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 = §_attrs->attrs[0];
1620 gattr = §_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, §_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 ¬es_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 = ¬es_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 ¬es_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