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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 /* Add the value, subtract its position */
118 *location += sym->st_value - (uint32_t)location;
119 break;
120 default:
121 pr_err("%s: Unknown relocation: %u\n",
122 me->name, ELF32_R_TYPE(rel[i].r_info));
123 return -ENOEXEC;
124 }
125 }
126 return 0;
127}
128#else /*X86_64*/
129static int __apply_relocate_add(Elf64_Shdr *sechdrs,
130 const char *strtab,
131 unsigned int symindex,
132 unsigned int relsec,
133 struct module *me,
134 void *(*write)(void *dest, const void *src, size_t len))
135{
136 unsigned int i;
137 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
138 Elf64_Sym *sym;
139 void *loc;
140 u64 val;
141
142 DEBUGP("Applying relocate section %u to %u\n",
143 relsec, sechdrs[relsec].sh_info);
144 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
145 /* This is where to make the change */
146 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
147 + rel[i].r_offset;
148
149 /* This is the symbol it is referring to. Note that all
150 undefined symbols have been resolved. */
151 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
152 + ELF64_R_SYM(rel[i].r_info);
153
154 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
155 (int)ELF64_R_TYPE(rel[i].r_info),
156 sym->st_value, rel[i].r_addend, (u64)loc);
157
158 val = sym->st_value + rel[i].r_addend;
159
160 switch (ELF64_R_TYPE(rel[i].r_info)) {
161 case R_X86_64_NONE:
162 break;
163 case R_X86_64_64:
164 if (*(u64 *)loc != 0)
165 goto invalid_relocation;
166 write(loc, &val, 8);
167 break;
168 case R_X86_64_32:
169 if (*(u32 *)loc != 0)
170 goto invalid_relocation;
171 write(loc, &val, 4);
172 if (val != *(u32 *)loc)
173 goto overflow;
174 break;
175 case R_X86_64_32S:
176 if (*(s32 *)loc != 0)
177 goto invalid_relocation;
178 write(loc, &val, 4);
179 if ((s64)val != *(s32 *)loc)
180 goto overflow;
181 break;
182 case R_X86_64_PC32:
183 case R_X86_64_PLT32:
184 if (*(u32 *)loc != 0)
185 goto invalid_relocation;
186 val -= (u64)loc;
187 write(loc, &val, 4);
188#if 0
189 if ((s64)val != *(s32 *)loc)
190 goto overflow;
191#endif
192 break;
193 case R_X86_64_PC64:
194 if (*(u64 *)loc != 0)
195 goto invalid_relocation;
196 val -= (u64)loc;
197 write(loc, &val, 8);
198 break;
199 default:
200 pr_err("%s: Unknown rela relocation: %llu\n",
201 me->name, ELF64_R_TYPE(rel[i].r_info));
202 return -ENOEXEC;
203 }
204 }
205 return 0;
206
207invalid_relocation:
208 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
209 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
210 return -ENOEXEC;
211
212overflow:
213 pr_err("overflow in relocation type %d val %Lx\n",
214 (int)ELF64_R_TYPE(rel[i].r_info), val);
215 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
216 me->name);
217 return -ENOEXEC;
218}
219
220int apply_relocate_add(Elf64_Shdr *sechdrs,
221 const char *strtab,
222 unsigned int symindex,
223 unsigned int relsec,
224 struct module *me)
225{
226 int ret;
227 bool early = me->state == MODULE_STATE_UNFORMED;
228 void *(*write)(void *, const void *, size_t) = memcpy;
229
230 if (!early) {
231 write = text_poke;
232 mutex_lock(&text_mutex);
233 }
234
235 ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
236 write);
237
238 if (!early) {
239 text_poke_sync();
240 mutex_unlock(&text_mutex);
241 }
242
243 return ret;
244}
245
246#endif
247
248int module_finalize(const Elf_Ehdr *hdr,
249 const Elf_Shdr *sechdrs,
250 struct module *me)
251{
252 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
253 *para = NULL, *orc = NULL, *orc_ip = NULL;
254 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
255
256 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
257 if (!strcmp(".text", secstrings + s->sh_name))
258 text = s;
259 if (!strcmp(".altinstructions", secstrings + s->sh_name))
260 alt = s;
261 if (!strcmp(".smp_locks", secstrings + s->sh_name))
262 locks = s;
263 if (!strcmp(".parainstructions", secstrings + s->sh_name))
264 para = s;
265 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
266 orc = s;
267 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
268 orc_ip = s;
269 }
270
271 if (alt) {
272 /* patch .altinstructions */
273 void *aseg = (void *)alt->sh_addr;
274 apply_alternatives(aseg, aseg + alt->sh_size);
275 }
276 if (locks && text) {
277 void *lseg = (void *)locks->sh_addr;
278 void *tseg = (void *)text->sh_addr;
279 alternatives_smp_module_add(me, me->name,
280 lseg, lseg + locks->sh_size,
281 tseg, tseg + text->sh_size);
282 }
283
284 if (para) {
285 void *pseg = (void *)para->sh_addr;
286 apply_paravirt(pseg, pseg + para->sh_size);
287 }
288
289 /* make jump label nops */
290 jump_label_apply_nops(me);
291
292 if (orc && orc_ip)
293 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
294 (void *)orc->sh_addr, orc->sh_size);
295
296 return 0;
297}
298
299void module_arch_cleanup(struct module *mod)
300{
301 alternatives_smp_module_del(mod);
302}
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 __apply_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{
139 unsigned int i;
140 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
141 Elf64_Sym *sym;
142 void *loc;
143 u64 val;
144
145 DEBUGP("Applying relocate section %u to %u\n",
146 relsec, sechdrs[relsec].sh_info);
147 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
148 /* This is where to make the change */
149 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
150 + rel[i].r_offset;
151
152 /* This is the symbol it is referring to. Note that all
153 undefined symbols have been resolved. */
154 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
155 + ELF64_R_SYM(rel[i].r_info);
156
157 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
158 (int)ELF64_R_TYPE(rel[i].r_info),
159 sym->st_value, rel[i].r_addend, (u64)loc);
160
161 val = sym->st_value + rel[i].r_addend;
162
163 switch (ELF64_R_TYPE(rel[i].r_info)) {
164 case R_X86_64_NONE:
165 break;
166 case R_X86_64_64:
167 if (*(u64 *)loc != 0)
168 goto invalid_relocation;
169 write(loc, &val, 8);
170 break;
171 case R_X86_64_32:
172 if (*(u32 *)loc != 0)
173 goto invalid_relocation;
174 write(loc, &val, 4);
175 if (val != *(u32 *)loc)
176 goto overflow;
177 break;
178 case R_X86_64_32S:
179 if (*(s32 *)loc != 0)
180 goto invalid_relocation;
181 write(loc, &val, 4);
182 if ((s64)val != *(s32 *)loc)
183 goto overflow;
184 break;
185 case R_X86_64_PC32:
186 case R_X86_64_PLT32:
187 if (*(u32 *)loc != 0)
188 goto invalid_relocation;
189 val -= (u64)loc;
190 write(loc, &val, 4);
191#if 0
192 if ((s64)val != *(s32 *)loc)
193 goto overflow;
194#endif
195 break;
196 case R_X86_64_PC64:
197 if (*(u64 *)loc != 0)
198 goto invalid_relocation;
199 val -= (u64)loc;
200 write(loc, &val, 8);
201 break;
202 default:
203 pr_err("%s: Unknown rela relocation: %llu\n",
204 me->name, ELF64_R_TYPE(rel[i].r_info));
205 return -ENOEXEC;
206 }
207 }
208 return 0;
209
210invalid_relocation:
211 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
212 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
213 return -ENOEXEC;
214
215overflow:
216 pr_err("overflow in relocation type %d val %Lx\n",
217 (int)ELF64_R_TYPE(rel[i].r_info), val);
218 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
219 me->name);
220 return -ENOEXEC;
221}
222
223int apply_relocate_add(Elf64_Shdr *sechdrs,
224 const char *strtab,
225 unsigned int symindex,
226 unsigned int relsec,
227 struct module *me)
228{
229 int ret;
230 bool early = me->state == MODULE_STATE_UNFORMED;
231 void *(*write)(void *, const void *, size_t) = memcpy;
232
233 if (!early) {
234 write = text_poke;
235 mutex_lock(&text_mutex);
236 }
237
238 ret = __apply_relocate_add(sechdrs, strtab, symindex, relsec, me,
239 write);
240
241 if (!early) {
242 text_poke_sync();
243 mutex_unlock(&text_mutex);
244 }
245
246 return ret;
247}
248
249#endif
250
251int module_finalize(const Elf_Ehdr *hdr,
252 const Elf_Shdr *sechdrs,
253 struct module *me)
254{
255 const Elf_Shdr *s, *alt = NULL, *locks = NULL,
256 *para = NULL, *orc = NULL, *orc_ip = NULL,
257 *retpolines = NULL, *returns = NULL, *ibt_endbr = NULL,
258 *calls = NULL, *cfi = NULL;
259 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
260
261 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
262 if (!strcmp(".altinstructions", secstrings + s->sh_name))
263 alt = s;
264 if (!strcmp(".smp_locks", secstrings + s->sh_name))
265 locks = s;
266 if (!strcmp(".parainstructions", secstrings + s->sh_name))
267 para = s;
268 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
269 orc = s;
270 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
271 orc_ip = s;
272 if (!strcmp(".retpoline_sites", secstrings + s->sh_name))
273 retpolines = s;
274 if (!strcmp(".return_sites", secstrings + s->sh_name))
275 returns = s;
276 if (!strcmp(".call_sites", secstrings + s->sh_name))
277 calls = s;
278 if (!strcmp(".cfi_sites", secstrings + s->sh_name))
279 cfi = s;
280 if (!strcmp(".ibt_endbr_seal", secstrings + s->sh_name))
281 ibt_endbr = s;
282 }
283
284 /*
285 * See alternative_instructions() for the ordering rules between the
286 * various patching types.
287 */
288 if (para) {
289 void *pseg = (void *)para->sh_addr;
290 apply_paravirt(pseg, pseg + para->sh_size);
291 }
292 if (retpolines || cfi) {
293 void *rseg = NULL, *cseg = NULL;
294 unsigned int rsize = 0, csize = 0;
295
296 if (retpolines) {
297 rseg = (void *)retpolines->sh_addr;
298 rsize = retpolines->sh_size;
299 }
300
301 if (cfi) {
302 cseg = (void *)cfi->sh_addr;
303 csize = cfi->sh_size;
304 }
305
306 apply_fineibt(rseg, rseg + rsize, cseg, cseg + csize);
307 }
308 if (retpolines) {
309 void *rseg = (void *)retpolines->sh_addr;
310 apply_retpolines(rseg, rseg + retpolines->sh_size);
311 }
312 if (returns) {
313 void *rseg = (void *)returns->sh_addr;
314 apply_returns(rseg, rseg + returns->sh_size);
315 }
316 if (alt) {
317 /* patch .altinstructions */
318 void *aseg = (void *)alt->sh_addr;
319 apply_alternatives(aseg, aseg + alt->sh_size);
320 }
321 if (calls || para) {
322 struct callthunk_sites cs = {};
323
324 if (calls) {
325 cs.call_start = (void *)calls->sh_addr;
326 cs.call_end = (void *)calls->sh_addr + calls->sh_size;
327 }
328
329 if (para) {
330 cs.pv_start = (void *)para->sh_addr;
331 cs.pv_end = (void *)para->sh_addr + para->sh_size;
332 }
333
334 callthunks_patch_module_calls(&cs, me);
335 }
336 if (ibt_endbr) {
337 void *iseg = (void *)ibt_endbr->sh_addr;
338 apply_ibt_endbr(iseg, iseg + ibt_endbr->sh_size);
339 }
340 if (locks) {
341 void *lseg = (void *)locks->sh_addr;
342 void *text = me->core_layout.base;
343 void *text_end = text + me->core_layout.text_size;
344 alternatives_smp_module_add(me, me->name,
345 lseg, lseg + locks->sh_size,
346 text, text_end);
347 }
348
349 if (orc && orc_ip)
350 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
351 (void *)orc->sh_addr, orc->sh_size);
352
353 return 0;
354}
355
356void module_arch_cleanup(struct module *mod)
357{
358 alternatives_smp_module_del(mod);
359}