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 #define INCLUDE_VERMAGIC
8
9 #include <linux/export.h>
10 #include <linux/extable.h>
11 #include <linux/moduleloader.h>
12 #include <linux/module_signature.h>
13 #include <linux/trace_events.h>
14 #include <linux/init.h>
15 #include <linux/kallsyms.h>
16 #include <linux/buildid.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 #undef CREATE_TRACE_POINTS
67 #include <trace/hooks/module.h>
68 #include <trace/hooks/memory.h>
69
70 #ifndef ARCH_SHF_SMALL
71 #define ARCH_SHF_SMALL 0
72 #endif
73
74 /*
75 * Modules' sections will be aligned on page boundaries
76 * to ensure complete separation of code and data, but
77 * only when CONFIG_ARCH_HAS_STRICT_MODULE_RWX=y
78 */
79 #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
80 # define debug_align(X) ALIGN(X, PAGE_SIZE)
81 #else
82 # define debug_align(X) (X)
83 #endif
84
85 /* If this is set, the section belongs in the init part of the module */
86 #define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))
87
88 /*
89 * Mutex protects:
90 * 1) List of modules (also safely readable with preempt_disable),
91 * 2) module_use links,
92 * 3) module_addr_min/module_addr_max.
93 * (delete and add uses RCU list operations).
94 */
95 static DEFINE_MUTEX(module_mutex);
96 static LIST_HEAD(modules);
97
98 /* Work queue for freeing init sections in success case */
99 static void do_free_init(struct work_struct *w);
100 static DECLARE_WORK(init_free_wq, do_free_init);
101 static LLIST_HEAD(init_free_list);
102
103 #ifdef CONFIG_MODULES_TREE_LOOKUP
104
105 /*
106 * Use a latched RB-tree for __module_address(); this allows us to use
107 * RCU-sched lookups of the address from any context.
108 *
109 * This is conditional on PERF_EVENTS || TRACING because those can really hit
110 * __module_address() hard by doing a lot of stack unwinding; potentially from
111 * NMI context.
112 */
113
__mod_tree_val(struct latch_tree_node * n)114 static __always_inline unsigned long __mod_tree_val(struct latch_tree_node *n)
115 {
116 struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
117
118 return (unsigned long)layout->base;
119 }
120
__mod_tree_size(struct latch_tree_node * n)121 static __always_inline unsigned long __mod_tree_size(struct latch_tree_node *n)
122 {
123 struct module_layout *layout = container_of(n, struct module_layout, mtn.node);
124
125 return (unsigned long)layout->size;
126 }
127
128 static __always_inline bool
mod_tree_less(struct latch_tree_node * a,struct latch_tree_node * b)129 mod_tree_less(struct latch_tree_node *a, struct latch_tree_node *b)
130 {
131 return __mod_tree_val(a) < __mod_tree_val(b);
132 }
133
134 static __always_inline int
mod_tree_comp(void * key,struct latch_tree_node * n)135 mod_tree_comp(void *key, struct latch_tree_node *n)
136 {
137 unsigned long val = (unsigned long)key;
138 unsigned long start, end;
139
140 start = __mod_tree_val(n);
141 if (val < start)
142 return -1;
143
144 end = start + __mod_tree_size(n);
145 if (val >= end)
146 return 1;
147
148 return 0;
149 }
150
151 static const struct latch_tree_ops mod_tree_ops = {
152 .less = mod_tree_less,
153 .comp = mod_tree_comp,
154 };
155
156 static struct mod_tree_root {
157 struct latch_tree_root root;
158 unsigned long addr_min;
159 unsigned long addr_max;
160 } mod_tree __cacheline_aligned = {
161 .addr_min = -1UL,
162 };
163
164 #define module_addr_min mod_tree.addr_min
165 #define module_addr_max mod_tree.addr_max
166
__mod_tree_insert(struct mod_tree_node * node)167 static noinline void __mod_tree_insert(struct mod_tree_node *node)
168 {
169 latch_tree_insert(&node->node, &mod_tree.root, &mod_tree_ops);
170 }
171
__mod_tree_remove(struct mod_tree_node * node)172 static void __mod_tree_remove(struct mod_tree_node *node)
173 {
174 latch_tree_erase(&node->node, &mod_tree.root, &mod_tree_ops);
175 }
176
177 /*
178 * These modifications: insert, remove_init and remove; are serialized by the
179 * module_mutex.
180 */
mod_tree_insert(struct module * mod)181 static void mod_tree_insert(struct module *mod)
182 {
183 mod->core_layout.mtn.mod = mod;
184 mod->init_layout.mtn.mod = mod;
185
186 __mod_tree_insert(&mod->core_layout.mtn);
187 if (mod->init_layout.size)
188 __mod_tree_insert(&mod->init_layout.mtn);
189 }
190
mod_tree_remove_init(struct module * mod)191 static void mod_tree_remove_init(struct module *mod)
192 {
193 if (mod->init_layout.size)
194 __mod_tree_remove(&mod->init_layout.mtn);
195 }
196
mod_tree_remove(struct module * mod)197 static void mod_tree_remove(struct module *mod)
198 {
199 __mod_tree_remove(&mod->core_layout.mtn);
200 mod_tree_remove_init(mod);
201 }
202
mod_find(unsigned long addr)203 static struct module *mod_find(unsigned long addr)
204 {
205 struct latch_tree_node *ltn;
206
207 ltn = latch_tree_find((void *)addr, &mod_tree.root, &mod_tree_ops);
208 if (!ltn)
209 return NULL;
210
211 return container_of(ltn, struct mod_tree_node, node)->mod;
212 }
213
214 #else /* MODULES_TREE_LOOKUP */
215
216 static unsigned long module_addr_min = -1UL, module_addr_max = 0;
217
mod_tree_insert(struct module * mod)218 static void mod_tree_insert(struct module *mod) { }
mod_tree_remove_init(struct module * mod)219 static void mod_tree_remove_init(struct module *mod) { }
mod_tree_remove(struct module * mod)220 static void mod_tree_remove(struct module *mod) { }
221
mod_find(unsigned long addr)222 static struct module *mod_find(unsigned long addr)
223 {
224 struct module *mod;
225
226 list_for_each_entry_rcu(mod, &modules, list,
227 lockdep_is_held(&module_mutex)) {
228 if (within_module(addr, mod))
229 return mod;
230 }
231
232 return NULL;
233 }
234
235 #endif /* MODULES_TREE_LOOKUP */
236
237 /*
238 * Bounds of module text, for speeding up __module_address.
239 * Protected by module_mutex.
240 */
__mod_update_bounds(void * base,unsigned int size)241 static void __mod_update_bounds(void *base, unsigned int size)
242 {
243 unsigned long min = (unsigned long)base;
244 unsigned long max = min + size;
245
246 if (min < module_addr_min)
247 module_addr_min = min;
248 if (max > module_addr_max)
249 module_addr_max = max;
250 }
251
mod_update_bounds(struct module * mod)252 static void mod_update_bounds(struct module *mod)
253 {
254 __mod_update_bounds(mod->core_layout.base, mod->core_layout.size);
255 if (mod->init_layout.size)
256 __mod_update_bounds(mod->init_layout.base, mod->init_layout.size);
257 }
258
259 #ifdef CONFIG_KGDB_KDB
260 struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
261 #endif /* CONFIG_KGDB_KDB */
262
module_assert_mutex_or_preempt(void)263 static void module_assert_mutex_or_preempt(void)
264 {
265 #ifdef CONFIG_LOCKDEP
266 if (unlikely(!debug_locks))
267 return;
268
269 WARN_ON_ONCE(!rcu_read_lock_sched_held() &&
270 !lockdep_is_held(&module_mutex));
271 #endif
272 }
273
274 #if defined(CONFIG_MODULE_SIG) && !defined(CONFIG_MODULE_SIG_PROTECT)
275 static bool sig_enforce = IS_ENABLED(CONFIG_MODULE_SIG_FORCE);
276 module_param(sig_enforce, bool_enable_only, 0644);
277
set_module_sig_enforced(void)278 void set_module_sig_enforced(void)
279 {
280 sig_enforce = true;
281 }
282 #else
283 #define sig_enforce false
284 #endif
285
286 /*
287 * Export sig_enforce kernel cmdline parameter to allow other subsystems rely
288 * on that instead of directly to CONFIG_MODULE_SIG_FORCE config.
289 */
is_module_sig_enforced(void)290 bool is_module_sig_enforced(void)
291 {
292 return sig_enforce;
293 }
294 EXPORT_SYMBOL(is_module_sig_enforced);
295
296 /* Block module loading/unloading? */
297 int modules_disabled = 0;
298 core_param(nomodule, modules_disabled, bint, 0);
299
300 /* Waiting for a module to finish initializing? */
301 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
302
303 static BLOCKING_NOTIFIER_HEAD(module_notify_list);
304
register_module_notifier(struct notifier_block * nb)305 int register_module_notifier(struct notifier_block *nb)
306 {
307 return blocking_notifier_chain_register(&module_notify_list, nb);
308 }
309 EXPORT_SYMBOL(register_module_notifier);
310
unregister_module_notifier(struct notifier_block * nb)311 int unregister_module_notifier(struct notifier_block *nb)
312 {
313 return blocking_notifier_chain_unregister(&module_notify_list, nb);
314 }
315 EXPORT_SYMBOL(unregister_module_notifier);
316
317 /*
318 * We require a truly strong try_module_get(): 0 means success.
319 * Otherwise an error is returned due to ongoing or failed
320 * initialization etc.
321 */
strong_try_module_get(struct module * mod)322 static inline int strong_try_module_get(struct module *mod)
323 {
324 BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
325 if (mod && mod->state == MODULE_STATE_COMING)
326 return -EBUSY;
327 if (try_module_get(mod))
328 return 0;
329 else
330 return -ENOENT;
331 }
332
add_taint_module(struct module * mod,unsigned flag,enum lockdep_ok lockdep_ok)333 static inline void add_taint_module(struct module *mod, unsigned flag,
334 enum lockdep_ok lockdep_ok)
335 {
336 add_taint(flag, lockdep_ok);
337 set_bit(flag, &mod->taints);
338 }
339
340 /*
341 * A thread that wants to hold a reference to a module only while it
342 * is running can call this to safely exit. nfsd and lockd use this.
343 */
__module_put_and_exit(struct module * mod,long code)344 void __noreturn __module_put_and_exit(struct module *mod, long code)
345 {
346 module_put(mod);
347 do_exit(code);
348 }
349 EXPORT_SYMBOL(__module_put_and_exit);
350
351 /* Find a module section: 0 means not found. */
find_sec(const struct load_info * info,const char * name)352 static unsigned int find_sec(const struct load_info *info, const char *name)
353 {
354 unsigned int i;
355
356 for (i = 1; i < info->hdr->e_shnum; i++) {
357 Elf_Shdr *shdr = &info->sechdrs[i];
358 /* Alloc bit cleared means "ignore it." */
359 if ((shdr->sh_flags & SHF_ALLOC)
360 && strcmp(info->secstrings + shdr->sh_name, name) == 0)
361 return i;
362 }
363 return 0;
364 }
365
366 /* Find a module section, or NULL. */
section_addr(const struct load_info * info,const char * name)367 static void *section_addr(const struct load_info *info, const char *name)
368 {
369 /* Section 0 has sh_addr 0. */
370 return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
371 }
372
373 /* 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)374 static void *section_objs(const struct load_info *info,
375 const char *name,
376 size_t object_size,
377 unsigned int *num)
378 {
379 unsigned int sec = find_sec(info, name);
380
381 /* Section 0 has sh_addr 0 and sh_size 0. */
382 *num = info->sechdrs[sec].sh_size / object_size;
383 return (void *)info->sechdrs[sec].sh_addr;
384 }
385
386 /* Find a module section: 0 means not found. Ignores SHF_ALLOC flag. */
find_any_sec(const struct load_info * info,const char * name)387 static unsigned int find_any_sec(const struct load_info *info, const char *name)
388 {
389 unsigned int i;
390
391 for (i = 1; i < info->hdr->e_shnum; i++) {
392 Elf_Shdr *shdr = &info->sechdrs[i];
393 if (strcmp(info->secstrings + shdr->sh_name, name) == 0)
394 return i;
395 }
396 return 0;
397 }
398
399 /*
400 * Find a module section, or NULL. Fill in number of "objects" in section.
401 * Ignores SHF_ALLOC flag.
402 */
any_section_objs(const struct load_info * info,const char * name,size_t object_size,unsigned int * num)403 static __maybe_unused void *any_section_objs(const struct load_info *info,
404 const char *name,
405 size_t object_size,
406 unsigned int *num)
407 {
408 unsigned int sec = find_any_sec(info, name);
409
410 /* Section 0 has sh_addr 0 and sh_size 0. */
411 *num = info->sechdrs[sec].sh_size / object_size;
412 return (void *)info->sechdrs[sec].sh_addr;
413 }
414
415 /* Provided by the linker */
416 extern const struct kernel_symbol __start___ksymtab[];
417 extern const struct kernel_symbol __stop___ksymtab[];
418 extern const struct kernel_symbol __start___ksymtab_gpl[];
419 extern const struct kernel_symbol __stop___ksymtab_gpl[];
420 extern const s32 __start___kcrctab[];
421 extern const s32 __start___kcrctab_gpl[];
422
423 #ifndef CONFIG_MODVERSIONS
424 #define symversion(base, idx) NULL
425 #else
426 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
427 #endif
428
429 struct symsearch {
430 const struct kernel_symbol *start, *stop;
431 const s32 *crcs;
432 enum mod_license {
433 NOT_GPL_ONLY,
434 GPL_ONLY,
435 } license;
436 };
437
438 struct find_symbol_arg {
439 /* Input */
440 const char *name;
441 bool gplok;
442 bool warn;
443
444 /* Output */
445 struct module *owner;
446 const s32 *crc;
447 const struct kernel_symbol *sym;
448 enum mod_license license;
449 };
450
check_exported_symbol(const struct symsearch * syms,struct module * owner,unsigned int symnum,void * data)451 static bool check_exported_symbol(const struct symsearch *syms,
452 struct module *owner,
453 unsigned int symnum, void *data)
454 {
455 struct find_symbol_arg *fsa = data;
456
457 if (!fsa->gplok && syms->license == GPL_ONLY)
458 return false;
459 fsa->owner = owner;
460 fsa->crc = symversion(syms->crcs, symnum);
461 fsa->sym = &syms->start[symnum];
462 fsa->license = syms->license;
463 return true;
464 }
465
kernel_symbol_value(const struct kernel_symbol * sym)466 static unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
467 {
468 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
469 return (unsigned long)offset_to_ptr(&sym->value_offset);
470 #else
471 return sym->value;
472 #endif
473 }
474
kernel_symbol_name(const struct kernel_symbol * sym)475 static const char *kernel_symbol_name(const struct kernel_symbol *sym)
476 {
477 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
478 return offset_to_ptr(&sym->name_offset);
479 #else
480 return sym->name;
481 #endif
482 }
483
kernel_symbol_namespace(const struct kernel_symbol * sym)484 static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
485 {
486 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
487 if (!sym->namespace_offset)
488 return NULL;
489 return offset_to_ptr(&sym->namespace_offset);
490 #else
491 return sym->namespace;
492 #endif
493 }
494
cmp_name(const void * name,const void * sym)495 static int cmp_name(const void *name, const void *sym)
496 {
497 return strcmp(name, kernel_symbol_name(sym));
498 }
499
find_exported_symbol_in_section(const struct symsearch * syms,struct module * owner,void * data)500 static bool find_exported_symbol_in_section(const struct symsearch *syms,
501 struct module *owner,
502 void *data)
503 {
504 struct find_symbol_arg *fsa = data;
505 struct kernel_symbol *sym;
506
507 sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
508 sizeof(struct kernel_symbol), cmp_name);
509
510 if (sym != NULL && check_exported_symbol(syms, owner,
511 sym - syms->start, data))
512 return true;
513
514 return false;
515 }
516
517 /*
518 * Find an exported symbol and return it, along with, (optional) crc and
519 * (optional) module which owns it. Needs preempt disabled or module_mutex.
520 */
find_symbol(struct find_symbol_arg * fsa)521 static bool find_symbol(struct find_symbol_arg *fsa)
522 {
523 static const struct symsearch arr[] = {
524 { __start___ksymtab, __stop___ksymtab, __start___kcrctab,
525 NOT_GPL_ONLY },
526 { __start___ksymtab_gpl, __stop___ksymtab_gpl,
527 __start___kcrctab_gpl,
528 GPL_ONLY },
529 };
530 struct module *mod;
531 unsigned int i;
532
533 module_assert_mutex_or_preempt();
534
535 for (i = 0; i < ARRAY_SIZE(arr); i++)
536 if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
537 return true;
538
539 list_for_each_entry_rcu(mod, &modules, list,
540 lockdep_is_held(&module_mutex)) {
541 struct symsearch arr[] = {
542 { mod->syms, mod->syms + mod->num_syms, mod->crcs,
543 NOT_GPL_ONLY },
544 { mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
545 mod->gpl_crcs,
546 GPL_ONLY },
547 };
548
549 if (mod->state == MODULE_STATE_UNFORMED)
550 continue;
551
552 for (i = 0; i < ARRAY_SIZE(arr); i++)
553 if (find_exported_symbol_in_section(&arr[i], mod, fsa))
554 return true;
555 }
556
557 pr_debug("Failed to find symbol %s\n", fsa->name);
558 return false;
559 }
560
561 /*
562 * Search for module by name: must hold module_mutex (or preempt disabled
563 * for read-only access).
564 */
find_module_all(const char * name,size_t len,bool even_unformed)565 static struct module *find_module_all(const char *name, size_t len,
566 bool even_unformed)
567 {
568 struct module *mod;
569
570 module_assert_mutex_or_preempt();
571
572 list_for_each_entry_rcu(mod, &modules, list,
573 lockdep_is_held(&module_mutex)) {
574 if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
575 continue;
576 if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
577 return mod;
578 }
579 return NULL;
580 }
581
find_module(const char * name)582 struct module *find_module(const char *name)
583 {
584 return find_module_all(name, strlen(name), false);
585 }
586
587 #ifdef CONFIG_SMP
588
mod_percpu(struct module * mod)589 static inline void __percpu *mod_percpu(struct module *mod)
590 {
591 return mod->percpu;
592 }
593
percpu_modalloc(struct module * mod,struct load_info * info)594 static int percpu_modalloc(struct module *mod, struct load_info *info)
595 {
596 Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
597 unsigned long align = pcpusec->sh_addralign;
598
599 if (!pcpusec->sh_size)
600 return 0;
601
602 if (align > PAGE_SIZE) {
603 pr_warn("%s: per-cpu alignment %li > %li\n",
604 mod->name, align, PAGE_SIZE);
605 align = PAGE_SIZE;
606 }
607
608 mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
609 if (!mod->percpu) {
610 pr_warn("%s: Could not allocate %lu bytes percpu data\n",
611 mod->name, (unsigned long)pcpusec->sh_size);
612 return -ENOMEM;
613 }
614 mod->percpu_size = pcpusec->sh_size;
615 return 0;
616 }
617
percpu_modfree(struct module * mod)618 static void percpu_modfree(struct module *mod)
619 {
620 free_percpu(mod->percpu);
621 }
622
find_pcpusec(struct load_info * info)623 static unsigned int find_pcpusec(struct load_info *info)
624 {
625 return find_sec(info, ".data..percpu");
626 }
627
percpu_modcopy(struct module * mod,const void * from,unsigned long size)628 static void percpu_modcopy(struct module *mod,
629 const void *from, unsigned long size)
630 {
631 int cpu;
632
633 for_each_possible_cpu(cpu)
634 memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
635 }
636
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)637 bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
638 {
639 struct module *mod;
640 unsigned int cpu;
641
642 preempt_disable();
643
644 list_for_each_entry_rcu(mod, &modules, list) {
645 if (mod->state == MODULE_STATE_UNFORMED)
646 continue;
647 if (!mod->percpu_size)
648 continue;
649 for_each_possible_cpu(cpu) {
650 void *start = per_cpu_ptr(mod->percpu, cpu);
651 void *va = (void *)addr;
652
653 if (va >= start && va < start + mod->percpu_size) {
654 if (can_addr) {
655 *can_addr = (unsigned long) (va - start);
656 *can_addr += (unsigned long)
657 per_cpu_ptr(mod->percpu,
658 get_boot_cpu_id());
659 }
660 preempt_enable();
661 return true;
662 }
663 }
664 }
665
666 preempt_enable();
667 return false;
668 }
669
670 /**
671 * is_module_percpu_address() - test whether address is from module static percpu
672 * @addr: address to test
673 *
674 * Test whether @addr belongs to module static percpu area.
675 *
676 * Return: %true if @addr is from module static percpu area
677 */
is_module_percpu_address(unsigned long addr)678 bool is_module_percpu_address(unsigned long addr)
679 {
680 return __is_module_percpu_address(addr, NULL);
681 }
682
683 #else /* ... !CONFIG_SMP */
684
mod_percpu(struct module * mod)685 static inline void __percpu *mod_percpu(struct module *mod)
686 {
687 return NULL;
688 }
percpu_modalloc(struct module * mod,struct load_info * info)689 static int percpu_modalloc(struct module *mod, struct load_info *info)
690 {
691 /* UP modules shouldn't have this section: ENOMEM isn't quite right */
692 if (info->sechdrs[info->index.pcpu].sh_size != 0)
693 return -ENOMEM;
694 return 0;
695 }
percpu_modfree(struct module * mod)696 static inline void percpu_modfree(struct module *mod)
697 {
698 }
find_pcpusec(struct load_info * info)699 static unsigned int find_pcpusec(struct load_info *info)
700 {
701 return 0;
702 }
percpu_modcopy(struct module * mod,const void * from,unsigned long size)703 static inline void percpu_modcopy(struct module *mod,
704 const void *from, unsigned long size)
705 {
706 /* pcpusec should be 0, and size of that section should be 0. */
707 BUG_ON(size != 0);
708 }
is_module_percpu_address(unsigned long addr)709 bool is_module_percpu_address(unsigned long addr)
710 {
711 return false;
712 }
713
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)714 bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
715 {
716 return false;
717 }
718
719 #endif /* CONFIG_SMP */
720
721 #define MODINFO_ATTR(field) \
722 static void setup_modinfo_##field(struct module *mod, const char *s) \
723 { \
724 mod->field = kstrdup(s, GFP_KERNEL); \
725 } \
726 static ssize_t show_modinfo_##field(struct module_attribute *mattr, \
727 struct module_kobject *mk, char *buffer) \
728 { \
729 return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field); \
730 } \
731 static int modinfo_##field##_exists(struct module *mod) \
732 { \
733 return mod->field != NULL; \
734 } \
735 static void free_modinfo_##field(struct module *mod) \
736 { \
737 kfree(mod->field); \
738 mod->field = NULL; \
739 } \
740 static struct module_attribute modinfo_##field = { \
741 .attr = { .name = __stringify(field), .mode = 0444 }, \
742 .show = show_modinfo_##field, \
743 .setup = setup_modinfo_##field, \
744 .test = modinfo_##field##_exists, \
745 .free = free_modinfo_##field, \
746 };
747
748 MODINFO_ATTR(version);
749 MODINFO_ATTR(srcversion);
750 MODINFO_ATTR(scmversion);
751
752 static char last_unloaded_module[MODULE_NAME_LEN+1];
753
754 #ifdef CONFIG_MODULE_UNLOAD
755
756 EXPORT_TRACEPOINT_SYMBOL(module_get);
757
758 /* MODULE_REF_BASE is the base reference count by kmodule loader. */
759 #define MODULE_REF_BASE 1
760
761 /* Init the unload section of the module. */
module_unload_init(struct module * mod)762 static int module_unload_init(struct module *mod)
763 {
764 /*
765 * Initialize reference counter to MODULE_REF_BASE.
766 * refcnt == 0 means module is going.
767 */
768 atomic_set(&mod->refcnt, MODULE_REF_BASE);
769
770 INIT_LIST_HEAD(&mod->source_list);
771 INIT_LIST_HEAD(&mod->target_list);
772
773 /* Hold reference count during initialization. */
774 atomic_inc(&mod->refcnt);
775
776 return 0;
777 }
778
779 /* Does a already use b? */
already_uses(struct module * a,struct module * b)780 static int already_uses(struct module *a, struct module *b)
781 {
782 struct module_use *use;
783
784 list_for_each_entry(use, &b->source_list, source_list) {
785 if (use->source == a) {
786 pr_debug("%s uses %s!\n", a->name, b->name);
787 return 1;
788 }
789 }
790 pr_debug("%s does not use %s!\n", a->name, b->name);
791 return 0;
792 }
793
794 /*
795 * Module a uses b
796 * - we add 'a' as a "source", 'b' as a "target" of module use
797 * - the module_use is added to the list of 'b' sources (so
798 * 'b' can walk the list to see who sourced them), and of 'a'
799 * targets (so 'a' can see what modules it targets).
800 */
add_module_usage(struct module * a,struct module * b)801 static int add_module_usage(struct module *a, struct module *b)
802 {
803 struct module_use *use;
804
805 pr_debug("Allocating new usage for %s.\n", a->name);
806 use = kmalloc(sizeof(*use), GFP_ATOMIC);
807 if (!use)
808 return -ENOMEM;
809
810 use->source = a;
811 use->target = b;
812 list_add(&use->source_list, &b->source_list);
813 list_add(&use->target_list, &a->target_list);
814 return 0;
815 }
816
817 /* Module a uses b: caller needs module_mutex() */
ref_module(struct module * a,struct module * b)818 static int ref_module(struct module *a, struct module *b)
819 {
820 int err;
821
822 if (b == NULL || already_uses(a, b))
823 return 0;
824
825 /* If module isn't available, we fail. */
826 err = strong_try_module_get(b);
827 if (err)
828 return err;
829
830 err = add_module_usage(a, b);
831 if (err) {
832 module_put(b);
833 return err;
834 }
835 return 0;
836 }
837
838 /* Clear the unload stuff of the module. */
module_unload_free(struct module * mod)839 static void module_unload_free(struct module *mod)
840 {
841 struct module_use *use, *tmp;
842
843 mutex_lock(&module_mutex);
844 list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
845 struct module *i = use->target;
846 pr_debug("%s unusing %s\n", mod->name, i->name);
847 module_put(i);
848 list_del(&use->source_list);
849 list_del(&use->target_list);
850 kfree(use);
851 }
852 mutex_unlock(&module_mutex);
853 }
854
855 #ifdef CONFIG_MODULE_FORCE_UNLOAD
try_force_unload(unsigned int flags)856 static inline int try_force_unload(unsigned int flags)
857 {
858 int ret = (flags & O_TRUNC);
859 if (ret)
860 add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
861 return ret;
862 }
863 #else
try_force_unload(unsigned int flags)864 static inline int try_force_unload(unsigned int flags)
865 {
866 return 0;
867 }
868 #endif /* CONFIG_MODULE_FORCE_UNLOAD */
869
870 /* Try to release refcount of module, 0 means success. */
try_release_module_ref(struct module * mod)871 static int try_release_module_ref(struct module *mod)
872 {
873 int ret;
874
875 /* Try to decrement refcnt which we set at loading */
876 ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt);
877 BUG_ON(ret < 0);
878 if (ret)
879 /* Someone can put this right now, recover with checking */
880 ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0);
881
882 return ret;
883 }
884
try_stop_module(struct module * mod,int flags,int * forced)885 static int try_stop_module(struct module *mod, int flags, int *forced)
886 {
887 /* If it's not unused, quit unless we're forcing. */
888 if (try_release_module_ref(mod) != 0) {
889 *forced = try_force_unload(flags);
890 if (!(*forced))
891 return -EWOULDBLOCK;
892 }
893
894 /* Mark it as dying. */
895 mod->state = MODULE_STATE_GOING;
896
897 return 0;
898 }
899
900 /**
901 * module_refcount() - return the refcount or -1 if unloading
902 * @mod: the module we're checking
903 *
904 * Return:
905 * -1 if the module is in the process of unloading
906 * otherwise the number of references in the kernel to the module
907 */
module_refcount(struct module * mod)908 int module_refcount(struct module *mod)
909 {
910 return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
911 }
912 EXPORT_SYMBOL(module_refcount);
913
914 /* This exists whether we can unload or not */
915 static void free_module(struct module *mod);
916
SYSCALL_DEFINE2(delete_module,const char __user *,name_user,unsigned int,flags)917 SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
918 unsigned int, flags)
919 {
920 struct module *mod;
921 char name[MODULE_NAME_LEN];
922 int ret, forced = 0;
923
924 if (!capable(CAP_SYS_MODULE) || modules_disabled)
925 return -EPERM;
926
927 if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
928 return -EFAULT;
929 name[MODULE_NAME_LEN-1] = '\0';
930
931 audit_log_kern_module(name);
932
933 if (mutex_lock_interruptible(&module_mutex) != 0)
934 return -EINTR;
935
936 mod = find_module(name);
937 if (!mod) {
938 ret = -ENOENT;
939 goto out;
940 }
941
942 if (!list_empty(&mod->source_list)) {
943 /* Other modules depend on us: get rid of them first. */
944 ret = -EWOULDBLOCK;
945 goto out;
946 }
947
948 /* Doing init or already dying? */
949 if (mod->state != MODULE_STATE_LIVE) {
950 /* FIXME: if (force), slam module count damn the torpedoes */
951 pr_debug("%s already dying\n", mod->name);
952 ret = -EBUSY;
953 goto out;
954 }
955
956 /* If it has an init func, it must have an exit func to unload */
957 if (mod->init && !mod->exit) {
958 forced = try_force_unload(flags);
959 if (!forced) {
960 /* This module can't be removed */
961 ret = -EBUSY;
962 goto out;
963 }
964 }
965
966 /* Stop the machine so refcounts can't move and disable module. */
967 ret = try_stop_module(mod, flags, &forced);
968 if (ret != 0)
969 goto out;
970
971 mutex_unlock(&module_mutex);
972 /* Final destruction now no one is using it. */
973 if (mod->exit != NULL)
974 mod->exit();
975 blocking_notifier_call_chain(&module_notify_list,
976 MODULE_STATE_GOING, mod);
977 klp_module_going(mod);
978 ftrace_release_mod(mod);
979
980 async_synchronize_full();
981
982 /* Store the name of the last unloaded module for diagnostic purposes */
983 strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
984
985 free_module(mod);
986 /* someone could wait for the module in add_unformed_module() */
987 wake_up_all(&module_wq);
988 return 0;
989 out:
990 mutex_unlock(&module_mutex);
991 return ret;
992 }
993
print_unload_info(struct seq_file * m,struct module * mod)994 static inline void print_unload_info(struct seq_file *m, struct module *mod)
995 {
996 struct module_use *use;
997 int printed_something = 0;
998
999 seq_printf(m, " %i ", module_refcount(mod));
1000
1001 /*
1002 * Always include a trailing , so userspace can differentiate
1003 * between this and the old multi-field proc format.
1004 */
1005 list_for_each_entry(use, &mod->source_list, source_list) {
1006 printed_something = 1;
1007 seq_printf(m, "%s,", use->source->name);
1008 }
1009
1010 if (mod->init != NULL && mod->exit == NULL) {
1011 printed_something = 1;
1012 seq_puts(m, "[permanent],");
1013 }
1014
1015 if (!printed_something)
1016 seq_puts(m, "-");
1017 }
1018
__symbol_put(const char * symbol)1019 void __symbol_put(const char *symbol)
1020 {
1021 struct find_symbol_arg fsa = {
1022 .name = symbol,
1023 .gplok = true,
1024 };
1025
1026 preempt_disable();
1027 BUG_ON(!find_symbol(&fsa));
1028 module_put(fsa.owner);
1029 preempt_enable();
1030 }
1031 EXPORT_SYMBOL(__symbol_put);
1032
1033 /* Note this assumes addr is a function, which it currently always is. */
symbol_put_addr(void * addr)1034 void symbol_put_addr(void *addr)
1035 {
1036 struct module *modaddr;
1037 unsigned long a = (unsigned long)dereference_function_descriptor(addr);
1038
1039 if (core_kernel_text(a))
1040 return;
1041
1042 /*
1043 * Even though we hold a reference on the module; we still need to
1044 * disable preemption in order to safely traverse the data structure.
1045 */
1046 preempt_disable();
1047 modaddr = __module_text_address(a);
1048 BUG_ON(!modaddr);
1049 module_put(modaddr);
1050 preempt_enable();
1051 }
1052 EXPORT_SYMBOL_GPL(symbol_put_addr);
1053
show_refcnt(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1054 static ssize_t show_refcnt(struct module_attribute *mattr,
1055 struct module_kobject *mk, char *buffer)
1056 {
1057 return sprintf(buffer, "%i\n", module_refcount(mk->mod));
1058 }
1059
1060 static struct module_attribute modinfo_refcnt =
1061 __ATTR(refcnt, 0444, show_refcnt, NULL);
1062
__module_get(struct module * module)1063 void __module_get(struct module *module)
1064 {
1065 if (module) {
1066 preempt_disable();
1067 atomic_inc(&module->refcnt);
1068 trace_module_get(module, _RET_IP_);
1069 preempt_enable();
1070 }
1071 }
1072 EXPORT_SYMBOL(__module_get);
1073
try_module_get(struct module * module)1074 bool try_module_get(struct module *module)
1075 {
1076 bool ret = true;
1077
1078 if (module) {
1079 preempt_disable();
1080 /* Note: here, we can fail to get a reference */
1081 if (likely(module_is_live(module) &&
1082 atomic_inc_not_zero(&module->refcnt) != 0))
1083 trace_module_get(module, _RET_IP_);
1084 else
1085 ret = false;
1086
1087 preempt_enable();
1088 }
1089 return ret;
1090 }
1091 EXPORT_SYMBOL(try_module_get);
1092
module_put(struct module * module)1093 void module_put(struct module *module)
1094 {
1095 int ret;
1096
1097 if (module) {
1098 preempt_disable();
1099 ret = atomic_dec_if_positive(&module->refcnt);
1100 WARN_ON(ret < 0); /* Failed to put refcount */
1101 trace_module_put(module, _RET_IP_);
1102 preempt_enable();
1103 }
1104 }
1105 EXPORT_SYMBOL(module_put);
1106
1107 #else /* !CONFIG_MODULE_UNLOAD */
print_unload_info(struct seq_file * m,struct module * mod)1108 static inline void print_unload_info(struct seq_file *m, struct module *mod)
1109 {
1110 /* We don't know the usage count, or what modules are using. */
1111 seq_puts(m, " - -");
1112 }
1113
module_unload_free(struct module * mod)1114 static inline void module_unload_free(struct module *mod)
1115 {
1116 }
1117
ref_module(struct module * a,struct module * b)1118 static int ref_module(struct module *a, struct module *b)
1119 {
1120 return strong_try_module_get(b);
1121 }
1122
module_unload_init(struct module * mod)1123 static inline int module_unload_init(struct module *mod)
1124 {
1125 return 0;
1126 }
1127 #endif /* CONFIG_MODULE_UNLOAD */
1128
module_flags_taint(struct module * mod,char * buf)1129 static size_t module_flags_taint(struct module *mod, char *buf)
1130 {
1131 size_t l = 0;
1132 int i;
1133
1134 for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
1135 if (taint_flags[i].module && test_bit(i, &mod->taints))
1136 buf[l++] = taint_flags[i].c_true;
1137 }
1138
1139 return l;
1140 }
1141
show_initstate(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1142 static ssize_t show_initstate(struct module_attribute *mattr,
1143 struct module_kobject *mk, char *buffer)
1144 {
1145 const char *state = "unknown";
1146
1147 switch (mk->mod->state) {
1148 case MODULE_STATE_LIVE:
1149 state = "live";
1150 break;
1151 case MODULE_STATE_COMING:
1152 state = "coming";
1153 break;
1154 case MODULE_STATE_GOING:
1155 state = "going";
1156 break;
1157 default:
1158 BUG();
1159 }
1160 return sprintf(buffer, "%s\n", state);
1161 }
1162
1163 static struct module_attribute modinfo_initstate =
1164 __ATTR(initstate, 0444, show_initstate, NULL);
1165
store_uevent(struct module_attribute * mattr,struct module_kobject * mk,const char * buffer,size_t count)1166 static ssize_t store_uevent(struct module_attribute *mattr,
1167 struct module_kobject *mk,
1168 const char *buffer, size_t count)
1169 {
1170 int rc;
1171
1172 rc = kobject_synth_uevent(&mk->kobj, buffer, count);
1173 return rc ? rc : count;
1174 }
1175
1176 struct module_attribute module_uevent =
1177 __ATTR(uevent, 0200, NULL, store_uevent);
1178
show_coresize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1179 static ssize_t show_coresize(struct module_attribute *mattr,
1180 struct module_kobject *mk, char *buffer)
1181 {
1182 return sprintf(buffer, "%u\n", mk->mod->core_layout.size);
1183 }
1184
1185 static struct module_attribute modinfo_coresize =
1186 __ATTR(coresize, 0444, show_coresize, NULL);
1187
show_initsize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1188 static ssize_t show_initsize(struct module_attribute *mattr,
1189 struct module_kobject *mk, char *buffer)
1190 {
1191 return sprintf(buffer, "%u\n", mk->mod->init_layout.size);
1192 }
1193
1194 static struct module_attribute modinfo_initsize =
1195 __ATTR(initsize, 0444, show_initsize, NULL);
1196
show_taint(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)1197 static ssize_t show_taint(struct module_attribute *mattr,
1198 struct module_kobject *mk, char *buffer)
1199 {
1200 size_t l;
1201
1202 l = module_flags_taint(mk->mod, buffer);
1203 buffer[l++] = '\n';
1204 return l;
1205 }
1206
1207 static struct module_attribute modinfo_taint =
1208 __ATTR(taint, 0444, show_taint, NULL);
1209
1210 static struct module_attribute *modinfo_attrs[] = {
1211 &module_uevent,
1212 &modinfo_version,
1213 &modinfo_srcversion,
1214 &modinfo_scmversion,
1215 &modinfo_initstate,
1216 &modinfo_coresize,
1217 &modinfo_initsize,
1218 &modinfo_taint,
1219 #ifdef CONFIG_MODULE_UNLOAD
1220 &modinfo_refcnt,
1221 #endif
1222 NULL,
1223 };
1224
1225 static const char vermagic[] = VERMAGIC_STRING;
1226
try_to_force_load(struct module * mod,const char * reason)1227 static int try_to_force_load(struct module *mod, const char *reason)
1228 {
1229 #ifdef CONFIG_MODULE_FORCE_LOAD
1230 if (!test_taint(TAINT_FORCED_MODULE))
1231 pr_warn("%s: %s: kernel tainted.\n", mod->name, reason);
1232 add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
1233 return 0;
1234 #else
1235 return -ENOEXEC;
1236 #endif
1237 }
1238
1239 #ifdef CONFIG_MODVERSIONS
1240
resolve_rel_crc(const s32 * crc)1241 static u32 resolve_rel_crc(const s32 *crc)
1242 {
1243 return *(u32 *)((void *)crc + *crc);
1244 }
1245
check_version(const struct load_info * info,const char * symname,struct module * mod,const s32 * crc)1246 static int check_version(const struct load_info *info,
1247 const char *symname,
1248 struct module *mod,
1249 const s32 *crc)
1250 {
1251 Elf_Shdr *sechdrs = info->sechdrs;
1252 unsigned int versindex = info->index.vers;
1253 unsigned int i, num_versions;
1254 struct modversion_info *versions;
1255
1256 /* Exporting module didn't supply crcs? OK, we're already tainted. */
1257 if (!crc)
1258 return 1;
1259
1260 /* No versions at all? modprobe --force does this. */
1261 if (versindex == 0)
1262 return try_to_force_load(mod, symname) == 0;
1263
1264 versions = (void *) sechdrs[versindex].sh_addr;
1265 num_versions = sechdrs[versindex].sh_size
1266 / sizeof(struct modversion_info);
1267
1268 for (i = 0; i < num_versions; i++) {
1269 u32 crcval;
1270
1271 if (strcmp(versions[i].name, symname) != 0)
1272 continue;
1273
1274 if (IS_ENABLED(CONFIG_MODULE_REL_CRCS))
1275 crcval = resolve_rel_crc(crc);
1276 else
1277 crcval = *crc;
1278 if (versions[i].crc == crcval)
1279 return 1;
1280 pr_debug("Found checksum %X vs module %lX\n",
1281 crcval, versions[i].crc);
1282 goto bad_version;
1283 }
1284
1285 /* Broken toolchain. Warn once, then let it go.. */
1286 pr_warn_once("%s: no symbol version for %s\n", info->name, symname);
1287 return 1;
1288
1289 bad_version:
1290 pr_warn("%s: disagrees about version of symbol %s\n",
1291 info->name, symname);
1292 return 0;
1293 }
1294
check_modstruct_version(const struct load_info * info,struct module * mod)1295 static inline int check_modstruct_version(const struct load_info *info,
1296 struct module *mod)
1297 {
1298 struct find_symbol_arg fsa = {
1299 .name = "module_layout",
1300 .gplok = true,
1301 };
1302
1303 /*
1304 * Since this should be found in kernel (which can't be removed), no
1305 * locking is necessary -- use preempt_disable() to placate lockdep.
1306 */
1307 preempt_disable();
1308 if (!find_symbol(&fsa)) {
1309 preempt_enable();
1310 BUG();
1311 }
1312 preempt_enable();
1313 return check_version(info, "module_layout", mod, fsa.crc);
1314 }
1315
1316 /* First part is kernel version, which we ignore if module has crcs. */
same_magic(const char * amagic,const char * bmagic,bool has_crcs)1317 static inline int same_magic(const char *amagic, const char *bmagic,
1318 bool has_crcs)
1319 {
1320 if (has_crcs) {
1321 amagic += strcspn(amagic, " ");
1322 bmagic += strcspn(bmagic, " ");
1323 }
1324 return strcmp(amagic, bmagic) == 0;
1325 }
1326 #else
check_version(const struct load_info * info,const char * symname,struct module * mod,const s32 * crc)1327 static inline int check_version(const struct load_info *info,
1328 const char *symname,
1329 struct module *mod,
1330 const s32 *crc)
1331 {
1332 return 1;
1333 }
1334
check_modstruct_version(const struct load_info * info,struct module * mod)1335 static inline int check_modstruct_version(const struct load_info *info,
1336 struct module *mod)
1337 {
1338 return 1;
1339 }
1340
same_magic(const char * amagic,const char * bmagic,bool has_crcs)1341 static inline int same_magic(const char *amagic, const char *bmagic,
1342 bool has_crcs)
1343 {
1344 return strcmp(amagic, bmagic) == 0;
1345 }
1346 #endif /* CONFIG_MODVERSIONS */
1347
1348 static char *get_modinfo(const struct load_info *info, const char *tag);
1349 static char *get_next_modinfo(const struct load_info *info, const char *tag,
1350 char *prev);
1351
verify_namespace_is_imported(const struct load_info * info,const struct kernel_symbol * sym,struct module * mod)1352 static int verify_namespace_is_imported(const struct load_info *info,
1353 const struct kernel_symbol *sym,
1354 struct module *mod)
1355 {
1356 const char *namespace;
1357 char *imported_namespace;
1358
1359 namespace = kernel_symbol_namespace(sym);
1360 if (namespace && namespace[0]) {
1361 imported_namespace = get_modinfo(info, "import_ns");
1362 while (imported_namespace) {
1363 if (strcmp(namespace, imported_namespace) == 0)
1364 return 0;
1365 imported_namespace = get_next_modinfo(
1366 info, "import_ns", imported_namespace);
1367 }
1368 #ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1369 pr_warn(
1370 #else
1371 pr_err(
1372 #endif
1373 "%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
1374 mod->name, kernel_symbol_name(sym), namespace);
1375 #ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1376 return -EINVAL;
1377 #endif
1378 }
1379 return 0;
1380 }
1381
inherit_taint(struct module * mod,struct module * owner,const char * name)1382 static bool inherit_taint(struct module *mod, struct module *owner, const char *name)
1383 {
1384 if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
1385 return true;
1386
1387 if (mod->using_gplonly_symbols) {
1388 pr_err("%s: module using GPL-only symbols uses symbols %s from proprietary module %s.\n",
1389 mod->name, name, owner->name);
1390 return false;
1391 }
1392
1393 if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
1394 pr_warn("%s: module uses symbols %s from proprietary module %s, inheriting taint.\n",
1395 mod->name, name, owner->name);
1396 set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
1397 }
1398 return true;
1399 }
1400
1401 /* 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[])1402 static const struct kernel_symbol *resolve_symbol(struct module *mod,
1403 const struct load_info *info,
1404 const char *name,
1405 char ownername[])
1406 {
1407 struct find_symbol_arg fsa = {
1408 .name = name,
1409 .gplok = !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
1410 .warn = true,
1411 };
1412 int err;
1413
1414 /*
1415 * The module_mutex should not be a heavily contended lock;
1416 * if we get the occasional sleep here, we'll go an extra iteration
1417 * in the wait_event_interruptible(), which is harmless.
1418 */
1419 sched_annotate_sleep();
1420 mutex_lock(&module_mutex);
1421 if (!find_symbol(&fsa))
1422 goto unlock;
1423
1424 if (fsa.license == GPL_ONLY)
1425 mod->using_gplonly_symbols = true;
1426
1427 if (!inherit_taint(mod, fsa.owner, name)) {
1428 fsa.sym = NULL;
1429 goto getname;
1430 }
1431
1432 if (!check_version(info, name, mod, fsa.crc)) {
1433 fsa.sym = ERR_PTR(-EINVAL);
1434 goto getname;
1435 }
1436
1437 err = verify_namespace_is_imported(info, fsa.sym, mod);
1438 if (err) {
1439 fsa.sym = ERR_PTR(err);
1440 goto getname;
1441 }
1442
1443 err = ref_module(mod, fsa.owner);
1444 if (err) {
1445 fsa.sym = ERR_PTR(err);
1446 goto getname;
1447 }
1448
1449 getname:
1450 /* We must make copy under the lock if we failed to get ref. */
1451 strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
1452 unlock:
1453 mutex_unlock(&module_mutex);
1454 return fsa.sym;
1455 }
1456
1457 static const struct kernel_symbol *
resolve_symbol_wait(struct module * mod,const struct load_info * info,const char * name)1458 resolve_symbol_wait(struct module *mod,
1459 const struct load_info *info,
1460 const char *name)
1461 {
1462 const struct kernel_symbol *ksym;
1463 char owner[MODULE_NAME_LEN];
1464
1465 if (wait_event_interruptible_timeout(module_wq,
1466 !IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
1467 || PTR_ERR(ksym) != -EBUSY,
1468 30 * HZ) <= 0) {
1469 pr_warn("%s: gave up waiting for init of module %s.\n",
1470 mod->name, owner);
1471 }
1472 return ksym;
1473 }
1474
1475 #ifdef CONFIG_KALLSYMS
sect_empty(const Elf_Shdr * sect)1476 static inline bool sect_empty(const Elf_Shdr *sect)
1477 {
1478 return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
1479 }
1480 #endif
1481
1482 /*
1483 * /sys/module/foo/sections stuff
1484 * J. Corbet <corbet@lwn.net>
1485 */
1486 #ifdef CONFIG_SYSFS
1487
1488 #ifdef CONFIG_KALLSYMS
1489 struct module_sect_attr {
1490 struct bin_attribute battr;
1491 unsigned long address;
1492 };
1493
1494 struct module_sect_attrs {
1495 struct attribute_group grp;
1496 unsigned int nsections;
1497 struct module_sect_attr attrs[];
1498 };
1499
1500 #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)1501 static ssize_t module_sect_read(struct file *file, struct kobject *kobj,
1502 struct bin_attribute *battr,
1503 char *buf, loff_t pos, size_t count)
1504 {
1505 struct module_sect_attr *sattr =
1506 container_of(battr, struct module_sect_attr, battr);
1507 char bounce[MODULE_SECT_READ_SIZE + 1];
1508 size_t wrote;
1509
1510 if (pos != 0)
1511 return -EINVAL;
1512
1513 /*
1514 * Since we're a binary read handler, we must account for the
1515 * trailing NUL byte that sprintf will write: if "buf" is
1516 * too small to hold the NUL, or the NUL is exactly the last
1517 * byte, the read will look like it got truncated by one byte.
1518 * Since there is no way to ask sprintf nicely to not write
1519 * the NUL, we have to use a bounce buffer.
1520 */
1521 wrote = scnprintf(bounce, sizeof(bounce), "0x%px\n",
1522 kallsyms_show_value(file->f_cred)
1523 ? (void *)sattr->address : NULL);
1524 count = min(count, wrote);
1525 memcpy(buf, bounce, count);
1526
1527 return count;
1528 }
1529
free_sect_attrs(struct module_sect_attrs * sect_attrs)1530 static void free_sect_attrs(struct module_sect_attrs *sect_attrs)
1531 {
1532 unsigned int section;
1533
1534 for (section = 0; section < sect_attrs->nsections; section++)
1535 kfree(sect_attrs->attrs[section].battr.attr.name);
1536 kfree(sect_attrs);
1537 }
1538
add_sect_attrs(struct module * mod,const struct load_info * info)1539 static void add_sect_attrs(struct module *mod, const struct load_info *info)
1540 {
1541 unsigned int nloaded = 0, i, size[2];
1542 struct module_sect_attrs *sect_attrs;
1543 struct module_sect_attr *sattr;
1544 struct bin_attribute **gattr;
1545
1546 /* Count loaded sections and allocate structures */
1547 for (i = 0; i < info->hdr->e_shnum; i++)
1548 if (!sect_empty(&info->sechdrs[i]))
1549 nloaded++;
1550 size[0] = ALIGN(struct_size(sect_attrs, attrs, nloaded),
1551 sizeof(sect_attrs->grp.bin_attrs[0]));
1552 size[1] = (nloaded + 1) * sizeof(sect_attrs->grp.bin_attrs[0]);
1553 sect_attrs = kzalloc(size[0] + size[1], GFP_KERNEL);
1554 if (sect_attrs == NULL)
1555 return;
1556
1557 /* Setup section attributes. */
1558 sect_attrs->grp.name = "sections";
1559 sect_attrs->grp.bin_attrs = (void *)sect_attrs + size[0];
1560
1561 sect_attrs->nsections = 0;
1562 sattr = §_attrs->attrs[0];
1563 gattr = §_attrs->grp.bin_attrs[0];
1564 for (i = 0; i < info->hdr->e_shnum; i++) {
1565 Elf_Shdr *sec = &info->sechdrs[i];
1566 if (sect_empty(sec))
1567 continue;
1568 sysfs_bin_attr_init(&sattr->battr);
1569 sattr->address = sec->sh_addr;
1570 sattr->battr.attr.name =
1571 kstrdup(info->secstrings + sec->sh_name, GFP_KERNEL);
1572 if (sattr->battr.attr.name == NULL)
1573 goto out;
1574 sect_attrs->nsections++;
1575 sattr->battr.read = module_sect_read;
1576 sattr->battr.size = MODULE_SECT_READ_SIZE;
1577 sattr->battr.attr.mode = 0400;
1578 *(gattr++) = &(sattr++)->battr;
1579 }
1580 *gattr = NULL;
1581
1582 if (sysfs_create_group(&mod->mkobj.kobj, §_attrs->grp))
1583 goto out;
1584
1585 mod->sect_attrs = sect_attrs;
1586 return;
1587 out:
1588 free_sect_attrs(sect_attrs);
1589 }
1590
remove_sect_attrs(struct module * mod)1591 static void remove_sect_attrs(struct module *mod)
1592 {
1593 if (mod->sect_attrs) {
1594 sysfs_remove_group(&mod->mkobj.kobj,
1595 &mod->sect_attrs->grp);
1596 /*
1597 * We are positive that no one is using any sect attrs
1598 * at this point. Deallocate immediately.
1599 */
1600 free_sect_attrs(mod->sect_attrs);
1601 mod->sect_attrs = NULL;
1602 }
1603 }
1604
1605 /*
1606 * /sys/module/foo/notes/.section.name gives contents of SHT_NOTE sections.
1607 */
1608
1609 struct module_notes_attrs {
1610 struct kobject *dir;
1611 unsigned int notes;
1612 struct bin_attribute attrs[];
1613 };
1614
module_notes_read(struct file * filp,struct kobject * kobj,struct bin_attribute * bin_attr,char * buf,loff_t pos,size_t count)1615 static ssize_t module_notes_read(struct file *filp, struct kobject *kobj,
1616 struct bin_attribute *bin_attr,
1617 char *buf, loff_t pos, size_t count)
1618 {
1619 /*
1620 * The caller checked the pos and count against our size.
1621 */
1622 memcpy(buf, bin_attr->private + pos, count);
1623 return count;
1624 }
1625
free_notes_attrs(struct module_notes_attrs * notes_attrs,unsigned int i)1626 static void free_notes_attrs(struct module_notes_attrs *notes_attrs,
1627 unsigned int i)
1628 {
1629 if (notes_attrs->dir) {
1630 while (i-- > 0)
1631 sysfs_remove_bin_file(notes_attrs->dir,
1632 ¬es_attrs->attrs[i]);
1633 kobject_put(notes_attrs->dir);
1634 }
1635 kfree(notes_attrs);
1636 }
1637
add_notes_attrs(struct module * mod,const struct load_info * info)1638 static void add_notes_attrs(struct module *mod, const struct load_info *info)
1639 {
1640 unsigned int notes, loaded, i;
1641 struct module_notes_attrs *notes_attrs;
1642 struct bin_attribute *nattr;
1643
1644 /* failed to create section attributes, so can't create notes */
1645 if (!mod->sect_attrs)
1646 return;
1647
1648 /* Count notes sections and allocate structures. */
1649 notes = 0;
1650 for (i = 0; i < info->hdr->e_shnum; i++)
1651 if (!sect_empty(&info->sechdrs[i]) &&
1652 (info->sechdrs[i].sh_type == SHT_NOTE))
1653 ++notes;
1654
1655 if (notes == 0)
1656 return;
1657
1658 notes_attrs = kzalloc(struct_size(notes_attrs, attrs, notes),
1659 GFP_KERNEL);
1660 if (notes_attrs == NULL)
1661 return;
1662
1663 notes_attrs->notes = notes;
1664 nattr = ¬es_attrs->attrs[0];
1665 for (loaded = i = 0; i < info->hdr->e_shnum; ++i) {
1666 if (sect_empty(&info->sechdrs[i]))
1667 continue;
1668 if (info->sechdrs[i].sh_type == SHT_NOTE) {
1669 sysfs_bin_attr_init(nattr);
1670 nattr->attr.name = mod->sect_attrs->attrs[loaded].battr.attr.name;
1671 nattr->attr.mode = S_IRUGO;
1672 nattr->size = info->sechdrs[i].sh_size;
1673 nattr->private = (void *) info->sechdrs[i].sh_addr;
1674 nattr->read = module_notes_read;
1675 ++nattr;
1676 }
1677 ++loaded;
1678 }
1679
1680 notes_attrs->dir = kobject_create_and_add("notes", &mod->mkobj.kobj);
1681 if (!notes_attrs->dir)
1682 goto out;
1683
1684 for (i = 0; i < notes; ++i)
1685 if (sysfs_create_bin_file(notes_attrs->dir,
1686 ¬es_attrs->attrs[i]))
1687 goto out;
1688
1689 mod->notes_attrs = notes_attrs;
1690 return;
1691
1692 out:
1693 free_notes_attrs(notes_attrs, i);
1694 }
1695
remove_notes_attrs(struct module * mod)1696 static void remove_notes_attrs(struct module *mod)
1697 {
1698 if (mod->notes_attrs)
1699 free_notes_attrs(mod->notes_attrs, mod->notes_attrs->notes);
1700 }
1701
1702 #else
1703
add_sect_attrs(struct module * mod,const struct load_info * info)1704 static inline void add_sect_attrs(struct module *mod,
1705 const struct load_info *info)
1706 {
1707 }
1708
remove_sect_attrs(struct module * mod)1709 static inline void remove_sect_attrs(struct module *mod)
1710 {
1711 }
1712
add_notes_attrs(struct module * mod,const struct load_info * info)1713 static inline void add_notes_attrs(struct module *mod,
1714 const struct load_info *info)
1715 {
1716 }
1717
remove_notes_attrs(struct module * mod)1718 static inline void remove_notes_attrs(struct module *mod)
1719 {
1720 }
1721 #endif /* CONFIG_KALLSYMS */
1722
del_usage_links(struct module * mod)1723 static void del_usage_links(struct module *mod)
1724 {
1725 #ifdef CONFIG_MODULE_UNLOAD
1726 struct module_use *use;
1727
1728 mutex_lock(&module_mutex);
1729 list_for_each_entry(use, &mod->target_list, target_list)
1730 sysfs_remove_link(use->target->holders_dir, mod->name);
1731 mutex_unlock(&module_mutex);
1732 #endif
1733 }
1734
add_usage_links(struct module * mod)1735 static int add_usage_links(struct module *mod)
1736 {
1737 int ret = 0;
1738 #ifdef CONFIG_MODULE_UNLOAD
1739 struct module_use *use;
1740
1741 mutex_lock(&module_mutex);
1742 list_for_each_entry(use, &mod->target_list, target_list) {
1743 ret = sysfs_create_link(use->target->holders_dir,
1744 &mod->mkobj.kobj, mod->name);
1745 if (ret)
1746 break;
1747 }
1748 mutex_unlock(&module_mutex);
1749 if (ret)
1750 del_usage_links(mod);
1751 #endif
1752 return ret;
1753 }
1754
1755 static void module_remove_modinfo_attrs(struct module *mod, int end);
1756
module_add_modinfo_attrs(struct module * mod)1757 static int module_add_modinfo_attrs(struct module *mod)
1758 {
1759 struct module_attribute *attr;
1760 struct module_attribute *temp_attr;
1761 int error = 0;
1762 int i;
1763
1764 mod->modinfo_attrs = kzalloc((sizeof(struct module_attribute) *
1765 (ARRAY_SIZE(modinfo_attrs) + 1)),
1766 GFP_KERNEL);
1767 if (!mod->modinfo_attrs)
1768 return -ENOMEM;
1769
1770 temp_attr = mod->modinfo_attrs;
1771 for (i = 0; (attr = modinfo_attrs[i]); i++) {
1772 if (!attr->test || attr->test(mod)) {
1773 memcpy(temp_attr, attr, sizeof(*temp_attr));
1774 sysfs_attr_init(&temp_attr->attr);
1775 error = sysfs_create_file(&mod->mkobj.kobj,
1776 &temp_attr->attr);
1777 if (error)
1778 goto error_out;
1779 ++temp_attr;
1780 }
1781 }
1782
1783 return 0;
1784
1785 error_out:
1786 if (i > 0)
1787 module_remove_modinfo_attrs(mod, --i);
1788 else
1789 kfree(mod->modinfo_attrs);
1790 return error;
1791 }
1792
module_remove_modinfo_attrs(struct module * mod,int end)1793 static void module_remove_modinfo_attrs(struct module *mod, int end)
1794 {
1795 struct module_attribute *attr;
1796 int i;
1797
1798 for (i = 0; (attr = &mod->modinfo_attrs[i]); i++) {
1799 if (end >= 0 && i > end)
1800 break;
1801 /* pick a field to test for end of list */
1802 if (!attr->attr.name)
1803 break;
1804 sysfs_remove_file(&mod->mkobj.kobj, &attr->attr);
1805 if (attr->free)
1806 attr->free(mod);
1807 }
1808 kfree(mod->modinfo_attrs);
1809 }
1810
mod_kobject_put(struct module * mod)1811 static void mod_kobject_put(struct module *mod)
1812 {
1813 DECLARE_COMPLETION_ONSTACK(c);
1814 mod->mkobj.kobj_completion = &c;
1815 kobject_put(&mod->mkobj.kobj);
1816 wait_for_completion(&c);
1817 }
1818
mod_sysfs_init(struct module * mod)1819 static int mod_sysfs_init(struct module *mod)
1820 {
1821 int err;
1822 struct kobject *kobj;
1823
1824 if (!module_sysfs_initialized) {
1825 pr_err("%s: module sysfs not initialized\n", mod->name);
1826 err = -EINVAL;
1827 goto out;
1828 }
1829
1830 kobj = kset_find_obj(module_kset, mod->name);
1831 if (kobj) {
1832 pr_err("%s: module is already loaded\n", mod->name);
1833 kobject_put(kobj);
1834 err = -EINVAL;
1835 goto out;
1836 }
1837
1838 mod->mkobj.mod = mod;
1839
1840 memset(&mod->mkobj.kobj, 0, sizeof(mod->mkobj.kobj));
1841 mod->mkobj.kobj.kset = module_kset;
1842 err = kobject_init_and_add(&mod->mkobj.kobj, &module_ktype, NULL,
1843 "%s", mod->name);
1844 if (err)
1845 mod_kobject_put(mod);
1846
1847 out:
1848 return err;
1849 }
1850
mod_sysfs_setup(struct module * mod,const struct load_info * info,struct kernel_param * kparam,unsigned int num_params)1851 static int mod_sysfs_setup(struct module *mod,
1852 const struct load_info *info,
1853 struct kernel_param *kparam,
1854 unsigned int num_params)
1855 {
1856 int err;
1857
1858 err = mod_sysfs_init(mod);
1859 if (err)
1860 goto out;
1861
1862 mod->holders_dir = kobject_create_and_add("holders", &mod->mkobj.kobj);
1863 if (!mod->holders_dir) {
1864 err = -ENOMEM;
1865 goto out_unreg;
1866 }
1867
1868 err = module_param_sysfs_setup(mod, kparam, num_params);
1869 if (err)
1870 goto out_unreg_holders;
1871
1872 err = module_add_modinfo_attrs(mod);
1873 if (err)
1874 goto out_unreg_param;
1875
1876 err = add_usage_links(mod);
1877 if (err)
1878 goto out_unreg_modinfo_attrs;
1879
1880 add_sect_attrs(mod, info);
1881 add_notes_attrs(mod, info);
1882
1883 return 0;
1884
1885 out_unreg_modinfo_attrs:
1886 module_remove_modinfo_attrs(mod, -1);
1887 out_unreg_param:
1888 module_param_sysfs_remove(mod);
1889 out_unreg_holders:
1890 kobject_put(mod->holders_dir);
1891 out_unreg:
1892 mod_kobject_put(mod);
1893 out:
1894 return err;
1895 }
1896
mod_sysfs_fini(struct module * mod)1897 static void mod_sysfs_fini(struct module *mod)
1898 {
1899 remove_notes_attrs(mod);
1900 remove_sect_attrs(mod);
1901 mod_kobject_put(mod);
1902 }
1903
init_param_lock(struct module * mod)1904 static void init_param_lock(struct module *mod)
1905 {
1906 mutex_init(&mod->param_lock);
1907 }
1908 #else /* !CONFIG_SYSFS */
1909
mod_sysfs_setup(struct module * mod,const struct load_info * info,struct kernel_param * kparam,unsigned int num_params)1910 static int mod_sysfs_setup(struct module *mod,
1911 const struct load_info *info,
1912 struct kernel_param *kparam,
1913 unsigned int num_params)
1914 {
1915 return 0;
1916 }
1917
mod_sysfs_fini(struct module * mod)1918 static void mod_sysfs_fini(struct module *mod)
1919 {
1920 }
1921
module_remove_modinfo_attrs(struct module * mod,int end)1922 static void module_remove_modinfo_attrs(struct module *mod, int end)
1923 {
1924 }
1925
del_usage_links(struct module * mod)1926 static void del_usage_links(struct module *mod)
1927 {
1928 }
1929
init_param_lock(struct module * mod)1930 static void init_param_lock(struct module *mod)
1931 {
1932 }
1933 #endif /* CONFIG_SYSFS */
1934
mod_sysfs_teardown(struct module * mod)1935 static void mod_sysfs_teardown(struct module *mod)
1936 {
1937 del_usage_links(mod);
1938 module_remove_modinfo_attrs(mod, -1);
1939 module_param_sysfs_remove(mod);
1940 kobject_put(mod->mkobj.drivers_dir);
1941 kobject_put(mod->holders_dir);
1942 mod_sysfs_fini(mod);
1943 }
1944
1945 /*
1946 * LKM RO/NX protection: protect module's text/ro-data
1947 * from modification and any data from execution.
1948 *
1949 * General layout of module is:
1950 * [text] [read-only-data] [ro-after-init] [writable data]
1951 * text_size -----^ ^ ^ ^
1952 * ro_size ------------------------| | |
1953 * ro_after_init_size -----------------------------| |
1954 * size -----------------------------------------------------------|
1955 *
1956 * These values are always page-aligned (as is base)
1957 */
1958
1959 /*
1960 * Since some arches are moving towards PAGE_KERNEL module allocations instead
1961 * of PAGE_KERNEL_EXEC, keep frob_text() and module_enable_x() outside of the
1962 * CONFIG_STRICT_MODULE_RWX block below because they are needed regardless of
1963 * whether we are strict.
1964 */
1965 #ifdef CONFIG_ARCH_HAS_STRICT_MODULE_RWX
frob_text(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))1966 static void frob_text(const struct module_layout *layout,
1967 int (*set_memory)(unsigned long start, int num_pages))
1968 {
1969 BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
1970 BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1));
1971 set_memory((unsigned long)layout->base,
1972 layout->text_size >> PAGE_SHIFT);
1973 }
1974
module_enable_x(const struct module * mod)1975 static void module_enable_x(const struct module *mod)
1976 {
1977 frob_text(&mod->core_layout, set_memory_x);
1978 frob_text(&mod->init_layout, set_memory_x);
1979 }
1980 #else /* !CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
module_enable_x(const struct module * mod)1981 static void module_enable_x(const struct module *mod) { }
1982 #endif /* CONFIG_ARCH_HAS_STRICT_MODULE_RWX */
1983
1984 #ifdef CONFIG_STRICT_MODULE_RWX
frob_rodata(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))1985 static void frob_rodata(const struct module_layout *layout,
1986 int (*set_memory)(unsigned long start, int num_pages))
1987 {
1988 BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
1989 BUG_ON((unsigned long)layout->text_size & (PAGE_SIZE-1));
1990 BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
1991 set_memory((unsigned long)layout->base + layout->text_size,
1992 (layout->ro_size - layout->text_size) >> PAGE_SHIFT);
1993 }
1994
frob_ro_after_init(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))1995 static void frob_ro_after_init(const struct module_layout *layout,
1996 int (*set_memory)(unsigned long start, int num_pages))
1997 {
1998 BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
1999 BUG_ON((unsigned long)layout->ro_size & (PAGE_SIZE-1));
2000 BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
2001 set_memory((unsigned long)layout->base + layout->ro_size,
2002 (layout->ro_after_init_size - layout->ro_size) >> PAGE_SHIFT);
2003 }
2004
frob_writable_data(const struct module_layout * layout,int (* set_memory)(unsigned long start,int num_pages))2005 static void frob_writable_data(const struct module_layout *layout,
2006 int (*set_memory)(unsigned long start, int num_pages))
2007 {
2008 BUG_ON((unsigned long)layout->base & (PAGE_SIZE-1));
2009 BUG_ON((unsigned long)layout->ro_after_init_size & (PAGE_SIZE-1));
2010 BUG_ON((unsigned long)layout->size & (PAGE_SIZE-1));
2011 set_memory((unsigned long)layout->base + layout->ro_after_init_size,
2012 (layout->size - layout->ro_after_init_size) >> PAGE_SHIFT);
2013 }
2014
module_enable_ro(const struct module * mod,bool after_init)2015 static void module_enable_ro(const struct module *mod, bool after_init)
2016 {
2017 if (!rodata_enabled)
2018 return;
2019
2020 set_vm_flush_reset_perms(mod->core_layout.base);
2021 set_vm_flush_reset_perms(mod->init_layout.base);
2022 frob_text(&mod->core_layout, set_memory_ro);
2023
2024 frob_rodata(&mod->core_layout, set_memory_ro);
2025 frob_text(&mod->init_layout, set_memory_ro);
2026 frob_rodata(&mod->init_layout, set_memory_ro);
2027
2028 if (after_init)
2029 frob_ro_after_init(&mod->core_layout, set_memory_ro);
2030 }
2031
module_enable_nx(const struct module * mod)2032 static void module_enable_nx(const struct module *mod)
2033 {
2034 frob_rodata(&mod->core_layout, set_memory_nx);
2035 frob_ro_after_init(&mod->core_layout, set_memory_nx);
2036 frob_writable_data(&mod->core_layout, set_memory_nx);
2037 frob_rodata(&mod->init_layout, set_memory_nx);
2038 frob_writable_data(&mod->init_layout, set_memory_nx);
2039 }
2040
module_enforce_rwx_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)2041 static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
2042 char *secstrings, struct module *mod)
2043 {
2044 const unsigned long shf_wx = SHF_WRITE|SHF_EXECINSTR;
2045 int i;
2046
2047 for (i = 0; i < hdr->e_shnum; i++) {
2048 if ((sechdrs[i].sh_flags & shf_wx) == shf_wx) {
2049 pr_err("%s: section %s (index %d) has invalid WRITE|EXEC flags\n",
2050 mod->name, secstrings + sechdrs[i].sh_name, i);
2051 return -ENOEXEC;
2052 }
2053 }
2054
2055 return 0;
2056 }
2057
2058 #else /* !CONFIG_STRICT_MODULE_RWX */
module_enable_nx(const struct module * mod)2059 static void module_enable_nx(const struct module *mod) { }
module_enable_ro(const struct module * mod,bool after_init)2060 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)2061 static int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
2062 char *secstrings, struct module *mod)
2063 {
2064 return 0;
2065 }
2066 #endif /* CONFIG_STRICT_MODULE_RWX */
2067
2068 #ifdef CONFIG_LIVEPATCH
2069 /*
2070 * Persist Elf information about a module. Copy the Elf header,
2071 * section header table, section string table, and symtab section
2072 * index from info to mod->klp_info.
2073 */
copy_module_elf(struct module * mod,struct load_info * info)2074 static int copy_module_elf(struct module *mod, struct load_info *info)
2075 {
2076 unsigned int size, symndx;
2077 int ret;
2078
2079 size = sizeof(*mod->klp_info);
2080 mod->klp_info = kmalloc(size, GFP_KERNEL);
2081 if (mod->klp_info == NULL)
2082 return -ENOMEM;
2083
2084 /* Elf header */
2085 size = sizeof(mod->klp_info->hdr);
2086 memcpy(&mod->klp_info->hdr, info->hdr, size);
2087
2088 /* Elf section header table */
2089 size = sizeof(*info->sechdrs) * info->hdr->e_shnum;
2090 mod->klp_info->sechdrs = kmemdup(info->sechdrs, size, GFP_KERNEL);
2091 if (mod->klp_info->sechdrs == NULL) {
2092 ret = -ENOMEM;
2093 goto free_info;
2094 }
2095
2096 /* Elf section name string table */
2097 size = info->sechdrs[info->hdr->e_shstrndx].sh_size;
2098 mod->klp_info->secstrings = kmemdup(info->secstrings, size, GFP_KERNEL);
2099 if (mod->klp_info->secstrings == NULL) {
2100 ret = -ENOMEM;
2101 goto free_sechdrs;
2102 }
2103
2104 /* Elf symbol section index */
2105 symndx = info->index.sym;
2106 mod->klp_info->symndx = symndx;
2107
2108 /*
2109 * For livepatch modules, core_kallsyms.symtab is a complete
2110 * copy of the original symbol table. Adjust sh_addr to point
2111 * to core_kallsyms.symtab since the copy of the symtab in module
2112 * init memory is freed at the end of do_init_module().
2113 */
2114 mod->klp_info->sechdrs[symndx].sh_addr = \
2115 (unsigned long) mod->core_kallsyms.symtab;
2116
2117 return 0;
2118
2119 free_sechdrs:
2120 kfree(mod->klp_info->sechdrs);
2121 free_info:
2122 kfree(mod->klp_info);
2123 return ret;
2124 }
2125
free_module_elf(struct module * mod)2126 static void free_module_elf(struct module *mod)
2127 {
2128 kfree(mod->klp_info->sechdrs);
2129 kfree(mod->klp_info->secstrings);
2130 kfree(mod->klp_info);
2131 }
2132 #else /* !CONFIG_LIVEPATCH */
copy_module_elf(struct module * mod,struct load_info * info)2133 static int copy_module_elf(struct module *mod, struct load_info *info)
2134 {
2135 return 0;
2136 }
2137
free_module_elf(struct module * mod)2138 static void free_module_elf(struct module *mod)
2139 {
2140 }
2141 #endif /* CONFIG_LIVEPATCH */
2142
module_memfree(void * module_region)2143 void __weak module_memfree(void *module_region)
2144 {
2145 /*
2146 * This memory may be RO, and freeing RO memory in an interrupt is not
2147 * supported by vmalloc.
2148 */
2149 WARN_ON(in_interrupt());
2150 vfree(module_region);
2151 }
2152
module_arch_cleanup(struct module * mod)2153 void __weak module_arch_cleanup(struct module *mod)
2154 {
2155 }
2156
module_arch_freeing_init(struct module * mod)2157 void __weak module_arch_freeing_init(struct module *mod)
2158 {
2159 }
2160
2161 static void cfi_cleanup(struct module *mod);
2162
2163 /* Free a module, remove from lists, etc. */
free_module(struct module * mod)2164 static void free_module(struct module *mod)
2165 {
2166 trace_module_free(mod);
2167
2168 mod_sysfs_teardown(mod);
2169
2170 /*
2171 * We leave it in list to prevent duplicate loads, but make sure
2172 * that noone uses it while it's being deconstructed.
2173 */
2174 mutex_lock(&module_mutex);
2175 mod->state = MODULE_STATE_UNFORMED;
2176 mutex_unlock(&module_mutex);
2177
2178 /* Remove dynamic debug info */
2179 ddebug_remove_module(mod->name);
2180
2181 /* Arch-specific cleanup. */
2182 module_arch_cleanup(mod);
2183
2184 /* Module unload stuff */
2185 module_unload_free(mod);
2186
2187 /* Free any allocated parameters. */
2188 destroy_params(mod->kp, mod->num_kp);
2189
2190 if (is_livepatch_module(mod))
2191 free_module_elf(mod);
2192
2193 /* Now we can delete it from the lists */
2194 mutex_lock(&module_mutex);
2195 /* Unlink carefully: kallsyms could be walking list. */
2196 list_del_rcu(&mod->list);
2197 mod_tree_remove(mod);
2198 /* Remove this module from bug list, this uses list_del_rcu */
2199 module_bug_cleanup(mod);
2200 /* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
2201 synchronize_rcu();
2202 mutex_unlock(&module_mutex);
2203
2204 /* Clean up CFI for the module. */
2205 cfi_cleanup(mod);
2206
2207 /* This may be empty, but that's OK */
2208 module_arch_freeing_init(mod);
2209 trace_android_vh_set_memory_rw((unsigned long)mod->init_layout.base,
2210 (mod->init_layout.size)>>PAGE_SHIFT);
2211 trace_android_vh_set_memory_nx((unsigned long)mod->init_layout.base,
2212 (mod->init_layout.size)>>PAGE_SHIFT);
2213 module_memfree(mod->init_layout.base);
2214 kfree(mod->args);
2215 percpu_modfree(mod);
2216
2217 /* Free lock-classes; relies on the preceding sync_rcu(). */
2218 lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
2219
2220 /* Finally, free the core (containing the module structure) */
2221 trace_android_vh_set_memory_rw((unsigned long)mod->core_layout.base,
2222 (mod->core_layout.size)>>PAGE_SHIFT);
2223 trace_android_vh_set_memory_nx((unsigned long)mod->core_layout.base,
2224 (mod->core_layout.size)>>PAGE_SHIFT);
2225 module_memfree(mod->core_layout.base);
2226 }
2227
__symbol_get(const char * symbol)2228 void *__symbol_get(const char *symbol)
2229 {
2230 struct find_symbol_arg fsa = {
2231 .name = symbol,
2232 .gplok = true,
2233 .warn = true,
2234 };
2235
2236 preempt_disable();
2237 if (!find_symbol(&fsa))
2238 goto fail;
2239 if (fsa.license != GPL_ONLY) {
2240 pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n",
2241 symbol);
2242 goto fail;
2243 }
2244 if (strong_try_module_get(fsa.owner))
2245 goto fail;
2246 preempt_enable();
2247 return (void *)kernel_symbol_value(fsa.sym);
2248 fail:
2249 preempt_enable();
2250 return NULL;
2251 }
2252 EXPORT_SYMBOL_GPL(__symbol_get);
2253
2254 /*
2255 * Ensure that an exported symbol [global namespace] does not already exist
2256 * in the kernel or in some other module's exported symbol table.
2257 *
2258 * You must hold the module_mutex.
2259 */
verify_exported_symbols(struct module * mod)2260 static int verify_exported_symbols(struct module *mod)
2261 {
2262 unsigned int i;
2263 const struct kernel_symbol *s;
2264 struct {
2265 const struct kernel_symbol *sym;
2266 unsigned int num;
2267 } arr[] = {
2268 { mod->syms, mod->num_syms },
2269 { mod->gpl_syms, mod->num_gpl_syms },
2270 };
2271
2272 for (i = 0; i < ARRAY_SIZE(arr); i++) {
2273 for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
2274 struct find_symbol_arg fsa = {
2275 .name = kernel_symbol_name(s),
2276 .gplok = true,
2277 };
2278
2279 if (!mod->sig_ok && gki_is_module_exported_symbol(
2280 kernel_symbol_name(s))) {
2281 pr_err("%s: exporting protected symbol(%s)\n",
2282 mod->name, kernel_symbol_name(s));
2283 return -EACCES;
2284 }
2285
2286 if (find_symbol(&fsa)) {
2287 pr_err("%s: exports duplicate symbol %s"
2288 " (owned by %s)\n",
2289 mod->name, kernel_symbol_name(s),
2290 module_name(fsa.owner));
2291 return -ENOEXEC;
2292 }
2293 }
2294 }
2295 return 0;
2296 }
2297
ignore_undef_symbol(Elf_Half emachine,const char * name)2298 static bool ignore_undef_symbol(Elf_Half emachine, const char *name)
2299 {
2300 /*
2301 * On x86, PIC code and Clang non-PIC code may have call foo@PLT. GNU as
2302 * before 2.37 produces an unreferenced _GLOBAL_OFFSET_TABLE_ on x86-64.
2303 * i386 has a similar problem but may not deserve a fix.
2304 *
2305 * If we ever have to ignore many symbols, consider refactoring the code to
2306 * only warn if referenced by a relocation.
2307 */
2308 if (emachine == EM_386 || emachine == EM_X86_64)
2309 return !strcmp(name, "_GLOBAL_OFFSET_TABLE_");
2310 return false;
2311 }
2312
2313 /* Change all symbols so that st_value encodes the pointer directly. */
simplify_symbols(struct module * mod,const struct load_info * info)2314 static int simplify_symbols(struct module *mod, const struct load_info *info)
2315 {
2316 Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
2317 Elf_Sym *sym = (void *)symsec->sh_addr;
2318 unsigned long secbase;
2319 unsigned int i;
2320 int ret = 0;
2321 const struct kernel_symbol *ksym;
2322
2323 for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
2324 const char *name = info->strtab + sym[i].st_name;
2325
2326 switch (sym[i].st_shndx) {
2327 case SHN_COMMON:
2328 /* Ignore common symbols */
2329 if (!strncmp(name, "__gnu_lto", 9))
2330 break;
2331
2332 /*
2333 * We compiled with -fno-common. These are not
2334 * supposed to happen.
2335 */
2336 pr_debug("Common symbol: %s\n", name);
2337 pr_warn("%s: please compile with -fno-common\n",
2338 mod->name);
2339 ret = -ENOEXEC;
2340 break;
2341
2342 case SHN_ABS:
2343 /* Don't need to do anything */
2344 pr_debug("Absolute symbol: 0x%08lx\n",
2345 (long)sym[i].st_value);
2346 break;
2347
2348 case SHN_LIVEPATCH:
2349 /* Livepatch symbols are resolved by livepatch */
2350 break;
2351
2352 case SHN_UNDEF:
2353 if (!mod->sig_ok &&
2354 gki_is_module_protected_symbol(name)) {
2355 pr_err("%s: is not an Android GKI signed module. It can not access protected symbol: %s\n",
2356 mod->name, name);
2357 return -EACCES;
2358 }
2359
2360 ksym = resolve_symbol_wait(mod, info, name);
2361 /* Ok if resolved. */
2362 if (ksym && !IS_ERR(ksym)) {
2363 sym[i].st_value = kernel_symbol_value(ksym);
2364 break;
2365 }
2366
2367 /* Ok if weak or ignored. */
2368 if (!ksym &&
2369 (ELF_ST_BIND(sym[i].st_info) == STB_WEAK ||
2370 ignore_undef_symbol(info->hdr->e_machine, name)))
2371 break;
2372
2373 ret = PTR_ERR(ksym) ?: -ENOENT;
2374 pr_warn("%s: Unknown symbol %s (err %d)\n",
2375 mod->name, name, ret);
2376 break;
2377
2378 default:
2379 /* Divert to percpu allocation if a percpu var. */
2380 if (sym[i].st_shndx == info->index.pcpu)
2381 secbase = (unsigned long)mod_percpu(mod);
2382 else
2383 secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
2384 sym[i].st_value += secbase;
2385 break;
2386 }
2387 }
2388
2389 return ret;
2390 }
2391
apply_relocations(struct module * mod,const struct load_info * info)2392 static int apply_relocations(struct module *mod, const struct load_info *info)
2393 {
2394 unsigned int i;
2395 int err = 0;
2396
2397 /* Now do relocations. */
2398 for (i = 1; i < info->hdr->e_shnum; i++) {
2399 unsigned int infosec = info->sechdrs[i].sh_info;
2400
2401 /* Not a valid relocation section? */
2402 if (infosec >= info->hdr->e_shnum)
2403 continue;
2404
2405 /* Don't bother with non-allocated sections */
2406 if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
2407 continue;
2408
2409 if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
2410 err = klp_apply_section_relocs(mod, info->sechdrs,
2411 info->secstrings,
2412 info->strtab,
2413 info->index.sym, i,
2414 NULL);
2415 else if (info->sechdrs[i].sh_type == SHT_REL)
2416 err = apply_relocate(info->sechdrs, info->strtab,
2417 info->index.sym, i, mod);
2418 else if (info->sechdrs[i].sh_type == SHT_RELA)
2419 err = apply_relocate_add(info->sechdrs, info->strtab,
2420 info->index.sym, i, mod);
2421 if (err < 0)
2422 break;
2423 }
2424 return err;
2425 }
2426
2427 /* Additional bytes needed by arch in front of individual sections */
arch_mod_section_prepend(struct module * mod,unsigned int section)2428 unsigned int __weak arch_mod_section_prepend(struct module *mod,
2429 unsigned int section)
2430 {
2431 /* default implementation just returns zero */
2432 return 0;
2433 }
2434
2435 /* Update size with this section: return offset. */
get_offset(struct module * mod,unsigned int * size,Elf_Shdr * sechdr,unsigned int section)2436 static long get_offset(struct module *mod, unsigned int *size,
2437 Elf_Shdr *sechdr, unsigned int section)
2438 {
2439 long ret;
2440
2441 *size += arch_mod_section_prepend(mod, section);
2442 ret = ALIGN(*size, sechdr->sh_addralign ?: 1);
2443 *size = ret + sechdr->sh_size;
2444 return ret;
2445 }
2446
module_init_layout_section(const char * sname)2447 bool module_init_layout_section(const char *sname)
2448 {
2449 #ifndef CONFIG_MODULE_UNLOAD
2450 if (module_exit_section(sname))
2451 return true;
2452 #endif
2453 return module_init_section(sname);
2454 }
2455
2456 /*
2457 * Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
2458 * might -- code, read-only data, read-write data, small data. Tally
2459 * sizes, and place the offsets into sh_entsize fields: high bit means it
2460 * belongs in init.
2461 */
layout_sections(struct module * mod,struct load_info * info)2462 static void layout_sections(struct module *mod, struct load_info *info)
2463 {
2464 static unsigned long const masks[][2] = {
2465 /*
2466 * NOTE: all executable code must be the first section
2467 * in this array; otherwise modify the text_size
2468 * finder in the two loops below
2469 */
2470 { SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
2471 { SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
2472 { SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
2473 { SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
2474 { ARCH_SHF_SMALL | SHF_ALLOC, 0 }
2475 };
2476 unsigned int m, i;
2477
2478 for (i = 0; i < info->hdr->e_shnum; i++)
2479 info->sechdrs[i].sh_entsize = ~0UL;
2480
2481 pr_debug("Core section allocation order:\n");
2482 for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2483 for (i = 0; i < info->hdr->e_shnum; ++i) {
2484 Elf_Shdr *s = &info->sechdrs[i];
2485 const char *sname = info->secstrings + s->sh_name;
2486
2487 if ((s->sh_flags & masks[m][0]) != masks[m][0]
2488 || (s->sh_flags & masks[m][1])
2489 || s->sh_entsize != ~0UL
2490 || module_init_layout_section(sname))
2491 continue;
2492 s->sh_entsize = get_offset(mod, &mod->core_layout.size, s, i);
2493 pr_debug("\t%s\n", sname);
2494 }
2495 switch (m) {
2496 case 0: /* executable */
2497 mod->core_layout.size = debug_align(mod->core_layout.size);
2498 mod->core_layout.text_size = mod->core_layout.size;
2499 break;
2500 case 1: /* RO: text and ro-data */
2501 mod->core_layout.size = debug_align(mod->core_layout.size);
2502 mod->core_layout.ro_size = mod->core_layout.size;
2503 break;
2504 case 2: /* RO after init */
2505 mod->core_layout.size = debug_align(mod->core_layout.size);
2506 mod->core_layout.ro_after_init_size = mod->core_layout.size;
2507 break;
2508 case 4: /* whole core */
2509 mod->core_layout.size = debug_align(mod->core_layout.size);
2510 break;
2511 }
2512 }
2513
2514 pr_debug("Init section allocation order:\n");
2515 for (m = 0; m < ARRAY_SIZE(masks); ++m) {
2516 for (i = 0; i < info->hdr->e_shnum; ++i) {
2517 Elf_Shdr *s = &info->sechdrs[i];
2518 const char *sname = info->secstrings + s->sh_name;
2519
2520 if ((s->sh_flags & masks[m][0]) != masks[m][0]
2521 || (s->sh_flags & masks[m][1])
2522 || s->sh_entsize != ~0UL
2523 || !module_init_layout_section(sname))
2524 continue;
2525 s->sh_entsize = (get_offset(mod, &mod->init_layout.size, s, i)
2526 | INIT_OFFSET_MASK);
2527 pr_debug("\t%s\n", sname);
2528 }
2529 switch (m) {
2530 case 0: /* executable */
2531 mod->init_layout.size = debug_align(mod->init_layout.size);
2532 mod->init_layout.text_size = mod->init_layout.size;
2533 break;
2534 case 1: /* RO: text and ro-data */
2535 mod->init_layout.size = debug_align(mod->init_layout.size);
2536 mod->init_layout.ro_size = mod->init_layout.size;
2537 break;
2538 case 2:
2539 /*
2540 * RO after init doesn't apply to init_layout (only
2541 * core_layout), so it just takes the value of ro_size.
2542 */
2543 mod->init_layout.ro_after_init_size = mod->init_layout.ro_size;
2544 break;
2545 case 4: /* whole init */
2546 mod->init_layout.size = debug_align(mod->init_layout.size);
2547 break;
2548 }
2549 }
2550 }
2551
set_license(struct module * mod,const char * license)2552 static void set_license(struct module *mod, const char *license)
2553 {
2554 if (!license)
2555 license = "unspecified";
2556
2557 if (!license_is_gpl_compatible(license)) {
2558 if (!test_taint(TAINT_PROPRIETARY_MODULE))
2559 pr_warn("%s: module license '%s' taints kernel.\n",
2560 mod->name, license);
2561 add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2562 LOCKDEP_NOW_UNRELIABLE);
2563 }
2564 }
2565
2566 /* Parse tag=value strings from .modinfo section */
next_string(char * string,unsigned long * secsize)2567 static char *next_string(char *string, unsigned long *secsize)
2568 {
2569 /* Skip non-zero chars */
2570 while (string[0]) {
2571 string++;
2572 if ((*secsize)-- <= 1)
2573 return NULL;
2574 }
2575
2576 /* Skip any zero padding. */
2577 while (!string[0]) {
2578 string++;
2579 if ((*secsize)-- <= 1)
2580 return NULL;
2581 }
2582 return string;
2583 }
2584
get_next_modinfo(const struct load_info * info,const char * tag,char * prev)2585 static char *get_next_modinfo(const struct load_info *info, const char *tag,
2586 char *prev)
2587 {
2588 char *p;
2589 unsigned int taglen = strlen(tag);
2590 Elf_Shdr *infosec = &info->sechdrs[info->index.info];
2591 unsigned long size = infosec->sh_size;
2592
2593 /*
2594 * get_modinfo() calls made before rewrite_section_headers()
2595 * must use sh_offset, as sh_addr isn't set!
2596 */
2597 char *modinfo = (char *)info->hdr + infosec->sh_offset;
2598
2599 if (prev) {
2600 size -= prev - modinfo;
2601 modinfo = next_string(prev, &size);
2602 }
2603
2604 for (p = modinfo; p; p = next_string(p, &size)) {
2605 if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
2606 return p + taglen + 1;
2607 }
2608 return NULL;
2609 }
2610
get_modinfo(const struct load_info * info,const char * tag)2611 static char *get_modinfo(const struct load_info *info, const char *tag)
2612 {
2613 return get_next_modinfo(info, tag, NULL);
2614 }
2615
setup_modinfo(struct module * mod,struct load_info * info)2616 static void setup_modinfo(struct module *mod, struct load_info *info)
2617 {
2618 struct module_attribute *attr;
2619 int i;
2620
2621 for (i = 0; (attr = modinfo_attrs[i]); i++) {
2622 if (attr->setup)
2623 attr->setup(mod, get_modinfo(info, attr->attr.name));
2624 }
2625 }
2626
free_modinfo(struct module * mod)2627 static void free_modinfo(struct module *mod)
2628 {
2629 struct module_attribute *attr;
2630 int i;
2631
2632 for (i = 0; (attr = modinfo_attrs[i]); i++) {
2633 if (attr->free)
2634 attr->free(mod);
2635 }
2636 }
2637
2638 #ifdef CONFIG_KALLSYMS
2639
2640 /* 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)2641 static const struct kernel_symbol *lookup_exported_symbol(const char *name,
2642 const struct kernel_symbol *start,
2643 const struct kernel_symbol *stop)
2644 {
2645 return bsearch(name, start, stop - start,
2646 sizeof(struct kernel_symbol), cmp_name);
2647 }
2648
is_exported(const char * name,unsigned long value,const struct module * mod)2649 static int is_exported(const char *name, unsigned long value,
2650 const struct module *mod)
2651 {
2652 const struct kernel_symbol *ks;
2653 if (!mod)
2654 ks = lookup_exported_symbol(name, __start___ksymtab, __stop___ksymtab);
2655 else
2656 ks = lookup_exported_symbol(name, mod->syms, mod->syms + mod->num_syms);
2657
2658 return ks != NULL && kernel_symbol_value(ks) == value;
2659 }
2660
2661 /* As per nm */
elf_type(const Elf_Sym * sym,const struct load_info * info)2662 static char elf_type(const Elf_Sym *sym, const struct load_info *info)
2663 {
2664 const Elf_Shdr *sechdrs = info->sechdrs;
2665
2666 if (ELF_ST_BIND(sym->st_info) == STB_WEAK) {
2667 if (ELF_ST_TYPE(sym->st_info) == STT_OBJECT)
2668 return 'v';
2669 else
2670 return 'w';
2671 }
2672 if (sym->st_shndx == SHN_UNDEF)
2673 return 'U';
2674 if (sym->st_shndx == SHN_ABS || sym->st_shndx == info->index.pcpu)
2675 return 'a';
2676 if (sym->st_shndx >= SHN_LORESERVE)
2677 return '?';
2678 if (sechdrs[sym->st_shndx].sh_flags & SHF_EXECINSTR)
2679 return 't';
2680 if (sechdrs[sym->st_shndx].sh_flags & SHF_ALLOC
2681 && sechdrs[sym->st_shndx].sh_type != SHT_NOBITS) {
2682 if (!(sechdrs[sym->st_shndx].sh_flags & SHF_WRITE))
2683 return 'r';
2684 else if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2685 return 'g';
2686 else
2687 return 'd';
2688 }
2689 if (sechdrs[sym->st_shndx].sh_type == SHT_NOBITS) {
2690 if (sechdrs[sym->st_shndx].sh_flags & ARCH_SHF_SMALL)
2691 return 's';
2692 else
2693 return 'b';
2694 }
2695 if (strstarts(info->secstrings + sechdrs[sym->st_shndx].sh_name,
2696 ".debug")) {
2697 return 'n';
2698 }
2699 return '?';
2700 }
2701
is_core_symbol(const Elf_Sym * src,const Elf_Shdr * sechdrs,unsigned int shnum,unsigned int pcpundx)2702 static bool is_core_symbol(const Elf_Sym *src, const Elf_Shdr *sechdrs,
2703 unsigned int shnum, unsigned int pcpundx)
2704 {
2705 const Elf_Shdr *sec;
2706
2707 if (src->st_shndx == SHN_UNDEF
2708 || src->st_shndx >= shnum
2709 || !src->st_name)
2710 return false;
2711
2712 #ifdef CONFIG_KALLSYMS_ALL
2713 if (src->st_shndx == pcpundx)
2714 return true;
2715 #endif
2716
2717 sec = sechdrs + src->st_shndx;
2718 if (!(sec->sh_flags & SHF_ALLOC)
2719 #ifndef CONFIG_KALLSYMS_ALL
2720 || !(sec->sh_flags & SHF_EXECINSTR)
2721 #endif
2722 || (sec->sh_entsize & INIT_OFFSET_MASK))
2723 return false;
2724
2725 return true;
2726 }
2727
2728 /*
2729 * We only allocate and copy the strings needed by the parts of symtab
2730 * we keep. This is simple, but has the effect of making multiple
2731 * copies of duplicates. We could be more sophisticated, see
2732 * linux-kernel thread starting with
2733 * <73defb5e4bca04a6431392cc341112b1@localhost>.
2734 */
layout_symtab(struct module * mod,struct load_info * info)2735 static void layout_symtab(struct module *mod, struct load_info *info)
2736 {
2737 Elf_Shdr *symsect = info->sechdrs + info->index.sym;
2738 Elf_Shdr *strsect = info->sechdrs + info->index.str;
2739 const Elf_Sym *src;
2740 unsigned int i, nsrc, ndst, strtab_size = 0;
2741
2742 /* Put symbol section at end of init part of module. */
2743 symsect->sh_flags |= SHF_ALLOC;
2744 symsect->sh_entsize = get_offset(mod, &mod->init_layout.size, symsect,
2745 info->index.sym) | INIT_OFFSET_MASK;
2746 pr_debug("\t%s\n", info->secstrings + symsect->sh_name);
2747
2748 src = (void *)info->hdr + symsect->sh_offset;
2749 nsrc = symsect->sh_size / sizeof(*src);
2750
2751 /* Compute total space required for the core symbols' strtab. */
2752 for (ndst = i = 0; i < nsrc; i++) {
2753 if (i == 0 || is_livepatch_module(mod) ||
2754 is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
2755 info->index.pcpu)) {
2756 strtab_size += strlen(&info->strtab[src[i].st_name])+1;
2757 ndst++;
2758 }
2759 }
2760
2761 /* Append room for core symbols at end of core part. */
2762 info->symoffs = ALIGN(mod->core_layout.size, symsect->sh_addralign ?: 1);
2763 info->stroffs = mod->core_layout.size = info->symoffs + ndst * sizeof(Elf_Sym);
2764 mod->core_layout.size += strtab_size;
2765 info->core_typeoffs = mod->core_layout.size;
2766 mod->core_layout.size += ndst * sizeof(char);
2767 mod->core_layout.size = debug_align(mod->core_layout.size);
2768
2769 /* Put string table section at end of init part of module. */
2770 strsect->sh_flags |= SHF_ALLOC;
2771 strsect->sh_entsize = get_offset(mod, &mod->init_layout.size, strsect,
2772 info->index.str) | INIT_OFFSET_MASK;
2773 pr_debug("\t%s\n", info->secstrings + strsect->sh_name);
2774
2775 /* We'll tack temporary mod_kallsyms on the end. */
2776 mod->init_layout.size = ALIGN(mod->init_layout.size,
2777 __alignof__(struct mod_kallsyms));
2778 info->mod_kallsyms_init_off = mod->init_layout.size;
2779 mod->init_layout.size += sizeof(struct mod_kallsyms);
2780 info->init_typeoffs = mod->init_layout.size;
2781 mod->init_layout.size += nsrc * sizeof(char);
2782 mod->init_layout.size = debug_align(mod->init_layout.size);
2783 }
2784
2785 /*
2786 * We use the full symtab and strtab which layout_symtab arranged to
2787 * be appended to the init section. Later we switch to the cut-down
2788 * core-only ones.
2789 */
add_kallsyms(struct module * mod,const struct load_info * info)2790 static void add_kallsyms(struct module *mod, const struct load_info *info)
2791 {
2792 unsigned int i, ndst;
2793 const Elf_Sym *src;
2794 Elf_Sym *dst;
2795 char *s;
2796 Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
2797
2798 /* Set up to point into init section. */
2799 mod->kallsyms = mod->init_layout.base + info->mod_kallsyms_init_off;
2800
2801 mod->kallsyms->symtab = (void *)symsec->sh_addr;
2802 mod->kallsyms->num_symtab = symsec->sh_size / sizeof(Elf_Sym);
2803 /* Make sure we get permanent strtab: don't use info->strtab. */
2804 mod->kallsyms->strtab = (void *)info->sechdrs[info->index.str].sh_addr;
2805 mod->kallsyms->typetab = mod->init_layout.base + info->init_typeoffs;
2806
2807 /*
2808 * Now populate the cut down core kallsyms for after init
2809 * and set types up while we still have access to sections.
2810 */
2811 mod->core_kallsyms.symtab = dst = mod->core_layout.base + info->symoffs;
2812 mod->core_kallsyms.strtab = s = mod->core_layout.base + info->stroffs;
2813 mod->core_kallsyms.typetab = mod->core_layout.base + info->core_typeoffs;
2814 src = mod->kallsyms->symtab;
2815 for (ndst = i = 0; i < mod->kallsyms->num_symtab; i++) {
2816 mod->kallsyms->typetab[i] = elf_type(src + i, info);
2817 if (i == 0 || is_livepatch_module(mod) ||
2818 is_core_symbol(src+i, info->sechdrs, info->hdr->e_shnum,
2819 info->index.pcpu)) {
2820 mod->core_kallsyms.typetab[ndst] =
2821 mod->kallsyms->typetab[i];
2822 dst[ndst] = src[i];
2823 dst[ndst++].st_name = s - mod->core_kallsyms.strtab;
2824 s += strlcpy(s, &mod->kallsyms->strtab[src[i].st_name],
2825 KSYM_NAME_LEN) + 1;
2826 }
2827 }
2828 mod->core_kallsyms.num_symtab = ndst;
2829 }
2830 #else
layout_symtab(struct module * mod,struct load_info * info)2831 static inline void layout_symtab(struct module *mod, struct load_info *info)
2832 {
2833 }
2834
add_kallsyms(struct module * mod,const struct load_info * info)2835 static void add_kallsyms(struct module *mod, const struct load_info *info)
2836 {
2837 }
2838 #endif /* CONFIG_KALLSYMS */
2839
2840 #if IS_ENABLED(CONFIG_KALLSYMS) && IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
init_build_id(struct module * mod,const struct load_info * info)2841 static void init_build_id(struct module *mod, const struct load_info *info)
2842 {
2843 const Elf_Shdr *sechdr;
2844 unsigned int i;
2845
2846 for (i = 0; i < info->hdr->e_shnum; i++) {
2847 sechdr = &info->sechdrs[i];
2848 if (!sect_empty(sechdr) && sechdr->sh_type == SHT_NOTE &&
2849 !build_id_parse_buf((void *)sechdr->sh_addr, mod->build_id,
2850 sechdr->sh_size))
2851 break;
2852 }
2853 }
2854 #else
init_build_id(struct module * mod,const struct load_info * info)2855 static void init_build_id(struct module *mod, const struct load_info *info)
2856 {
2857 }
2858 #endif
2859
dynamic_debug_setup(struct module * mod,struct _ddebug * debug,unsigned int num)2860 static void dynamic_debug_setup(struct module *mod, struct _ddebug *debug, unsigned int num)
2861 {
2862 if (!debug)
2863 return;
2864 ddebug_add_module(debug, num, mod->name);
2865 }
2866
dynamic_debug_remove(struct module * mod,struct _ddebug * debug)2867 static void dynamic_debug_remove(struct module *mod, struct _ddebug *debug)
2868 {
2869 if (debug)
2870 ddebug_remove_module(mod->name);
2871 }
2872
module_alloc(unsigned long size)2873 void * __weak module_alloc(unsigned long size)
2874 {
2875 return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
2876 GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
2877 NUMA_NO_NODE, __builtin_return_address(0));
2878 }
2879
module_init_section(const char * name)2880 bool __weak module_init_section(const char *name)
2881 {
2882 return strstarts(name, ".init");
2883 }
2884
module_exit_section(const char * name)2885 bool __weak module_exit_section(const char *name)
2886 {
2887 return strstarts(name, ".exit");
2888 }
2889
2890 #ifdef CONFIG_DEBUG_KMEMLEAK
kmemleak_load_module(const struct module * mod,const struct load_info * info)2891 static void kmemleak_load_module(const struct module *mod,
2892 const struct load_info *info)
2893 {
2894 unsigned int i;
2895
2896 /* only scan the sections containing data */
2897 kmemleak_scan_area(mod, sizeof(struct module), GFP_KERNEL);
2898
2899 for (i = 1; i < info->hdr->e_shnum; i++) {
2900 /* Scan all writable sections that's not executable */
2901 if (!(info->sechdrs[i].sh_flags & SHF_ALLOC) ||
2902 !(info->sechdrs[i].sh_flags & SHF_WRITE) ||
2903 (info->sechdrs[i].sh_flags & SHF_EXECINSTR))
2904 continue;
2905
2906 kmemleak_scan_area((void *)info->sechdrs[i].sh_addr,
2907 info->sechdrs[i].sh_size, GFP_KERNEL);
2908 }
2909 }
2910 #else
kmemleak_load_module(const struct module * mod,const struct load_info * info)2911 static inline void kmemleak_load_module(const struct module *mod,
2912 const struct load_info *info)
2913 {
2914 }
2915 #endif
2916
2917 #ifdef CONFIG_MODULE_SIG
module_sig_check(struct load_info * info,int flags)2918 static int module_sig_check(struct load_info *info, int flags)
2919 {
2920 int err = -ENODATA;
2921 const unsigned long markerlen = sizeof(MODULE_SIG_STRING) - 1;
2922 const char *reason;
2923 const void *mod = info->hdr;
2924
2925 /*
2926 * Require flags == 0, as a module with version information
2927 * removed is no longer the module that was signed
2928 */
2929 if (flags == 0 &&
2930 info->len > markerlen &&
2931 memcmp(mod + info->len - markerlen, MODULE_SIG_STRING, markerlen) == 0) {
2932 /* We truncate the module to discard the signature */
2933 info->len -= markerlen;
2934 err = mod_verify_sig(mod, info);
2935 if (!err) {
2936 info->sig_ok = true;
2937 return 0;
2938 }
2939 }
2940
2941 /*
2942 * We don't permit modules to be loaded into the trusted kernels
2943 * without a valid signature on them, but if we're not enforcing,
2944 * certain errors are non-fatal.
2945 */
2946 switch (err) {
2947 case -ENODATA:
2948 reason = "unsigned module";
2949 break;
2950 case -ENOPKG:
2951 reason = "module with unsupported crypto";
2952 break;
2953 case -ENOKEY:
2954 reason = "module with unavailable key";
2955 break;
2956
2957 default:
2958 /*
2959 * All other errors are fatal, including lack of memory,
2960 * unparseable signatures, and signature check failures --
2961 * even if signatures aren't required.
2962 */
2963 return err;
2964 }
2965
2966 if (is_module_sig_enforced()) {
2967 pr_notice("Loading of %s is rejected\n", reason);
2968 return -EKEYREJECTED;
2969 }
2970
2971 /*
2972 * ANDROID: GKI: Do not prevent loading of unsigned modules;
2973 * as all modules except GKI modules are not signed.
2974 */
2975 #ifndef CONFIG_MODULE_SIG_PROTECT
2976 return security_locked_down(LOCKDOWN_MODULE_SIGNATURE);
2977 #else
2978 return 0;
2979 #endif
2980 }
2981 #else /* !CONFIG_MODULE_SIG */
module_sig_check(struct load_info * info,int flags)2982 static int module_sig_check(struct load_info *info, int flags)
2983 {
2984 return 0;
2985 }
2986 #endif /* !CONFIG_MODULE_SIG */
2987
validate_section_offset(struct load_info * info,Elf_Shdr * shdr)2988 static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
2989 {
2990 unsigned long secend;
2991
2992 /*
2993 * Check for both overflow and offset/size being
2994 * too large.
2995 */
2996 secend = shdr->sh_offset + shdr->sh_size;
2997 if (secend < shdr->sh_offset || secend > info->len)
2998 return -ENOEXEC;
2999
3000 return 0;
3001 }
3002
3003 /*
3004 * Sanity checks against invalid binaries, wrong arch, weird elf version.
3005 *
3006 * Also do basic validity checks against section offsets and sizes, the
3007 * section name string table, and the indices used for it (sh_name).
3008 */
elf_validity_check(struct load_info * info)3009 static int elf_validity_check(struct load_info *info)
3010 {
3011 unsigned int i;
3012 Elf_Shdr *shdr, *strhdr;
3013 int err;
3014
3015 if (info->len < sizeof(*(info->hdr))) {
3016 pr_err("Invalid ELF header len %lu\n", info->len);
3017 goto no_exec;
3018 }
3019
3020 if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0) {
3021 pr_err("Invalid ELF header magic: != %s\n", ELFMAG);
3022 goto no_exec;
3023 }
3024 if (info->hdr->e_type != ET_REL) {
3025 pr_err("Invalid ELF header type: %u != %u\n",
3026 info->hdr->e_type, ET_REL);
3027 goto no_exec;
3028 }
3029 if (!elf_check_arch(info->hdr)) {
3030 pr_err("Invalid architecture in ELF header: %u\n",
3031 info->hdr->e_machine);
3032 goto no_exec;
3033 }
3034 if (info->hdr->e_shentsize != sizeof(Elf_Shdr)) {
3035 pr_err("Invalid ELF section header size\n");
3036 goto no_exec;
3037 }
3038
3039 /*
3040 * e_shnum is 16 bits, and sizeof(Elf_Shdr) is
3041 * known and small. So e_shnum * sizeof(Elf_Shdr)
3042 * will not overflow unsigned long on any platform.
3043 */
3044 if (info->hdr->e_shoff >= info->len
3045 || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
3046 info->len - info->hdr->e_shoff)) {
3047 pr_err("Invalid ELF section header overflow\n");
3048 goto no_exec;
3049 }
3050
3051 info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
3052
3053 /*
3054 * Verify if the section name table index is valid.
3055 */
3056 if (info->hdr->e_shstrndx == SHN_UNDEF
3057 || info->hdr->e_shstrndx >= info->hdr->e_shnum) {
3058 pr_err("Invalid ELF section name index: %d || e_shstrndx (%d) >= e_shnum (%d)\n",
3059 info->hdr->e_shstrndx, info->hdr->e_shstrndx,
3060 info->hdr->e_shnum);
3061 goto no_exec;
3062 }
3063
3064 strhdr = &info->sechdrs[info->hdr->e_shstrndx];
3065 err = validate_section_offset(info, strhdr);
3066 if (err < 0) {
3067 pr_err("Invalid ELF section hdr(type %u)\n", strhdr->sh_type);
3068 return err;
3069 }
3070
3071 /*
3072 * The section name table must be NUL-terminated, as required
3073 * by the spec. This makes strcmp and pr_* calls that access
3074 * strings in the section safe.
3075 */
3076 info->secstrings = (void *)info->hdr + strhdr->sh_offset;
3077 if (strhdr->sh_size == 0) {
3078 pr_err("empty section name table\n");
3079 goto no_exec;
3080 }
3081 if (info->secstrings[strhdr->sh_size - 1] != '\0') {
3082 pr_err("ELF Spec violation: section name table isn't null terminated\n");
3083 goto no_exec;
3084 }
3085
3086 /*
3087 * The code assumes that section 0 has a length of zero and
3088 * an addr of zero, so check for it.
3089 */
3090 if (info->sechdrs[0].sh_type != SHT_NULL
3091 || info->sechdrs[0].sh_size != 0
3092 || info->sechdrs[0].sh_addr != 0) {
3093 pr_err("ELF Spec violation: section 0 type(%d)!=SH_NULL or non-zero len or addr\n",
3094 info->sechdrs[0].sh_type);
3095 goto no_exec;
3096 }
3097
3098 for (i = 1; i < info->hdr->e_shnum; i++) {
3099 shdr = &info->sechdrs[i];
3100 switch (shdr->sh_type) {
3101 case SHT_NULL:
3102 case SHT_NOBITS:
3103 continue;
3104 case SHT_SYMTAB:
3105 if (shdr->sh_link == SHN_UNDEF
3106 || shdr->sh_link >= info->hdr->e_shnum) {
3107 pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n",
3108 shdr->sh_link, shdr->sh_link,
3109 info->hdr->e_shnum);
3110 goto no_exec;
3111 }
3112 fallthrough;
3113 default:
3114 err = validate_section_offset(info, shdr);
3115 if (err < 0) {
3116 pr_err("Invalid ELF section in module (section %u type %u)\n",
3117 i, shdr->sh_type);
3118 return err;
3119 }
3120
3121 if (shdr->sh_flags & SHF_ALLOC) {
3122 if (shdr->sh_name >= strhdr->sh_size) {
3123 pr_err("Invalid ELF section name in module (section %u type %u)\n",
3124 i, shdr->sh_type);
3125 return -ENOEXEC;
3126 }
3127 }
3128 break;
3129 }
3130 }
3131
3132 return 0;
3133
3134 no_exec:
3135 return -ENOEXEC;
3136 }
3137
3138 #define COPY_CHUNK_SIZE (16*PAGE_SIZE)
3139
copy_chunked_from_user(void * dst,const void __user * usrc,unsigned long len)3140 static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned long len)
3141 {
3142 do {
3143 unsigned long n = min(len, COPY_CHUNK_SIZE);
3144
3145 if (copy_from_user(dst, usrc, n) != 0)
3146 return -EFAULT;
3147 cond_resched();
3148 dst += n;
3149 usrc += n;
3150 len -= n;
3151 } while (len);
3152 return 0;
3153 }
3154
3155 #ifdef CONFIG_LIVEPATCH
check_modinfo_livepatch(struct module * mod,struct load_info * info)3156 static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
3157 {
3158 if (get_modinfo(info, "livepatch")) {
3159 mod->klp = true;
3160 add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
3161 pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
3162 mod->name);
3163 }
3164
3165 return 0;
3166 }
3167 #else /* !CONFIG_LIVEPATCH */
check_modinfo_livepatch(struct module * mod,struct load_info * info)3168 static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
3169 {
3170 if (get_modinfo(info, "livepatch")) {
3171 pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
3172 mod->name);
3173 return -ENOEXEC;
3174 }
3175
3176 return 0;
3177 }
3178 #endif /* CONFIG_LIVEPATCH */
3179
check_modinfo_retpoline(struct module * mod,struct load_info * info)3180 static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
3181 {
3182 if (retpoline_module_ok(get_modinfo(info, "retpoline")))
3183 return;
3184
3185 pr_warn("%s: loading module not compiled with retpoline compiler.\n",
3186 mod->name);
3187 }
3188
3189 /* Sets info->hdr and info->len. */
copy_module_from_user(const void __user * umod,unsigned long len,struct load_info * info)3190 static int copy_module_from_user(const void __user *umod, unsigned long len,
3191 struct load_info *info)
3192 {
3193 int err;
3194
3195 info->len = len;
3196 if (info->len < sizeof(*(info->hdr)))
3197 return -ENOEXEC;
3198
3199 err = security_kernel_load_data(LOADING_MODULE, true);
3200 if (err)
3201 return err;
3202
3203 /* Suck in entire file: we'll want most of it. */
3204 info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN);
3205 if (!info->hdr)
3206 return -ENOMEM;
3207
3208 if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) {
3209 err = -EFAULT;
3210 goto out;
3211 }
3212
3213 err = security_kernel_post_load_data((char *)info->hdr, info->len,
3214 LOADING_MODULE, "init_module");
3215 out:
3216 if (err)
3217 vfree(info->hdr);
3218
3219 return err;
3220 }
3221
free_copy(struct load_info * info)3222 static void free_copy(struct load_info *info)
3223 {
3224 vfree(info->hdr);
3225 }
3226
rewrite_section_headers(struct load_info * info,int flags)3227 static int rewrite_section_headers(struct load_info *info, int flags)
3228 {
3229 unsigned int i;
3230
3231 /* This should always be true, but let's be sure. */
3232 info->sechdrs[0].sh_addr = 0;
3233
3234 for (i = 1; i < info->hdr->e_shnum; i++) {
3235 Elf_Shdr *shdr = &info->sechdrs[i];
3236
3237 /*
3238 * Mark all sections sh_addr with their address in the
3239 * temporary image.
3240 */
3241 shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
3242
3243 }
3244
3245 /* Track but don't keep modinfo and version sections. */
3246 info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
3247 info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
3248
3249 return 0;
3250 }
3251
3252 /*
3253 * Set up our basic convenience variables (pointers to section headers,
3254 * search for module section index etc), and do some basic section
3255 * verification.
3256 *
3257 * Set info->mod to the temporary copy of the module in info->hdr. The final one
3258 * will be allocated in move_module().
3259 */
setup_load_info(struct load_info * info,int flags)3260 static int setup_load_info(struct load_info *info, int flags)
3261 {
3262 unsigned int i;
3263
3264 /* Try to find a name early so we can log errors with a module name */
3265 info->index.info = find_sec(info, ".modinfo");
3266 if (info->index.info)
3267 info->name = get_modinfo(info, "name");
3268
3269 /* Find internal symbols and strings. */
3270 for (i = 1; i < info->hdr->e_shnum; i++) {
3271 if (info->sechdrs[i].sh_type == SHT_SYMTAB) {
3272 info->index.sym = i;
3273 info->index.str = info->sechdrs[i].sh_link;
3274 info->strtab = (char *)info->hdr
3275 + info->sechdrs[info->index.str].sh_offset;
3276 break;
3277 }
3278 }
3279
3280 if (info->index.sym == 0) {
3281 pr_warn("%s: module has no symbols (stripped?)\n",
3282 info->name ?: "(missing .modinfo section or name field)");
3283 return -ENOEXEC;
3284 }
3285
3286 info->index.mod = find_sec(info, ".gnu.linkonce.this_module");
3287 if (!info->index.mod) {
3288 pr_warn("%s: No module found in object\n",
3289 info->name ?: "(missing .modinfo section or name field)");
3290 return -ENOEXEC;
3291 }
3292 /* This is temporary: point mod into copy of data. */
3293 info->mod = (void *)info->hdr + info->sechdrs[info->index.mod].sh_offset;
3294
3295 /*
3296 * If we didn't load the .modinfo 'name' field earlier, fall back to
3297 * on-disk struct mod 'name' field.
3298 */
3299 if (!info->name)
3300 info->name = info->mod->name;
3301
3302 if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
3303 info->index.vers = 0; /* Pretend no __versions section! */
3304 else
3305 info->index.vers = find_sec(info, "__versions");
3306
3307 info->index.pcpu = find_pcpusec(info);
3308
3309 return 0;
3310 }
3311
check_modinfo(struct module * mod,struct load_info * info,int flags)3312 static int check_modinfo(struct module *mod, struct load_info *info, int flags)
3313 {
3314 const char *modmagic = get_modinfo(info, "vermagic");
3315 int err;
3316
3317 if (flags & MODULE_INIT_IGNORE_VERMAGIC)
3318 modmagic = NULL;
3319
3320 /* This is allowed: modprobe --force will invalidate it. */
3321 if (!modmagic) {
3322 err = try_to_force_load(mod, "bad vermagic");
3323 if (err)
3324 return err;
3325 } else if (!same_magic(modmagic, vermagic, info->index.vers)) {
3326 pr_err("%s: version magic '%s' should be '%s'\n",
3327 info->name, modmagic, vermagic);
3328 return -ENOEXEC;
3329 }
3330
3331 if (!get_modinfo(info, "intree")) {
3332 if (!test_taint(TAINT_OOT_MODULE))
3333 pr_warn("%s: loading out-of-tree module taints kernel.\n",
3334 mod->name);
3335 add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
3336 }
3337
3338 check_modinfo_retpoline(mod, info);
3339
3340 if (get_modinfo(info, "staging")) {
3341 add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
3342 pr_warn("%s: module is from the staging directory, the quality "
3343 "is unknown, you have been warned.\n", mod->name);
3344 }
3345
3346 err = check_modinfo_livepatch(mod, info);
3347 if (err)
3348 return err;
3349
3350 /* Set up license info based on the info section */
3351 set_license(mod, get_modinfo(info, "license"));
3352
3353 return 0;
3354 }
3355
find_module_sections(struct module * mod,struct load_info * info)3356 static int find_module_sections(struct module *mod, struct load_info *info)
3357 {
3358 mod->kp = section_objs(info, "__param",
3359 sizeof(*mod->kp), &mod->num_kp);
3360 mod->syms = section_objs(info, "__ksymtab",
3361 sizeof(*mod->syms), &mod->num_syms);
3362 mod->crcs = section_addr(info, "__kcrctab");
3363 mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
3364 sizeof(*mod->gpl_syms),
3365 &mod->num_gpl_syms);
3366 mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
3367
3368 #ifdef CONFIG_CONSTRUCTORS
3369 mod->ctors = section_objs(info, ".ctors",
3370 sizeof(*mod->ctors), &mod->num_ctors);
3371 if (!mod->ctors)
3372 mod->ctors = section_objs(info, ".init_array",
3373 sizeof(*mod->ctors), &mod->num_ctors);
3374 else if (find_sec(info, ".init_array")) {
3375 /*
3376 * This shouldn't happen with same compiler and binutils
3377 * building all parts of the module.
3378 */
3379 pr_warn("%s: has both .ctors and .init_array.\n",
3380 mod->name);
3381 return -EINVAL;
3382 }
3383 #endif
3384
3385 mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
3386 &mod->noinstr_text_size);
3387
3388 #ifdef CONFIG_TRACEPOINTS
3389 mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
3390 sizeof(*mod->tracepoints_ptrs),
3391 &mod->num_tracepoints);
3392 #endif
3393 #ifdef CONFIG_TREE_SRCU
3394 mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs",
3395 sizeof(*mod->srcu_struct_ptrs),
3396 &mod->num_srcu_structs);
3397 #endif
3398 #ifdef CONFIG_BPF_EVENTS
3399 mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map",
3400 sizeof(*mod->bpf_raw_events),
3401 &mod->num_bpf_raw_events);
3402 #endif
3403 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
3404 mod->btf_data = any_section_objs(info, ".BTF", 1, &mod->btf_data_size);
3405 #endif
3406 #ifdef CONFIG_JUMP_LABEL
3407 mod->jump_entries = section_objs(info, "__jump_table",
3408 sizeof(*mod->jump_entries),
3409 &mod->num_jump_entries);
3410 #endif
3411 #ifdef CONFIG_EVENT_TRACING
3412 mod->trace_events = section_objs(info, "_ftrace_events",
3413 sizeof(*mod->trace_events),
3414 &mod->num_trace_events);
3415 mod->trace_evals = section_objs(info, "_ftrace_eval_map",
3416 sizeof(*mod->trace_evals),
3417 &mod->num_trace_evals);
3418 #endif
3419 #ifdef CONFIG_TRACING
3420 mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
3421 sizeof(*mod->trace_bprintk_fmt_start),
3422 &mod->num_trace_bprintk_fmt);
3423 #endif
3424 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
3425 /* sechdrs[0].sh_size is always zero */
3426 mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
3427 sizeof(*mod->ftrace_callsites),
3428 &mod->num_ftrace_callsites);
3429 #endif
3430 #ifdef CONFIG_FUNCTION_ERROR_INJECTION
3431 mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
3432 sizeof(*mod->ei_funcs),
3433 &mod->num_ei_funcs);
3434 #endif
3435 #ifdef CONFIG_KPROBES
3436 mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
3437 &mod->kprobes_text_size);
3438 mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
3439 sizeof(unsigned long),
3440 &mod->num_kprobe_blacklist);
3441 #endif
3442 #ifdef CONFIG_PRINTK_INDEX
3443 mod->printk_index_start = section_objs(info, ".printk_index",
3444 sizeof(*mod->printk_index_start),
3445 &mod->printk_index_size);
3446 #endif
3447 #ifdef CONFIG_HAVE_STATIC_CALL_INLINE
3448 mod->static_call_sites = section_objs(info, ".static_call_sites",
3449 sizeof(*mod->static_call_sites),
3450 &mod->num_static_call_sites);
3451 #endif
3452 mod->extable = section_objs(info, "__ex_table",
3453 sizeof(*mod->extable), &mod->num_exentries);
3454
3455 if (section_addr(info, "__obsparm"))
3456 pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
3457
3458 info->debug = section_objs(info, "__dyndbg",
3459 sizeof(*info->debug), &info->num_debug);
3460
3461 return 0;
3462 }
3463
move_module(struct module * mod,struct load_info * info)3464 static int move_module(struct module *mod, struct load_info *info)
3465 {
3466 int i;
3467 void *ptr;
3468
3469 /* Do the allocs. */
3470 ptr = module_alloc(mod->core_layout.size);
3471 /*
3472 * The pointer to this block is stored in the module structure
3473 * which is inside the block. Just mark it as not being a
3474 * leak.
3475 */
3476 kmemleak_not_leak(ptr);
3477 if (!ptr)
3478 return -ENOMEM;
3479
3480 memset(ptr, 0, mod->core_layout.size);
3481 mod->core_layout.base = ptr;
3482
3483 if (mod->init_layout.size) {
3484 ptr = module_alloc(mod->init_layout.size);
3485 /*
3486 * The pointer to this block is stored in the module structure
3487 * which is inside the block. This block doesn't need to be
3488 * scanned as it contains data and code that will be freed
3489 * after the module is initialized.
3490 */
3491 kmemleak_ignore(ptr);
3492 if (!ptr) {
3493 module_memfree(mod->core_layout.base);
3494 return -ENOMEM;
3495 }
3496 memset(ptr, 0, mod->init_layout.size);
3497 mod->init_layout.base = ptr;
3498 } else
3499 mod->init_layout.base = NULL;
3500
3501 /* Transfer each section which specifies SHF_ALLOC */
3502 pr_debug("final section addresses:\n");
3503 for (i = 0; i < info->hdr->e_shnum; i++) {
3504 void *dest;
3505 Elf_Shdr *shdr = &info->sechdrs[i];
3506
3507 if (!(shdr->sh_flags & SHF_ALLOC))
3508 continue;
3509
3510 if (shdr->sh_entsize & INIT_OFFSET_MASK)
3511 dest = mod->init_layout.base
3512 + (shdr->sh_entsize & ~INIT_OFFSET_MASK);
3513 else
3514 dest = mod->core_layout.base + shdr->sh_entsize;
3515
3516 if (shdr->sh_type != SHT_NOBITS)
3517 memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
3518 /* Update sh_addr to point to copy in image. */
3519 shdr->sh_addr = (unsigned long)dest;
3520 pr_debug("\t0x%lx %s\n",
3521 (long)shdr->sh_addr, info->secstrings + shdr->sh_name);
3522 }
3523
3524 return 0;
3525 }
3526
check_module_license_and_versions(struct module * mod)3527 static int check_module_license_and_versions(struct module *mod)
3528 {
3529 int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE);
3530
3531 /*
3532 * ndiswrapper is under GPL by itself, but loads proprietary modules.
3533 * Don't use add_taint_module(), as it would prevent ndiswrapper from
3534 * using GPL-only symbols it needs.
3535 */
3536 if (strcmp(mod->name, "ndiswrapper") == 0)
3537 add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
3538
3539 /* driverloader was caught wrongly pretending to be under GPL */
3540 if (strcmp(mod->name, "driverloader") == 0)
3541 add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
3542 LOCKDEP_NOW_UNRELIABLE);
3543
3544 /* lve claims to be GPL but upstream won't provide source */
3545 if (strcmp(mod->name, "lve") == 0)
3546 add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
3547 LOCKDEP_NOW_UNRELIABLE);
3548
3549 if (!prev_taint && test_taint(TAINT_PROPRIETARY_MODULE))
3550 pr_warn("%s: module license taints kernel.\n", mod->name);
3551
3552 #ifdef CONFIG_MODVERSIONS
3553 if ((mod->num_syms && !mod->crcs) ||
3554 (mod->num_gpl_syms && !mod->gpl_crcs)) {
3555 return try_to_force_load(mod,
3556 "no versions for exported symbols");
3557 }
3558 #endif
3559 return 0;
3560 }
3561
flush_module_icache(const struct module * mod)3562 static void flush_module_icache(const struct module *mod)
3563 {
3564 /*
3565 * Flush the instruction cache, since we've played with text.
3566 * Do it before processing of module parameters, so the module
3567 * can provide parameter accessor functions of its own.
3568 */
3569 if (mod->init_layout.base)
3570 flush_icache_range((unsigned long)mod->init_layout.base,
3571 (unsigned long)mod->init_layout.base
3572 + mod->init_layout.size);
3573 flush_icache_range((unsigned long)mod->core_layout.base,
3574 (unsigned long)mod->core_layout.base + mod->core_layout.size);
3575 }
3576
module_frob_arch_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)3577 int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
3578 Elf_Shdr *sechdrs,
3579 char *secstrings,
3580 struct module *mod)
3581 {
3582 return 0;
3583 }
3584
3585 /* module_blacklist is a comma-separated list of module names */
3586 static char *module_blacklist;
blacklisted(const char * module_name)3587 static bool blacklisted(const char *module_name)
3588 {
3589 const char *p;
3590 size_t len;
3591
3592 if (!module_blacklist)
3593 return false;
3594
3595 for (p = module_blacklist; *p; p += len) {
3596 len = strcspn(p, ",");
3597 if (strlen(module_name) == len && !memcmp(module_name, p, len))
3598 return true;
3599 if (p[len] == ',')
3600 len++;
3601 }
3602 return false;
3603 }
3604 core_param(module_blacklist, module_blacklist, charp, 0400);
3605
layout_and_allocate(struct load_info * info,int flags)3606 static struct module *layout_and_allocate(struct load_info *info, int flags)
3607 {
3608 struct module *mod;
3609 unsigned int ndx;
3610 int err;
3611
3612 err = check_modinfo(info->mod, info, flags);
3613 if (err)
3614 return ERR_PTR(err);
3615
3616 /* Allow arches to frob section contents and sizes. */
3617 err = module_frob_arch_sections(info->hdr, info->sechdrs,
3618 info->secstrings, info->mod);
3619 if (err < 0)
3620 return ERR_PTR(err);
3621
3622 err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
3623 info->secstrings, info->mod);
3624 if (err < 0)
3625 return ERR_PTR(err);
3626
3627 /* We will do a special allocation for per-cpu sections later. */
3628 info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
3629
3630 /*
3631 * Mark ro_after_init section with SHF_RO_AFTER_INIT so that
3632 * layout_sections() can put it in the right place.
3633 * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
3634 */
3635 ndx = find_sec(info, ".data..ro_after_init");
3636 if (ndx)
3637 info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
3638 /*
3639 * Mark the __jump_table section as ro_after_init as well: these data
3640 * structures are never modified, with the exception of entries that
3641 * refer to code in the __init section, which are annotated as such
3642 * at module load time.
3643 */
3644 ndx = find_sec(info, "__jump_table");
3645 if (ndx)
3646 info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
3647
3648 /*
3649 * Determine total sizes, and put offsets in sh_entsize. For now
3650 * this is done generically; there doesn't appear to be any
3651 * special cases for the architectures.
3652 */
3653 layout_sections(info->mod, info);
3654 layout_symtab(info->mod, info);
3655
3656 /* Allocate and move to the final place */
3657 err = move_module(info->mod, info);
3658 if (err)
3659 return ERR_PTR(err);
3660
3661 /* Module has been copied to its final place now: return it. */
3662 mod = (void *)info->sechdrs[info->index.mod].sh_addr;
3663 kmemleak_load_module(mod, info);
3664 return mod;
3665 }
3666
3667 /* mod is no longer valid after this! */
module_deallocate(struct module * mod,struct load_info * info)3668 static void module_deallocate(struct module *mod, struct load_info *info)
3669 {
3670 percpu_modfree(mod);
3671 module_arch_freeing_init(mod);
3672 trace_android_vh_set_memory_rw((unsigned long)mod->init_layout.base,
3673 (mod->init_layout.size)>>PAGE_SHIFT);
3674 trace_android_vh_set_memory_nx((unsigned long)mod->init_layout.base,
3675 (mod->init_layout.size)>>PAGE_SHIFT);
3676 module_memfree(mod->init_layout.base);
3677 trace_android_vh_set_memory_rw((unsigned long)mod->core_layout.base,
3678 (mod->core_layout.size)>>PAGE_SHIFT);
3679 trace_android_vh_set_memory_nx((unsigned long)mod->core_layout.base,
3680 (mod->core_layout.size)>>PAGE_SHIFT);
3681 module_memfree(mod->core_layout.base);
3682 }
3683
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)3684 int __weak module_finalize(const Elf_Ehdr *hdr,
3685 const Elf_Shdr *sechdrs,
3686 struct module *me)
3687 {
3688 return 0;
3689 }
3690
post_relocation(struct module * mod,const struct load_info * info)3691 static int post_relocation(struct module *mod, const struct load_info *info)
3692 {
3693 /* Sort exception table now relocations are done. */
3694 sort_extable(mod->extable, mod->extable + mod->num_exentries);
3695
3696 /* Copy relocated percpu area over. */
3697 percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
3698 info->sechdrs[info->index.pcpu].sh_size);
3699
3700 /* Setup kallsyms-specific fields. */
3701 add_kallsyms(mod, info);
3702
3703 /* Arch-specific module finalizing. */
3704 return module_finalize(info->hdr, info->sechdrs, mod);
3705 }
3706
3707 /* Is this module of this name done loading? No locks held. */
finished_loading(const char * name)3708 static bool finished_loading(const char *name)
3709 {
3710 struct module *mod;
3711 bool ret;
3712
3713 /*
3714 * The module_mutex should not be a heavily contended lock;
3715 * if we get the occasional sleep here, we'll go an extra iteration
3716 * in the wait_event_interruptible(), which is harmless.
3717 */
3718 sched_annotate_sleep();
3719 mutex_lock(&module_mutex);
3720 mod = find_module_all(name, strlen(name), true);
3721 ret = !mod || mod->state == MODULE_STATE_LIVE
3722 || mod->state == MODULE_STATE_GOING;
3723 mutex_unlock(&module_mutex);
3724
3725 return ret;
3726 }
3727
3728 /* Call module constructors. */
do_mod_ctors(struct module * mod)3729 static void do_mod_ctors(struct module *mod)
3730 {
3731 #ifdef CONFIG_CONSTRUCTORS
3732 unsigned long i;
3733
3734 for (i = 0; i < mod->num_ctors; i++)
3735 mod->ctors[i]();
3736 #endif
3737 }
3738
3739 /* For freeing module_init on success, in case kallsyms traversing */
3740 struct mod_initfree {
3741 struct llist_node node;
3742 void *module_init;
3743 };
3744
do_free_init(struct work_struct * w)3745 static void do_free_init(struct work_struct *w)
3746 {
3747 struct llist_node *pos, *n, *list;
3748 struct mod_initfree *initfree;
3749
3750 list = llist_del_all(&init_free_list);
3751
3752 synchronize_rcu();
3753
3754 llist_for_each_safe(pos, n, list) {
3755 initfree = container_of(pos, struct mod_initfree, node);
3756 module_memfree(initfree->module_init);
3757 kfree(initfree);
3758 }
3759 }
3760
3761 /*
3762 * This is where the real work happens.
3763 *
3764 * Keep it uninlined to provide a reliable breakpoint target, e.g. for the gdb
3765 * helper command 'lx-symbols'.
3766 */
do_init_module(struct module * mod)3767 static noinline int do_init_module(struct module *mod)
3768 {
3769 int ret = 0;
3770 struct mod_initfree *freeinit;
3771
3772 freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
3773 if (!freeinit) {
3774 ret = -ENOMEM;
3775 goto fail;
3776 }
3777 freeinit->module_init = mod->init_layout.base;
3778
3779 do_mod_ctors(mod);
3780 /* Start the module */
3781 if (mod->init != NULL)
3782 ret = do_one_initcall(mod->init);
3783 if (ret < 0) {
3784 goto fail_free_freeinit;
3785 }
3786 if (ret > 0) {
3787 pr_warn("%s: '%s'->init suspiciously returned %d, it should "
3788 "follow 0/-E convention\n"
3789 "%s: loading module anyway...\n",
3790 __func__, mod->name, ret, __func__);
3791 dump_stack();
3792 }
3793
3794 /* Now it's a first class citizen! */
3795 mod->state = MODULE_STATE_LIVE;
3796 blocking_notifier_call_chain(&module_notify_list,
3797 MODULE_STATE_LIVE, mod);
3798
3799 /* Delay uevent until module has finished its init routine */
3800 kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
3801
3802 /*
3803 * We need to finish all async code before the module init sequence
3804 * is done. This has potential to deadlock if synchronous module
3805 * loading is requested from async (which is not allowed!).
3806 *
3807 * See commit 0fdff3ec6d87 ("async, kmod: warn on synchronous
3808 * request_module() from async workers") for more details.
3809 */
3810 if (!mod->async_probe_requested)
3811 async_synchronize_full();
3812
3813 ftrace_free_mem(mod, mod->init_layout.base, mod->init_layout.base +
3814 mod->init_layout.size);
3815 mutex_lock(&module_mutex);
3816 /* Drop initial reference. */
3817 module_put(mod);
3818 trim_init_extable(mod);
3819 #ifdef CONFIG_KALLSYMS
3820 /* Switch to core kallsyms now init is done: kallsyms may be walking! */
3821 rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
3822 #endif
3823 module_enable_ro(mod, true);
3824 trace_android_vh_set_module_permit_after_init(mod);
3825 mod_tree_remove_init(mod);
3826 module_arch_freeing_init(mod);
3827 trace_android_vh_set_memory_rw((unsigned long)mod->init_layout.base,
3828 (mod->init_layout.size)>>PAGE_SHIFT);
3829 trace_android_vh_set_memory_nx((unsigned long)mod->init_layout.base,
3830 (mod->init_layout.size)>>PAGE_SHIFT);
3831 mod->init_layout.base = NULL;
3832 mod->init_layout.size = 0;
3833 mod->init_layout.ro_size = 0;
3834 mod->init_layout.ro_after_init_size = 0;
3835 mod->init_layout.text_size = 0;
3836 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
3837 /* .BTF is not SHF_ALLOC and will get removed, so sanitize pointer */
3838 mod->btf_data = NULL;
3839 #endif
3840 /*
3841 * We want to free module_init, but be aware that kallsyms may be
3842 * walking this with preempt disabled. In all the failure paths, we
3843 * call synchronize_rcu(), but we don't want to slow down the success
3844 * path. module_memfree() cannot be called in an interrupt, so do the
3845 * work and call synchronize_rcu() in a work queue.
3846 *
3847 * Note that module_alloc() on most architectures creates W+X page
3848 * mappings which won't be cleaned up until do_free_init() runs. Any
3849 * code such as mark_rodata_ro() which depends on those mappings to
3850 * be cleaned up needs to sync with the queued work - ie
3851 * rcu_barrier()
3852 */
3853 if (llist_add(&freeinit->node, &init_free_list))
3854 schedule_work(&init_free_wq);
3855
3856 mutex_unlock(&module_mutex);
3857 wake_up_all(&module_wq);
3858
3859 return 0;
3860
3861 fail_free_freeinit:
3862 kfree(freeinit);
3863 fail:
3864 /* Try to protect us from buggy refcounters. */
3865 mod->state = MODULE_STATE_GOING;
3866 synchronize_rcu();
3867 module_put(mod);
3868 blocking_notifier_call_chain(&module_notify_list,
3869 MODULE_STATE_GOING, mod);
3870 klp_module_going(mod);
3871 ftrace_release_mod(mod);
3872 free_module(mod);
3873 wake_up_all(&module_wq);
3874 return ret;
3875 }
3876
may_init_module(void)3877 static int may_init_module(void)
3878 {
3879 if (!capable(CAP_SYS_MODULE) || modules_disabled)
3880 return -EPERM;
3881
3882 return 0;
3883 }
3884
3885 /*
3886 * We try to place it in the list now to make sure it's unique before
3887 * we dedicate too many resources. In particular, temporary percpu
3888 * memory exhaustion.
3889 */
add_unformed_module(struct module * mod)3890 static int add_unformed_module(struct module *mod)
3891 {
3892 int err;
3893 struct module *old;
3894
3895 mod->state = MODULE_STATE_UNFORMED;
3896
3897 mutex_lock(&module_mutex);
3898 old = find_module_all(mod->name, strlen(mod->name), true);
3899 if (old != NULL) {
3900 if (old->state == MODULE_STATE_COMING
3901 || old->state == MODULE_STATE_UNFORMED) {
3902 /* Wait in case it fails to load. */
3903 mutex_unlock(&module_mutex);
3904 err = wait_event_interruptible(module_wq,
3905 finished_loading(mod->name));
3906 if (err)
3907 goto out_unlocked;
3908
3909 /* The module might have gone in the meantime. */
3910 mutex_lock(&module_mutex);
3911 old = find_module_all(mod->name, strlen(mod->name),
3912 true);
3913 }
3914
3915 /*
3916 * We are here only when the same module was being loaded. Do
3917 * not try to load it again right now. It prevents long delays
3918 * caused by serialized module load failures. It might happen
3919 * when more devices of the same type trigger load of
3920 * a particular module.
3921 */
3922 if (old && old->state == MODULE_STATE_LIVE)
3923 err = -EEXIST;
3924 else
3925 err = -EBUSY;
3926 goto out;
3927 }
3928 mod_update_bounds(mod);
3929 list_add_rcu(&mod->list, &modules);
3930 mod_tree_insert(mod);
3931 err = 0;
3932
3933 out:
3934 mutex_unlock(&module_mutex);
3935 out_unlocked:
3936 return err;
3937 }
3938
complete_formation(struct module * mod,struct load_info * info)3939 static int complete_formation(struct module *mod, struct load_info *info)
3940 {
3941 int err;
3942
3943 mutex_lock(&module_mutex);
3944
3945 /* Find duplicate symbols (must be called under lock). */
3946 err = verify_exported_symbols(mod);
3947 if (err < 0)
3948 goto out;
3949
3950 /* This relies on module_mutex for list integrity. */
3951 module_bug_finalize(info->hdr, info->sechdrs, mod);
3952
3953 module_enable_ro(mod, false);
3954 module_enable_nx(mod);
3955 module_enable_x(mod);
3956 trace_android_vh_set_module_permit_before_init(mod);
3957
3958 /*
3959 * Mark state as coming so strong_try_module_get() ignores us,
3960 * but kallsyms etc. can see us.
3961 */
3962 mod->state = MODULE_STATE_COMING;
3963 mutex_unlock(&module_mutex);
3964
3965 return 0;
3966
3967 out:
3968 mutex_unlock(&module_mutex);
3969 return err;
3970 }
3971
prepare_coming_module(struct module * mod)3972 static int prepare_coming_module(struct module *mod)
3973 {
3974 int err;
3975
3976 ftrace_module_enable(mod);
3977 err = klp_module_coming(mod);
3978 if (err)
3979 return err;
3980
3981 err = blocking_notifier_call_chain_robust(&module_notify_list,
3982 MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
3983 err = notifier_to_errno(err);
3984 if (err)
3985 klp_module_going(mod);
3986
3987 return err;
3988 }
3989
unknown_module_param_cb(char * param,char * val,const char * modname,void * arg)3990 static int unknown_module_param_cb(char *param, char *val, const char *modname,
3991 void *arg)
3992 {
3993 struct module *mod = arg;
3994 int ret;
3995
3996 if (strcmp(param, "async_probe") == 0) {
3997 mod->async_probe_requested = true;
3998 return 0;
3999 }
4000
4001 /* Check for magic 'dyndbg' arg */
4002 ret = ddebug_dyndbg_module_param_cb(param, val, modname);
4003 if (ret != 0)
4004 pr_warn("%s: unknown parameter '%s' ignored\n", modname, param);
4005 return 0;
4006 }
4007
4008 static void cfi_init(struct module *mod);
4009
4010 /*
4011 * Allocate and load the module: note that size of section 0 is always
4012 * zero, and we rely on this for optional sections.
4013 */
load_module(struct load_info * info,const char __user * uargs,int flags)4014 static int load_module(struct load_info *info, const char __user *uargs,
4015 int flags)
4016 {
4017 struct module *mod;
4018 long err = 0;
4019 char *after_dashes;
4020
4021 /*
4022 * Do the signature check (if any) first. All that
4023 * the signature check needs is info->len, it does
4024 * not need any of the section info. That can be
4025 * set up later. This will minimize the chances
4026 * of a corrupt module causing problems before
4027 * we even get to the signature check.
4028 *
4029 * The check will also adjust info->len by stripping
4030 * off the sig length at the end of the module, making
4031 * checks against info->len more correct.
4032 */
4033 err = module_sig_check(info, flags);
4034 if (err)
4035 goto free_copy;
4036
4037 /*
4038 * Do basic sanity checks against the ELF header and
4039 * sections.
4040 */
4041 err = elf_validity_check(info);
4042 if (err)
4043 goto free_copy;
4044
4045 /*
4046 * Everything checks out, so set up the section info
4047 * in the info structure.
4048 */
4049 err = setup_load_info(info, flags);
4050 if (err)
4051 goto free_copy;
4052
4053 /*
4054 * Now that we know we have the correct module name, check
4055 * if it's blacklisted.
4056 */
4057 if (blacklisted(info->name)) {
4058 err = -EPERM;
4059 pr_err("Module %s is blacklisted\n", info->name);
4060 goto free_copy;
4061 }
4062
4063 err = rewrite_section_headers(info, flags);
4064 if (err)
4065 goto free_copy;
4066
4067 /* Check module struct version now, before we try to use module. */
4068 if (!check_modstruct_version(info, info->mod)) {
4069 err = -ENOEXEC;
4070 goto free_copy;
4071 }
4072
4073 /* Figure out module layout, and allocate all the memory. */
4074 mod = layout_and_allocate(info, flags);
4075 if (IS_ERR(mod)) {
4076 err = PTR_ERR(mod);
4077 goto free_copy;
4078 }
4079
4080 audit_log_kern_module(mod->name);
4081
4082 /* Reserve our place in the list. */
4083 err = add_unformed_module(mod);
4084 if (err)
4085 goto free_module;
4086
4087 #ifdef CONFIG_MODULE_SIG
4088 mod->sig_ok = info->sig_ok;
4089 if (!mod->sig_ok) {
4090 pr_notice_once("%s: module verification failed: signature "
4091 "and/or required key missing - tainting "
4092 "kernel\n", mod->name);
4093 add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
4094 }
4095 #else
4096 mod->sig_ok = 0;
4097 #endif
4098
4099 /* To avoid stressing percpu allocator, do this once we're unique. */
4100 err = percpu_modalloc(mod, info);
4101 if (err)
4102 goto unlink_mod;
4103
4104 /* Now module is in final location, initialize linked lists, etc. */
4105 err = module_unload_init(mod);
4106 if (err)
4107 goto unlink_mod;
4108
4109 init_param_lock(mod);
4110
4111 /*
4112 * Now we've got everything in the final locations, we can
4113 * find optional sections.
4114 */
4115 err = find_module_sections(mod, info);
4116 if (err)
4117 goto free_unload;
4118
4119 err = check_module_license_and_versions(mod);
4120 if (err)
4121 goto free_unload;
4122
4123 /* Set up MODINFO_ATTR fields */
4124 setup_modinfo(mod, info);
4125
4126 /* Fix up syms, so that st_value is a pointer to location. */
4127 err = simplify_symbols(mod, info);
4128 if (err < 0)
4129 goto free_modinfo;
4130
4131 err = apply_relocations(mod, info);
4132 if (err < 0)
4133 goto free_modinfo;
4134
4135 err = post_relocation(mod, info);
4136 if (err < 0)
4137 goto free_modinfo;
4138
4139 flush_module_icache(mod);
4140
4141 /* Setup CFI for the module. */
4142 cfi_init(mod);
4143
4144 /* Now copy in args */
4145 mod->args = strndup_user(uargs, ~0UL >> 1);
4146 if (IS_ERR(mod->args)) {
4147 err = PTR_ERR(mod->args);
4148 goto free_arch_cleanup;
4149 }
4150
4151 init_build_id(mod, info);
4152 dynamic_debug_setup(mod, info->debug, info->num_debug);
4153
4154 /* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
4155 ftrace_module_init(mod);
4156
4157 /* Finally it's fully formed, ready to start executing. */
4158 err = complete_formation(mod, info);
4159 if (err)
4160 goto ddebug_cleanup;
4161
4162 err = prepare_coming_module(mod);
4163 if (err)
4164 goto bug_cleanup;
4165
4166 /* Module is ready to execute: parsing args may do that. */
4167 after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
4168 -32768, 32767, mod,
4169 unknown_module_param_cb);
4170 if (IS_ERR(after_dashes)) {
4171 err = PTR_ERR(after_dashes);
4172 goto coming_cleanup;
4173 } else if (after_dashes) {
4174 pr_warn("%s: parameters '%s' after `--' ignored\n",
4175 mod->name, after_dashes);
4176 }
4177
4178 /* Link in to sysfs. */
4179 err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
4180 if (err < 0)
4181 goto coming_cleanup;
4182
4183 if (is_livepatch_module(mod)) {
4184 err = copy_module_elf(mod, info);
4185 if (err < 0)
4186 goto sysfs_cleanup;
4187 }
4188
4189 /* Get rid of temporary copy. */
4190 free_copy(info);
4191
4192 /* Done! */
4193 trace_module_load(mod);
4194
4195 return do_init_module(mod);
4196
4197 sysfs_cleanup:
4198 mod_sysfs_teardown(mod);
4199 coming_cleanup:
4200 mod->state = MODULE_STATE_GOING;
4201 destroy_params(mod->kp, mod->num_kp);
4202 blocking_notifier_call_chain(&module_notify_list,
4203 MODULE_STATE_GOING, mod);
4204 klp_module_going(mod);
4205 bug_cleanup:
4206 mod->state = MODULE_STATE_GOING;
4207 /* module_bug_cleanup needs module_mutex protection */
4208 mutex_lock(&module_mutex);
4209 module_bug_cleanup(mod);
4210 mutex_unlock(&module_mutex);
4211
4212 ddebug_cleanup:
4213 ftrace_release_mod(mod);
4214 dynamic_debug_remove(mod, info->debug);
4215 synchronize_rcu();
4216 kfree(mod->args);
4217 free_arch_cleanup:
4218 cfi_cleanup(mod);
4219 module_arch_cleanup(mod);
4220 free_modinfo:
4221 free_modinfo(mod);
4222 free_unload:
4223 module_unload_free(mod);
4224 unlink_mod:
4225 mutex_lock(&module_mutex);
4226 /* Unlink carefully: kallsyms could be walking list. */
4227 list_del_rcu(&mod->list);
4228 mod_tree_remove(mod);
4229 wake_up_all(&module_wq);
4230 /* Wait for RCU-sched synchronizing before releasing mod->list. */
4231 synchronize_rcu();
4232 mutex_unlock(&module_mutex);
4233 free_module:
4234 /* Free lock-classes; relies on the preceding sync_rcu() */
4235 lockdep_free_key_range(mod->core_layout.base, mod->core_layout.size);
4236
4237 module_deallocate(mod, info);
4238 free_copy:
4239 free_copy(info);
4240 return err;
4241 }
4242
SYSCALL_DEFINE3(init_module,void __user *,umod,unsigned long,len,const char __user *,uargs)4243 SYSCALL_DEFINE3(init_module, void __user *, umod,
4244 unsigned long, len, const char __user *, uargs)
4245 {
4246 int err;
4247 struct load_info info = { };
4248
4249 err = may_init_module();
4250 if (err)
4251 return err;
4252
4253 pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
4254 umod, len, uargs);
4255
4256 err = copy_module_from_user(umod, len, &info);
4257 if (err)
4258 return err;
4259
4260 return load_module(&info, uargs, 0);
4261 }
4262
SYSCALL_DEFINE3(finit_module,int,fd,const char __user *,uargs,int,flags)4263 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
4264 {
4265 struct load_info info = { };
4266 void *hdr = NULL;
4267 int err;
4268
4269 err = may_init_module();
4270 if (err)
4271 return err;
4272
4273 pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
4274
4275 if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
4276 |MODULE_INIT_IGNORE_VERMAGIC))
4277 return -EINVAL;
4278
4279 err = kernel_read_file_from_fd(fd, 0, &hdr, INT_MAX, NULL,
4280 READING_MODULE);
4281 if (err < 0)
4282 return err;
4283 info.hdr = hdr;
4284 info.len = err;
4285
4286 return load_module(&info, uargs, flags);
4287 }
4288
within(unsigned long addr,void * start,unsigned long size)4289 static inline int within(unsigned long addr, void *start, unsigned long size)
4290 {
4291 return ((void *)addr >= start && (void *)addr < start + size);
4292 }
4293
4294 #ifdef CONFIG_KALLSYMS
4295 /*
4296 * This ignores the intensely annoying "mapping symbols" found
4297 * in ARM ELF files: $a, $t and $d.
4298 */
is_arm_mapping_symbol(const char * str)4299 static inline int is_arm_mapping_symbol(const char *str)
4300 {
4301 if (str[0] == '.' && str[1] == 'L')
4302 return true;
4303 return str[0] == '$' && strchr("axtd", str[1])
4304 && (str[2] == '\0' || str[2] == '.');
4305 }
4306
kallsyms_symbol_name(struct mod_kallsyms * kallsyms,unsigned int symnum)4307 static const char *kallsyms_symbol_name(struct mod_kallsyms *kallsyms, unsigned int symnum)
4308 {
4309 return kallsyms->strtab + kallsyms->symtab[symnum].st_name;
4310 }
4311
4312 /*
4313 * Given a module and address, find the corresponding symbol and return its name
4314 * while providing its size and offset if needed.
4315 */
find_kallsyms_symbol(struct module * mod,unsigned long addr,unsigned long * size,unsigned long * offset)4316 static const char *find_kallsyms_symbol(struct module *mod,
4317 unsigned long addr,
4318 unsigned long *size,
4319 unsigned long *offset)
4320 {
4321 unsigned int i, best = 0;
4322 unsigned long nextval, bestval;
4323 struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
4324
4325 /* At worse, next value is at end of module */
4326 if (within_module_init(addr, mod))
4327 nextval = (unsigned long)mod->init_layout.base+mod->init_layout.text_size;
4328 else
4329 nextval = (unsigned long)mod->core_layout.base+mod->core_layout.text_size;
4330
4331 bestval = kallsyms_symbol_value(&kallsyms->symtab[best]);
4332
4333 /*
4334 * Scan for closest preceding symbol, and next symbol. (ELF
4335 * starts real symbols at 1).
4336 */
4337 for (i = 1; i < kallsyms->num_symtab; i++) {
4338 const Elf_Sym *sym = &kallsyms->symtab[i];
4339 unsigned long thisval = kallsyms_symbol_value(sym);
4340
4341 if (sym->st_shndx == SHN_UNDEF)
4342 continue;
4343
4344 /*
4345 * We ignore unnamed symbols: they're uninformative
4346 * and inserted at a whim.
4347 */
4348 if (*kallsyms_symbol_name(kallsyms, i) == '\0'
4349 || is_arm_mapping_symbol(kallsyms_symbol_name(kallsyms, i)))
4350 continue;
4351
4352 if (thisval <= addr && thisval > bestval) {
4353 best = i;
4354 bestval = thisval;
4355 }
4356 if (thisval > addr && thisval < nextval)
4357 nextval = thisval;
4358 }
4359
4360 if (!best)
4361 return NULL;
4362
4363 if (size)
4364 *size = nextval - bestval;
4365 if (offset)
4366 *offset = addr - bestval;
4367
4368 return kallsyms_symbol_name(kallsyms, best);
4369 }
4370
dereference_module_function_descriptor(struct module * mod,void * ptr)4371 void * __weak dereference_module_function_descriptor(struct module *mod,
4372 void *ptr)
4373 {
4374 return ptr;
4375 }
4376
4377 /*
4378 * For kallsyms to ask for address resolution. NULL means not found. Careful
4379 * not to lock to avoid deadlock on oopses, simply disable preemption.
4380 */
module_address_lookup(unsigned long addr,unsigned long * size,unsigned long * offset,char ** modname,const unsigned char ** modbuildid,char * namebuf)4381 const char *module_address_lookup(unsigned long addr,
4382 unsigned long *size,
4383 unsigned long *offset,
4384 char **modname,
4385 const unsigned char **modbuildid,
4386 char *namebuf)
4387 {
4388 const char *ret = NULL;
4389 struct module *mod;
4390
4391 preempt_disable();
4392 mod = __module_address(addr);
4393 if (mod) {
4394 if (modname)
4395 *modname = mod->name;
4396 if (modbuildid) {
4397 #if IS_ENABLED(CONFIG_STACKTRACE_BUILD_ID)
4398 *modbuildid = mod->build_id;
4399 #else
4400 *modbuildid = NULL;
4401 #endif
4402 }
4403
4404 ret = find_kallsyms_symbol(mod, addr, size, offset);
4405 }
4406 /* Make a copy in here where it's safe */
4407 if (ret) {
4408 strncpy(namebuf, ret, KSYM_NAME_LEN - 1);
4409 ret = namebuf;
4410 }
4411 preempt_enable();
4412
4413 return ret;
4414 }
4415
lookup_module_symbol_name(unsigned long addr,char * symname)4416 int lookup_module_symbol_name(unsigned long addr, char *symname)
4417 {
4418 struct module *mod;
4419
4420 preempt_disable();
4421 list_for_each_entry_rcu(mod, &modules, list) {
4422 if (mod->state == MODULE_STATE_UNFORMED)
4423 continue;
4424 if (within_module(addr, mod)) {
4425 const char *sym;
4426
4427 sym = find_kallsyms_symbol(mod, addr, NULL, NULL);
4428 if (!sym)
4429 goto out;
4430
4431 strlcpy(symname, sym, KSYM_NAME_LEN);
4432 preempt_enable();
4433 return 0;
4434 }
4435 }
4436 out:
4437 preempt_enable();
4438 return -ERANGE;
4439 }
4440
lookup_module_symbol_attrs(unsigned long addr,unsigned long * size,unsigned long * offset,char * modname,char * name)4441 int lookup_module_symbol_attrs(unsigned long addr, unsigned long *size,
4442 unsigned long *offset, char *modname, char *name)
4443 {
4444 struct module *mod;
4445
4446 preempt_disable();
4447 list_for_each_entry_rcu(mod, &modules, list) {
4448 if (mod->state == MODULE_STATE_UNFORMED)
4449 continue;
4450 if (within_module(addr, mod)) {
4451 const char *sym;
4452
4453 sym = find_kallsyms_symbol(mod, addr, size, offset);
4454 if (!sym)
4455 goto out;
4456 if (modname)
4457 strlcpy(modname, mod->name, MODULE_NAME_LEN);
4458 if (name)
4459 strlcpy(name, sym, KSYM_NAME_LEN);
4460 preempt_enable();
4461 return 0;
4462 }
4463 }
4464 out:
4465 preempt_enable();
4466 return -ERANGE;
4467 }
4468
module_get_kallsym(unsigned int symnum,unsigned long * value,char * type,char * name,char * module_name,int * exported)4469 int module_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
4470 char *name, char *module_name, int *exported)
4471 {
4472 struct module *mod;
4473
4474 preempt_disable();
4475 list_for_each_entry_rcu(mod, &modules, list) {
4476 struct mod_kallsyms *kallsyms;
4477
4478 if (mod->state == MODULE_STATE_UNFORMED)
4479 continue;
4480 kallsyms = rcu_dereference_sched(mod->kallsyms);
4481 if (symnum < kallsyms->num_symtab) {
4482 const Elf_Sym *sym = &kallsyms->symtab[symnum];
4483
4484 *value = kallsyms_symbol_value(sym);
4485 *type = kallsyms->typetab[symnum];
4486 strlcpy(name, kallsyms_symbol_name(kallsyms, symnum), KSYM_NAME_LEN);
4487 strlcpy(module_name, mod->name, MODULE_NAME_LEN);
4488 *exported = is_exported(name, *value, mod);
4489 preempt_enable();
4490 return 0;
4491 }
4492 symnum -= kallsyms->num_symtab;
4493 }
4494 preempt_enable();
4495 return -ERANGE;
4496 }
4497
4498 /* Given a module and name of symbol, find and return the symbol's value */
find_kallsyms_symbol_value(struct module * mod,const char * name)4499 static unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)
4500 {
4501 unsigned int i;
4502 struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
4503
4504 for (i = 0; i < kallsyms->num_symtab; i++) {
4505 const Elf_Sym *sym = &kallsyms->symtab[i];
4506
4507 if (strcmp(name, kallsyms_symbol_name(kallsyms, i)) == 0 &&
4508 sym->st_shndx != SHN_UNDEF)
4509 return kallsyms_symbol_value(sym);
4510 }
4511 return 0;
4512 }
4513
4514 /* Look for this name: can be of form module:name. */
module_kallsyms_lookup_name(const char * name)4515 unsigned long module_kallsyms_lookup_name(const char *name)
4516 {
4517 struct module *mod;
4518 char *colon;
4519 unsigned long ret = 0;
4520
4521 /* Don't lock: we're in enough trouble already. */
4522 preempt_disable();
4523 if ((colon = strnchr(name, MODULE_NAME_LEN, ':')) != NULL) {
4524 if ((mod = find_module_all(name, colon - name, false)) != NULL)
4525 ret = find_kallsyms_symbol_value(mod, colon+1);
4526 } else {
4527 list_for_each_entry_rcu(mod, &modules, list) {
4528 if (mod->state == MODULE_STATE_UNFORMED)
4529 continue;
4530 if ((ret = find_kallsyms_symbol_value(mod, name)) != 0)
4531 break;
4532 }
4533 }
4534 preempt_enable();
4535 return ret;
4536 }
4537
module_kallsyms_on_each_symbol(int (* fn)(void *,const char *,struct module *,unsigned long),void * data)4538 int module_kallsyms_on_each_symbol(int (*fn)(void *, const char *,
4539 struct module *, unsigned long),
4540 void *data)
4541 {
4542 struct module *mod;
4543 unsigned int i;
4544 int ret = 0;
4545
4546 mutex_lock(&module_mutex);
4547 list_for_each_entry(mod, &modules, list) {
4548 /* We hold module_mutex: no need for rcu_dereference_sched */
4549 struct mod_kallsyms *kallsyms = mod->kallsyms;
4550
4551 if (mod->state == MODULE_STATE_UNFORMED)
4552 continue;
4553 for (i = 0; i < kallsyms->num_symtab; i++) {
4554 const Elf_Sym *sym = &kallsyms->symtab[i];
4555
4556 if (sym->st_shndx == SHN_UNDEF)
4557 continue;
4558
4559 ret = fn(data, kallsyms_symbol_name(kallsyms, i),
4560 mod, kallsyms_symbol_value(sym));
4561 if (ret != 0)
4562 goto out;
4563 }
4564 }
4565 out:
4566 mutex_unlock(&module_mutex);
4567 return ret;
4568 }
4569 #endif /* CONFIG_KALLSYMS */
4570
cfi_init(struct module * mod)4571 static void cfi_init(struct module *mod)
4572 {
4573 #ifdef CONFIG_CFI_CLANG
4574 initcall_t *init;
4575 exitcall_t *exit;
4576
4577 rcu_read_lock_sched();
4578 mod->cfi_check = (cfi_check_fn)
4579 find_kallsyms_symbol_value(mod, "__cfi_check");
4580 init = (initcall_t *)
4581 find_kallsyms_symbol_value(mod, "__cfi_jt_init_module");
4582 exit = (exitcall_t *)
4583 find_kallsyms_symbol_value(mod, "__cfi_jt_cleanup_module");
4584 rcu_read_unlock_sched();
4585
4586 /* Fix init/exit functions to point to the CFI jump table */
4587 if (init)
4588 mod->init = *init;
4589 #ifdef CONFIG_MODULE_UNLOAD
4590 if (exit)
4591 mod->exit = *exit;
4592 #endif
4593
4594 cfi_module_add(mod, module_addr_min);
4595 #endif
4596 }
4597
cfi_cleanup(struct module * mod)4598 static void cfi_cleanup(struct module *mod)
4599 {
4600 #ifdef CONFIG_CFI_CLANG
4601 cfi_module_remove(mod, module_addr_min);
4602 #endif
4603 }
4604
4605 /* Maximum number of characters written by module_flags() */
4606 #define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)
4607
4608 /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
module_flags(struct module * mod,char * buf)4609 static char *module_flags(struct module *mod, char *buf)
4610 {
4611 int bx = 0;
4612
4613 BUG_ON(mod->state == MODULE_STATE_UNFORMED);
4614 if (mod->taints ||
4615 mod->state == MODULE_STATE_GOING ||
4616 mod->state == MODULE_STATE_COMING) {
4617 buf[bx++] = '(';
4618 bx += module_flags_taint(mod, buf + bx);
4619 /* Show a - for module-is-being-unloaded */
4620 if (mod->state == MODULE_STATE_GOING)
4621 buf[bx++] = '-';
4622 /* Show a + for module-is-being-loaded */
4623 if (mod->state == MODULE_STATE_COMING)
4624 buf[bx++] = '+';
4625 buf[bx++] = ')';
4626 }
4627 buf[bx] = '\0';
4628
4629 return buf;
4630 }
4631
4632 #ifdef CONFIG_PROC_FS
4633 /* Called by the /proc file system to return a list of modules. */
m_start(struct seq_file * m,loff_t * pos)4634 static void *m_start(struct seq_file *m, loff_t *pos)
4635 {
4636 mutex_lock(&module_mutex);
4637 return seq_list_start(&modules, *pos);
4638 }
4639
m_next(struct seq_file * m,void * p,loff_t * pos)4640 static void *m_next(struct seq_file *m, void *p, loff_t *pos)
4641 {
4642 return seq_list_next(p, &modules, pos);
4643 }
4644
m_stop(struct seq_file * m,void * p)4645 static void m_stop(struct seq_file *m, void *p)
4646 {
4647 mutex_unlock(&module_mutex);
4648 }
4649
m_show(struct seq_file * m,void * p)4650 static int m_show(struct seq_file *m, void *p)
4651 {
4652 struct module *mod = list_entry(p, struct module, list);
4653 char buf[MODULE_FLAGS_BUF_SIZE];
4654 void *value;
4655
4656 /* We always ignore unformed modules. */
4657 if (mod->state == MODULE_STATE_UNFORMED)
4658 return 0;
4659
4660 seq_printf(m, "%s %u",
4661 mod->name, mod->init_layout.size + mod->core_layout.size);
4662 print_unload_info(m, mod);
4663
4664 /* Informative for users. */
4665 seq_printf(m, " %s",
4666 mod->state == MODULE_STATE_GOING ? "Unloading" :
4667 mod->state == MODULE_STATE_COMING ? "Loading" :
4668 "Live");
4669 /* Used by oprofile and other similar tools. */
4670 value = m->private ? NULL : mod->core_layout.base;
4671 seq_printf(m, " 0x%px", value);
4672
4673 /* Taints info */
4674 if (mod->taints)
4675 seq_printf(m, " %s", module_flags(mod, buf));
4676
4677 seq_puts(m, "\n");
4678 return 0;
4679 }
4680
4681 /*
4682 * Format: modulename size refcount deps address
4683 *
4684 * Where refcount is a number or -, and deps is a comma-separated list
4685 * of depends or -.
4686 */
4687 static const struct seq_operations modules_op = {
4688 .start = m_start,
4689 .next = m_next,
4690 .stop = m_stop,
4691 .show = m_show
4692 };
4693
4694 /*
4695 * This also sets the "private" pointer to non-NULL if the
4696 * kernel pointers should be hidden (so you can just test
4697 * "m->private" to see if you should keep the values private).
4698 *
4699 * We use the same logic as for /proc/kallsyms.
4700 */
modules_open(struct inode * inode,struct file * file)4701 static int modules_open(struct inode *inode, struct file *file)
4702 {
4703 int err = seq_open(file, &modules_op);
4704
4705 if (!err) {
4706 struct seq_file *m = file->private_data;
4707 m->private = kallsyms_show_value(file->f_cred) ? NULL : (void *)8ul;
4708 }
4709
4710 return err;
4711 }
4712
4713 static const struct proc_ops modules_proc_ops = {
4714 .proc_flags = PROC_ENTRY_PERMANENT,
4715 .proc_open = modules_open,
4716 .proc_read = seq_read,
4717 .proc_lseek = seq_lseek,
4718 .proc_release = seq_release,
4719 };
4720
proc_modules_init(void)4721 static int __init proc_modules_init(void)
4722 {
4723 proc_create("modules", 0, NULL, &modules_proc_ops);
4724 return 0;
4725 }
4726 module_init(proc_modules_init);
4727 #endif
4728
4729 /* Given an address, look for it in the module exception tables. */
search_module_extables(unsigned long addr)4730 const struct exception_table_entry *search_module_extables(unsigned long addr)
4731 {
4732 const struct exception_table_entry *e = NULL;
4733 struct module *mod;
4734
4735 preempt_disable();
4736 mod = __module_address(addr);
4737 if (!mod)
4738 goto out;
4739
4740 if (!mod->num_exentries)
4741 goto out;
4742
4743 e = search_extable(mod->extable,
4744 mod->num_exentries,
4745 addr);
4746 out:
4747 preempt_enable();
4748
4749 /*
4750 * Now, if we found one, we are running inside it now, hence
4751 * we cannot unload the module, hence no refcnt needed.
4752 */
4753 return e;
4754 }
4755
4756 /**
4757 * is_module_address() - is this address inside a module?
4758 * @addr: the address to check.
4759 *
4760 * See is_module_text_address() if you simply want to see if the address
4761 * is code (not data).
4762 */
is_module_address(unsigned long addr)4763 bool is_module_address(unsigned long addr)
4764 {
4765 bool ret;
4766
4767 preempt_disable();
4768 ret = __module_address(addr) != NULL;
4769 preempt_enable();
4770
4771 return ret;
4772 }
4773
4774 /**
4775 * __module_address() - get the module which contains an address.
4776 * @addr: the address.
4777 *
4778 * Must be called with preempt disabled or module mutex held so that
4779 * module doesn't get freed during this.
4780 */
__module_address(unsigned long addr)4781 struct module *__module_address(unsigned long addr)
4782 {
4783 struct module *mod;
4784
4785 if (addr < module_addr_min || addr > module_addr_max)
4786 return NULL;
4787
4788 module_assert_mutex_or_preempt();
4789
4790 mod = mod_find(addr);
4791 if (mod) {
4792 BUG_ON(!within_module(addr, mod));
4793 if (mod->state == MODULE_STATE_UNFORMED)
4794 mod = NULL;
4795 }
4796 return mod;
4797 }
4798
4799 /**
4800 * is_module_text_address() - is this address inside module code?
4801 * @addr: the address to check.
4802 *
4803 * See is_module_address() if you simply want to see if the address is
4804 * anywhere in a module. See kernel_text_address() for testing if an
4805 * address corresponds to kernel or module code.
4806 */
is_module_text_address(unsigned long addr)4807 bool is_module_text_address(unsigned long addr)
4808 {
4809 bool ret;
4810
4811 preempt_disable();
4812 ret = __module_text_address(addr) != NULL;
4813 preempt_enable();
4814
4815 return ret;
4816 }
4817
4818 /**
4819 * __module_text_address() - get the module whose code contains an address.
4820 * @addr: the address.
4821 *
4822 * Must be called with preempt disabled or module mutex held so that
4823 * module doesn't get freed during this.
4824 */
__module_text_address(unsigned long addr)4825 struct module *__module_text_address(unsigned long addr)
4826 {
4827 struct module *mod = __module_address(addr);
4828 if (mod) {
4829 /* Make sure it's within the text section. */
4830 if (!within(addr, mod->init_layout.base, mod->init_layout.text_size)
4831 && !within(addr, mod->core_layout.base, mod->core_layout.text_size))
4832 mod = NULL;
4833 }
4834 return mod;
4835 }
4836
4837 /* Don't grab lock, we're oopsing. */
print_modules(void)4838 void print_modules(void)
4839 {
4840 struct module *mod;
4841 char buf[MODULE_FLAGS_BUF_SIZE];
4842
4843 printk(KERN_DEFAULT "Modules linked in:");
4844 /* Most callers should already have preempt disabled, but make sure */
4845 preempt_disable();
4846 list_for_each_entry_rcu(mod, &modules, list) {
4847 if (mod->state == MODULE_STATE_UNFORMED)
4848 continue;
4849 pr_cont(" %s%s", mod->name, module_flags(mod, buf));
4850 }
4851 preempt_enable();
4852 if (last_unloaded_module[0])
4853 pr_cont(" [last unloaded: %s]", last_unloaded_module);
4854 pr_cont("\n");
4855 }
4856
4857 #ifdef CONFIG_ANDROID_DEBUG_SYMBOLS
android_debug_for_each_module(int (* fn)(const char * mod_name,void * mod_addr,void * data),void * data)4858 void android_debug_for_each_module(int (*fn)(const char *mod_name, void *mod_addr, void *data),
4859 void *data)
4860 {
4861 struct module *module;
4862 preempt_disable();
4863 list_for_each_entry_rcu(module, &modules, list) {
4864 if (fn(module->name, module->core_layout.base, data))
4865 goto out;
4866 }
4867 out:
4868 preempt_enable();
4869 }
4870 EXPORT_SYMBOL_NS_GPL(android_debug_for_each_module, MINIDUMP);
4871 #endif
4872
4873 #ifdef CONFIG_MODVERSIONS
4874 /*
4875 * Generate the signature for all relevant module structures here.
4876 * If these change, we don't want to try to parse the module.
4877 */
module_layout(struct module * mod,struct modversion_info * ver,struct kernel_param * kp,struct kernel_symbol * ks,struct tracepoint * const * tp)4878 void module_layout(struct module *mod,
4879 struct modversion_info *ver,
4880 struct kernel_param *kp,
4881 struct kernel_symbol *ks,
4882 struct tracepoint * const *tp)
4883 {
4884 }
4885 EXPORT_SYMBOL(module_layout);
4886 #endif
4887