summaryrefslogtreecommitdiff
path: root/kernel/module/internal.h
blob: dc7b0160c4807e13a6ab672ae15fc463c4f6c6d8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
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
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
/* SPDX-License-Identifier: GPL-2.0-or-later */
/* Module internals
 *
 * Copyright (C) 2012 Red Hat, Inc. All Rights Reserved.
 * Written by David Howells (dhowells@redhat.com)
 * Copyright (C) 2023 Luis Chamberlain <mcgrof@kernel.org>
 */

#include <linux/elf.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/mm.h>

#ifndef ARCH_SHF_SMALL
#define ARCH_SHF_SMALL 0
#endif

/*
 * Use highest 4 bits of sh_entsize to store the mod_mem_type of this
 * section. This leaves 28 bits for offset on 32-bit systems, which is
 * about 256 MiB (WARN_ON_ONCE if we exceed that).
 */

#define SH_ENTSIZE_TYPE_BITS	4
#define SH_ENTSIZE_TYPE_SHIFT	(BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)
#define SH_ENTSIZE_TYPE_MASK	((1UL << SH_ENTSIZE_TYPE_BITS) - 1)
#define SH_ENTSIZE_OFFSET_MASK	((1UL << (BITS_PER_LONG - SH_ENTSIZE_TYPE_BITS)) - 1)

/* Maximum number of characters written by module_flags() */
#define MODULE_FLAGS_BUF_SIZE (TAINT_FLAGS_COUNT + 4)

extern struct mutex module_mutex;
extern struct list_head modules;

extern struct module_attribute *modinfo_attrs[];
extern size_t modinfo_attrs_count;

/* 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[];
extern const s32 __start___kcrctab[];
extern const s32 __start___kcrctab_gpl[];

struct load_info {
	const char *name;
	/* pointer to module in temporary copy, freed at end of load_module() */
	struct module *mod;
	Elf_Ehdr *hdr;
	unsigned long len;
	Elf_Shdr *sechdrs;
	char *secstrings, *strtab;
	unsigned long symoffs, stroffs, init_typeoffs, core_typeoffs;
	bool sig_ok;
#ifdef CONFIG_KALLSYMS
	unsigned long mod_kallsyms_init_off;
#endif
#ifdef CONFIG_MODULE_DECOMPRESS
#ifdef CONFIG_MODULE_STATS
	unsigned long compressed_len;
#endif
	struct page **pages;
	unsigned int max_pages;
	unsigned int used_pages;
#endif
	struct {
		unsigned int sym, str, mod, vers, info, pcpu;
	} index;
};

enum mod_license {
	NOT_GPL_ONLY,
	GPL_ONLY,
};

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

	/* Output */
	struct module *owner;
	const s32 *crc;
	const struct kernel_symbol *sym;
	enum mod_license license;
};

int mod_verify_sig(const void *mod, struct load_info *info);
int try_to_force_load(struct module *mod, const char *reason);
bool find_symbol(struct find_symbol_arg *fsa);
struct module *find_module_all(const char *name, size_t len, bool even_unformed);
int cmp_name(const void *name, const void *sym);
long module_get_offset_and_type(struct module *mod, enum mod_mem_type type,
				Elf_Shdr *sechdr, unsigned int section);
char *module_flags(struct module *mod, char *buf, bool show_state);
size_t module_flags_taint(unsigned long taints, char *buf);

char *module_next_tag_pair(char *string, unsigned long *secsize);

#define for_each_modinfo_entry(entry, info, name) \
	for (entry = get_modinfo(info, name); entry; entry = get_next_modinfo(info, name, entry))

static inline void module_assert_mutex_or_preempt(void)
{
#ifdef CONFIG_LOCKDEP
	if (unlikely(!debug_locks))
		return;

	WARN_ON_ONCE(!rcu_read_lock_sched_held() &&
		     !lockdep_is_held(&module_mutex));
#endif
}

static inline unsigned long kernel_symbol_value(const struct kernel_symbol *sym)
{
#ifdef CONFIG_HAVE_ARCH_PREL32_RELOCATIONS
	return (unsigned long)offset_to_ptr(&sym->value_offset);
#else
	return sym->value;
#endif
}

#ifdef CONFIG_LIVEPATCH
int copy_module_elf(struct module *mod, struct load_info *info);
void free_module_elf(struct module *mod);
#else /* !CONFIG_LIVEPATCH */
static inline int copy_module_elf(struct module *mod, struct load_info *info)
{
	return 0;
}

static inline void free_module_elf(struct module *mod) { }
#endif /* CONFIG_LIVEPATCH */

static inline bool set_livepatch_module(struct module *mod)
{
#ifdef CONFIG_LIVEPATCH
	mod->klp = true;
	return true;
#else
	return false;
#endif
}

/**
 * enum fail_dup_mod_reason - state at which a duplicate module was detected
 *
 * @FAIL_DUP_MOD_BECOMING: the module is read properly, passes all checks but
 * 	we've determined that another module with the same name is already loaded
 * 	or being processed on our &modules list. This happens on early_mod_check()
 * 	right before layout_and_allocate(). The kernel would have already
 * 	vmalloc()'d space for the entire module through finit_module(). If
 * 	decompression was used two vmap() spaces were used. These failures can
 * 	happen when userspace has not seen the module present on the kernel and
 * 	tries to load the module multiple times at same time.
 * @FAIL_DUP_MOD_LOAD: the module has been read properly, passes all validation
 *	checks and the kernel determines that the module was unique and because
 *	of this allocated yet another private kernel copy of the module space in
 *	layout_and_allocate() but after this determined in add_unformed_module()
 *	that another module with the same name is already loaded or being processed.
 *	These failures should be mitigated as much as possible and are indicative
 *	of really fast races in loading modules. Without module decompression
 *	they waste twice as much vmap space. With module decompression three
 *	times the module's size vmap space is wasted.
 */
enum fail_dup_mod_reason {
	FAIL_DUP_MOD_BECOMING = 0,
	FAIL_DUP_MOD_LOAD,
};

#ifdef CONFIG_MODULE_DEBUGFS
extern struct dentry *mod_debugfs_root;
#endif

#ifdef CONFIG_MODULE_STATS

#define mod_stat_add_long(count, var) atomic_long_add(count, var)
#define mod_stat_inc(name) atomic_inc(name)

extern atomic_long_t total_mod_size;
extern atomic_long_t total_text_size;
extern atomic_long_t invalid_kread_bytes;
extern atomic_long_t invalid_decompress_bytes;

extern atomic_t modcount;
extern atomic_t failed_kreads;
extern atomic_t failed_decompress;
struct mod_fail_load {
	struct list_head list;
	char name[MODULE_NAME_LEN];
	atomic_long_t count;
	unsigned long dup_fail_mask;
};

int try_add_failed_module(const char *name, enum fail_dup_mod_reason reason);
void mod_stat_bump_invalid(struct load_info *info, int flags);
void mod_stat_bump_becoming(struct load_info *info, int flags);

#else

#define mod_stat_add_long(name, var)
#define mod_stat_inc(name)

static inline int try_add_failed_module(const char *name,
					enum fail_dup_mod_reason reason)
{
	return 0;
}

static inline void mod_stat_bump_invalid(struct load_info *info, int flags)
{
}

static inline void mod_stat_bump_becoming(struct load_info *info, int flags)
{
}

#endif /* CONFIG_MODULE_STATS */

#ifdef CONFIG_MODULE_DEBUG_AUTOLOAD_DUPS
bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret);
void kmod_dup_request_announce(char *module_name, int ret);
#else
static inline bool kmod_dup_request_exists_wait(char *module_name, bool wait, int *dup_ret)
{
	return false;
}

static inline void kmod_dup_request_announce(char *module_name, int ret)
{
}
#endif

#ifdef CONFIG_MODULE_UNLOAD_TAINT_TRACKING
struct mod_unload_taint {
	struct list_head list;
	char name[MODULE_NAME_LEN];
	unsigned long taints;
	u64 count;
};

int try_add_tainted_module(struct module *mod);
void print_unloaded_tainted_modules(void);
#else /* !CONFIG_MODULE_UNLOAD_TAINT_TRACKING */
static inline int try_add_tainted_module(struct module *mod)
{
	return 0;
}

static inline void print_unloaded_tainted_modules(void)
{
}
#endif /* CONFIG_MODULE_UNLOAD_TAINT_TRACKING */

#ifdef CONFIG_MODULE_DECOMPRESS
int module_decompress(struct load_info *info, const void *buf, size_t size);
void module_decompress_cleanup(struct load_info *info);
#else
static inline int module_decompress(struct load_info *info,
				    const void *buf, size_t size)
{
	return -EOPNOTSUPP;
}

static inline void module_decompress_cleanup(struct load_info *info)
{
}
#endif

struct mod_tree_root {
#ifdef CONFIG_MODULES_TREE_LOOKUP
	struct latch_tree_root root;
#endif
	unsigned long addr_min;
	unsigned long addr_max;
#ifdef CONFIG_ARCH_WANTS_MODULES_DATA_IN_VMALLOC
	unsigned long data_addr_min;
	unsigned long data_addr_max;
#endif
};

extern struct mod_tree_root mod_tree;

#ifdef CONFIG_MODULES_TREE_LOOKUP
void mod_tree_insert(struct module *mod);
void mod_tree_remove_init(struct module *mod);
void mod_tree_remove(struct module *mod);
struct module *mod_find(unsigned long addr, struct mod_tree_root *tree);
#else /* !CONFIG_MODULES_TREE_LOOKUP */

static inline void mod_tree_insert(struct module *mod) { }
static inline void mod_tree_remove_init(struct module *mod) { }
static inline void mod_tree_remove(struct module *mod) { }
static inline struct module *mod_find(unsigned long addr, struct mod_tree_root *tree)
{
	struct module *mod;

	list_for_each_entry_rcu(mod, &modules, list,
				lockdep_is_held(&module_mutex)) {
		if (within_module(addr, mod))
			return mod;
	}

	return NULL;
}
#endif /* CONFIG_MODULES_TREE_LOOKUP */

void module_enable_ro(const struct module *mod, bool after_init);
void module_enable_nx(const struct module *mod);
void module_enable_x(const struct module *mod);
int module_enforce_rwx_sections(Elf_Ehdr *hdr, Elf_Shdr *sechdrs,
				char *secstrings, struct module *mod);

#ifdef CONFIG_MODULE_SIG
int module_sig_check(struct load_info *info, int flags);
#else /* !CONFIG_MODULE_SIG */
static inline int module_sig_check(struct load_info *info, int flags)
{
	return 0;
}
#endif /* !CONFIG_MODULE_SIG */

#ifdef CONFIG_DEBUG_KMEMLEAK
void kmemleak_load_module(const struct module *mod, const struct load_info *info);
#else /* !CONFIG_DEBUG_KMEMLEAK */
static inline void kmemleak_load_module(const struct module *mod,
					const struct load_info *info) { }
#endif /* CONFIG_DEBUG_KMEMLEAK */

#ifdef CONFIG_KALLSYMS
void init_build_id(struct module *mod, const struct load_info *info);
void layout_symtab(struct module *mod, struct load_info *info);
void add_kallsyms(struct module *mod, const struct load_info *info);

static inline bool sect_empty(const Elf_Shdr *sect)
{
	return !(sect->sh_flags & SHF_ALLOC) || sect->sh_size == 0;
}
#else /* !CONFIG_KALLSYMS */
static inline void init_build_id(struct module *mod, const struct load_info *info) { }
static inline void layout_symtab(struct module *mod, struct load_info *info) { }
static inline void add_kallsyms(struct module *mod, const struct load_info *info) { }
#endif /* CONFIG_KALLSYMS */

#ifdef CONFIG_SYSFS
int mod_sysfs_setup(struct module *mod, const struct load_info *info,
		    struct kernel_param *kparam, unsigned int num_params);
void mod_sysfs_teardown(struct module *mod);
void init_param_lock(struct module *mod);
#else /* !CONFIG_SYSFS */
static inline int mod_sysfs_setup(struct module *mod,
			   	  const struct load_info *info,
			   	  struct kernel_param *kparam,
			   	  unsigned int num_params)
{
	return 0;
}

static inline void mod_sysfs_teardown(struct module *mod) { }
static inline void init_param_lock(struct module *mod) { }
#endif /* CONFIG_SYSFS */

#ifdef CONFIG_MODVERSIONS
int check_version(const struct load_info *info,
		  const char *symname, struct module *mod, const s32 *crc);
void module_layout(struct module *mod, struct modversion_info *ver, struct kernel_param *kp,
		   struct kernel_symbol *ks, struct tracepoint * const *tp);
int check_modstruct_version(const struct load_info *info, struct module *mod);
int same_magic(const char *amagic, const char *bmagic, bool has_crcs);
#else /* !CONFIG_MODVERSIONS */
static inline int check_version(const struct load_info *info,
				const char *symname,
				struct module *mod,
				const s32 *crc)
{
	return 1;
}

static inline int check_modstruct_version(const struct load_info *info,
					  struct module *mod)
{
	return 1;
}

static inline int same_magic(const char *amagic, const char *bmagic, bool has_crcs)
{
	return strcmp(amagic, bmagic) == 0;
}
#endif /* CONFIG_MODVERSIONS */