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/codetag.h>
60  #include <linux/debugfs.h>
61  #include <linux/execmem.h>
62  #include <uapi/linux/module.h>
63  #include "internal.h"
64  
65  #define CREATE_TRACE_POINTS
66  #include <trace/events/module.h>
67  
68  /*
69   * Mutex protects:
70   * 1) List of modules (also safely readable with preempt_disable),
71   * 2) module_use links,
72   * 3) mod_tree.addr_min/mod_tree.addr_max.
73   * (delete and add uses RCU list operations).
74   */
75  DEFINE_MUTEX(module_mutex);
76  LIST_HEAD(modules);
77  
78  /* Work queue for freeing init sections in success case */
79  static void do_free_init(struct work_struct *w);
80  static DECLARE_WORK(init_free_wq, do_free_init);
81  static LLIST_HEAD(init_free_list);
82  
83  struct mod_tree_root mod_tree __cacheline_aligned = {
84  	.addr_min = -1UL,
85  };
86  
87  struct symsearch {
88  	const struct kernel_symbol *start, *stop;
89  	const s32 *crcs;
90  	enum mod_license license;
91  };
92  
93  /*
94   * Bounds of module memory, for speeding up __module_address.
95   * Protected by module_mutex.
96   */
__mod_update_bounds(enum mod_mem_type type __maybe_unused,void * base,unsigned int size,struct mod_tree_root * tree)97  static void __mod_update_bounds(enum mod_mem_type type __maybe_unused, void *base,
98  				unsigned int size, struct mod_tree_root *tree)
99  {
100  	unsigned long min = (unsigned long)base;
101  	unsigned long max = min + size;
102  
103  #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
104  	if (mod_mem_type_is_core_data(type)) {
105  		if (min < tree->data_addr_min)
106  			tree->data_addr_min = min;
107  		if (max > tree->data_addr_max)
108  			tree->data_addr_max = max;
109  		return;
110  	}
111  #endif
112  	if (min < tree->addr_min)
113  		tree->addr_min = min;
114  	if (max > tree->addr_max)
115  		tree->addr_max = max;
116  }
117  
mod_update_bounds(struct module * mod)118  static void mod_update_bounds(struct module *mod)
119  {
120  	for_each_mod_mem_type(type) {
121  		struct module_memory *mod_mem = &mod->mem[type];
122  
123  		if (mod_mem->size)
124  			__mod_update_bounds(type, mod_mem->base, mod_mem->size, &mod_tree);
125  	}
126  }
127  
128  /* Block module loading/unloading? */
129  int modules_disabled;
130  core_param(nomodule, modules_disabled, bint, 0);
131  
132  /* Waiting for a module to finish initializing? */
133  static DECLARE_WAIT_QUEUE_HEAD(module_wq);
134  
135  static BLOCKING_NOTIFIER_HEAD(module_notify_list);
136  
register_module_notifier(struct notifier_block * nb)137  int register_module_notifier(struct notifier_block *nb)
138  {
139  	return blocking_notifier_chain_register(&module_notify_list, nb);
140  }
141  EXPORT_SYMBOL(register_module_notifier);
142  
unregister_module_notifier(struct notifier_block * nb)143  int unregister_module_notifier(struct notifier_block *nb)
144  {
145  	return blocking_notifier_chain_unregister(&module_notify_list, nb);
146  }
147  EXPORT_SYMBOL(unregister_module_notifier);
148  
149  /*
150   * We require a truly strong try_module_get(): 0 means success.
151   * Otherwise an error is returned due to ongoing or failed
152   * initialization etc.
153   */
strong_try_module_get(struct module * mod)154  static inline int strong_try_module_get(struct module *mod)
155  {
156  	BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
157  	if (mod && mod->state == MODULE_STATE_COMING)
158  		return -EBUSY;
159  	if (try_module_get(mod))
160  		return 0;
161  	else
162  		return -ENOENT;
163  }
164  
add_taint_module(struct module * mod,unsigned flag,enum lockdep_ok lockdep_ok)165  static inline void add_taint_module(struct module *mod, unsigned flag,
166  				    enum lockdep_ok lockdep_ok)
167  {
168  	add_taint(flag, lockdep_ok);
169  	set_bit(flag, &mod->taints);
170  }
171  
172  /*
173   * A thread that wants to hold a reference to a module only while it
174   * is running can call this to safely exit.
175   */
__module_put_and_kthread_exit(struct module * mod,long code)176  void __noreturn __module_put_and_kthread_exit(struct module *mod, long code)
177  {
178  	module_put(mod);
179  	kthread_exit(code);
180  }
181  EXPORT_SYMBOL(__module_put_and_kthread_exit);
182  
183  /* Find a module section: 0 means not found. */
find_sec(const struct load_info * info,const char * name)184  static unsigned int find_sec(const struct load_info *info, const char *name)
185  {
186  	unsigned int i;
187  
188  	for (i = 1; i < info->hdr->e_shnum; i++) {
189  		Elf_Shdr *shdr = &info->sechdrs[i];
190  		/* Alloc bit cleared means "ignore it." */
191  		if ((shdr->sh_flags & SHF_ALLOC)
192  		    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
193  			return i;
194  	}
195  	return 0;
196  }
197  
198  /* Find a module section, or NULL. */
section_addr(const struct load_info * info,const char * name)199  static void *section_addr(const struct load_info *info, const char *name)
200  {
201  	/* Section 0 has sh_addr 0. */
202  	return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
203  }
204  
205  /* 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)206  static void *section_objs(const struct load_info *info,
207  			  const char *name,
208  			  size_t object_size,
209  			  unsigned int *num)
210  {
211  	unsigned int sec = find_sec(info, name);
212  
213  	/* Section 0 has sh_addr 0 and sh_size 0. */
214  	*num = info->sechdrs[sec].sh_size / object_size;
215  	return (void *)info->sechdrs[sec].sh_addr;
216  }
217  
218  /* Find a module section: 0 means not found. Ignores SHF_ALLOC flag. */
find_any_sec(const struct load_info * info,const char * name)219  static unsigned int find_any_sec(const struct load_info *info, const char *name)
220  {
221  	unsigned int i;
222  
223  	for (i = 1; i < info->hdr->e_shnum; i++) {
224  		Elf_Shdr *shdr = &info->sechdrs[i];
225  		if (strcmp(info->secstrings + shdr->sh_name, name) == 0)
226  			return i;
227  	}
228  	return 0;
229  }
230  
231  /*
232   * Find a module section, or NULL. Fill in number of "objects" in section.
233   * Ignores SHF_ALLOC flag.
234   */
any_section_objs(const struct load_info * info,const char * name,size_t object_size,unsigned int * num)235  static __maybe_unused void *any_section_objs(const struct load_info *info,
236  					     const char *name,
237  					     size_t object_size,
238  					     unsigned int *num)
239  {
240  	unsigned int sec = find_any_sec(info, name);
241  
242  	/* Section 0 has sh_addr 0 and sh_size 0. */
243  	*num = info->sechdrs[sec].sh_size / object_size;
244  	return (void *)info->sechdrs[sec].sh_addr;
245  }
246  
247  #ifndef CONFIG_MODVERSIONS
248  #define symversion(base, idx) NULL
249  #else
250  #define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
251  #endif
252  
kernel_symbol_name(const struct kernel_symbol * sym)253  static const char *kernel_symbol_name(const struct kernel_symbol *sym)
254  {
255  #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
256  	return offset_to_ptr(&sym->name_offset);
257  #else
258  	return sym->name;
259  #endif
260  }
261  
kernel_symbol_namespace(const struct kernel_symbol * sym)262  static const char *kernel_symbol_namespace(const struct kernel_symbol *sym)
263  {
264  #ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
265  	if (!sym->namespace_offset)
266  		return NULL;
267  	return offset_to_ptr(&sym->namespace_offset);
268  #else
269  	return sym->namespace;
270  #endif
271  }
272  
cmp_name(const void * name,const void * sym)273  int cmp_name(const void *name, const void *sym)
274  {
275  	return strcmp(name, kernel_symbol_name(sym));
276  }
277  
find_exported_symbol_in_section(const struct symsearch * syms,struct module * owner,struct find_symbol_arg * fsa)278  static bool find_exported_symbol_in_section(const struct symsearch *syms,
279  					    struct module *owner,
280  					    struct find_symbol_arg *fsa)
281  {
282  	struct kernel_symbol *sym;
283  
284  	if (!fsa->gplok && syms->license == GPL_ONLY)
285  		return false;
286  
287  	sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
288  			sizeof(struct kernel_symbol), cmp_name);
289  	if (!sym)
290  		return false;
291  
292  	fsa->owner = owner;
293  	fsa->crc = symversion(syms->crcs, sym - syms->start);
294  	fsa->sym = sym;
295  	fsa->license = syms->license;
296  
297  	return true;
298  }
299  
300  /*
301   * Find an exported symbol and return it, along with, (optional) crc and
302   * (optional) module which owns it.  Needs preempt disabled or module_mutex.
303   */
find_symbol(struct find_symbol_arg * fsa)304  bool find_symbol(struct find_symbol_arg *fsa)
305  {
306  	static const struct symsearch arr[] = {
307  		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
308  		  NOT_GPL_ONLY },
309  		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
310  		  __start___kcrctab_gpl,
311  		  GPL_ONLY },
312  	};
313  	struct module *mod;
314  	unsigned int i;
315  
316  	module_assert_mutex_or_preempt();
317  
318  	for (i = 0; i < ARRAY_SIZE(arr); i++)
319  		if (find_exported_symbol_in_section(&arr[i], NULL, fsa))
320  			return true;
321  
322  	list_for_each_entry_rcu(mod, &modules, list,
323  				lockdep_is_held(&module_mutex)) {
324  		struct symsearch arr[] = {
325  			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
326  			  NOT_GPL_ONLY },
327  			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
328  			  mod->gpl_crcs,
329  			  GPL_ONLY },
330  		};
331  
332  		if (mod->state == MODULE_STATE_UNFORMED)
333  			continue;
334  
335  		for (i = 0; i < ARRAY_SIZE(arr); i++)
336  			if (find_exported_symbol_in_section(&arr[i], mod, fsa))
337  				return true;
338  	}
339  
340  	pr_debug("Failed to find symbol %s\n", fsa->name);
341  	return false;
342  }
343  
344  /*
345   * Search for module by name: must hold module_mutex (or preempt disabled
346   * for read-only access).
347   */
find_module_all(const char * name,size_t len,bool even_unformed)348  struct module *find_module_all(const char *name, size_t len,
349  			       bool even_unformed)
350  {
351  	struct module *mod;
352  
353  	module_assert_mutex_or_preempt();
354  
355  	list_for_each_entry_rcu(mod, &modules, list,
356  				lockdep_is_held(&module_mutex)) {
357  		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
358  			continue;
359  		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
360  			return mod;
361  	}
362  	return NULL;
363  }
364  
find_module(const char * name)365  struct module *find_module(const char *name)
366  {
367  	return find_module_all(name, strlen(name), false);
368  }
369  
370  #ifdef CONFIG_SMP
371  
mod_percpu(struct module * mod)372  static inline void __percpu *mod_percpu(struct module *mod)
373  {
374  	return mod->percpu;
375  }
376  
percpu_modalloc(struct module * mod,struct load_info * info)377  static int percpu_modalloc(struct module *mod, struct load_info *info)
378  {
379  	Elf_Shdr *pcpusec = &info->sechdrs[info->index.pcpu];
380  	unsigned long align = pcpusec->sh_addralign;
381  
382  	if (!pcpusec->sh_size)
383  		return 0;
384  
385  	if (align > PAGE_SIZE) {
386  		pr_warn("%s: per-cpu alignment %li > %li\n",
387  			mod->name, align, PAGE_SIZE);
388  		align = PAGE_SIZE;
389  	}
390  
391  	mod->percpu = __alloc_reserved_percpu(pcpusec->sh_size, align);
392  	if (!mod->percpu) {
393  		pr_warn("%s: Could not allocate %lu bytes percpu data\n",
394  			mod->name, (unsigned long)pcpusec->sh_size);
395  		return -ENOMEM;
396  	}
397  	mod->percpu_size = pcpusec->sh_size;
398  	return 0;
399  }
400  
percpu_modfree(struct module * mod)401  static void percpu_modfree(struct module *mod)
402  {
403  	free_percpu(mod->percpu);
404  }
405  
find_pcpusec(struct load_info * info)406  static unsigned int find_pcpusec(struct load_info *info)
407  {
408  	return find_sec(info, ".data..percpu");
409  }
410  
percpu_modcopy(struct module * mod,const void * from,unsigned long size)411  static void percpu_modcopy(struct module *mod,
412  			   const void *from, unsigned long size)
413  {
414  	int cpu;
415  
416  	for_each_possible_cpu(cpu)
417  		memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
418  }
419  
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)420  bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
421  {
422  	struct module *mod;
423  	unsigned int cpu;
424  
425  	preempt_disable();
426  
427  	list_for_each_entry_rcu(mod, &modules, list) {
428  		if (mod->state == MODULE_STATE_UNFORMED)
429  			continue;
430  		if (!mod->percpu_size)
431  			continue;
432  		for_each_possible_cpu(cpu) {
433  			void *start = per_cpu_ptr(mod->percpu, cpu);
434  			void *va = (void *)addr;
435  
436  			if (va >= start && va < start + mod->percpu_size) {
437  				if (can_addr) {
438  					*can_addr = (unsigned long) (va - start);
439  					*can_addr += (unsigned long)
440  						per_cpu_ptr(mod->percpu,
441  							    get_boot_cpu_id());
442  				}
443  				preempt_enable();
444  				return true;
445  			}
446  		}
447  	}
448  
449  	preempt_enable();
450  	return false;
451  }
452  
453  /**
454   * is_module_percpu_address() - test whether address is from module static percpu
455   * @addr: address to test
456   *
457   * Test whether @addr belongs to module static percpu area.
458   *
459   * Return: %true if @addr is from module static percpu area
460   */
is_module_percpu_address(unsigned long addr)461  bool is_module_percpu_address(unsigned long addr)
462  {
463  	return __is_module_percpu_address(addr, NULL);
464  }
465  
466  #else /* ... !CONFIG_SMP */
467  
mod_percpu(struct module * mod)468  static inline void __percpu *mod_percpu(struct module *mod)
469  {
470  	return NULL;
471  }
percpu_modalloc(struct module * mod,struct load_info * info)472  static int percpu_modalloc(struct module *mod, struct load_info *info)
473  {
474  	/* UP modules shouldn't have this section: ENOMEM isn't quite right */
475  	if (info->sechdrs[info->index.pcpu].sh_size != 0)
476  		return -ENOMEM;
477  	return 0;
478  }
percpu_modfree(struct module * mod)479  static inline void percpu_modfree(struct module *mod)
480  {
481  }
find_pcpusec(struct load_info * info)482  static unsigned int find_pcpusec(struct load_info *info)
483  {
484  	return 0;
485  }
percpu_modcopy(struct module * mod,const void * from,unsigned long size)486  static inline void percpu_modcopy(struct module *mod,
487  				  const void *from, unsigned long size)
488  {
489  	/* pcpusec should be 0, and size of that section should be 0. */
490  	BUG_ON(size != 0);
491  }
is_module_percpu_address(unsigned long addr)492  bool is_module_percpu_address(unsigned long addr)
493  {
494  	return false;
495  }
496  
__is_module_percpu_address(unsigned long addr,unsigned long * can_addr)497  bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
498  {
499  	return false;
500  }
501  
502  #endif /* CONFIG_SMP */
503  
504  #define MODINFO_ATTR(field)	\
505  static void setup_modinfo_##field(struct module *mod, const char *s)  \
506  {                                                                     \
507  	mod->field = kstrdup(s, GFP_KERNEL);                          \
508  }                                                                     \
509  static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
510  			struct module_kobject *mk, char *buffer)      \
511  {                                                                     \
512  	return scnprintf(buffer, PAGE_SIZE, "%s\n", mk->mod->field);  \
513  }                                                                     \
514  static int modinfo_##field##_exists(struct module *mod)               \
515  {                                                                     \
516  	return mod->field != NULL;                                    \
517  }                                                                     \
518  static void free_modinfo_##field(struct module *mod)                  \
519  {                                                                     \
520  	kfree(mod->field);                                            \
521  	mod->field = NULL;                                            \
522  }                                                                     \
523  static struct module_attribute modinfo_##field = {                    \
524  	.attr = { .name = __stringify(field), .mode = 0444 },         \
525  	.show = show_modinfo_##field,                                 \
526  	.setup = setup_modinfo_##field,                               \
527  	.test = modinfo_##field##_exists,                             \
528  	.free = free_modinfo_##field,                                 \
529  };
530  
531  MODINFO_ATTR(version);
532  MODINFO_ATTR(srcversion);
533  
534  static struct {
535  	char name[MODULE_NAME_LEN + 1];
536  	char taints[MODULE_FLAGS_BUF_SIZE];
537  } last_unloaded_module;
538  
539  #ifdef CONFIG_MODULE_UNLOAD
540  
541  EXPORT_TRACEPOINT_SYMBOL(module_get);
542  
543  /* MODULE_REF_BASE is the base reference count by kmodule loader. */
544  #define MODULE_REF_BASE	1
545  
546  /* Init the unload section of the module. */
module_unload_init(struct module * mod)547  static int module_unload_init(struct module *mod)
548  {
549  	/*
550  	 * Initialize reference counter to MODULE_REF_BASE.
551  	 * refcnt == 0 means module is going.
552  	 */
553  	atomic_set(&mod->refcnt, MODULE_REF_BASE);
554  
555  	INIT_LIST_HEAD(&mod->source_list);
556  	INIT_LIST_HEAD(&mod->target_list);
557  
558  	/* Hold reference count during initialization. */
559  	atomic_inc(&mod->refcnt);
560  
561  	return 0;
562  }
563  
564  /* Does a already use b? */
already_uses(struct module * a,struct module * b)565  static int already_uses(struct module *a, struct module *b)
566  {
567  	struct module_use *use;
568  
569  	list_for_each_entry(use, &b->source_list, source_list) {
570  		if (use->source == a)
571  			return 1;
572  	}
573  	pr_debug("%s does not use %s!\n", a->name, b->name);
574  	return 0;
575  }
576  
577  /*
578   * Module a uses b
579   *  - we add 'a' as a "source", 'b' as a "target" of module use
580   *  - the module_use is added to the list of 'b' sources (so
581   *    'b' can walk the list to see who sourced them), and of 'a'
582   *    targets (so 'a' can see what modules it targets).
583   */
add_module_usage(struct module * a,struct module * b)584  static int add_module_usage(struct module *a, struct module *b)
585  {
586  	struct module_use *use;
587  
588  	pr_debug("Allocating new usage for %s.\n", a->name);
589  	use = kmalloc(sizeof(*use), GFP_ATOMIC);
590  	if (!use)
591  		return -ENOMEM;
592  
593  	use->source = a;
594  	use->target = b;
595  	list_add(&use->source_list, &b->source_list);
596  	list_add(&use->target_list, &a->target_list);
597  	return 0;
598  }
599  
600  /* Module a uses b: caller needs module_mutex() */
ref_module(struct module * a,struct module * b)601  static int ref_module(struct module *a, struct module *b)
602  {
603  	int err;
604  
605  	if (b == NULL || already_uses(a, b))
606  		return 0;
607  
608  	/* If module isn't available, we fail. */
609  	err = strong_try_module_get(b);
610  	if (err)
611  		return err;
612  
613  	err = add_module_usage(a, b);
614  	if (err) {
615  		module_put(b);
616  		return err;
617  	}
618  	return 0;
619  }
620  
621  /* Clear the unload stuff of the module. */
module_unload_free(struct module * mod)622  static void module_unload_free(struct module *mod)
623  {
624  	struct module_use *use, *tmp;
625  
626  	mutex_lock(&module_mutex);
627  	list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
628  		struct module *i = use->target;
629  		pr_debug("%s unusing %s\n", mod->name, i->name);
630  		module_put(i);
631  		list_del(&use->source_list);
632  		list_del(&use->target_list);
633  		kfree(use);
634  	}
635  	mutex_unlock(&module_mutex);
636  }
637  
638  #ifdef CONFIG_MODULE_FORCE_UNLOAD
try_force_unload(unsigned int flags)639  static inline int try_force_unload(unsigned int flags)
640  {
641  	int ret = (flags & O_TRUNC);
642  	if (ret)
643  		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
644  	return ret;
645  }
646  #else
try_force_unload(unsigned int flags)647  static inline int try_force_unload(unsigned int flags)
648  {
649  	return 0;
650  }
651  #endif /* CONFIG_MODULE_FORCE_UNLOAD */
652  
653  /* Try to release refcount of module, 0 means success. */
try_release_module_ref(struct module * mod)654  static int try_release_module_ref(struct module *mod)
655  {
656  	int ret;
657  
658  	/* Try to decrement refcnt which we set at loading */
659  	ret = atomic_sub_return(MODULE_REF_BASE, &mod->refcnt);
660  	BUG_ON(ret < 0);
661  	if (ret)
662  		/* Someone can put this right now, recover with checking */
663  		ret = atomic_add_unless(&mod->refcnt, MODULE_REF_BASE, 0);
664  
665  	return ret;
666  }
667  
try_stop_module(struct module * mod,int flags,int * forced)668  static int try_stop_module(struct module *mod, int flags, int *forced)
669  {
670  	/* If it's not unused, quit unless we're forcing. */
671  	if (try_release_module_ref(mod) != 0) {
672  		*forced = try_force_unload(flags);
673  		if (!(*forced))
674  			return -EWOULDBLOCK;
675  	}
676  
677  	/* Mark it as dying. */
678  	mod->state = MODULE_STATE_GOING;
679  
680  	return 0;
681  }
682  
683  /**
684   * module_refcount() - return the refcount or -1 if unloading
685   * @mod:	the module we're checking
686   *
687   * Return:
688   *	-1 if the module is in the process of unloading
689   *	otherwise the number of references in the kernel to the module
690   */
module_refcount(struct module * mod)691  int module_refcount(struct module *mod)
692  {
693  	return atomic_read(&mod->refcnt) - MODULE_REF_BASE;
694  }
695  EXPORT_SYMBOL(module_refcount);
696  
697  /* This exists whether we can unload or not */
698  static void free_module(struct module *mod);
699  
SYSCALL_DEFINE2(delete_module,const char __user *,name_user,unsigned int,flags)700  SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
701  		unsigned int, flags)
702  {
703  	struct module *mod;
704  	char name[MODULE_NAME_LEN];
705  	char buf[MODULE_FLAGS_BUF_SIZE];
706  	int ret, forced = 0;
707  
708  	if (!capable(CAP_SYS_MODULE) || modules_disabled)
709  		return -EPERM;
710  
711  	if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
712  		return -EFAULT;
713  	name[MODULE_NAME_LEN-1] = '\0';
714  
715  	audit_log_kern_module(name);
716  
717  	if (mutex_lock_interruptible(&module_mutex) != 0)
718  		return -EINTR;
719  
720  	mod = find_module(name);
721  	if (!mod) {
722  		ret = -ENOENT;
723  		goto out;
724  	}
725  
726  	if (!list_empty(&mod->source_list)) {
727  		/* Other modules depend on us: get rid of them first. */
728  		ret = -EWOULDBLOCK;
729  		goto out;
730  	}
731  
732  	/* Doing init or already dying? */
733  	if (mod->state != MODULE_STATE_LIVE) {
734  		/* FIXME: if (force), slam module count damn the torpedoes */
735  		pr_debug("%s already dying\n", mod->name);
736  		ret = -EBUSY;
737  		goto out;
738  	}
739  
740  	/* If it has an init func, it must have an exit func to unload */
741  	if (mod->init && !mod->exit) {
742  		forced = try_force_unload(flags);
743  		if (!forced) {
744  			/* This module can't be removed */
745  			ret = -EBUSY;
746  			goto out;
747  		}
748  	}
749  
750  	ret = try_stop_module(mod, flags, &forced);
751  	if (ret != 0)
752  		goto out;
753  
754  	mutex_unlock(&module_mutex);
755  	/* Final destruction now no one is using it. */
756  	if (mod->exit != NULL)
757  		mod->exit();
758  	blocking_notifier_call_chain(&module_notify_list,
759  				     MODULE_STATE_GOING, mod);
760  	klp_module_going(mod);
761  	ftrace_release_mod(mod);
762  
763  	async_synchronize_full();
764  
765  	/* Store the name and taints of the last unloaded module for diagnostic purposes */
766  	strscpy(last_unloaded_module.name, mod->name, sizeof(last_unloaded_module.name));
767  	strscpy(last_unloaded_module.taints, module_flags(mod, buf, false), sizeof(last_unloaded_module.taints));
768  
769  	free_module(mod);
770  	/* someone could wait for the module in add_unformed_module() */
771  	wake_up_all(&module_wq);
772  	return 0;
773  out:
774  	mutex_unlock(&module_mutex);
775  	return ret;
776  }
777  
__symbol_put(const char * symbol)778  void __symbol_put(const char *symbol)
779  {
780  	struct find_symbol_arg fsa = {
781  		.name	= symbol,
782  		.gplok	= true,
783  	};
784  
785  	preempt_disable();
786  	BUG_ON(!find_symbol(&fsa));
787  	module_put(fsa.owner);
788  	preempt_enable();
789  }
790  EXPORT_SYMBOL(__symbol_put);
791  
792  /* Note this assumes addr is a function, which it currently always is. */
symbol_put_addr(void * addr)793  void symbol_put_addr(void *addr)
794  {
795  	struct module *modaddr;
796  	unsigned long a = (unsigned long)dereference_function_descriptor(addr);
797  
798  	if (core_kernel_text(a))
799  		return;
800  
801  	/*
802  	 * Even though we hold a reference on the module; we still need to
803  	 * disable preemption in order to safely traverse the data structure.
804  	 */
805  	preempt_disable();
806  	modaddr = __module_text_address(a);
807  	BUG_ON(!modaddr);
808  	module_put(modaddr);
809  	preempt_enable();
810  }
811  EXPORT_SYMBOL_GPL(symbol_put_addr);
812  
show_refcnt(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)813  static ssize_t show_refcnt(struct module_attribute *mattr,
814  			   struct module_kobject *mk, char *buffer)
815  {
816  	return sprintf(buffer, "%i\n", module_refcount(mk->mod));
817  }
818  
819  static struct module_attribute modinfo_refcnt =
820  	__ATTR(refcnt, 0444, show_refcnt, NULL);
821  
__module_get(struct module * module)822  void __module_get(struct module *module)
823  {
824  	if (module) {
825  		atomic_inc(&module->refcnt);
826  		trace_module_get(module, _RET_IP_);
827  	}
828  }
829  EXPORT_SYMBOL(__module_get);
830  
try_module_get(struct module * module)831  bool try_module_get(struct module *module)
832  {
833  	bool ret = true;
834  
835  	if (module) {
836  		/* Note: here, we can fail to get a reference */
837  		if (likely(module_is_live(module) &&
838  			   atomic_inc_not_zero(&module->refcnt) != 0))
839  			trace_module_get(module, _RET_IP_);
840  		else
841  			ret = false;
842  	}
843  	return ret;
844  }
845  EXPORT_SYMBOL(try_module_get);
846  
module_put(struct module * module)847  void module_put(struct module *module)
848  {
849  	int ret;
850  
851  	if (module) {
852  		ret = atomic_dec_if_positive(&module->refcnt);
853  		WARN_ON(ret < 0);	/* Failed to put refcount */
854  		trace_module_put(module, _RET_IP_);
855  	}
856  }
857  EXPORT_SYMBOL(module_put);
858  
859  #else /* !CONFIG_MODULE_UNLOAD */
module_unload_free(struct module * mod)860  static inline void module_unload_free(struct module *mod)
861  {
862  }
863  
ref_module(struct module * a,struct module * b)864  static int ref_module(struct module *a, struct module *b)
865  {
866  	return strong_try_module_get(b);
867  }
868  
module_unload_init(struct module * mod)869  static inline int module_unload_init(struct module *mod)
870  {
871  	return 0;
872  }
873  #endif /* CONFIG_MODULE_UNLOAD */
874  
module_flags_taint(unsigned long taints,char * buf)875  size_t module_flags_taint(unsigned long taints, char *buf)
876  {
877  	size_t l = 0;
878  	int i;
879  
880  	for (i = 0; i < TAINT_FLAGS_COUNT; i++) {
881  		if (taint_flags[i].module && test_bit(i, &taints))
882  			buf[l++] = taint_flags[i].c_true;
883  	}
884  
885  	return l;
886  }
887  
show_initstate(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)888  static ssize_t show_initstate(struct module_attribute *mattr,
889  			      struct module_kobject *mk, char *buffer)
890  {
891  	const char *state = "unknown";
892  
893  	switch (mk->mod->state) {
894  	case MODULE_STATE_LIVE:
895  		state = "live";
896  		break;
897  	case MODULE_STATE_COMING:
898  		state = "coming";
899  		break;
900  	case MODULE_STATE_GOING:
901  		state = "going";
902  		break;
903  	default:
904  		BUG();
905  	}
906  	return sprintf(buffer, "%s\n", state);
907  }
908  
909  static struct module_attribute modinfo_initstate =
910  	__ATTR(initstate, 0444, show_initstate, NULL);
911  
store_uevent(struct module_attribute * mattr,struct module_kobject * mk,const char * buffer,size_t count)912  static ssize_t store_uevent(struct module_attribute *mattr,
913  			    struct module_kobject *mk,
914  			    const char *buffer, size_t count)
915  {
916  	int rc;
917  
918  	rc = kobject_synth_uevent(&mk->kobj, buffer, count);
919  	return rc ? rc : count;
920  }
921  
922  struct module_attribute module_uevent =
923  	__ATTR(uevent, 0200, NULL, store_uevent);
924  
show_coresize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)925  static ssize_t show_coresize(struct module_attribute *mattr,
926  			     struct module_kobject *mk, char *buffer)
927  {
928  	unsigned int size = mk->mod->mem[MOD_TEXT].size;
929  
930  	if (!IS_ENABLED(CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC)) {
931  		for_class_mod_mem_type(type, core_data)
932  			size += mk->mod->mem[type].size;
933  	}
934  	return sprintf(buffer, "%u\n", size);
935  }
936  
937  static struct module_attribute modinfo_coresize =
938  	__ATTR(coresize, 0444, show_coresize, NULL);
939  
940  #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
show_datasize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)941  static ssize_t show_datasize(struct module_attribute *mattr,
942  			     struct module_kobject *mk, char *buffer)
943  {
944  	unsigned int size = 0;
945  
946  	for_class_mod_mem_type(type, core_data)
947  		size += mk->mod->mem[type].size;
948  	return sprintf(buffer, "%u\n", size);
949  }
950  
951  static struct module_attribute modinfo_datasize =
952  	__ATTR(datasize, 0444, show_datasize, NULL);
953  #endif
954  
show_initsize(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)955  static ssize_t show_initsize(struct module_attribute *mattr,
956  			     struct module_kobject *mk, char *buffer)
957  {
958  	unsigned int size = 0;
959  
960  	for_class_mod_mem_type(type, init)
961  		size += mk->mod->mem[type].size;
962  	return sprintf(buffer, "%u\n", size);
963  }
964  
965  static struct module_attribute modinfo_initsize =
966  	__ATTR(initsize, 0444, show_initsize, NULL);
967  
show_taint(struct module_attribute * mattr,struct module_kobject * mk,char * buffer)968  static ssize_t show_taint(struct module_attribute *mattr,
969  			  struct module_kobject *mk, char *buffer)
970  {
971  	size_t l;
972  
973  	l = module_flags_taint(mk->mod->taints, buffer);
974  	buffer[l++] = '\n';
975  	return l;
976  }
977  
978  static struct module_attribute modinfo_taint =
979  	__ATTR(taint, 0444, show_taint, NULL);
980  
981  struct module_attribute *modinfo_attrs[] = {
982  	&module_uevent,
983  	&modinfo_version,
984  	&modinfo_srcversion,
985  	&modinfo_initstate,
986  	&modinfo_coresize,
987  #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
988  	&modinfo_datasize,
989  #endif
990  	&modinfo_initsize,
991  	&modinfo_taint,
992  #ifdef CONFIG_MODULE_UNLOAD
993  	&modinfo_refcnt,
994  #endif
995  	NULL,
996  };
997  
998  size_t modinfo_attrs_count = ARRAY_SIZE(modinfo_attrs);
999  
1000  static const char vermagic[] = VERMAGIC_STRING;
1001  
try_to_force_load(struct module * mod,const char * reason)1002  int try_to_force_load(struct module *mod, const char *reason)
1003  {
1004  #ifdef CONFIG_MODULE_FORCE_LOAD
1005  	if (!test_taint(TAINT_FORCED_MODULE))
1006  		pr_warn("%s: %s: kernel tainted.\n", mod->name, reason);
1007  	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
1008  	return 0;
1009  #else
1010  	return -ENOEXEC;
1011  #endif
1012  }
1013  
1014  /* Parse tag=value strings from .modinfo section */
module_next_tag_pair(char * string,unsigned long * secsize)1015  char *module_next_tag_pair(char *string, unsigned long *secsize)
1016  {
1017  	/* Skip non-zero chars */
1018  	while (string[0]) {
1019  		string++;
1020  		if ((*secsize)-- <= 1)
1021  			return NULL;
1022  	}
1023  
1024  	/* Skip any zero padding. */
1025  	while (!string[0]) {
1026  		string++;
1027  		if ((*secsize)-- <= 1)
1028  			return NULL;
1029  	}
1030  	return string;
1031  }
1032  
get_next_modinfo(const struct load_info * info,const char * tag,char * prev)1033  static char *get_next_modinfo(const struct load_info *info, const char *tag,
1034  			      char *prev)
1035  {
1036  	char *p;
1037  	unsigned int taglen = strlen(tag);
1038  	Elf_Shdr *infosec = &info->sechdrs[info->index.info];
1039  	unsigned long size = infosec->sh_size;
1040  
1041  	/*
1042  	 * get_modinfo() calls made before rewrite_section_headers()
1043  	 * must use sh_offset, as sh_addr isn't set!
1044  	 */
1045  	char *modinfo = (char *)info->hdr + infosec->sh_offset;
1046  
1047  	if (prev) {
1048  		size -= prev - modinfo;
1049  		modinfo = module_next_tag_pair(prev, &size);
1050  	}
1051  
1052  	for (p = modinfo; p; p = module_next_tag_pair(p, &size)) {
1053  		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
1054  			return p + taglen + 1;
1055  	}
1056  	return NULL;
1057  }
1058  
get_modinfo(const struct load_info * info,const char * tag)1059  static char *get_modinfo(const struct load_info *info, const char *tag)
1060  {
1061  	return get_next_modinfo(info, tag, NULL);
1062  }
1063  
verify_namespace_is_imported(const struct load_info * info,const struct kernel_symbol * sym,struct module * mod)1064  static int verify_namespace_is_imported(const struct load_info *info,
1065  					const struct kernel_symbol *sym,
1066  					struct module *mod)
1067  {
1068  	const char *namespace;
1069  	char *imported_namespace;
1070  
1071  	namespace = kernel_symbol_namespace(sym);
1072  	if (namespace && namespace[0]) {
1073  		for_each_modinfo_entry(imported_namespace, info, "import_ns") {
1074  			if (strcmp(namespace, imported_namespace) == 0)
1075  				return 0;
1076  		}
1077  #ifdef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1078  		pr_warn(
1079  #else
1080  		pr_err(
1081  #endif
1082  			"%s: module uses symbol (%s) from namespace %s, but does not import it.\n",
1083  			mod->name, kernel_symbol_name(sym), namespace);
1084  #ifndef CONFIG_MODULE_ALLOW_MISSING_NAMESPACE_IMPORTS
1085  		return -EINVAL;
1086  #endif
1087  	}
1088  	return 0;
1089  }
1090  
inherit_taint(struct module * mod,struct module * owner,const char * name)1091  static bool inherit_taint(struct module *mod, struct module *owner, const char *name)
1092  {
1093  	if (!owner || !test_bit(TAINT_PROPRIETARY_MODULE, &owner->taints))
1094  		return true;
1095  
1096  	if (mod->using_gplonly_symbols) {
1097  		pr_err("%s: module using GPL-only symbols uses symbols %s from proprietary module %s.\n",
1098  			mod->name, name, owner->name);
1099  		return false;
1100  	}
1101  
1102  	if (!test_bit(TAINT_PROPRIETARY_MODULE, &mod->taints)) {
1103  		pr_warn("%s: module uses symbols %s from proprietary module %s, inheriting taint.\n",
1104  			mod->name, name, owner->name);
1105  		set_bit(TAINT_PROPRIETARY_MODULE, &mod->taints);
1106  	}
1107  	return true;
1108  }
1109  
1110  /* 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[])1111  static const struct kernel_symbol *resolve_symbol(struct module *mod,
1112  						  const struct load_info *info,
1113  						  const char *name,
1114  						  char ownername[])
1115  {
1116  	struct find_symbol_arg fsa = {
1117  		.name	= name,
1118  		.gplok	= !(mod->taints & (1 << TAINT_PROPRIETARY_MODULE)),
1119  		.warn	= true,
1120  	};
1121  	int err;
1122  
1123  	/*
1124  	 * The module_mutex should not be a heavily contended lock;
1125  	 * if we get the occasional sleep here, we'll go an extra iteration
1126  	 * in the wait_event_interruptible(), which is harmless.
1127  	 */
1128  	sched_annotate_sleep();
1129  	mutex_lock(&module_mutex);
1130  	if (!find_symbol(&fsa))
1131  		goto unlock;
1132  
1133  	if (fsa.license == GPL_ONLY)
1134  		mod->using_gplonly_symbols = true;
1135  
1136  	if (!inherit_taint(mod, fsa.owner, name)) {
1137  		fsa.sym = NULL;
1138  		goto getname;
1139  	}
1140  
1141  	if (!check_version(info, name, mod, fsa.crc)) {
1142  		fsa.sym = ERR_PTR(-EINVAL);
1143  		goto getname;
1144  	}
1145  
1146  	err = verify_namespace_is_imported(info, fsa.sym, mod);
1147  	if (err) {
1148  		fsa.sym = ERR_PTR(err);
1149  		goto getname;
1150  	}
1151  
1152  	err = ref_module(mod, fsa.owner);
1153  	if (err) {
1154  		fsa.sym = ERR_PTR(err);
1155  		goto getname;
1156  	}
1157  
1158  getname:
1159  	/* We must make copy under the lock if we failed to get ref. */
1160  	strncpy(ownername, module_name(fsa.owner), MODULE_NAME_LEN);
1161  unlock:
1162  	mutex_unlock(&module_mutex);
1163  	return fsa.sym;
1164  }
1165  
1166  static const struct kernel_symbol *
resolve_symbol_wait(struct module * mod,const struct load_info * info,const char * name)1167  resolve_symbol_wait(struct module *mod,
1168  		    const struct load_info *info,
1169  		    const char *name)
1170  {
1171  	const struct kernel_symbol *ksym;
1172  	char owner[MODULE_NAME_LEN];
1173  
1174  	if (wait_event_interruptible_timeout(module_wq,
1175  			!IS_ERR(ksym = resolve_symbol(mod, info, name, owner))
1176  			|| PTR_ERR(ksym) != -EBUSY,
1177  					     30 * HZ) <= 0) {
1178  		pr_warn("%s: gave up waiting for init of module %s.\n",
1179  			mod->name, owner);
1180  	}
1181  	return ksym;
1182  }
1183  
module_arch_cleanup(struct module * mod)1184  void __weak module_arch_cleanup(struct module *mod)
1185  {
1186  }
1187  
module_arch_freeing_init(struct module * mod)1188  void __weak module_arch_freeing_init(struct module *mod)
1189  {
1190  }
1191  
module_memory_alloc(struct module * mod,enum mod_mem_type type)1192  static int module_memory_alloc(struct module *mod, enum mod_mem_type type)
1193  {
1194  	unsigned int size = PAGE_ALIGN(mod->mem[type].size);
1195  	enum execmem_type execmem_type;
1196  	void *ptr;
1197  
1198  	mod->mem[type].size = size;
1199  
1200  	if (mod_mem_type_is_data(type))
1201  		execmem_type = EXECMEM_MODULE_DATA;
1202  	else
1203  		execmem_type = EXECMEM_MODULE_TEXT;
1204  
1205  	ptr = execmem_alloc(execmem_type, size);
1206  	if (!ptr)
1207  		return -ENOMEM;
1208  
1209  	/*
1210  	 * The pointer to these blocks of memory are stored on the module
1211  	 * structure and we keep that around so long as the module is
1212  	 * around. We only free that memory when we unload the module.
1213  	 * Just mark them as not being a leak then. The .init* ELF
1214  	 * sections *do* get freed after boot so we *could* treat them
1215  	 * slightly differently with kmemleak_ignore() and only grey
1216  	 * them out as they work as typical memory allocations which
1217  	 * *do* eventually get freed, but let's just keep things simple
1218  	 * and avoid *any* false positives.
1219  	 */
1220  	kmemleak_not_leak(ptr);
1221  
1222  	memset(ptr, 0, size);
1223  	mod->mem[type].base = ptr;
1224  
1225  	return 0;
1226  }
1227  
module_memory_free(struct module * mod,enum mod_mem_type type,bool unload_codetags)1228  static void module_memory_free(struct module *mod, enum mod_mem_type type,
1229  			       bool unload_codetags)
1230  {
1231  	void *ptr = mod->mem[type].base;
1232  
1233  	if (!unload_codetags && mod_mem_type_is_core_data(type))
1234  		return;
1235  
1236  	execmem_free(ptr);
1237  }
1238  
free_mod_mem(struct module * mod,bool unload_codetags)1239  static void free_mod_mem(struct module *mod, bool unload_codetags)
1240  {
1241  	for_each_mod_mem_type(type) {
1242  		struct module_memory *mod_mem = &mod->mem[type];
1243  
1244  		if (type == MOD_DATA)
1245  			continue;
1246  
1247  		/* Free lock-classes; relies on the preceding sync_rcu(). */
1248  		lockdep_free_key_range(mod_mem->base, mod_mem->size);
1249  		if (mod_mem->size)
1250  			module_memory_free(mod, type, unload_codetags);
1251  	}
1252  
1253  	/* MOD_DATA hosts mod, so free it at last */
1254  	lockdep_free_key_range(mod->mem[MOD_DATA].base, mod->mem[MOD_DATA].size);
1255  	module_memory_free(mod, MOD_DATA, unload_codetags);
1256  }
1257  
1258  /* Free a module, remove from lists, etc. */
free_module(struct module * mod)1259  static void free_module(struct module *mod)
1260  {
1261  	bool unload_codetags;
1262  
1263  	trace_module_free(mod);
1264  
1265  	unload_codetags = codetag_unload_module(mod);
1266  	if (!unload_codetags)
1267  		pr_warn("%s: memory allocation(s) from the module still alive, cannot unload cleanly\n",
1268  			mod->name);
1269  
1270  	mod_sysfs_teardown(mod);
1271  
1272  	/*
1273  	 * We leave it in list to prevent duplicate loads, but make sure
1274  	 * that noone uses it while it's being deconstructed.
1275  	 */
1276  	mutex_lock(&module_mutex);
1277  	mod->state = MODULE_STATE_UNFORMED;
1278  	mutex_unlock(&module_mutex);
1279  
1280  	/* Arch-specific cleanup. */
1281  	module_arch_cleanup(mod);
1282  
1283  	/* Module unload stuff */
1284  	module_unload_free(mod);
1285  
1286  	/* Free any allocated parameters. */
1287  	destroy_params(mod->kp, mod->num_kp);
1288  
1289  	if (is_livepatch_module(mod))
1290  		free_module_elf(mod);
1291  
1292  	/* Now we can delete it from the lists */
1293  	mutex_lock(&module_mutex);
1294  	/* Unlink carefully: kallsyms could be walking list. */
1295  	list_del_rcu(&mod->list);
1296  	mod_tree_remove(mod);
1297  	/* Remove this module from bug list, this uses list_del_rcu */
1298  	module_bug_cleanup(mod);
1299  	/* Wait for RCU-sched synchronizing before releasing mod->list and buglist. */
1300  	synchronize_rcu();
1301  	if (try_add_tainted_module(mod))
1302  		pr_err("%s: adding tainted module to the unloaded tainted modules list failed.\n",
1303  		       mod->name);
1304  	mutex_unlock(&module_mutex);
1305  
1306  	/* This may be empty, but that's OK */
1307  	module_arch_freeing_init(mod);
1308  	kfree(mod->args);
1309  	percpu_modfree(mod);
1310  
1311  	free_mod_mem(mod, unload_codetags);
1312  }
1313  
__symbol_get(const char * symbol)1314  void *__symbol_get(const char *symbol)
1315  {
1316  	struct find_symbol_arg fsa = {
1317  		.name	= symbol,
1318  		.gplok	= true,
1319  		.warn	= true,
1320  	};
1321  
1322  	preempt_disable();
1323  	if (!find_symbol(&fsa))
1324  		goto fail;
1325  	if (fsa.license != GPL_ONLY) {
1326  		pr_warn("failing symbol_get of non-GPLONLY symbol %s.\n",
1327  			symbol);
1328  		goto fail;
1329  	}
1330  	if (strong_try_module_get(fsa.owner))
1331  		goto fail;
1332  	preempt_enable();
1333  	return (void *)kernel_symbol_value(fsa.sym);
1334  fail:
1335  	preempt_enable();
1336  	return NULL;
1337  }
1338  EXPORT_SYMBOL_GPL(__symbol_get);
1339  
1340  /*
1341   * Ensure that an exported symbol [global namespace] does not already exist
1342   * in the kernel or in some other module's exported symbol table.
1343   *
1344   * You must hold the module_mutex.
1345   */
verify_exported_symbols(struct module * mod)1346  static int verify_exported_symbols(struct module *mod)
1347  {
1348  	unsigned int i;
1349  	const struct kernel_symbol *s;
1350  	struct {
1351  		const struct kernel_symbol *sym;
1352  		unsigned int num;
1353  	} arr[] = {
1354  		{ mod->syms, mod->num_syms },
1355  		{ mod->gpl_syms, mod->num_gpl_syms },
1356  	};
1357  
1358  	for (i = 0; i < ARRAY_SIZE(arr); i++) {
1359  		for (s = arr[i].sym; s < arr[i].sym + arr[i].num; s++) {
1360  			struct find_symbol_arg fsa = {
1361  				.name	= kernel_symbol_name(s),
1362  				.gplok	= true,
1363  			};
1364  			if (find_symbol(&fsa)) {
1365  				pr_err("%s: exports duplicate symbol %s"
1366  				       " (owned by %s)\n",
1367  				       mod->name, kernel_symbol_name(s),
1368  				       module_name(fsa.owner));
1369  				return -ENOEXEC;
1370  			}
1371  		}
1372  	}
1373  	return 0;
1374  }
1375  
ignore_undef_symbol(Elf_Half emachine,const char * name)1376  static bool ignore_undef_symbol(Elf_Half emachine, const char *name)
1377  {
1378  	/*
1379  	 * On x86, PIC code and Clang non-PIC code may have call foo@PLT. GNU as
1380  	 * before 2.37 produces an unreferenced _GLOBAL_OFFSET_TABLE_ on x86-64.
1381  	 * i386 has a similar problem but may not deserve a fix.
1382  	 *
1383  	 * If we ever have to ignore many symbols, consider refactoring the code to
1384  	 * only warn if referenced by a relocation.
1385  	 */
1386  	if (emachine == EM_386 || emachine == EM_X86_64)
1387  		return !strcmp(name, "_GLOBAL_OFFSET_TABLE_");
1388  	return false;
1389  }
1390  
1391  /* Change all symbols so that st_value encodes the pointer directly. */
simplify_symbols(struct module * mod,const struct load_info * info)1392  static int simplify_symbols(struct module *mod, const struct load_info *info)
1393  {
1394  	Elf_Shdr *symsec = &info->sechdrs[info->index.sym];
1395  	Elf_Sym *sym = (void *)symsec->sh_addr;
1396  	unsigned long secbase;
1397  	unsigned int i;
1398  	int ret = 0;
1399  	const struct kernel_symbol *ksym;
1400  
1401  	for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
1402  		const char *name = info->strtab + sym[i].st_name;
1403  
1404  		switch (sym[i].st_shndx) {
1405  		case SHN_COMMON:
1406  			/* Ignore common symbols */
1407  			if (!strncmp(name, "__gnu_lto", 9))
1408  				break;
1409  
1410  			/*
1411  			 * We compiled with -fno-common.  These are not
1412  			 * supposed to happen.
1413  			 */
1414  			pr_debug("Common symbol: %s\n", name);
1415  			pr_warn("%s: please compile with -fno-common\n",
1416  			       mod->name);
1417  			ret = -ENOEXEC;
1418  			break;
1419  
1420  		case SHN_ABS:
1421  			/* Don't need to do anything */
1422  			pr_debug("Absolute symbol: 0x%08lx %s\n",
1423  				 (long)sym[i].st_value, name);
1424  			break;
1425  
1426  		case SHN_LIVEPATCH:
1427  			/* Livepatch symbols are resolved by livepatch */
1428  			break;
1429  
1430  		case SHN_UNDEF:
1431  			ksym = resolve_symbol_wait(mod, info, name);
1432  			/* Ok if resolved.  */
1433  			if (ksym && !IS_ERR(ksym)) {
1434  				sym[i].st_value = kernel_symbol_value(ksym);
1435  				break;
1436  			}
1437  
1438  			/* Ok if weak or ignored.  */
1439  			if (!ksym &&
1440  			    (ELF_ST_BIND(sym[i].st_info) == STB_WEAK ||
1441  			     ignore_undef_symbol(info->hdr->e_machine, name)))
1442  				break;
1443  
1444  			ret = PTR_ERR(ksym) ?: -ENOENT;
1445  			pr_warn("%s: Unknown symbol %s (err %d)\n",
1446  				mod->name, name, ret);
1447  			break;
1448  
1449  		default:
1450  			/* Divert to percpu allocation if a percpu var. */
1451  			if (sym[i].st_shndx == info->index.pcpu)
1452  				secbase = (unsigned long)mod_percpu(mod);
1453  			else
1454  				secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
1455  			sym[i].st_value += secbase;
1456  			break;
1457  		}
1458  	}
1459  
1460  	return ret;
1461  }
1462  
apply_relocations(struct module * mod,const struct load_info * info)1463  static int apply_relocations(struct module *mod, const struct load_info *info)
1464  {
1465  	unsigned int i;
1466  	int err = 0;
1467  
1468  	/* Now do relocations. */
1469  	for (i = 1; i < info->hdr->e_shnum; i++) {
1470  		unsigned int infosec = info->sechdrs[i].sh_info;
1471  
1472  		/* Not a valid relocation section? */
1473  		if (infosec >= info->hdr->e_shnum)
1474  			continue;
1475  
1476  		/* Don't bother with non-allocated sections */
1477  		if (!(info->sechdrs[infosec].sh_flags & SHF_ALLOC))
1478  			continue;
1479  
1480  		if (info->sechdrs[i].sh_flags & SHF_RELA_LIVEPATCH)
1481  			err = klp_apply_section_relocs(mod, info->sechdrs,
1482  						       info->secstrings,
1483  						       info->strtab,
1484  						       info->index.sym, i,
1485  						       NULL);
1486  		else if (info->sechdrs[i].sh_type == SHT_REL)
1487  			err = apply_relocate(info->sechdrs, info->strtab,
1488  					     info->index.sym, i, mod);
1489  		else if (info->sechdrs[i].sh_type == SHT_RELA)
1490  			err = apply_relocate_add(info->sechdrs, info->strtab,
1491  						 info->index.sym, i, mod);
1492  		if (err < 0)
1493  			break;
1494  	}
1495  	return err;
1496  }
1497  
1498  /* Additional bytes needed by arch in front of individual sections */
arch_mod_section_prepend(struct module * mod,unsigned int section)1499  unsigned int __weak arch_mod_section_prepend(struct module *mod,
1500  					     unsigned int section)
1501  {
1502  	/* default implementation just returns zero */
1503  	return 0;
1504  }
1505  
module_get_offset_and_type(struct module * mod,enum mod_mem_type type,Elf_Shdr * sechdr,unsigned int section)1506  long module_get_offset_and_type(struct module *mod, enum mod_mem_type type,
1507  				Elf_Shdr *sechdr, unsigned int section)
1508  {
1509  	long offset;
1510  	long mask = ((unsigned long)(type) & SH_ENTSIZE_TYPE_MASK) << SH_ENTSIZE_TYPE_SHIFT;
1511  
1512  	mod->mem[type].size += arch_mod_section_prepend(mod, section);
1513  	offset = ALIGN(mod->mem[type].size, sechdr->sh_addralign ?: 1);
1514  	mod->mem[type].size = offset + sechdr->sh_size;
1515  
1516  	WARN_ON_ONCE(offset & mask);
1517  	return offset | mask;
1518  }
1519  
module_init_layout_section(const char * sname)1520  bool module_init_layout_section(const char *sname)
1521  {
1522  #ifndef CONFIG_MODULE_UNLOAD
1523  	if (module_exit_section(sname))
1524  		return true;
1525  #endif
1526  	return module_init_section(sname);
1527  }
1528  
__layout_sections(struct module * mod,struct load_info * info,bool is_init)1529  static void __layout_sections(struct module *mod, struct load_info *info, bool is_init)
1530  {
1531  	unsigned int m, i;
1532  
1533  	static const unsigned long masks[][2] = {
1534  		/*
1535  		 * NOTE: all executable code must be the first section
1536  		 * in this array; otherwise modify the text_size
1537  		 * finder in the two loops below
1538  		 */
1539  		{ SHF_EXECINSTR | SHF_ALLOC, ARCH_SHF_SMALL },
1540  		{ SHF_ALLOC, SHF_WRITE | ARCH_SHF_SMALL },
1541  		{ SHF_RO_AFTER_INIT | SHF_ALLOC, ARCH_SHF_SMALL },
1542  		{ SHF_WRITE | SHF_ALLOC, ARCH_SHF_SMALL },
1543  		{ ARCH_SHF_SMALL | SHF_ALLOC, 0 }
1544  	};
1545  	static const int core_m_to_mem_type[] = {
1546  		MOD_TEXT,
1547  		MOD_RODATA,
1548  		MOD_RO_AFTER_INIT,
1549  		MOD_DATA,
1550  		MOD_DATA,
1551  	};
1552  	static const int init_m_to_mem_type[] = {
1553  		MOD_INIT_TEXT,
1554  		MOD_INIT_RODATA,
1555  		MOD_INVALID,
1556  		MOD_INIT_DATA,
1557  		MOD_INIT_DATA,
1558  	};
1559  
1560  	for (m = 0; m < ARRAY_SIZE(masks); ++m) {
1561  		enum mod_mem_type type = is_init ? init_m_to_mem_type[m] : core_m_to_mem_type[m];
1562  
1563  		for (i = 0; i < info->hdr->e_shnum; ++i) {
1564  			Elf_Shdr *s = &info->sechdrs[i];
1565  			const char *sname = info->secstrings + s->sh_name;
1566  
1567  			if ((s->sh_flags & masks[m][0]) != masks[m][0]
1568  			    || (s->sh_flags & masks[m][1])
1569  			    || s->sh_entsize != ~0UL
1570  			    || is_init != module_init_layout_section(sname))
1571  				continue;
1572  
1573  			if (WARN_ON_ONCE(type == MOD_INVALID))
1574  				continue;
1575  
1576  			s->sh_entsize = module_get_offset_and_type(mod, type, s, i);
1577  			pr_debug("\t%s\n", sname);
1578  		}
1579  	}
1580  }
1581  
1582  /*
1583   * Lay out the SHF_ALLOC sections in a way not dissimilar to how ld
1584   * might -- code, read-only data, read-write data, small data.  Tally
1585   * sizes, and place the offsets into sh_entsize fields: high bit means it
1586   * belongs in init.
1587   */
layout_sections(struct module * mod,struct load_info * info)1588  static void layout_sections(struct module *mod, struct load_info *info)
1589  {
1590  	unsigned int i;
1591  
1592  	for (i = 0; i < info->hdr->e_shnum; i++)
1593  		info->sechdrs[i].sh_entsize = ~0UL;
1594  
1595  	pr_debug("Core section allocation order for %s:\n", mod->name);
1596  	__layout_sections(mod, info, false);
1597  
1598  	pr_debug("Init section allocation order for %s:\n", mod->name);
1599  	__layout_sections(mod, info, true);
1600  }
1601  
module_license_taint_check(struct module * mod,const char * license)1602  static void module_license_taint_check(struct module *mod, const char *license)
1603  {
1604  	if (!license)
1605  		license = "unspecified";
1606  
1607  	if (!license_is_gpl_compatible(license)) {
1608  		if (!test_taint(TAINT_PROPRIETARY_MODULE))
1609  			pr_warn("%s: module license '%s' taints kernel.\n",
1610  				mod->name, license);
1611  		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
1612  				 LOCKDEP_NOW_UNRELIABLE);
1613  	}
1614  }
1615  
setup_modinfo(struct module * mod,struct load_info * info)1616  static void setup_modinfo(struct module *mod, struct load_info *info)
1617  {
1618  	struct module_attribute *attr;
1619  	int i;
1620  
1621  	for (i = 0; (attr = modinfo_attrs[i]); i++) {
1622  		if (attr->setup)
1623  			attr->setup(mod, get_modinfo(info, attr->attr.name));
1624  	}
1625  }
1626  
free_modinfo(struct module * mod)1627  static void free_modinfo(struct module *mod)
1628  {
1629  	struct module_attribute *attr;
1630  	int i;
1631  
1632  	for (i = 0; (attr = modinfo_attrs[i]); i++) {
1633  		if (attr->free)
1634  			attr->free(mod);
1635  	}
1636  }
1637  
module_init_section(const char * name)1638  bool __weak module_init_section(const char *name)
1639  {
1640  	return strstarts(name, ".init");
1641  }
1642  
module_exit_section(const char * name)1643  bool __weak module_exit_section(const char *name)
1644  {
1645  	return strstarts(name, ".exit");
1646  }
1647  
validate_section_offset(struct load_info * info,Elf_Shdr * shdr)1648  static int validate_section_offset(struct load_info *info, Elf_Shdr *shdr)
1649  {
1650  #if defined(CONFIG_64BIT)
1651  	unsigned long long secend;
1652  #else
1653  	unsigned long secend;
1654  #endif
1655  
1656  	/*
1657  	 * Check for both overflow and offset/size being
1658  	 * too large.
1659  	 */
1660  	secend = shdr->sh_offset + shdr->sh_size;
1661  	if (secend < shdr->sh_offset || secend > info->len)
1662  		return -ENOEXEC;
1663  
1664  	return 0;
1665  }
1666  
1667  /*
1668   * Check userspace passed ELF module against our expectations, and cache
1669   * useful variables for further processing as we go.
1670   *
1671   * This does basic validity checks against section offsets and sizes, the
1672   * section name string table, and the indices used for it (sh_name).
1673   *
1674   * As a last step, since we're already checking the ELF sections we cache
1675   * useful variables which will be used later for our convenience:
1676   *
1677   * 	o pointers to section headers
1678   * 	o cache the modinfo symbol section
1679   * 	o cache the string symbol section
1680   * 	o cache the module section
1681   *
1682   * As a last step we set info->mod to the temporary copy of the module in
1683   * info->hdr. The final one will be allocated in move_module(). Any
1684   * modifications we make to our copy of the module will be carried over
1685   * to the final minted module.
1686   */
elf_validity_cache_copy(struct load_info * info,int flags)1687  static int elf_validity_cache_copy(struct load_info *info, int flags)
1688  {
1689  	unsigned int i;
1690  	Elf_Shdr *shdr, *strhdr;
1691  	int err;
1692  	unsigned int num_mod_secs = 0, mod_idx;
1693  	unsigned int num_info_secs = 0, info_idx;
1694  	unsigned int num_sym_secs = 0, sym_idx;
1695  
1696  	if (info->len < sizeof(*(info->hdr))) {
1697  		pr_err("Invalid ELF header len %lu\n", info->len);
1698  		goto no_exec;
1699  	}
1700  
1701  	if (memcmp(info->hdr->e_ident, ELFMAG, SELFMAG) != 0) {
1702  		pr_err("Invalid ELF header magic: != %s\n", ELFMAG);
1703  		goto no_exec;
1704  	}
1705  	if (info->hdr->e_type != ET_REL) {
1706  		pr_err("Invalid ELF header type: %u != %u\n",
1707  		       info->hdr->e_type, ET_REL);
1708  		goto no_exec;
1709  	}
1710  	if (!elf_check_arch(info->hdr)) {
1711  		pr_err("Invalid architecture in ELF header: %u\n",
1712  		       info->hdr->e_machine);
1713  		goto no_exec;
1714  	}
1715  	if (!module_elf_check_arch(info->hdr)) {
1716  		pr_err("Invalid module architecture in ELF header: %u\n",
1717  		       info->hdr->e_machine);
1718  		goto no_exec;
1719  	}
1720  	if (info->hdr->e_shentsize != sizeof(Elf_Shdr)) {
1721  		pr_err("Invalid ELF section header size\n");
1722  		goto no_exec;
1723  	}
1724  
1725  	/*
1726  	 * e_shnum is 16 bits, and sizeof(Elf_Shdr) is
1727  	 * known and small. So e_shnum * sizeof(Elf_Shdr)
1728  	 * will not overflow unsigned long on any platform.
1729  	 */
1730  	if (info->hdr->e_shoff >= info->len
1731  	    || (info->hdr->e_shnum * sizeof(Elf_Shdr) >
1732  		info->len - info->hdr->e_shoff)) {
1733  		pr_err("Invalid ELF section header overflow\n");
1734  		goto no_exec;
1735  	}
1736  
1737  	info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
1738  
1739  	/*
1740  	 * Verify if the section name table index is valid.
1741  	 */
1742  	if (info->hdr->e_shstrndx == SHN_UNDEF
1743  	    || info->hdr->e_shstrndx >= info->hdr->e_shnum) {
1744  		pr_err("Invalid ELF section name index: %d || e_shstrndx (%d) >= e_shnum (%d)\n",
1745  		       info->hdr->e_shstrndx, info->hdr->e_shstrndx,
1746  		       info->hdr->e_shnum);
1747  		goto no_exec;
1748  	}
1749  
1750  	strhdr = &info->sechdrs[info->hdr->e_shstrndx];
1751  	err = validate_section_offset(info, strhdr);
1752  	if (err < 0) {
1753  		pr_err("Invalid ELF section hdr(type %u)\n", strhdr->sh_type);
1754  		return err;
1755  	}
1756  
1757  	/*
1758  	 * The section name table must be NUL-terminated, as required
1759  	 * by the spec. This makes strcmp and pr_* calls that access
1760  	 * strings in the section safe.
1761  	 */
1762  	info->secstrings = (void *)info->hdr + strhdr->sh_offset;
1763  	if (strhdr->sh_size == 0) {
1764  		pr_err("empty section name table\n");
1765  		goto no_exec;
1766  	}
1767  	if (info->secstrings[strhdr->sh_size - 1] != '\0') {
1768  		pr_err("ELF Spec violation: section name table isn't null terminated\n");
1769  		goto no_exec;
1770  	}
1771  
1772  	/*
1773  	 * The code assumes that section 0 has a length of zero and
1774  	 * an addr of zero, so check for it.
1775  	 */
1776  	if (info->sechdrs[0].sh_type != SHT_NULL
1777  	    || info->sechdrs[0].sh_size != 0
1778  	    || info->sechdrs[0].sh_addr != 0) {
1779  		pr_err("ELF Spec violation: section 0 type(%d)!=SH_NULL or non-zero len or addr\n",
1780  		       info->sechdrs[0].sh_type);
1781  		goto no_exec;
1782  	}
1783  
1784  	for (i = 1; i < info->hdr->e_shnum; i++) {
1785  		shdr = &info->sechdrs[i];
1786  		switch (shdr->sh_type) {
1787  		case SHT_NULL:
1788  		case SHT_NOBITS:
1789  			continue;
1790  		case SHT_SYMTAB:
1791  			if (shdr->sh_link == SHN_UNDEF
1792  			    || shdr->sh_link >= info->hdr->e_shnum) {
1793  				pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n",
1794  				       shdr->sh_link, shdr->sh_link,
1795  				       info->hdr->e_shnum);
1796  				goto no_exec;
1797  			}
1798  			num_sym_secs++;
1799  			sym_idx = i;
1800  			fallthrough;
1801  		default:
1802  			err = validate_section_offset(info, shdr);
1803  			if (err < 0) {
1804  				pr_err("Invalid ELF section in module (section %u type %u)\n",
1805  					i, shdr->sh_type);
1806  				return err;
1807  			}
1808  			if (strcmp(info->secstrings + shdr->sh_name,
1809  				   ".gnu.linkonce.this_module") == 0) {
1810  				num_mod_secs++;
1811  				mod_idx = i;
1812  			} else if (strcmp(info->secstrings + shdr->sh_name,
1813  				   ".modinfo") == 0) {
1814  				num_info_secs++;
1815  				info_idx = i;
1816  			}
1817  
1818  			if (shdr->sh_flags & SHF_ALLOC) {
1819  				if (shdr->sh_name >= strhdr->sh_size) {
1820  					pr_err("Invalid ELF section name in module (section %u type %u)\n",
1821  					       i, shdr->sh_type);
1822  					return -ENOEXEC;
1823  				}
1824  			}
1825  			break;
1826  		}
1827  	}
1828  
1829  	if (num_info_secs > 1) {
1830  		pr_err("Only one .modinfo section must exist.\n");
1831  		goto no_exec;
1832  	} else if (num_info_secs == 1) {
1833  		/* Try to find a name early so we can log errors with a module name */
1834  		info->index.info = info_idx;
1835  		info->name = get_modinfo(info, "name");
1836  	}
1837  
1838  	if (num_sym_secs != 1) {
1839  		pr_warn("%s: module has no symbols (stripped?)\n",
1840  			info->name ?: "(missing .modinfo section or name field)");
1841  		goto no_exec;
1842  	}
1843  
1844  	/* Sets internal symbols and strings. */
1845  	info->index.sym = sym_idx;
1846  	shdr = &info->sechdrs[sym_idx];
1847  	info->index.str = shdr->sh_link;
1848  	info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset;
1849  
1850  	/*
1851  	 * The ".gnu.linkonce.this_module" ELF section is special. It is
1852  	 * what modpost uses to refer to __this_module and let's use rely
1853  	 * on THIS_MODULE to point to &__this_module properly. The kernel's
1854  	 * modpost declares it on each modules's *.mod.c file. If the struct
1855  	 * module of the kernel changes a full kernel rebuild is required.
1856  	 *
1857  	 * We have a few expectaions for this special section, the following
1858  	 * code validates all this for us:
1859  	 *
1860  	 *   o Only one section must exist
1861  	 *   o We expect the kernel to always have to allocate it: SHF_ALLOC
1862  	 *   o The section size must match the kernel's run time's struct module
1863  	 *     size
1864  	 */
1865  	if (num_mod_secs != 1) {
1866  		pr_err("module %s: Only one .gnu.linkonce.this_module section must exist.\n",
1867  		       info->name ?: "(missing .modinfo section or name field)");
1868  		goto no_exec;
1869  	}
1870  
1871  	shdr = &info->sechdrs[mod_idx];
1872  
1873  	/*
1874  	 * This is already implied on the switch above, however let's be
1875  	 * pedantic about it.
1876  	 */
1877  	if (shdr->sh_type == SHT_NOBITS) {
1878  		pr_err("module %s: .gnu.linkonce.this_module section must have a size set\n",
1879  		       info->name ?: "(missing .modinfo section or name field)");
1880  		goto no_exec;
1881  	}
1882  
1883  	if (!(shdr->sh_flags & SHF_ALLOC)) {
1884  		pr_err("module %s: .gnu.linkonce.this_module must occupy memory during process execution\n",
1885  		       info->name ?: "(missing .modinfo section or name field)");
1886  		goto no_exec;
1887  	}
1888  
1889  	if (shdr->sh_size != sizeof(struct module)) {
1890  		pr_err("module %s: .gnu.linkonce.this_module section size must match the kernel's built struct module size at run time\n",
1891  		       info->name ?: "(missing .modinfo section or name field)");
1892  		goto no_exec;
1893  	}
1894  
1895  	info->index.mod = mod_idx;
1896  
1897  	/* This is temporary: point mod into copy of data. */
1898  	info->mod = (void *)info->hdr + shdr->sh_offset;
1899  
1900  	/*
1901  	 * If we didn't load the .modinfo 'name' field earlier, fall back to
1902  	 * on-disk struct mod 'name' field.
1903  	 */
1904  	if (!info->name)
1905  		info->name = info->mod->name;
1906  
1907  	if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
1908  		info->index.vers = 0; /* Pretend no __versions section! */
1909  	else
1910  		info->index.vers = find_sec(info, "__versions");
1911  
1912  	info->index.pcpu = find_pcpusec(info);
1913  
1914  	return 0;
1915  
1916  no_exec:
1917  	return -ENOEXEC;
1918  }
1919  
1920  #define COPY_CHUNK_SIZE (16*PAGE_SIZE)
1921  
copy_chunked_from_user(void * dst,const void __user * usrc,unsigned long len)1922  static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned long len)
1923  {
1924  	do {
1925  		unsigned long n = min(len, COPY_CHUNK_SIZE);
1926  
1927  		if (copy_from_user(dst, usrc, n) != 0)
1928  			return -EFAULT;
1929  		cond_resched();
1930  		dst += n;
1931  		usrc += n;
1932  		len -= n;
1933  	} while (len);
1934  	return 0;
1935  }
1936  
check_modinfo_livepatch(struct module * mod,struct load_info * info)1937  static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
1938  {
1939  	if (!get_modinfo(info, "livepatch"))
1940  		/* Nothing more to do */
1941  		return 0;
1942  
1943  	if (set_livepatch_module(mod))
1944  		return 0;
1945  
1946  	pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
1947  	       mod->name);
1948  	return -ENOEXEC;
1949  }
1950  
check_modinfo_retpoline(struct module * mod,struct load_info * info)1951  static void check_modinfo_retpoline(struct module *mod, struct load_info *info)
1952  {
1953  	if (retpoline_module_ok(get_modinfo(info, "retpoline")))
1954  		return;
1955  
1956  	pr_warn("%s: loading module not compiled with retpoline compiler.\n",
1957  		mod->name);
1958  }
1959  
1960  /* Sets info->hdr and info->len. */
copy_module_from_user(const void __user * umod,unsigned long len,struct load_info * info)1961  static int copy_module_from_user(const void __user *umod, unsigned long len,
1962  				  struct load_info *info)
1963  {
1964  	int err;
1965  
1966  	info->len = len;
1967  	if (info->len < sizeof(*(info->hdr)))
1968  		return -ENOEXEC;
1969  
1970  	err = security_kernel_load_data(LOADING_MODULE, true);
1971  	if (err)
1972  		return err;
1973  
1974  	/* Suck in entire file: we'll want most of it. */
1975  	info->hdr = __vmalloc(info->len, GFP_KERNEL | __GFP_NOWARN);
1976  	if (!info->hdr)
1977  		return -ENOMEM;
1978  
1979  	if (copy_chunked_from_user(info->hdr, umod, info->len) != 0) {
1980  		err = -EFAULT;
1981  		goto out;
1982  	}
1983  
1984  	err = security_kernel_post_load_data((char *)info->hdr, info->len,
1985  					     LOADING_MODULE, "init_module");
1986  out:
1987  	if (err)
1988  		vfree(info->hdr);
1989  
1990  	return err;
1991  }
1992  
free_copy(struct load_info * info,int flags)1993  static void free_copy(struct load_info *info, int flags)
1994  {
1995  	if (flags & MODULE_INIT_COMPRESSED_FILE)
1996  		module_decompress_cleanup(info);
1997  	else
1998  		vfree(info->hdr);
1999  }
2000  
rewrite_section_headers(struct load_info * info,int flags)2001  static int rewrite_section_headers(struct load_info *info, int flags)
2002  {
2003  	unsigned int i;
2004  
2005  	/* This should always be true, but let's be sure. */
2006  	info->sechdrs[0].sh_addr = 0;
2007  
2008  	for (i = 1; i < info->hdr->e_shnum; i++) {
2009  		Elf_Shdr *shdr = &info->sechdrs[i];
2010  
2011  		/*
2012  		 * Mark all sections sh_addr with their address in the
2013  		 * temporary image.
2014  		 */
2015  		shdr->sh_addr = (size_t)info->hdr + shdr->sh_offset;
2016  
2017  	}
2018  
2019  	/* Track but don't keep modinfo and version sections. */
2020  	info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
2021  	info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
2022  
2023  	return 0;
2024  }
2025  
2026  /*
2027   * These calls taint the kernel depending certain module circumstances */
module_augment_kernel_taints(struct module * mod,struct load_info * info)2028  static void module_augment_kernel_taints(struct module *mod, struct load_info *info)
2029  {
2030  	int prev_taint = test_taint(TAINT_PROPRIETARY_MODULE);
2031  
2032  	if (!get_modinfo(info, "intree")) {
2033  		if (!test_taint(TAINT_OOT_MODULE))
2034  			pr_warn("%s: loading out-of-tree module taints kernel.\n",
2035  				mod->name);
2036  		add_taint_module(mod, TAINT_OOT_MODULE, LOCKDEP_STILL_OK);
2037  	}
2038  
2039  	check_modinfo_retpoline(mod, info);
2040  
2041  	if (get_modinfo(info, "staging")) {
2042  		add_taint_module(mod, TAINT_CRAP, LOCKDEP_STILL_OK);
2043  		pr_warn("%s: module is from the staging directory, the quality "
2044  			"is unknown, you have been warned.\n", mod->name);
2045  	}
2046  
2047  	if (is_livepatch_module(mod)) {
2048  		add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
2049  		pr_notice_once("%s: tainting kernel with TAINT_LIVEPATCH\n",
2050  				mod->name);
2051  	}
2052  
2053  	module_license_taint_check(mod, get_modinfo(info, "license"));
2054  
2055  	if (get_modinfo(info, "test")) {
2056  		if (!test_taint(TAINT_TEST))
2057  			pr_warn("%s: loading test module taints kernel.\n",
2058  				mod->name);
2059  		add_taint_module(mod, TAINT_TEST, LOCKDEP_STILL_OK);
2060  	}
2061  #ifdef CONFIG_MODULE_SIG
2062  	mod->sig_ok = info->sig_ok;
2063  	if (!mod->sig_ok) {
2064  		pr_notice_once("%s: module verification failed: signature "
2065  			       "and/or required key missing - tainting "
2066  			       "kernel\n", mod->name);
2067  		add_taint_module(mod, TAINT_UNSIGNED_MODULE, LOCKDEP_STILL_OK);
2068  	}
2069  #endif
2070  
2071  	/*
2072  	 * ndiswrapper is under GPL by itself, but loads proprietary modules.
2073  	 * Don't use add_taint_module(), as it would prevent ndiswrapper from
2074  	 * using GPL-only symbols it needs.
2075  	 */
2076  	if (strcmp(mod->name, "ndiswrapper") == 0)
2077  		add_taint(TAINT_PROPRIETARY_MODULE, LOCKDEP_NOW_UNRELIABLE);
2078  
2079  	/* driverloader was caught wrongly pretending to be under GPL */
2080  	if (strcmp(mod->name, "driverloader") == 0)
2081  		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2082  				 LOCKDEP_NOW_UNRELIABLE);
2083  
2084  	/* lve claims to be GPL but upstream won't provide source */
2085  	if (strcmp(mod->name, "lve") == 0)
2086  		add_taint_module(mod, TAINT_PROPRIETARY_MODULE,
2087  				 LOCKDEP_NOW_UNRELIABLE);
2088  
2089  	if (!prev_taint && test_taint(TAINT_PROPRIETARY_MODULE))
2090  		pr_warn("%s: module license taints kernel.\n", mod->name);
2091  
2092  }
2093  
check_modinfo(struct module * mod,struct load_info * info,int flags)2094  static int check_modinfo(struct module *mod, struct load_info *info, int flags)
2095  {
2096  	const char *modmagic = get_modinfo(info, "vermagic");
2097  	int err;
2098  
2099  	if (flags & MODULE_INIT_IGNORE_VERMAGIC)
2100  		modmagic = NULL;
2101  
2102  	/* This is allowed: modprobe --force will invalidate it. */
2103  	if (!modmagic) {
2104  		err = try_to_force_load(mod, "bad vermagic");
2105  		if (err)
2106  			return err;
2107  	} else if (!same_magic(modmagic, vermagic, info->index.vers)) {
2108  		pr_err("%s: version magic '%s' should be '%s'\n",
2109  		       info->name, modmagic, vermagic);
2110  		return -ENOEXEC;
2111  	}
2112  
2113  	err = check_modinfo_livepatch(mod, info);
2114  	if (err)
2115  		return err;
2116  
2117  	return 0;
2118  }
2119  
find_module_sections(struct module * mod,struct load_info * info)2120  static int find_module_sections(struct module *mod, struct load_info *info)
2121  {
2122  	mod->kp = section_objs(info, "__param",
2123  			       sizeof(*mod->kp), &mod->num_kp);
2124  	mod->syms = section_objs(info, "__ksymtab",
2125  				 sizeof(*mod->syms), &mod->num_syms);
2126  	mod->crcs = section_addr(info, "__kcrctab");
2127  	mod->gpl_syms = section_objs(info, "__ksymtab_gpl",
2128  				     sizeof(*mod->gpl_syms),
2129  				     &mod->num_gpl_syms);
2130  	mod->gpl_crcs = section_addr(info, "__kcrctab_gpl");
2131  
2132  #ifdef CONFIG_CONSTRUCTORS
2133  	mod->ctors = section_objs(info, ".ctors",
2134  				  sizeof(*mod->ctors), &mod->num_ctors);
2135  	if (!mod->ctors)
2136  		mod->ctors = section_objs(info, ".init_array",
2137  				sizeof(*mod->ctors), &mod->num_ctors);
2138  	else if (find_sec(info, ".init_array")) {
2139  		/*
2140  		 * This shouldn't happen with same compiler and binutils
2141  		 * building all parts of the module.
2142  		 */
2143  		pr_warn("%s: has both .ctors and .init_array.\n",
2144  		       mod->name);
2145  		return -EINVAL;
2146  	}
2147  #endif
2148  
2149  	mod->noinstr_text_start = section_objs(info, ".noinstr.text", 1,
2150  						&mod->noinstr_text_size);
2151  
2152  #ifdef CONFIG_TRACEPOINTS
2153  	mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs",
2154  					     sizeof(*mod->tracepoints_ptrs),
2155  					     &mod->num_tracepoints);
2156  #endif
2157  #ifdef CONFIG_TREE_SRCU
2158  	mod->srcu_struct_ptrs = section_objs(info, "___srcu_struct_ptrs",
2159  					     sizeof(*mod->srcu_struct_ptrs),
2160  					     &mod->num_srcu_structs);
2161  #endif
2162  #ifdef CONFIG_BPF_EVENTS
2163  	mod->bpf_raw_events = section_objs(info, "__bpf_raw_tp_map",
2164  					   sizeof(*mod->bpf_raw_events),
2165  					   &mod->num_bpf_raw_events);
2166  #endif
2167  #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
2168  	mod->btf_data = any_section_objs(info, ".BTF", 1, &mod->btf_data_size);
2169  	mod->btf_base_data = any_section_objs(info, ".BTF.base", 1,
2170  					      &mod->btf_base_data_size);
2171  #endif
2172  #ifdef CONFIG_JUMP_LABEL
2173  	mod->jump_entries = section_objs(info, "__jump_table",
2174  					sizeof(*mod->jump_entries),
2175  					&mod->num_jump_entries);
2176  #endif
2177  #ifdef CONFIG_EVENT_TRACING
2178  	mod->trace_events = section_objs(info, "_ftrace_events",
2179  					 sizeof(*mod->trace_events),
2180  					 &mod->num_trace_events);
2181  	mod->trace_evals = section_objs(info, "_ftrace_eval_map",
2182  					sizeof(*mod->trace_evals),
2183  					&mod->num_trace_evals);
2184  #endif
2185  #ifdef CONFIG_TRACING
2186  	mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
2187  					 sizeof(*mod->trace_bprintk_fmt_start),
2188  					 &mod->num_trace_bprintk_fmt);
2189  #endif
2190  #ifdef CONFIG_FTRACE_MCOUNT_RECORD
2191  	/* sechdrs[0].sh_size is always zero */
2192  	mod->ftrace_callsites = section_objs(info, FTRACE_CALLSITE_SECTION,
2193  					     sizeof(*mod->ftrace_callsites),
2194  					     &mod->num_ftrace_callsites);
2195  #endif
2196  #ifdef CONFIG_FUNCTION_ERROR_INJECTION
2197  	mod->ei_funcs = section_objs(info, "_error_injection_whitelist",
2198  					    sizeof(*mod->ei_funcs),
2199  					    &mod->num_ei_funcs);
2200  #endif
2201  #ifdef CONFIG_KPROBES
2202  	mod->kprobes_text_start = section_objs(info, ".kprobes.text", 1,
2203  						&mod->kprobes_text_size);
2204  	mod->kprobe_blacklist = section_objs(info, "_kprobe_blacklist",
2205  						sizeof(unsigned long),
2206  						&mod->num_kprobe_blacklist);
2207  #endif
2208  #ifdef CONFIG_PRINTK_INDEX
2209  	mod->printk_index_start = section_objs(info, ".printk_index",
2210  					       sizeof(*mod->printk_index_start),
2211  					       &mod->printk_index_size);
2212  #endif
2213  #ifdef CONFIG_HAVE_STATIC_CALL_INLINE
2214  	mod->static_call_sites = section_objs(info, ".static_call_sites",
2215  					      sizeof(*mod->static_call_sites),
2216  					      &mod->num_static_call_sites);
2217  #endif
2218  #if IS_ENABLED(CONFIG_KUNIT)
2219  	mod->kunit_suites = section_objs(info, ".kunit_test_suites",
2220  					      sizeof(*mod->kunit_suites),
2221  					      &mod->num_kunit_suites);
2222  	mod->kunit_init_suites = section_objs(info, ".kunit_init_test_suites",
2223  					      sizeof(*mod->kunit_init_suites),
2224  					      &mod->num_kunit_init_suites);
2225  #endif
2226  
2227  	mod->extable = section_objs(info, "__ex_table",
2228  				    sizeof(*mod->extable), &mod->num_exentries);
2229  
2230  	if (section_addr(info, "__obsparm"))
2231  		pr_warn("%s: Ignoring obsolete parameters\n", mod->name);
2232  
2233  #ifdef CONFIG_DYNAMIC_DEBUG_CORE
2234  	mod->dyndbg_info.descs = section_objs(info, "__dyndbg",
2235  					      sizeof(*mod->dyndbg_info.descs),
2236  					      &mod->dyndbg_info.num_descs);
2237  	mod->dyndbg_info.classes = section_objs(info, "__dyndbg_classes",
2238  						sizeof(*mod->dyndbg_info.classes),
2239  						&mod->dyndbg_info.num_classes);
2240  #endif
2241  
2242  	return 0;
2243  }
2244  
move_module(struct module * mod,struct load_info * info)2245  static int move_module(struct module *mod, struct load_info *info)
2246  {
2247  	int i;
2248  	enum mod_mem_type t = 0;
2249  	int ret = -ENOMEM;
2250  
2251  	for_each_mod_mem_type(type) {
2252  		if (!mod->mem[type].size) {
2253  			mod->mem[type].base = NULL;
2254  			continue;
2255  		}
2256  
2257  		ret = module_memory_alloc(mod, type);
2258  		if (ret) {
2259  			t = type;
2260  			goto out_enomem;
2261  		}
2262  	}
2263  
2264  	/* Transfer each section which specifies SHF_ALLOC */
2265  	pr_debug("Final section addresses for %s:\n", mod->name);
2266  	for (i = 0; i < info->hdr->e_shnum; i++) {
2267  		void *dest;
2268  		Elf_Shdr *shdr = &info->sechdrs[i];
2269  		enum mod_mem_type type = shdr->sh_entsize >> SH_ENTSIZE_TYPE_SHIFT;
2270  
2271  		if (!(shdr->sh_flags & SHF_ALLOC))
2272  			continue;
2273  
2274  		dest = mod->mem[type].base + (shdr->sh_entsize & SH_ENTSIZE_OFFSET_MASK);
2275  
2276  		if (shdr->sh_type != SHT_NOBITS) {
2277  			/*
2278  			 * Our ELF checker already validated this, but let's
2279  			 * be pedantic and make the goal clearer. We actually
2280  			 * end up copying over all modifications made to the
2281  			 * userspace copy of the entire struct module.
2282  			 */
2283  			if (i == info->index.mod &&
2284  			   (WARN_ON_ONCE(shdr->sh_size != sizeof(struct module)))) {
2285  				ret = -ENOEXEC;
2286  				goto out_enomem;
2287  			}
2288  			memcpy(dest, (void *)shdr->sh_addr, shdr->sh_size);
2289  		}
2290  		/*
2291  		 * Update the userspace copy's ELF section address to point to
2292  		 * our newly allocated memory as a pure convenience so that
2293  		 * users of info can keep taking advantage and using the newly
2294  		 * minted official memory area.
2295  		 */
2296  		shdr->sh_addr = (unsigned long)dest;
2297  		pr_debug("\t0x%lx 0x%.8lx %s\n", (long)shdr->sh_addr,
2298  			 (long)shdr->sh_size, info->secstrings + shdr->sh_name);
2299  	}
2300  
2301  	return 0;
2302  out_enomem:
2303  	for (t--; t >= 0; t--)
2304  		module_memory_free(mod, t, true);
2305  	return ret;
2306  }
2307  
check_export_symbol_versions(struct module * mod)2308  static int check_export_symbol_versions(struct module *mod)
2309  {
2310  #ifdef CONFIG_MODVERSIONS
2311  	if ((mod->num_syms && !mod->crcs) ||
2312  	    (mod->num_gpl_syms && !mod->gpl_crcs)) {
2313  		return try_to_force_load(mod,
2314  					 "no versions for exported symbols");
2315  	}
2316  #endif
2317  	return 0;
2318  }
2319  
flush_module_icache(const struct module * mod)2320  static void flush_module_icache(const struct module *mod)
2321  {
2322  	/*
2323  	 * Flush the instruction cache, since we've played with text.
2324  	 * Do it before processing of module parameters, so the module
2325  	 * can provide parameter accessor functions of its own.
2326  	 */
2327  	for_each_mod_mem_type(type) {
2328  		const struct module_memory *mod_mem = &mod->mem[type];
2329  
2330  		if (mod_mem->size) {
2331  			flush_icache_range((unsigned long)mod_mem->base,
2332  					   (unsigned long)mod_mem->base + mod_mem->size);
2333  		}
2334  	}
2335  }
2336  
module_elf_check_arch(Elf_Ehdr * hdr)2337  bool __weak module_elf_check_arch(Elf_Ehdr *hdr)
2338  {
2339  	return true;
2340  }
2341  
module_frob_arch_sections(Elf_Ehdr * hdr,Elf_Shdr * sechdrs,char * secstrings,struct module * mod)2342  int __weak module_frob_arch_sections(Elf_Ehdr *hdr,
2343  				     Elf_Shdr *sechdrs,
2344  				     char *secstrings,
2345  				     struct module *mod)
2346  {
2347  	return 0;
2348  }
2349  
2350  /* module_blacklist is a comma-separated list of module names */
2351  static char *module_blacklist;
blacklisted(const char * module_name)2352  static bool blacklisted(const char *module_name)
2353  {
2354  	const char *p;
2355  	size_t len;
2356  
2357  	if (!module_blacklist)
2358  		return false;
2359  
2360  	for (p = module_blacklist; *p; p += len) {
2361  		len = strcspn(p, ",");
2362  		if (strlen(module_name) == len && !memcmp(module_name, p, len))
2363  			return true;
2364  		if (p[len] == ',')
2365  			len++;
2366  	}
2367  	return false;
2368  }
2369  core_param(module_blacklist, module_blacklist, charp, 0400);
2370  
layout_and_allocate(struct load_info * info,int flags)2371  static struct module *layout_and_allocate(struct load_info *info, int flags)
2372  {
2373  	struct module *mod;
2374  	unsigned int ndx;
2375  	int err;
2376  
2377  	/* Allow arches to frob section contents and sizes.  */
2378  	err = module_frob_arch_sections(info->hdr, info->sechdrs,
2379  					info->secstrings, info->mod);
2380  	if (err < 0)
2381  		return ERR_PTR(err);
2382  
2383  	err = module_enforce_rwx_sections(info->hdr, info->sechdrs,
2384  					  info->secstrings, info->mod);
2385  	if (err < 0)
2386  		return ERR_PTR(err);
2387  
2388  	/* We will do a special allocation for per-cpu sections later. */
2389  	info->sechdrs[info->index.pcpu].sh_flags &= ~(unsigned long)SHF_ALLOC;
2390  
2391  	/*
2392  	 * Mark ro_after_init section with SHF_RO_AFTER_INIT so that
2393  	 * layout_sections() can put it in the right place.
2394  	 * Note: ro_after_init sections also have SHF_{WRITE,ALLOC} set.
2395  	 */
2396  	ndx = find_sec(info, ".data..ro_after_init");
2397  	if (ndx)
2398  		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
2399  	/*
2400  	 * Mark the __jump_table section as ro_after_init as well: these data
2401  	 * structures are never modified, with the exception of entries that
2402  	 * refer to code in the __init section, which are annotated as such
2403  	 * at module load time.
2404  	 */
2405  	ndx = find_sec(info, "__jump_table");
2406  	if (ndx)
2407  		info->sechdrs[ndx].sh_flags |= SHF_RO_AFTER_INIT;
2408  
2409  	/*
2410  	 * Determine total sizes, and put offsets in sh_entsize.  For now
2411  	 * this is done generically; there doesn't appear to be any
2412  	 * special cases for the architectures.
2413  	 */
2414  	layout_sections(info->mod, info);
2415  	layout_symtab(info->mod, info);
2416  
2417  	/* Allocate and move to the final place */
2418  	err = move_module(info->mod, info);
2419  	if (err)
2420  		return ERR_PTR(err);
2421  
2422  	/* Module has been copied to its final place now: return it. */
2423  	mod = (void *)info->sechdrs[info->index.mod].sh_addr;
2424  	kmemleak_load_module(mod, info);
2425  	return mod;
2426  }
2427  
2428  /* mod is no longer valid after this! */
module_deallocate(struct module * mod,struct load_info * info)2429  static void module_deallocate(struct module *mod, struct load_info *info)
2430  {
2431  	percpu_modfree(mod);
2432  	module_arch_freeing_init(mod);
2433  
2434  	free_mod_mem(mod, true);
2435  }
2436  
module_finalize(const Elf_Ehdr * hdr,const Elf_Shdr * sechdrs,struct module * me)2437  int __weak module_finalize(const Elf_Ehdr *hdr,
2438  			   const Elf_Shdr *sechdrs,
2439  			   struct module *me)
2440  {
2441  	return 0;
2442  }
2443  
post_relocation(struct module * mod,const struct load_info * info)2444  static int post_relocation(struct module *mod, const struct load_info *info)
2445  {
2446  	/* Sort exception table now relocations are done. */
2447  	sort_extable(mod->extable, mod->extable + mod->num_exentries);
2448  
2449  	/* Copy relocated percpu area over. */
2450  	percpu_modcopy(mod, (void *)info->sechdrs[info->index.pcpu].sh_addr,
2451  		       info->sechdrs[info->index.pcpu].sh_size);
2452  
2453  	/* Setup kallsyms-specific fields. */
2454  	add_kallsyms(mod, info);
2455  
2456  	/* Arch-specific module finalizing. */
2457  	return module_finalize(info->hdr, info->sechdrs, mod);
2458  }
2459  
2460  /* Call module constructors. */
do_mod_ctors(struct module * mod)2461  static void do_mod_ctors(struct module *mod)
2462  {
2463  #ifdef CONFIG_CONSTRUCTORS
2464  	unsigned long i;
2465  
2466  	for (i = 0; i < mod->num_ctors; i++)
2467  		mod->ctors[i]();
2468  #endif
2469  }
2470  
2471  /* For freeing module_init on success, in case kallsyms traversing */
2472  struct mod_initfree {
2473  	struct llist_node node;
2474  	void *init_text;
2475  	void *init_data;
2476  	void *init_rodata;
2477  };
2478  
do_free_init(struct work_struct * w)2479  static void do_free_init(struct work_struct *w)
2480  {
2481  	struct llist_node *pos, *n, *list;
2482  	struct mod_initfree *initfree;
2483  
2484  	list = llist_del_all(&init_free_list);
2485  
2486  	synchronize_rcu();
2487  
2488  	llist_for_each_safe(pos, n, list) {
2489  		initfree = container_of(pos, struct mod_initfree, node);
2490  		execmem_free(initfree->init_text);
2491  		execmem_free(initfree->init_data);
2492  		execmem_free(initfree->init_rodata);
2493  		kfree(initfree);
2494  	}
2495  }
2496  
flush_module_init_free_work(void)2497  void flush_module_init_free_work(void)
2498  {
2499  	flush_work(&init_free_wq);
2500  }
2501  
2502  #undef MODULE_PARAM_PREFIX
2503  #define MODULE_PARAM_PREFIX "module."
2504  /* Default value for module->async_probe_requested */
2505  static bool async_probe;
2506  module_param(async_probe, bool, 0644);
2507  
2508  /*
2509   * This is where the real work happens.
2510   *
2511   * Keep it uninlined to provide a reliable breakpoint target, e.g. for the gdb
2512   * helper command 'lx-symbols'.
2513   */
do_init_module(struct module * mod)2514  static noinline int do_init_module(struct module *mod)
2515  {
2516  	int ret = 0;
2517  	struct mod_initfree *freeinit;
2518  #if defined(CONFIG_MODULE_STATS)
2519  	unsigned int text_size = 0, total_size = 0;
2520  
2521  	for_each_mod_mem_type(type) {
2522  		const struct module_memory *mod_mem = &mod->mem[type];
2523  		if (mod_mem->size) {
2524  			total_size += mod_mem->size;
2525  			if (type == MOD_TEXT || type == MOD_INIT_TEXT)
2526  				text_size += mod_mem->size;
2527  		}
2528  	}
2529  #endif
2530  
2531  	freeinit = kmalloc(sizeof(*freeinit), GFP_KERNEL);
2532  	if (!freeinit) {
2533  		ret = -ENOMEM;
2534  		goto fail;
2535  	}
2536  	freeinit->init_text = mod->mem[MOD_INIT_TEXT].base;
2537  	freeinit->init_data = mod->mem[MOD_INIT_DATA].base;
2538  	freeinit->init_rodata = mod->mem[MOD_INIT_RODATA].base;
2539  
2540  	do_mod_ctors(mod);
2541  	/* Start the module */
2542  	if (mod->init != NULL)
2543  		ret = do_one_initcall(mod->init);
2544  	if (ret < 0) {
2545  		goto fail_free_freeinit;
2546  	}
2547  	if (ret > 0) {
2548  		pr_warn("%s: '%s'->init suspiciously returned %d, it should "
2549  			"follow 0/-E convention\n"
2550  			"%s: loading module anyway...\n",
2551  			__func__, mod->name, ret, __func__);
2552  		dump_stack();
2553  	}
2554  
2555  	/* Now it's a first class citizen! */
2556  	mod->state = MODULE_STATE_LIVE;
2557  	blocking_notifier_call_chain(&module_notify_list,
2558  				     MODULE_STATE_LIVE, mod);
2559  
2560  	/* Delay uevent until module has finished its init routine */
2561  	kobject_uevent(&mod->mkobj.kobj, KOBJ_ADD);
2562  
2563  	/*
2564  	 * We need to finish all async code before the module init sequence
2565  	 * is done. This has potential to deadlock if synchronous module
2566  	 * loading is requested from async (which is not allowed!).
2567  	 *
2568  	 * See commit 0fdff3ec6d87 ("async, kmod: warn on synchronous
2569  	 * request_module() from async workers") for more details.
2570  	 */
2571  	if (!mod->async_probe_requested)
2572  		async_synchronize_full();
2573  
2574  	ftrace_free_mem(mod, mod->mem[MOD_INIT_TEXT].base,
2575  			mod->mem[MOD_INIT_TEXT].base + mod->mem[MOD_INIT_TEXT].size);
2576  	mutex_lock(&module_mutex);
2577  	/* Drop initial reference. */
2578  	module_put(mod);
2579  	trim_init_extable(mod);
2580  #ifdef CONFIG_KALLSYMS
2581  	/* Switch to core kallsyms now init is done: kallsyms may be walking! */
2582  	rcu_assign_pointer(mod->kallsyms, &mod->core_kallsyms);
2583  #endif
2584  	ret = module_enable_rodata_ro(mod, true);
2585  	if (ret)
2586  		goto fail_mutex_unlock;
2587  	mod_tree_remove_init(mod);
2588  	module_arch_freeing_init(mod);
2589  	for_class_mod_mem_type(type, init) {
2590  		mod->mem[type].base = NULL;
2591  		mod->mem[type].size = 0;
2592  	}
2593  
2594  #ifdef CONFIG_DEBUG_INFO_BTF_MODULES
2595  	/* .BTF is not SHF_ALLOC and will get removed, so sanitize pointers */
2596  	mod->btf_data = NULL;
2597  	mod->btf_base_data = NULL;
2598  #endif
2599  	/*
2600  	 * We want to free module_init, but be aware that kallsyms may be
2601  	 * walking this with preempt disabled.  In all the failure paths, we
2602  	 * call synchronize_rcu(), but we don't want to slow down the success
2603  	 * path. execmem_free() cannot be called in an interrupt, so do the
2604  	 * work and call synchronize_rcu() in a work queue.
2605  	 *
2606  	 * Note that execmem_alloc() on most architectures creates W+X page
2607  	 * mappings which won't be cleaned up until do_free_init() runs.  Any
2608  	 * code such as mark_rodata_ro() which depends on those mappings to
2609  	 * be cleaned up needs to sync with the queued work by invoking
2610  	 * flush_module_init_free_work().
2611  	 */
2612  	if (llist_add(&freeinit->node, &init_free_list))
2613  		schedule_work(&init_free_wq);
2614  
2615  	mutex_unlock(&module_mutex);
2616  	wake_up_all(&module_wq);
2617  
2618  	mod_stat_add_long(text_size, &total_text_size);
2619  	mod_stat_add_long(total_size, &total_mod_size);
2620  
2621  	mod_stat_inc(&modcount);
2622  
2623  	return 0;
2624  
2625  fail_mutex_unlock:
2626  	mutex_unlock(&module_mutex);
2627  fail_free_freeinit:
2628  	kfree(freeinit);
2629  fail:
2630  	/* Try to protect us from buggy refcounters. */
2631  	mod->state = MODULE_STATE_GOING;
2632  	synchronize_rcu();
2633  	module_put(mod);
2634  	blocking_notifier_call_chain(&module_notify_list,
2635  				     MODULE_STATE_GOING, mod);
2636  	klp_module_going(mod);
2637  	ftrace_release_mod(mod);
2638  	free_module(mod);
2639  	wake_up_all(&module_wq);
2640  
2641  	return ret;
2642  }
2643  
may_init_module(void)2644  static int may_init_module(void)
2645  {
2646  	if (!capable(CAP_SYS_MODULE) || modules_disabled)
2647  		return -EPERM;
2648  
2649  	return 0;
2650  }
2651  
2652  /* Is this module of this name done loading?  No locks held. */
finished_loading(const char * name)2653  static bool finished_loading(const char *name)
2654  {
2655  	struct module *mod;
2656  	bool ret;
2657  
2658  	/*
2659  	 * The module_mutex should not be a heavily contended lock;
2660  	 * if we get the occasional sleep here, we'll go an extra iteration
2661  	 * in the wait_event_interruptible(), which is harmless.
2662  	 */
2663  	sched_annotate_sleep();
2664  	mutex_lock(&module_mutex);
2665  	mod = find_module_all(name, strlen(name), true);
2666  	ret = !mod || mod->state == MODULE_STATE_LIVE
2667  		|| mod->state == MODULE_STATE_GOING;
2668  	mutex_unlock(&module_mutex);
2669  
2670  	return ret;
2671  }
2672  
2673  /* Must be called with module_mutex held */
module_patient_check_exists(const char * name,enum fail_dup_mod_reason reason)2674  static int module_patient_check_exists(const char *name,
2675  				       enum fail_dup_mod_reason reason)
2676  {
2677  	struct module *old;
2678  	int err = 0;
2679  
2680  	old = find_module_all(name, strlen(name), true);
2681  	if (old == NULL)
2682  		return 0;
2683  
2684  	if (old->state == MODULE_STATE_COMING ||
2685  	    old->state == MODULE_STATE_UNFORMED) {
2686  		/* Wait in case it fails to load. */
2687  		mutex_unlock(&module_mutex);
2688  		err = wait_event_interruptible(module_wq,
2689  				       finished_loading(name));
2690  		mutex_lock(&module_mutex);
2691  		if (err)
2692  			return err;
2693  
2694  		/* The module might have gone in the meantime. */
2695  		old = find_module_all(name, strlen(name), true);
2696  	}
2697  
2698  	if (try_add_failed_module(name, reason))
2699  		pr_warn("Could not add fail-tracking for module: %s\n", name);
2700  
2701  	/*
2702  	 * We are here only when the same module was being loaded. Do
2703  	 * not try to load it again right now. It prevents long delays
2704  	 * caused by serialized module load failures. It might happen
2705  	 * when more devices of the same type trigger load of
2706  	 * a particular module.
2707  	 */
2708  	if (old && old->state == MODULE_STATE_LIVE)
2709  		return -EEXIST;
2710  	return -EBUSY;
2711  }
2712  
2713  /*
2714   * We try to place it in the list now to make sure it's unique before
2715   * we dedicate too many resources.  In particular, temporary percpu
2716   * memory exhaustion.
2717   */
add_unformed_module(struct module * mod)2718  static int add_unformed_module(struct module *mod)
2719  {
2720  	int err;
2721  
2722  	mod->state = MODULE_STATE_UNFORMED;
2723  
2724  	mutex_lock(&module_mutex);
2725  	err = module_patient_check_exists(mod->name, FAIL_DUP_MOD_LOAD);
2726  	if (err)
2727  		goto out;
2728  
2729  	mod_update_bounds(mod);
2730  	list_add_rcu(&mod->list, &modules);
2731  	mod_tree_insert(mod);
2732  	err = 0;
2733  
2734  out:
2735  	mutex_unlock(&module_mutex);
2736  	return err;
2737  }
2738  
complete_formation(struct module * mod,struct load_info * info)2739  static int complete_formation(struct module *mod, struct load_info *info)
2740  {
2741  	int err;
2742  
2743  	mutex_lock(&module_mutex);
2744  
2745  	/* Find duplicate symbols (must be called under lock). */
2746  	err = verify_exported_symbols(mod);
2747  	if (err < 0)
2748  		goto out;
2749  
2750  	/* These rely on module_mutex for list integrity. */
2751  	module_bug_finalize(info->hdr, info->sechdrs, mod);
2752  	module_cfi_finalize(info->hdr, info->sechdrs, mod);
2753  
2754  	err = module_enable_rodata_ro(mod, false);
2755  	if (err)
2756  		goto out_strict_rwx;
2757  	err = module_enable_data_nx(mod);
2758  	if (err)
2759  		goto out_strict_rwx;
2760  	err = module_enable_text_rox(mod);
2761  	if (err)
2762  		goto out_strict_rwx;
2763  
2764  	/*
2765  	 * Mark state as coming so strong_try_module_get() ignores us,
2766  	 * but kallsyms etc. can see us.
2767  	 */
2768  	mod->state = MODULE_STATE_COMING;
2769  	mutex_unlock(&module_mutex);
2770  
2771  	return 0;
2772  
2773  out_strict_rwx:
2774  	module_bug_cleanup(mod);
2775  out:
2776  	mutex_unlock(&module_mutex);
2777  	return err;
2778  }
2779  
prepare_coming_module(struct module * mod)2780  static int prepare_coming_module(struct module *mod)
2781  {
2782  	int err;
2783  
2784  	ftrace_module_enable(mod);
2785  	err = klp_module_coming(mod);
2786  	if (err)
2787  		return err;
2788  
2789  	err = blocking_notifier_call_chain_robust(&module_notify_list,
2790  			MODULE_STATE_COMING, MODULE_STATE_GOING, mod);
2791  	err = notifier_to_errno(err);
2792  	if (err)
2793  		klp_module_going(mod);
2794  
2795  	return err;
2796  }
2797  
unknown_module_param_cb(char * param,char * val,const char * modname,void * arg)2798  static int unknown_module_param_cb(char *param, char *val, const char *modname,
2799  				   void *arg)
2800  {
2801  	struct module *mod = arg;
2802  	int ret;
2803  
2804  	if (strcmp(param, "async_probe") == 0) {
2805  		if (kstrtobool(val, &mod->async_probe_requested))
2806  			mod->async_probe_requested = true;
2807  		return 0;
2808  	}
2809  
2810  	/* Check for magic 'dyndbg' arg */
2811  	ret = ddebug_dyndbg_module_param_cb(param, val, modname);
2812  	if (ret != 0)
2813  		pr_warn("%s: unknown parameter '%s' ignored\n", modname, param);
2814  	return 0;
2815  }
2816  
2817  /* Module within temporary copy, this doesn't do any allocation  */
early_mod_check(struct load_info * info,int flags)2818  static int early_mod_check(struct load_info *info, int flags)
2819  {
2820  	int err;
2821  
2822  	/*
2823  	 * Now that we know we have the correct module name, check
2824  	 * if it's blacklisted.
2825  	 */
2826  	if (blacklisted(info->name)) {
2827  		pr_err("Module %s is blacklisted\n", info->name);
2828  		return -EPERM;
2829  	}
2830  
2831  	err = rewrite_section_headers(info, flags);
2832  	if (err)
2833  		return err;
2834  
2835  	/* Check module struct version now, before we try to use module. */
2836  	if (!check_modstruct_version(info, info->mod))
2837  		return -ENOEXEC;
2838  
2839  	err = check_modinfo(info->mod, info, flags);
2840  	if (err)
2841  		return err;
2842  
2843  	mutex_lock(&module_mutex);
2844  	err = module_patient_check_exists(info->mod->name, FAIL_DUP_MOD_BECOMING);
2845  	mutex_unlock(&module_mutex);
2846  
2847  	return err;
2848  }
2849  
2850  /*
2851   * Allocate and load the module: note that size of section 0 is always
2852   * zero, and we rely on this for optional sections.
2853   */
load_module(struct load_info * info,const char __user * uargs,int flags)2854  static int load_module(struct load_info *info, const char __user *uargs,
2855  		       int flags)
2856  {
2857  	struct module *mod;
2858  	bool module_allocated = false;
2859  	long err = 0;
2860  	char *after_dashes;
2861  
2862  	/*
2863  	 * Do the signature check (if any) first. All that
2864  	 * the signature check needs is info->len, it does
2865  	 * not need any of the section info. That can be
2866  	 * set up later. This will minimize the chances
2867  	 * of a corrupt module causing problems before
2868  	 * we even get to the signature check.
2869  	 *
2870  	 * The check will also adjust info->len by stripping
2871  	 * off the sig length at the end of the module, making
2872  	 * checks against info->len more correct.
2873  	 */
2874  	err = module_sig_check(info, flags);
2875  	if (err)
2876  		goto free_copy;
2877  
2878  	/*
2879  	 * Do basic sanity checks against the ELF header and
2880  	 * sections. Cache useful sections and set the
2881  	 * info->mod to the userspace passed struct module.
2882  	 */
2883  	err = elf_validity_cache_copy(info, flags);
2884  	if (err)
2885  		goto free_copy;
2886  
2887  	err = early_mod_check(info, flags);
2888  	if (err)
2889  		goto free_copy;
2890  
2891  	/* Figure out module layout, and allocate all the memory. */
2892  	mod = layout_and_allocate(info, flags);
2893  	if (IS_ERR(mod)) {
2894  		err = PTR_ERR(mod);
2895  		goto free_copy;
2896  	}
2897  
2898  	module_allocated = true;
2899  
2900  	audit_log_kern_module(mod->name);
2901  
2902  	/* Reserve our place in the list. */
2903  	err = add_unformed_module(mod);
2904  	if (err)
2905  		goto free_module;
2906  
2907  	/*
2908  	 * We are tainting your kernel if your module gets into
2909  	 * the modules linked list somehow.
2910  	 */
2911  	module_augment_kernel_taints(mod, info);
2912  
2913  	/* To avoid stressing percpu allocator, do this once we're unique. */
2914  	err = percpu_modalloc(mod, info);
2915  	if (err)
2916  		goto unlink_mod;
2917  
2918  	/* Now module is in final location, initialize linked lists, etc. */
2919  	err = module_unload_init(mod);
2920  	if (err)
2921  		goto unlink_mod;
2922  
2923  	init_param_lock(mod);
2924  
2925  	/*
2926  	 * Now we've got everything in the final locations, we can
2927  	 * find optional sections.
2928  	 */
2929  	err = find_module_sections(mod, info);
2930  	if (err)
2931  		goto free_unload;
2932  
2933  	err = check_export_symbol_versions(mod);
2934  	if (err)
2935  		goto free_unload;
2936  
2937  	/* Set up MODINFO_ATTR fields */
2938  	setup_modinfo(mod, info);
2939  
2940  	/* Fix up syms, so that st_value is a pointer to location. */
2941  	err = simplify_symbols(mod, info);
2942  	if (err < 0)
2943  		goto free_modinfo;
2944  
2945  	err = apply_relocations(mod, info);
2946  	if (err < 0)
2947  		goto free_modinfo;
2948  
2949  	err = post_relocation(mod, info);
2950  	if (err < 0)
2951  		goto free_modinfo;
2952  
2953  	flush_module_icache(mod);
2954  
2955  	/* Now copy in args */
2956  	mod->args = strndup_user(uargs, ~0UL >> 1);
2957  	if (IS_ERR(mod->args)) {
2958  		err = PTR_ERR(mod->args);
2959  		goto free_arch_cleanup;
2960  	}
2961  
2962  	init_build_id(mod, info);
2963  
2964  	/* Ftrace init must be called in the MODULE_STATE_UNFORMED state */
2965  	ftrace_module_init(mod);
2966  
2967  	/* Finally it's fully formed, ready to start executing. */
2968  	err = complete_formation(mod, info);
2969  	if (err)
2970  		goto ddebug_cleanup;
2971  
2972  	err = prepare_coming_module(mod);
2973  	if (err)
2974  		goto bug_cleanup;
2975  
2976  	mod->async_probe_requested = async_probe;
2977  
2978  	/* Module is ready to execute: parsing args may do that. */
2979  	after_dashes = parse_args(mod->name, mod->args, mod->kp, mod->num_kp,
2980  				  -32768, 32767, mod,
2981  				  unknown_module_param_cb);
2982  	if (IS_ERR(after_dashes)) {
2983  		err = PTR_ERR(after_dashes);
2984  		goto coming_cleanup;
2985  	} else if (after_dashes) {
2986  		pr_warn("%s: parameters '%s' after `--' ignored\n",
2987  		       mod->name, after_dashes);
2988  	}
2989  
2990  	/* Link in to sysfs. */
2991  	err = mod_sysfs_setup(mod, info, mod->kp, mod->num_kp);
2992  	if (err < 0)
2993  		goto coming_cleanup;
2994  
2995  	if (is_livepatch_module(mod)) {
2996  		err = copy_module_elf(mod, info);
2997  		if (err < 0)
2998  			goto sysfs_cleanup;
2999  	}
3000  
3001  	/* Get rid of temporary copy. */
3002  	free_copy(info, flags);
3003  
3004  	codetag_load_module(mod);
3005  
3006  	/* Done! */
3007  	trace_module_load(mod);
3008  
3009  	return do_init_module(mod);
3010  
3011   sysfs_cleanup:
3012  	mod_sysfs_teardown(mod);
3013   coming_cleanup:
3014  	mod->state = MODULE_STATE_GOING;
3015  	destroy_params(mod->kp, mod->num_kp);
3016  	blocking_notifier_call_chain(&module_notify_list,
3017  				     MODULE_STATE_GOING, mod);
3018  	klp_module_going(mod);
3019   bug_cleanup:
3020  	mod->state = MODULE_STATE_GOING;
3021  	/* module_bug_cleanup needs module_mutex protection */
3022  	mutex_lock(&module_mutex);
3023  	module_bug_cleanup(mod);
3024  	mutex_unlock(&module_mutex);
3025  
3026   ddebug_cleanup:
3027  	ftrace_release_mod(mod);
3028  	synchronize_rcu();
3029  	kfree(mod->args);
3030   free_arch_cleanup:
3031  	module_arch_cleanup(mod);
3032   free_modinfo:
3033  	free_modinfo(mod);
3034   free_unload:
3035  	module_unload_free(mod);
3036   unlink_mod:
3037  	mutex_lock(&module_mutex);
3038  	/* Unlink carefully: kallsyms could be walking list. */
3039  	list_del_rcu(&mod->list);
3040  	mod_tree_remove(mod);
3041  	wake_up_all(&module_wq);
3042  	/* Wait for RCU-sched synchronizing before releasing mod->list. */
3043  	synchronize_rcu();
3044  	mutex_unlock(&module_mutex);
3045   free_module:
3046  	mod_stat_bump_invalid(info, flags);
3047  	/* Free lock-classes; relies on the preceding sync_rcu() */
3048  	for_class_mod_mem_type(type, core_data) {
3049  		lockdep_free_key_range(mod->mem[type].base,
3050  				       mod->mem[type].size);
3051  	}
3052  
3053  	module_deallocate(mod, info);
3054   free_copy:
3055  	/*
3056  	 * The info->len is always set. We distinguish between
3057  	 * failures once the proper module was allocated and
3058  	 * before that.
3059  	 */
3060  	if (!module_allocated)
3061  		mod_stat_bump_becoming(info, flags);
3062  	free_copy(info, flags);
3063  	return err;
3064  }
3065  
SYSCALL_DEFINE3(init_module,void __user *,umod,unsigned long,len,const char __user *,uargs)3066  SYSCALL_DEFINE3(init_module, void __user *, umod,
3067  		unsigned long, len, const char __user *, uargs)
3068  {
3069  	int err;
3070  	struct load_info info = { };
3071  
3072  	err = may_init_module();
3073  	if (err)
3074  		return err;
3075  
3076  	pr_debug("init_module: umod=%p, len=%lu, uargs=%p\n",
3077  	       umod, len, uargs);
3078  
3079  	err = copy_module_from_user(umod, len, &info);
3080  	if (err) {
3081  		mod_stat_inc(&failed_kreads);
3082  		mod_stat_add_long(len, &invalid_kread_bytes);
3083  		return err;
3084  	}
3085  
3086  	return load_module(&info, uargs, 0);
3087  }
3088  
3089  struct idempotent {
3090  	const void *cookie;
3091  	struct hlist_node entry;
3092  	struct completion complete;
3093  	int ret;
3094  };
3095  
3096  #define IDEM_HASH_BITS 8
3097  static struct hlist_head idem_hash[1 << IDEM_HASH_BITS];
3098  static DEFINE_SPINLOCK(idem_lock);
3099  
idempotent(struct idempotent * u,const void * cookie)3100  static bool idempotent(struct idempotent *u, const void *cookie)
3101  {
3102  	int hash = hash_ptr(cookie, IDEM_HASH_BITS);
3103  	struct hlist_head *head = idem_hash + hash;
3104  	struct idempotent *existing;
3105  	bool first;
3106  
3107  	u->ret = -EINTR;
3108  	u->cookie = cookie;
3109  	init_completion(&u->complete);
3110  
3111  	spin_lock(&idem_lock);
3112  	first = true;
3113  	hlist_for_each_entry(existing, head, entry) {
3114  		if (existing->cookie != cookie)
3115  			continue;
3116  		first = false;
3117  		break;
3118  	}
3119  	hlist_add_head(&u->entry, idem_hash + hash);
3120  	spin_unlock(&idem_lock);
3121  
3122  	return !first;
3123  }
3124  
3125  /*
3126   * We were the first one with 'cookie' on the list, and we ended
3127   * up completing the operation. We now need to walk the list,
3128   * remove everybody - which includes ourselves - fill in the return
3129   * value, and then complete the operation.
3130   */
idempotent_complete(struct idempotent * u,int ret)3131  static int idempotent_complete(struct idempotent *u, int ret)
3132  {
3133  	const void *cookie = u->cookie;
3134  	int hash = hash_ptr(cookie, IDEM_HASH_BITS);
3135  	struct hlist_head *head = idem_hash + hash;
3136  	struct hlist_node *next;
3137  	struct idempotent *pos;
3138  
3139  	spin_lock(&idem_lock);
3140  	hlist_for_each_entry_safe(pos, next, head, entry) {
3141  		if (pos->cookie != cookie)
3142  			continue;
3143  		hlist_del_init(&pos->entry);
3144  		pos->ret = ret;
3145  		complete(&pos->complete);
3146  	}
3147  	spin_unlock(&idem_lock);
3148  	return ret;
3149  }
3150  
3151  /*
3152   * Wait for the idempotent worker.
3153   *
3154   * If we get interrupted, we need to remove ourselves from the
3155   * the idempotent list, and the completion may still come in.
3156   *
3157   * The 'idem_lock' protects against the race, and 'idem.ret' was
3158   * initialized to -EINTR and is thus always the right return
3159   * value even if the idempotent work then completes between
3160   * the wait_for_completion and the cleanup.
3161   */
idempotent_wait_for_completion(struct idempotent * u)3162  static int idempotent_wait_for_completion(struct idempotent *u)
3163  {
3164  	if (wait_for_completion_interruptible(&u->complete)) {
3165  		spin_lock(&idem_lock);
3166  		if (!hlist_unhashed(&u->entry))
3167  			hlist_del(&u->entry);
3168  		spin_unlock(&idem_lock);
3169  	}
3170  	return u->ret;
3171  }
3172  
init_module_from_file(struct file * f,const char __user * uargs,int flags)3173  static int init_module_from_file(struct file *f, const char __user * uargs, int flags)
3174  {
3175  	struct load_info info = { };
3176  	void *buf = NULL;
3177  	int len;
3178  
3179  	len = kernel_read_file(f, 0, &buf, INT_MAX, NULL, READING_MODULE);
3180  	if (len < 0) {
3181  		mod_stat_inc(&failed_kreads);
3182  		return len;
3183  	}
3184  
3185  	if (flags & MODULE_INIT_COMPRESSED_FILE) {
3186  		int err = module_decompress(&info, buf, len);
3187  		vfree(buf); /* compressed data is no longer needed */
3188  		if (err) {
3189  			mod_stat_inc(&failed_decompress);
3190  			mod_stat_add_long(len, &invalid_decompress_bytes);
3191  			return err;
3192  		}
3193  	} else {
3194  		info.hdr = buf;
3195  		info.len = len;
3196  	}
3197  
3198  	return load_module(&info, uargs, flags);
3199  }
3200  
idempotent_init_module(struct file * f,const char __user * uargs,int flags)3201  static int idempotent_init_module(struct file *f, const char __user * uargs, int flags)
3202  {
3203  	struct idempotent idem;
3204  
3205  	if (!f || !(f->f_mode & FMODE_READ))
3206  		return -EBADF;
3207  
3208  	/* Are we the winners of the race and get to do this? */
3209  	if (!idempotent(&idem, file_inode(f))) {
3210  		int ret = init_module_from_file(f, uargs, flags);
3211  		return idempotent_complete(&idem, ret);
3212  	}
3213  
3214  	/*
3215  	 * Somebody else won the race and is loading the module.
3216  	 */
3217  	return idempotent_wait_for_completion(&idem);
3218  }
3219  
SYSCALL_DEFINE3(finit_module,int,fd,const char __user *,uargs,int,flags)3220  SYSCALL_DEFINE3(finit_module, int, fd, const char __user *, uargs, int, flags)
3221  {
3222  	int err;
3223  	struct fd f;
3224  
3225  	err = may_init_module();
3226  	if (err)
3227  		return err;
3228  
3229  	pr_debug("finit_module: fd=%d, uargs=%p, flags=%i\n", fd, uargs, flags);
3230  
3231  	if (flags & ~(MODULE_INIT_IGNORE_MODVERSIONS
3232  		      |MODULE_INIT_IGNORE_VERMAGIC
3233  		      |MODULE_INIT_COMPRESSED_FILE))
3234  		return -EINVAL;
3235  
3236  	f = fdget(fd);
3237  	err = idempotent_init_module(fd_file(f), uargs, flags);
3238  	fdput(f);
3239  	return err;
3240  }
3241  
3242  /* Keep in sync with MODULE_FLAGS_BUF_SIZE !!! */
module_flags(struct module * mod,char * buf,bool show_state)3243  char *module_flags(struct module *mod, char *buf, bool show_state)
3244  {
3245  	int bx = 0;
3246  
3247  	BUG_ON(mod->state == MODULE_STATE_UNFORMED);
3248  	if (!mod->taints && !show_state)
3249  		goto out;
3250  	if (mod->taints ||
3251  	    mod->state == MODULE_STATE_GOING ||
3252  	    mod->state == MODULE_STATE_COMING) {
3253  		buf[bx++] = '(';
3254  		bx += module_flags_taint(mod->taints, buf + bx);
3255  		/* Show a - for module-is-being-unloaded */
3256  		if (mod->state == MODULE_STATE_GOING && show_state)
3257  			buf[bx++] = '-';
3258  		/* Show a + for module-is-being-loaded */
3259  		if (mod->state == MODULE_STATE_COMING && show_state)
3260  			buf[bx++] = '+';
3261  		buf[bx++] = ')';
3262  	}
3263  out:
3264  	buf[bx] = '\0';
3265  
3266  	return buf;
3267  }
3268  
3269  /* Given an address, look for it in the module exception tables. */
search_module_extables(unsigned long addr)3270  const struct exception_table_entry *search_module_extables(unsigned long addr)
3271  {
3272  	const struct exception_table_entry *e = NULL;
3273  	struct module *mod;
3274  
3275  	preempt_disable();
3276  	mod = __module_address(addr);
3277  	if (!mod)
3278  		goto out;
3279  
3280  	if (!mod->num_exentries)
3281  		goto out;
3282  
3283  	e = search_extable(mod->extable,
3284  			   mod->num_exentries,
3285  			   addr);
3286  out:
3287  	preempt_enable();
3288  
3289  	/*
3290  	 * Now, if we found one, we are running inside it now, hence
3291  	 * we cannot unload the module, hence no refcnt needed.
3292  	 */
3293  	return e;
3294  }
3295  
3296  /**
3297   * is_module_address() - is this address inside a module?
3298   * @addr: the address to check.
3299   *
3300   * See is_module_text_address() if you simply want to see if the address
3301   * is code (not data).
3302   */
is_module_address(unsigned long addr)3303  bool is_module_address(unsigned long addr)
3304  {
3305  	bool ret;
3306  
3307  	preempt_disable();
3308  	ret = __module_address(addr) != NULL;
3309  	preempt_enable();
3310  
3311  	return ret;
3312  }
3313  
3314  /**
3315   * __module_address() - get the module which contains an address.
3316   * @addr: the address.
3317   *
3318   * Must be called with preempt disabled or module mutex held so that
3319   * module doesn't get freed during this.
3320   */
__module_address(unsigned long addr)3321  struct module *__module_address(unsigned long addr)
3322  {
3323  	struct module *mod;
3324  
3325  	if (addr >= mod_tree.addr_min && addr <= mod_tree.addr_max)
3326  		goto lookup;
3327  
3328  #ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
3329  	if (addr >= mod_tree.data_addr_min && addr <= mod_tree.data_addr_max)
3330  		goto lookup;
3331  #endif
3332  
3333  	return NULL;
3334  
3335  lookup:
3336  	module_assert_mutex_or_preempt();
3337  
3338  	mod = mod_find(addr, &mod_tree);
3339  	if (mod) {
3340  		BUG_ON(!within_module(addr, mod));
3341  		if (mod->state == MODULE_STATE_UNFORMED)
3342  			mod = NULL;
3343  	}
3344  	return mod;
3345  }
3346  
3347  /**
3348   * is_module_text_address() - is this address inside module code?
3349   * @addr: the address to check.
3350   *
3351   * See is_module_address() if you simply want to see if the address is
3352   * anywhere in a module.  See kernel_text_address() for testing if an
3353   * address corresponds to kernel or module code.
3354   */
is_module_text_address(unsigned long addr)3355  bool is_module_text_address(unsigned long addr)
3356  {
3357  	bool ret;
3358  
3359  	preempt_disable();
3360  	ret = __module_text_address(addr) != NULL;
3361  	preempt_enable();
3362  
3363  	return ret;
3364  }
3365  
3366  /**
3367   * __module_text_address() - get the module whose code contains an address.
3368   * @addr: the address.
3369   *
3370   * Must be called with preempt disabled or module mutex held so that
3371   * module doesn't get freed during this.
3372   */
__module_text_address(unsigned long addr)3373  struct module *__module_text_address(unsigned long addr)
3374  {
3375  	struct module *mod = __module_address(addr);
3376  	if (mod) {
3377  		/* Make sure it's within the text section. */
3378  		if (!within_module_mem_type(addr, mod, MOD_TEXT) &&
3379  		    !within_module_mem_type(addr, mod, MOD_INIT_TEXT))
3380  			mod = NULL;
3381  	}
3382  	return mod;
3383  }
3384  
3385  /* Don't grab lock, we're oopsing. */
print_modules(void)3386  void print_modules(void)
3387  {
3388  	struct module *mod;
3389  	char buf[MODULE_FLAGS_BUF_SIZE];
3390  
3391  	printk(KERN_DEFAULT "Modules linked in:");
3392  	/* Most callers should already have preempt disabled, but make sure */
3393  	preempt_disable();
3394  	list_for_each_entry_rcu(mod, &modules, list) {
3395  		if (mod->state == MODULE_STATE_UNFORMED)
3396  			continue;
3397  		pr_cont(" %s%s", mod->name, module_flags(mod, buf, true));
3398  	}
3399  
3400  	print_unloaded_tainted_modules();
3401  	preempt_enable();
3402  	if (last_unloaded_module.name[0])
3403  		pr_cont(" [last unloaded: %s%s]", last_unloaded_module.name,
3404  			last_unloaded_module.taints);
3405  	pr_cont("\n");
3406  }
3407  
3408  #ifdef CONFIG_MODULE_DEBUGFS
3409  struct dentry *mod_debugfs_root;
3410  
module_debugfs_init(void)3411  static int module_debugfs_init(void)
3412  {
3413  	mod_debugfs_root = debugfs_create_dir("modules", NULL);
3414  	return 0;
3415  }
3416  module_init(module_debugfs_init);
3417  #endif
3418