module.c 97.5 KB
Newer Older
1
/*
Linus Torvalds's avatar
Linus Torvalds committed
2
   Copyright (C) 2002 Richard Henderson
3
   Copyright (C) 2001 Rusty Russell, 2002, 2010 Rusty Russell IBM.
Linus Torvalds's avatar
Linus Torvalds committed
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/
19
#include <linux/export.h>
Linus Torvalds's avatar
Linus Torvalds committed
20
#include <linux/moduleloader.h>
21
#include <linux/ftrace_event.h>
Linus Torvalds's avatar
Linus Torvalds committed
22
#include <linux/init.h>
23
#include <linux/kallsyms.h>
24
#include <linux/file.h>
25
#include <linux/fs.h>
Roland McGrath's avatar
Roland McGrath committed
26
#include <linux/sysfs.h>
27
#include <linux/kernel.h>
Linus Torvalds's avatar
Linus Torvalds committed
28 29 30
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/elf.h>
31
#include <linux/proc_fs.h>
32
#include <linux/security.h>
Linus Torvalds's avatar
Linus Torvalds committed
33 34 35 36
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/fcntl.h>
#include <linux/rcupdate.h>
37
#include <linux/capability.h>
Linus Torvalds's avatar
Linus Torvalds committed
38 39 40 41 42 43
#include <linux/cpu.h>
#include <linux/moduleparam.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/vermagic.h>
#include <linux/notifier.h>
Al Viro's avatar
Al Viro committed
44
#include <linux/sched.h>
Linus Torvalds's avatar
Linus Torvalds committed
45 46
#include <linux/stop_machine.h>
#include <linux/device.h>
47
#include <linux/string.h>
48
#include <linux/mutex.h>
49
#include <linux/rculist.h>
Linus Torvalds's avatar
Linus Torvalds committed
50 51
#include <asm/uaccess.h>
#include <asm/cacheflush.h>
52
#include <asm/mmu_context.h>
53
#include <linux/license.h>
54
#include <asm/sections.h>
55
#include <linux/tracepoint.h>
56
#include <linux/ftrace.h>
57
#include <linux/async.h>
58
#include <linux/percpu.h>
59
#include <linux/kmemleak.h>
60
#include <linux/jump_label.h>
61
#include <linux/pfn.h>
62
#include <linux/bsearch.h>
David Howells's avatar
David Howells committed
63
#include <linux/fips.h>
64
#include <uapi/linux/module.h>
65
#include "module-internal.h"
Linus Torvalds's avatar
Linus Torvalds committed
66

67 68 69
#define CREATE_TRACE_POINTS
#include <trace/events/module.h>

Linus Torvalds's avatar
Linus Torvalds committed
70 71 72 73
#ifndef ARCH_SHF_SMALL
#define ARCH_SHF_SMALL 0
#endif

74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93
/*
 * Modules' sections will be aligned on page boundaries
 * to ensure complete separation of code and data, but
 * only when CONFIG_DEBUG_SET_MODULE_RONX=y
 */
#ifdef CONFIG_DEBUG_SET_MODULE_RONX
# define debug_align(X) ALIGN(X, PAGE_SIZE)
#else
# define debug_align(X) (X)
#endif

/*
 * Given BASE and SIZE this macro calculates the number of pages the
 * memory regions occupies
 */
#define MOD_NUMBER_OF_PAGES(BASE, SIZE) (((SIZE) > 0) ?		\
		(PFN_DOWN((unsigned long)(BASE) + (SIZE) - 1) -	\
			 PFN_DOWN((unsigned long)BASE) + 1)	\
		: (0UL))

Linus Torvalds's avatar
Linus Torvalds committed
94 95 96
/* If this is set, the section belongs in the init part of the module */
#define INIT_OFFSET_MASK (1UL << (BITS_PER_LONG-1))

97 98 99 100 101
/*
 * Mutex protects:
 * 1) List of modules (also safely readable with preempt_disable),
 * 2) module_use links,
 * 3) module_addr_min/module_addr_max.
102
 * (delete uses stop_machine/add uses RCU list operations). */
103 104
DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
105
static LIST_HEAD(modules);
106 107 108 109
#ifdef CONFIG_KGDB_KDB
struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
#endif /* CONFIG_KGDB_KDB */

110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146
#ifdef CONFIG_MODULE_SIG
#ifdef CONFIG_MODULE_SIG_FORCE
static bool sig_enforce = true;
#else
static bool sig_enforce = false;

static int param_set_bool_enable_only(const char *val,
				      const struct kernel_param *kp)
{
	int err;
	bool test;
	struct kernel_param dummy_kp = *kp;

	dummy_kp.arg = &test;

	err = param_set_bool(val, &dummy_kp);
	if (err)
		return err;

	/* Don't let them unset it once it's set! */
	if (!test && sig_enforce)
		return -EROFS;

	if (test)
		sig_enforce = true;
	return 0;
}

static const struct kernel_param_ops param_ops_bool_enable_only = {
	.set = param_set_bool_enable_only,
	.get = param_get_bool,
};
#define param_check_bool_enable_only param_check_bool

module_param(sig_enforce, bool_enable_only, 0644);
#endif /* !CONFIG_MODULE_SIG_FORCE */
#endif /* CONFIG_MODULE_SIG */
Linus Torvalds's avatar
Linus Torvalds committed
147

148 149
/* Block module loading/unloading? */
int modules_disabled = 0;
150
core_param(nomodule, modules_disabled, bint, 0);
151

152 153 154
/* Waiting for a module to finish initializing? */
static DECLARE_WAIT_QUEUE_HEAD(module_wq);

155
static BLOCKING_NOTIFIER_HEAD(module_notify_list);
Linus Torvalds's avatar
Linus Torvalds committed
156

157 158
/* Bounds of module allocation, for speeding __module_address.
 * Protected by module_mutex. */
159 160
static unsigned long module_addr_min = -1UL, module_addr_max = 0;

Linus Torvalds's avatar
Linus Torvalds committed
161 162
int register_module_notifier(struct notifier_block * nb)
{
163
	return blocking_notifier_chain_register(&module_notify_list, nb);
Linus Torvalds's avatar
Linus Torvalds committed
164 165 166 167 168
}
EXPORT_SYMBOL(register_module_notifier);

int unregister_module_notifier(struct notifier_block * nb)
{
169
	return blocking_notifier_chain_unregister(&module_notify_list, nb);
Linus Torvalds's avatar
Linus Torvalds committed
170 171 172
}
EXPORT_SYMBOL(unregister_module_notifier);

173 174 175 176
struct load_info {
	Elf_Ehdr *hdr;
	unsigned long len;
	Elf_Shdr *sechdrs;
177
	char *secstrings, *strtab;
Rusty Russell's avatar
Rusty Russell committed
178
	unsigned long symoffs, stroffs;
179 180
	struct _ddebug *debug;
	unsigned int num_debug;
181
	bool sig_ok;
182 183 184 185 186
	struct {
		unsigned int sym, str, mod, vers, info, pcpu;
	} index;
};

187 188
/* We require a truly strong try_module_get(): 0 means failure due to
   ongoing or failed initialization etc. */
Linus Torvalds's avatar
Linus Torvalds committed
189 190
static inline int strong_try_module_get(struct module *mod)
{
191
	BUG_ON(mod && mod->state == MODULE_STATE_UNFORMED);
Linus Torvalds's avatar
Linus Torvalds committed
192
	if (mod && mod->state == MODULE_STATE_COMING)
193 194
		return -EBUSY;
	if (try_module_get(mod))
Linus Torvalds's avatar
Linus Torvalds committed
195
		return 0;
196 197
	else
		return -ENOENT;
Linus Torvalds's avatar
Linus Torvalds committed
198 199
}

200 201
static inline void add_taint_module(struct module *mod, unsigned flag,
				    enum lockdep_ok lockdep_ok)
202
{
203
	add_taint(flag, lockdep_ok);
Andi Kleen's avatar
Andi Kleen committed
204
	mod->taints |= (1U << flag);
205 206
}

207 208 209
/*
 * A thread that wants to hold a reference to a module only while it
 * is running can call this to safely exit.  nfsd and lockd use this.
Linus Torvalds's avatar
Linus Torvalds committed
210 211 212 213 214 215 216
 */
void __module_put_and_exit(struct module *mod, long code)
{
	module_put(mod);
	do_exit(code);
}
EXPORT_SYMBOL(__module_put_and_exit);
217

Linus Torvalds's avatar
Linus Torvalds committed
218
/* Find a module section: 0 means not found. */
219
static unsigned int find_sec(const struct load_info *info, const char *name)
Linus Torvalds's avatar
Linus Torvalds committed
220 221 222
{
	unsigned int i;

223 224
	for (i = 1; i < info->hdr->e_shnum; i++) {
		Elf_Shdr *shdr = &info->sechdrs[i];
Linus Torvalds's avatar
Linus Torvalds committed
225
		/* Alloc bit cleared means "ignore it." */
226 227
		if ((shdr->sh_flags & SHF_ALLOC)
		    && strcmp(info->secstrings + shdr->sh_name, name) == 0)
Linus Torvalds's avatar
Linus Torvalds committed
228
			return i;
229
	}
Linus Torvalds's avatar
Linus Torvalds committed
230 231 232
	return 0;
}

233
/* Find a module section, or NULL. */
234
static void *section_addr(const struct load_info *info, const char *name)
235 236
{
	/* Section 0 has sh_addr 0. */
237
	return (void *)info->sechdrs[find_sec(info, name)].sh_addr;
238 239 240
}

/* Find a module section, or NULL.  Fill in number of "objects" in section. */
241
static void *section_objs(const struct load_info *info,
242 243 244 245
			  const char *name,
			  size_t object_size,
			  unsigned int *num)
{
246
	unsigned int sec = find_sec(info, name);
247 248

	/* Section 0 has sh_addr 0 and sh_size 0. */
249 250
	*num = info->sechdrs[sec].sh_size / object_size;
	return (void *)info->sechdrs[sec].sh_addr;
251 252
}

Linus Torvalds's avatar
Linus Torvalds committed
253 254 255 256 257
/* Provided by the linker */
extern const struct kernel_symbol __start___ksymtab[];
extern const struct kernel_symbol __stop___ksymtab[];
extern const struct kernel_symbol __start___ksymtab_gpl[];
extern const struct kernel_symbol __stop___ksymtab_gpl[];
258 259
extern const struct kernel_symbol __start___ksymtab_gpl_future[];
extern const struct kernel_symbol __stop___ksymtab_gpl_future[];
Linus Torvalds's avatar
Linus Torvalds committed
260 261
extern const unsigned long __start___kcrctab[];
extern const unsigned long __start___kcrctab_gpl[];
262
extern const unsigned long __start___kcrctab_gpl_future[];
263 264 265 266 267
#ifdef CONFIG_UNUSED_SYMBOLS
extern const struct kernel_symbol __start___ksymtab_unused[];
extern const struct kernel_symbol __stop___ksymtab_unused[];
extern const struct kernel_symbol __start___ksymtab_unused_gpl[];
extern const struct kernel_symbol __stop___ksymtab_unused_gpl[];
268 269
extern const unsigned long __start___kcrctab_unused[];
extern const unsigned long __start___kcrctab_unused_gpl[];
270
#endif
Linus Torvalds's avatar
Linus Torvalds committed
271 272 273 274

#ifndef CONFIG_MODVERSIONS
#define symversion(base, idx) NULL
#else
275
#define symversion(base, idx) ((base != NULL) ? ((base) + (idx)) : NULL)
Linus Torvalds's avatar
Linus Torvalds committed
276 277
#endif

278 279 280 281 282
static bool each_symbol_in_section(const struct symsearch *arr,
				   unsigned int arrsize,
				   struct module *owner,
				   bool (*fn)(const struct symsearch *syms,
					      struct module *owner,
283
					      void *data),
284
				   void *data)
285
{
286
	unsigned int j;
287

288
	for (j = 0; j < arrsize; j++) {
289 290
		if (fn(&arr[j], owner, data))
			return true;
291
	}
292 293

	return false;
294 295
}

296
/* Returns true as soon as fn returns true, otherwise false. */
297 298 299 300
bool each_symbol_section(bool (*fn)(const struct symsearch *arr,
				    struct module *owner,
				    void *data),
			 void *data)
301 302
{
	struct module *mod;
303
	static const struct symsearch arr[] = {
304
		{ __start___ksymtab, __stop___ksymtab, __start___kcrctab,
305
		  NOT_GPL_ONLY, false },
306
		{ __start___ksymtab_gpl, __stop___ksymtab_gpl,
307 308
		  __start___kcrctab_gpl,
		  GPL_ONLY, false },
309
		{ __start___ksymtab_gpl_future, __stop___ksymtab_gpl_future,
310 311
		  __start___kcrctab_gpl_future,
		  WILL_BE_GPL_ONLY, false },
312
#ifdef CONFIG_UNUSED_SYMBOLS
313
		{ __start___ksymtab_unused, __stop___ksymtab_unused,
314 315
		  __start___kcrctab_unused,
		  NOT_GPL_ONLY, true },
316
		{ __start___ksymtab_unused_gpl, __stop___ksymtab_unused_gpl,
317 318
		  __start___kcrctab_unused_gpl,
		  GPL_ONLY, true },
319
#endif
320
	};
321

322 323
	if (each_symbol_in_section(arr, ARRAY_SIZE(arr), NULL, fn, data))
		return true;
324

325
	list_for_each_entry_rcu(mod, &modules, list) {
326 327
		struct symsearch arr[] = {
			{ mod->syms, mod->syms + mod->num_syms, mod->crcs,
328
			  NOT_GPL_ONLY, false },
329
			{ mod->gpl_syms, mod->gpl_syms + mod->num_gpl_syms,
330 331
			  mod->gpl_crcs,
			  GPL_ONLY, false },
332 333
			{ mod->gpl_future_syms,
			  mod->gpl_future_syms + mod->num_gpl_future_syms,
334 335
			  mod->gpl_future_crcs,
			  WILL_BE_GPL_ONLY, false },
336
#ifdef CONFIG_UNUSED_SYMBOLS
337 338
			{ mod->unused_syms,
			  mod->unused_syms + mod->num_unused_syms,
339 340
			  mod->unused_crcs,
			  NOT_GPL_ONLY, true },
341 342
			{ mod->unused_gpl_syms,
			  mod->unused_gpl_syms + mod->num_unused_gpl_syms,
343 344
			  mod->unused_gpl_crcs,
			  GPL_ONLY, true },
345
#endif
346 347
		};

348 349 350
		if (mod->state == MODULE_STATE_UNFORMED)
			continue;

351 352 353 354 355
		if (each_symbol_in_section(arr, ARRAY_SIZE(arr), mod, fn, data))
			return true;
	}
	return false;
}
356
EXPORT_SYMBOL_GPL(each_symbol_section);
357 358 359 360 361 362 363 364 365 366

struct find_symbol_arg {
	/* Input */
	const char *name;
	bool gplok;
	bool warn;

	/* Output */
	struct module *owner;
	const unsigned long *crc;
367
	const struct kernel_symbol *sym;
368 369
};

370 371 372
static bool check_symbol(const struct symsearch *syms,
				 struct module *owner,
				 unsigned int symnum, void *data)
373 374 375 376 377 378 379 380 381 382
{
	struct find_symbol_arg *fsa = data;

	if (!fsa->gplok) {
		if (syms->licence == GPL_ONLY)
			return false;
		if (syms->licence == WILL_BE_GPL_ONLY && fsa->warn) {
			printk(KERN_WARNING "Symbol %s is being used "
			       "by a non-GPL module, which will not "
			       "be allowed in the future\n", fsa->name);
383
		}
Linus Torvalds's avatar
Linus Torvalds committed
384
	}
385

386
#ifdef CONFIG_UNUSED_SYMBOLS
387 388 389 390 391 392 393 394 395 396 397
	if (syms->unused && fsa->warn) {
		printk(KERN_WARNING "Symbol %s is marked as UNUSED, "
		       "however this module is using it.\n", fsa->name);
		printk(KERN_WARNING
		       "This symbol will go away in the future.\n");
		printk(KERN_WARNING
		       "Please evalute if this is the right api to use and if "
		       "it really is, submit a report the linux kernel "
		       "mailinglist together with submitting your code for "
		       "inclusion.\n");
	}
398
#endif
399 400 401

	fsa->owner = owner;
	fsa->crc = symversion(syms->crcs, symnum);
402
	fsa->sym = &syms->start[symnum];
403 404 405
	return true;
}

406 407 408 409 410 411 412 413
static int cmp_name(const void *va, const void *vb)
{
	const char *a;
	const struct kernel_symbol *b;
	a = va; b = vb;
	return strcmp(a, b->name);
}

414 415 416 417 418
static bool find_symbol_in_section(const struct symsearch *syms,
				   struct module *owner,
				   void *data)
{
	struct find_symbol_arg *fsa = data;
419 420 421 422 423 424 425
	struct kernel_symbol *sym;

	sym = bsearch(fsa->name, syms->start, syms->stop - syms->start,
			sizeof(struct kernel_symbol), cmp_name);

	if (sym != NULL && check_symbol(syms, owner, sym - syms->start, data))
		return true;
426 427 428 429

	return false;
}

430
/* Find a symbol and return it, along with, (optional) crc and
431
 * (optional) module which owns it.  Needs preempt disabled or module_mutex. */
432 433 434 435 436
const struct kernel_symbol *find_symbol(const char *name,
					struct module **owner,
					const unsigned long **crc,
					bool gplok,
					bool warn)
437 438 439 440 441 442 443
{
	struct find_symbol_arg fsa;

	fsa.name = name;
	fsa.gplok = gplok;
	fsa.warn = warn;

444
	if (each_symbol_section(find_symbol_in_section, &fsa)) {
445 446 447 448
		if (owner)
			*owner = fsa.owner;
		if (crc)
			*crc = fsa.crc;
449
		return fsa.sym;
450 451
	}

452
	pr_debug("Failed to find symbol %s\n", name);
453
	return NULL;
Linus Torvalds's avatar
Linus Torvalds committed
454
}
455
EXPORT_SYMBOL_GPL(find_symbol);
Linus Torvalds's avatar
Linus Torvalds committed
456 457

/* Search for module by name: must hold module_mutex. */
458
static struct module *find_module_all(const char *name, size_t len,
459
				      bool even_unformed)
Linus Torvalds's avatar
Linus Torvalds committed
460 461 462 463
{
	struct module *mod;

	list_for_each_entry(mod, &modules, list) {
464 465
		if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
			continue;
466
		if (strlen(mod->name) == len && !memcmp(mod->name, name, len))
Linus Torvalds's avatar
Linus Torvalds committed
467 468 469 470
			return mod;
	}
	return NULL;
}
471 472 473

struct module *find_module(const char *name)
{
474
	return find_module_all(name, strlen(name), false);
475
}
476
EXPORT_SYMBOL_GPL(find_module);
Linus Torvalds's avatar
Linus Torvalds committed
477 478

#ifdef CONFIG_SMP
479

480
static inline void __percpu *mod_percpu(struct module *mod)
481
{
482 483
	return mod->percpu;
}
484

485 486 487
static int percpu_modalloc(struct module *mod,
			   unsigned long size, unsigned long align)
{
488 489
	if (align > PAGE_SIZE) {
		printk(KERN_WARNING "%s: per-cpu alignment %li > %li\n",
490
		       mod->name, align, PAGE_SIZE);
491 492 493
		align = PAGE_SIZE;
	}

494 495
	mod->percpu = __alloc_reserved_percpu(size, align);
	if (!mod->percpu) {
496
		printk(KERN_WARNING
Rusty Russell's avatar
Rusty Russell committed
497 498
		       "%s: Could not allocate %lu bytes percpu data\n",
		       mod->name, size);
499 500 501 502
		return -ENOMEM;
	}
	mod->percpu_size = size;
	return 0;
503 504
}

505
static void percpu_modfree(struct module *mod)
506
{
507
	free_percpu(mod->percpu);
508 509
}

510
static unsigned int find_pcpusec(struct load_info *info)
511
{
512
	return find_sec(info, ".data..percpu");
513 514
}

515 516
static void percpu_modcopy(struct module *mod,
			   const void *from, unsigned long size)
517 518 519 520
{
	int cpu;

	for_each_possible_cpu(cpu)
521
		memcpy(per_cpu_ptr(mod->percpu, cpu), from, size);
522 523
}

524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540
/**
 * is_module_percpu_address - test whether address is from module static percpu
 * @addr: address to test
 *
 * Test whether @addr belongs to module static percpu area.
 *
 * RETURNS:
 * %true if @addr is from module static percpu area
 */
bool is_module_percpu_address(unsigned long addr)
{
	struct module *mod;
	unsigned int cpu;

	preempt_disable();

	list_for_each_entry_rcu(mod, &modules, list) {
541 542
		if (mod->state == MODULE_STATE_UNFORMED)
			continue;
543 544 545 546 547 548 549 550 551 552 553 554 555 556 557
		if (!mod->percpu_size)
			continue;
		for_each_possible_cpu(cpu) {
			void *start = per_cpu_ptr(mod->percpu, cpu);

			if ((void *)addr >= start &&
			    (void *)addr < start + mod->percpu_size) {
				preempt_enable();
				return true;
			}
		}
	}

	preempt_enable();
	return false;
558 559
}

Linus Torvalds's avatar
Linus Torvalds committed
560
#else /* ... !CONFIG_SMP */
561

562
static inline void __percpu *mod_percpu(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
563 564 565
{
	return NULL;
}
566 567 568 569 570 571
static inline int percpu_modalloc(struct module *mod,
				  unsigned long size, unsigned long align)
{
	return -ENOMEM;
}
static inline void percpu_modfree(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
572 573
{
}
574
static unsigned int find_pcpusec(struct load_info *info)
Linus Torvalds's avatar
Linus Torvalds committed
575 576 577
{
	return 0;
}
578 579
static inline void percpu_modcopy(struct module *mod,
				  const void *from, unsigned long size)
Linus Torvalds's avatar
Linus Torvalds committed
580 581 582 583
{
	/* pcpusec should be 0, and size of that section should be 0. */
	BUG_ON(size != 0);
}
584 585 586 587
bool is_module_percpu_address(unsigned long addr)
{
	return false;
}
588

Linus Torvalds's avatar
Linus Torvalds committed
589 590
#endif /* CONFIG_SMP */

591 592 593 594 595 596
#define MODINFO_ATTR(field)	\
static void setup_modinfo_##field(struct module *mod, const char *s)  \
{                                                                     \
	mod->field = kstrdup(s, GFP_KERNEL);                          \
}                                                                     \
static ssize_t show_modinfo_##field(struct module_attribute *mattr,   \
597
			struct module_kobject *mk, char *buffer)      \
598
{                                                                     \
599
	return sprintf(buffer, "%s\n", mk->mod->field);               \
600 601 602 603 604 605 606
}                                                                     \
static int modinfo_##field##_exists(struct module *mod)               \
{                                                                     \
	return mod->field != NULL;                                    \
}                                                                     \
static void free_modinfo_##field(struct module *mod)                  \
{                                                                     \
607 608
	kfree(mod->field);                                            \
	mod->field = NULL;                                            \
609 610
}                                                                     \
static struct module_attribute modinfo_##field = {                    \
611
	.attr = { .name = __stringify(field), .mode = 0444 },         \
612 613 614 615 616 617 618 619 620
	.show = show_modinfo_##field,                                 \
	.setup = setup_modinfo_##field,                               \
	.test = modinfo_##field##_exists,                             \
	.free = free_modinfo_##field,                                 \
};

MODINFO_ATTR(version);
MODINFO_ATTR(srcversion);

621 622
static char last_unloaded_module[MODULE_NAME_LEN+1];

623
#ifdef CONFIG_MODULE_UNLOAD
624 625 626

EXPORT_TRACEPOINT_SYMBOL(module_get);

Linus Torvalds's avatar
Linus Torvalds committed
627
/* Init the unload section of the module. */
628
static int module_unload_init(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
629
{
630 631 632 633
	mod->refptr = alloc_percpu(struct module_ref);
	if (!mod->refptr)
		return -ENOMEM;

634 635
	INIT_LIST_HEAD(&mod->source_list);
	INIT_LIST_HEAD(&mod->target_list);
636

Linus Torvalds's avatar
Linus Torvalds committed
637
	/* Hold reference count during initialization. */
638
	__this_cpu_write(mod->refptr->incs, 1);
Linus Torvalds's avatar
Linus Torvalds committed
639 640
	/* Backwards compatibility macros put refcount during init. */
	mod->waiter = current;
641 642

	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
643 644 645 646 647 648 649
}

/* Does a already use b? */
static int already_uses(struct module *a, struct module *b)
{
	struct module_use *use;

650 651
	list_for_each_entry(use, &b->source_list, source_list) {
		if (use->source == a) {
652
			pr_debug("%s uses %s!\n", a->name, b->name);
Linus Torvalds's avatar
Linus Torvalds committed
653 654 655
			return 1;
		}
	}
656
	pr_debug("%s does not use %s!\n", a->name, b->name);
Linus Torvalds's avatar
Linus Torvalds committed
657 658 659
	return 0;
}

660 661 662 663 664 665 666 667 668 669 670
/*
 * Module a uses b
 *  - we add 'a' as a "source", 'b' as a "target" of module use
 *  - the module_use is added to the list of 'b' sources (so
 *    'b' can walk the list to see who sourced them), and of 'a'
 *    targets (so 'a' can see what modules it targets).
 */
static int add_module_usage(struct module *a, struct module *b)
{
	struct module_use *use;

671
	pr_debug("Allocating new usage for %s.\n", a->name);
672 673 674 675 676 677 678 679 680 681 682 683 684
	use = kmalloc(sizeof(*use), GFP_ATOMIC);
	if (!use) {
		printk(KERN_WARNING "%s: out of memory loading\n", a->name);
		return -ENOMEM;
	}

	use->source = a;
	use->target = b;
	list_add(&use->source_list, &b->source_list);
	list_add(&use->target_list, &a->target_list);
	return 0;
}

685
/* Module a uses b: caller needs module_mutex() */
686
int ref_module(struct module *a, struct module *b)
Linus Torvalds's avatar
Linus Torvalds committed
687
{
688
	int err;
Kay Sievers's avatar
Kay Sievers committed
689

690
	if (b == NULL || already_uses(a, b))
691 692
		return 0;

693 694
	/* If module isn't available, we fail. */
	err = strong_try_module_get(b);
695
	if (err)
696
		return err;
Linus Torvalds's avatar
Linus Torvalds committed
697

698 699
	err = add_module_usage(a, b);
	if (err) {
Linus Torvalds's avatar
Linus Torvalds committed
700
		module_put(b);
701
		return err;
Linus Torvalds's avatar
Linus Torvalds committed
702
	}
703
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
704
}
705
EXPORT_SYMBOL_GPL(ref_module);
Linus Torvalds's avatar
Linus Torvalds committed
706 707 708 709

/* Clear the unload stuff of the module. */
static void module_unload_free(struct module *mod)
{
710
	struct module_use *use, *tmp;
Linus Torvalds's avatar
Linus Torvalds committed
711

712
	mutex_lock(&module_mutex);
713 714
	list_for_each_entry_safe(use, tmp, &mod->target_list, target_list) {
		struct module *i = use->target;
715
		pr_debug("%s unusing %s\n", mod->name, i->name);
716 717 718 719
		module_put(i);
		list_del(&use->source_list);
		list_del(&use->target_list);
		kfree(use);
Linus Torvalds's avatar
Linus Torvalds committed
720
	}
721
	mutex_unlock(&module_mutex);
722 723

	free_percpu(mod->refptr);
Linus Torvalds's avatar
Linus Torvalds committed
724 725 726
}

#ifdef CONFIG_MODULE_FORCE_UNLOAD
727
static inline int try_force_unload(unsigned int flags)
Linus Torvalds's avatar
Linus Torvalds committed
728 729 730
{
	int ret = (flags & O_TRUNC);
	if (ret)
731
		add_taint(TAINT_FORCED_RMMOD, LOCKDEP_NOW_UNRELIABLE);
Linus Torvalds's avatar
Linus Torvalds committed
732 733 734
	return ret;
}
#else
735
static inline int try_force_unload(unsigned int flags)
Linus Torvalds's avatar
Linus Torvalds committed
736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752
{
	return 0;
}
#endif /* CONFIG_MODULE_FORCE_UNLOAD */

struct stopref
{
	struct module *mod;
	int flags;
	int *forced;
};

/* Whole machine is stopped with interrupts off when this runs. */
static int __try_stop_module(void *_sref)
{
	struct stopref *sref = _sref;

753 754
	/* If it's not unused, quit unless we're forcing. */
	if (module_refcount(sref->mod) != 0) {
755
		if (!(*sref->forced = try_force_unload(sref->flags)))
Linus Torvalds's avatar
Linus Torvalds committed
756 757 758 759 760 761 762 763 764 765
			return -EWOULDBLOCK;
	}

	/* Mark it as dying. */
	sref->mod->state = MODULE_STATE_GOING;
	return 0;
}

static int try_stop_module(struct module *mod, int flags, int *forced)
{
766 767
	if (flags & O_NONBLOCK) {
		struct stopref sref = { mod, flags, forced };
Linus Torvalds's avatar
Linus Torvalds committed
768

769
		return stop_machine(__try_stop_module, &sref, NULL);
770 771 772 773 774 775
	} else {
		/* We don't need to stop the machine for this. */
		mod->state = MODULE_STATE_GOING;
		synchronize_sched();
		return 0;
	}
Linus Torvalds's avatar
Linus Torvalds committed
776 777
}

778
unsigned long module_refcount(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
779
{
780
	unsigned long incs = 0, decs = 0;
781
	int cpu;
Linus Torvalds's avatar
Linus Torvalds committed
782

783
	for_each_possible_cpu(cpu)
784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801
		decs += per_cpu_ptr(mod->refptr, cpu)->decs;
	/*
	 * ensure the incs are added up after the decs.
	 * module_put ensures incs are visible before decs with smp_wmb.
	 *
	 * This 2-count scheme avoids the situation where the refcount
	 * for CPU0 is read, then CPU0 increments the module refcount,
	 * then CPU1 drops that refcount, then the refcount for CPU1 is
	 * read. We would record a decrement but not its corresponding
	 * increment so we would see a low count (disaster).
	 *
	 * Rare situation? But module_refcount can be preempted, and we
	 * might be tallying up 4096+ CPUs. So it is not impossible.
	 */
	smp_rmb();
	for_each_possible_cpu(cpu)
		incs += per_cpu_ptr(mod->refptr, cpu)->incs;
	return incs - decs;
Linus Torvalds's avatar
Linus Torvalds committed
802 803 804 805 806 807 808 809
}
EXPORT_SYMBOL(module_refcount);

/* This exists whether we can unload or not */
static void free_module(struct module *mod);

static void wait_for_zero_refcount(struct module *mod)
{
810
	/* Since we might sleep for some time, release the mutex first */
811
	mutex_unlock(&module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
812
	for (;;) {
813
		pr_debug("Looking at refcount...\n");
Linus Torvalds's avatar
Linus Torvalds committed
814 815 816 817 818 819
		set_current_state(TASK_UNINTERRUPTIBLE);
		if (module_refcount(mod) == 0)
			break;
		schedule();
	}
	current->state = TASK_RUNNING;
820
	mutex_lock(&module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
821 822
}

823 824
SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
		unsigned int, flags)
Linus Torvalds's avatar
Linus Torvalds committed
825 826
{
	struct module *mod;
827
	char name[MODULE_NAME_LEN];
Linus Torvalds's avatar
Linus Torvalds committed
828 829
	int ret, forced = 0;

830
	if (!capable(CAP_SYS_MODULE) || modules_disabled)
831 832 833 834 835 836
		return -EPERM;

	if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
		return -EFAULT;
	name[MODULE_NAME_LEN-1] = '\0';

837 838
	if (mutex_lock_interruptible(&module_mutex) != 0)
		return -EINTR;
Linus Torvalds's avatar
Linus Torvalds committed
839 840 841 842 843 844 845

	mod = find_module(name);
	if (!mod) {
		ret = -ENOENT;
		goto out;
	}

846
	if (!list_empty(&mod->source_list)) {
Linus Torvalds's avatar
Linus Torvalds committed
847 848 849 850 851 852 853 854 855
		/* Other modules depend on us: get rid of them first. */
		ret = -EWOULDBLOCK;
		goto out;
	}

	/* Doing init or already dying? */
	if (mod->state != MODULE_STATE_LIVE) {
		/* FIXME: if (force), slam module count and wake up
                   waiter --RR */
856
		pr_debug("%s already dying\n", mod->name);
Linus Torvalds's avatar
Linus Torvalds committed
857 858 859 860 861
		ret = -EBUSY;
		goto out;
	}

	/* If it has an init func, it must have an exit func to unload */
862
	if (mod->init && !mod->exit) {
863
		forced = try_force_unload(flags);
Linus Torvalds's avatar
Linus Torvalds committed
864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882
		if (!forced) {
			/* This module can't be removed */
			ret = -EBUSY;
			goto out;
		}
	}

	/* Set this up before setting mod->state */
	mod->waiter = current;

	/* Stop the machine so refcounts can't move and disable module. */
	ret = try_stop_module(mod, flags, &forced);
	if (ret != 0)
		goto out;

	/* Never wait if forced. */
	if (!forced && module_refcount(mod) != 0)
		wait_for_zero_refcount(mod);

883
	mutex_unlock(&module_mutex);
Lucas De Marchi's avatar
Lucas De Marchi committed
884
	/* Final destruction now no one is using it. */
885
	if (mod->exit != NULL)
Linus Torvalds's avatar
Linus Torvalds committed
886
		mod->exit();
887 888
	blocking_notifier_call_chain(&module_notify_list,
				     MODULE_STATE_GOING, mod);
889
	async_synchronize_full();
890

891
	/* Store the name of the last unloaded module for diagnostic purposes */
892
	strlcpy(last_unloaded_module, mod->name, sizeof(last_unloaded_module));
Linus Torvalds's avatar
Linus Torvalds committed
893

894 895 896
	free_module(mod);
	return 0;
out:
897
	mutex_unlock(&module_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
898 899 900
	return ret;
}

901
static inline void print_unload_info(struct seq_file *m, struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
902 903 904 905
{
	struct module_use *use;
	int printed_something = 0;

906
	seq_printf(m, " %lu ", module_refcount(mod));
Linus Torvalds's avatar
Linus Torvalds committed
907 908 909

	/* Always include a trailing , so userspace can differentiate
           between this and the old multi-field proc format. */
910
	list_for_each_entry(use, &mod->source_list, source_list) {
Linus Torvalds's avatar
Linus Torvalds committed
911
		printed_something = 1;
912
		seq_printf(m, "%s,", use->source->name);
Linus Torvalds's avatar
Linus Torvalds committed
913 914 915 916 917 918 919 920 921 922 923 924 925 926 927
	}

	if (mod->init != NULL && mod->exit == NULL) {
		printed_something = 1;
		seq_printf(m, "[permanent],");
	}

	if (!printed_something)
		seq_printf(m, "-");
}

void __symbol_put(const char *symbol)
{
	struct module *owner;

Rusty Russell's avatar
Rusty Russell committed
928
	preempt_disable();
929
	if (!find_symbol(symbol, &owner, NULL, true, false))
Linus Torvalds's avatar
Linus Torvalds committed
930 931
		BUG();
	module_put(owner);
Rusty Russell's avatar
Rusty Russell committed
932
	preempt_enable();
Linus Torvalds's avatar
Linus Torvalds committed
933 934 935
}
EXPORT_SYMBOL(__symbol_put);

936
/* Note this assumes addr is a function, which it currently always is. */
Linus Torvalds's avatar
Linus Torvalds committed
937 938
void symbol_put_addr(void *addr)
{
939
	struct module *modaddr;
940
	unsigned long a = (unsigned long)dereference_function_descriptor(addr);
Linus Torvalds's avatar
Linus Torvalds committed
941

942
	if (core_kernel_text(a))
943
		return;
Linus Torvalds's avatar
Linus Torvalds committed
944

945 946
	/* module_text_address is safe here: we're supposed to have reference
	 * to module from symbol_get, so it can't go away. */
947
	modaddr = __module_text_address(a);
948
	BUG_ON(!modaddr);
949
	module_put(modaddr);
Linus Torvalds's avatar
Linus Torvalds committed
950 951 952 953
}
EXPORT_SYMBOL_GPL(symbol_put_addr);

static ssize_t show_refcnt(struct module_attribute *mattr,
954
			   struct module_kobject *mk, char *buffer)
Linus Torvalds's avatar
Linus Torvalds committed
955
{
956
	return sprintf(buffer, "%lu\n", module_refcount(mk->mod));
Linus Torvalds's avatar
Linus Torvalds committed
957 958
}

959 960
static struct module_attribute modinfo_refcnt =
	__ATTR(refcnt, 0444, show_refcnt, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
961

962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991
void __module_get(struct module *module)
{
	if (module) {
		preempt_disable();
		__this_cpu_inc(module->refptr->incs);
		trace_module_get(module, _RET_IP_);
		preempt_enable();
	}
}
EXPORT_SYMBOL(__module_get);

bool try_module_get(struct module *module)
{
	bool ret = true;

	if (module) {
		preempt_disable();

		if (likely(module_is_live(module))) {
			__this_cpu_inc(module->refptr->incs);
			trace_module_get(module, _RET_IP_);
		} else
			ret = false;

		preempt_enable();
	}
	return ret;
}
EXPORT_SYMBOL(try_module_get);

Al Viro's avatar
Al Viro committed
992 993 994
void module_put(struct module *module)
{
	if (module) {
995
		preempt_disable();
996 997
		smp_wmb(); /* see comment in module_refcount */
		__this_cpu_inc(module->refptr->decs);
998

999
		trace_module_put(module, _RET_IP_);
Al Viro's avatar
Al Viro committed
1000 1001 1002
		/* Maybe they're waiting for us to drop reference? */
		if (unlikely(!module_is_live(module)))
			wake_up_process(module->waiter);
1003
		preempt_enable();
Al Viro's avatar
Al Viro committed
1004 1005 1006 1007
	}
}
EXPORT_SYMBOL(module_put);

Linus Torvalds's avatar
Linus Torvalds committed
1008
#else /* !CONFIG_MODULE_UNLOAD */
1009
static inline void print_unload_info(struct seq_file *m, struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
1010 1011 1012 1013 1014 1015 1016 1017 1018
{
	/* We don't know the usage count, or what modules are using. */
	seq_printf(m, " - -");
}

static inline void module_unload_free(struct module *mod)
{
}

1019
int ref_module(struct module *a, struct module *b)
Linus Torvalds's avatar
Linus Torvalds committed
1020
{
1021
	return strong_try_module_get(b);
Linus Torvalds's avatar
Linus Torvalds committed
1022
}
1023
EXPORT_SYMBOL_GPL(ref_module);
Linus Torvalds's avatar
Linus Torvalds committed
1024

1025
static inline int module_unload_init(struct module *mod)
Linus Torvalds's avatar
Linus Torvalds committed
1026
{
1027
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
1028 1029 1030
}
#endif /* CONFIG_MODULE_UNLOAD */

1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050
static size_t module_flags_taint(struct module *mod, char *buf)
{
	size_t l = 0;

	if (mod->taints & (1 << TAINT_PROPRIETARY_MODULE))
		buf[l++] = 'P';
	if (mod->taints & (1 << TAINT_OOT_MODULE))
		buf[l++] = 'O';
	if (mod->taints & (1 << TAINT_FORCED_MODULE))
		buf[l++] = 'F';
	if (mod->taints & (1 << TAINT_CRAP))
		buf[l++] = 'C';
	/*
	 * TAINT_FORCED_RMMOD: could be added.
	 * TAINT_UNSAFE_SMP, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
	 * apply to modules.
	 */
	return l;
}

1051
static ssize_t show_initstate(struct module_attribute *mattr,
1052
			      struct module_kobject *mk, char *buffer)
1053 1054 1055
{
	const char *state = "unknown";

1056
	switch (mk->mod->state) {
1057 1058 1059 1060 1061 1062 1063 1064 1065
	case MODULE_STATE_LIVE:
		state = "live";
		break;
	case MODULE_STATE_COMING:
		state = "coming";
		break;
	case MODULE_STATE_GOING:
		state = "going";
		break;
1066 1067
	default:
		BUG();
1068 1069 1070 1071
	}
	return sprintf(buffer, "%s\n", state);
}

1072 1073
static struct module_attribute modinfo_initstate =
	__ATTR(initstate, 0444, show_initstate, NULL);
1074

1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085
static ssize_t store_uevent(struct module_attribute *mattr,
			    struct module_kobject *mk,
			    const char *buffer, size_t count)
{
	enum kobject_action action;

	if (kobject_action_type(buffer, count, &action) == 0)
		kobject_uevent(&mk->kobj, action);
	return count;
}

1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118
struct module_attribute module_uevent =
	__ATTR(uevent, 0200, NULL, store_uevent);

static ssize_t show_coresize(struct module_attribute *mattr,
			     struct module_kobject *mk, char *buffer)
{
	return sprintf(buffer, "%u\n", mk->mod->core_size);
}

static struct module_attribute modinfo_coresize =
	__ATTR(coresize, 0444, show_coresize, NULL);

static ssize_t show_initsize(struct module_attribute *mattr,
			     struct module_kobject *mk, char *buffer)
{
	return sprintf(buffer, "%u\n", mk->mod->init_size);
}

static struct module_attribute modinfo_initsize =
	__ATTR(initsize, 0444, show_initsize, NULL);

static ssize_t show_taint(struct module_attribute *mattr,
			  struct module_kobject *mk, char *buffer)
{
	size_t l;

	l = module_flags_taint(mk->mod, buffer);
	buffer[l++] = '\n';
	return l;
}

static struct module_attribute modinfo_taint =
	__ATTR(taint, 0444, show_taint, NULL);
1119

1120
static struct module_attribute *modinfo_attrs[] = {
1121
	&module_uevent,
1122 1123
	&modinfo_version,
	&modinfo_srcversion,
1124 1125 1126 1127
	&modinfo_initstate,
	&modinfo_coresize,
	&modinfo_initsize,
	&modinfo_taint,
1128
#ifdef CONFIG_MODULE_UNLOAD
1129
	&modinfo_refcnt,
1130 1131 1132 1133
#endif
	NULL,
};

Linus Torvalds's avatar
Linus Torvalds committed
1134 1135
static const char vermagic[] = VERMAGIC_STRING;

1136
static int try_to_force_load(struct module *mod, const char *reason)
1137 1138
{
#ifdef CONFIG_MODULE_FORCE_LOAD
Andi Kleen's avatar
Andi Kleen committed
1139
	if (!test_taint(TAINT_FORCED_MODULE))
1140 1141
		printk(KERN_WARNING "%s: %s: kernel tainted.\n",
		       mod->name, reason);
1142
	add_taint_module(mod, TAINT_FORCED_MODULE, LOCKDEP_NOW_UNRELIABLE);
1143 1144 1145 1146 1147 1148
	return 0;
#else
	return -ENOEXEC;
#endif
}

Linus Torvalds's avatar
Linus Torvalds committed
1149
#ifdef CONFIG_MODVERSIONS
1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160
/* If the arch applies (non-zero) relocations to kernel kcrctab, unapply it. */
static unsigned long maybe_relocated(unsigned long crc,
				     const struct module *crc_owner)
{
#ifdef ARCH_RELOCATES_KCRCTAB
	if (crc_owner == NULL)
		return crc - (unsigned long)reloc_start;
#endif
	return crc;
}

Linus Torvalds's avatar
Linus Torvalds committed
1161 1162 1163 1164
static int check_version(Elf_Shdr *sechdrs,
			 unsigned int versindex,
			 const char *symname,
			 struct module *mod, 
1165 1166
			 const unsigned long *crc,
			 const struct module *crc_owner)
Linus Torvalds's avatar
Linus Torvalds committed
1167 1168 1169 1170 1171 1172 1173 1174
{
	unsigned int i, num_versions;
	struct modversion_info *versions;

	/* Exporting module didn't supply crcs?  OK, we're already tainted. */
	if (!crc)
		return 1;

1175 1176 1177 1178
	/* No versions at all?  modprobe --force does this. */
	if (versindex == 0)
		return try_to_force_load(mod, symname) == 0;

Linus Torvalds's avatar
Linus Torvalds committed
1179 1180 1181 1182 1183 1184 1185 1186
	versions = (void *) sechdrs[versindex].sh_addr;
	num_versions = sechdrs[versindex].sh_size
		/ sizeof(struct modversion_info);

	for (i = 0; i < num_versions; i++) {
		if (strcmp(versions[i].name, symname) != 0)
			continue;

1187
		if (versions[i].crc == maybe_relocated(*crc, crc_owner))
Linus Torvalds's avatar
Linus Torvalds committed
1188
			return 1;
1189
		pr_debug("Found checksum %lX vs module %lX\n",
1190
		       maybe_relocated(*crc, crc_owner), versions[i].crc);
1191
		goto bad_version;
Linus Torvalds's avatar
Linus Torvalds committed
1192
	}
1193

1194 1195 1196
	printk(KERN_WARNING "%s: no symbol version for %s\n",
	       mod->name, symname);
	return 0;
1197 1198 1199 1200 1201

bad_version:
	printk("%s: disagrees about version of symbol %s\n",
	       mod->name, symname);
	return 0;
Linus Torvalds's avatar
Linus Torvalds committed
1202 1203 1204 1205 1206 1207 1208 1209
}

static inline int check_modstruct_version(Elf_Shdr *sechdrs,
					  unsigned int versindex,
					  struct module *mod)
{
	const unsigned long *crc;

1210 1211
	/* Since this should be found in kernel (which can't be removed),
	 * no locking is necessary. */
1212
	if (!find_symbol(VMLINUX_SYMBOL_STR(module_layout), NULL,
1213
			 &crc, true, false))
Linus Torvalds's avatar
Linus Torvalds committed
1214
		BUG();
1215 1216
	return check_version(sechdrs, versindex,
			     VMLINUX_SYMBOL_STR(module_layout), mod, crc,
1217
			     NULL);