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1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Kernel module help for x86.
3 Copyright (C) 2001 Rusty Russell.
4
5*/
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/moduleloader.h>
10#include <linux/elf.h>
11#include <linux/vmalloc.h>
12#include <linux/fs.h>
13#include <linux/string.h>
14#include <linux/kernel.h>
15#include <linux/kasan.h>
16#include <linux/bug.h>
17#include <linux/mm.h>
18#include <linux/gfp.h>
19#include <linux/jump_label.h>
20#include <linux/random.h>
21#include <linux/memory.h>
22
23#include <asm/text-patching.h>
24#include <asm/page.h>
25#include <asm/setup.h>
26#include <asm/unwind.h>
27
28#if 0
29#define DEBUGP(fmt, ...) \
30 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
31#else
32#define DEBUGP(fmt, ...) \
33do { \
34 if (0) \
35 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
36} while (0)
37#endif
38
39#ifdef CONFIG_RANDOMIZE_BASE
40static unsigned long module_load_offset;
41
42/* Mutex protects the module_load_offset. */
43static DEFINE_MUTEX(module_kaslr_mutex);
44
45static unsigned long int get_module_load_offset(void)
46{
47 if (kaslr_enabled()) {
48 mutex_lock(&module_kaslr_mutex);
49 /*
50 * Calculate the module_load_offset the first time this
51 * code is called. Once calculated it stays the same until
52 * reboot.
53 */
54 if (module_load_offset == 0)
55 module_load_offset =
56 (get_random_int() % 1024 + 1) * PAGE_SIZE;
57 mutex_unlock(&module_kaslr_mutex);
58 }
59 return module_load_offset;
60}
61#else
62static unsigned long int get_module_load_offset(void)
63{
64 return 0;
65}
66#endif
67
68void *module_alloc(unsigned long size)
69{
70 void *p;
71
72 if (PAGE_ALIGN(size) > MODULES_LEN)
73 return NULL;
74
75 p = __vmalloc_node_range(size, MODULE_ALIGN,
76 MODULES_VADDR + get_module_load_offset(),
77 MODULES_END, GFP_KERNEL,
78 PAGE_KERNEL, 0, NUMA_NO_NODE,
79 __builtin_return_address(0));
80 if (p && (kasan_module_alloc(p, size) < 0)) {
81 vfree(p);
82 return NULL;
83 }
84
85 return p;
86}
87
88#ifdef CONFIG_X86_32
89int apply_relocate(Elf32_Shdr *sechdrs,
90 const char *strtab,
91 unsigned int symindex,
92 unsigned int relsec,
93 struct module *me)
94{
95 unsigned int i;
96 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
97 Elf32_Sym *sym;
98 uint32_t *location;
99
100 DEBUGP("Applying relocate section %u to %u\n",
101 relsec, sechdrs[relsec].sh_info);
102 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
103 /* This is where to make the change */
104 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
105 + rel[i].r_offset;
106 /* This is the symbol it is referring to. Note that all
107 undefined symbols have been resolved. */
108 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
109 + ELF32_R_SYM(rel[i].r_info);
110
111 switch (ELF32_R_TYPE(rel[i].r_info)) {
112 case R_386_32:
113 /* We add the value into the location given */
114 *location += sym->st_value;
115 break;
116 case R_386_PC32:
117 case R_386_PLT32:
118 /* Add the value, subtract its position */
119 *location += sym->st_value - (uint32_t)location;
120 break;
121 default:
122 pr_err("%s: Unknown relocation: %u\n",
123 me->name, ELF32_R_TYPE(rel[i].r_info));
124 return -ENOEXEC;
125 }
126 }
127 return 0;
128}
129#else /*X86_64*/
130static int __apply_relocate_add(Elf64_Shdr *sechdrs,
131 const char *strtab,
132 unsigned int symindex,
133 unsigned int relsec,
134 struct module *me,
135 void *(*write)(void *dest, const void *src, size_t len))
136{
137 unsigned int i;
138 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
139 Elf64_Sym *sym;
140 void *loc;
141 u64 val;
142
143 DEBUGP("Applying relocate section %u to %u\n",
144 relsec, sechdrs[relsec].sh_info);
145 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
146 /* This is where to make the change */
147 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
148 + rel[i].r_offset;
149
150 /* This is the symbol it is referring to. Note that all
151 undefined symbols have been resolved. */
152 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
153 + ELF64_R_SYM(rel[i].r_info);
154
155 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
156 (int)ELF64_R_TYPE(rel[i].r_info),
157 sym->st_value, rel[i].r_addend, (u64)loc);
158
159 val = sym->st_value + rel[i].r_addend;
160
161 switch (ELF64_R_TYPE(rel[i].r_info)) {
162 case R_X86_64_NONE:
163 break;
164 case R_X86_64_64:
165 if (*(u64 *)loc != 0)
166 goto invalid_relocation;
167 write(loc, &val, 8);
168 break;
169 case R_X86_64_32:
170 if (*(u32 *)loc != 0)
171 goto invalid_relocation;
172 write(loc, &val, 4);
173 if (val != *(u32 *)loc)
174 goto overflow;
175 break;
176 case R_X86_64_32S:
177 if (*(s32 *)loc != 0)
178 goto invalid_relocation;
179 write(loc, &val, 4);
180 if ((s64)val != *(s32 *)loc)
181 goto overflow;
182 break;
183 case R_X86_64_PC32:
184 case R_X86_64_PLT32:
185 if (*(u32 *)loc != 0)
186 goto invalid_relocation;
187 val -= (u64)loc;
188 write(loc, &val, 4);
189#if 0
190 if ((s64)val != *(s32 *)loc)
191 goto overflow;
192#endif
193 break;
194 case R_X86_64_PC64:
195 if (*(u64 *)loc != 0)
196 goto invalid_relocation;
197 val -= (u64)loc;
198 write(loc, &val, 8);
199 break;
200 default:
201 pr_err("%s: Unknown rela relocation: %llu\n",
202 me->name, ELF64_R_TYPE(rel[i].r_info));
203 return -ENOEXEC;
204 }
205 }
206 return 0;
207
208invalid_relocation:
209 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
210 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
211 return -ENOEXEC;
212
213overflow:
214 pr_err("overflow in relocation type %d val %Lx\n",
215 (int)ELF64_R_TYPE(rel[i].r_info), val);
216 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
217 me->name);
218 return -ENOEXEC;
219}
220
221int apply_relocate_add(Elf64_Shdr *sechdrs,
222 const char *strtab,
223 unsigned int symindex,
224 unsigned int relsec,
225 struct module *me)
226{
227 int ret;
228 bool early = me->state == MODULE_STATE_UNFORMED;
229 void *(*write)(void *, const void *, size_t) = memcpy;
230
231 if (!early) {
232 write = text_poke;
233 mutex_lock(&text_mutex);
234 }
235
236 ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
237 write);
238
239 if (!early) {
240 text_poke_sync();
241 mutex_unlock(&text_mutex);
242 }
243
244 return ret;
245}
246
247#endif
248
249int module_finalize(const Elf_Ehdr *hdr,
250 const Elf_Shdr *sechdrs,
251 struct module *me)
252{
253 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
254 *para = NULL, *orc = NULL, *orc_ip = NULL;
255 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
256
257 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
258 if (!strcmp(".text", secstrings + s->sh_name))
259 text = s;
260 if (!strcmp(".altinstructions", secstrings + s->sh_name))
261 alt = s;
262 if (!strcmp(".smp_locks", secstrings + s->sh_name))
263 locks = s;
264 if (!strcmp(".parainstructions", secstrings + s->sh_name))
265 para = s;
266 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
267 orc = s;
268 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
269 orc_ip = s;
270 }
271
272 if (alt) {
273 /* patch .altinstructions */
274 void *aseg = (void *)alt->sh_addr;
275 apply_alternatives(aseg, aseg + alt->sh_size);
276 }
277 if (locks && text) {
278 void *lseg = (void *)locks->sh_addr;
279 void *tseg = (void *)text->sh_addr;
280 alternatives_smp_module_add(me, me->name,
281 lseg, lseg + locks->sh_size,
282 tseg, tseg + text->sh_size);
283 }
284
285 if (para) {
286 void *pseg = (void *)para->sh_addr;
287 apply_paravirt(pseg, pseg + para->sh_size);
288 }
289
290 /* make jump label nops */
291 jump_label_apply_nops(me);
292
293 if (orc && orc_ip)
294 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
295 (void *)orc->sh_addr, orc->sh_size);
296
297 return 0;
298}
299
300void module_arch_cleanup(struct module *mod)
301{
302 alternatives_smp_module_del(mod);
303}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* Kernel module help for x86.
3 Copyright (C) 2001 Rusty Russell.
4
5*/
6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/moduleloader.h>
10#include <linux/elf.h>
11#include <linux/vmalloc.h>
12#include <linux/fs.h>
13#include <linux/string.h>
14#include <linux/kernel.h>
15#include <linux/kasan.h>
16#include <linux/bug.h>
17#include <linux/mm.h>
18#include <linux/gfp.h>
19#include <linux/jump_label.h>
20#include <linux/random.h>
21#include <linux/memory.h>
22
23#include <asm/text-patching.h>
24#include <asm/page.h>
25#include <asm/setup.h>
26#include <asm/unwind.h>
27
28#if 0
29#define DEBUGP(fmt, ...) \
30 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
31#else
32#define DEBUGP(fmt, ...) \
33do { \
34 if (0) \
35 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
36} while (0)
37#endif
38
39#ifdef CONFIG_RANDOMIZE_BASE
40static unsigned long module_load_offset;
41
42/* Mutex protects the module_load_offset. */
43static DEFINE_MUTEX(module_kaslr_mutex);
44
45static unsigned long int get_module_load_offset(void)
46{
47 if (kaslr_enabled()) {
48 mutex_lock(&module_kaslr_mutex);
49 /*
50 * Calculate the module_load_offset the first time this
51 * code is called. Once calculated it stays the same until
52 * reboot.
53 */
54 if (module_load_offset == 0)
55 module_load_offset =
56 get_random_u32_inclusive(1, 1024) * PAGE_SIZE;
57 mutex_unlock(&module_kaslr_mutex);
58 }
59 return module_load_offset;
60}
61#else
62static unsigned long int get_module_load_offset(void)
63{
64 return 0;
65}
66#endif
67
68void *module_alloc(unsigned long size)
69{
70 gfp_t gfp_mask = GFP_KERNEL;
71 void *p;
72
73 if (PAGE_ALIGN(size) > MODULES_LEN)
74 return NULL;
75
76 p = __vmalloc_node_range(size, MODULE_ALIGN,
77 MODULES_VADDR + get_module_load_offset(),
78 MODULES_END, gfp_mask, PAGE_KERNEL,
79 VM_FLUSH_RESET_PERMS | VM_DEFER_KMEMLEAK,
80 NUMA_NO_NODE, __builtin_return_address(0));
81
82 if (p && (kasan_alloc_module_shadow(p, size, gfp_mask) < 0)) {
83 vfree(p);
84 return NULL;
85 }
86
87 return p;
88}
89
90#ifdef CONFIG_X86_32
91int apply_relocate(Elf32_Shdr *sechdrs,
92 const char *strtab,
93 unsigned int symindex,
94 unsigned int relsec,
95 struct module *me)
96{
97 unsigned int i;
98 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
99 Elf32_Sym *sym;
100 uint32_t *location;
101
102 DEBUGP("Applying relocate section %u to %u\n",
103 relsec, sechdrs[relsec].sh_info);
104 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
105 /* This is where to make the change */
106 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
107 + rel[i].r_offset;
108 /* This is the symbol it is referring to. Note that all
109 undefined symbols have been resolved. */
110 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
111 + ELF32_R_SYM(rel[i].r_info);
112
113 switch (ELF32_R_TYPE(rel[i].r_info)) {
114 case R_386_32:
115 /* We add the value into the location given */
116 *location += sym->st_value;
117 break;
118 case R_386_PC32:
119 case R_386_PLT32:
120 /* Add the value, subtract its position */
121 *location += sym->st_value - (uint32_t)location;
122 break;
123 default:
124 pr_err("%s: Unknown relocation: %u\n",
125 me->name, ELF32_R_TYPE(rel[i].r_info));
126 return -ENOEXEC;
127 }
128 }
129 return 0;
130}
131#else /*X86_64*/
132static int __write_relocate_add(Elf64_Shdr *sechdrs,
133 const char *strtab,
134 unsigned int symindex,
135 unsigned int relsec,
136 struct module *me,
137 void *(*write)(void *dest, const void *src, size_t len),
138 bool apply)
139{
140 unsigned int i;
141 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
142 Elf64_Sym *sym;
143 void *loc;
144 u64 val;
145 u64 zero = 0ULL;
146
147 DEBUGP("%s relocate section %u to %u\n",
148 apply ? "Applying" : "Clearing",
149 relsec, sechdrs[relsec].sh_info);
150 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
151 size_t size;
152
153 /* This is where to make the change */
154 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
155 + rel[i].r_offset;
156
157 /* This is the symbol it is referring to. Note that all
158 undefined symbols have been resolved. */
159 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
160 + ELF64_R_SYM(rel[i].r_info);
161
162 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
163 (int)ELF64_R_TYPE(rel[i].r_info),
164 sym->st_value, rel[i].r_addend, (u64)loc);
165
166 val = sym->st_value + rel[i].r_addend;
167
168 switch (ELF64_R_TYPE(rel[i].r_info)) {
169 case R_X86_64_NONE:
170 continue; /* nothing to write */
171 case R_X86_64_64:
172 size = 8;
173 break;
174 case R_X86_64_32:
175 if (val != *(u32 *)&val)
176 goto overflow;
177 size = 4;
178 break;
179 case R_X86_64_32S:
180 if ((s64)val != *(s32 *)&val)
181 goto overflow;
182 size = 4;
183 break;
184 case R_X86_64_PC32:
185 case R_X86_64_PLT32:
186 val -= (u64)loc;
187 size = 4;
188 break;
189 case R_X86_64_PC64:
190 val -= (u64)loc;
191 size = 8;
192 break;
193 default:
194 pr_err("%s: Unknown rela relocation: %llu\n",
195 me->name, ELF64_R_TYPE(rel[i].r_info));
196 return -ENOEXEC;
197 }
198
199 if (apply) {
200 if (memcmp(loc, &zero, size)) {
201 pr_err("x86/modules: Invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
202 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
203 return -ENOEXEC;
204 }
205 write(loc, &val, size);
206 } else {
207 if (memcmp(loc, &val, size)) {
208 pr_warn("x86/modules: Invalid relocation target, existing value does not match expected value for type %d, loc %p, val %Lx\n",
209 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
210 return -ENOEXEC;
211 }
212 write(loc, &zero, size);
213 }
214 }
215 return 0;
216
217overflow:
218 pr_err("overflow in relocation type %d val %Lx\n",
219 (int)ELF64_R_TYPE(rel[i].r_info), val);
220 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
221 me->name);
222 return -ENOEXEC;
223}
224
225static int write_relocate_add(Elf64_Shdr *sechdrs,
226 const char *strtab,
227 unsigned int symindex,
228 unsigned int relsec,
229 struct module *me,
230 bool apply)
231{
232 int ret;
233 bool early = me->state == MODULE_STATE_UNFORMED;
234 void *(*write)(void *, const void *, size_t) = memcpy;
235
236 if (!early) {
237 write = text_poke;
238 mutex_lock(&text_mutex);
239 }
240
241 ret = __write_relocate_add(sechdrs, strtab, symindex, relsec, me,
242 write, apply);
243
244 if (!early) {
245 text_poke_sync();
246 mutex_unlock(&text_mutex);
247 }
248
249 return ret;
250}
251
252int apply_relocate_add(Elf64_Shdr *sechdrs,
253 const char *strtab,
254 unsigned int symindex,
255 unsigned int relsec,
256 struct module *me)
257{
258 return write_relocate_add(sechdrs, strtab, symindex, relsec, me, true);
259}
260
261#ifdef CONFIG_LIVEPATCH
262void clear_relocate_add(Elf64_Shdr *sechdrs,
263 const char *strtab,
264 unsigned int symindex,
265 unsigned int relsec,
266 struct module *me)
267{
268 write_relocate_add(sechdrs, strtab, symindex, relsec, me, false);
269}
270#endif
271
272#endif
273
274int module_finalize(const Elf_Ehdr *hdr,
275 const Elf_Shdr *sechdrs,
276 struct module *me)
277{
278 const Elf_Shdr *s, *alt = NULL, *locks = NULL,
279 *orc = NULL, *orc_ip = NULL,
280 *retpolines = NULL, *returns = NULL, *ibt_endbr = NULL,
281 *calls = NULL, *cfi = NULL;
282 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
283
284 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
285 if (!strcmp(".altinstructions", secstrings + s->sh_name))
286 alt = s;
287 if (!strcmp(".smp_locks", secstrings + s->sh_name))
288 locks = s;
289 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
290 orc = s;
291 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
292 orc_ip = s;
293 if (!strcmp(".retpoline_sites", secstrings + s->sh_name))
294 retpolines = s;
295 if (!strcmp(".return_sites", secstrings + s->sh_name))
296 returns = s;
297 if (!strcmp(".call_sites", secstrings + s->sh_name))
298 calls = s;
299 if (!strcmp(".cfi_sites", secstrings + s->sh_name))
300 cfi = s;
301 if (!strcmp(".ibt_endbr_seal", secstrings + s->sh_name))
302 ibt_endbr = s;
303 }
304
305 if (retpolines || cfi) {
306 void *rseg = NULL, *cseg = NULL;
307 unsigned int rsize = 0, csize = 0;
308
309 if (retpolines) {
310 rseg = (void *)retpolines->sh_addr;
311 rsize = retpolines->sh_size;
312 }
313
314 if (cfi) {
315 cseg = (void *)cfi->sh_addr;
316 csize = cfi->sh_size;
317 }
318
319 apply_fineibt(rseg, rseg + rsize, cseg, cseg + csize);
320 }
321 if (retpolines) {
322 void *rseg = (void *)retpolines->sh_addr;
323 apply_retpolines(rseg, rseg + retpolines->sh_size);
324 }
325 if (returns) {
326 void *rseg = (void *)returns->sh_addr;
327 apply_returns(rseg, rseg + returns->sh_size);
328 }
329 if (alt) {
330 /* patch .altinstructions */
331 void *aseg = (void *)alt->sh_addr;
332 apply_alternatives(aseg, aseg + alt->sh_size);
333 }
334 if (calls || alt) {
335 struct callthunk_sites cs = {};
336
337 if (calls) {
338 cs.call_start = (void *)calls->sh_addr;
339 cs.call_end = (void *)calls->sh_addr + calls->sh_size;
340 }
341
342 if (alt) {
343 cs.alt_start = (void *)alt->sh_addr;
344 cs.alt_end = (void *)alt->sh_addr + alt->sh_size;
345 }
346
347 callthunks_patch_module_calls(&cs, me);
348 }
349 if (ibt_endbr) {
350 void *iseg = (void *)ibt_endbr->sh_addr;
351 apply_seal_endbr(iseg, iseg + ibt_endbr->sh_size);
352 }
353 if (locks) {
354 void *lseg = (void *)locks->sh_addr;
355 void *text = me->mem[MOD_TEXT].base;
356 void *text_end = text + me->mem[MOD_TEXT].size;
357 alternatives_smp_module_add(me, me->name,
358 lseg, lseg + locks->sh_size,
359 text, text_end);
360 }
361
362 if (orc && orc_ip)
363 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
364 (void *)orc->sh_addr, orc->sh_size);
365
366 return 0;
367}
368
369void module_arch_cleanup(struct module *mod)
370{
371 alternatives_smp_module_del(mod);
372}