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  * Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
6  */
7 
8 #define INCLUDE_VERMAGIC
9 
10 #include <linux/export.h>
11 #include <linux/extable.h>
12 #include <linux/moduleloader.h>
13 #include <linux/module_signature.h>
14 #include <linux/trace_events.h>
15 #include <linux/init.h>
16 #include <linux/kallsyms.h>
17 #include <linux/buildid.h>
18 #include <linux/fs.h>
19 #include <linux/kernel.h>
20 #include <linux/kernel_read_file.h>
21 #include <linux/kstrtox.h>
22 #include <linux/slab.h>
23 #include <linux/vmalloc.h>
24 #include <linux/elf.h>
25 #include <linux/seq_file.h>
26 #include <linux/syscalls.h>
27 #include <linux/fcntl.h>
28 #include <linux/rcupdate.h>
29 #include <linux/capability.h>
30 #include <linux/cpu.h>
31 #include <linux/moduleparam.h>
32 #include <linux/errno.h>
33 #include <linux/err.h>
34 #include <linux/vermagic.h>
35 #include <linux/notifier.h>
36 #include <linux/sched.h>
37 #include <linux/device.h>
38 #include <linux/string.h>
39 #include <linux/mutex.h>
40 #include <linux/rculist.h>
41 #include <linux/uaccess.h>
42 #include <asm/cacheflush.h>
43 #include <linux/set_memory.h>
44 #include <asm/mmu_context.h>
45 #include <linux/license.h>
46 #include <asm/sections.h>
47 #include <linux/tracepoint.h>
48 #include <linux/ftrace.h>
49 #include <linux/livepatch.h>
50 #include <linux/async.h>
51 #include <linux/percpu.h>
52 #include <linux/kmemleak.h>
53 #include <linux/jump_label.h>
54 #include <linux/pfn.h>
55 #include <linux/bsearch.h>
56 #include <linux/dynamic_debug.h>
57 #include <linux/audit.h>
58 #include <linux/cfi.h>
59 #include <linux/debugfs.h>
60 #include <uapi/linux/module.h>
61 #include "internal.h"
62 
63 #define CREATE_TRACE_POINTS
64 #include <trace/events/module.h>
65 
66 /*
67  * Mutex protects:
68  * 1) List of modules (also safely readable with preempt_disable),
69  * 2) module_use links,
70  * 3) mod_tree.addr_min/mod_tree.addr_max.
71  * (delete and add uses RCU list operations).
72  */
73 DEFINE_MUTEX(module_mutex);
74 LIST_HEAD(modules);
75 
76 /* Work queue for freeing init sections in success case */
77 static void do_free_init(struct work_struct *w);
78 static DECLARE_WORK(init_free_wq, do_free_init);
79 static LLIST_HEAD(init_free_list);
80 
81 struct mod_tree_root mod_tree __cacheline_aligned = {
82 	.addr_min = -1UL,
83 };
84 
85 struct symsearch {
86 	const struct kernel_symbol *start, *stop;
87 	const s32 *crcs;
88 	enum mod_license license;
89 };
90 
91 /*
92  * Bounds of module memory, for speeding up __module_address.
93  * Protected by module_mutex.
94  */
__mod_update_bounds(enum mod_mem_type type __maybe_unused,void * base,unsigned int size,struct mod_tree_root * tree)95 static void __mod_update_bounds(enum mod_mem_type type __maybe_unused, void *base,
96 				unsigned int size, struct mod_tree_root *tree)
97 {
98 	unsigned long min = (unsigned long)base;
99 	unsigned long max = min + size;
100 
101 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
102 	if (mod_mem_type_is_core_data(type)) {
103 		if (min < tree->data_addr_min)
104 			tree->data_addr_min = min;
105 		if (max > tree->data_addr_max)
106 			tree->data_addr_max = max;
107 		return;
108 	}
109 #endif
110 	if (min < tree->addr_min)
111 		tree->addr_min = min;
112 	if (max > tree->addr_max)
113 		tree->addr_max = max;
114 }
115 
mod_update_bounds(struct module * mod)116 static void mod_update_bounds(struct module *mod)
117 {
118 	for_each_mod_mem_type(type) {
119 		struct module_memory *mod_mem = &mod->mem[type];
120 
121 		if (mod_mem->size)
122 			__mod_update_bounds(type, mod_mem->base, mod_mem->size, &mod_tree);
123 	}
124 }
125 
126 /* Block module loading/unloading? */
127 int modules_disabled;
128 core_param(nomodule, modules_disabled, bint, 0);
129 
130 /* Waiting for a module to finish initializing? */
131 static DECLARE_WAIT_QUEUE_HEAD(module_wq);
132 
133 static BLOCKING_NOTIFIER_HEAD(module_notify_list);
134 
register_module_notifier(struct notifier_block * nb)135 int register_module_notifier(struct notifier_block *nb)
136 {
137 	return blocking_notifier_chain_register(&module_notify_list, nb);
138 }
139 EXPORT_SYMBOL(register_module_notifier);
140 
unregister_module_notifier(struct notifier_block * nb)141 int unregister_module_notifier(struct notifier_block *nb)
142 {
143 	return blocking_notifier_chain_unregister(&module_notify_list, nb);
144 }
145 EXPORT_SYMBOL(unregister_module_notifier);
146 
147 /*
148  * We require a truly strong try_module_get(): 0 means success.
149  * Otherwise an error is returned due to ongoing or failed
150  * initialization etc.
151  */
strong_try_module_get(struct module * mod)152 static inline int strong_try_module_get(struct module *mod)
153 {
154 	BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
155 	if (mod && mod->state == MODULE_STATE_COMING)
156 		return -EBUSY;
157 	if (try_module_get(mod))
158 		return 0;
159 	else
160 		return -ENOENT;
161 }
162 
add_taint_module(struct module * mod,unsigned flag,enum lockdep_ok lockdep_ok)163 static inline void add_taint_module(struct module *mod, unsigned flag,
164 				    enum lockdep_ok lockdep_ok)
165 {
166 	add_taint(flag, lockdep_ok);
167 	set_bit(flag, &mod->taints);
168 }
169 
170 /*
171  * A thread that wants to hold a reference to a module only while it
172  * is running can call this to safely exit.
173  */
__module_put_and_kthread_exit(struct module * mod,long code)174 void __noreturn __module_put_and_kthread_exit(struct module *mod, long code)
175 {
176 	module_put(mod);
177 	kthread_exit(code);
178 }
179 EXPORT_SYMBOL(__module_put_and_kthread_exit);
180 
181 /* Find a module section: 0 means not found. */
find_sec(const struct load_info * info,const char * name)182 static unsigned int find_sec(const struct load_info *info, const char *name)
183 {
184 	unsigned int i;
185 
186 	for (i = 1; i < info->hdr->e_shnum; i++) {
187 		Elf_Shdr *shdr = &info->sechdrs[i];
188 		/* Alloc bit cleared means "ignore it." */
189 		if ((shdr->sh_flags & SHF_ALLOC)
190 		    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
191 			return i;
192 	}
193 	return 0;
194 }
195 
196 /* Find a module section, or NULL. */
section_addr(const struct load_info * info,const char * name)197 static void *section_addr(const struct load_info *info, const char *name)
198 {
199 	/* Section 0 has sh_addr 0. */
200 	return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
201 }
202 
203 /* 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)204 static void *section_objs(const struct load_info *info,
205 			  const char *name,
206 			  size_t object_size,
207 			  unsigned int *num)
208 {
209 	unsigned int sec = find_sec(info, name);
210 
211 	/* Section 0 has sh_addr 0 and sh_size 0. */
212 	*num = info->sechdrs[sec].sh_size / object_size;
213 	return (void *)info->sechdrs[sec].sh_addr;
214 }
215 
216 /* Find a module section: 0 means not found. Ignores SHF_ALLOC flag. */
find_any_sec(const struct load_info * info,const char * name)217 static unsigned int find_any_sec(const struct load_info *info, const char *name)
218 {
219 	unsigned int i;
220 
221 	for (i = 1; i < info->hdr->e_shnum; i++) {
222 		Elf_Shdr *shdr = &info->sechdrs[i];
223 		if (strcmp(info->secstrings + shdr->sh_name, name) == 0)
224 			return i;
225 	}
226 	return 0;
227 }
228 
229 /*
230  * Find a module section, or NULL. Fill in number of "objects" in section.
231  * Ignores SHF_ALLOC flag.
232  */
any_section_objs(const struct load_info * info,const char * name,size_t object_size,unsigned int * num)233 static __maybe_unused void *any_section_objs(const struct load_info *info,
234 					     const char *name,
235 					     size_t object_size,
236 					     unsigned int *num)
237 {
238 	unsigned int sec = find_any_sec(info, name);
239 
240 	/* Section 0 has sh_addr 0 and sh_size 0. */
241 	*num = info->sechdrs[sec].sh_size / object_size;
242 	return (void *)info->sechdrs[sec].sh_addr;
243 }
244 
245 #ifndef CONFIG_MODVERSIONS
246 #define symversion(base, idx) NULL
247 #else
248 #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
249 #endif
250 
kernel_symbol_name(const struct kernel_symbol * sym)251 static const char *kernel_symbol_name(const struct kernel_symbol *sym)
252 {
253 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
254 	return offset_to_ptr(&sym->name_offset);
255 #else
256 	return sym->name;
257 #endif
258 }
259 
kernel_symbol_namespace(const struct kernel_symbol * sym)260 static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
261 {
262 #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
263 	if (!sym->namespace_offset)
264 		return NULL;
265 	return offset_to_ptr(&sym->namespace_offset);
266 #else
267 	return sym->namespace;
268 #endif
269 }
270 
cmp_name(const void * name,const void * sym)271 int cmp_name(const void *name, const void *sym)
272 {
273 	return strcmp(name, kernel_symbol_name(sym));
274 }
275 
find_exported_symbol_in_section(const struct symsearch * syms,struct module * owner,struct find_symbol_arg * fsa)276 static bool find_exported_symbol_in_section(const struct symsearch *syms,
277 					    struct module *owner,
278 					    struct find_symbol_arg *fsa)
279 {
280 	struct kernel_symbol *sym;
281 
282 	if (!fsa->gplok && syms->license == GPL_ONLY)
283 		return false;
284 
285 	sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
286 			sizeof(struct kernel_symbol), cmp_name);
287 	if (!sym)
288 		return false;
289 
290 	fsa->owner = owner;
291 	fsa->crc = symversion(syms->crcs, sym - syms->start);
292 	fsa->sym = sym;
293 	fsa->license = syms->license;
294 
295 	return true;
296 }
297 
298 /*
299  * Find an exported symbol and return it, along with, (optional) crc and
300  * (optional) module which owns it.  Needs preempt disabled or module_mutex.
301  */
find_symbol(struct find_symbol_arg * fsa)302 bool find_symbol(struct find_symbol_arg *fsa)
303 {
304 	static const struct symsearch arr[] = {
305 		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
306 		  NOT_GPL_ONLY },
307 		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
308 		  __start___kcrctab_gpl,
309 		  GPL_ONLY },
310 	};
311 	struct module *mod;
312 	unsigned int i;
313 
314 	module_assert_mutex_or_preempt();
315 
316 	for (i = 0; i < ARRAY_SIZE(arr); i++)
317 		if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
318 			return true;
319 
320 	list_for_each_entry_rcu(mod, &modules, list,
321 				lockdep_is_held(&module_mutex)) {
322 		struct symsearch arr[] = {
323 			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
324 			  NOT_GPL_ONLY },
325 			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
326 			  mod->gpl_crcs,
327 			  GPL_ONLY },
328 		};
329 
330 		if (mod->state == MODULE_STATE_UNFORMED)
331 			continue;
332 
333 		for (i = 0; i < ARRAY_SIZE(arr); i++)
334 			if (find_exported_symbol_in_section(&arr[i], mod, fsa))
335 				return true;
336 	}
337 
338 	pr_debug("Failed to find symbol %s\n", fsa->name);
339 	return false;
340 }
341 
342 /*
343  * Search for module by name: must hold module_mutex (or preempt disabled
344  * for read-only access).
345  */
find_module_all(const char * name,size_t len,bool even_unformed)346 struct module *find_module_all(const char *name, size_t len,
347 			       bool even_unformed)
348 {
349 	struct module *mod;
350 
351 	module_assert_mutex_or_preempt();
352 
353 	list_for_each_entry_rcu(mod, &modules, list,
354 				lockdep_is_held(&module_mutex)) {
355 		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
356 			continue;
357 		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
358 			return mod;
359 	}
360 	return NULL;
361 }
362 
find_module(const char * name)363 struct module *find_module(const char *name)
364 {
365 	return find_module_all(name, strlen(name), false);
366 }
367 
368 #ifdef CONFIG_SMP
369 
mod_percpu(struct module * mod)370 static inline void __percpu *mod_percpu(struct module *mod)
371 {
372 	return mod->percpu;
373 }
374 
percpu_modalloc(struct module * mod,struct load_info * info)375 static int percpu_modalloc(struct module *mod, struct load_info *info)
376 {
377 	Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
378 	unsigned long align = pcpusec->sh_addralign;
379 
380 	if (!pcpusec->sh_size)
381 		return 0;
382 
383 	if (align > PAGE_SIZE) {
384 		pr_warn("%s: per-cpu alignment %li > %li\n",
385 			mod->name, align, PAGE_SIZE);
386 		align = PAGE_SIZE;
387 	}
388 
389 	mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
390 	if (!mod->percpu) {
391 		pr_warn("%s: Could not allocate %lu bytes percpu data\n",
392 			mod->name, (unsigned long)pcpusec->sh_size);
393 		return -ENOMEM;
394 	}
395 	mod->percpu_size = pcpusec->sh_size;
396 	return 0;
397 }
398 
percpu_modfree(struct module * mod)399 static void percpu_modfree(struct module *mod)
400 {
401 	free_percpu(mod->percpu);
402 }
403 
find_pcpusec(struct load_info * info)404 static unsigned int find_pcpusec(struct load_info *info)
405 {
406 	return find_sec(info, ".data..percpu");
407 }
408 
percpu_modcopy(struct module * mod,const void * from,unsigned long size)409 static void percpu_modcopy(struct module *mod,
410 			   const void *from, unsigned long size)
411 {
412 	int cpu;
413 
414 	for_each_possible_cpu(cpu)
415 		memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
416 }
417 
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)418 bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
419 {
420 	struct module *mod;
421 	unsigned int cpu;
422 
423 	preempt_disable();
424 
425 	list_for_each_entry_rcu(mod, &modules, list) {
426 		if (mod->state == MODULE_STATE_UNFORMED)
427 			continue;
428 		if (!mod->percpu_size)
429 			continue;
430 		for_each_possible_cpu(cpu) {
431 			void *start = per_cpu_ptr(mod->percpu, cpu);
432 			void *va = (void *)addr;
433 
434 			if (va >= start && va < start + mod->percpu_size) {
435 				if (can_addr) {
436 					*can_addr = (unsigned long) (va - start);
437 					*can_addr += (unsigned long)
438 						per_cpu_ptr(mod->percpu,
439 							    get_boot_cpu_id());
440 				}
441 				preempt_enable();
442 				return true;
443 			}
444 		}
445 	}
446 
447 	preempt_enable();
448 	return false;
449 }
450 
451 /**
452  * is_module_percpu_address() - test whether address is from module static percpu
453  * @addr: address to test
454  *
455  * Test whether @addr belongs to module static percpu area.
456  *
457  * Return: %true if @addr is from module static percpu area
458  */
is_module_percpu_address(unsigned long addr)459 bool is_module_percpu_address(unsigned long addr)
460 {
461 	return __is_module_percpu_address(addr, NULL);
462 }
463 
464 #else /* ... !CONFIG_SMP */
465 
mod_percpu(struct module * mod)466 static inline void __percpu *mod_percpu(struct module *mod)
467 {
468 	return NULL;
469 }
percpu_modalloc(struct module * mod,struct load_info * info)470 static int percpu_modalloc(struct module *mod, struct load_info *info)
471 {
472 	/* UP modules shouldn't have this section: ENOMEM isn't quite right */
473 	if (info->sechdrs[info->index.pcpu].sh_size != 0)
474 		return -ENOMEM;
475 	return 0;
476 }
percpu_modfree(struct module * mod)477 static inline void percpu_modfree(struct module *mod)
478 {
479 }
find_pcpusec(struct load_info * info)480 static unsigned int find_pcpusec(struct load_info *info)
481 {
482 	return 0;
483 }
percpu_modcopy(struct module * mod,const void * from,unsigned long size)484 static inline void percpu_modcopy(struct module *mod,
485 				  const void *from, unsigned long size)
486 {
487 	/* pcpusec should be 0, and size of that section should be 0. */
488 	BUG_ON(size != 0);
489 }
is_module_percpu_address(unsigned long addr)490 bool is_module_percpu_address(unsigned long addr)
491 {
492 	return false;
493 }
494 
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)495 bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
496 {
497 	return false;
498 }
499 
500 #endif /* CONFIG_SMP */
501 
502 #define MODINFO_ATTR(field)	\
503 static void setup_modinfo_##field(struct module *mod, const char *s)  \
504 {                                                                     \
505 	mod->field = kstrdup(s, GFP_KERNEL);                          \
506 }                                                                     \
507 static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
508 			struct module_kobject *mk, char *buffer)      \
509 {                                                                     \
510 	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
511 }                                                                     \
512 static int modinfo_##field##_exists(struct module *mod)               \
513 {                                                                     \
514 	return mod->field != NULL;                                    \
515 }                                                                     \
516 static void free_modinfo_##field(struct module *mod)                  \
517 {                                                                     \
518 	kfree(mod->field);                                            \
519 	mod->field = NULL;                                            \
520 }                                                                     \
521 static struct module_attribute modinfo_##field = {                    \
522 	.attr = { .name = __stringify(field), .mode = 0444 },         \
523 	.show = show_modinfo_##field,                                 \
524 	.setup = setup_modinfo_##field,                               \
525 	.test = modinfo_##field##_exists,                             \
526 	.free = free_modinfo_##field,                                 \
527 };
528 
529 MODINFO_ATTR(version);
530 MODINFO_ATTR(srcversion);
531 
532 static struct {
533 	char name[MODULE_NAME_LEN + 1];
534 	char taints[MODULE_FLAGS_BUF_SIZE];
535 } last_unloaded_module;
536 
537 #ifdef CONFIG_MODULE_UNLOAD
538 
539 EXPORT_TRACEPOINT_SYMBOL(module_get);
540 
541 /* MODULE_REF_BASE is the base reference count by kmodule loader. */
542 #define MODULE_REF_BASE	1
543 
544 /* Init the unload section of the module. */
module_unload_init(struct module * mod)545 static int module_unload_init(struct module *mod)
546 {
547 	/*
548 	 * Initialize reference counter to MODULE_REF_BASE.
549 	 * refcnt == 0 means module is going.
550 	 */
551 	atomic_set(&mod->refcnt, MODULE_REF_BASE);
552 
553 	INIT_LIST_HEAD(&mod->source_list);
554 	INIT_LIST_HEAD(&mod->target_list);
555 
556 	/* Hold reference count during initialization. */
557 	atomic_inc(&mod->refcnt);
558 
559 	return 0;
560 }
561 
562 /* Does a already use b? */
already_uses(struct module * a,struct module * b)563 static int already_uses(struct module *a, struct module *b)
564 {
565 	struct module_use *use;
566 
567 	list_for_each_entry(use, &b->source_list, source_list) {
568 		if (use->source == a)
569 			return 1;
570 	}
571 	pr_debug("%s does not use %s!\n", a->name, b->name);
572 	return 0;
573 }
574 
575 /*
576  * Module a uses b
577  *  - we add 'a' as a "source", 'b' as a "target" of module use
578  *  - the module_use is added to the list of 'b' sources (so
579  *    'b' can walk the list to see who sourced them), and of 'a'
580  *    targets (so 'a' can see what modules it targets).
581  */
add_module_usage(struct module * a,struct module * b)582 static int add_module_usage(struct module *a, struct module *b)
583 {
584 	struct module_use *use;
585 
586 	pr_debug("Allocating new usage for %s.\n", a->name);
587 	use = kmalloc(sizeof(*use), GFP_ATOMIC);
588 	if (!use)
589 		return -ENOMEM;
590 
591 	use->source = a;
592 	use->target = b;
593 	list_add(&use->source_list, &b->source_list);
594 	list_add(&use->target_list, &a->target_list);
595 	return 0;
596 }
597 
598 /* Module a uses b: caller needs module_mutex() */
ref_module(struct module * a,struct module * b)599 static int ref_module(struct module *a, struct module *b)
600 {
601 	int err;
602 
603 	if (b == NULL || already_uses(a, b))
604 		return 0;
605 
606 	/* If module isn't available, we fail. */
607 	err = strong_try_module_get(b);
608 	if (err)
609 		return err;
610 
611 	err = add_module_usage(a, b);
612 	if (err) {
613 		module_put(b);
614 		return err;
615 	}
616 	return 0;
617 }
618 
619 /* Clear the unload stuff of the module. */
module_unload_free(struct module * mod)620 static void module_unload_free(struct module *mod)
621 {
622 	struct module_use *use, *tmp;
623 
624 	mutex_lock(&module_mutex);
625 	list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
626 		struct module *i = use->target;
627 		pr_debug("%s unusing %s\n", mod->name, i->name);
628 		module_put(i);
629 		list_del(&use->source_list);
630 		list_del(&use->target_list);
631 		kfree(use);
632 	}
633 	mutex_unlock(&module_mutex);
634 }
635 
636 #ifdef CONFIG_MODULE_FORCE_UNLOAD
try_force_unload(unsigned int flags)637 static inline int try_force_unload(unsigned int flags)
638 {
639 	int ret = (flags & O_TRUNC);
640 	if (ret)
641 		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
642 	return ret;
643 }
644 #else
try_force_unload(unsigned int flags)645 static inline int try_force_unload(unsigned int flags)
646 {
647 	return 0;
648 }
649 #endif /* CONFIG_MODULE_FORCE_UNLOAD */
650 
651 /* Try to release refcount of module, 0 means success. */
try_release_module_ref(struct module * mod)652 static int try_release_module_ref(struct module *mod)
653 {
654 	int ret;
655 
656 	/* Try to decrement refcnt which we set at loading */
657 	ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt);
658 	BUG_ON(ret < 0);
659 	if (ret)
660 		/* Someone can put this right now, recover with checking */
661 		ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0);
662 
663 	return ret;
664 }
665 
try_stop_module(struct module * mod,int flags,int * forced)666 static int try_stop_module(struct module *mod, int flags, int *forced)
667 {
668 	/* If it's not unused, quit unless we're forcing. */
669 	if (try_release_module_ref(mod) != 0) {
670 		*forced = try_force_unload(flags);
671 		if (!(*forced))
672 			return -EWOULDBLOCK;
673 	}
674 
675 	/* Mark it as dying. */
676 	mod->state = MODULE_STATE_GOING;
677 
678 	return 0;
679 }
680 
681 /**
682  * module_refcount() - return the refcount or -1 if unloading
683  * @mod:	the module we're checking
684  *
685  * Return:
686  *	-1 if the module is in the process of unloading
687  *	otherwise the number of references in the kernel to the module
688  */
module_refcount(struct module * mod)689 int module_refcount(struct module *mod)
690 {
691 	return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
692 }
693 EXPORT_SYMBOL(module_refcount);
694 
695 /* This exists whether we can unload or not */
696 static void free_module(struct module *mod);
697 
SYSCALL_DEFINE2(delete_module,const char __user *,name_user,unsigned int,flags)698 SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
699 		unsigned int, flags)
700 {
701 	struct module *mod;
702 	char name[MODULE_NAME_LEN];
703 	char buf[MODULE_FLAGS_BUF_SIZE];
704 	int ret, forced = 0;
705 
706 	if (!capable(CAP_SYS_MODULE) || modules_disabled)
707 		return -EPERM;
708 
709 	if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
710 		return -EFAULT;
711 	name[MODULE_NAME_LEN-1] = '\0';
712 
713 	audit_log_kern_module(name);
714 
715 	if (mutex_lock_interruptible(&module_mutex) != 0)
716 		return -EINTR;
717 
718 	mod = find_module(name);
719 	if (!mod) {
720 		ret = -ENOENT;
721 		goto out;
722 	}
723 
724 	if (!list_empty(&mod->source_list)) {
725 		/* Other modules depend on us: get rid of them first. */
726 		ret = -EWOULDBLOCK;
727 		goto out;
728 	}
729 
730 	/* Doing init or already dying? */
731 	if (mod->state != MODULE_STATE_LIVE) {
732 		/* FIXME: if (force), slam module count damn the torpedoes */
733 		pr_debug("%s already dying\n", mod->name);
734 		ret = -EBUSY;
735 		goto out;
736 	}
737 
738 	/* If it has an init func, it must have an exit func to unload */
739 	if (mod->init && !mod->exit) {
740 		forced = try_force_unload(flags);
741 		if (!forced) {
742 			/* This module can't be removed */
743 			ret = -EBUSY;
744 			goto out;
745 		}
746 	}
747 
748 	ret = try_stop_module(mod, flags, &forced);
749 	if (ret != 0)
750 		goto out;
751 
752 	mutex_unlock(&module_mutex);
753 	/* Final destruction now no one is using it. */
754 	if (mod->exit != NULL)
755 		mod->exit();
756 	blocking_notifier_call_chain(&module_notify_list,
757 				     MODULE_STATE_GOING, mod);
758 	klp_module_going(mod);
759 	ftrace_release_mod(mod);
760 
761 	async_synchronize_full();
762 
763 	/* Store the name and taints of the last unloaded module for diagnostic purposes */
764 	strscpy(last_unloaded_module.name, mod->name, sizeof(last_unloaded_module.name));
765 	strscpy(last_unloaded_module.taints, module_flags(mod, buf, false), sizeof(last_unloaded_module.taints));
766 
767 	free_module(mod);
768 	/* someone could wait for the module in add_unformed_module() */
769 	wake_up_all(&module_wq);
770 	return 0;
771 out:
772 	mutex_unlock(&module_mutex);
773 	return ret;
774 }
775 
__symbol_put(const char * symbol)776 void __symbol_put(const char *symbol)
777 {
778 	struct find_symbol_arg fsa = {
779 		.name	= symbol,
780 		.gplok	= true,
781 	};
782 
783 	preempt_disable();
784 	BUG_ON(!find_symbol(&fsa));
785 	module_put(fsa.owner);
786 	preempt_enable();
787 }
788 EXPORT_SYMBOL(__symbol_put);
789 
790 /* Note this assumes addr is a function, which it currently always is. */
symbol_put_addr(void * addr)791 void symbol_put_addr(void *addr)
792 {
793 	struct module *modaddr;
794 	unsigned long a = (unsigned long)dereference_function_descriptor(addr);
795 
796 	if (core_kernel_text(a))
797 		return;
798 
799 	/*
800 	 * Even though we hold a reference on the module; we still need to
801 	 * disable preemption in order to safely traverse the data structure.
802 	 */
803 	preempt_disable();
804 	modaddr = __module_text_address(a);
805 	BUG_ON(!modaddr);
806 	module_put(modaddr);
807 	preempt_enable();
808 }
809 EXPORT_SYMBOL_GPL(symbol_put_addr);
810 
show_refcnt(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)811 static ssize_t show_refcnt(struct module_attribute *mattr,
812 			   struct module_kobject *mk, char *buffer)
813 {
814 	return sprintf(buffer, "%i\n", module_refcount(mk->mod));
815 }
816 
817 static struct module_attribute modinfo_refcnt =
818 	__ATTR(refcnt, 0444, show_refcnt, NULL);
819 
__module_get(struct module * module)820 void __module_get(struct module *module)
821 {
822 	if (module) {
823 		atomic_inc(&module->refcnt);
824 		trace_module_get(module, _RET_IP_);
825 	}
826 }
827 EXPORT_SYMBOL(__module_get);
828 
try_module_get(struct module * module)829 bool try_module_get(struct module *module)
830 {
831 	bool ret = true;
832 
833 	if (module) {
834 		/* Note: here, we can fail to get a reference */
835 		if (likely(module_is_live(module) &&
836 			   atomic_inc_not_zero(&module->refcnt) != 0))
837 			trace_module_get(module, _RET_IP_);
838 		else
839 			ret = false;
840 	}
841 	return ret;
842 }
843 EXPORT_SYMBOL(try_module_get);
844 
module_put(struct module * module)845 void module_put(struct module *module)
846 {
847 	int ret;
848 
849 	if (module) {
850 		ret = atomic_dec_if_positive(&module->refcnt);
851 		WARN_ON(ret < 0);	/* Failed to put refcount */
852 		trace_module_put(module, _RET_IP_);
853 	}
854 }
855 EXPORT_SYMBOL(module_put);
856 
857 #else /* !CONFIG_MODULE_UNLOAD */
module_unload_free(struct module * mod)858 static inline void module_unload_free(struct module *mod)
859 {
860 }
861 
ref_module(struct module * a,struct module * b)862 static int ref_module(struct module *a, struct module *b)
863 {
864 	return strong_try_module_get(b);
865 }
866 
module_unload_init(struct module * mod)867 static inline int module_unload_init(struct module *mod)
868 {
869 	return 0;
870 }
871 #endif /* CONFIG_MODULE_UNLOAD */
872 
module_flags_taint(unsigned long taints,char * buf)873 size_t module_flags_taint(unsigned long taints, char *buf)
874 {
875 	size_t l = 0;
876 	int i;
877 
878 	for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
879 		if (taint_flags[i].module && test_bit(i, &taints))
880 			buf[l++] = taint_flags[i].c_true;
881 	}
882 
883 	return l;
884 }
885 
show_initstate(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)886 static ssize_t show_initstate(struct module_attribute *mattr,
887 			      struct module_kobject *mk, char *buffer)
888 {
889 	const char *state = "unknown";
890 
891 	switch (mk->mod->state) {
892 	case MODULE_STATE_LIVE:
893 		state = "live";
894 		break;
895 	case MODULE_STATE_COMING:
896 		state = "coming";
897 		break;
898 	case MODULE_STATE_GOING:
899 		state = "going";
900 		break;
901 	default:
902 		BUG();
903 	}
904 	return sprintf(buffer, "%s\n", state);
905 }
906 
907 static struct module_attribute modinfo_initstate =
908 	__ATTR(initstate, 0444, show_initstate, NULL);
909 
store_uevent(struct module_attribute * mattr,struct module_kobject * mk,const char * buffer,size_t count)910 static ssize_t store_uevent(struct module_attribute *mattr,
911 			    struct module_kobject *mk,
912 			    const char *buffer, size_t count)
913 {
914 	int rc;
915 
916 	rc = kobject_synth_uevent(&mk->kobj, buffer, count);
917 	return rc ? rc : count;
918 }
919 
920 struct module_attribute module_uevent =
921 	__ATTR(uevent, 0200, NULL, store_uevent);
922 
show_coresize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)923 static ssize_t show_coresize(struct module_attribute *mattr,
924 			     struct module_kobject *mk, char *buffer)
925 {
926 	unsigned int size = mk->mod->mem[MOD_TEXT].size;
927 
928 	if (!IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC)) {
929 		for_class_mod_mem_type(type, core_data)
930 			size += mk->mod->mem[type].size;
931 	}
932 	return sprintf(buffer, "%u\n", size);
933 }
934 
935 static struct module_attribute modinfo_coresize =
936 	__ATTR(coresize, 0444, show_coresize, NULL);
937 
938 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
show_datasize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)939 static ssize_t show_datasize(struct module_attribute *mattr,
940 			     struct module_kobject *mk, char *buffer)
941 {
942 	unsigned int size = 0;
943 
944 	for_class_mod_mem_type(type, core_data)
945 		size += mk->mod->mem[type].size;
946 	return sprintf(buffer, "%u\n", size);
947 }
948 
949 static struct module_attribute modinfo_datasize =
950 	__ATTR(datasize, 0444, show_datasize, NULL);
951 #endif
952 
show_initsize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)953 static ssize_t show_initsize(struct module_attribute *mattr,
954 			     struct module_kobject *mk, char *buffer)
955 {
956 	unsigned int size = 0;
957 
958 	for_class_mod_mem_type(type, init)
959 		size += mk->mod->mem[type].size;
960 	return sprintf(buffer, "%u\n", size);
961 }
962 
963 static struct module_attribute modinfo_initsize =
964 	__ATTR(initsize, 0444, show_initsize, NULL);
965 
show_taint(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)966 static ssize_t show_taint(struct module_attribute *mattr,
967 			  struct module_kobject *mk, char *buffer)
968 {
969 	size_t l;
970 
971 	l = module_flags_taint(mk->mod->taints, buffer);
972 	buffer[l++] = '\n';
973 	return l;
974 }
975 
976 static struct module_attribute modinfo_taint =
977 	__ATTR(taint, 0444, show_taint, NULL);
978 
979 struct module_attribute *modinfo_attrs[] = {
980 	&module_uevent,
981 	&modinfo_version,
982 	&modinfo_srcversion,
983 	&modinfo_initstate,
984 	&modinfo_coresize,
985 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
986 	&modinfo_datasize,
987 #endif
988 	&modinfo_initsize,
989 	&modinfo_taint,
990 #ifdef CONFIG_MODULE_UNLOAD
991 	&modinfo_refcnt,
992 #endif
993 	NULL,
994 };
995 
996 size_t modinfo_attrs_count = ARRAY_SIZE(modinfo_attrs);
997 
998 static const char vermagic[] = VERMAGIC_STRING;
999 
try_to_force_load(struct module * mod,const char * reason)1000 int try_to_force_load(struct module *mod, const char *reason)
1001 {
1002 #ifdef CONFIG_MODULE_FORCE_LOAD
1003 	if (!test_taint(TAINT_FORCED_MODULE))
1004 		pr_warn("%s: %s: kernel tainted.\n", mod->name, reason);
1005 	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
1006 	return 0;
1007 #else
1008 	return -ENOEXEC;
1009 #endif
1010 }
1011 
1012 /* Parse tag=value strings from .modinfo section */
module_next_tag_pair(char * string,unsigned long * secsize)1013 char *module_next_tag_pair(char *string, unsigned long *secsize)
1014 {
1015 	/* Skip non-zero chars */
1016 	while (string[0]) {
1017 		string++;
1018 		if ((*secsize)-- <= 1)
1019 			return NULL;
1020 	}
1021 
1022 	/* Skip any zero padding. */
1023 	while (!string[0]) {
1024 		string++;
1025 		if ((*secsize)-- <= 1)
1026 			return NULL;
1027 	}
1028 	return string;
1029 }
1030 
get_next_modinfo(const struct load_info * info,const char * tag,char * prev)1031 static char *get_next_modinfo(const struct load_info *info, const char *tag,
1032 			      char *prev)
1033 {
1034 	char *p;
1035 	unsigned int taglen = strlen(tag);
1036 	Elf_Shdr *infosec = &info->sechdrs[info->index.info];
1037 	unsigned long size = infosec->sh_size;
1038 
1039 	/*
1040 	 * get_modinfo() calls made before rewrite_section_headers()
1041 	 * must use sh_offset, as sh_addr isn't set!
1042 	 */
1043 	char *modinfo = (char *)info->hdr + infosec->sh_offset;
1044 
1045 	if (prev) {
1046 		size -= prev - modinfo;
1047 		modinfo = module_next_tag_pair(prev, &size);
1048 	}
1049 
1050 	for (p = modinfo; p; p = module_next_tag_pair(p, &size)) {
1051 		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
1052 			return p + taglen + 1;
1053 	}
1054 	return NULL;
1055 }
1056 
get_modinfo(const struct load_info * info,const char * tag)1057 static char *get_modinfo(const struct load_info *info, const char *tag)
1058 {
1059 	return get_next_modinfo(info, tag, NULL);
1060 }
1061 
verify_namespace_is_imported(const struct load_info * info,const struct kernel_symbol * sym,struct module * mod)1062 static int verify_namespace_is_imported(const struct load_info *info,
1063 					const struct kernel_symbol *sym,
1064 					struct module *mod)
1065 {
1066 	const char *namespace;
1067 	char *imported_namespace;
1068 
1069 	namespace = kernel_symbol_namespace(sym);
1070 	if (namespace && namespace[0]) {
1071 		for_each_modinfo_entry(imported_namespace, info, "import_ns") {
1072 			if (strcmp(namespace, imported_namespace) == 0)
1073 				return 0;
1074 		}
1075 #ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1076 		pr_warn(
1077 #else
1078 		pr_err(
1079 #endif
1080 			"%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
1081 			mod->name, kernel_symbol_name(sym), namespace);
1082 #ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1083 		return -EINVAL;
1084 #endif
1085 	}
1086 	return 0;
1087 }
1088 
inherit_taint(struct module * mod,struct module * owner,const char * name)1089 static bool inherit_taint(struct module *mod, struct module *owner, const char *name)
1090 {
1091 	if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
1092 		return true;
1093 
1094 	if (mod->using_gplonly_symbols) {
1095 		pr_err("%s: module using GPL-only symbols uses symbols %s from proprietary module %s.\n",
1096 			mod->name, name, owner->name);
1097 		return false;
1098 	}
1099 
1100 	if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
1101 		pr_warn("%s: module uses symbols %s from proprietary module %s, inheriting taint.\n",
1102 			mod->name, name, owner->name);
1103 		set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
1104 	}
1105 	return true;
1106 }
1107 
1108 /* 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[])1109 static const struct kernel_symbol *resolve_symbol(struct module *mod,
1110 						  const struct load_info *info,
1111 						  const char *name,
1112 						  char ownername[])
1113 {
1114 	struct find_symbol_arg fsa = {
1115 		.name	= name,
1116 		.gplok	= !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
1117 		.warn	= true,
1118 	};
1119 	int err;
1120 
1121 	/*
1122 	 * The module_mutex should not be a heavily contended lock;
1123 	 * if we get the occasional sleep here, we'll go an extra iteration
1124 	 * in the wait_event_interruptible(), which is harmless.
1125 	 */
1126 	sched_annotate_sleep();
1127 	mutex_lock(&module_mutex);
1128 	if (!find_symbol(&fsa))
1129 		goto unlock;
1130 
1131 	if (fsa.license == GPL_ONLY)
1132 		mod->using_gplonly_symbols = true;
1133 
1134 	if (!inherit_taint(mod, fsa.owner, name)) {
1135 		fsa.sym = NULL;
1136 		goto getname;
1137 	}
1138 
1139 	if (!check_version(info, name, mod, fsa.crc)) {
1140 		fsa.sym = ERR_PTR(-EINVAL);
1141 		goto getname;
1142 	}
1143 
1144 	err = verify_namespace_is_imported(info, fsa.sym, mod);
1145 	if (err) {
1146 		fsa.sym = ERR_PTR(err);
1147 		goto getname;
1148 	}
1149 
1150 	err = ref_module(mod, fsa.owner);
1151 	if (err) {
1152 		fsa.sym = ERR_PTR(err);
1153 		goto getname;
1154 	}
1155 
1156 getname:
1157 	/* We must make copy under the lock if we failed to get ref. */
1158 	strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
1159 unlock:
1160 	mutex_unlock(&module_mutex);
1161 	return fsa.sym;
1162 }
1163 
1164 static const struct kernel_symbol *
resolve_symbol_wait(struct module * mod,const struct load_info * info,const char * name)1165 resolve_symbol_wait(struct module *mod,
1166 		    const struct load_info *info,
1167 		    const char *name)
1168 {
1169 	const struct kernel_symbol *ksym;
1170 	char owner[MODULE_NAME_LEN];
1171 
1172 	if (wait_event_interruptible_timeout(module_wq,
1173 			!IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
1174 			|| PTR_ERR(ksym) != -EBUSY,
1175 					     30 * HZ) <= 0) {
1176 		pr_warn("%s: gave up waiting for init of module %s.\n",
1177 			mod->name, owner);
1178 	}
1179 	return ksym;
1180 }
1181 
module_memfree(void * module_region)1182 void __weak module_memfree(void *module_region)
1183 {
1184 	/*
1185 	 * This memory may be RO, and freeing RO memory in an interrupt is not
1186 	 * supported by vmalloc.
1187 	 */
1188 	WARN_ON(in_interrupt());
1189 	vfree(module_region);
1190 }
1191 
module_arch_cleanup(struct module * mod)1192 void __weak module_arch_cleanup(struct module *mod)
1193 {
1194 }
1195 
module_arch_freeing_init(struct module * mod)1196 void __weak module_arch_freeing_init(struct module *mod)
1197 {
1198 }
1199 
mod_mem_use_vmalloc(enum mod_mem_type type)1200 static bool mod_mem_use_vmalloc(enum mod_mem_type type)
1201 {
1202 	return IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC) &&
1203 		mod_mem_type_is_core_data(type);
1204 }
1205 
module_memory_alloc(unsigned int size,enum mod_mem_type type)1206 static void *module_memory_alloc(unsigned int size, enum mod_mem_type type)
1207 {
1208 	if (mod_mem_use_vmalloc(type))
1209 		return vzalloc(size);
1210 	return module_alloc(size);
1211 }
1212 
module_memory_free(void * ptr,enum mod_mem_type type)1213 static void module_memory_free(void *ptr, enum mod_mem_type type)
1214 {
1215 	if (mod_mem_use_vmalloc(type))
1216 		vfree(ptr);
1217 	else
1218 		module_memfree(ptr);
1219 }
1220 
free_mod_mem(struct module * mod)1221 static void free_mod_mem(struct module *mod)
1222 {
1223 	for_each_mod_mem_type(type) {
1224 		struct module_memory *mod_mem = &mod->mem[type];
1225 
1226 		if (type == MOD_DATA)
1227 			continue;
1228 
1229 		/* Free lock-classes; relies on the preceding sync_rcu(). */
1230 		lockdep_free_key_range(mod_mem->base, mod_mem->size);
1231 		if (mod_mem->size)
1232 			module_memory_free(mod_mem->base, type);
1233 	}
1234 
1235 	/* MOD_DATA hosts mod, so free it at last */
1236 	lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
1237 	module_memory_free(mod->mem[MOD_DATA].base, MOD_DATA);
1238 }
1239 
1240 /* Free a module, remove from lists, etc. */
free_module(struct module * mod)1241 static void free_module(struct module *mod)
1242 {
1243 	trace_module_free(mod);
1244 
1245 	mod_sysfs_teardown(mod);
1246 
1247 	/*
1248 	 * We leave it in list to prevent duplicate loads, but make sure
1249 	 * that noone uses it while it's being deconstructed.
1250 	 */
1251 	mutex_lock(&module_mutex);
1252 	mod->state = MODULE_STATE_UNFORMED;
1253 	mutex_unlock(&module_mutex);
1254 
1255 	/* Arch-specific cleanup. */
1256 	module_arch_cleanup(mod);
1257 
1258 	/* Module unload stuff */
1259 	module_unload_free(mod);
1260 
1261 	/* Free any allocated parameters. */
1262 	destroy_params(mod->kp, mod->num_kp);
1263 
1264 	if (is_livepatch_module(mod))
1265 		free_module_elf(mod);
1266 
1267 	/* Now we can delete it from the lists */
1268 	mutex_lock(&module_mutex);
1269 	/* Unlink carefully: kallsyms could be walking list. */
1270 	list_del_rcu(&mod->list);
1271 	mod_tree_remove(mod);
1272 	/* Remove this module from bug list, this uses list_del_rcu */
1273 	module_bug_cleanup(mod);
1274 	/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
1275 	synchronize_rcu();
1276 	if (try_add_tainted_module(mod))
1277 		pr_err("%s: adding tainted module to the unloaded tainted modules list failed.\n",
1278 		       mod->name);
1279 	mutex_unlock(&module_mutex);
1280 
1281 	/* This may be empty, but that's OK */
1282 	module_arch_freeing_init(mod);
1283 	kfree(mod->args);
1284 	percpu_modfree(mod);
1285 
1286 	free_mod_mem(mod);
1287 }
1288 
__symbol_get(const char * symbol)1289 void *__symbol_get(const char *symbol)
1290 {
1291 	struct find_symbol_arg fsa = {
1292 		.name	= symbol,
1293 		.gplok	= true,
1294 		.warn	= true,
1295 	};
1296 
1297 	preempt_disable();
1298 	if (!find_symbol(&fsa))
1299 		goto fail;
1300 	if (fsa.license != GPL_ONLY) {
1301 		pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n",
1302 			symbol);
1303 		goto fail;
1304 	}
1305 	if (strong_try_module_get(fsa.owner))
1306 		goto fail;
1307 	preempt_enable();
1308 	return (void *)kernel_symbol_value(fsa.sym);
1309 fail:
1310 	preempt_enable();
1311 	return NULL;
1312 }
1313 EXPORT_SYMBOL_GPL(__symbol_get);
1314 
1315 /*
1316  * Ensure that an exported symbol [global namespace] does not already exist
1317  * in the kernel or in some other module's exported symbol table.
1318  *
1319  * You must hold the module_mutex.
1320  */
verify_exported_symbols(struct module * mod)1321 static int verify_exported_symbols(struct module *mod)
1322 {
1323 	unsigned int i;
1324 	const struct kernel_symbol *s;
1325 	struct {
1326 		const struct kernel_symbol *sym;
1327 		unsigned int num;
1328 	} arr[] = {
1329 		{ mod->syms, mod->num_syms },
1330 		{ mod->gpl_syms, mod->num_gpl_syms },
1331 	};
1332 
1333 	for (i = 0; i < ARRAY_SIZE(arr); i++) {
1334 		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
1335 			struct find_symbol_arg fsa = {
1336 				.name	= kernel_symbol_name(s),
1337 				.gplok	= true,
1338 			};
1339 			if (find_symbol(&fsa)) {
1340 				pr_err("%s: exports duplicate symbol %s"
1341 				       " (owned by %s)\n",
1342 				       mod->name, kernel_symbol_name(s),
1343 				       module_name(fsa.owner));
1344 				return -ENOEXEC;
1345 			}
1346 		}
1347 	}
1348 	return 0;
1349 }
1350 
ignore_undef_symbol(Elf_Half emachine,const char * name)1351 static bool ignore_undef_symbol(Elf_Half emachine, const char *name)
1352 {
1353 	/*
1354 	 * On x86, PIC code and Clang non-PIC code may have call foo@PLT. GNU as
1355 	 * before 2.37 produces an unreferenced _GLOBAL_OFFSET_TABLE_ on x86-64.
1356 	 * i386 has a similar problem but may not deserve a fix.
1357 	 *
1358 	 * If we ever have to ignore many symbols, consider refactoring the code to
1359 	 * only warn if referenced by a relocation.
1360 	 */
1361 	if (emachine == EM_386 || emachine == EM_X86_64)
1362 		return !strcmp(name, "_GLOBAL_OFFSET_TABLE_");
1363 	return false;
1364 }
1365 
1366 /* Change all symbols so that st_value encodes the pointer directly. */
simplify_symbols(struct module * mod,const struct load_info * info)1367 static int simplify_symbols(struct module *mod, const struct load_info *info)
1368 {
1369 	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
1370 	Elf_Sym *sym = (void *)symsec->sh_addr;
1371 	unsigned long secbase;
1372 	unsigned int i;
1373 	int ret = 0;
1374 	const struct kernel_symbol *ksym;
1375 
1376 	for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
1377 		const char *name = info->strtab + sym[i].st_name;
1378 
1379 		switch (sym[i].st_shndx) {
1380 		case SHN_COMMON:
1381 			/* Ignore common symbols */
1382 			if (!strncmp(name, "__gnu_lto", 9))
1383 				break;
1384 
1385 			/*
1386 			 * We compiled with -fno-common.  These are not
1387 			 * supposed to happen.
1388 			 */
1389 			pr_debug("Common symbol: %s\n", name);
1390 			pr_warn("%s: please compile with -fno-common\n",
1391 			       mod->name);
1392 			ret = -ENOEXEC;
1393 			break;
1394 
1395 		case SHN_ABS:
1396 			/* Don't need to do anything */
1397 			pr_debug("Absolute symbol: 0x%08lx %s\n",
1398 				 (long)sym[i].st_value, name);
1399 			break;
1400 
1401 		case SHN_LIVEPATCH:
1402 			/* Livepatch symbols are resolved by livepatch */
1403 			break;
1404 
1405 		case SHN_UNDEF:
1406 			ksym = resolve_symbol_wait(mod, info, name);
1407 			/* Ok if resolved.  */
1408 			if (ksym && !IS_ERR(ksym)) {
1409 				sym[i].st_value = kernel_symbol_value(ksym);
1410 				break;
1411 			}
1412 
1413 			/* Ok if weak or ignored.  */
1414 			if (!ksym &&
1415 			    (ELF_ST_BIND(sym[i].st_info) == STB_WEAK ||
1416 			     ignore_undef_symbol(info->hdr->e_machine, name)))
1417 				break;
1418 
1419 			ret = PTR_ERR(ksym) ?: -ENOENT;
1420 			pr_warn("%s: Unknown symbol %s (err %d)\n",
1421 				mod->name, name, ret);
1422 			break;
1423 
1424 		default:
1425 			/* Divert to percpu allocation if a percpu var. */
1426 			if (sym[i].st_shndx == info->index.pcpu)
1427 				secbase = (unsigned long)mod_percpu(mod);
1428 			else
1429 				secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
1430 			sym[i].st_value += secbase;
1431 			break;
1432 		}
1433 	}
1434 
1435 	return ret;
1436 }
1437 
apply_relocations(struct module * mod,const struct load_info * info)1438 static int apply_relocations(struct module *mod, const struct load_info *info)
1439 {
1440 	unsigned int i;
1441 	int err = 0;
1442 
1443 	/* Now do relocations. */
1444 	for (i = 1; i < info->hdr->e_shnum; i++) {
1445 		unsigned int infosec = info->sechdrs[i].sh_info;
1446 
1447 		/* Not a valid relocation section? */
1448 		if (infosec >= info->hdr->e_shnum)
1449 			continue;
1450 
1451 		/* Don't bother with non-allocated sections */
1452 		if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
1453 			continue;
1454 
1455 		if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
1456 			err = klp_apply_section_relocs(mod, info->sechdrs,
1457 						       info->secstrings,
1458 						       info->strtab,
1459 						       info->index.sym, i,
1460 						       NULL);
1461 		else if (info->sechdrs[i].sh_type == SHT_REL)
1462 			err = apply_relocate(info->sechdrs, info->strtab,
1463 					     info->index.sym, i, mod);
1464 		else if (info->sechdrs[i].sh_type == SHT_RELA)
1465 			err = apply_relocate_add(info->sechdrs, info->strtab,
1466 						 info->index.sym, i, mod);
1467 		if (err < 0)
1468 			break;
1469 	}
1470 	return err;
1471 }
1472 
1473 /* Additional bytes needed by arch in front of individual sections */
arch_mod_section_prepend(struct module * mod,unsigned int section)1474 unsigned int __weak arch_mod_section_prepend(struct module *mod,
1475 					     unsigned int section)
1476 {
1477 	/* default implementation just returns zero */
1478 	return 0;
1479 }
1480 
module_get_offset_and_type(struct module * mod,enum mod_mem_type type,Elf_Shdr * sechdr,unsigned int section)1481 long module_get_offset_and_type(struct module *mod, enum mod_mem_type type,
1482 				Elf_Shdr *sechdr, unsigned int section)
1483 {
1484 	long offset;
1485 	long mask = ((unsigned long)(type) & SH_ENTSIZE_TYPE_MASK) << SH_ENTSIZE_TYPE_SHIFT;
1486 
1487 	mod->mem[type].size += arch_mod_section_prepend(mod, section);
1488 	offset = ALIGN(mod->mem[type].size, sechdr->sh_addralign ?: 1);
1489 	mod->mem[type].size = offset + sechdr->sh_size;
1490 
1491 	WARN_ON_ONCE(offset & mask);
1492 	return offset | mask;
1493 }
1494 
module_init_layout_section(const char * sname)1495 bool module_init_layout_section(const char *sname)
1496 {
1497 #ifndef CONFIG_MODULE_UNLOAD
1498 	if (module_exit_section(sname))
1499 		return true;
1500 #endif
1501 	return module_init_section(sname);
1502 }
1503 
__layout_sections(struct module * mod,struct load_info * info,bool is_init)1504 static void __layout_sections(struct module *mod, struct load_info *info, bool is_init)
1505 {
1506 	unsigned int m, i;
1507 
1508 	static const unsigned long masks[][2] = {
1509 		/*
1510 		 * NOTE: all executable code must be the first section
1511 		 * in this array; otherwise modify the text_size
1512 		 * finder in the two loops below
1513 		 */
1514 		{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
1515 		{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
1516 		{ SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
1517 		{ SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
1518 		{ ARCH_SHF_SMALL | SHF_ALLOC, 0 }
1519 	};
1520 	static const int core_m_to_mem_type[] = {
1521 		MOD_TEXT,
1522 		MOD_RODATA,
1523 		MOD_RO_AFTER_INIT,
1524 		MOD_DATA,
1525 		MOD_DATA,
1526 	};
1527 	static const int init_m_to_mem_type[] = {
1528 		MOD_INIT_TEXT,
1529 		MOD_INIT_RODATA,
1530 		MOD_INVALID,
1531 		MOD_INIT_DATA,
1532 		MOD_INIT_DATA,
1533 	};
1534 
1535 	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
1536 		enum mod_mem_type type = is_init ? init_m_to_mem_type[m] : core_m_to_mem_type[m];
1537 
1538 		for (i = 0; i < info->hdr->e_shnum; ++i) {
1539 			Elf_Shdr *s = &info->sechdrs[i];
1540 			const char *sname = info->secstrings + s->sh_name;
1541 
1542 			if ((s->sh_flags & masks[m][0]) != masks[m][0]
1543 			    || (s->sh_flags & masks[m][1])
1544 			    || s->sh_entsize != ~0UL
1545 			    || is_init != module_init_layout_section(sname))
1546 				continue;
1547 
1548 			if (WARN_ON_ONCE(type == MOD_INVALID))
1549 				continue;
1550 
1551 			s->sh_entsize = module_get_offset_and_type(mod, type, s, i);
1552 			pr_debug("\t%s\n", sname);
1553 		}
1554 	}
1555 }
1556 
1557 /*
1558  * Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
1559  * might -- code, read-only data, read-write data, small data.  Tally
1560  * sizes, and place the offsets into sh_entsize fields: high bit means it
1561  * belongs in init.
1562  */
layout_sections(struct module * mod,struct load_info * info)1563 static void layout_sections(struct module *mod, struct load_info *info)
1564 {
1565 	unsigned int i;
1566 
1567 	for (i = 0; i < info->hdr->e_shnum; i++)
1568 		info->sechdrs[i].sh_entsize = ~0UL;
1569 
1570 	pr_debug("Core section allocation order for %s:\n", mod->name);
1571 	__layout_sections(mod, info, false);
1572 
1573 	pr_debug("Init section allocation order for %s:\n", mod->name);
1574 	__layout_sections(mod, info, true);
1575 }
1576 
module_license_taint_check(struct module * mod,const char * license)1577 static void module_license_taint_check(struct module *mod, const char *license)
1578 {
1579 	if (!license)
1580 		license = "unspecified";
1581 
1582 	if (!license_is_gpl_compatible(license)) {
1583 		if (!test_taint(TAINT_PROPRIETARY_MODULE))
1584 			pr_warn("%s: module license '%s' taints kernel.\n",
1585 				mod->name, license);
1586 		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
1587 				 LOCKDEP_NOW_UNRELIABLE);
1588 	}
1589 }
1590 
setup_modinfo(struct module * mod,struct load_info * info)1591 static void setup_modinfo(struct module *mod, struct load_info *info)
1592 {
1593 	struct module_attribute *attr;
1594 	int i;
1595 
1596 	for (i = 0; (attr = modinfo_attrs[i]); i++) {
1597 		if (attr->setup)
1598 			attr->setup(mod, get_modinfo(info, attr->attr.name));
1599 	}
1600 }
1601 
free_modinfo(struct module * mod)1602 static void free_modinfo(struct module *mod)
1603 {
1604 	struct module_attribute *attr;
1605 	int i;
1606 
1607 	for (i = 0; (attr = modinfo_attrs[i]); i++) {
1608 		if (attr->free)
1609 			attr->free(mod);
1610 	}
1611 }
1612 
module_alloc(unsigned long size)1613 void * __weak module_alloc(unsigned long size)
1614 {
1615 	return __vmalloc_node_range(size, 1, VMALLOC_START, VMALLOC_END,
1616 			GFP_KERNEL, PAGE_KERNEL_EXEC, VM_FLUSH_RESET_PERMS,
1617 			NUMA_NO_NODE, __builtin_return_address(0));
1618 }
1619 
module_init_section(const char * name)1620 bool __weak module_init_section(const char *name)
1621 {
1622 	return strstarts(name, ".init");
1623 }
1624 
module_exit_section(const char * name)1625 bool __weak module_exit_section(const char *name)
1626 {
1627 	return strstarts(name, ".exit");
1628 }
1629 
validate_section_offset(struct load_info * info,Elf_Shdr * shdr)1630 static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
1631 {
1632 #if defined(CONFIG_64BIT)
1633 	unsigned long long secend;
1634 #else
1635 	unsigned long secend;
1636 #endif
1637 
1638 	/*
1639 	 * Check for both overflow and offset/size being
1640 	 * too large.
1641 	 */
1642 	secend = shdr->sh_offset + shdr->sh_size;
1643 	if (secend < shdr->sh_offset || secend > info->len)
1644 		return -ENOEXEC;
1645 
1646 	return 0;
1647 }
1648 
1649 /*
1650  * Check userspace passed ELF module against our expectations, and cache
1651  * useful variables for further processing as we go.
1652  *
1653  * This does basic validity checks against section offsets and sizes, the
1654  * section name string table, and the indices used for it (sh_name).
1655  *
1656  * As a last step, since we're already checking the ELF sections we cache
1657  * useful variables which will be used later for our convenience:
1658  *
1659  * 	o pointers to section headers
1660  * 	o cache the modinfo symbol section
1661  * 	o cache the string symbol section
1662  * 	o cache the module section
1663  *
1664  * As a last step we set info->mod to the temporary copy of the module in
1665  * info->hdr. The final one will be allocated in move_module(). Any
1666  * modifications we make to our copy of the module will be carried over
1667  * to the final minted module.
1668  */
elf_validity_cache_copy(struct load_info * info,int flags)1669 static int elf_validity_cache_copy(struct load_info *info, int flags)
1670 {
1671 	unsigned int i;
1672 	Elf_Shdr *shdr, *strhdr;
1673 	int err;
1674 	unsigned int num_mod_secs = 0, mod_idx;
1675 	unsigned int num_info_secs = 0, info_idx;
1676 	unsigned int num_sym_secs = 0, sym_idx;
1677 
1678 	if (info->len < sizeof(*(info->hdr))) {
1679 		pr_err("Invalid ELF header len %lu\n", info->len);
1680 		goto no_exec;
1681 	}
1682 
1683 	if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0) {
1684 		pr_err("Invalid ELF header magic: != %s\n", ELFMAG);
1685 		goto no_exec;
1686 	}
1687 	if (info->hdr->e_type != ET_REL) {
1688 		pr_err("Invalid ELF header type: %u != %u\n",
1689 		       info->hdr->e_type, ET_REL);
1690 		goto no_exec;
1691 	}
1692 	if (!elf_check_arch(info->hdr)) {
1693 		pr_err("Invalid architecture in ELF header: %u\n",
1694 		       info->hdr->e_machine);
1695 		goto no_exec;
1696 	}
1697 	if (!module_elf_check_arch(info->hdr)) {
1698 		pr_err("Invalid module architecture in ELF header: %u\n",
1699 		       info->hdr->e_machine);
1700 		goto no_exec;
1701 	}
1702 	if (info->hdr->e_shentsize != sizeof(Elf_Shdr)) {
1703 		pr_err("Invalid ELF section header size\n");
1704 		goto no_exec;
1705 	}
1706 
1707 	/*
1708 	 * e_shnum is 16 bits, and sizeof(Elf_Shdr) is
1709 	 * known and small. So e_shnum * sizeof(Elf_Shdr)
1710 	 * will not overflow unsigned long on any platform.
1711 	 */
1712 	if (info->hdr->e_shoff >= info->len
1713 	    || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
1714 		info->len - info->hdr->e_shoff)) {
1715 		pr_err("Invalid ELF section header overflow\n");
1716 		goto no_exec;
1717 	}
1718 
1719 	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
1720 
1721 	/*
1722 	 * Verify if the section name table index is valid.
1723 	 */
1724 	if (info->hdr->e_shstrndx == SHN_UNDEF
1725 	    || info->hdr->e_shstrndx >= info->hdr->e_shnum) {
1726 		pr_err("Invalid ELF section name index: %d || e_shstrndx (%d) >= e_shnum (%d)\n",
1727 		       info->hdr->e_shstrndx, info->hdr->e_shstrndx,
1728 		       info->hdr->e_shnum);
1729 		goto no_exec;
1730 	}
1731 
1732 	strhdr = &info->sechdrs[info->hdr->e_shstrndx];
1733 	err = validate_section_offset(info, strhdr);
1734 	if (err < 0) {
1735 		pr_err("Invalid ELF section hdr(type %u)\n", strhdr->sh_type);
1736 		return err;
1737 	}
1738 
1739 	/*
1740 	 * The section name table must be NUL-terminated, as required
1741 	 * by the spec. This makes strcmp and pr_* calls that access
1742 	 * strings in the section safe.
1743 	 */
1744 	info->secstrings = (void *)info->hdr + strhdr->sh_offset;
1745 	if (strhdr->sh_size == 0) {
1746 		pr_err("empty section name table\n");
1747 		goto no_exec;
1748 	}
1749 	if (info->secstrings[strhdr->sh_size - 1] != '\0') {
1750 		pr_err("ELF Spec violation: section name table isn't null terminated\n");
1751 		goto no_exec;
1752 	}
1753 
1754 	/*
1755 	 * The code assumes that section 0 has a length of zero and
1756 	 * an addr of zero, so check for it.
1757 	 */
1758 	if (info->sechdrs[0].sh_type != SHT_NULL
1759 	    || info->sechdrs[0].sh_size != 0
1760 	    || info->sechdrs[0].sh_addr != 0) {
1761 		pr_err("ELF Spec violation: section 0 type(%d)!=SH_NULL or non-zero len or addr\n",
1762 		       info->sechdrs[0].sh_type);
1763 		goto no_exec;
1764 	}
1765 
1766 	for (i = 1; i < info->hdr->e_shnum; i++) {
1767 		shdr = &info->sechdrs[i];
1768 		switch (shdr->sh_type) {
1769 		case SHT_NULL:
1770 		case SHT_NOBITS:
1771 			continue;
1772 		case SHT_SYMTAB:
1773 			if (shdr->sh_link == SHN_UNDEF
1774 			    || shdr->sh_link >= info->hdr->e_shnum) {
1775 				pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n",
1776 				       shdr->sh_link, shdr->sh_link,
1777 				       info->hdr->e_shnum);
1778 				goto no_exec;
1779 			}
1780 			num_sym_secs++;
1781 			sym_idx = i;
1782 			fallthrough;
1783 		default:
1784 			err = validate_section_offset(info, shdr);
1785 			if (err < 0) {
1786 				pr_err("Invalid ELF section in module (section %u type %u)\n",
1787 					i, shdr->sh_type);
1788 				return err;
1789 			}
1790 			if (strcmp(info->secstrings + shdr->sh_name,
1791 				   ".gnu.linkonce.this_module") == 0) {
1792 				num_mod_secs++;
1793 				mod_idx = i;
1794 			} else if (strcmp(info->secstrings + shdr->sh_name,
1795 				   ".modinfo") == 0) {
1796 				num_info_secs++;
1797 				info_idx = i;
1798 			}
1799 
1800 			if (shdr->sh_flags & SHF_ALLOC) {
1801 				if (shdr->sh_name >= strhdr->sh_size) {
1802 					pr_err("Invalid ELF section name in module (section %u type %u)\n",
1803 					       i, shdr->sh_type);
1804 					return -ENOEXEC;
1805 				}
1806 			}
1807 			break;
1808 		}
1809 	}
1810 
1811 	if (num_info_secs > 1) {
1812 		pr_err("Only one .modinfo section must exist.\n");
1813 		goto no_exec;
1814 	} else if (num_info_secs == 1) {
1815 		/* Try to find a name early so we can log errors with a module name */
1816 		info->index.info = info_idx;
1817 		info->name = get_modinfo(info, "name");
1818 	}
1819 
1820 	if (num_sym_secs != 1) {
1821 		pr_warn("%s: module has no symbols (stripped?)\n",
1822 			info->name ?: "(missing .modinfo section or name field)");
1823 		goto no_exec;
1824 	}
1825 
1826 	/* Sets internal symbols and strings. */
1827 	info->index.sym = sym_idx;
1828 	shdr = &info->sechdrs[sym_idx];
1829 	info->index.str = shdr->sh_link;
1830 	info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset;
1831 
1832 	/*
1833 	 * The ".gnu.linkonce.this_module" ELF section is special. It is
1834 	 * what modpost uses to refer to __this_module and let's use rely
1835 	 * on THIS_MODULE to point to &__this_module properly. The kernel's
1836 	 * modpost declares it on each modules's *.mod.c file. If the struct
1837 	 * module of the kernel changes a full kernel rebuild is required.
1838 	 *
1839 	 * We have a few expectaions for this special section, the following
1840 	 * code validates all this for us:
1841 	 *
1842 	 *   o Only one section must exist
1843 	 *   o We expect the kernel to always have to allocate it: SHF_ALLOC
1844 	 *   o The section size must match the kernel's run time's struct module
1845 	 *     size
1846 	 */
1847 	if (num_mod_secs != 1) {
1848 		pr_err("module %s: Only one .gnu.linkonce.this_module section must exist.\n",
1849 		       info->name ?: "(missing .modinfo section or name field)");
1850 		goto no_exec;
1851 	}
1852 
1853 	shdr = &info->sechdrs[mod_idx];
1854 
1855 	/*
1856 	 * This is already implied on the switch above, however let's be
1857 	 * pedantic about it.
1858 	 */
1859 	if (shdr->sh_type == SHT_NOBITS) {
1860 		pr_err("module %s: .gnu.linkonce.this_module section must have a size set\n",
1861 		       info->name ?: "(missing .modinfo section or name field)");
1862 		goto no_exec;
1863 	}
1864 
1865 	if (!(shdr->sh_flags & SHF_ALLOC)) {
1866 		pr_err("module %s: .gnu.linkonce.this_module must occupy memory during process execution\n",
1867 		       info->name ?: "(missing .modinfo section or name field)");
1868 		goto no_exec;
1869 	}
1870 
1871 	if (shdr->sh_size != sizeof(struct module)) {
1872 		pr_err("module %s: .gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n",
1873 		       info->name ?: "(missing .modinfo section or name field)");
1874 		goto no_exec;
1875 	}
1876 
1877 	info->index.mod = mod_idx;
1878 
1879 	/* This is temporary: point mod into copy of data. */
1880 	info->mod = (void *)info->hdr + shdr->sh_offset;
1881 
1882 	/*
1883 	 * If we didn't load the .modinfo 'name' field earlier, fall back to
1884 	 * on-disk struct mod 'name' field.
1885 	 */
1886 	if (!info->name)
1887 		info->name = info->mod->name;
1888 
1889 	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
1890 		info->index.vers = 0; /* Pretend no __versions section! */
1891 	else
1892 		info->index.vers = find_sec(info, "__versions");
1893 
1894 	info->index.pcpu = find_pcpusec(info);
1895 
1896 	return 0;
1897 
1898 no_exec:
1899 	return -ENOEXEC;
1900 }
1901 
1902 #define COPY_CHUNK_SIZE (16*PAGE_SIZE)
1903 
copy_chunked_from_user(void * dst,const void __user * usrc,unsigned long len)1904 static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned long len)
1905 {
1906 	do {
1907 		unsigned long n = min(len, COPY_CHUNK_SIZE);
1908 
1909 		if (copy_from_user(dst, usrc, n) != 0)
1910 			return -EFAULT;
1911 		cond_resched();
1912 		dst += n;
1913 		usrc += n;
1914 		len -= n;
1915 	} while (len);
1916 	return 0;
1917 }
1918 
check_modinfo_livepatch(struct module * mod,struct load_info * info)1919 static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
1920 {
1921 	if (!get_modinfo(info, "livepatch"))
1922 		/* Nothing more to do */
1923 		return 0;
1924 
1925 	if (set_livepatch_module(mod))
1926 		return 0;
1927 
1928 	pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
1929 	       mod->name);
1930 	return -ENOEXEC;
1931 }
1932 
check_modinfo_retpoline(struct module * mod,struct load_info * info)1933 static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
1934 {
1935 	if (retpoline_module_ok(get_modinfo(info, "retpoline")))
1936 		return;
1937 
1938 	pr_warn("%s: loading module not compiled with retpoline compiler.\n",
1939 		mod->name);
1940 }
1941 
1942 /* Sets info->hdr and info->len. */
copy_module_from_user(const void __user * umod,unsigned long len,struct load_info * info)1943 static int copy_module_from_user(const void __user *umod, unsigned long len,
1944 				  struct load_info *info)
1945 {
1946 	int err;
1947 
1948 	info->len = len;
1949 	if (info->len < sizeof(*(info->hdr)))
1950 		return -ENOEXEC;
1951 
1952 	err = security_kernel_load_data(LOADING_MODULE, true);
1953 	if (err)
1954 		return err;
1955 
1956 	/* Suck in entire file: we'll want most of it. */
1957 	info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN);
1958 	if (!info->hdr)
1959 		return -ENOMEM;
1960 
1961 	if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) {
1962 		err = -EFAULT;
1963 		goto out;
1964 	}
1965 
1966 	err = security_kernel_post_load_data((char *)info->hdr, info->len,
1967 					     LOADING_MODULE, "init_module");
1968 out:
1969 	if (err)
1970 		vfree(info->hdr);
1971 
1972 	return err;
1973 }
1974 
free_copy(struct load_info * info,int flags)1975 static void free_copy(struct load_info *info, int flags)
1976 {
1977 	if (flags & MODULE_INIT_COMPRESSED_FILE)
1978 		module_decompress_cleanup(info);
1979 	else
1980 		vfree(info->hdr);
1981 }
1982 
rewrite_section_headers(struct load_info * info,int flags)1983 static int rewrite_section_headers(struct load_info *info, int flags)
1984 {
1985 	unsigned int i;
1986 
1987 	/* This should always be true, but let's be sure. */
1988 	info->sechdrs[0].sh_addr = 0;
1989 
1990 	for (i = 1; i < info->hdr->e_shnum; i++) {
1991 		Elf_Shdr *shdr = &info->sechdrs[i];
1992 
1993 		/*
1994 		 * Mark all sections sh_addr with their address in the
1995 		 * temporary image.
1996 		 */
1997 		shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
1998 
1999 	}
2000 
2001 	/* Track but don't keep modinfo and version sections. */
2002 	info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
2003 	info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
2004 
2005 	return 0;
2006 }
2007 
2008 /*
2009  * These calls taint the kernel depending certain module circumstances */
module_augment_kernel_taints(struct module * mod,struct load_info * info)2010 static void module_augment_kernel_taints(struct module *mod, struct load_info *info)
2011 {
2012 	int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE);
2013 
2014 	if (!get_modinfo(info, "intree")) {
2015 		if (!test_taint(TAINT_OOT_MODULE))
2016 			pr_warn("%s: loading out-of-tree module taints kernel.\n",
2017 				mod->name);
2018 		add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
2019 	}
2020 
2021 	check_modinfo_retpoline(mod, info);
2022 
2023 	if (get_modinfo(info, "staging")) {
2024 		add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
2025 		pr_warn("%s: module is from the staging directory, the quality "
2026 			"is unknown, you have been warned.\n", mod->name);
2027 	}
2028 
2029 	if (is_livepatch_module(mod)) {
2030 		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
2031 		pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
2032 				mod->name);
2033 	}
2034 
2035 	module_license_taint_check(mod, get_modinfo(info, "license"));
2036 
2037 	if (get_modinfo(info, "test")) {
2038 		if (!test_taint(TAINT_TEST))
2039 			pr_warn("%s: loading test module taints kernel.\n",
2040 				mod->name);
2041 		add_taint_module(mod, TAINT_TEST, LOCKDEP_STILL_OK);
2042 	}
2043 #ifdef CONFIG_MODULE_SIG
2044 	mod->sig_ok = info->sig_ok;
2045 	if (!mod->sig_ok) {
2046 		pr_notice_once("%s: module verification failed: signature "
2047 			       "and/or required key missing - tainting "
2048 			       "kernel\n", mod->name);
2049 		add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
2050 	}
2051 #endif
2052 
2053 	/*
2054 	 * ndiswrapper is under GPL by itself, but loads proprietary modules.
2055 	 * Don't use add_taint_module(), as it would prevent ndiswrapper from
2056 	 * using GPL-only symbols it needs.
2057 	 */
2058 	if (strcmp(mod->name, "ndiswrapper") == 0)
2059 		add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
2060 
2061 	/* driverloader was caught wrongly pretending to be under GPL */
2062 	if (strcmp(mod->name, "driverloader") == 0)
2063 		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2064 				 LOCKDEP_NOW_UNRELIABLE);
2065 
2066 	/* lve claims to be GPL but upstream won't provide source */
2067 	if (strcmp(mod->name, "lve") == 0)
2068 		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2069 				 LOCKDEP_NOW_UNRELIABLE);
2070 
2071 	if (!prev_taint && test_taint(TAINT_PROPRIETARY_MODULE))
2072 		pr_warn("%s: module license taints kernel.\n", mod->name);
2073 
2074 }
2075 
check_modinfo(struct module * mod,struct load_info * info,int flags)2076 static int check_modinfo(struct module *mod, struct load_info *info, int flags)
2077 {
2078 	const char *modmagic = get_modinfo(info, "vermagic");
2079 	int err;
2080 
2081 	if (flags & MODULE_INIT_IGNORE_VERMAGIC)
2082 		modmagic = NULL;
2083 
2084 	/* This is allowed: modprobe --force will invalidate it. */
2085 	if (!modmagic) {
2086 		err = try_to_force_load(mod, "bad vermagic");
2087 		if (err)
2088 			return err;
2089 	} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
2090 		pr_err("%s: version magic '%s' should be '%s'\n",
2091 		       info->name, modmagic, vermagic);
2092 		return -ENOEXEC;
2093 	}
2094 
2095 	err = check_modinfo_livepatch(mod, info);
2096 	if (err)
2097 		return err;
2098 
2099 	return 0;
2100 }
2101 
find_module_sections(struct module * mod,struct load_info * info)2102 static int find_module_sections(struct module *mod, struct load_info *info)
2103 {
2104 	mod->kp = section_objs(info, "__param",
2105 			       sizeof(*mod->kp), &mod->num_kp);
2106 	mod->syms = section_objs(info, "__ksymtab",
2107 				 sizeof(*mod->syms), &mod->num_syms);
2108 	mod->crcs = section_addr(info, "__kcrctab");
2109 	mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
2110 				     sizeof(*mod->gpl_syms),
2111 				     &mod->num_gpl_syms);
2112 	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
2113 
2114 #ifdef CONFIG_CONSTRUCTORS
2115 	mod->ctors = section_objs(info, ".ctors",
2116 				  sizeof(*mod->ctors), &mod->num_ctors);
2117 	if (!mod->ctors)
2118 		mod->ctors = section_objs(info, ".init_array",
2119 				sizeof(*mod->ctors), &mod->num_ctors);
2120 	else if (find_sec(info, ".init_array")) {
2121 		/*
2122 		 * This shouldn't happen with same compiler and binutils
2123 		 * building all parts of the module.
2124 		 */
2125 		pr_warn("%s: has both .ctors and .init_array.\n",
2126 		       mod->name);
2127 		return -EINVAL;
2128 	}
2129 #endif
2130 
2131 	mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
2132 						&mod->noinstr_text_size);
2133 
2134 #ifdef CONFIG_TRACEPOINTS
2135 	mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
2136 					     sizeof(*mod->tracepoints_ptrs),
2137 					     &mod->num_tracepoints);
2138 #endif
2139 #ifdef CONFIG_TREE_SRCU
2140 	mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs",
2141 					     sizeof(*mod->srcu_struct_ptrs),
2142 					     &mod->num_srcu_structs);
2143 #endif
2144 #ifdef CONFIG_BPF_EVENTS
2145 	mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map",
2146 					   sizeof(*mod->bpf_raw_events),
2147 					   &mod->num_bpf_raw_events);
2148 #endif
2149 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
2150 	mod->btf_data = any_section_objs(info, ".BTF", 1, &mod->btf_data_size);
2151 #endif
2152 #ifdef CONFIG_JUMP_LABEL
2153 	mod->jump_entries = section_objs(info, "__jump_table",
2154 					sizeof(*mod->jump_entries),
2155 					&mod->num_jump_entries);
2156 #endif
2157 #ifdef CONFIG_EVENT_TRACING
2158 	mod->trace_events = section_objs(info, "_ftrace_events",
2159 					 sizeof(*mod->trace_events),
2160 					 &mod->num_trace_events);
2161 	mod->trace_evals = section_objs(info, "_ftrace_eval_map",
2162 					sizeof(*mod->trace_evals),
2163 					&mod->num_trace_evals);
2164 #endif
2165 #ifdef CONFIG_TRACING
2166 	mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
2167 					 sizeof(*mod->trace_bprintk_fmt_start),
2168 					 &mod->num_trace_bprintk_fmt);
2169 #endif
2170 #ifdef CONFIG_FTRACE_MCOUNT_RECORD
2171 	/* sechdrs[0].sh_size is always zero */
2172 	mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
2173 					     sizeof(*mod->ftrace_callsites),
2174 					     &mod->num_ftrace_callsites);
2175 #endif
2176 #ifdef CONFIG_FUNCTION_ERROR_INJECTION
2177 	mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
2178 					    sizeof(*mod->ei_funcs),
2179 					    &mod->num_ei_funcs);
2180 #endif
2181 #ifdef CONFIG_KPROBES
2182 	mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
2183 						&mod->kprobes_text_size);
2184 	mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
2185 						sizeof(unsigned long),
2186 						&mod->num_kprobe_blacklist);
2187 #endif
2188 #ifdef CONFIG_PRINTK_INDEX
2189 	mod->printk_index_start = section_objs(info, ".printk_index",
2190 					       sizeof(*mod->printk_index_start),
2191 					       &mod->printk_index_size);
2192 #endif
2193 #ifdef CONFIG_HAVE_STATIC_CALL_INLINE
2194 	mod->static_call_sites = section_objs(info, ".static_call_sites",
2195 					      sizeof(*mod->static_call_sites),
2196 					      &mod->num_static_call_sites);
2197 #endif
2198 #if IS_ENABLED(CONFIG_KUNIT)
2199 	mod->kunit_suites = section_objs(info, ".kunit_test_suites",
2200 					      sizeof(*mod->kunit_suites),
2201 					      &mod->num_kunit_suites);
2202 #endif
2203 
2204 	mod->extable = section_objs(info, "__ex_table",
2205 				    sizeof(*mod->extable), &mod->num_exentries);
2206 
2207 	if (section_addr(info, "__obsparm"))
2208 		pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
2209 
2210 #ifdef CONFIG_DYNAMIC_DEBUG_CORE
2211 	mod->dyndbg_info.descs = section_objs(info, "__dyndbg",
2212 					      sizeof(*mod->dyndbg_info.descs),
2213 					      &mod->dyndbg_info.num_descs);
2214 	mod->dyndbg_info.classes = section_objs(info, "__dyndbg_classes",
2215 						sizeof(*mod->dyndbg_info.classes),
2216 						&mod->dyndbg_info.num_classes);
2217 #endif
2218 
2219 	return 0;
2220 }
2221 
move_module(struct module * mod,struct load_info * info)2222 static int move_module(struct module *mod, struct load_info *info)
2223 {
2224 	int i;
2225 	void *ptr;
2226 	enum mod_mem_type t = 0;
2227 	int ret = -ENOMEM;
2228 
2229 	for_each_mod_mem_type(type) {
2230 		if (!mod->mem[type].size) {
2231 			mod->mem[type].base = NULL;
2232 			continue;
2233 		}
2234 		mod->mem[type].size = PAGE_ALIGN(mod->mem[type].size);
2235 		ptr = module_memory_alloc(mod->mem[type].size, type);
2236 		/*
2237                  * The pointer to these blocks of memory are stored on the module
2238                  * structure and we keep that around so long as the module is
2239                  * around. We only free that memory when we unload the module.
2240                  * Just mark them as not being a leak then. The .init* ELF
2241                  * sections *do* get freed after boot so we *could* treat them
2242                  * slightly differently with kmemleak_ignore() and only grey
2243                  * them out as they work as typical memory allocations which
2244                  * *do* eventually get freed, but let's just keep things simple
2245                  * and avoid *any* false positives.
2246 		 */
2247 		kmemleak_not_leak(ptr);
2248 		if (!ptr) {
2249 			t = type;
2250 			goto out_enomem;
2251 		}
2252 		memset(ptr, 0, mod->mem[type].size);
2253 		mod->mem[type].base = ptr;
2254 	}
2255 
2256 	/* Transfer each section which specifies SHF_ALLOC */
2257 	pr_debug("Final section addresses for %s:\n", mod->name);
2258 	for (i = 0; i < info->hdr->e_shnum; i++) {
2259 		void *dest;
2260 		Elf_Shdr *shdr = &info->sechdrs[i];
2261 		enum mod_mem_type type = shdr->sh_entsize >> SH_ENTSIZE_TYPE_SHIFT;
2262 
2263 		if (!(shdr->sh_flags & SHF_ALLOC))
2264 			continue;
2265 
2266 		dest = mod->mem[type].base + (shdr->sh_entsize & SH_ENTSIZE_OFFSET_MASK);
2267 
2268 		if (shdr->sh_type != SHT_NOBITS) {
2269 			/*
2270 			 * Our ELF checker already validated this, but let's
2271 			 * be pedantic and make the goal clearer. We actually
2272 			 * end up copying over all modifications made to the
2273 			 * userspace copy of the entire struct module.
2274 			 */
2275 			if (i == info->index.mod &&
2276 			   (WARN_ON_ONCE(shdr->sh_size != sizeof(struct module)))) {
2277 				ret = -ENOEXEC;
2278 				goto out_enomem;
2279 			}
2280 			memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
2281 		}
2282 		/*
2283 		 * Update the userspace copy's ELF section address to point to
2284 		 * our newly allocated memory as a pure convenience so that
2285 		 * users of info can keep taking advantage and using the newly
2286 		 * minted official memory area.
2287 		 */
2288 		shdr->sh_addr = (unsigned long)dest;
2289 		pr_debug("\t0x%lx 0x%.8lx %s\n", (long)shdr->sh_addr,
2290 			 (long)shdr->sh_size, info->secstrings + shdr->sh_name);
2291 	}
2292 
2293 	return 0;
2294 out_enomem:
2295 	for (t--; t >= 0; t--)
2296 		module_memory_free(mod->mem[t].base, t);
2297 	return ret;
2298 }
2299 
check_export_symbol_versions(struct module * mod)2300 static int check_export_symbol_versions(struct module *mod)
2301 {
2302 #ifdef CONFIG_MODVERSIONS
2303 	if ((mod->num_syms && !mod->crcs) ||
2304 	    (mod->num_gpl_syms && !mod->gpl_crcs)) {
2305 		return try_to_force_load(mod,
2306 					 "no versions for exported symbols");
2307 	}
2308 #endif
2309 	return 0;
2310 }
2311 
flush_module_icache(const struct module * mod)2312 static void flush_module_icache(const struct module *mod)
2313 {
2314 	/*
2315 	 * Flush the instruction cache, since we've played with text.
2316 	 * Do it before processing of module parameters, so the module
2317 	 * can provide parameter accessor functions of its own.
2318 	 */
2319 	for_each_mod_mem_type(type) {
2320 		const struct module_memory *mod_mem = &mod->mem[type];
2321 
2322 		if (mod_mem->size) {
2323 			flush_icache_range((unsigned long)mod_mem->base,
2324 					   (unsigned long)mod_mem->base + mod_mem->size);
2325 		}
2326 	}
2327 }
2328 
module_elf_check_arch(Elf_Ehdr * hdr)2329 bool __weak module_elf_check_arch(Elf_Ehdr *hdr)
2330 {
2331 	return true;
2332 }
2333 
module_frob_arch_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)2334 int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
2335 				     Elf_Shdr *sechdrs,
2336 				     char *secstrings,
2337 				     struct module *mod)
2338 {
2339 	return 0;
2340 }
2341 
2342 /* module_blacklist is a comma-separated list of module names */
2343 static char *module_blacklist;
blacklisted(const char * module_name)2344 static bool blacklisted(const char *module_name)
2345 {
2346 	const char *p;
2347 	size_t len;
2348 
2349 	if (!module_blacklist)
2350 		return false;
2351 
2352 	for (p = module_blacklist; *p; p += len) {
2353 		len = strcspn(p, ",");
2354 		if (strlen(module_name) == len && !memcmp(module_name, p, len))
2355 			return true;
2356 		if (p[len] == ',')
2357 			len++;
2358 	}
2359 	return false;
2360 }
2361 core_param(module_blacklist, module_blacklist, charp, 0400);
2362 
layout_and_allocate(struct load_info * info,int flags)2363 static struct module *layout_and_allocate(struct load_info *info, int flags)
2364 {
2365 	struct module *mod;
2366 	unsigned int ndx;
2367 	int err;
2368 
2369 	/* Allow arches to frob section contents and sizes.  */
2370 	err = module_frob_arch_sections(info->hdr, info->sechdrs,
2371 					info->secstrings, info->mod);
2372 	if (err < 0)
2373 		return ERR_PTR(err);
2374 
2375 	err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
2376 					  info->secstrings, info->mod);
2377 	if (err < 0)
2378 		return ERR_PTR(err);
2379 
2380 	/* We will do a special allocation for per-cpu sections later. */
2381 	info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
2382 
2383 	/*
2384 	 * Mark ro_after_init section with SHF_RO_AFTER_INIT so that
2385 	 * layout_sections() can put it in the right place.
2386 	 * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
2387 	 */
2388 	ndx = find_sec(info, ".data..ro_after_init");
2389 	if (ndx)
2390 		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
2391 	/*
2392 	 * Mark the __jump_table section as ro_after_init as well: these data
2393 	 * structures are never modified, with the exception of entries that
2394 	 * refer to code in the __init section, which are annotated as such
2395 	 * at module load time.
2396 	 */
2397 	ndx = find_sec(info, "__jump_table");
2398 	if (ndx)
2399 		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
2400 
2401 	/*
2402 	 * Determine total sizes, and put offsets in sh_entsize.  For now
2403 	 * this is done generically; there doesn't appear to be any
2404 	 * special cases for the architectures.
2405 	 */
2406 	layout_sections(info->mod, info);
2407 	layout_symtab(info->mod, info);
2408 
2409 	/* Allocate and move to the final place */
2410 	err = move_module(info->mod, info);
2411 	if (err)
2412 		return ERR_PTR(err);
2413 
2414 	/* Module has been copied to its final place now: return it. */
2415 	mod = (void *)info->sechdrs[info->index.mod].sh_addr;
2416 	kmemleak_load_module(mod, info);
2417 	return mod;
2418 }
2419 
2420 /* mod is no longer valid after this! */
module_deallocate(struct module * mod,struct load_info * info)2421 static void module_deallocate(struct module *mod, struct load_info *info)
2422 {
2423 	percpu_modfree(mod);
2424 	module_arch_freeing_init(mod);
2425 
2426 	free_mod_mem(mod);
2427 }
2428 
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)2429 int __weak module_finalize(const Elf_Ehdr *hdr,
2430 			   const Elf_Shdr *sechdrs,
2431 			   struct module *me)
2432 {
2433 	return 0;
2434 }
2435 
post_relocation(struct module * mod,const struct load_info * info)2436 static int post_relocation(struct module *mod, const struct load_info *info)
2437 {
2438 	/* Sort exception table now relocations are done. */
2439 	sort_extable(mod->extable, mod->extable + mod->num_exentries);
2440 
2441 	/* Copy relocated percpu area over. */
2442 	percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
2443 		       info->sechdrs[info->index.pcpu].sh_size);
2444 
2445 	/* Setup kallsyms-specific fields. */
2446 	add_kallsyms(mod, info);
2447 
2448 	/* Arch-specific module finalizing. */
2449 	return module_finalize(info->hdr, info->sechdrs, mod);
2450 }
2451 
2452 /* Call module constructors. */
do_mod_ctors(struct module * mod)2453 static void do_mod_ctors(struct module *mod)
2454 {
2455 #ifdef CONFIG_CONSTRUCTORS
2456 	unsigned long i;
2457 
2458 	for (i = 0; i < mod->num_ctors; i++)
2459 		mod->ctors[i]();
2460 #endif
2461 }
2462 
2463 /* For freeing module_init on success, in case kallsyms traversing */
2464 struct mod_initfree {
2465 	struct llist_node node;
2466 	void *init_text;
2467 	void *init_data;
2468 	void *init_rodata;
2469 };
2470 
do_free_init(struct work_struct * w)2471 static void do_free_init(struct work_struct *w)
2472 {
2473 	struct llist_node *pos, *n, *list;
2474 	struct mod_initfree *initfree;
2475 
2476 	list = llist_del_all(&init_free_list);
2477 
2478 	synchronize_rcu();
2479 
2480 	llist_for_each_safe(pos, n, list) {
2481 		initfree = container_of(pos, struct mod_initfree, node);
2482 		module_memfree(initfree->init_text);
2483 		module_memfree(initfree->init_data);
2484 		module_memfree(initfree->init_rodata);
2485 		kfree(initfree);
2486 	}
2487 }
2488 
2489 #undef MODULE_PARAM_PREFIX
2490 #define MODULE_PARAM_PREFIX "module."
2491 /* Default value for module->async_probe_requested */
2492 static bool async_probe;
2493 module_param(async_probe, bool, 0644);
2494 
2495 /*
2496  * This is where the real work happens.
2497  *
2498  * Keep it uninlined to provide a reliable breakpoint target, e.g. for the gdb
2499  * helper command 'lx-symbols'.
2500  */
do_init_module(struct module * mod)2501 static noinline int do_init_module(struct module *mod)
2502 {
2503 	int ret = 0;
2504 	struct mod_initfree *freeinit;
2505 #if defined(CONFIG_MODULE_STATS)
2506 	unsigned int text_size = 0, total_size = 0;
2507 
2508 	for_each_mod_mem_type(type) {
2509 		const struct module_memory *mod_mem = &mod->mem[type];
2510 		if (mod_mem->size) {
2511 			total_size += mod_mem->size;
2512 			if (type == MOD_TEXT || type == MOD_INIT_TEXT)
2513 				text_size += mod_mem->size;
2514 		}
2515 	}
2516 #endif
2517 
2518 	freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
2519 	if (!freeinit) {
2520 		ret = -ENOMEM;
2521 		goto fail;
2522 	}
2523 	freeinit->init_text = mod->mem[MOD_INIT_TEXT].base;
2524 	freeinit->init_data = mod->mem[MOD_INIT_DATA].base;
2525 	freeinit->init_rodata = mod->mem[MOD_INIT_RODATA].base;
2526 
2527 	do_mod_ctors(mod);
2528 	/* Start the module */
2529 	if (mod->init != NULL)
2530 		ret = do_one_initcall(mod->init);
2531 	if (ret < 0) {
2532 		goto fail_free_freeinit;
2533 	}
2534 	if (ret > 0) {
2535 		pr_warn("%s: '%s'->init suspiciously returned %d, it should "
2536 			"follow 0/-E convention\n"
2537 			"%s: loading module anyway...\n",
2538 			__func__, mod->name, ret, __func__);
2539 		dump_stack();
2540 	}
2541 
2542 	/* Now it's a first class citizen! */
2543 	mod->state = MODULE_STATE_LIVE;
2544 	blocking_notifier_call_chain(&module_notify_list,
2545 				     MODULE_STATE_LIVE, mod);
2546 
2547 	/* Delay uevent until module has finished its init routine */
2548 	kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
2549 
2550 	/*
2551 	 * We need to finish all async code before the module init sequence
2552 	 * is done. This has potential to deadlock if synchronous module
2553 	 * loading is requested from async (which is not allowed!).
2554 	 *
2555 	 * See commit 0fdff3ec6d87 ("async, kmod: warn on synchronous
2556 	 * request_module() from async workers") for more details.
2557 	 */
2558 	if (!mod->async_probe_requested)
2559 		async_synchronize_full();
2560 
2561 	ftrace_free_mem(mod, mod->mem[MOD_INIT_TEXT].base,
2562 			mod->mem[MOD_INIT_TEXT].base + mod->mem[MOD_INIT_TEXT].size);
2563 	mutex_lock(&module_mutex);
2564 	/* Drop initial reference. */
2565 	module_put(mod);
2566 	trim_init_extable(mod);
2567 #ifdef CONFIG_KALLSYMS
2568 	/* Switch to core kallsyms now init is done: kallsyms may be walking! */
2569 	rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
2570 #endif
2571 	module_enable_ro(mod, true);
2572 	mod_tree_remove_init(mod);
2573 	module_arch_freeing_init(mod);
2574 	for_class_mod_mem_type(type, init) {
2575 		mod->mem[type].base = NULL;
2576 		mod->mem[type].size = 0;
2577 	}
2578 
2579 #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
2580 	/* .BTF is not SHF_ALLOC and will get removed, so sanitize pointer */
2581 	mod->btf_data = NULL;
2582 #endif
2583 	/*
2584 	 * We want to free module_init, but be aware that kallsyms may be
2585 	 * walking this with preempt disabled.  In all the failure paths, we
2586 	 * call synchronize_rcu(), but we don't want to slow down the success
2587 	 * path. module_memfree() cannot be called in an interrupt, so do the
2588 	 * work and call synchronize_rcu() in a work queue.
2589 	 *
2590 	 * Note that module_alloc() on most architectures creates W+X page
2591 	 * mappings which won't be cleaned up until do_free_init() runs.  Any
2592 	 * code such as mark_rodata_ro() which depends on those mappings to
2593 	 * be cleaned up needs to sync with the queued work - ie
2594 	 * rcu_barrier()
2595 	 */
2596 	if (llist_add(&freeinit->node, &init_free_list))
2597 		schedule_work(&init_free_wq);
2598 
2599 	mutex_unlock(&module_mutex);
2600 	wake_up_all(&module_wq);
2601 
2602 	mod_stat_add_long(text_size, &total_text_size);
2603 	mod_stat_add_long(total_size, &total_mod_size);
2604 
2605 	mod_stat_inc(&modcount);
2606 
2607 	return 0;
2608 
2609 fail_free_freeinit:
2610 	kfree(freeinit);
2611 fail:
2612 	/* Try to protect us from buggy refcounters. */
2613 	mod->state = MODULE_STATE_GOING;
2614 	synchronize_rcu();
2615 	module_put(mod);
2616 	blocking_notifier_call_chain(&module_notify_list,
2617 				     MODULE_STATE_GOING, mod);
2618 	klp_module_going(mod);
2619 	ftrace_release_mod(mod);
2620 	free_module(mod);
2621 	wake_up_all(&module_wq);
2622 
2623 	return ret;
2624 }
2625 
may_init_module(void)2626 static int may_init_module(void)
2627 {
2628 	if (!capable(CAP_SYS_MODULE) || modules_disabled)
2629 		return -EPERM;
2630 
2631 	return 0;
2632 }
2633 
2634 /* Is this module of this name done loading?  No locks held. */
finished_loading(const char * name)2635 static bool finished_loading(const char *name)
2636 {
2637 	struct module *mod;
2638 	bool ret;
2639 
2640 	/*
2641 	 * The module_mutex should not be a heavily contended lock;
2642 	 * if we get the occasional sleep here, we'll go an extra iteration
2643 	 * in the wait_event_interruptible(), which is harmless.
2644 	 */
2645 	sched_annotate_sleep();
2646 	mutex_lock(&module_mutex);
2647 	mod = find_module_all(name, strlen(name), true);
2648 	ret = !mod || mod->state == MODULE_STATE_LIVE
2649 		|| mod->state == MODULE_STATE_GOING;
2650 	mutex_unlock(&module_mutex);
2651 
2652 	return ret;
2653 }
2654 
2655 /* Must be called with module_mutex held */
module_patient_check_exists(const char * name,enum fail_dup_mod_reason reason)2656 static int module_patient_check_exists(const char *name,
2657 				       enum fail_dup_mod_reason reason)
2658 {
2659 	struct module *old;
2660 	int err = 0;
2661 
2662 	old = find_module_all(name, strlen(name), true);
2663 	if (old == NULL)
2664 		return 0;
2665 
2666 	if (old->state == MODULE_STATE_COMING ||
2667 	    old->state == MODULE_STATE_UNFORMED) {
2668 		/* Wait in case it fails to load. */
2669 		mutex_unlock(&module_mutex);
2670 		err = wait_event_interruptible(module_wq,
2671 				       finished_loading(name));
2672 		mutex_lock(&module_mutex);
2673 		if (err)
2674 			return err;
2675 
2676 		/* The module might have gone in the meantime. */
2677 		old = find_module_all(name, strlen(name), true);
2678 	}
2679 
2680 	if (try_add_failed_module(name, reason))
2681 		pr_warn("Could not add fail-tracking for module: %s\n", name);
2682 
2683 	/*
2684 	 * We are here only when the same module was being loaded. Do
2685 	 * not try to load it again right now. It prevents long delays
2686 	 * caused by serialized module load failures. It might happen
2687 	 * when more devices of the same type trigger load of
2688 	 * a particular module.
2689 	 */
2690 	if (old && old->state == MODULE_STATE_LIVE)
2691 		return -EEXIST;
2692 	return -EBUSY;
2693 }
2694 
2695 /*
2696  * We try to place it in the list now to make sure it's unique before
2697  * we dedicate too many resources.  In particular, temporary percpu
2698  * memory exhaustion.
2699  */
add_unformed_module(struct module * mod)2700 static int add_unformed_module(struct module *mod)
2701 {
2702 	int err;
2703 
2704 	mod->state = MODULE_STATE_UNFORMED;
2705 
2706 	mutex_lock(&module_mutex);
2707 	err = module_patient_check_exists(mod->name, FAIL_DUP_MOD_LOAD);
2708 	if (err)
2709 		goto out;
2710 
2711 	mod_update_bounds(mod);
2712 	list_add_rcu(&mod->list, &modules);
2713 	mod_tree_insert(mod);
2714 	err = 0;
2715 
2716 out:
2717 	mutex_unlock(&module_mutex);
2718 	return err;
2719 }
2720 
complete_formation(struct module * mod,struct load_info * info)2721 static int complete_formation(struct module *mod, struct load_info *info)
2722 {
2723 	int err;
2724 
2725 	mutex_lock(&module_mutex);
2726 
2727 	/* Find duplicate symbols (must be called under lock). */
2728 	err = verify_exported_symbols(mod);
2729 	if (err < 0)
2730 		goto out;
2731 
2732 	/* These rely on module_mutex for list integrity. */
2733 	module_bug_finalize(info->hdr, info->sechdrs, mod);
2734 	module_cfi_finalize(info->hdr, info->sechdrs, mod);
2735 
2736 	module_enable_ro(mod, false);
2737 	module_enable_nx(mod);
2738 	module_enable_x(mod);
2739 
2740 	/*
2741 	 * Mark state as coming so strong_try_module_get() ignores us,
2742 	 * but kallsyms etc. can see us.
2743 	 */
2744 	mod->state = MODULE_STATE_COMING;
2745 	mutex_unlock(&module_mutex);
2746 
2747 	return 0;
2748 
2749 out:
2750 	mutex_unlock(&module_mutex);
2751 	return err;
2752 }
2753 
prepare_coming_module(struct module * mod)2754 static int prepare_coming_module(struct module *mod)
2755 {
2756 	int err;
2757 
2758 	ftrace_module_enable(mod);
2759 	err = klp_module_coming(mod);
2760 	if (err)
2761 		return err;
2762 
2763 	err = blocking_notifier_call_chain_robust(&module_notify_list,
2764 			MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
2765 	err = notifier_to_errno(err);
2766 	if (err)
2767 		klp_module_going(mod);
2768 
2769 	return err;
2770 }
2771 
unknown_module_param_cb(char * param,char * val,const char * modname,void * arg)2772 static int unknown_module_param_cb(char *param, char *val, const char *modname,
2773 				   void *arg)
2774 {
2775 	struct module *mod = arg;
2776 	int ret;
2777 
2778 	if (strcmp(param, "async_probe") == 0) {
2779 		if (kstrtobool(val, &mod->async_probe_requested))
2780 			mod->async_probe_requested = true;
2781 		return 0;
2782 	}
2783 
2784 	/* Check for magic 'dyndbg' arg */
2785 	ret = ddebug_dyndbg_module_param_cb(param, val, modname);
2786 	if (ret != 0)
2787 		pr_warn("%s: unknown parameter '%s' ignored\n", modname, param);
2788 	return 0;
2789 }
2790 
2791 /* Module within temporary copy, this doesn't do any allocation  */
early_mod_check(struct load_info * info,int flags)2792 static int early_mod_check(struct load_info *info, int flags)
2793 {
2794 	int err;
2795 
2796 	/*
2797 	 * Now that we know we have the correct module name, check
2798 	 * if it's blacklisted.
2799 	 */
2800 	if (blacklisted(info->name)) {
2801 		pr_err("Module %s is blacklisted\n", info->name);
2802 		return -EPERM;
2803 	}
2804 
2805 	err = rewrite_section_headers(info, flags);
2806 	if (err)
2807 		return err;
2808 
2809 	/* Check module struct version now, before we try to use module. */
2810 	if (!check_modstruct_version(info, info->mod))
2811 		return -ENOEXEC;
2812 
2813 	err = check_modinfo(info->mod, info, flags);
2814 	if (err)
2815 		return err;
2816 
2817 	mutex_lock(&module_mutex);
2818 	err = module_patient_check_exists(info->mod->name, FAIL_DUP_MOD_BECOMING);
2819 	mutex_unlock(&module_mutex);
2820 
2821 	return err;
2822 }
2823 
2824 /*
2825  * Allocate and load the module: note that size of section 0 is always
2826  * zero, and we rely on this for optional sections.
2827  */
load_module(struct load_info * info,const char __user * uargs,int flags)2828 static int load_module(struct load_info *info, const char __user *uargs,
2829 		       int flags)
2830 {
2831 	struct module *mod;
2832 	bool module_allocated = false;
2833 	long err = 0;
2834 	char *after_dashes;
2835 
2836 	/*
2837 	 * Do the signature check (if any) first. All that
2838 	 * the signature check needs is info->len, it does
2839 	 * not need any of the section info. That can be
2840 	 * set up later. This will minimize the chances
2841 	 * of a corrupt module causing problems before
2842 	 * we even get to the signature check.
2843 	 *
2844 	 * The check will also adjust info->len by stripping
2845 	 * off the sig length at the end of the module, making
2846 	 * checks against info->len more correct.
2847 	 */
2848 	err = module_sig_check(info, flags);
2849 	if (err)
2850 		goto free_copy;
2851 
2852 	/*
2853 	 * Do basic sanity checks against the ELF header and
2854 	 * sections. Cache useful sections and set the
2855 	 * info->mod to the userspace passed struct module.
2856 	 */
2857 	err = elf_validity_cache_copy(info, flags);
2858 	if (err)
2859 		goto free_copy;
2860 
2861 	err = early_mod_check(info, flags);
2862 	if (err)
2863 		goto free_copy;
2864 
2865 	/* Figure out module layout, and allocate all the memory. */
2866 	mod = layout_and_allocate(info, flags);
2867 	if (IS_ERR(mod)) {
2868 		err = PTR_ERR(mod);
2869 		goto free_copy;
2870 	}
2871 
2872 	module_allocated = true;
2873 
2874 	audit_log_kern_module(mod->name);
2875 
2876 	/* Reserve our place in the list. */
2877 	err = add_unformed_module(mod);
2878 	if (err)
2879 		goto free_module;
2880 
2881 	/*
2882 	 * We are tainting your kernel if your module gets into
2883 	 * the modules linked list somehow.
2884 	 */
2885 	module_augment_kernel_taints(mod, info);
2886 
2887 	/* To avoid stressing percpu allocator, do this once we're unique. */
2888 	err = percpu_modalloc(mod, info);
2889 	if (err)
2890 		goto unlink_mod;
2891 
2892 	/* Now module is in final location, initialize linked lists, etc. */
2893 	err = module_unload_init(mod);
2894 	if (err)
2895 		goto unlink_mod;
2896 
2897 	init_param_lock(mod);
2898 
2899 	/*
2900 	 * Now we've got everything in the final locations, we can
2901 	 * find optional sections.
2902 	 */
2903 	err = find_module_sections(mod, info);
2904 	if (err)
2905 		goto free_unload;
2906 
2907 	err = check_export_symbol_versions(mod);
2908 	if (err)
2909 		goto free_unload;
2910 
2911 	/* Set up MODINFO_ATTR fields */
2912 	setup_modinfo(mod, info);
2913 
2914 	/* Fix up syms, so that st_value is a pointer to location. */
2915 	err = simplify_symbols(mod, info);
2916 	if (err < 0)
2917 		goto free_modinfo;
2918 
2919 	err = apply_relocations(mod, info);
2920 	if (err < 0)
2921 		goto free_modinfo;
2922 
2923 	err = post_relocation(mod, info);
2924 	if (err < 0)
2925 		goto free_modinfo;
2926 
2927 	flush_module_icache(mod);
2928 
2929 	/* Now copy in args */
2930 	mod->args = strndup_user(uargs, ~0UL >> 1);
2931 	if (IS_ERR(mod->args)) {
2932 		err = PTR_ERR(mod->args);
2933 		goto free_arch_cleanup;
2934 	}
2935 
2936 	init_build_id(mod, info);
2937 
2938 	/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
2939 	ftrace_module_init(mod);
2940 
2941 	/* Finally it's fully formed, ready to start executing. */
2942 	err = complete_formation(mod, info);
2943 	if (err)
2944 		goto ddebug_cleanup;
2945 
2946 	err = prepare_coming_module(mod);
2947 	if (err)
2948 		goto bug_cleanup;
2949 
2950 	mod->async_probe_requested = async_probe;
2951 
2952 	/* Module is ready to execute: parsing args may do that. */
2953 	after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
2954 				  -32768, 32767, mod,
2955 				  unknown_module_param_cb);
2956 	if (IS_ERR(after_dashes)) {
2957 		err = PTR_ERR(after_dashes);
2958 		goto coming_cleanup;
2959 	} else if (after_dashes) {
2960 		pr_warn("%s: parameters '%s' after `--' ignored\n",
2961 		       mod->name, after_dashes);
2962 	}
2963 
2964 	/* Link in to sysfs. */
2965 	err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
2966 	if (err < 0)
2967 		goto coming_cleanup;
2968 
2969 	if (is_livepatch_module(mod)) {
2970 		err = copy_module_elf(mod, info);
2971 		if (err < 0)
2972 			goto sysfs_cleanup;
2973 	}
2974 
2975 	/* Get rid of temporary copy. */
2976 	free_copy(info, flags);
2977 
2978 	/* Done! */
2979 	trace_module_load(mod);
2980 
2981 	return do_init_module(mod);
2982 
2983  sysfs_cleanup:
2984 	mod_sysfs_teardown(mod);
2985  coming_cleanup:
2986 	mod->state = MODULE_STATE_GOING;
2987 	destroy_params(mod->kp, mod->num_kp);
2988 	blocking_notifier_call_chain(&module_notify_list,
2989 				     MODULE_STATE_GOING, mod);
2990 	klp_module_going(mod);
2991  bug_cleanup:
2992 	mod->state = MODULE_STATE_GOING;
2993 	/* module_bug_cleanup needs module_mutex protection */
2994 	mutex_lock(&module_mutex);
2995 	module_bug_cleanup(mod);
2996 	mutex_unlock(&module_mutex);
2997 
2998  ddebug_cleanup:
2999 	ftrace_release_mod(mod);
3000 	synchronize_rcu();
3001 	kfree(mod->args);
3002  free_arch_cleanup:
3003 	module_arch_cleanup(mod);
3004  free_modinfo:
3005 	free_modinfo(mod);
3006  free_unload:
3007 	module_unload_free(mod);
3008  unlink_mod:
3009 	mutex_lock(&module_mutex);
3010 	/* Unlink carefully: kallsyms could be walking list. */
3011 	list_del_rcu(&mod->list);
3012 	mod_tree_remove(mod);
3013 	wake_up_all(&module_wq);
3014 	/* Wait for RCU-sched synchronizing before releasing mod->list. */
3015 	synchronize_rcu();
3016 	mutex_unlock(&module_mutex);
3017  free_module:
3018 	mod_stat_bump_invalid(info, flags);
3019 	/* Free lock-classes; relies on the preceding sync_rcu() */
3020 	for_class_mod_mem_type(type, core_data) {
3021 		lockdep_free_key_range(mod->mem[type].base,
3022 				       mod->mem[type].size);
3023 	}
3024 
3025 	module_deallocate(mod, info);
3026  free_copy:
3027 	/*
3028 	 * The info->len is always set. We distinguish between
3029 	 * failures once the proper module was allocated and
3030 	 * before that.
3031 	 */
3032 	if (!module_allocated)
3033 		mod_stat_bump_becoming(info, flags);
3034 	free_copy(info, flags);
3035 	return err;
3036 }
3037 
SYSCALL_DEFINE3(init_module,void __user *,umod,unsigned long,len,const char __user *,uargs)3038 SYSCALL_DEFINE3(init_module, void __user *, umod,
3039 		unsigned long, len, const char __user *, uargs)
3040 {
3041 	int err;
3042 	struct load_info info = { };
3043 
3044 	err = may_init_module();
3045 	if (err)
3046 		return err;
3047 
3048 	pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
3049 	       umod, len, uargs);
3050 
3051 	err = copy_module_from_user(umod, len, &info);
3052 	if (err) {
3053 		mod_stat_inc(&failed_kreads);
3054 		mod_stat_add_long(len, &invalid_kread_bytes);
3055 		return err;
3056 	}
3057 
3058 	return load_module(&info, uargs, 0);
3059 }
3060 
3061 struct idempotent {
3062 	const void *cookie;
3063 	struct hlist_node entry;
3064 	struct completion complete;
3065 	int ret;
3066 };
3067 
3068 #define IDEM_HASH_BITS 8
3069 static struct hlist_head idem_hash[1 << IDEM_HASH_BITS];
3070 static DEFINE_SPINLOCK(idem_lock);
3071 
idempotent(struct idempotent * u,const void * cookie)3072 static bool idempotent(struct idempotent *u, const void *cookie)
3073 {
3074 	int hash = hash_ptr(cookie, IDEM_HASH_BITS);
3075 	struct hlist_head *head = idem_hash + hash;
3076 	struct idempotent *existing;
3077 	bool first;
3078 
3079 	u->ret = 0;
3080 	u->cookie = cookie;
3081 	init_completion(&u->complete);
3082 
3083 	spin_lock(&idem_lock);
3084 	first = true;
3085 	hlist_for_each_entry(existing, head, entry) {
3086 		if (existing->cookie != cookie)
3087 			continue;
3088 		first = false;
3089 		break;
3090 	}
3091 	hlist_add_head(&u->entry, idem_hash + hash);
3092 	spin_unlock(&idem_lock);
3093 
3094 	return !first;
3095 }
3096 
3097 /*
3098  * We were the first one with 'cookie' on the list, and we ended
3099  * up completing the operation. We now need to walk the list,
3100  * remove everybody - which includes ourselves - fill in the return
3101  * value, and then complete the operation.
3102  */
idempotent_complete(struct idempotent * u,int ret)3103 static int idempotent_complete(struct idempotent *u, int ret)
3104 {
3105 	const void *cookie = u->cookie;
3106 	int hash = hash_ptr(cookie, IDEM_HASH_BITS);
3107 	struct hlist_head *head = idem_hash + hash;
3108 	struct hlist_node *next;
3109 	struct idempotent *pos;
3110 
3111 	spin_lock(&idem_lock);
3112 	hlist_for_each_entry_safe(pos, next, head, entry) {
3113 		if (pos->cookie != cookie)
3114 			continue;
3115 		hlist_del(&pos->entry);
3116 		pos->ret = ret;
3117 		complete(&pos->complete);
3118 	}
3119 	spin_unlock(&idem_lock);
3120 	return ret;
3121 }
3122 
init_module_from_file(struct file * f,const char __user * uargs,int flags)3123 static int init_module_from_file(struct file *f, const char __user * uargs, int flags)
3124 {
3125 	struct load_info info = { };
3126 	void *buf = NULL;
3127 	int len;
3128 
3129 	len = kernel_read_file(f, 0, &buf, INT_MAX, NULL, READING_MODULE);
3130 	if (len < 0) {
3131 		mod_stat_inc(&failed_kreads);
3132 		return len;
3133 	}
3134 
3135 	if (flags & MODULE_INIT_COMPRESSED_FILE) {
3136 		int err = module_decompress(&info, buf, len);
3137 		vfree(buf); /* compressed data is no longer needed */
3138 		if (err) {
3139 			mod_stat_inc(&failed_decompress);
3140 			mod_stat_add_long(len, &invalid_decompress_bytes);
3141 			return err;
3142 		}
3143 	} else {
3144 		info.hdr = buf;
3145 		info.len = len;
3146 	}
3147 
3148 	return load_module(&info, uargs, flags);
3149 }
3150 
idempotent_init_module(struct file * f,const char __user * uargs,int flags)3151 static int idempotent_init_module(struct file *f, const char __user * uargs, int flags)
3152 {
3153 	struct idempotent idem;
3154 
3155 	if (!f || !(f->f_mode & FMODE_READ))
3156 		return -EBADF;
3157 
3158 	/* See if somebody else is doing the operation? */
3159 	if (idempotent(&idem, file_inode(f))) {
3160 		wait_for_completion(&idem.complete);
3161 		return idem.ret;
3162 	}
3163 
3164 	/* Otherwise, we'll do it and complete others */
3165 	return idempotent_complete(&idem,
3166 		init_module_from_file(f, uargs, flags));
3167 }
3168 
SYSCALL_DEFINE3(finit_module,int,fd,const char __user *,uargs,int,flags)3169 SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
3170 {
3171 	int err;
3172 	struct fd f;
3173 
3174 	err = may_init_module();
3175 	if (err)
3176 		return err;
3177 
3178 	pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
3179 
3180 	if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
3181 		      |MODULE_INIT_IGNORE_VERMAGIC
3182 		      |MODULE_INIT_COMPRESSED_FILE))
3183 		return -EINVAL;
3184 
3185 	f = fdget(fd);
3186 	err = idempotent_init_module(f.file, uargs, flags);
3187 	fdput(f);
3188 	return err;
3189 }
3190 
3191 /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
module_flags(struct module * mod,char * buf,bool show_state)3192 char *module_flags(struct module *mod, char *buf, bool show_state)
3193 {
3194 	int bx = 0;
3195 
3196 	BUG_ON(mod->state == MODULE_STATE_UNFORMED);
3197 	if (!mod->taints && !show_state)
3198 		goto out;
3199 	if (mod->taints ||
3200 	    mod->state == MODULE_STATE_GOING ||
3201 	    mod->state == MODULE_STATE_COMING) {
3202 		buf[bx++] = '(';
3203 		bx += module_flags_taint(mod->taints, buf + bx);
3204 		/* Show a - for module-is-being-unloaded */
3205 		if (mod->state == MODULE_STATE_GOING && show_state)
3206 			buf[bx++] = '-';
3207 		/* Show a + for module-is-being-loaded */
3208 		if (mod->state == MODULE_STATE_COMING && show_state)
3209 			buf[bx++] = '+';
3210 		buf[bx++] = ')';
3211 	}
3212 out:
3213 	buf[bx] = '\0';
3214 
3215 	return buf;
3216 }
3217 
3218 /* Given an address, look for it in the module exception tables. */
search_module_extables(unsigned long addr)3219 const struct exception_table_entry *search_module_extables(unsigned long addr)
3220 {
3221 	const struct exception_table_entry *e = NULL;
3222 	struct module *mod;
3223 
3224 	preempt_disable();
3225 	mod = __module_address(addr);
3226 	if (!mod)
3227 		goto out;
3228 
3229 	if (!mod->num_exentries)
3230 		goto out;
3231 
3232 	e = search_extable(mod->extable,
3233 			   mod->num_exentries,
3234 			   addr);
3235 out:
3236 	preempt_enable();
3237 
3238 	/*
3239 	 * Now, if we found one, we are running inside it now, hence
3240 	 * we cannot unload the module, hence no refcnt needed.
3241 	 */
3242 	return e;
3243 }
3244 
3245 /**
3246  * is_module_address() - is this address inside a module?
3247  * @addr: the address to check.
3248  *
3249  * See is_module_text_address() if you simply want to see if the address
3250  * is code (not data).
3251  */
is_module_address(unsigned long addr)3252 bool is_module_address(unsigned long addr)
3253 {
3254 	bool ret;
3255 
3256 	preempt_disable();
3257 	ret = __module_address(addr) != NULL;
3258 	preempt_enable();
3259 
3260 	return ret;
3261 }
3262 
3263 /**
3264  * __module_address() - get the module which contains an address.
3265  * @addr: the address.
3266  *
3267  * Must be called with preempt disabled or module mutex held so that
3268  * module doesn't get freed during this.
3269  */
__module_address(unsigned long addr)3270 struct module *__module_address(unsigned long addr)
3271 {
3272 	struct module *mod;
3273 
3274 	if (addr >= mod_tree.addr_min && addr <= mod_tree.addr_max)
3275 		goto lookup;
3276 
3277 #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
3278 	if (addr >= mod_tree.data_addr_min && addr <= mod_tree.data_addr_max)
3279 		goto lookup;
3280 #endif
3281 
3282 	return NULL;
3283 
3284 lookup:
3285 	module_assert_mutex_or_preempt();
3286 
3287 	mod = mod_find(addr, &mod_tree);
3288 	if (mod) {
3289 		BUG_ON(!within_module(addr, mod));
3290 		if (mod->state == MODULE_STATE_UNFORMED)
3291 			mod = NULL;
3292 	}
3293 	return mod;
3294 }
3295 
3296 /**
3297  * is_module_text_address() - is this address inside module code?
3298  * @addr: the address to check.
3299  *
3300  * See is_module_address() if you simply want to see if the address is
3301  * anywhere in a module.  See kernel_text_address() for testing if an
3302  * address corresponds to kernel or module code.
3303  */
is_module_text_address(unsigned long addr)3304 bool is_module_text_address(unsigned long addr)
3305 {
3306 	bool ret;
3307 
3308 	preempt_disable();
3309 	ret = __module_text_address(addr) != NULL;
3310 	preempt_enable();
3311 
3312 	return ret;
3313 }
3314 
3315 /**
3316  * __module_text_address() - get the module whose code contains an address.
3317  * @addr: the address.
3318  *
3319  * Must be called with preempt disabled or module mutex held so that
3320  * module doesn't get freed during this.
3321  */
__module_text_address(unsigned long addr)3322 struct module *__module_text_address(unsigned long addr)
3323 {
3324 	struct module *mod = __module_address(addr);
3325 	if (mod) {
3326 		/* Make sure it's within the text section. */
3327 		if (!within_module_mem_type(addr, mod, MOD_TEXT) &&
3328 		    !within_module_mem_type(addr, mod, MOD_INIT_TEXT))
3329 			mod = NULL;
3330 	}
3331 	return mod;
3332 }
3333 
3334 /* Don't grab lock, we're oopsing. */
print_modules(void)3335 void print_modules(void)
3336 {
3337 	struct module *mod;
3338 	char buf[MODULE_FLAGS_BUF_SIZE];
3339 
3340 	printk(KERN_DEFAULT "Modules linked in:");
3341 	/* Most callers should already have preempt disabled, but make sure */
3342 	preempt_disable();
3343 	list_for_each_entry_rcu(mod, &modules, list) {
3344 		if (mod->state == MODULE_STATE_UNFORMED)
3345 			continue;
3346 		pr_cont(" %s%s", mod->name, module_flags(mod, buf, true));
3347 	}
3348 
3349 	print_unloaded_tainted_modules();
3350 	preempt_enable();
3351 	if (last_unloaded_module.name[0])
3352 		pr_cont(" [last unloaded: %s%s]", last_unloaded_module.name,
3353 			last_unloaded_module.taints);
3354 	pr_cont("\n");
3355 }
3356 
3357 #ifdef CONFIG_MODULE_DEBUGFS
3358 struct dentry *mod_debugfs_root;
3359 
module_debugfs_init(void)3360 static int module_debugfs_init(void)
3361 {
3362 	mod_debugfs_root = debugfs_create_dir("modules", NULL);
3363 	return 0;
3364 }
3365 module_init(module_debugfs_init);
3366 #endif
3367