void print_unload_info(struct seq_file *m, struct module *mod)
1059 {
1060 	struct module_use *use;
1061 	int printed_something = 0;
1062 
1063 	seq_printf(m, " %i ", module_refcount(mod));
1064 
1065 	/*
1066 	 * Always include a trailing , so userspace can differentiate
1067 	 * between this and the old multi-field proc format.
1068 	 */
1069 	list_for_each_entry(use, &mod->source_list, source_list) {
1070 		printed_something = 1;
1071 		seq_printf(m, "%s,", use->source->name);
1072 	}
1073 
1074 	if (mod->init != NULL && mod->exit == NULL) {
1075 		printed_something = 1;
1076 		seq_puts(m, "[permanent],");
1077 	}
1078 
1079 	if (!printed_something)
1080 		seq_puts(m, "-");
1081 }
1082 
__symbol_put(const char * symbol)1083 void __symbol_put(const char *symbol)
1084 {
1085 	struct module *owner;
1086 
1087 	preempt_disable();
1088 	if (!find_symbol(symbol, &owner, NULL, NULL, true, false))
1089 		BUG();
1090 	module_put(owner);
1091 	preempt_enable();
1092 }
1093 EXPORT_SYMBOL(__symbol_put);
1094 
1095 /* Note this assumes addr is a function, which it currently always is. */
symbol_put_addr(void * addr)1096 void symbol_put_addr(void *addr)
1097 {
1098 	struct module *modaddr;
1099 	unsigned long a = (unsigned long)dereference_function_descriptor(addr);
1100 
1101 	if (core_kernel_text(a))
1102 		return;
1103 
1104 	/*
1105 	 * Even though we hold a reference on the module; we still need to
1106 	 * disable preemption in order to safely traverse the data structure.
1107 	 */
1108 	preempt_disable();
1109 	modaddr = __module_text_address(a);
1110 	BUG_ON(!modaddr);
1111 	module_put(modaddr);
1112 	preempt_enable();
1113 }
1114 EXPORT_SYMBOL_GPL(symbol_put_addr);
1115 
show_refcnt(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1116 static ssize_t show_refcnt(struct module_attribute *mattr,
1117 			   struct module_kobject *mk, char *buffer)
1118 {
1119 	return sprintf(buffer, "%i\n", module_refcount(mk->mod));
1120 }
1121 
1122 static struct module_attribute modinfo_refcnt =
1123 	__ATTR(refcnt, 0444, show_refcnt, NULL);
1124 
__module_get(struct module * module)1125 void __module_get(struct module *module)
1126 {
1127 	if (module) {
1128 		preempt_disable();
1129 		atomic_inc(&module->refcnt);
1130 		trace_module_get(module, _RET_IP_);
1131 		preempt_enable();
1132 	}
1133 }
1134 EXPORT_SYMBOL(__module_get);
1135 
try_module_get(struct module * module)1136 bool try_module_get(struct module *module)
1137 {
1138 	bool ret = true;
1139 
1140 	if (module) {
1141 		preempt_disable();
1142 		/* Note: here, we can fail to get a reference */
1143 		if (likely(module_is_live(module) &&
1144 			   atomic_inc_not_zero(&module->refcnt) != 0))
1145 			trace_module_get(module, _RET_IP_);
1146 		else
1147 			ret = false;
1148 
1149 		preempt_enable();
1150 	}
1151 	return ret;
1152 }
1153 EXPORT_SYMBOL(try_module_get);
1154 
module_put(struct module * module)1155 void module_put(struct module *module)
1156 {
1157 	int ret;
1158 
1159 	if (module) {
1160 		preempt_disable();
1161 		ret = atomic_dec_if_positive(&module->refcnt);
1162 		WARN_ON(ret < 0);	/* Failed to put refcount */
1163 		trace_module_put(module, _RET_IP_);
1164 		preempt_enable();
1165 	}
1166 }
1167 EXPORT_SYMBOL(module_put);
1168 
1169 #else /* !CONFIG_MODULE_UNLOAD */
print_unload_info(struct seq_file * m,struct module * mod)1170 static inline void print_unload_info(struct seq_file *m, struct module *mod)
1171 {
1172 	/* We don't know the usage count, or what modules are using. */
1173 	seq_puts(m, " - -");
1174 }
1175 
module_unload_free(struct module * mod)1176 static inline void module_unload_free(struct module *mod)
1177 {
1178 }
1179 
ref_module(struct module * a,struct module * b)1180 static int ref_module(struct module *a, struct module *b)
1181 {
1182 	return strong_try_module_get(b);
1183 }
1184 
module_unload_init(struct module * mod)1185 static inline int module_unload_init(struct module *mod)
1186 {
1187 	return 0;
1188 }
1189 #endif /* CONFIG_MODULE_UNLOAD */
1190 
module_flags_taint(struct module * mod,char * buf)1191 static size_t module_flags_taint(struct module *mod, char *buf)
1192 {
1193 	size_t l = 0;
1194 	int i;
1195 
1196 	for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
1197 		if (taint_flags[i].module && test_bit(i, &mod->taints))
1198 			buf[l++] = taint_flags[i].c_true;
1199 	}
1200 
1201 	return l;
1202 }
1203 
show_initstate(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1204 static ssize_t show_initstate(struct module_attribute *mattr,
1205 			      struct module_kobject *mk, char *buffer)
1206 {
1207 	const char *state = "unknown";
1208 
1209 	switch (mk->mod->state) {
1210 	case MODULE_STATE_LIVE:
1211 		state = "live";
1212 		break;
1213 	case MODULE_STATE_COMING:
1214 		state = "coming";
1215 		break;
1216 	case MODULE_STATE_GOING:
1217 		state = "going";
1218 		break;
1219 	default:
1220 		BUG();
1221 	}
1222 	return sprintf(buffer, "%s\n", state);
1223 }
1224 
1225 static struct module_attribute modinfo_initstate =
1226 	__ATTR(initstate, 0444, show_initstate, NULL);
1227 
store_uevent(struct module_attribute * mattr,struct module_kobject * mk,const char * buffer,size_t count)1228 static ssize_t store_uevent(struct module_attribute *mattr,
1229 			    struct module_kobject *mk,
1230 			    const char *buffer, size_t count)
1231 {
1232 	int rc;
1233 
1234 	rc = kobject_synth_uevent(&mk->kobj, buffer, count);
1235 	return rc ? rc : count;
1236 }
1237 
1238 struct module_attribute module_uevent =
1239 	__ATTR(uevent, 0200, NULL, store_uevent);
1240 
show_coresize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1241 static ssize_t show_coresize(struct module_attribute *mattr,
1242 			     struct module_kobject *mk, char *buffer)
1243 {
1244 	return sprintf(buffer, "%u\n", mk->mod->core_layout.size);
1245 }
1246 
1247 static struct module_attribute modinfo_coresize =
1248 	__ATTR(coresize, 0444, show_coresize, NULL);
1249 
show_initsize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1250 static ssize_t show_initsize(struct module_attribute *mattr,
1251 			     struct module_kobject *mk, char *buffer)
1252 {
1253 	return sprintf(buffer, "%u\n", mk->mod->init_layout.size);
1254 }
1255 
1256 static struct module_attribute modinfo_initsize =
1257 	__ATTR(initsize, 0444, show_initsize, NULL);
1258 
show_taint(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1259 static ssize_t show_taint(struct module_attribute *mattr,
1260 			  struct module_kobject *mk, char *buffer)
1261 {
1262 	size_t l;
1263 
1264 	l = module_flags_taint(mk->mod, buffer);
1265 	buffer[l++] = '\n';
1266 	return l;
1267 }
1268 
1269 static struct module_attribute modinfo_taint =
1270 	__ATTR(taint, 0444, show_taint, NULL);
1271 
1272 static struct module_attribute *modinfo_attrs[] = {
1273 	&module_uevent,
1274 	&modinfo_version,
1275 	&modinfo_srcversion,
1276 	&modinfo_initstate,
1277 	&modinfo_coresize,
1278 	&modinfo_initsize,
1279 	&modinfo_taint,
1280 #ifdef CONFIG_MODULE_UNLOAD
1281 	&modinfo_refcnt,
1282 #endif
1283 	NULL,
1284 };
1285 
1286 static const char vermagic[] = VERMAGIC_STRING;
1287 
try_to_force_load(struct module * mod,const char * reason)1288 static int try_to_force_load(struct module *mod, const char *reason)
1289 {
1290 #ifdef CONFIG_MODULE_FORCE_LOAD
1291 	if (!test_taint(TAINT_FORCED_MODULE))
1292 		pr_warn("%s: %s: kernel tainted.\n", mod->name, reason);
1293 	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
1294 	return 0;
1295 #else
1296 	return -ENOEXEC;
1297 #endif
1298 }
1299 
1300 #ifdef CONFIG_MODVERSIONS
1301 
resolve_rel_crc(const s32 * crc)1302 static u32 resolve_rel_crc(const s32 *crc)
1303 {
1304 	return *(u32 *)((void *)crc + *crc);
1305 }
1306 
check_version(const struct load_info * info,const char * symname,struct module * mod,const s32 * crc)1307 static int check_version(const struct load_info *info,
1308 			 const char *symname,
1309 			 struct module *mod,
1310 			 const s32 *crc)
1311 {
1312 	Elf_Shdr *sechdrs = info->sechdrs;
1313 	unsigned int versindex = info->index.vers;
1314 	unsigned int i, num_versions;
1315 	struct modversion_info *versions;
1316 
1317 	/* Exporting module didn't supply crcs?  OK, we're already tainted. */
1318 	if (!crc)
1319 		return 1;
1320 
1321 	/* No versions at all?  modprobe --force does this. */
1322 	if (versindex == 0)
1323 		return try_to_force_load(mod, symname) == 0;
1324 
1325 	versions = (void *) sechdrs[versindex].sh_addr;
1326 	num_versions = sechdrs[versindex].sh_size
1327 		/ sizeof(struct modversion_info);
1328 
1329 	for (i = 0; i < num_versions; i++) {
1330 		u32 crcval;
1331 
1332 		if (strcmp(versions[i].name, symname) != 0)
1333 			continue;
1334 
1335 		if (IS_ENABLED(CONFIG_MODULE_REL_CRCS))
1336 			crcval = resolve_rel_crc(crc);
1337 		else
1338 			crcval = *crc;
1339 		if (versions[i].crc == crcval)
1340 			return 1;
1341 		pr_debug("Found checksum %X vs module %lX\n",
1342 			 crcval, versions[i].crc);
1343 		goto bad_version;
1344 	}
1345 
1346 	/* Broken toolchain. Warn once, then let it go.. */
1347 	pr_warn_once("%s: no symbol version for %s\n", info->name, symname);
1348 	return 1;
1349 
1350 bad_version:
1351 	pr_warn("%s: disagrees about version of symbol %s\n",
1352 	       info->name, symname);
1353 	return 0;
1354 }
1355 
check_modstruct_version(const struct load_info * info,struct module * mod)1356 static inline int check_modstruct_version(const struct load_info *info,
1357 					  struct module *mod)
1358 {
1359 	const s32 *crc;
1360 
1361 	/*
1362 	 * Since this should be found in kernel (which can't be removed), no
1363 	 * locking is necessary -- use preempt_disable() to placate lockdep.
1364 	 */
1365 	preempt_disable();
1366 	if (!find_symbol("module_layout", NULL, &crc, NULL, true, false)) {
1367 		preempt_enable();
1368 		BUG();
1369 	}
1370 	preempt_enable();
1371 	return check_version(info, "module_layout", mod, crc);
1372 }
1373 
1374 /* First part is kernel version, which we ignore if module has crcs. */
same_magic(const char * amagic,const char * bmagic,bool has_crcs)1375 static inline int same_magic(const char *amagic, const char *bmagic,
1376 			     bool has_crcs)
1377 {
1378 	if (has_crcs) {
1379 		amagic += strcspn(amagic, " ");
1380 		bmagic += strcspn(bmagic, " ");
1381 	}
1382 	return strcmp(amagic, bmagic) == 0;
1383 }
1384 #else
check_version(const struct load_info * info,const char * symname,struct module * mod,const s32 * crc)1385 static inline int check_version(const struct load_info *info,
1386 				const char *symname,
1387 				struct module *mod,
1388 				const s32 *crc)
1389 {
1390 	return 1;
1391 }
1392 
check_modstruct_version(const struct load_info * info,struct module * mod)1393 static inline int check_modstruct_version(const struct load_info *info,
1394 					  struct module *mod)
1395 {
1396 	return 1;
1397 }
1398 
same_magic(const char * amagic,const char * bmagic,bool has_crcs)1399 static inline int same_magic(const char *amagic, const char *bmagic,
1400 			     bool has_crcs)
1401 {
1402 	return strcmp(amagic, bmagic) == 0;
1403 }
1404 #endif /* CONFIG_MODVERSIONS */
1405 
1406 static char *get_modinfo(const struct load_info *info, const char *tag);
1407 static char *get_next_modinfo(const struct load_info *info, const char *tag,
1408 			      char *prev);
1409 
verify_namespace_is_imported(const struct load_info * info,const struct kernel_symbol * sym,struct module * mod)1410 static int verify_namespace_is_imported(const struct load_info *info,
1411 					const struct kernel_symbol *sym,
1412 					struct module *mod)
1413 {
1414 	const char *namespace;
1415 	char *imported_namespace;
1416 
1417 	namespace = kernel_symbol_namespace(sym);
1418 	if (namespace && namespace[0]) {
1419 		imported_namespace = get_modinfo(info, "import_ns");
1420 		while (imported_namespace) {
1421 			if (strcmp(namespace, imported_namespace) == 0)
1422 				return 0;
1423 			imported_namespace = get_next_modinfo(
1424 				info, "import_ns", imported_namespace);
1425 		}
1426 #ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1427 		pr_warn(
1428 #else
1429 		pr_err(
1430 #endif
1431 			"%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
1432 			mod->name, kernel_symbol_name(sym), namespace);
1433 #ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1434 		return -EINVAL;
1435 #endif
1436 	}
1437 	return 0;
1438 }
1439 
inherit_taint(struct module * mod,struct module * owner)1440 static bool inherit_taint(struct module *mod, struct module *owner)
1441 {
1442 	if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
1443 		return true;
1444 
1445 	if (mod->using_gplonly_symbols) {
1446 		pr_err("%s: module using GPL-only symbols uses symbols from proprietary module %s.\n",
1447 			mod->name, owner->name);
1448 		return false;
1449 	}
1450 
1451 	if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
1452 		pr_warn("%s: module uses symbols from proprietary module %s, inheriting taint.\n",
1453 			mod->name, owner->name);
1454 		set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
1455 	}
1456 	return true;
1457 }
1458 
1459 /* Resolve a symbol for this module.  I.e. if we find one, record usage. */
resolve_symbol(struct module * mod,const struct load_info * info,const char * name,char ownername[])1460 static const struct kernel_symbol *resolve_symbol(struct module *mod,
1461 						  const struct load_info *info,
1462 						  const char *name,
1463 						  char ownername[])
1464 {
1465 	struct module *owner;
1466 	const struct kernel_symbol *sym;
1467 	const s32 *crc;
1468 	enum mod_license license;
1469 	int err;
1470 
1471 	/*
1472 	 * The module_mutex should not be a heavily contended lock;
1473 	 * if we get the occasional sleep here, we'll go an extra iteration
1474 	 * in the wait_event_interruptible(), which is harmless.
1475 	 */
1476 	sched_annotate_sleep();
1477 	mutex_lock(&module_mutex);
1478 	sym = find_symbol(name, &owner, &crc, &license,
1479 			  !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)), true);
1480 	if (!sym)
1481 		goto unlock;
1482 
1483 	if (license == GPL_ONLY)
1484 		mod->using_gplonly_symbols = true;
1485 
1486 	if (!inherit_taint(mod, owner)) {
1487 		sym = NULL;
1488 		goto getname;
1489 	}
1490 
1491 	if (!check_version(info, name, mod, crc)) {
1492 		sym = ERR_PTR(-EINVAL);
1493 		goto getname;
1494 	}
1495 
1496 	err = verify_namespace_is_imported(info, sym, mod);
1497 	if (err) {
1498 		sym = ERR_PTR(err);
1499 		goto getname;
1500 	}
1501 
1502 	err = ref_module(mod, owner);
1503 	if (err) {
1504 		sym = ERR_PTR(err);
1505 		goto getname;
1506 	}
1507 
1508 getname:
1509 	/* We must make copy under the lock if we failed to get ref. */
1510 	strncpy(ownername, module_name(owner), MODULE_NAME_LEN);
1511 unlock:
1512 	mutex_unlock(&module_mutex);
1513 	return sym;
1514 }
1515 
1516 static const struct kernel_symbol *
resolve_symbol_wait(struct module * mod,const struct load_info * info,const char * name)1517 resolve_symbol_wait(struct module *mod,
1518 		    const struct load_info *info,
1519 		    const char *name)
1520 {
1521 	const struct kernel_symbol *ksym;
1522 	char owner[MODULE_NAME_LEN];
1523 
1524 	if (wait_event_interruptible_timeout(module_wq,
1525 			!IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
1526 			|| PTR_ERR(ksym) != -EBUSY,
1527 					     30 * HZ) <= 0) {
1528 		pr_warn("%s: gave up waiting for init of module %s.\n",
1529 			mod->name, owner);
1530 	}
1531 	return ksym;
1532 }
1533 
1534 /*
1535  * /sys/module/foo/sections stuff
1536  * J. Corbet <corbet@lwn.net>
1537  */
1538 #ifdef CONFIG_SYSFS
1539 
1540 #ifdef CONFIG_KALLSYMS
sect_empty(const Elf_Shdr * sect)1541 static inline bool sect_empty(const Elf_Shdr *sect)
1542 {
1543 	return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
1544 }
1545 
1546 struct module_sect_attr {
1547 	struct bin_attribute battr;
1548 	unsigned long address;
1549 };
1550 
1551 struct module_sect_attrs {
1552 	struct attribute_group grp;
1553 	unsigned int nsections;
1554 	struct module_sect_attr attrs[];
1555 };
1556 
1557 #define MODULE_SECT_READ_SIZE (3 /* "0x", "\n" */ + (BITS_PER_LONG / 4))
module_sect_read(struct file * file,struct kobject * kobj,struct bin_attribute * battr,char * buf,loff_t pos,size_t count)1558 static ssize_t module_sect_read(struct file *file, struct kobject *kobj,
1559 				struct bin_attribute *battr,
1560 				char *buf, loff_t pos, size_t count)
1561 {
1562 	struct module_sect_attr *sattr =
1563 		container_of(battr, struct module_sect_attr, battr);
1564 	char bounce[MODULE_SECT_READ_SIZE + 1];
1565 	size_t wrote;
1566 
1567 	if (pos != 0)
1568 		return -EINVAL;
1569 
1570 	/*
1571 	 * Since we're a binary read handler, we must account for the
1572 	 * trailing NUL byte that sprintf will write: if "buf" is
1573 	 * too small to hold the NUL, or the NUL is exactly the last
1574 	 * byte, the read will look like it got truncated by one byte.
1575 	 * Since there is no way to ask sprintf nicely to not write
1576 	 * the NUL, we have to use a bounce buffer.
1577 	 */
1578 	wrote = scnprintf(bounce, sizeof(bounce), "0x%px\n",
1579 			 kallsyms_show_value(file->f_cred)
1580 				? (void *)sattr->address : NULL);
1581 	count = min(count, wrote);
1582 	memcpy(buf, bounce, count);
1583 
1584 	return count;
1585 }
1586 
free_sect_attrs(struct module_sect_attrs * sect_attrs)1587 static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
1588 {
1589 	unsigned int section;
1590 
1591 	for (section = 0; section < sect_attrs->nsections; section++)
1592 		kfree(sect_attrs->attrs[section].battr.attr.name);
1593 	kfree(sect_attrs);
1594 }
1595 
add_sect_attrs(struct module * mod,const struct load_info * info)1596 static void add_sect_attrs(struct module *mod, const struct load_info *info)
1597 {
1598 	unsigned int nloaded = 0, i, size[2];
1599 	struct module_sect_attrs *sect_attrs;
1600 	struct module_sect_attr *sattr;
1601 	struct bin_attribute **gattr;
1602 
1603 	/* Count loaded sections and allocate structures */
1604 	for (i = 0; i < info->hdr->e_shnum; i++)
1605 		if (!sect_empty(&info->sechdrs[i]))
1606 			nloaded++;
1607 	size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded),
1608 			sizeof(sect_attrs->grp.bin_attrs[0]));
1609 	size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]);
1610 	sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
1611 	if (sect_attrs == NULL)
1612 		return;
1613 
1614 	/* Setup section attributes. */
1615 	sect_attrs->grp.name = "sections";
1616 	sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0];
1617 
1618 	sect_attrs->nsections = 0;
1619 	sattr = &sect_attrs->attrs[0];
1620 	gattr = &sect_attrs->grp.bin_attrs[0];
1621 	for (i = 0; i < info->hdr->e_shnum; i++) {
1622 		Elf_Shdr *sec = &info->sechdrs[i];
1623 		if (sect_empty(sec))
1624 			continue;
1625 		sysfs_bin_attr_init(&sattr->battr);
1626 		sattr->address = sec->sh_addr;
1627 		sattr->battr.attr.name =
1628 			kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL);
1629 		if (sattr->battr.attr.name == NULL)
1630 			goto out;
1631 		sect_attrs->nsections++;
1632 		sattr->battr.read = module_sect_read;
1633 		sattr->battr.size = MODULE_SECT_READ_SIZE;
1634 		sattr->battr.attr.mode = 0400;
1635 		*(gattr++) = &(sattr++)->battr;
1636 	}
1637 	*gattr = NULL;
1638 
1639 	if (sysfs_create_group(&mod->mkobj.kobj, &sect_attrs->grp))
1640 		goto out;
1641 
1642 	mod->sect_attrs = sect_attrs;
1643 	return;
1644   out:
1645 	free_sect_attrs(sect_attrs);
1646 }
1647 
remove_sect_attrs(struct module * mod)1648 static void remove_sect_attrs(struct module *mod)
1649 {
1650 	if (mod->sect_attrs) {
1651 		sysfs_remove_group(&mod->mkobj.kobj,
1652 				   &mod->sect_attrs->grp);
1653 		/* We are positive that no one is using any sect attrs
1654 		 * at this point.  Deallocate immediately. */
1655 		free_sect_attrs(mod->sect_attrs);
1656 		mod->sect_attrs = NULL;
1657 	}
1658 }
1659 
1660 /*
1661  * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
1662  */
1663 
1664 struct module_notes_attrs {
1665 	struct kobject *dir;
1666 	unsigned int notes;
1667 	struct bin_attribute attrs[];
1668 };
1669 
module_notes_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t count)1670 static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
1671 				 struct bin_attribute *bin_attr,
1672 				 char *buf, loff_t pos, size_t count)
1673 {
1674 	/*
1675 	 * The caller checked the pos and count against our size.
1676 	 */
1677 	memcpy(buf, bin_attr->private + pos, count);
1678 	return count;
1679 }
1680 
free_notes_attrs(struct module_notes_attrs * notes_attrs,unsigned int i)1681 static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
1682 			     unsigned int i)
1683 {
1684 	if (notes_attrs->dir) {
1685 		while (i-- > 0)
1686 			sysfs_remove_bin_file(notes_attrs->dir,
1687 					      &notes_attrs->attrs[i]);
1688 		kobject_put(notes_attrs->dir);
1689 	}
1690 	kfree(notes_attrs);
1691 }
1692 
add_notes_attrs(struct module * mod,const struct load_info * info)1693 static void add_notes_attrs(struct module *mod, const struct load_info *info)
1694 {
1695 	unsigned int notes, loaded, i;
1696 	struct module_notes_attrs *notes_attrs;
1697 	struct bin_attribute *nattr;
1698 
1699 	/* failed to create section attributes, so can't create notes */
1700 	if (!mod->sect_attrs)
1701 		return;
1702 
1703 	/* Count notes sections and allocate structures.  */
1704 	notes = 0;
1705 	for (i = 0; i < info->hdr->e_shnum; i++)
1706 		if (!sect_empty(&info->sechdrs[i]) &&
1707 		    (info->sechdrs[i].sh_type == SHT_NOTE))
1708 			++notes;
1709 
1710 	if (notes == 0)
1711 		return;
1712 
1713 	notes_attrs = kzalloc(struct_size(notes_attrs, attrs, notes),
1714 			      GFP_KERNEL);
1715 	if (notes_attrs == NULL)
1716 		return;
1717 
1718 	notes_attrs->notes = notes;
1719 	nattr = &notes_attrs->attrs[0];
1720 	for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {
1721 		if (sect_empty(&info->sechdrs[i]))
1722 			continue;
1723 		if (info->sechdrs[i].sh_type == SHT_NOTE) {
1724 			sysfs_bin_attr_init(nattr);
1725 			nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name;
1726 			nattr->attr.mode = S_IRUGO;
1727 			nattr->size = info->sechdrs[i].sh_size;
1728 			nattr->private = (void *) info->sechdrs[i].sh_addr;
1729 			nattr->read = module_notes_read;
1730 			++nattr;
1731 		}
1732 		++loaded;
1733 	}
1734 
1735 	notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
1736 	if (!notes_attrs->dir)
1737 		goto out;
1738 
1739 	for (i = 0; i < notes; ++i)
1740 		if (sysfs_create_bin_file(notes_attrs->dir,
1741 					  &notes_attrs->attrs[i]))
1742 			goto out;
1743 
1744 	mod->notes_attrs = notes_attrs;
1745 	return;
1746 
1747   out:
1748 	free_notes_attrs(notes_attrs, i);
1749 }
1750 
remove_notes_attrs(struct module * mod)1751 static void remove_notes_attrs(struct module *mod)
1752 {
1753 	if (mod->notes_attrs)
1754 		free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
1755 }
1756 
1757 #else
1758 
add_sect_attrs(struct module * mod,const struct load_info * info)1759 static inline void add_sect_attrs(struct module *mod,
1760 				  const struct load_info *info)
1761 {
1762 }
1763 
remove_sect_attrs(struct module * mod)1764 static inline void remove_sect_attrs(struct module *mod)
1765 {
1766 }
1767 
add_notes_attrs(struct module * mod,const struct load_info * info)1768 static inline void add_notes_attrs(struct module *mod,
1769 				   const struct load_info *info)
1770 {
1771 }
1772 
remove_notes_attrs(struct module * mod)1773 static inline void remove_notes_attrs(struct module *mod)
1774 {
1775 }
1776 #endif /* CONFIG_KALLSYMS */
1777 
del_usage_links(struct module * mod)1778 static void del_usage_links(struct module *mod)
1779 {
1780 #ifdef CONFIG_MODULE_UNLOAD
1781 	struct module_use *use;
1782 
1783 	mutex_lock(&module_mutex);
1784 	list_for_each_entry(use, &mod->target_list, target_list)
1785 		sysfs_remove_link(use->target->holders_dir, mod->name);
1786 	mutex_unlock(&module_mutex);
1787 #endif
1788 }
1789 
add_usage_links(struct module * mod)1790 static int add_usage_links(struct module *mod)
1791 {
1792 	int ret = 0;
1793 #ifdef CONFIG_MODULE_UNLOAD
1794 	struct module_use *use;
1795 
1796 	mutex_lock(&module_mutex);
1797 	list_for_each_entry(use, &mod->target_list, target_list) {
1798 		ret = sysfs_create_link(use->target->holders_dir,
1799 					&mod->mkobj.kobj, mod->name);
1800 		if (ret)
1801 			break;
1802 	}
1803 	mutex_unlock(&module_mutex);
1804 	if (ret)
1805 		del_usage_links(mod);
1806 #endif
1807 	return ret;
1808 }
1809 
1810 static void module_remove_modinfo_attrs(struct module *mod, int end);
1811 
module_add_modinfo_attrs(struct module * mod)1812 static int module_add_modinfo_attrs(struct module *mod)
1813 {
1814 	struct module_attribute *attr;
1815 	struct module_attribute *temp_attr;
1816 	int error = 0;
1817 	int i;
1818 
1819 	mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
1820 					(ARRAY_SIZE(modinfo_attrs) + 1)),
1821 					GFP_KERNEL);
1822 	if (!mod->modinfo_attrs)
1823 		return -ENOMEM;
1824 
1825 	temp_attr = mod->modinfo_attrs;
1826 	for (i = 0; (attr = modinfo_attrs[i]); i++) {
1827 		if (!attr->test || attr->test(mod)) {
1828 			memcpy(temp_attr, attr, sizeof(*temp_attr));
1829 			sysfs_attr_init(&temp_attr->attr);
1830 			error = sysfs_create_file(&mod->mkobj.kobj,
1831 					&temp_attr->attr);
1832 			if (error)
1833 				goto error_out;
1834 			++temp_attr;
1835 		}
1836 	}
1837 
1838 	return 0;
1839 
1840 error_out:
1841 	if (i > 0)
1842 		module_remove_modinfo_attrs(mod, --i);
1843 	else
1844 		kfree(mod->modinfo_attrs);
1845 	return error;
1846 }
1847 
module_remove_modinfo_attrs(struct module * mod,int end)1848 static void module_remove_modinfo_attrs(struct module *mod, int end)
1849 {
1850 	struct module_attribute *attr;
1851 	int i;
1852 
1853 	for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
1854 		if (end >= 0 && i > end)
1855 			break;
1856 		/* pick a field to test for end of list */
1857 		if (!attr->attr.name)
1858 			break;
1859 		sysfs_remove_file(&mod->mkobj.kobj, &attr->attr);
1860 		if (attr->free)
1861 			attr->free(mod);
1862 	}
1863 	kfree(mod->modinfo_attrs);
1864 }
1865 
mod_kobject_put(struct module * mod)1866 static void mod_kobject_put(struct module *mod)
1867 {
1868 	DECLARE_COMPLETION_ONSTACK(c);
1869 	mod->mkobj.kobj_completion = &c;
1870 	kobject_put(&mod->mkobj.kobj);
1871 	wait_for_completion(&c);
1872 }
1873 
mod_sysfs_init(struct module * mod)1874 static int mod_sysfs_init(struct module *mod)
1875 {
1876 	int err;
1877 	struct kobject *kobj;
1878 
1879 	if (!module_sysfs_initialized) {
1880 		pr_err("%s: module sysfs not initialized\n", mod->name);
1881 		err = -EINVAL;
1882 		goto out;
1883 	}
1884 
1885 	kobj = kset_find_obj(module_kset, mod->name);
1886 	if (kobj) {
1887 		pr_err("%s: module is already loaded\n", mod->name);
1888 		kobject_put(kobj);
1889 		err = -EINVAL;
1890 		goto out;
1891 	}
1892 
1893 	mod->mkobj.mod = mod;
1894 
1895 	memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
1896 	mod->mkobj.kobj.kset = module_kset;
1897 	err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
1898 				   "%s", mod->name);
1899 	if (err)
1900 		mod_kobject_put(mod);
1901 
1902 out:
1903 	return err;
1904 }
1905 
mod_sysfs_setup(struct module * mod,const struct load_info * info,struct kernel_param * kparam,unsigned int num_params)1906 static int mod_sysfs_setup(struct module *mod,
1907 			   const struct load_info *info,
1908 			   struct kernel_param *kparam,
1909 			   unsigned int num_params)
1910 {
1911 	int err;
1912 
1913 	err = mod_sysfs_init(mod);
1914 	if (err)
1915 		goto out;
1916 
1917 	mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
1918 	if (!mod->holders_dir) {
1919 		err = -ENOMEM;
1920 		goto out_unreg;
1921 	}
1922 
1923 	err = module_param_sysfs_setup(mod, kparam, num_params);
1924 	if (err)
1925 		goto out_unreg_holders;
1926 
1927 	err = module_add_modinfo_attrs(mod);
1928 	if (err)
1929 		goto out_unreg_param;
1930 
1931 	err = add_usage_links(mod);
1932 	if (err)
1933 		goto out_unreg_modinfo_attrs;
1934 
1935 	add_sect_attrs(mod, info);
1936 	add_notes_attrs(mod, info);
1937 
1938 	return 0;
1939 
1940 out_unreg_modinfo_attrs:
1941 	module_remove_modinfo_attrs(mod, -1);
1942 out_unreg_param:
1943 	module_param_sysfs_remove(mod);
1944 out_unreg_holders:
1945 	kobject_put(mod->holders_dir);
1946 out_unreg:
1947 	mod_kobject_put(mod);
1948 out:
1949 	return err;
1950 }
1951 
mod_sysfs_fini(struct module * mod)1952 static void mod_sysfs_fini(struct module *mod)
1953 {
1954 	remove_notes_attrs(mod);
1955 	remove_sect_attrs(mod);
1956 	mod_kobject_put(mod);
1957 }
1958 
init_param_lock(struct module * mod)1959 static void init_param_lock(struct module *mod)
1960 {
1961 	mutex_init(&mod->param_lock);
1962 }
1963 #else /* !CONFIG_SYSFS */
1964 
mod_sysfs_setup(struct module * mod,const struct load_info * info,struct kernel_param * kparam,unsigned int num_params)1965 static int mod_sysfs_setup(struct module *mod,
1966 			   const struct load_info *info,
1967 			   struct kernel_param *kparam,
1968 			   unsigned int num_params)
1969 {
1970 	return 0;
1971 }
1972 
mod_sysfs_fini(struct module * mod)1973 static void mod_sysfs_fini(struct module *mod)
1974 {
1975 }
1976 
module_remove_modinfo_attrs(struct module * mod,int end)1977 static void module_remove_modinfo_attrs(struct module *mod, int end)
1978 {
1979 }
1980 
del_usage_links(struct module * mod)1981 static void del_usage_links(struct module *mod)
1982 {
1983 }
1984 
init_param_lock(struct module * mod)1985 static void init_param_lock(struct module *mod)
1986 {
1987 }
1988 #endif /* CONFIG_SYSFS */
1989 
mod_sysfs_teardown(struct module * mod)1990 static void mod_sysfs_teardown(struct module *mod)
1991 {
1992 	del_usage_links(mod);
1993 	module_remove_modinfo_attrs(mod, -1);
1994 	module_param_sysfs_remove(mod);
1995 	kobject_put(mod->mkobj.drivers_dir);
1996 	kobject_put(mod->holders_dir);
1997 	mod_sysfs_fini(mod);
1998 }
1999 
2000 /*
2001  * LKM RO/NX protection: protect module's text/ro-data
2002  * from modification and any data from execution.
2003  *
2004  * General layout of module is:
2005  *          [text] [read-only-data] [ro-after-init] [writable data]
2006  * text_size -----^                ^               ^               ^
2007  * ro_size ------------------------|               |               |
2008  * ro_after_init_size -----------------------------|               |
2009  * size -----------------------------------------------------------|
2010  *
2011  * These values are always page-aligned (as is base)
2012  */
2013 
2014 /*
2015  * Since some arches are moving towards PAGE_KERNEL module allocations instead
2016  * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the
2017  * CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of
2018  * whether we are strict.
2019  */
2020 #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
frob_text(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))2021 static void frob_text(const struct module_layout *layout,
2022 		      int (*set_memory)(unsigned long start, int num_pages))
2023 {
2024 	BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
2025 	BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1));
2026 	set_memory((unsigned long)layout->base,
2027 		   layout->text_size >> PAGE_SHIFT);
2028 }
2029 
module_enable_x(const struct module * mod)2030 static void module_enable_x(const struct module *mod)
2031 {
2032 	frob_text(&mod->core_layout, set_memory_x);
2033 	frob_text(&mod->init_layout, set_memory_x);
2034 }
2035 #else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
module_enable_x(const struct module * mod)2036 static void module_enable_x(const struct module *mod) { }
2037 #endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
2038 
2039 #ifdef CONFIG_STRICT_MODULE_RWX
frob_rodata(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))2040 static void frob_rodata(const struct module_layout *layout,
2041 			int (*set_memory)(unsigned long start, int num_pages))
2042 {
2043 	BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
2044 	BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1));
2045 	BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
2046 	set_memory((unsigned long)layout->base + layout->text_size,
2047 		   (layout->ro_size - layout->text_size) >> PAGE_SHIFT);
2048 }
2049 
frob_ro_after_init(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))2050 static void frob_ro_after_init(const struct module_layout *layout,
2051 				int (*set_memory)(unsigned long start, int num_pages))
2052 {
2053 	BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
2054 	BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
2055 	BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
2056 	set_memory((unsigned long)layout->base + layout->ro_size,
2057 		   (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT);
2058 }
2059 
frob_writable_data(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))2060 static void frob_writable_data(const struct module_layout *layout,
2061 			       int (*set_memory)(unsigned long start, int num_pages))
2062 {
2063 	BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
2064 	BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
2065 	BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1));
2066 	set_memory((unsigned long)layout->base + layout->ro_after_init_size,
2067 		   (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
2068 }
2069 
module_enable_ro(const struct module * mod,bool after_init)2070 static void module_enable_ro(const struct module *mod, bool after_init)
2071 {
2072 	if (!rodata_enabled)
2073 		return;
2074 
2075 	set_vm_flush_reset_perms(mod->core_layout.base);
2076 	set_vm_flush_reset_perms(mod->init_layout.base);
2077 	frob_text(&mod->core_layout, set_memory_ro);
2078 
2079 	frob_rodata(&mod->core_layout, set_memory_ro);
2080 	frob_text(&mod->init_layout, set_memory_ro);
2081 	frob_rodata(&mod->init_layout, set_memory_ro);
2082 
2083 	if (after_init)
2084 		frob_ro_after_init(&mod->core_layout, set_memory_ro);
2085 }
2086 
module_enable_nx(const struct module * mod)2087 static void module_enable_nx(const struct module *mod)
2088 {
2089 	frob_rodata(&mod->core_layout, set_memory_nx);
2090 	frob_ro_after_init(&mod->core_layout, set_memory_nx);
2091 	frob_writable_data(&mod->core_layout, set_memory_nx);
2092 	frob_rodata(&mod->init_layout, set_memory_nx);
2093 	frob_writable_data(&mod->init_layout, set_memory_nx);
2094 }
2095 
module_enforce_rwx_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)2096 static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
2097 				       char *secstrings, struct module *mod)
2098 {
2099 	const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
2100 	int i;
2101 
2102 	for (i = 0; i < hdr->e_shnum; i++) {
2103 		if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) {
2104 			pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n",
2105 				mod->name, secstrings + sechdrs[i].sh_name, i);
2106 			return -ENOEXEC;
2107 		}
2108 	}
2109 
2110 	return 0;
2111 }
2112 
2113 #else /* !CONFIG_STRICT_MODULE_RWX */
module_enable_nx(const struct module * mod)2114 static void module_enable_nx(const struct module *mod) { }
module_enable_ro(const struct module * mod,bool after_init)2115 static void module_enable_ro(const struct module *mod, bool after_init) {}
module_enforce_rwx_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)2116 static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
2117 				       char *secstrings, struct module *mod)
2118 {
2119 	return 0;
2120 }
2121 #endif /*  CONFIG_STRICT_MODULE_RWX */
2122 
2123 #ifdef CONFIG_LIVEPATCH
2124 /*
2125  * Persist Elf information about a module. Copy the Elf header,
2126  * section header table, section string table, and symtab section
2127  * index from info to mod->klp_info.
2128  */
copy_module_elf(struct module * mod,struct load_info * info)2129 static int copy_module_elf(struct module *mod, struct load_info *info)
2130 {
2131 	unsigned int size, symndx;
2132 	int ret;
2133 
2134 	size = sizeof(*mod->klp_info);
2135 	mod->klp_info = kmalloc(size, GFP_KERNEL);
2136 	if (mod->klp_info == NULL)
2137 		return -ENOMEM;
2138 
2139 	/* Elf header */
2140 	size = sizeof(mod->klp_info->hdr);
2141 	memcpy(&mod->klp_info->hdr, info->hdr, size);
2142 
2143 	/* Elf section header table */
2144 	size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
2145 	mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
2146 	if (mod->klp_info->sechdrs == NULL) {
2147 		ret = -ENOMEM;
2148 		goto free_info;
2149 	}
2150 
2151 	/* Elf section name string table */
2152 	size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
2153 	mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
2154 	if (mod->klp_info->secstrings == NULL) {
2155 		ret = -ENOMEM;
2156 		goto free_sechdrs;
2157 	}
2158 
2159 	/* Elf symbol section index */
2160 	symndx = info->index.sym;
2161 	mod->klp_info->symndx = symndx;
2162 
2163 	/*
2164 	 * For livepatch modules, core_kallsyms.symtab is a complete
2165 	 * copy of the original symbol table. Adjust sh_addr to point
2166 	 * to core_kallsyms.symtab since the copy of the symtab in module
2167 	 * init memory is freed at the end of do_init_module().
2168 	 */
2169 	mod->klp_info->sechdrs[symndx].sh_addr = \
2170 		(unsigned long) mod->core_kallsyms.symtab;
2171 
2172 	return 0;
2173 
2174 free_sechdrs:
2175 	kfree(mod->klp_info->sechdrs);
2176 free_info:
2177 	kfree(mod->klp_info);
2178 	return ret;
2179 }
2180 
free_module_elf(struct module * mod)2181 static void free_module_elf(struct module *mod)
2182 {
2183 	kfree(mod->klp_info->sechdrs);
2184 	kfree(mod->klp_info->secstrings);
2185 	kfree(mod->klp_info);
2186 }
2187 #else /* !CONFIG_LIVEPATCH */
copy_module_elf(struct module * mod,struct load_info * info)2188 static int copy_module_elf(struct module *mod, struct load_info *info)
2189 {
2190 	return 0;
2191 }
2192 
free_module_elf(struct module * mod)2193 static void free_module_elf(struct module *mod)
2194 {
2195 }
2196 #endif /* CONFIG_LIVEPATCH */
2197 
module_memfree(void * module_region)2198 void __weak module_memfree(void *module_region)
2199 {
2200 	/*
2201 	 * This memory may be RO, and freeing RO memory in an interrupt is not
2202 	 * supported by vmalloc.
2203 	 */
2204 	WARN_ON(in_interrupt());
2205 	vfree(module_region);
2206 }
2207 
module_arch_cleanup(struct module * mod)2208 void __weak module_arch_cleanup(struct module *mod)
2209 {
2210 }
2211 
module_arch_freeing_init(struct module * mod)2212 void __weak module_arch_freeing_init(struct module *mod)
2213 {
2214 }
2215 
2216 static void cfi_cleanup(struct module *mod);
2217 
2218 /* Free a module, remove from lists, etc. */
free_module(struct module * mod)2219 static void free_module(struct module *mod)
2220 {
2221 	trace_module_free(mod);
2222 
2223 	mod_sysfs_teardown(mod);
2224 
2225 	/* We leave it in list to prevent duplicate loads, but make sure
2226 	 * that noone uses it while it's being deconstructed. */
2227 	mutex_lock(&module_mutex);
2228 	mod->state = MODULE_STATE_UNFORMED;
2229 	mutex_unlock(&module_mutex);
2230 
2231 	/* Remove dynamic debug info */
2232 	ddebug_remove_module(mod->name);
2233 
2234 	/* Arch-specific cleanup. */
2235 	module_arch_cleanup(mod);
2236 
2237 	/* Module unload stuff */
2238 	module_unload_free(mod);
2239 
2240 	/* Free any allocated parameters. */
2241 	destroy_params(mod->kp, mod->num_kp);
2242 
2243 	if (is_livepatch_module(mod))
2244 		free_module_elf(mod);
2245 
2246 	/* Now we can delete it from the lists */
2247 	mutex_lock(&module_mutex);
2248 	/* Unlink carefully: kallsyms could be walking list. */
2249 	list_del_rcu(&mod->list);
2250 	mod_tree_remove(mod);
2251 	/* Remove this module from bug list, this uses list_del_rcu */
2252 	module_bug_cleanup(mod);
2253 	/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
2254 	synchronize_rcu();
2255 	mutex_unlock(&module_mutex);
2256 
2257 	/* Clean up CFI for the module. */
2258 	cfi_cleanup(mod);
2259 
2260 	/* This may be empty, but that's OK */
2261 	module_arch_freeing_init(mod);
2262 	module_memfree(mod->init_layout.base);
2263 	kfree(mod->args);
2264 	percpu_modfree(mod);
2265 
2266 	/* Free lock-classes; relies on the preceding sync_rcu(). */
2267 	lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
2268 
2269 	/* Finally, free the core (containing the module structure) */
2270 	module_memfree(mod->core_layout.base);
2271 }
2272 
__symbol_get(const char * symbol)2273 void *__symbol_get(const char *symbol)
2274 {
2275 	struct module *owner;
2276 	const struct kernel_symbol *sym;
2277 
2278 	preempt_disable();
2279 	sym = find_symbol(symbol, &owner, NULL, NULL, true, true);
2280 	if (sym && strong_try_module_get(owner))
2281 		sym = NULL;
2282 	preempt_enable();
2283 
2284 	return sym ? (void *)kernel_symbol_value(sym) : NULL;
2285 }
2286 EXPORT_SYMBOL_GPL(__symbol_get);
2287 
2288 /*
2289  * Ensure that an exported symbol [global namespace] does not already exist
2290  * in the kernel or in some other module's exported symbol table.
2291  *
2292  * You must hold the module_mutex.
2293  */
verify_exported_symbols(struct module * mod)2294 static int verify_exported_symbols(struct module *mod)
2295 {
2296 	unsigned int i;
2297 	struct module *owner;
2298 	const struct kernel_symbol *s;
2299 	struct {
2300 		const struct kernel_symbol *sym;
2301 		unsigned int num;
2302 	} arr[] = {
2303 		{ mod->syms, mod->num_syms },
2304 		{ mod->gpl_syms, mod->num_gpl_syms },
2305 		{ mod->gpl_future_syms, mod->num_gpl_future_syms },
2306 #ifdef CONFIG_UNUSED_SYMBOLS
2307 		{ mod->unused_syms, mod->num_unused_syms },
2308 		{ mod->unused_gpl_syms, mod->num_unused_gpl_syms },
2309 #endif
2310 	};
2311 
2312 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
2313 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
2314 			if (find_symbol(kernel_symbol_name(s), &owner, NULL,
2315 					NULL, true, false)) {
2316 				pr_err("%s: exports duplicate symbol %s"
2317 				       " (owned by %s)\n",
2318 				       mod->name, kernel_symbol_name(s),
2319 				       module_name(owner));
2320 				return -ENOEXEC;
2321 			}
2322 		}
2323 	}
2324 	return 0;
2325 }
2326 
ignore_undef_symbol(Elf_Half emachine,const char * name)2327 static bool ignore_undef_symbol(Elf_Half emachine, const char *name)
2328 {
2329 	/*
2330 	 * On x86, PIC code and Clang non-PIC code may have call foo@PLT. GNU as
2331 	 * before 2.37 produces an unreferenced _GLOBAL_OFFSET_TABLE_ on x86-64.
2332 	 * i386 has a similar problem but may not deserve a fix.
2333 	 *
2334 	 * If we ever have to ignore many symbols, consider refactoring the code to
2335 	 * only warn if referenced by a relocation.
2336 	 */
2337 	if (emachine == EM_386 || emachine == EM_X86_64)
2338 		return !strcmp(name, "_GLOBAL_OFFSET_TABLE_");
2339 	return false;
2340 }
2341 
2342 /* Change all symbols so that st_value encodes the pointer directly. */
simplify_symbols(struct module * mod,const struct load_info * info)2343 static int simplify_symbols(struct module *mod, const struct load_info *info)
2344 {
2345 	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
2346 	Elf_Sym *sym = (void *)symsec->sh_addr;
2347 	unsigned long secbase;
2348 	unsigned int i;
2349 	int ret = 0;
2350 	const struct kernel_symbol *ksym;
2351 
2352 	for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
2353 		const char *name = info->strtab + sym[i].st_name;
2354 
2355 		switch (sym[i].st_shndx) {
2356 		case SHN_COMMON:
2357 			/* Ignore common symbols */
2358 			if (!strncmp(name, "__gnu_lto", 9))
2359 				break;
2360 
2361 			/* We compiled with -fno-common.  These are not
2362 			   supposed to happen.  */
2363 			pr_debug("Common symbol: %s\n", name);
2364 			pr_warn("%s: please compile with -fno-common\n",
2365 			       mod->name);
2366 			ret = -ENOEXEC;
2367 			break;
2368 
2369 		case SHN_ABS:
2370 			/* Don't need to do anything */
2371 			pr_debug("Absolute symbol: 0x%08lx\n",
2372 			       (long)sym[i].st_value);
2373 			break;
2374 
2375 		case SHN_LIVEPATCH:
2376 			/* Livepatch symbols are resolved by livepatch */
2377 			break;
2378 
2379 		case SHN_UNDEF:
2380 			ksym = resolve_symbol_wait(mod, info, name);
2381 			/* Ok if resolved.  */
2382 			if (ksym && !IS_ERR(ksym)) {
2383 				sym[i].st_value = kernel_symbol_value(ksym);
2384 				break;
2385 			}
2386 
2387 			/* Ok if weak or ignored.  */
2388 			if (!ksym &&
2389 			    (ELF_ST_BIND(sym[i].st_info) == STB_WEAK ||
2390 			     ignore_undef_symbol(info->hdr->e_machine, name)))
2391 				break;
2392 
2393 			ret = PTR_ERR(ksym) ?: -ENOENT;
2394 			pr_warn("%s: Unknown symbol %s (err %d)\n",
2395 				mod->name, name, ret);
2396 			break;
2397 
2398 		default:
2399 			/* Divert to percpu allocation if a percpu var. */
2400 			if (sym[i].st_shndx == info->index.pcpu)
2401 				secbase = (unsigned long)mod_percpu(mod);
2402 			else
2403 				secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
2404 			sym[i].st_value += secbase;
2405 			break;
2406 		}
2407 	}
2408 
2409 	return ret;
2410 }
2411 
apply_relocations(struct module * mod,const struct load_info * info)2412 static int apply_relocations(struct module *mod, const struct load_info *info)
2413 {
2414 	unsigned int i;
2415 	int err = 0;
2416 
2417 	/* Now do relocations. */
2418 	for (i = 1; i < info->hdr->e_shnum; i++) {
2419 		unsigned int infosec = info->sechdrs[i].sh_info;
2420 
2421 		/* Not a valid relocation section? */
2422 		if (infosec >= info->hdr->e_shnum)
2423 			continue;
2424 
2425 		/* Don't bother with non-allocated sections */
2426 		if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
2427 			continue;
2428 
2429 		if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
2430 			err = klp_apply_section_relocs(mod, info->sechdrs,
2431 						       info->secstrings,
2432 						       info->strtab,
2433 						       info->index.sym, i,
2434 						       NULL);
2435 		else if (info->sechdrs[i].sh_type == SHT_REL)
2436 			err = apply_relocate(info->sechdrs, info->strtab,
2437 					     info->index.sym, i, mod);
2438 		else if (info->sechdrs[i].sh_type == SHT_RELA)
2439 			err = apply_relocate_add(info->sechdrs, info->strtab,
2440 						 info->index.sym, i, mod);
2441 		if (err < 0)
2442 			break;
2443 	}
2444 	return err;
2445 }
2446 
2447 /* Additional bytes needed by arch in front of individual sections */
arch_mod_section_prepend(struct module * mod,unsigned int section)2448 unsigned int __weak arch_mod_section_prepend(struct module *mod,
2449 					     unsigned int section)
2450 {
2451 	/* default implementation just returns zero */
2452 	return 0;
2453 }
2454 
2455 /* Update size with this section: return offset. */
get_offset(struct module * mod,unsigned int * size,Elf_Shdr * sechdr,unsigned int section)2456 static long get_offset(struct module *mod, unsigned int *size,
2457 		       Elf_Shdr *sechdr, unsigned int section)
2458 {
2459 	long ret;
2460 
2461 	*size += arch_mod_section_prepend(mod, section);
2462 	ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
2463 	*size = ret + sechdr->sh_size;
2464 	return ret;
2465 }
2466 
2467 /* Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
2468    might -- code, read-only data, read-write data, small data.  Tally
2469    sizes, and place the offsets into sh_entsize fields: high bit means it
2470    belongs in init. */
layout_sections(struct module * mod,struct load_info * info)2471 static void layout_sections(struct module *mod, struct load_info *info)
2472 {
2473 	static unsigned long const masks[][2] = {
2474 		/* NOTE: all executable code must be the first section
2475 		 * in this array; otherwise modify the text_size
2476 		 * finder in the two loops below */
2477 		{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
2478 		{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
2479 		{ SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
2480 		{ SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
2481 		{ ARCH_SHF_SMALL | SHF_ALLOC, 0 }
2482 	};
2483 	unsigned int m, i;
2484 
2485 	for (i = 0; i < info->hdr->e_shnum; i++)
2486 		info->sechdrs[i].sh_entsize = ~0UL;
2487 
2488 	pr_debug("Core section allocation order:\n");
2489 	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2490 		for (i = 0; i < info->hdr->e_shnum; ++i) {
2491 			Elf_Shdr *s = &info->sechdrs[i];
2492 			const char *sname = info->secstrings + s->sh_name;
2493 
2494 			if ((s->sh_flags & masks[m][0]) != masks[m][0]
2495 			    || (s->sh_flags & masks[m][1])
2496 			    || s->sh_entsize != ~0UL
2497 			    || module_init_section(sname))
2498 				continue;
2499 			s->sh_entsize = get_offset(mod, &mod->core_layout.size, s, i);
2500 			pr_debug("\t%s\n", sname);
2501 		}
2502 		switch (m) {
2503 		case 0: /* executable */
2504 			mod->core_layout.size = debug_align(mod->core_layout.size);
2505 			mod->core_layout.text_size = mod->core_layout.size;
2506 			break;
2507 		case 1: /* RO: text and ro-data */
2508 			mod->core_layout.size = debug_align(mod->core_layout.size);
2509 			mod->core_layout.ro_size = mod->core_layout.size;
2510 			break;
2511 		case 2: /* RO after init */
2512 			mod->core_layout.size = debug_align(mod->core_layout.size);
2513 			mod->core_layout.ro_after_init_size = mod->core_layout.size;
2514 			break;
2515 		case 4: /* whole core */
2516 			mod->core_layout.size = debug_align(mod->core_layout.size);
2517 			break;
2518 		}
2519 	}
2520 
2521 	pr_debug("Init section allocation order:\n");
2522 	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2523 		for (i = 0; i < info->hdr->e_shnum; ++i) {
2524 			Elf_Shdr *s = &info->sechdrs[i];
2525 			const char *sname = info->secstrings + s->sh_name;
2526 
2527 			if ((s->sh_flags & masks[m][0]) != masks[m][0]
2528 			    || (s->sh_flags & masks[m][1])
2529 			    || s->sh_entsize != ~0UL
2530 			    || !module_init_section(sname))
2531 				continue;
2532 			s->sh_entsize = (get_offset(mod, &mod->init_layout.size, s, i)
2533 					 | INIT_OFFSET_MASK);
2534 			pr_debug("\t%s\n", sname);
2535 		}
2536 		switch (m) {
2537 		case 0: /* executable */
2538 			mod->init_layout.size = debug_align(mod->init_layout.size);
2539 			mod->init_layout.text_size = mod->init_layout.size;
2540 			break;
2541 		case 1: /* RO: text and ro-data */
2542 			mod->init_layout.size = debug_align(mod->init_layout.size);
2543 			mod->init_layout.ro_size = mod->init_layout.size;
2544 			break;
2545 		case 2:
2546 			/*
2547 			 * RO after init doesn't apply to init_layout (only
2548 			 * core_layout), so it just takes the value of ro_size.
2549 			 */
2550 			mod->init_layout.ro_after_init_size = mod->init_layout.ro_size;
2551 			break;
2552 		case 4: /* whole init */
2553 			mod->init_layout.size = debug_align(mod->init_layout.size);
2554 			break;
2555 		}
2556 	}
2557 }
2558 
set_license(struct module * mod,const char * license)2559 static void set_license(struct module *mod, const char *license)
2560 {
2561 	if (!license)
2562 		license = "unspecified";
2563 
2564 	if (!license_is_gpl_compatible(license)) {
2565 		if (!test_taint(TAINT_PROPRIETARY_MODULE))
2566 			pr_warn("%s: module license '%s' taints kernel.\n",
2567 				mod->name, license);
2568 		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2569 				 LOCKDEP_NOW_UNRELIABLE);
2570 	}
2571 }
2572 
2573 /* Parse tag=value strings from .modinfo section */
next_string(char * string,unsigned long * secsize)2574 static char *next_string(char *string, unsigned long *secsize)
2575 {
2576 	/* Skip non-zero chars */
2577 	while (string[0]) {
2578 		string++;
2579 		if ((*secsize)-- <= 1)
2580 			return NULL;
2581 	}
2582 
2583 	/* Skip any zero padding. */
2584 	while (!string[0]) {
2585 		string++;
2586 		if ((*secsize)-- <= 1)
2587 			return NULL;
2588 	}
2589 	return string;
2590 }
2591 
get_next_modinfo(const struct load_info * info,const char * tag,char * prev)2592 static char *get_next_modinfo(const struct load_info *info, const char *tag,
2593 			      char *prev)
2594 {
2595 	char *p;
2596 	unsigned int taglen = strlen(tag);
2597 	Elf_Shdr *infosec = &info->sechdrs[info->index.info];
2598 	unsigned long size = infosec->sh_size;
2599 
2600 	/*
2601 	 * get_modinfo() calls made before rewrite_section_headers()
2602 	 * must use sh_offset, as sh_addr isn't set!
2603 	 */
2604 	char *modinfo = (char *)info->hdr + infosec->sh_offset;
2605 
2606 	if (prev) {
2607 		size -= prev - modinfo;
2608 		modinfo = next_string(prev, &size);
2609 	}
2610 
2611 	for (p = modinfo; p; p = next_string(p, &size)) {
2612 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
2613 			return p + taglen + 1;
2614 	}
2615 	return NULL;
2616 }
2617 
get_modinfo(const struct load_info * info,const char * tag)2618 static char *get_modinfo(const struct load_info *info, const char *tag)
2619 {
2620 	return get_next_modinfo(info, tag, NULL);
2621 }
2622 
setup_modinfo(struct module * mod,struct load_info * info)2623 static void setup_modinfo(struct module *mod, struct load_info *info)
2624 {
2625 	struct module_attribute *attr;
2626 	int i;
2627 
2628 	for (i = 0; (attr = modinfo_attrs[i]); i++) {
2629 		if (attr->setup)
2630 			attr->setup(mod, get_modinfo(info, attr->attr.name));
2631 	}
2632 }
2633 
free_modinfo(struct module * mod)2634 static void free_modinfo(struct module *mod)
2635 {
2636 	struct module_attribute *attr;
2637 	int i;
2638 
2639 	for (i = 0; (attr = modinfo_attrs[i]); i++) {
2640 		if (attr->free)
2641 			attr->free(mod);
2642 	}
2643 }
2644 
2645 #ifdef CONFIG_KALLSYMS
2646 
2647 /* Lookup exported symbol in given range of kernel_symbols */
lookup_exported_symbol(const char * name,const struct kernel_symbol * start,const struct kernel_symbol * stop)2648 static const struct kernel_symbol *lookup_exported_symbol(const char *name,
2649 							  const struct kernel_symbol *start,
2650 							  const struct kernel_symbol *stop)
2651 {
2652 	return bsearch(name, start, stop - start,
2653 			sizeof(struct kernel_symbol), cmp_name);
2654 }
2655 
is_exported(const char * name,unsigned long value,const struct module * mod)2656 static int is_exported(const char *name, unsigned long value,
2657 		       const struct module *mod)
2658 {
2659 	const struct kernel_symbol *ks;
2660 	if (!mod)
2661 		ks = lookup_exported_symbol(name, __start___ksymtab, __stop___ksymtab);
2662 	else
2663 		ks = lookup_exported_symbol(name, mod->syms, mod->syms + mod->num_syms);
2664 
2665 	return ks != NULL && kernel_symbol_value(ks) == value;
2666 }
2667 
2668 /* As per nm */
elf_type(const Elf_Sym * sym,const struct load_info * info)2669 static char elf_type(const Elf_Sym *sym, const struct load_info *info)
2670 {
2671 	const Elf_Shdr *sechdrs = info->sechdrs;
2672 
2673 	if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
2674 		if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
2675 			return 'v';
2676 		else
2677 			return 'w';
2678 	}
2679 	if (sym->st_shndx == SHN_UNDEF)
2680 		return 'U';
2681 	if (sym->st_shndx == SHN_ABS || sym->st_shndx == info->index.pcpu)
2682 		return 'a';
2683 	if (sym->st_shndx >= SHN_LORESERVE)
2684 		return '?';
2685 	if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
2686 		return 't';
2687 	if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
2688 	    && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
2689 		if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
2690 			return 'r';
2691 		else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2692 			return 'g';
2693 		else
2694 			return 'd';
2695 	}
2696 	if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
2697 		if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2698 			return 's';
2699 		else
2700 			return 'b';
2701 	}
2702 	if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name,
2703 		      ".debug")) {
2704 		return 'n';
2705 	}
2706 	return '?';
2707 }
2708 
is_core_symbol(const Elf_Sym * src,const Elf_Shdr * sechdrs,unsigned int shnum,unsigned int pcpundx)2709 static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
2710 			unsigned int shnum, unsigned int pcpundx)
2711 {
2712 	const Elf_Shdr *sec;
2713 
2714 	if (src->st_shndx == SHN_UNDEF
2715 	    || src->st_shndx >= shnum
2716 	    || !src->st_name)
2717 		return false;
2718 
2719 #ifdef CONFIG_KALLSYMS_ALL
2720 	if (src->st_shndx == pcpundx)
2721 		return true;
2722 #endif
2723 
2724 	sec = sechdrs + src->st_shndx;
2725 	if (!(sec->sh_flags & SHF_ALLOC)
2726 #ifndef CONFIG_KALLSYMS_ALL
2727 	    || !(sec->sh_flags & SHF_EXECINSTR)
2728 #endif
2729 	    || (sec->sh_entsize & INIT_OFFSET_MASK))
2730 		return false;
2731 
2732 	return true;
2733 }
2734 
2735 /*
2736  * We only allocate and copy the strings needed by the parts of symtab
2737  * we keep.  This is simple, but has the effect of making multiple
2738  * copies of duplicates.  We could be more sophisticated, see
2739  * linux-kernel thread starting with
2740  * <73defb5e4bca04a6431392cc341112b1@localhost>.
2741  */
layout_symtab(struct module * mod,struct load_info * info)2742 static void layout_symtab(struct module *mod, struct load_info *info)
2743 {
2744 	Elf_Shdr *symsect = info->sechdrs + info->index.sym;
2745 	Elf_Shdr *strsect = info->sechdrs + info->index.str;
2746 	const Elf_Sym *src;
2747 	unsigned int i, nsrc, ndst, strtab_size = 0;
2748 
2749 	/* Put symbol section at end of init part of module. */
2750 	symsect->sh_flags |= SHF_ALLOC;
2751 	symsect->sh_entsize = get_offset(mod, &mod->init_layout.size, symsect,
2752 					 info->index.sym) | INIT_OFFSET_MASK;
2753 	pr_debug("\t%s\n", info->secstrings + symsect->sh_name);
2754 
2755 	src = (void *)info->hdr + symsect->sh_offset;
2756 	nsrc = symsect->sh_size / sizeof(*src);
2757 
2758 	/* Compute total space required for the core symbols' strtab. */
2759 	for (ndst = i = 0; i < nsrc; i++) {
2760 		if (i == 0 || is_livepatch_module(mod) ||
2761 		    is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
2762 				   info->index.pcpu)) {
2763 			strtab_size += strlen(&info->strtab[src[i].st_name])+1;
2764 			ndst++;
2765 		}
2766 	}
2767 
2768 	/* Append room for core symbols at end of core part. */
2769 	info->symoffs = ALIGN(mod->core_layout.size, symsect->sh_addralign ?: 1);
2770 	info->stroffs = mod->core_layout.size = info->symoffs + ndst * sizeof(Elf_Sym);
2771 	mod->core_layout.size += strtab_size;
2772 	info->core_typeoffs = mod->core_layout.size;
2773 	mod->core_layout.size += ndst * sizeof(char);
2774 	mod->core_layout.size = debug_align(mod->core_layout.size);
2775 
2776 	/* Put string table section at end of init part of module. */
2777 	strsect->sh_flags |= SHF_ALLOC;
2778 	strsect->sh_entsize = get_offset(mod, &mod->init_layout.size, strsect,
2779 					 info->index.str) | INIT_OFFSET_MASK;
2780 	pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
2781 
2782 	/* We'll tack temporary mod_kallsyms on the end. */
2783 	mod->init_layout.size = ALIGN(mod->init_layout.size,
2784 				      __alignof__(struct mod_kallsyms));
2785 	info->mod_kallsyms_init_off = mod->init_layout.size;
2786 	mod->init_layout.size += sizeof(struct mod_kallsyms);
2787 	info->init_typeoffs = mod->init_layout.size;
2788 	mod->init_layout.size += nsrc * sizeof(char);
2789 	mod->init_layout.size = debug_align(mod->init_layout.size);
2790 }
2791 
2792 /*
2793  * We use the full symtab and strtab which layout_symtab arranged to
2794  * be appended to the init section.  Later we switch to the cut-down
2795  * core-only ones.
2796  */
add_kallsyms(struct module * mod,const struct load_info * info)2797 static void add_kallsyms(struct module *mod, const struct load_info *info)
2798 {
2799 	unsigned int i, ndst;
2800 	const Elf_Sym *src;
2801 	Elf_Sym *dst;
2802 	char *s;
2803 	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
2804 
2805 	/* Set up to point into init section. */
2806 	mod->kallsyms = mod->init_layout.base + info->mod_kallsyms_init_off;
2807 
2808 	mod->kallsyms->symtab = (void *)symsec->sh_addr;
2809 	mod->kallsyms->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
2810 	/* Make sure we get permanent strtab: don't use info->strtab. */
2811 	mod->kallsyms->strtab = (void *)info->sechdrs[info->index.str].sh_addr;
2812 	mod->kallsyms->typetab = mod->init_layout.base + info->init_typeoffs;
2813 
2814 	/*
2815 	 * Now populate the cut down core kallsyms for after init
2816 	 * and set types up while we still have access to sections.
2817 	 */
2818 	mod->core_kallsyms.symtab = dst = mod->core_layout.base + info->symoffs;
2819 	mod->core_kallsyms.strtab = s = mod->core_layout.base + info->stroffs;
2820 	mod->core_kallsyms.typetab = mod->core_layout.base + info->core_typeoffs;
2821 	src = mod->kallsyms->symtab;
2822 	for (ndst = i = 0; i < mod->kallsyms->num_symtab; i++) {
2823 		mod->kallsyms->typetab[i] = elf_type(src + i, info);
2824 		if (i == 0 || is_livepatch_module(mod) ||
2825 		    is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
2826 				   info->index.pcpu)) {
2827 			mod->core_kallsyms.typetab[ndst] =
2828 			    mod->kallsyms->typetab[i];
2829 			dst[ndst] = src[i];
2830 			dst[ndst++].st_name = s - mod->core_kallsyms.strtab;
2831 			s += strlcpy(s, &mod->kallsyms->strtab[src[i].st_name],
2832 				     KSYM_NAME_LEN) + 1;
2833 		}
2834 	}
2835 	mod->core_kallsyms.num_symtab = ndst;
2836 }
2837 #else
layout_symtab(struct module * mod,struct load_info * info)2838 static inline void layout_symtab(struct module *mod, struct load_info *info)
2839 {
2840 }
2841 
add_kallsyms(struct module * mod,const struct load_info * info)2842 static void add_kallsyms(struct module *mod, const struct load_info *info)
2843 {
2844 }
2845 #endif /* CONFIG_KALLSYMS */
2846 
dynamic_debug_setup(struct module * mod,struct _ddebug * debug,unsigned int num)2847 static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)
2848 {
2849 	if (!debug)
2850 		return;
2851 	ddebug_add_module(debug, num, mod->name);
2852 }
2853 
dynamic_debug_remove(struct module * mod,struct _ddebug * debug)2854 static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)
2855 {
2856 	if (debug)
2857 		ddebug_remove_module(mod->name);
2858 }
2859 
module_alloc(unsigned long size)2860 void * __weak module_alloc(unsigned long size)
2861 {
2862 	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
2863 			GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
2864 			NUMA_NO_NODE, __builtin_return_address(0));
2865 }
2866 
module_init_section(const char * name)2867 bool __weak module_init_section(const char *name)
2868 {
2869 	return strstarts(name, ".init");
2870 }
2871 
module_exit_section(const char * name)2872 bool __weak module_exit_section(const char *name)
2873 {
2874 	return strstarts(name, ".exit");
2875 }
2876 
2877 #ifdef CONFIG_DEBUG_KMEMLEAK
kmemleak_load_module(const struct module * mod,const struct load_info * info)2878 static void kmemleak_load_module(const struct module *mod,
2879 				 const struct load_info *info)
2880 {
2881 	unsigned int i;
2882 
2883 	/* only scan the sections containing data */
2884 	kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
2885 
2886 	for (i = 1; i < info->hdr->e_shnum; i++) {
2887 		/* Scan all writable sections that's not executable */
2888 		if (!(info->sechdrs[i].sh_flags & SHF_ALLOC) ||
2889 		    !(info->sechdrs[i].sh_flags & SHF_WRITE) ||
2890 		    (info->sechdrs[i].sh_flags & SHF_EXECINSTR))
2891 			continue;
2892 
2893 		kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
2894 				   info->sechdrs[i].sh_size, GFP_KERNEL);
2895 	}
2896 }
2897 #else
kmemleak_load_module(const struct module * mod,const struct load_info * info)2898 static inline void kmemleak_load_module(const struct module *mod,
2899 					const struct load_info *info)
2900 {
2901 }
2902 #endif
2903 
2904 #ifdef CONFIG_MODULE_SIG
module_sig_check(struct load_info * info,int flags)2905 static int module_sig_check(struct load_info *info, int flags)
2906 {
2907 	int err = -ENODATA;
2908 	const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
2909 	const char *reason;
2910 	const void *mod = info->hdr;
2911 
2912 	/*
2913 	 * Require flags == 0, as a module with version information
2914 	 * removed is no longer the module that was signed
2915 	 */
2916 	if (flags == 0 &&
2917 	    info->len > markerlen &&
2918 	    memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
2919 		/* We truncate the module to discard the signature */
2920 		info->len -= markerlen;
2921 		err = mod_verify_sig(mod, info);
2922 	}
2923 
2924 	switch (err) {
2925 	case 0:
2926 		info->sig_ok = true;
2927 		return 0;
2928 
2929 		/* We don't permit modules to be loaded into trusted kernels
2930 		 * without a valid signature on them, but if we're not
2931 		 * enforcing, certain errors are non-fatal.
2932 		 */
2933 	case -ENODATA:
2934 		reason = "unsigned module";
2935 		break;
2936 	case -ENOPKG:
2937 		reason = "module with unsupported crypto";
2938 		break;
2939 	case -ENOKEY:
2940 		reason = "module with unavailable key";
2941 		break;
2942 
2943 		/* All other errors are fatal, including nomem, unparseable
2944 		 * signatures and signature check failures - even if signatures
2945 		 * aren't required.
2946 		 */
2947 	default:
2948 		return err;
2949 	}
2950 
2951 	if (is_module_sig_enforced()) {
2952 		pr_notice("Loading of %s is rejected\n", reason);
2953 		return -EKEYREJECTED;
2954 	}
2955 
2956 	return security_locked_down(LOCKDOWN_MODULE_SIGNATURE);
2957 }
2958 #else /* !CONFIG_MODULE_SIG */
module_sig_check(struct load_info * info,int flags)2959 static int module_sig_check(struct load_info *info, int flags)
2960 {
2961 	return 0;
2962 }
2963 #endif /* !CONFIG_MODULE_SIG */
2964 
validate_section_offset(struct load_info * info,Elf_Shdr * shdr)2965 static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
2966 {
2967 	unsigned long secend;
2968 
2969 	/*
2970 	 * Check for both overflow and offset/size being
2971 	 * too large.
2972 	 */
2973 	secend = shdr->sh_offset + shdr->sh_size;
2974 	if (secend < shdr->sh_offset || secend > info->len)
2975 		return -ENOEXEC;
2976 
2977 	return 0;
2978 }
2979 
2980 /*
2981  * Sanity checks against invalid binaries, wrong arch, weird elf version.
2982  *
2983  * Also do basic validity checks against section offsets and sizes, the
2984  * section name string table, and the indices used for it (sh_name).
2985  */
elf_validity_check(struct load_info * info)2986 static int elf_validity_check(struct load_info *info)
2987 {
2988 	unsigned int i;
2989 	Elf_Shdr *shdr, *strhdr;
2990 	int err;
2991 
2992 	if (info->len < sizeof(*(info->hdr)))
2993 		return -ENOEXEC;
2994 
2995 	if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0
2996 	    || info->hdr->e_type != ET_REL
2997 	    || !elf_check_arch(info->hdr)
2998 	    || info->hdr->e_shentsize != sizeof(Elf_Shdr))
2999 		return -ENOEXEC;
3000 
3001 	/*
3002 	 * e_shnum is 16 bits, and sizeof(Elf_Shdr) is
3003 	 * known and small. So e_shnum * sizeof(Elf_Shdr)
3004 	 * will not overflow unsigned long on any platform.
3005 	 */
3006 	if (info->hdr->e_shoff >= info->len
3007 	    || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
3008 		info->len - info->hdr->e_shoff))
3009 		return -ENOEXEC;
3010 
3011 	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
3012 
3013 	/*
3014 	 * Verify if the section name table index is valid.
3015 	 */
3016 	if (info->hdr->e_shstrndx == SHN_UNDEF
3017 	    || info->hdr->e_shstrndx >= info->hdr->e_shnum)
3018 		return -ENOEXEC;
3019 
3020 	strhdr = &info->sechdrs[info->hdr->e_shstrndx];
3021 	err = validate_section_offset(info, strhdr);
3022 	if (err < 0)
3023 		return err;
3024 
3025 	/*
3026 	 * The section name table must be NUL-terminated, as required
3027 	 * by the spec. This makes strcmp and pr_* calls that access
3028 	 * strings in the section safe.
3029 	 */
3030 	info->secstrings = (void *)info->hdr + strhdr->sh_offset;
3031 	if (info->secstrings[strhdr->sh_size - 1] != '\0')
3032 		return -ENOEXEC;
3033 
3034 	/*
3035 	 * The code assumes that section 0 has a length of zero and
3036 	 * an addr of zero, so check for it.
3037 	 */
3038 	if (info->sechdrs[0].sh_type != SHT_NULL
3039 	    || info->sechdrs[0].sh_size != 0
3040 	    || info->sechdrs[0].sh_addr != 0)
3041 		return -ENOEXEC;
3042 
3043 	for (i = 1; i < info->hdr->e_shnum; i++) {
3044 		shdr = &info->sechdrs[i];
3045 		switch (shdr->sh_type) {
3046 		case SHT_NULL:
3047 		case SHT_NOBITS:
3048 			continue;
3049 		case SHT_SYMTAB:
3050 			if (shdr->sh_link == SHN_UNDEF
3051 			    || shdr->sh_link >= info->hdr->e_shnum)
3052 				return -ENOEXEC;
3053 			fallthrough;
3054 		default:
3055 			err = validate_section_offset(info, shdr);
3056 			if (err < 0) {
3057 				pr_err("Invalid ELF section in module (section %u type %u)\n",
3058 					i, shdr->sh_type);
3059 				return err;
3060 			}
3061 
3062 			if (shdr->sh_flags & SHF_ALLOC) {
3063 				if (shdr->sh_name >= strhdr->sh_size) {
3064 					pr_err("Invalid ELF section name in module (section %u type %u)\n",
3065 					       i, shdr->sh_type);
3066 					return -ENOEXEC;
3067 				}
3068 			}
3069 			break;
3070 		}
3071 	}
3072 
3073 	return 0;
3074 }
3075 
3076 #define COPY_CHUNK_SIZE (16*PAGE_SIZE)
3077 
copy_chunked_from_user(void * dst,const void __user * usrc,unsigned long len)3078 static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned long len)
3079 {
3080 	do {
3081 		unsigned long n = min(len, COPY_CHUNK_SIZE);
3082 
3083 		if (copy_from_user(dst, usrc, n) != 0)
3084 			return -EFAULT;
3085 		cond_resched();
3086 		dst += n;
3087 		usrc += n;
3088 		len -= n;
3089 	} while (len);
3090 	return 0;
3091 }
3092 
3093 #ifdef CONFIG_LIVEPATCH
check_modinfo_livepatch(struct module * mod,struct load_info * info)3094 static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
3095 {
3096 	if (get_modinfo(info, "livepatch")) {
3097 		mod->klp = true;
3098 		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
3099 		pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
3100 			       mod->name);
3101 	}
3102 
3103 	return 0;
3104 }
3105 #else /* !CONFIG_LIVEPATCH */
check_modinfo_livepatch(struct module * mod,struct load_info * info)3106 static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
3107 {
3108 	if (get_modinfo(info, "livepatch")) {
3109 		pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
3110 		       mod->name);
3111 		return -ENOEXEC;
3112 	}
3113 
3114 	return 0;
3115 }
3116 #endif /* CONFIG_LIVEPATCH */
3117 
check_modinfo_retpoline(struct module * mod,struct load_info * info)3118 static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
3119 {
3120 	if (retpoline_module_ok(get_modinfo(info, "retpoline")))
3121 		return;
3122 
3123 	pr_warn("%s: loading module not compiled with retpoline compiler.\n",
3124 		mod->name);
3125 }
3126 
3127 /* Sets info->hdr and info->len. */
copy_module_from_user(const void __user * umod,unsigned long len,struct load_info * info)3128 static int copy_module_from_user(const void __user *umod, unsigned long len,
3129 				  struct load_info *info)
3130 {
3131 	int err;
3132 
3133 	info->len = len;
3134 	if (info->len < sizeof(*(info->hdr)))
3135 		return -ENOEXEC;
3136 
3137 	err = security_kernel_load_data(LOADING_MODULE, true);
3138 	if (err)
3139 		return err;
3140 
3141 	/* Suck in entire file: we'll want most of it. */
3142 	info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN);
3143 	if (!info->hdr)
3144 		return -ENOMEM;
3145 
3146 	if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) {
3147 		err = -EFAULT;
3148 		goto out;
3149 	}
3150 
3151 	err = security_kernel_post_load_data((char *)info->hdr, info->len,
3152 					     LOADING_MODULE, "init_module");
3153 out:
3154 	if (err)
3155 		vfree(info->hdr);
3156 
3157 	return err;
3158 }
3159 
free_copy(struct load_info * info)3160 static void free_copy(struct load_info *info)
3161 {
3162 	vfree(info->hdr);
3163 }
3164 
rewrite_section_headers(struct load_info * info,int flags)3165 static int rewrite_section_headers(struct load_info *info, int flags)
3166 {
3167 	unsigned int i;
3168 
3169 	/* This should always be true, but let's be sure. */
3170 	info->sechdrs[0].sh_addr = 0;
3171 
3172 	for (i = 1; i < info->hdr->e_shnum; i++) {
3173 		Elf_Shdr *shdr = &info->sechdrs[i];
3174 
3175 		/* Mark all sections sh_addr with their address in the
3176 		   temporary image. */
3177 		shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
3178 
3179 #ifndef CONFIG_MODULE_UNLOAD
3180 		/* Don't load .exit sections */
3181 		if (module_exit_section(info->secstrings+shdr->sh_name))
3182 			shdr->sh_flags &= ~(unsigned long)SHF_ALLOC;
3183 #endif
3184 	}
3185 
3186 	/* Track but don't keep modinfo and version sections. */
3187 	info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
3188 	info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
3189 
3190 	return 0;
3191 }
3192 
3193 /*
3194  * Set up our basic convenience variables (pointers to section headers,
3195  * search for module section index etc), and do some basic section
3196  * verification.
3197  *
3198  * Set info->mod to the temporary copy of the module in info->hdr. The final one
3199  * will be allocated in move_module().
3200  */
setup_load_info(struct load_info * info,int flags)3201 static int setup_load_info(struct load_info *info, int flags)
3202 {
3203 	unsigned int i;
3204 
3205 	/* Try to find a name early so we can log errors with a module name */
3206 	info->index.info = find_sec(info, ".modinfo");
3207 	if (info->index.info)
3208 		info->name = get_modinfo(info, "name");
3209 
3210 	/* Find internal symbols and strings. */
3211 	for (i = 1; i < info->hdr->e_shnum; i++) {
3212 		if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
3213 			info->index.sym = i;
3214 			info->index.str = info->sechdrs[i].sh_link;
3215 			info->strtab = (char *)info->hdr
3216 				+ info->sechdrs[info->index.str].sh_offset;
3217 			break;
3218 		}
3219 	}
3220 
3221 	if (info->index.sym == 0) {
3222 		pr_warn("%s: module has no symbols (stripped?)\n",
3223 			info->name ?: "(missing .modinfo section or name field)");
3224 		return -ENOEXEC;
3225 	}
3226 
3227 	info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
3228 	if (!info->index.mod) {
3229 		pr_warn("%s: No module found in object\n",
3230 			info->name ?: "(missing .modinfo section or name field)");
3231 		return -ENOEXEC;
3232 	}
3233 	/* This is temporary: point mod into copy of data. */
3234 	info->mod = (void *)info->hdr + info->sechdrs[info->index.mod].sh_offset;
3235 
3236 	/*
3237 	 * If we didn't load the .modinfo 'name' field earlier, fall back to
3238 	 * on-disk struct mod 'name' field.
3239 	 */
3240 	if (!info->name)
3241 		info->name = info->mod->name;
3242 
3243 	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
3244 		info->index.vers = 0; /* Pretend no __versions section! */
3245 	else
3246 		info->index.vers = find_sec(info, "__versions");
3247 
3248 	info->index.pcpu = find_pcpusec(info);
3249 
3250 	return 0;
3251 }
3252 
check_modinfo(struct module * mod,struct load_info * info,int flags)3253 static int check_modinfo(struct module *mod, struct load_info *info, int flags)
3254 {
3255 	const char *modmagic = get_modinfo(info, "vermagic");
3256 	int err;
3257 
3258 	if (flags & MODULE_INIT_IGNORE_VERMAGIC)
3259 		modmagic = NULL;
3260 
3261 	/* This is allowed: modprobe --force will invalidate it. */
3262 	if (!modmagic) {
3263 		err = try_to_force_load(mod, "bad vermagic");
3264 		if (err)
3265 			return err;
3266 	} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
3267 		pr_err("%s: version magic '%s' should be '%s'\n",
3268 		       info->name, modmagic, vermagic);
3269 		return -ENOEXEC;
3270 	}
3271 
3272 	if (!get_modinfo(info, "intree")) {
3273 		if (!test_taint(TAINT_OOT_MODULE))
3274 			pr_warn("%s: loading out-of-tree module taints kernel.\n",
3275 				mod->name);
3276 		add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
3277 	}
3278 
3279 	check_modinfo_retpoline(mod, info);
3280 
3281 	if (get_modinfo(info, "staging")) {
3282 		add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
3283 		pr_warn("%s: module is from the staging directory, the quality "
3284 			"is unknown, you have been warned.\n", mod->name);
3285 	}
3286 
3287 	err = check_modinfo_livepatch(mod, info);
3288 	if (err)
3289 		return err;
3290 
3291 	/* Set up license info based on the info section */
3292 	set_license(mod, get_modinfo(info, "license"));
3293 
3294 	return 0;
3295 }
3296 
find_module_sections(struct module * mod,struct load_info * info)3297 static int find_module_sections(struct module *mod, struct load_info *info)
3298 {
3299 	mod->kp = section_objs(info, "__param",
3300 			       sizeof(*mod->kp), &mod->num_kp);
3301 	mod->syms = section_objs(info, "__ksymtab",
3302 				 sizeof(*mod->syms), &mod->num_syms);
3303 	mod->crcs = section_addr(info, "__kcrctab");
3304 	mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
3305 				     sizeof(*mod->gpl_syms),
3306 				     &mod->num_gpl_syms);
3307 	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
3308 	mod->gpl_future_syms = section_objs(info,
3309 					    "__ksymtab_gpl_future",
3310 					    sizeof(*mod->gpl_future_syms),
3311 					    &mod->num_gpl_future_syms);
3312 	mod->gpl_future_crcs = section_addr(info, "__kcrctab_gpl_future");
3313 
3314 #ifdef CONFIG_UNUSED_SYMBOLS
3315 	mod->unused_syms = section_objs(info, "__ksymtab_unused",
3316 					sizeof(*mod->unused_syms),
3317 					&mod->num_unused_syms);
3318 	mod->unused_crcs = section_addr(info, "__kcrctab_unused");
3319 	mod->unused_gpl_syms = section_objs(info, "__ksymtab_unused_gpl",
3320 					    sizeof(*mod->unused_gpl_syms),
3321 					    &mod->num_unused_gpl_syms);
3322 	mod->unused_gpl_crcs = section_addr(info, "__kcrctab_unused_gpl");
3323 #endif
3324 #ifdef CONFIG_CONSTRUCTORS
3325 	mod->ctors = section_objs(info, ".ctors",
3326 				  sizeof(*mod->ctors), &mod->num_ctors);
3327 	if (!mod->ctors)
3328 		mod->ctors = section_objs(info, ".init_array",
3329 				sizeof(*mod->ctors), &mod->num_ctors);
3330 	else if (find_sec(info, ".init_array")) {
3331 		/*
3332 		 * This shouldn't happen with same compiler and binutils
3333 		 * building all parts of the module.
3334 		 */
3335 		pr_warn("%s: has both .ctors and .init_array.\n",
3336 		       mod->name);
3337 		return -EINVAL;
3338 	}
3339 #endif
3340 
3341 	mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
3342 						&mod->noinstr_text_size);
3343 
3344 #ifdef CONFIG_TRACEPOINTS
3345 	mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
3346 					     sizeof(*mod->tracepoints_ptrs),
3347 					     &mod->num_tracepoints);
3348 #endif
3349 #ifdef CONFIG_TREE_SRCU
3350 	mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs",
3351 					     sizeof(*mod->srcu_struct_ptrs),
3352 					     &mod->num_srcu_structs);
3353 #endif
3354 #ifdef CONFIG_BPF_EVENTS
3355 	mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map",
3356 					   sizeof(*mod->bpf_raw_events),
3357 					   &mod->num_bpf_raw_events);
3358 #endif
3359 #ifdef CONFIG_JUMP_LABEL
3360 	mod->jump_entries = section_objs(info, "__jump_table",
3361 					sizeof(*mod->jump_entries),
3362 					&mod->num_jump_entries);
3363 #endif
3364 #ifdef CONFIG_EVENT_TRACING
3365 	mod->trace_events = section_objs(info, "_ftrace_events",
3366 					 sizeof(*mod->trace_events),
3367 					 &mod->num_trace_events);
3368 	mod->trace_evals = section_objs(info, "_ftrace_eval_map",
3369 					sizeof(*mod->trace_evals),
3370 					&mod->num_trace_evals);
3371 #endif
3372 #ifdef CONFIG_TRACING
3373 	mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
3374 					 sizeof(*mod->trace_bprintk_fmt_start),
3375 					 &mod->num_trace_bprintk_fmt);
3376 #endif
3377 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
3378 	/* sechdrs[0].sh_size is always zero */
3379 	mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
3380 					     sizeof(*mod->ftrace_callsites),
3381 					     &mod->num_ftrace_callsites);
3382 #endif
3383 #ifdef CONFIG_FUNCTION_ERROR_INJECTION
3384 	mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
3385 					    sizeof(*mod->ei_funcs),
3386 					    &mod->num_ei_funcs);
3387 #endif
3388 #ifdef CONFIG_KPROBES
3389 	mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
3390 						&mod->kprobes_text_size);
3391 	mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
3392 						sizeof(unsigned long),
3393 						&mod->num_kprobe_blacklist);
3394 #endif
3395 #ifdef CONFIG_HAVE_STATIC_CALL_INLINE
3396 	mod->static_call_sites = section_objs(info, ".static_call_sites",
3397 					      sizeof(*mod->static_call_sites),
3398 					      &mod->num_static_call_sites);
3399 #endif
3400 	mod->extable = section_objs(info, "__ex_table",
3401 				    sizeof(*mod->extable), &mod->num_exentries);
3402 
3403 	if (section_addr(info, "__obsparm"))
3404 		pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
3405 
3406 	info->debug = section_objs(info, "__dyndbg",
3407 				   sizeof(*info->debug), &info->num_debug);
3408 
3409 	return 0;
3410 }
3411 
move_module(struct module * mod,struct load_info * info)3412 static int move_module(struct module *mod, struct load_info *info)
3413 {
3414 	int i;
3415 	void *ptr;
3416 
3417 	/* Do the allocs. */
3418 	ptr = module_alloc(mod->core_layout.size);
3419 	/*
3420 	 * The pointer to this block is stored in the module structure
3421 	 * which is inside the block. Just mark it as not being a
3422 	 * leak.
3423 	 */
3424 	kmemleak_not_leak(ptr);
3425 	if (!ptr)
3426 		return -ENOMEM;
3427 
3428 	memset(ptr, 0, mod->core_layout.size);
3429 	mod->core_layout.base = ptr;
3430 
3431 	if (mod->init_layout.size) {
3432 		ptr = module_alloc(mod->init_layout.size);
3433 		/*
3434 		 * The pointer to this block is stored in the module structure
3435 		 * which is inside the block. This block doesn't need to be
3436 		 * scanned as it contains data and code that will be freed
3437 		 * after the module is initialized.
3438 		 */
3439 		kmemleak_ignore(ptr);
3440 		if (!ptr) {
3441 			module_memfree(mod->core_layout.base);
3442 			return -ENOMEM;
3443 		}
3444 		memset(ptr, 0, mod->init_layout.size);
3445 		mod->init_layout.base = ptr;
3446 	} else
3447 		mod->init_layout.base = NULL;
3448 
3449 	/* Transfer each section which specifies SHF_ALLOC */
3450 	pr_debug("final section addresses:\n");
3451 	for (i = 0; i < info->hdr->e_shnum; i++) {
3452 		void *dest;
3453 		Elf_Shdr *shdr = &info->sechdrs[i];
3454 
3455 		if (!(shdr->sh_flags & SHF_ALLOC))
3456 			continue;
3457 
3458 		if (shdr->sh_entsize & INIT_OFFSET_MASK)
3459 			dest = mod->init_layout.base
3460 				+ (shdr->sh_entsize & ~INIT_OFFSET_MASK);
3461 		else
3462 			dest = mod->core_layout.base + shdr->sh_entsize;
3463 
3464 		if (shdr->sh_type != SHT_NOBITS)
3465 			memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
3466 		/* Update sh_addr to point to copy in image. */
3467 		shdr->sh_addr = (unsigned long)dest;
3468 		pr_debug("\t0x%lx %s\n",
3469 			 (long)shdr->sh_addr, info->secstrings + shdr->sh_name);
3470 	}
3471 
3472 	return 0;
3473 }
3474 
check_module_license_and_versions(struct module * mod)3475 static int check_module_license_and_versions(struct module *mod)
3476 {
3477 	int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE);
3478 
3479 	/*
3480 	 * ndiswrapper is under GPL by itself, but loads proprietary modules.
3481 	 * Don't use add_taint_module(), as it would prevent ndiswrapper from
3482 	 * using GPL-only symbols it needs.
3483 	 */
3484 	if (strcmp(mod->name, "ndiswrapper") == 0)
3485 		add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
3486 
3487 	/* driverloader was caught wrongly pretending to be under GPL */
3488 	if (strcmp(mod->name, "driverloader") == 0)
3489 		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
3490 				 LOCKDEP_NOW_UNRELIABLE);
3491 
3492 	/* lve claims to be GPL but upstream won't provide source */
3493 	if (strcmp(mod->name, "lve") == 0)
3494 		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
3495 				 LOCKDEP_NOW_UNRELIABLE);
3496 
3497 	if (!prev_taint && test_taint(TAINT_PROPRIETARY_MODULE))
3498 		pr_warn("%s: module license taints kernel.\n", mod->name);
3499 
3500 #ifdef CONFIG_MODVERSIONS
3501 	if ((mod->num_syms && !mod->crcs)
3502 	    || (mod->num_gpl_syms && !mod->gpl_crcs)
3503 	    || (mod->num_gpl_future_syms && !mod->gpl_future_crcs)
3504 #ifdef CONFIG_UNUSED_SYMBOLS
3505 	    || (mod->num_unused_syms && !mod->unused_crcs)
3506 	    || (mod->num_unused_gpl_syms && !mod->unused_gpl_crcs)
3507 #endif
3508 		) {
3509 		return try_to_force_load(mod,
3510 					 "no versions for exported symbols");
3511 	}
3512 #endif
3513 	return 0;
3514 }
3515 
flush_module_icache(const struct module * mod)3516 static void flush_module_icache(const struct module *mod)
3517 {
3518 	/*
3519 	 * Flush the instruction cache, since we've played with text.
3520 	 * Do it before processing of module parameters, so the module
3521 	 * can provide parameter accessor functions of its own.
3522 	 */
3523 	if (mod->init_layout.base)
3524 		flush_icache_range((unsigned long)mod->init_layout.base,
3525 				   (unsigned long)mod->init_layout.base
3526 				   + mod->init_layout.size);
3527 	flush_icache_range((unsigned long)mod->core_layout.base,
3528 			   (unsigned long)mod->core_layout.base + mod->core_layout.size);
3529 }
3530 
module_frob_arch_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)3531 int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
3532 				     Elf_Shdr *sechdrs,
3533 				     char *secstrings,
3534 				     struct module *mod)
3535 {
3536 	return 0;
3537 }
3538 
3539 /* module_blacklist is a comma-separated list of module names */
3540 static char *module_blacklist;
blacklisted(const char * module_name)3541 static bool blacklisted(const char *module_name)
3542 {
3543 	const char *p;
3544 	size_t len;
3545 
3546 	if (!module_blacklist)
3547 		return false;
3548 
3549 	for (p = module_blacklist; *p; p += len) {
3550 		len = strcspn(p, ",");
3551 		if (strlen(module_name) == len && !memcmp(module_name, p, len))
3552 			return true;
3553 		if (p[len] == ',')
3554 			len++;
3555 	}
3556 	return false;
3557 }
3558 core_param(module_blacklist, module_blacklist, charp, 0400);
3559 
layout_and_allocate(struct load_info * info,int flags)3560 static struct module *layout_and_allocate(struct load_info *info, int flags)
3561 {
3562 	struct module *mod;
3563 	unsigned int ndx;
3564 	int err;
3565 
3566 	err = check_modinfo(info->mod, info, flags);
3567 	if (err)
3568 		return ERR_PTR(err);
3569 
3570 	/* Allow arches to frob section contents and sizes.  */
3571 	err = module_frob_arch_sections(info->hdr, info->sechdrs,
3572 					info->secstrings, info->mod);
3573 	if (err < 0)
3574 		return ERR_PTR(err);
3575 
3576 	err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
3577 					  info->secstrings, info->mod);
3578 	if (err < 0)
3579 		return ERR_PTR(err);
3580 
3581 	/* We will do a special allocation for per-cpu sections later. */
3582 	info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
3583 
3584 	/*
3585 	 * Mark ro_after_init section with SHF_RO_AFTER_INIT so that
3586 	 * layout_sections() can put it in the right place.
3587 	 * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
3588 	 */
3589 	ndx = find_sec(info, ".data..ro_after_init");
3590 	if (ndx)
3591 		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
3592 	/*
3593 	 * Mark the __jump_table section as ro_after_init as well: these data
3594 	 * structures are never modified, with the exception of entries that
3595 	 * refer to code in the __init section, which are annotated as such
3596 	 * at module load time.
3597 	 */
3598 	ndx = find_sec(info, "__jump_table");
3599 	if (ndx)
3600 		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
3601 
3602 	/* Determine total sizes, and put offsets in sh_entsize.  For now
3603 	   this is done generically; there doesn't appear to be any
3604 	   special cases for the architectures. */
3605 	layout_sections(info->mod, info);
3606 	layout_symtab(info->mod, info);
3607 
3608 	/* Allocate and move to the final place */
3609 	err = move_module(info->mod, info);
3610 	if (err)
3611 		return ERR_PTR(err);
3612 
3613 	/* Module has been copied to its final place now: return it. */
3614 	mod = (void *)info->sechdrs[info->index.mod].sh_addr;
3615 	kmemleak_load_module(mod, info);
3616 	return mod;
3617 }
3618 
3619 /* mod is no longer valid after this! */
module_deallocate(struct module * mod,struct load_info * info)3620 static void module_deallocate(struct module *mod, struct load_info *info)
3621 {
3622 	percpu_modfree(mod);
3623 	module_arch_freeing_init(mod);
3624 	module_memfree(mod->init_layout.base);
3625 	module_memfree(mod->core_layout.base);
3626 }
3627 
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)3628 int __weak module_finalize(const Elf_Ehdr *hdr,
3629 			   const Elf_Shdr *sechdrs,
3630 			   struct module *me)
3631 {
3632 	return 0;
3633 }
3634 
post_relocation(struct module * mod,const struct load_info * info)3635 static int post_relocation(struct module *mod, const struct load_info *info)
3636 {
3637 	/* Sort exception table now relocations are done. */
3638 	sort_extable(mod->extable, mod->extable + mod->num_exentries);
3639 
3640 	/* Copy relocated percpu area over. */
3641 	percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
3642 		       info->sechdrs[info->index.pcpu].sh_size);
3643 
3644 	/* Setup kallsyms-specific fields. */
3645 	add_kallsyms(mod, info);
3646 
3647 	/* Arch-specific module finalizing. */
3648 	return module_finalize(info->hdr, info->sechdrs, mod);
3649 }
3650 
3651 /* Is this module of this name done loading?  No locks held. */
finished_loading(const char * name)3652 static bool finished_loading(const char *name)
3653 {
3654 	struct module *mod;
3655 	bool ret;
3656 
3657 	/*
3658 	 * The module_mutex should not be a heavily contended lock;
3659 	 * if we get the occasional sleep here, we'll go an extra iteration
3660 	 * in the wait_event_interruptible(), which is harmless.
3661 	 */
3662 	sched_annotate_sleep();
3663 	mutex_lock(&module_mutex);
3664 	mod = find_module_all(name, strlen(name), true);
3665 	ret = !mod || mod->state == MODULE_STATE_LIVE;
3666 	mutex_unlock(&module_mutex);
3667 
3668 	return ret;
3669 }
3670 
3671 /* Call module constructors. */
do_mod_ctors(struct module * mod)3672 static void do_mod_ctors(struct module *mod)
3673 {
3674 #ifdef CONFIG_CONSTRUCTORS
3675 	unsigned long i;
3676 
3677 	for (i = 0; i < mod->num_ctors; i++)
3678 		mod->ctors[i]();
3679 #endif
3680 }
3681 
3682 /* For freeing module_init on success, in case kallsyms traversing */
3683 struct mod_initfree {
3684 	struct llist_node node;
3685 	void *module_init;
3686 };
3687 
do_free_init(struct work_struct * w)3688 static void do_free_init(struct work_struct *w)
3689 {
3690 	struct llist_node *pos, *n, *list;
3691 	struct mod_initfree *initfree;
3692 
3693 	list = llist_del_all(&init_free_list);
3694 
3695 	synchronize_rcu();
3696 
3697 	llist_for_each_safe(pos, n, list) {
3698 		initfree = container_of(pos, struct mod_initfree, node);
3699 		module_memfree(initfree->module_init);
3700 		kfree(initfree);
3701 	}
3702 }
3703 
3704 /*
3705  * This is where the real work happens.
3706  *
3707  * Keep it uninlined to provide a reliable breakpoint target, e.g. for the gdb
3708  * helper command 'lx-symbols'.
3709  */
do_init_module(struct module * mod)3710 static noinline int do_init_module(struct module *mod)
3711 {
3712 	int ret = 0;
3713 	struct mod_initfree *freeinit;
3714 
3715 	freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
3716 	if (!freeinit) {
3717 		ret = -ENOMEM;
3718 		goto fail;
3719 	}
3720 	freeinit->module_init = mod->init_layout.base;
3721 
3722 	/*
3723 	 * We want to find out whether @mod uses async during init.  Clear
3724 	 * PF_USED_ASYNC.  async_schedule*() will set it.
3725 	 */
3726 	current->flags &= ~PF_USED_ASYNC;
3727 
3728 	do_mod_ctors(mod);
3729 	/* Start the module */
3730 	if (mod->init != NULL)
3731 		ret = do_one_initcall(mod->init);
3732 	if (ret < 0) {
3733 		goto fail_free_freeinit;
3734 	}
3735 	if (ret > 0) {
3736 		pr_warn("%s: '%s'->init suspiciously returned %d, it should "
3737 			"follow 0/-E convention\n"
3738 			"%s: loading module anyway...\n",
3739 			__func__, mod->name, ret, __func__);
3740 		dump_stack();
3741 	}
3742 
3743 	/* Now it's a first class citizen! */
3744 	mod->state = MODULE_STATE_LIVE;
3745 	blocking_notifier_call_chain(&module_notify_list,
3746 				     MODULE_STATE_LIVE, mod);
3747 
3748 	/* Delay uevent until module has finished its init routine */
3749 	kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
3750 
3751 	/*
3752 	 * We need to finish all async code before the module init sequence
3753 	 * is done.  This has potential to deadlock.  For example, a newly
3754 	 * detected block device can trigger request_module() of the
3755 	 * default iosched from async probing task.  Once userland helper
3756 	 * reaches here, async_synchronize_full() will wait on the async
3757 	 * task waiting on request_module() and deadlock.
3758 	 *
3759 	 * This deadlock is avoided by perfomring async_synchronize_full()
3760 	 * iff module init queued any async jobs.  This isn't a full
3761 	 * solution as it will deadlock the same if module loading from
3762 	 * async jobs nests more than once; however, due to the various
3763 	 * constraints, this hack seems to be the best option for now.
3764 	 * Please refer to the following thread for details.
3765 	 *
3766 	 * http://thread.gmane.org/gmane.linux.kernel/1420814
3767 	 */
3768 	if (!mod->async_probe_requested && (current->flags & PF_USED_ASYNC))
3769 		async_synchronize_full();
3770 
3771 	ftrace_free_mem(mod, mod->init_layout.base, mod->init_layout.base +
3772 			mod->init_layout.size);
3773 	mutex_lock(&module_mutex);
3774 	/* Drop initial reference. */
3775 	module_put(mod);
3776 	trim_init_extable(mod);
3777 #ifdef CONFIG_KALLSYMS
3778 	/* Switch to core kallsyms now init is done: kallsyms may be walking! */
3779 	rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
3780 #endif
3781 	module_enable_ro(mod, true);
3782 	mod_tree_remove_init(mod);
3783 	module_arch_freeing_init(mod);
3784 	mod->init_layout.base = NULL;
3785 	mod->init_layout.size = 0;
3786 	mod->init_layout.ro_size = 0;
3787 	mod->init_layout.ro_after_init_size = 0;
3788 	mod->init_layout.text_size = 0;
3789 	/*
3790 	 * We want to free module_init, but be aware that kallsyms may be
3791 	 * walking this with preempt disabled.  In all the failure paths, we
3792 	 * call synchronize_rcu(), but we don't want to slow down the success
3793 	 * path. module_memfree() cannot be called in an interrupt, so do the
3794 	 * work and call synchronize_rcu() in a work queue.
3795 	 *
3796 	 * Note that module_alloc() on most architectures creates W+X page
3797 	 * mappings which won't be cleaned up until do_free_init() runs.  Any
3798 	 * code such as mark_rodata_ro() which depends on those mappings to
3799 	 * be cleaned up needs to sync with the queued work - ie
3800 	 * rcu_barrier()
3801 	 */
3802 	if (llist_add(&freeinit->node, &init_free_list))
3803 		schedule_work(&init_free_wq);
3804 
3805 	mutex_unlock(&module_mutex);
3806 	wake_up_all(&module_wq);
3807 
3808 	return 0;
3809 
3810 fail_free_freeinit:
3811 	kfree(freeinit);
3812 fail:
3813 	/* Try to protect us from buggy refcounters. */
3814 	mod->state = MODULE_STATE_GOING;
3815 	synchronize_rcu();
3816 	module_put(mod);
3817 	blocking_notifier_call_chain(&module_notify_list,
3818 				     MODULE_STATE_GOING, mod);
3819 	klp_module_going(mod);
3820 	ftrace_release_mod(mod);
3821 	free_module(mod);
3822 	wake_up_all(&module_wq);
3823 	return ret;
3824 }
3825 
may_init_module(void)3826 static int may_init_module(void)
3827 {
3828 	if (!capable(CAP_SYS_MODULE) || modules_disabled)
3829 		return -EPERM;
3830 
3831 	return 0;
3832 }
3833 
3834 /*
3835  * We try to place it in the list now to make sure it's unique before
3836  * we dedicate too many resources.  In particular, temporary percpu
3837  * memory exhaustion.
3838  */
add_unformed_module(struct module * mod)3839 static int add_unformed_module(struct module *mod)
3840 {
3841 	int err;
3842 	struct module *old;
3843 
3844 	mod->state = MODULE_STATE_UNFORMED;
3845 
3846 again:
3847 	mutex_lock(&module_mutex);
3848 	old = find_module_all(mod->name, strlen(mod->name), true);
3849 	if (old != NULL) {
3850 		if (old->state != MODULE_STATE_LIVE) {
3851 			/* Wait in case it fails to load. */
3852 			mutex_unlock(&module_mutex);
3853 			err = wait_event_interruptible(module_wq,
3854 					       finished_loading(mod->name));
3855 			if (err)
3856 				goto out_unlocked;
3857 			goto again;
3858 		}
3859 		err = -EEXIST;
3860 		goto out;
3861 	}
3862 	mod_update_bounds(mod);
3863 	list_add_rcu(&mod->list, &modules);
3864 	mod_tree_insert(mod);
3865 	err = 0;
3866 
3867 out:
3868 	mutex_unlock(&module_mutex);
3869 out_unlocked:
3870 	return err;
3871 }
3872 
complete_formation(struct module * mod,struct load_info * info)3873 static int complete_formation(struct module *mod, struct load_info *info)
3874 {
3875 	int err;
3876 
3877 	mutex_lock(&module_mutex);
3878 
3879 	/* Find duplicate symbols (must be called under lock). */
3880 	err = verify_exported_symbols(mod);
3881 	if (err < 0)
3882 		goto out;
3883 
3884 	/* This relies on module_mutex for list integrity. */
3885 	module_bug_finalize(info->hdr, info->sechdrs, mod);
3886 
3887 	module_enable_ro(mod, false);
3888 	module_enable_nx(mod);
3889 	module_enable_x(mod);
3890 
3891 	/* Mark state as coming so strong_try_module_get() ignores us,
3892 	 * but kallsyms etc. can see us. */
3893 	mod->state = MODULE_STATE_COMING;
3894 	mutex_unlock(&module_mutex);
3895 
3896 	return 0;
3897 
3898 out:
3899 	mutex_unlock(&module_mutex);
3900 	return err;
3901 }
3902 
prepare_coming_module(struct module * mod)3903 static int prepare_coming_module(struct module *mod)
3904 {
3905 	int err;
3906 
3907 	ftrace_module_enable(mod);
3908 	err = klp_module_coming(mod);
3909 	if (err)
3910 		return err;
3911 
3912 	err = blocking_notifier_call_chain_robust(&module_notify_list,
3913 			MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
3914 	err = notifier_to_errno(err);
3915 	if (err)
3916 		klp_module_going(mod);
3917 
3918 	return err;
3919 }
3920 
unknown_module_param_cb(char * param,char * val,const char * modname,void * arg)3921 static int unknown_module_param_cb(char *param, char *val, const char *modname,
3922 				   void *arg)
3923 {
3924 	struct module *mod = arg;
3925 	int ret;
3926 
3927 	if (strcmp(param, "async_probe") == 0) {
3928 		mod->async_probe_requested = true;
3929 		return 0;
3930 	}
3931 
3932 	/* Check for magic 'dyndbg' arg */
3933 	ret = ddebug_dyndbg_module_param_cb(param, val, modname);
3934 	if (ret != 0)
3935 		pr_warn("%s: unknown parameter '%s' ignored\n", modname, param);
3936 	return 0;
3937 }
3938 
3939 static void cfi_init(struct module *mod);
3940 
3941 /* Allocate and load the module: note that size of section 0 is always
3942    zero, and we rely on this for optional sections. */
load_module(struct load_info * info,const char __user * uargs,int flags)3943 static int load_module(struct load_info *info, const char __user *uargs,
3944 		       int flags)
3945 {
3946 	struct module *mod;
3947 	long err = 0;
3948 	char *after_dashes;
3949 
3950 	/*
3951 	 * Do the signature check (if any) first. All that
3952 	 * the signature check needs is info->len, it does
3953 	 * not need any of the section info. That can be
3954 	 * set up later. This will minimize the chances
3955 	 * of a corrupt module causing problems before
3956 	 * we even get to the signature check.
3957 	 *
3958 	 * The check will also adjust info->len by stripping
3959 	 * off the sig length at the end of the module, making
3960 	 * checks against info->len more correct.
3961 	 */
3962 	err = module_sig_check(info, flags);
3963 	if (err)
3964 		goto free_copy;
3965 
3966 	/*
3967 	 * Do basic sanity checks against the ELF header and
3968 	 * sections.
3969 	 */
3970 	err = elf_validity_check(info);
3971 	if (err) {
3972 		pr_err("Module has invalid ELF structures\n");
3973 		goto free_copy;
3974 	}
3975 
3976 	/*
3977 	 * Everything checks out, so set up the section info
3978 	 * in the info structure.
3979 	 */
3980 	err = setup_load_info(info, flags);
3981 	if (err)
3982 		goto free_copy;
3983 
3984 	/*
3985 	 * Now that we know we have the correct module name, check
3986 	 * if it's blacklisted.
3987 	 */
3988 	if (blacklisted(info->name)) {
3989 		err = -EPERM;
3990 		pr_err("Module %s is blacklisted\n", info->name);
3991 		goto free_copy;
3992 	}
3993 
3994 	err = rewrite_section_headers(info, flags);
3995 	if (err)
3996 		goto free_copy;
3997 
3998 	/* Check module struct version now, before we try to use module. */
3999 	if (!check_modstruct_version(info, info->mod)) {
4000 		err = -ENOEXEC;
4001 		goto free_copy;
4002 	}
4003 
4004 	/* Figure out module layout, and allocate all the memory. */
4005 	mod = layout_and_allocate(info, flags);
4006 	if (IS_ERR(mod)) {
4007 		err = PTR_ERR(mod);
4008 		goto free_copy;
4009 	}
4010 
4011 	audit_log_kern_module(mod->name);
4012 
4013 	/* Reserve our place in the list. */
4014 	err = add_unformed_module(mod);
4015 	if (err)
4016 		goto free_module;
4017 
4018 #ifdef CONFIG_MODULE_SIG
4019 	mod->sig_ok = info->sig_ok;
4020 	if (!mod->sig_ok) {
4021 		pr_notice_once("%s: module verification failed: signature "
4022 			       "and/or required key missing - tainting "
4023 			       "kernel\n", mod->name);
4024 		add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
4025 	}
4026 #endif
4027 
4028 	/* To avoid stressing percpu allocator, do this once we're unique. */
4029 	err = percpu_modalloc(mod, info);
4030 	if (err)
4031 		goto unlink_mod;
4032 
4033 	/* Now module is in final location, initialize linked lists, etc. */
4034 	err = module_unload_init(mod);
4035 	if (err)
4036 		goto unlink_mod;
4037 
4038 	init_param_lock(mod);
4039 
4040 	/* Now we've got everything in the final locations, we can
4041 	 * find optional sections. */
4042 	err = find_module_sections(mod, info);
4043 	if (err)
4044 		goto free_unload;
4045 
4046 	err = check_module_license_and_versions(mod);
4047 	if (err)
4048 		goto free_unload;
4049 
4050 	/* Set up MODINFO_ATTR fields */
4051 	setup_modinfo(mod, info);
4052 
4053 	/* Fix up syms, so that st_value is a pointer to location. */
4054 	err = simplify_symbols(mod, info);
4055 	if (err < 0)
4056 		goto free_modinfo;
4057 
4058 	err = apply_relocations(mod, info);
4059 	if (err < 0)
4060 		goto free_modinfo;
4061 
4062 	err = post_relocation(mod, info);
4063 	if (err < 0)
4064 		goto free_modinfo;
4065 
4066 	flush_module_icache(mod);
4067 
4068 	/* Setup CFI for the module. */
4069 	cfi_init(mod);
4070 
4071 	/* Now copy in args */
4072 	mod->args = strndup_user(uargs, ~0UL >> 1);
4073 	if (IS_ERR(mod->args)) {
4074 		err = PTR_ERR(mod->args);
4075 		goto free_arch_cleanup;
4076 	}
4077 
4078 	dynamic_debug_setup(mod, info->debug, info->num_debug);
4079 
4080 	/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
4081 	ftrace_module_init(mod);
4082 
4083 	/* Finally it's fully formed, ready to start executing. */
4084 	err = complete_formation(mod, info);
4085 	if (err)
4086 		goto ddebug_cleanup;
4087 
4088 	err = prepare_coming_module(mod);
4089 	if (err)
4090 		goto bug_cleanup;
4091 
4092 	/* Module is ready to execute: parsing args may do that. */
4093 	after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
4094 				  -32768, 32767, mod,
4095 				  unknown_module_param_cb);
4096 	if (IS_ERR(after_dashes)) {
4097 		err = PTR_ERR(after_dashes);
4098 		goto coming_cleanup;
4099 	} else if (after_dashes) {
4100 		pr_warn("%s: parameters '%s' after `--' ignored\n",
4101 		       mod->name, after_dashes);
4102 	}
4103 
4104 	/* Link in to sysfs. */
4105 	err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
4106 	if (err < 0)
4107 		goto coming_cleanup;
4108 
4109 	if (is_livepatch_module(mod)) {
4110 		err = copy_module_elf(mod, info);
4111 		if (err < 0)
4112 			goto sysfs_cleanup;
4113 	}
4114 
4115 	/* Get rid of temporary copy. */
4116 	free_copy(info);
4117 
4118 	/* Done! */
4119 	trace_module_load(mod);
4120 
4121 	return do_init_module(mod);
4122 
4123  sysfs_cleanup:
4124 	mod_sysfs_teardown(mod);
4125  coming_cleanup:
4126 	mod->state = MODULE_STATE_GOING;
4127 	destroy_params(mod->kp, mod->num_kp);
4128 	blocking_notifier_call_chain(&module_notify_list,
4129 				     MODULE_STATE_GOING, mod);
4130 	klp_module_going(mod);
4131  bug_cleanup:
4132 	mod->state = MODULE_STATE_GOING;
4133 	/* module_bug_cleanup needs module_mutex protection */
4134 	mutex_lock(&module_mutex);
4135 	module_bug_cleanup(mod);
4136 	mutex_unlock(&module_mutex);
4137 
4138  ddebug_cleanup:
4139 	ftrace_release_mod(mod);
4140 	dynamic_debug_remove(mod, info->debug);
4141 	synchronize_rcu();
4142 	kfree(mod->args);
4143  free_arch_cleanup:
4144 	cfi_cleanup(mod);
4145 	module_arch_cleanup(mod);
4146  free_modinfo:
4147 	free_modinfo(mod);
4148  free_unload:
4149 	module_unload_free(mod);
4150  unlink_mod:
4151 	mutex_lock(&module_mutex);
4152 	/* Unlink carefully: kallsyms could be walking list. */
4153 	list_del_rcu(&mod->list);
4154 	mod_tree_remove(mod);
4155 	wake_up_all(&module_wq);
4156 	/* Wait for RCU-sched synchronizing before releasing mod->list. */
4157 	synchronize_rcu();
4158 	mutex_unlock(&module_mutex);
4159  free_module:
4160 	/* Free lock-classes; relies on the preceding sync_rcu() */
4161 	lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
4162 
4163 	module_deallocate(mod, info);
4164  free_copy:
4165 	free_copy(info);
4166 	return err;
4167 }
4168 
SYSCALL_DEFINE3(init_module,void __user *,umod,unsigned long,len,const char __user *,uargs)4169 SYSCALL_DEFINE3(init_module, void __user *, umod,
4170 		unsigned long, len, const char __user *, uargs)
4171 {
4172 	int err;
4173 	struct load_info info = { };
4174 
4175 	err = may_init_module();
4176 	if (err)
4177 		return err;
4178 
4179 	pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
4180 	       umod, len, uargs);
4181 
4182 	err = copy_module_from_user(umod, len, &info);
4183 	if (err)
4184 		return err;
4185 
4186 	return load_module(&info, uargs, 0);
4187 }
4188 
SYSCALL_DEFINE3(finit_module,int,fd,const char __user *,uargs,int,flags)4189 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
4190 {
4191 	struct load_info info = { };
4192 	void *hdr = NULL;
4193 	int err;
4194 
4195 	err = may_init_module();
4196 	if (err)
4197 		return err;
4198 
4199 	pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
4200 
4201 	if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
4202 		      |MODULE_INIT_IGNORE_VERMAGIC))
4203 		return -EINVAL;
4204 
4205 	err = kernel_read_file_from_fd(fd, 0, &hdr, INT_MAX, NULL,
4206 				       READING_MODULE);
4207 	if (err < 0)
4208 		return err;
4209 	info.hdr = hdr;
4210 	info.len = err;
4211 
4212 	return load_module(&info, uargs, flags);
4213 }
4214 
within(unsigned long addr,void * start,unsigned long size)4215 static inline int within(unsigned long addr, void *start, unsigned long size)
4216 {
4217 	return ((void *)addr >= start && (void *)addr < start + size);
4218 }
4219 
4220 #ifdef CONFIG_KALLSYMS
4221 /*
4222  * This ignores the intensely annoying "mapping symbols" found
4223  * in ARM ELF files: $a, $t and $d.
4224  */
is_arm_mapping_symbol(const char * str)4225 static inline int is_arm_mapping_symbol(const char *str)
4226 {
4227 	if (str[0] == '.' && str[1] == 'L')
4228 		return true;
4229 	return str[0] == '$' && strchr("axtd", str[1])
4230 	       && (str[2] == '\0' || str[2] == '.');
4231 }
4232 
kallsyms_symbol_name(struct mod_kallsyms * kallsyms,unsigned int symnum)4233 static const char *kallsyms_symbol_name(struct mod_kallsyms *kallsyms, unsigned int symnum)
4234 {
4235 	return kallsyms->strtab + kallsyms->symtab[symnum].st_name;
4236 }
4237 
4238 /*
4239  * Given a module and address, find the corresponding symbol and return its name
4240  * while providing its size and offset if needed.
4241  */
find_kallsyms_symbol(struct module * mod,unsigned long addr,unsigned long * size,unsigned long * offset)4242 static const char *find_kallsyms_symbol(struct module *mod,
4243 					unsigned long addr,
4244 					unsigned long *size,
4245 					unsigned long *offset)
4246 {
4247 	unsigned int i, best = 0;
4248 	unsigned long nextval, bestval;
4249 	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
4250 
4251 	/* At worse, next value is at end of module */
4252 	if (within_module_init(addr, mod))
4253 		nextval = (unsigned long)mod->init_layout.base+mod->init_layout.text_size;
4254 	else
4255 		nextval = (unsigned long)mod->core_layout.base+mod->core_layout.text_size;
4256 
4257 	bestval = kallsyms_symbol_value(&kallsyms->symtab[best]);
4258 
4259 	/* Scan for closest preceding symbol, and next symbol. (ELF
4260 	   starts real symbols at 1). */
4261 	for (i = 1; i < kallsyms->num_symtab; i++) {
4262 		const Elf_Sym *sym = &kallsyms->symtab[i];
4263 		unsigned long thisval = kallsyms_symbol_value(sym);
4264 
4265 		if (sym->st_shndx == SHN_UNDEF)
4266 			continue;
4267 
4268 		/* We ignore unnamed symbols: they're uninformative
4269 		 * and inserted at a whim. */
4270 		if (*kallsyms_symbol_name(kallsyms, i) == '\0'
4271 		    || is_arm_mapping_symbol(kallsyms_symbol_name(kallsyms, i)))
4272 			continue;
4273 
4274 		if (thisval <= addr && thisval > bestval) {
4275 			best = i;
4276 			bestval = thisval;
4277 		}
4278 		if (thisval > addr && thisval < nextval)
4279 			nextval = thisval;
4280 	}
4281 
4282 	if (!best)
4283 		return NULL;
4284 
4285 	if (size)
4286 		*size = nextval - bestval;
4287 	if (offset)
4288 		*offset = addr - bestval;
4289 
4290 	return kallsyms_symbol_name(kallsyms, best);
4291 }
4292 
dereference_module_function_descriptor(struct module * mod,void * ptr)4293 void * __weak dereference_module_function_descriptor(struct module *mod,
4294 						     void *ptr)
4295 {
4296 	return ptr;
4297 }
4298 
4299 /* For kallsyms to ask for address resolution.  NULL means not found.  Careful
4300  * not to lock to avoid deadlock on oopses, simply disable preemption. */
module_address_lookup(unsigned long addr,unsigned long * size,unsigned long * offset,char ** modname,char * namebuf)4301 const char *module_address_lookup(unsigned long addr,
4302 			    unsigned long *size,
4303 			    unsigned long *offset,
4304 			    char **modname,
4305 			    char *namebuf)
4306 {
4307 	const char *ret = NULL;
4308 	struct module *mod;
4309 
4310 	preempt_disable();
4311 	mod = __module_address(addr);
4312 	if (mod) {
4313 		if (modname)
4314 			*modname = mod->name;
4315 
4316 		ret = find_kallsyms_symbol(mod, addr, size, offset);
4317 	}
4318 	/* Make a copy in here where it's safe */
4319 	if (ret) {
4320 		strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
4321 		ret = namebuf;
4322 	}
4323 	preempt_enable();
4324 
4325 	return ret;
4326 }
4327 
lookup_module_symbol_name(unsigned long addr,char * symname)4328 int lookup_module_symbol_name(unsigned long addr, char *symname)
4329 {
4330 	struct module *mod;
4331 
4332 	preempt_disable();
4333 	list_for_each_entry_rcu(mod, &modules, list) {
4334 		if (mod->state == MODULE_STATE_UNFORMED)
4335 			continue;
4336 		if (within_module(addr, mod)) {
4337 			const char *sym;
4338 
4339 			sym = find_kallsyms_symbol(mod, addr, NULL, NULL);
4340 			if (!sym)
4341 				goto out;
4342 
4343 			strlcpy(symname, sym, KSYM_NAME_LEN);
4344 			preempt_enable();
4345 			return 0;
4346 		}
4347 	}
4348 out:
4349 	preempt_enable();
4350 	return -ERANGE;
4351 }
4352 
lookup_module_symbol_attrs(unsigned long addr,unsigned long * size,unsigned long * offset,char * modname,char * name)4353 int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
4354 			unsigned long *offset, char *modname, char *name)
4355 {
4356 	struct module *mod;
4357 
4358 	preempt_disable();
4359 	list_for_each_entry_rcu(mod, &modules, list) {
4360 		if (mod->state == MODULE_STATE_UNFORMED)
4361 			continue;
4362 		if (within_module(addr, mod)) {
4363 			const char *sym;
4364 
4365 			sym = find_kallsyms_symbol(mod, addr, size, offset);
4366 			if (!sym)
4367 				goto out;
4368 			if (modname)
4369 				strlcpy(modname, mod->name, MODULE_NAME_LEN);
4370 			if (name)
4371 				strlcpy(name, sym, KSYM_NAME_LEN);
4372 			preempt_enable();
4373 			return 0;
4374 		}
4375 	}
4376 out:
4377 	preempt_enable();
4378 	return -ERANGE;
4379 }
4380 
module_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * name,char * module_name,int * exported)4381 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
4382 			char *name, char *module_name, int *exported)
4383 {
4384 	struct module *mod;
4385 
4386 	preempt_disable();
4387 	list_for_each_entry_rcu(mod, &modules, list) {
4388 		struct mod_kallsyms *kallsyms;
4389 
4390 		if (mod->state == MODULE_STATE_UNFORMED)
4391 			continue;
4392 		kallsyms = rcu_dereference_sched(mod->kallsyms);
4393 		if (symnum < kallsyms->num_symtab) {
4394 			const Elf_Sym *sym = &kallsyms->symtab[symnum];
4395 
4396 			*value = kallsyms_symbol_value(sym);
4397 			*type = kallsyms->typetab[symnum];
4398 			strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
4399 			strlcpy(module_name, mod->name, MODULE_NAME_LEN);
4400 			*exported = is_exported(name, *value, mod);
4401 			preempt_enable();
4402 			return 0;
4403 		}
4404 		symnum -= kallsyms->num_symtab;
4405 	}
4406 	preempt_enable();
4407 	return -ERANGE;
4408 }
4409 
4410 /* Given a module and name of symbol, find and return the symbol's value */
find_kallsyms_symbol_value(struct module * mod,const char * name)4411 static unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)
4412 {
4413 	unsigned int i;
4414 	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
4415 
4416 	for (i = 0; i < kallsyms->num_symtab; i++) {
4417 		const Elf_Sym *sym = &kallsyms->symtab[i];
4418 
4419 		if (strcmp(name, kallsyms_symbol_name(kallsyms, i)) == 0 &&
4420 		    sym->st_shndx != SHN_UNDEF)
4421 			return kallsyms_symbol_value(sym);
4422 	}
4423 	return 0;
4424 }
4425 
4426 /* Look for this name: can be of form module:name. */
module_kallsyms_lookup_name(const char * name)4427 unsigned long module_kallsyms_lookup_name(const char *name)
4428 {
4429 	struct module *mod;
4430 	char *colon;
4431 	unsigned long ret = 0;
4432 
4433 	/* Don't lock: we're in enough trouble already. */
4434 	preempt_disable();
4435 	if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
4436 		if ((mod = find_module_all(name, colon - name, false)) != NULL)
4437 			ret = find_kallsyms_symbol_value(mod, colon+1);
4438 	} else {
4439 		list_for_each_entry_rcu(mod, &modules, list) {
4440 			if (mod->state == MODULE_STATE_UNFORMED)
4441 				continue;
4442 			if ((ret = find_kallsyms_symbol_value(mod, name)) != 0)
4443 				break;
4444 		}
4445 	}
4446 	preempt_enable();
4447 	return ret;
4448 }
4449 
module_kallsyms_on_each_symbol(int (* fn)(void *,const char *,struct module *,unsigned long),void * data)4450 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
4451 					     struct module *, unsigned long),
4452 				   void *data)
4453 {
4454 	struct module *mod;
4455 	unsigned int i;
4456 	int ret;
4457 
4458 	module_assert_mutex();
4459 
4460 	list_for_each_entry(mod, &modules, list) {
4461 		/* We hold module_mutex: no need for rcu_dereference_sched */
4462 		struct mod_kallsyms *kallsyms = mod->kallsyms;
4463 
4464 		if (mod->state == MODULE_STATE_UNFORMED)
4465 			continue;
4466 		for (i = 0; i < kallsyms->num_symtab; i++) {
4467 			const Elf_Sym *sym = &kallsyms->symtab[i];
4468 
4469 			if (sym->st_shndx == SHN_UNDEF)
4470 				continue;
4471 
4472 			ret = fn(data, kallsyms_symbol_name(kallsyms, i),
4473 				 mod, kallsyms_symbol_value(sym));
4474 			if (ret != 0)
4475 				return ret;
4476 		}
4477 	}
4478 	return 0;
4479 }
4480 #endif /* CONFIG_KALLSYMS */
4481 
cfi_init(struct module * mod)4482 static void cfi_init(struct module *mod)
4483 {
4484 #ifdef CONFIG_CFI_CLANG
4485 	initcall_t *init;
4486 	exitcall_t *exit;
4487 
4488 	rcu_read_lock_sched();
4489 	mod->cfi_check = (cfi_check_fn)
4490 		find_kallsyms_symbol_value(mod, "__cfi_check");
4491 	init = (initcall_t *)
4492 		find_kallsyms_symbol_value(mod, "__cfi_jt_init_module");
4493 	exit = (exitcall_t *)
4494 		find_kallsyms_symbol_value(mod, "__cfi_jt_cleanup_module");
4495 	rcu_read_unlock_sched();
4496 
4497 	/* Fix init/exit functions to point to the CFI jump table */
4498 	if (init)
4499 		mod->init = *init;
4500 #ifdef CONFIG_MODULE_UNLOAD
4501 	if (exit)
4502 		mod->exit = *exit;
4503 #endif
4504 
4505 	cfi_module_add(mod, module_addr_min);
4506 #endif
4507 }
4508 
cfi_cleanup(struct module * mod)4509 static void cfi_cleanup(struct module *mod)
4510 {
4511 #ifdef CONFIG_CFI_CLANG
4512 	cfi_module_remove(mod, module_addr_min);
4513 #endif
4514 }
4515 
4516 /* Maximum number of characters written by module_flags() */
4517 #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
4518 
4519 /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
module_flags(struct module * mod,char * buf)4520 static char *module_flags(struct module *mod, char *buf)
4521 {
4522 	int bx = 0;
4523 
4524 	BUG_ON(mod->state == MODULE_STATE_UNFORMED);
4525 	if (mod->taints ||
4526 	    mod->state == MODULE_STATE_GOING ||
4527 	    mod->state == MODULE_STATE_COMING) {
4528 		buf[bx++] = '(';
4529 		bx += module_flags_taint(mod, buf + bx);
4530 		/* Show a - for module-is-being-unloaded */
4531 		if (mod->state == MODULE_STATE_GOING)
4532 			buf[bx++] = '-';
4533 		/* Show a + for module-is-being-loaded */
4534 		if (mod->state == MODULE_STATE_COMING)
4535 			buf[bx++] = '+';
4536 		buf[bx++] = ')';
4537 	}
4538 	buf[bx] = '\0';
4539 
4540 	return buf;
4541 }
4542 
4543 #ifdef CONFIG_PROC_FS
4544 /* Called by the /proc file system to return a list of modules. */
m_start(struct seq_file * m,loff_t * pos)4545 static void *m_start(struct seq_file *m, loff_t *pos)
4546 {
4547 	mutex_lock(&module_mutex);
4548 	return seq_list_start(&modules, *pos);
4549 }
4550 
m_next(struct seq_file * m,void * p,loff_t * pos)4551 static void *m_next(struct seq_file *m, void *p, loff_t *pos)
4552 {
4553 	return seq_list_next(p, &modules, pos);
4554 }
4555 
m_stop(struct seq_file * m,void * p)4556 static void m_stop(struct seq_file *m, void *p)
4557 {
4558 	mutex_unlock(&module_mutex);
4559 }
4560 
m_show(struct seq_file * m,void * p)4561 static int m_show(struct seq_file *m, void *p)
4562 {
4563 	struct module *mod = list_entry(p, struct module, list);
4564 	char buf[MODULE_FLAGS_BUF_SIZE];
4565 	void *value;
4566 
4567 	/* We always ignore unformed modules. */
4568 	if (mod->state == MODULE_STATE_UNFORMED)
4569 		return 0;
4570 
4571 	seq_printf(m, "%s %u",
4572 		   mod->name, mod->init_layout.size + mod->core_layout.size);
4573 	print_unload_info(m, mod);
4574 
4575 	/* Informative for users. */
4576 	seq_printf(m, " %s",
4577 		   mod->state == MODULE_STATE_GOING ? "Unloading" :
4578 		   mod->state == MODULE_STATE_COMING ? "Loading" :
4579 		   "Live");
4580 	/* Used by oprofile and other similar tools. */
4581 	value = m->private ? NULL : mod->core_layout.base;
4582 	seq_printf(m, " 0x%px", value);
4583 
4584 	/* Taints info */
4585 	if (mod->taints)
4586 		seq_printf(m, " %s", module_flags(mod, buf));
4587 
4588 	seq_puts(m, "\n");
4589 	return 0;
4590 }
4591 
4592 /* Format: modulename size refcount deps address
4593 
4594    Where refcount is a number or -, and deps is a comma-separated list
4595    of depends or -.
4596 */
4597 static const struct seq_operations modules_op = {
4598 	.start	= m_start,
4599 	.next	= m_next,
4600 	.stop	= m_stop,
4601 	.show	= m_show
4602 };
4603 
4604 /*
4605  * This also sets the "private" pointer to non-NULL if the
4606  * kernel pointers should be hidden (so you can just test
4607  * "m->private" to see if you should keep the values private).
4608  *
4609  * We use the same logic as for /proc/kallsyms.
4610  */
modules_open(struct inode * inode,struct file * file)4611 static int modules_open(struct inode *inode, struct file *file)
4612 {
4613 	int err = seq_open(file, &modules_op);
4614 
4615 	if (!err) {
4616 		struct seq_file *m = file->private_data;
4617 		m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul;
4618 	}
4619 
4620 	return err;
4621 }
4622 
4623 static const struct proc_ops modules_proc_ops = {
4624 	.proc_flags	= PROC_ENTRY_PERMANENT,
4625 	.proc_open	= modules_open,
4626 	.proc_read	= seq_read,
4627 	.proc_lseek	= seq_lseek,
4628 	.proc_release	= seq_release,
4629 };
4630 
proc_modules_init(void)4631 static int __init proc_modules_init(void)
4632 {
4633 	proc_create("modules", 0, NULL, &modules_proc_ops);
4634 	return 0;
4635 }
4636 module_init(proc_modules_init);
4637 #endif
4638 
4639 /* Given an address, look for it in the module exception tables. */
search_module_extables(unsigned long addr)4640 const struct exception_table_entry *search_module_extables(unsigned long addr)
4641 {
4642 	const struct exception_table_entry *e = NULL;
4643 	struct module *mod;
4644 
4645 	preempt_disable();
4646 	mod = __module_address(addr);
4647 	if (!mod)
4648 		goto out;
4649 
4650 	if (!mod->num_exentries)
4651 		goto out;
4652 
4653 	e = search_extable(mod->extable,
4654 			   mod->num_exentries,
4655 			   addr);
4656 out:
4657 	preempt_enable();
4658 
4659 	/*
4660 	 * Now, if we found one, we are running inside it now, hence
4661 	 * we cannot unload the module, hence no refcnt needed.
4662 	 */
4663 	return e;
4664 }
4665 
4666 /*
4667  * is_module_address - is this address inside a module?
4668  * @addr: the address to check.
4669  *
4670  * See is_module_text_address() if you simply want to see if the address
4671  * is code (not data).
4672  */
is_module_address(unsigned long addr)4673 bool is_module_address(unsigned long addr)
4674 {
4675 	bool ret;
4676 
4677 	preempt_disable();
4678 	ret = __module_address(addr) != NULL;
4679 	preempt_enable();
4680 
4681 	return ret;
4682 }
4683 
4684 /*
4685  * __module_address - get the module which contains an address.
4686  * @addr: the address.
4687  *
4688  * Must be called with preempt disabled or module mutex held so that
4689  * module doesn't get freed during this.
4690  */
__module_address(unsigned long addr)4691 struct module *__module_address(unsigned long addr)
4692 {
4693 	struct module *mod;
4694 
4695 	if (addr < module_addr_min || addr > module_addr_max)
4696 		return NULL;
4697 
4698 	module_assert_mutex_or_preempt();
4699 
4700 	mod = mod_find(addr);
4701 	if (mod) {
4702 		BUG_ON(!within_module(addr, mod));
4703 		if (mod->state == MODULE_STATE_UNFORMED)
4704 			mod = NULL;
4705 	}
4706 	return mod;
4707 }
4708 
4709 /*
4710  * is_module_text_address - is this address inside module code?
4711  * @addr: the address to check.
4712  *
4713  * See is_module_address() if you simply want to see if the address is
4714  * anywhere in a module.  See kernel_text_address() for testing if an
4715  * address corresponds to kernel or module code.
4716  */
is_module_text_address(unsigned long addr)4717 bool is_module_text_address(unsigned long addr)
4718 {
4719 	bool ret;
4720 
4721 	preempt_disable();
4722 	ret = __module_text_address(addr) != NULL;
4723 	preempt_enable();
4724 
4725 	return ret;
4726 }
4727 
4728 /*
4729  * __module_text_address - get the module whose code contains an address.
4730  * @addr: the address.
4731  *
4732  * Must be called with preempt disabled or module mutex held so that
4733  * module doesn't get freed during this.
4734  */
__module_text_address(unsigned long addr)4735 struct module *__module_text_address(unsigned long addr)
4736 {
4737 	struct module *mod = __module_address(addr);
4738 	if (mod) {
4739 		/* Make sure it's within the text section. */
4740 		if (!within(addr, mod->init_layout.base, mod->init_layout.text_size)
4741 		    && !within(addr, mod->core_layout.base, mod->core_layout.text_size))
4742 			mod = NULL;
4743 	}
4744 	return mod;
4745 }
4746 
4747 /* Don't grab lock, we're oopsing. */
print_modules(void)4748 void print_modules(void)
4749 {
4750 	struct module *mod;
4751 	char buf[MODULE_FLAGS_BUF_SIZE];
4752 
4753 	printk(KERN_DEFAULT "Modules linked in:");
4754 	/* Most callers should already have preempt disabled, but make sure */
4755 	preempt_disable();
4756 	list_for_each_entry_rcu(mod, &modules, list) {
4757 		if (mod->state == MODULE_STATE_UNFORMED)
4758 			continue;
4759 		pr_cont(" %s%s", mod->name, module_flags(mod, buf));
4760 	}
4761 	preempt_enable();
4762 	if (last_unloaded_module[0])
4763 		pr_cont(" [last unloaded: %s]", last_unloaded_module);
4764 	pr_cont("\n");
4765 }
4766 
4767 #ifdef CONFIG_MODVERSIONS
4768 /* Generate the signature for all relevant module structures here.
4769  * If these change, we don't want to try to parse the module. */
module_layout(struct module * mod,struct modversion_info * ver,struct kernel_param * kp,struct kernel_symbol * ks,struct tracepoint * const * tp)4770 void module_layout(struct module *mod,
4771 		   struct modversion_info *ver,
4772 		   struct kernel_param *kp,
4773 		   struct kernel_symbol *ks,
4774 		   struct tracepoint * const *tp)
4775 {
4776 }
4777 EXPORT_SYMBOL(module_layout);
4778 #endif
4779