Commit | Line | Data |
---|---|---|
1ccea77e | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
b700e7f0 SJ |
2 | /* |
3 | * core.c - Kernel Live Patching Core | |
4 | * | |
5 | * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com> | |
6 | * Copyright (C) 2014 SUSE | |
b700e7f0 SJ |
7 | */ |
8 | ||
9 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/kernel.h> | |
13 | #include <linux/mutex.h> | |
14 | #include <linux/slab.h> | |
b700e7f0 SJ |
15 | #include <linux/list.h> |
16 | #include <linux/kallsyms.h> | |
17 | #include <linux/livepatch.h> | |
425595a7 JY |
18 | #include <linux/elf.h> |
19 | #include <linux/moduleloader.h> | |
3ec24776 | 20 | #include <linux/completion.h> |
9f255b63 | 21 | #include <linux/memory.h> |
b56b36ee | 22 | #include <asm/cacheflush.h> |
10517429 | 23 | #include "core.h" |
c349cdca | 24 | #include "patch.h" |
d83a7cb3 | 25 | #include "transition.h" |
b700e7f0 | 26 | |
3c33f5b9 | 27 | /* |
d83a7cb3 JP |
28 | * klp_mutex is a coarse lock which serializes access to klp data. All |
29 | * accesses to klp-related variables and structures must have mutex protection, | |
30 | * except within the following functions which carefully avoid the need for it: | |
31 | * | |
32 | * - klp_ftrace_handler() | |
33 | * - klp_update_patch_state() | |
3c33f5b9 | 34 | */ |
d83a7cb3 | 35 | DEFINE_MUTEX(klp_mutex); |
3c33f5b9 | 36 | |
958ef1e3 PM |
37 | /* |
38 | * Actively used patches: enabled or in transition. Note that replaced | |
39 | * or disabled patches are not listed even though the related kernel | |
40 | * module still can be loaded. | |
41 | */ | |
68007289 | 42 | LIST_HEAD(klp_patches); |
b700e7f0 SJ |
43 | |
44 | static struct kobject *klp_root_kobj; | |
45 | ||
46 | static bool klp_is_module(struct klp_object *obj) | |
47 | { | |
48 | return obj->name; | |
49 | } | |
50 | ||
b700e7f0 SJ |
51 | /* sets obj->mod if object is not vmlinux and module is found */ |
52 | static void klp_find_object_module(struct klp_object *obj) | |
53 | { | |
8cb2c2dc PM |
54 | struct module *mod; |
55 | ||
b700e7f0 SJ |
56 | if (!klp_is_module(obj)) |
57 | return; | |
58 | ||
59 | mutex_lock(&module_mutex); | |
60 | /* | |
8cb2c2dc PM |
61 | * We do not want to block removal of patched modules and therefore |
62 | * we do not take a reference here. The patches are removed by | |
7e545d6e | 63 | * klp_module_going() instead. |
8cb2c2dc PM |
64 | */ |
65 | mod = find_module(obj->name); | |
66 | /* | |
7e545d6e JY |
67 | * Do not mess work of klp_module_coming() and klp_module_going(). |
68 | * Note that the patch might still be needed before klp_module_going() | |
8cb2c2dc PM |
69 | * is called. Module functions can be called even in the GOING state |
70 | * until mod->exit() finishes. This is especially important for | |
71 | * patches that modify semantic of the functions. | |
b700e7f0 | 72 | */ |
8cb2c2dc PM |
73 | if (mod && mod->klp_alive) |
74 | obj->mod = mod; | |
75 | ||
b700e7f0 SJ |
76 | mutex_unlock(&module_mutex); |
77 | } | |
78 | ||
b700e7f0 SJ |
79 | static bool klp_initialized(void) |
80 | { | |
e76ff06a | 81 | return !!klp_root_kobj; |
b700e7f0 SJ |
82 | } |
83 | ||
e1452b60 JB |
84 | static struct klp_func *klp_find_func(struct klp_object *obj, |
85 | struct klp_func *old_func) | |
86 | { | |
87 | struct klp_func *func; | |
88 | ||
89 | klp_for_each_func(obj, func) { | |
90 | if ((strcmp(old_func->old_name, func->old_name) == 0) && | |
91 | (old_func->old_sympos == func->old_sympos)) { | |
92 | return func; | |
93 | } | |
94 | } | |
95 | ||
96 | return NULL; | |
97 | } | |
98 | ||
99 | static struct klp_object *klp_find_object(struct klp_patch *patch, | |
100 | struct klp_object *old_obj) | |
101 | { | |
102 | struct klp_object *obj; | |
103 | ||
104 | klp_for_each_object(patch, obj) { | |
105 | if (klp_is_module(old_obj)) { | |
106 | if (klp_is_module(obj) && | |
107 | strcmp(old_obj->name, obj->name) == 0) { | |
108 | return obj; | |
109 | } | |
110 | } else if (!klp_is_module(obj)) { | |
111 | return obj; | |
112 | } | |
113 | } | |
114 | ||
115 | return NULL; | |
116 | } | |
117 | ||
b700e7f0 SJ |
118 | struct klp_find_arg { |
119 | const char *objname; | |
120 | const char *name; | |
121 | unsigned long addr; | |
b700e7f0 | 122 | unsigned long count; |
b2b018ef | 123 | unsigned long pos; |
b700e7f0 SJ |
124 | }; |
125 | ||
126 | static int klp_find_callback(void *data, const char *name, | |
127 | struct module *mod, unsigned long addr) | |
128 | { | |
129 | struct klp_find_arg *args = data; | |
130 | ||
131 | if ((mod && !args->objname) || (!mod && args->objname)) | |
132 | return 0; | |
133 | ||
134 | if (strcmp(args->name, name)) | |
135 | return 0; | |
136 | ||
137 | if (args->objname && strcmp(args->objname, mod->name)) | |
138 | return 0; | |
139 | ||
b700e7f0 SJ |
140 | args->addr = addr; |
141 | args->count++; | |
142 | ||
b2b018ef CA |
143 | /* |
144 | * Finish the search when the symbol is found for the desired position | |
145 | * or the position is not defined for a non-unique symbol. | |
146 | */ | |
147 | if ((args->pos && (args->count == args->pos)) || | |
148 | (!args->pos && (args->count > 1))) | |
149 | return 1; | |
150 | ||
b700e7f0 SJ |
151 | return 0; |
152 | } | |
153 | ||
154 | static int klp_find_object_symbol(const char *objname, const char *name, | |
b2b018ef | 155 | unsigned long sympos, unsigned long *addr) |
b700e7f0 SJ |
156 | { |
157 | struct klp_find_arg args = { | |
158 | .objname = objname, | |
159 | .name = name, | |
160 | .addr = 0, | |
b2b018ef CA |
161 | .count = 0, |
162 | .pos = sympos, | |
b700e7f0 SJ |
163 | }; |
164 | ||
9a1bd63c | 165 | mutex_lock(&module_mutex); |
72f04b50 ZC |
166 | if (objname) |
167 | module_kallsyms_on_each_symbol(klp_find_callback, &args); | |
168 | else | |
169 | kallsyms_on_each_symbol(klp_find_callback, &args); | |
9a1bd63c | 170 | mutex_unlock(&module_mutex); |
b700e7f0 | 171 | |
b2b018ef CA |
172 | /* |
173 | * Ensure an address was found. If sympos is 0, ensure symbol is unique; | |
174 | * otherwise ensure the symbol position count matches sympos. | |
175 | */ | |
176 | if (args.addr == 0) | |
b700e7f0 | 177 | pr_err("symbol '%s' not found in symbol table\n", name); |
b2b018ef | 178 | else if (args.count > 1 && sympos == 0) { |
f995b5f7 PM |
179 | pr_err("unresolvable ambiguity for symbol '%s' in object '%s'\n", |
180 | name, objname); | |
b2b018ef CA |
181 | } else if (sympos != args.count && sympos > 0) { |
182 | pr_err("symbol position %lu for symbol '%s' in object '%s' not found\n", | |
183 | sympos, name, objname ? objname : "vmlinux"); | |
184 | } else { | |
b700e7f0 SJ |
185 | *addr = args.addr; |
186 | return 0; | |
187 | } | |
188 | ||
189 | *addr = 0; | |
190 | return -EINVAL; | |
191 | } | |
192 | ||
425595a7 | 193 | static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod) |
b700e7f0 | 194 | { |
425595a7 JY |
195 | int i, cnt, vmlinux, ret; |
196 | char objname[MODULE_NAME_LEN]; | |
197 | char symname[KSYM_NAME_LEN]; | |
198 | char *strtab = pmod->core_kallsyms.strtab; | |
199 | Elf_Rela *relas; | |
200 | Elf_Sym *sym; | |
201 | unsigned long sympos, addr; | |
b700e7f0 | 202 | |
b2b018ef | 203 | /* |
425595a7 JY |
204 | * Since the field widths for objname and symname in the sscanf() |
205 | * call are hard-coded and correspond to MODULE_NAME_LEN and | |
206 | * KSYM_NAME_LEN respectively, we must make sure that MODULE_NAME_LEN | |
207 | * and KSYM_NAME_LEN have the values we expect them to have. | |
208 | * | |
209 | * Because the value of MODULE_NAME_LEN can differ among architectures, | |
210 | * we use the smallest/strictest upper bound possible (56, based on | |
211 | * the current definition of MODULE_NAME_LEN) to prevent overflows. | |
b2b018ef | 212 | */ |
425595a7 JY |
213 | BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128); |
214 | ||
215 | relas = (Elf_Rela *) relasec->sh_addr; | |
216 | /* For each rela in this klp relocation section */ | |
217 | for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) { | |
218 | sym = pmod->core_kallsyms.symtab + ELF_R_SYM(relas[i].r_info); | |
219 | if (sym->st_shndx != SHN_LIVEPATCH) { | |
77f8f39a | 220 | pr_err("symbol %s is not marked as a livepatch symbol\n", |
425595a7 JY |
221 | strtab + sym->st_name); |
222 | return -EINVAL; | |
223 | } | |
224 | ||
225 | /* Format: .klp.sym.objname.symname,sympos */ | |
226 | cnt = sscanf(strtab + sym->st_name, | |
227 | ".klp.sym.%55[^.].%127[^,],%lu", | |
228 | objname, symname, &sympos); | |
229 | if (cnt != 3) { | |
77f8f39a | 230 | pr_err("symbol %s has an incorrectly formatted name\n", |
425595a7 JY |
231 | strtab + sym->st_name); |
232 | return -EINVAL; | |
233 | } | |
234 | ||
235 | /* klp_find_object_symbol() treats a NULL objname as vmlinux */ | |
236 | vmlinux = !strcmp(objname, "vmlinux"); | |
237 | ret = klp_find_object_symbol(vmlinux ? NULL : objname, | |
238 | symname, sympos, &addr); | |
239 | if (ret) | |
240 | return ret; | |
241 | ||
242 | sym->st_value = addr; | |
243 | } | |
244 | ||
245 | return 0; | |
b700e7f0 SJ |
246 | } |
247 | ||
248 | static int klp_write_object_relocations(struct module *pmod, | |
249 | struct klp_object *obj) | |
250 | { | |
425595a7 JY |
251 | int i, cnt, ret = 0; |
252 | const char *objname, *secname; | |
253 | char sec_objname[MODULE_NAME_LEN]; | |
254 | Elf_Shdr *sec; | |
b700e7f0 SJ |
255 | |
256 | if (WARN_ON(!klp_is_object_loaded(obj))) | |
257 | return -EINVAL; | |
258 | ||
425595a7 | 259 | objname = klp_is_module(obj) ? obj->name : "vmlinux"; |
b700e7f0 | 260 | |
425595a7 JY |
261 | /* For each klp relocation section */ |
262 | for (i = 1; i < pmod->klp_info->hdr.e_shnum; i++) { | |
263 | sec = pmod->klp_info->sechdrs + i; | |
264 | secname = pmod->klp_info->secstrings + sec->sh_name; | |
265 | if (!(sec->sh_flags & SHF_RELA_LIVEPATCH)) | |
266 | continue; | |
b56b36ee | 267 | |
425595a7 JY |
268 | /* |
269 | * Format: .klp.rela.sec_objname.section_name | |
270 | * See comment in klp_resolve_symbols() for an explanation | |
271 | * of the selected field width value. | |
272 | */ | |
273 | cnt = sscanf(secname, ".klp.rela.%55[^.]", sec_objname); | |
274 | if (cnt != 1) { | |
77f8f39a | 275 | pr_err("section %s has an incorrectly formatted name\n", |
425595a7 JY |
276 | secname); |
277 | ret = -EINVAL; | |
278 | break; | |
279 | } | |
b56b36ee | 280 | |
425595a7 JY |
281 | if (strcmp(objname, sec_objname)) |
282 | continue; | |
b56b36ee | 283 | |
425595a7 | 284 | ret = klp_resolve_symbols(sec, pmod); |
064c89df | 285 | if (ret) |
425595a7 | 286 | break; |
064c89df | 287 | |
425595a7 JY |
288 | ret = apply_relocate_add(pmod->klp_info->sechdrs, |
289 | pmod->core_kallsyms.strtab, | |
290 | pmod->klp_info->symndx, i, pmod); | |
291 | if (ret) | |
292 | break; | |
b700e7f0 SJ |
293 | } |
294 | ||
b56b36ee | 295 | return ret; |
b700e7f0 SJ |
296 | } |
297 | ||
b700e7f0 SJ |
298 | /* |
299 | * Sysfs Interface | |
300 | * | |
301 | * /sys/kernel/livepatch | |
302 | * /sys/kernel/livepatch/<patch> | |
303 | * /sys/kernel/livepatch/<patch>/enabled | |
d83a7cb3 | 304 | * /sys/kernel/livepatch/<patch>/transition |
c99a2be7 | 305 | * /sys/kernel/livepatch/<patch>/force |
b700e7f0 | 306 | * /sys/kernel/livepatch/<patch>/<object> |
444f9e99 | 307 | * /sys/kernel/livepatch/<patch>/<object>/<function,sympos> |
b700e7f0 | 308 | */ |
26c3e98e | 309 | static int __klp_disable_patch(struct klp_patch *patch); |
b700e7f0 SJ |
310 | |
311 | static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr, | |
312 | const char *buf, size_t count) | |
313 | { | |
314 | struct klp_patch *patch; | |
315 | int ret; | |
68ae4b2b | 316 | bool enabled; |
b700e7f0 | 317 | |
68ae4b2b | 318 | ret = kstrtobool(buf, &enabled); |
b700e7f0 | 319 | if (ret) |
68ae4b2b | 320 | return ret; |
b700e7f0 SJ |
321 | |
322 | patch = container_of(kobj, struct klp_patch, kobj); | |
323 | ||
324 | mutex_lock(&klp_mutex); | |
325 | ||
68ae4b2b | 326 | if (patch->enabled == enabled) { |
b700e7f0 SJ |
327 | /* already in requested state */ |
328 | ret = -EINVAL; | |
958ef1e3 | 329 | goto out; |
b700e7f0 SJ |
330 | } |
331 | ||
958ef1e3 PM |
332 | /* |
333 | * Allow to reverse a pending transition in both ways. It might be | |
334 | * necessary to complete the transition without forcing and breaking | |
335 | * the system integrity. | |
336 | * | |
337 | * Do not allow to re-enable a disabled patch. | |
338 | */ | |
339 | if (patch == klp_transition_patch) | |
d83a7cb3 | 340 | klp_reverse_transition(); |
958ef1e3 | 341 | else if (!enabled) |
b700e7f0 | 342 | ret = __klp_disable_patch(patch); |
958ef1e3 PM |
343 | else |
344 | ret = -EINVAL; | |
b700e7f0 | 345 | |
958ef1e3 | 346 | out: |
b700e7f0 SJ |
347 | mutex_unlock(&klp_mutex); |
348 | ||
958ef1e3 PM |
349 | if (ret) |
350 | return ret; | |
b700e7f0 | 351 | return count; |
b700e7f0 SJ |
352 | } |
353 | ||
354 | static ssize_t enabled_show(struct kobject *kobj, | |
355 | struct kobj_attribute *attr, char *buf) | |
356 | { | |
357 | struct klp_patch *patch; | |
358 | ||
359 | patch = container_of(kobj, struct klp_patch, kobj); | |
0dade9f3 | 360 | return snprintf(buf, PAGE_SIZE-1, "%d\n", patch->enabled); |
b700e7f0 SJ |
361 | } |
362 | ||
d83a7cb3 JP |
363 | static ssize_t transition_show(struct kobject *kobj, |
364 | struct kobj_attribute *attr, char *buf) | |
365 | { | |
366 | struct klp_patch *patch; | |
367 | ||
368 | patch = container_of(kobj, struct klp_patch, kobj); | |
369 | return snprintf(buf, PAGE_SIZE-1, "%d\n", | |
370 | patch == klp_transition_patch); | |
b700e7f0 SJ |
371 | } |
372 | ||
c99a2be7 MB |
373 | static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr, |
374 | const char *buf, size_t count) | |
375 | { | |
376 | struct klp_patch *patch; | |
377 | int ret; | |
378 | bool val; | |
379 | ||
c99a2be7 MB |
380 | ret = kstrtobool(buf, &val); |
381 | if (ret) | |
382 | return ret; | |
383 | ||
8869016d MB |
384 | if (!val) |
385 | return count; | |
386 | ||
387 | mutex_lock(&klp_mutex); | |
388 | ||
389 | patch = container_of(kobj, struct klp_patch, kobj); | |
390 | if (patch != klp_transition_patch) { | |
391 | mutex_unlock(&klp_mutex); | |
392 | return -EINVAL; | |
393 | } | |
394 | ||
395 | klp_force_transition(); | |
396 | ||
397 | mutex_unlock(&klp_mutex); | |
c99a2be7 MB |
398 | |
399 | return count; | |
400 | } | |
401 | ||
b700e7f0 | 402 | static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled); |
d83a7cb3 | 403 | static struct kobj_attribute transition_kobj_attr = __ATTR_RO(transition); |
c99a2be7 | 404 | static struct kobj_attribute force_kobj_attr = __ATTR_WO(force); |
b700e7f0 SJ |
405 | static struct attribute *klp_patch_attrs[] = { |
406 | &enabled_kobj_attr.attr, | |
d83a7cb3 | 407 | &transition_kobj_attr.attr, |
c99a2be7 | 408 | &force_kobj_attr.attr, |
b700e7f0 SJ |
409 | NULL |
410 | }; | |
70283454 | 411 | ATTRIBUTE_GROUPS(klp_patch); |
b700e7f0 | 412 | |
e1452b60 JB |
413 | static void klp_free_object_dynamic(struct klp_object *obj) |
414 | { | |
415 | kfree(obj->name); | |
416 | kfree(obj); | |
417 | } | |
418 | ||
f68d67cf PM |
419 | static void klp_init_func_early(struct klp_object *obj, |
420 | struct klp_func *func); | |
421 | static void klp_init_object_early(struct klp_patch *patch, | |
422 | struct klp_object *obj); | |
4d141ab3 | 423 | |
f68d67cf PM |
424 | static struct klp_object *klp_alloc_object_dynamic(const char *name, |
425 | struct klp_patch *patch) | |
e1452b60 JB |
426 | { |
427 | struct klp_object *obj; | |
428 | ||
429 | obj = kzalloc(sizeof(*obj), GFP_KERNEL); | |
430 | if (!obj) | |
431 | return NULL; | |
432 | ||
433 | if (name) { | |
434 | obj->name = kstrdup(name, GFP_KERNEL); | |
435 | if (!obj->name) { | |
436 | kfree(obj); | |
437 | return NULL; | |
438 | } | |
439 | } | |
440 | ||
f68d67cf | 441 | klp_init_object_early(patch, obj); |
e1452b60 JB |
442 | obj->dynamic = true; |
443 | ||
444 | return obj; | |
445 | } | |
446 | ||
447 | static void klp_free_func_nop(struct klp_func *func) | |
448 | { | |
449 | kfree(func->old_name); | |
450 | kfree(func); | |
451 | } | |
452 | ||
453 | static struct klp_func *klp_alloc_func_nop(struct klp_func *old_func, | |
454 | struct klp_object *obj) | |
455 | { | |
456 | struct klp_func *func; | |
457 | ||
458 | func = kzalloc(sizeof(*func), GFP_KERNEL); | |
459 | if (!func) | |
460 | return NULL; | |
461 | ||
462 | if (old_func->old_name) { | |
463 | func->old_name = kstrdup(old_func->old_name, GFP_KERNEL); | |
464 | if (!func->old_name) { | |
465 | kfree(func); | |
466 | return NULL; | |
467 | } | |
468 | } | |
469 | ||
f68d67cf | 470 | klp_init_func_early(obj, func); |
e1452b60 JB |
471 | /* |
472 | * func->new_func is same as func->old_func. These addresses are | |
473 | * set when the object is loaded, see klp_init_object_loaded(). | |
474 | */ | |
475 | func->old_sympos = old_func->old_sympos; | |
476 | func->nop = true; | |
477 | ||
478 | return func; | |
479 | } | |
480 | ||
481 | static int klp_add_object_nops(struct klp_patch *patch, | |
482 | struct klp_object *old_obj) | |
483 | { | |
484 | struct klp_object *obj; | |
485 | struct klp_func *func, *old_func; | |
486 | ||
487 | obj = klp_find_object(patch, old_obj); | |
488 | ||
489 | if (!obj) { | |
f68d67cf | 490 | obj = klp_alloc_object_dynamic(old_obj->name, patch); |
e1452b60 JB |
491 | if (!obj) |
492 | return -ENOMEM; | |
e1452b60 JB |
493 | } |
494 | ||
495 | klp_for_each_func(old_obj, old_func) { | |
496 | func = klp_find_func(obj, old_func); | |
497 | if (func) | |
498 | continue; | |
499 | ||
500 | func = klp_alloc_func_nop(old_func, obj); | |
501 | if (!func) | |
502 | return -ENOMEM; | |
e1452b60 JB |
503 | } |
504 | ||
505 | return 0; | |
506 | } | |
507 | ||
508 | /* | |
509 | * Add 'nop' functions which simply return to the caller to run | |
510 | * the original function. The 'nop' functions are added to a | |
511 | * patch to facilitate a 'replace' mode. | |
512 | */ | |
513 | static int klp_add_nops(struct klp_patch *patch) | |
514 | { | |
515 | struct klp_patch *old_patch; | |
516 | struct klp_object *old_obj; | |
517 | ||
ecba29f4 | 518 | klp_for_each_patch(old_patch) { |
e1452b60 JB |
519 | klp_for_each_object(old_patch, old_obj) { |
520 | int err; | |
521 | ||
522 | err = klp_add_object_nops(patch, old_obj); | |
523 | if (err) | |
524 | return err; | |
525 | } | |
526 | } | |
527 | ||
528 | return 0; | |
529 | } | |
530 | ||
b700e7f0 SJ |
531 | static void klp_kobj_release_patch(struct kobject *kobj) |
532 | { | |
3ec24776 JP |
533 | struct klp_patch *patch; |
534 | ||
535 | patch = container_of(kobj, struct klp_patch, kobj); | |
536 | complete(&patch->finish); | |
b700e7f0 SJ |
537 | } |
538 | ||
539 | static struct kobj_type klp_ktype_patch = { | |
540 | .release = klp_kobj_release_patch, | |
541 | .sysfs_ops = &kobj_sysfs_ops, | |
70283454 | 542 | .default_groups = klp_patch_groups, |
b700e7f0 SJ |
543 | }; |
544 | ||
cad706df MB |
545 | static void klp_kobj_release_object(struct kobject *kobj) |
546 | { | |
e1452b60 JB |
547 | struct klp_object *obj; |
548 | ||
549 | obj = container_of(kobj, struct klp_object, kobj); | |
550 | ||
551 | if (obj->dynamic) | |
552 | klp_free_object_dynamic(obj); | |
cad706df MB |
553 | } |
554 | ||
555 | static struct kobj_type klp_ktype_object = { | |
556 | .release = klp_kobj_release_object, | |
557 | .sysfs_ops = &kobj_sysfs_ops, | |
558 | }; | |
559 | ||
b700e7f0 SJ |
560 | static void klp_kobj_release_func(struct kobject *kobj) |
561 | { | |
e1452b60 JB |
562 | struct klp_func *func; |
563 | ||
564 | func = container_of(kobj, struct klp_func, kobj); | |
565 | ||
566 | if (func->nop) | |
567 | klp_free_func_nop(func); | |
b700e7f0 SJ |
568 | } |
569 | ||
570 | static struct kobj_type klp_ktype_func = { | |
571 | .release = klp_kobj_release_func, | |
572 | .sysfs_ops = &kobj_sysfs_ops, | |
573 | }; | |
574 | ||
d697bad5 | 575 | static void __klp_free_funcs(struct klp_object *obj, bool nops_only) |
b700e7f0 | 576 | { |
e1452b60 | 577 | struct klp_func *func, *tmp_func; |
b700e7f0 | 578 | |
e1452b60 | 579 | klp_for_each_func_safe(obj, func, tmp_func) { |
d697bad5 PM |
580 | if (nops_only && !func->nop) |
581 | continue; | |
582 | ||
583 | list_del(&func->node); | |
4d141ab3 | 584 | kobject_put(&func->kobj); |
0430f78b | 585 | } |
b700e7f0 SJ |
586 | } |
587 | ||
588 | /* Clean up when a patched object is unloaded */ | |
589 | static void klp_free_object_loaded(struct klp_object *obj) | |
590 | { | |
591 | struct klp_func *func; | |
592 | ||
593 | obj->mod = NULL; | |
594 | ||
e1452b60 | 595 | klp_for_each_func(obj, func) { |
19514910 | 596 | func->old_func = NULL; |
e1452b60 JB |
597 | |
598 | if (func->nop) | |
599 | func->new_func = NULL; | |
600 | } | |
b700e7f0 SJ |
601 | } |
602 | ||
d697bad5 | 603 | static void __klp_free_objects(struct klp_patch *patch, bool nops_only) |
b700e7f0 | 604 | { |
e1452b60 | 605 | struct klp_object *obj, *tmp_obj; |
b700e7f0 | 606 | |
e1452b60 | 607 | klp_for_each_object_safe(patch, obj, tmp_obj) { |
d697bad5 PM |
608 | __klp_free_funcs(obj, nops_only); |
609 | ||
610 | if (nops_only && !obj->dynamic) | |
611 | continue; | |
612 | ||
613 | list_del(&obj->node); | |
4d141ab3 | 614 | kobject_put(&obj->kobj); |
b700e7f0 SJ |
615 | } |
616 | } | |
617 | ||
d697bad5 PM |
618 | static void klp_free_objects(struct klp_patch *patch) |
619 | { | |
620 | __klp_free_objects(patch, false); | |
621 | } | |
622 | ||
623 | static void klp_free_objects_dynamic(struct klp_patch *patch) | |
624 | { | |
625 | __klp_free_objects(patch, true); | |
626 | } | |
627 | ||
0430f78b PM |
628 | /* |
629 | * This function implements the free operations that can be called safely | |
630 | * under klp_mutex. | |
631 | * | |
632 | * The operation must be completed by calling klp_free_patch_finish() | |
633 | * outside klp_mutex. | |
634 | */ | |
958ef1e3 | 635 | void klp_free_patch_start(struct klp_patch *patch) |
b700e7f0 | 636 | { |
b700e7f0 SJ |
637 | if (!list_empty(&patch->list)) |
638 | list_del(&patch->list); | |
0430f78b PM |
639 | |
640 | klp_free_objects(patch); | |
641 | } | |
642 | ||
643 | /* | |
644 | * This function implements the free part that must be called outside | |
645 | * klp_mutex. | |
646 | * | |
647 | * It must be called after klp_free_patch_start(). And it has to be | |
648 | * the last function accessing the livepatch structures when the patch | |
649 | * gets disabled. | |
650 | */ | |
651 | static void klp_free_patch_finish(struct klp_patch *patch) | |
652 | { | |
653 | /* | |
654 | * Avoid deadlock with enabled_store() sysfs callback by | |
655 | * calling this outside klp_mutex. It is safe because | |
656 | * this is called when the patch gets disabled and it | |
657 | * cannot get enabled again. | |
658 | */ | |
4d141ab3 PM |
659 | kobject_put(&patch->kobj); |
660 | wait_for_completion(&patch->finish); | |
958ef1e3 PM |
661 | |
662 | /* Put the module after the last access to struct klp_patch. */ | |
663 | if (!patch->forced) | |
664 | module_put(patch->mod); | |
665 | } | |
666 | ||
667 | /* | |
668 | * The livepatch might be freed from sysfs interface created by the patch. | |
669 | * This work allows to wait until the interface is destroyed in a separate | |
670 | * context. | |
671 | */ | |
672 | static void klp_free_patch_work_fn(struct work_struct *work) | |
673 | { | |
674 | struct klp_patch *patch = | |
675 | container_of(work, struct klp_patch, free_work); | |
676 | ||
677 | klp_free_patch_finish(patch); | |
b700e7f0 SJ |
678 | } |
679 | ||
680 | static int klp_init_func(struct klp_object *obj, struct klp_func *func) | |
681 | { | |
e1452b60 JB |
682 | if (!func->old_name) |
683 | return -EINVAL; | |
684 | ||
685 | /* | |
686 | * NOPs get the address later. The patched module must be loaded, | |
687 | * see klp_init_object_loaded(). | |
688 | */ | |
689 | if (!func->new_func && !func->nop) | |
f09d9086 MB |
690 | return -EINVAL; |
691 | ||
6e9df95b KB |
692 | if (strlen(func->old_name) >= KSYM_NAME_LEN) |
693 | return -EINVAL; | |
694 | ||
3c33f5b9 | 695 | INIT_LIST_HEAD(&func->stack_node); |
0dade9f3 | 696 | func->patched = false; |
d83a7cb3 | 697 | func->transition = false; |
b700e7f0 | 698 | |
444f9e99 CA |
699 | /* The format for the sysfs directory is <function,sympos> where sympos |
700 | * is the nth occurrence of this symbol in kallsyms for the patched | |
701 | * object. If the user selects 0 for old_sympos, then 1 will be used | |
702 | * since a unique symbol will be the first occurrence. | |
703 | */ | |
4d141ab3 PM |
704 | return kobject_add(&func->kobj, &obj->kobj, "%s,%lu", |
705 | func->old_name, | |
706 | func->old_sympos ? func->old_sympos : 1); | |
b700e7f0 SJ |
707 | } |
708 | ||
255e732c JY |
709 | /* Arches may override this to finish any remaining arch-specific tasks */ |
710 | void __weak arch_klp_init_object_loaded(struct klp_patch *patch, | |
711 | struct klp_object *obj) | |
712 | { | |
713 | } | |
714 | ||
b700e7f0 SJ |
715 | /* parts of the initialization that is done only when the object is loaded */ |
716 | static int klp_init_object_loaded(struct klp_patch *patch, | |
717 | struct klp_object *obj) | |
718 | { | |
719 | struct klp_func *func; | |
720 | int ret; | |
721 | ||
9f255b63 JP |
722 | mutex_lock(&text_mutex); |
723 | ||
255e732c | 724 | module_disable_ro(patch->mod); |
425595a7 | 725 | ret = klp_write_object_relocations(patch->mod, obj); |
255e732c JY |
726 | if (ret) { |
727 | module_enable_ro(patch->mod, true); | |
9f255b63 | 728 | mutex_unlock(&text_mutex); |
425595a7 | 729 | return ret; |
255e732c JY |
730 | } |
731 | ||
732 | arch_klp_init_object_loaded(patch, obj); | |
733 | module_enable_ro(patch->mod, true); | |
b700e7f0 | 734 | |
9f255b63 JP |
735 | mutex_unlock(&text_mutex); |
736 | ||
8cdd043a | 737 | klp_for_each_func(obj, func) { |
b2b018ef CA |
738 | ret = klp_find_object_symbol(obj->name, func->old_name, |
739 | func->old_sympos, | |
19514910 | 740 | (unsigned long *)&func->old_func); |
b700e7f0 SJ |
741 | if (ret) |
742 | return ret; | |
f5e547f4 | 743 | |
19514910 | 744 | ret = kallsyms_lookup_size_offset((unsigned long)func->old_func, |
f5e547f4 JP |
745 | &func->old_size, NULL); |
746 | if (!ret) { | |
747 | pr_err("kallsyms size lookup failed for '%s'\n", | |
748 | func->old_name); | |
749 | return -ENOENT; | |
750 | } | |
751 | ||
e1452b60 JB |
752 | if (func->nop) |
753 | func->new_func = func->old_func; | |
754 | ||
f5e547f4 JP |
755 | ret = kallsyms_lookup_size_offset((unsigned long)func->new_func, |
756 | &func->new_size, NULL); | |
757 | if (!ret) { | |
758 | pr_err("kallsyms size lookup failed for '%s' replacement\n", | |
759 | func->old_name); | |
760 | return -ENOENT; | |
761 | } | |
b700e7f0 SJ |
762 | } |
763 | ||
764 | return 0; | |
765 | } | |
766 | ||
767 | static int klp_init_object(struct klp_patch *patch, struct klp_object *obj) | |
768 | { | |
769 | struct klp_func *func; | |
770 | int ret; | |
771 | const char *name; | |
772 | ||
6e9df95b KB |
773 | if (klp_is_module(obj) && strlen(obj->name) >= MODULE_NAME_LEN) |
774 | return -EINVAL; | |
775 | ||
0dade9f3 | 776 | obj->patched = false; |
8cb2c2dc | 777 | obj->mod = NULL; |
b700e7f0 SJ |
778 | |
779 | klp_find_object_module(obj); | |
780 | ||
781 | name = klp_is_module(obj) ? obj->name : "vmlinux"; | |
4d141ab3 | 782 | ret = kobject_add(&obj->kobj, &patch->kobj, "%s", name); |
cad706df MB |
783 | if (ret) |
784 | return ret; | |
b700e7f0 | 785 | |
8cdd043a | 786 | klp_for_each_func(obj, func) { |
b700e7f0 SJ |
787 | ret = klp_init_func(obj, func); |
788 | if (ret) | |
0430f78b | 789 | return ret; |
b700e7f0 SJ |
790 | } |
791 | ||
0430f78b | 792 | if (klp_is_object_loaded(obj)) |
b700e7f0 | 793 | ret = klp_init_object_loaded(patch, obj); |
b700e7f0 | 794 | |
b700e7f0 SJ |
795 | return ret; |
796 | } | |
797 | ||
f68d67cf PM |
798 | static void klp_init_func_early(struct klp_object *obj, |
799 | struct klp_func *func) | |
800 | { | |
801 | kobject_init(&func->kobj, &klp_ktype_func); | |
802 | list_add_tail(&func->node, &obj->func_list); | |
803 | } | |
804 | ||
805 | static void klp_init_object_early(struct klp_patch *patch, | |
806 | struct klp_object *obj) | |
807 | { | |
808 | INIT_LIST_HEAD(&obj->func_list); | |
809 | kobject_init(&obj->kobj, &klp_ktype_object); | |
810 | list_add_tail(&obj->node, &patch->obj_list); | |
811 | } | |
812 | ||
0430f78b | 813 | static int klp_init_patch_early(struct klp_patch *patch) |
b700e7f0 SJ |
814 | { |
815 | struct klp_object *obj; | |
0430f78b | 816 | struct klp_func *func; |
b700e7f0 SJ |
817 | |
818 | if (!patch->objs) | |
819 | return -EINVAL; | |
820 | ||
0430f78b | 821 | INIT_LIST_HEAD(&patch->list); |
20e55025 | 822 | INIT_LIST_HEAD(&patch->obj_list); |
4d141ab3 | 823 | kobject_init(&patch->kobj, &klp_ktype_patch); |
0dade9f3 | 824 | patch->enabled = false; |
68007289 | 825 | patch->forced = false; |
958ef1e3 | 826 | INIT_WORK(&patch->free_work, klp_free_patch_work_fn); |
3ec24776 | 827 | init_completion(&patch->finish); |
b700e7f0 | 828 | |
20e55025 | 829 | klp_for_each_object_static(patch, obj) { |
0430f78b PM |
830 | if (!obj->funcs) |
831 | return -EINVAL; | |
832 | ||
f68d67cf | 833 | klp_init_object_early(patch, obj); |
0430f78b | 834 | |
20e55025 | 835 | klp_for_each_func_static(obj, func) { |
f68d67cf | 836 | klp_init_func_early(obj, func); |
20e55025 | 837 | } |
0430f78b PM |
838 | } |
839 | ||
958ef1e3 PM |
840 | if (!try_module_get(patch->mod)) |
841 | return -ENODEV; | |
842 | ||
0430f78b PM |
843 | return 0; |
844 | } | |
845 | ||
846 | static int klp_init_patch(struct klp_patch *patch) | |
847 | { | |
848 | struct klp_object *obj; | |
849 | int ret; | |
850 | ||
4d141ab3 | 851 | ret = kobject_add(&patch->kobj, klp_root_kobj, "%s", patch->mod->name); |
958ef1e3 | 852 | if (ret) |
3ec24776 | 853 | return ret; |
b700e7f0 | 854 | |
e1452b60 JB |
855 | if (patch->replace) { |
856 | ret = klp_add_nops(patch); | |
857 | if (ret) | |
858 | return ret; | |
859 | } | |
860 | ||
8cdd043a | 861 | klp_for_each_object(patch, obj) { |
b700e7f0 SJ |
862 | ret = klp_init_object(patch, obj); |
863 | if (ret) | |
958ef1e3 | 864 | return ret; |
b700e7f0 SJ |
865 | } |
866 | ||
99590ba5 | 867 | list_add_tail(&patch->list, &klp_patches); |
b700e7f0 | 868 | |
3ec24776 | 869 | return 0; |
b700e7f0 | 870 | } |
b700e7f0 | 871 | |
26c3e98e PM |
872 | static int __klp_disable_patch(struct klp_patch *patch) |
873 | { | |
874 | struct klp_object *obj; | |
875 | ||
876 | if (WARN_ON(!patch->enabled)) | |
877 | return -EINVAL; | |
878 | ||
879 | if (klp_transition_patch) | |
880 | return -EBUSY; | |
881 | ||
26c3e98e PM |
882 | klp_init_transition(patch, KLP_UNPATCHED); |
883 | ||
884 | klp_for_each_object(patch, obj) | |
885 | if (obj->patched) | |
886 | klp_pre_unpatch_callback(obj); | |
887 | ||
888 | /* | |
889 | * Enforce the order of the func->transition writes in | |
890 | * klp_init_transition() and the TIF_PATCH_PENDING writes in | |
891 | * klp_start_transition(). In the rare case where klp_ftrace_handler() | |
892 | * is called shortly after klp_update_patch_state() switches the task, | |
893 | * this ensures the handler sees that func->transition is set. | |
894 | */ | |
895 | smp_wmb(); | |
896 | ||
897 | klp_start_transition(); | |
26c3e98e | 898 | patch->enabled = false; |
958ef1e3 | 899 | klp_try_complete_transition(); |
26c3e98e PM |
900 | |
901 | return 0; | |
902 | } | |
903 | ||
26c3e98e PM |
904 | static int __klp_enable_patch(struct klp_patch *patch) |
905 | { | |
906 | struct klp_object *obj; | |
907 | int ret; | |
908 | ||
909 | if (klp_transition_patch) | |
910 | return -EBUSY; | |
911 | ||
912 | if (WARN_ON(patch->enabled)) | |
913 | return -EINVAL; | |
914 | ||
26c3e98e PM |
915 | pr_notice("enabling patch '%s'\n", patch->mod->name); |
916 | ||
917 | klp_init_transition(patch, KLP_PATCHED); | |
918 | ||
919 | /* | |
920 | * Enforce the order of the func->transition writes in | |
921 | * klp_init_transition() and the ops->func_stack writes in | |
922 | * klp_patch_object(), so that klp_ftrace_handler() will see the | |
923 | * func->transition updates before the handler is registered and the | |
924 | * new funcs become visible to the handler. | |
925 | */ | |
926 | smp_wmb(); | |
927 | ||
928 | klp_for_each_object(patch, obj) { | |
929 | if (!klp_is_object_loaded(obj)) | |
930 | continue; | |
931 | ||
932 | ret = klp_pre_patch_callback(obj); | |
933 | if (ret) { | |
934 | pr_warn("pre-patch callback failed for object '%s'\n", | |
935 | klp_is_module(obj) ? obj->name : "vmlinux"); | |
936 | goto err; | |
937 | } | |
938 | ||
939 | ret = klp_patch_object(obj); | |
940 | if (ret) { | |
941 | pr_warn("failed to patch object '%s'\n", | |
942 | klp_is_module(obj) ? obj->name : "vmlinux"); | |
943 | goto err; | |
944 | } | |
945 | } | |
946 | ||
947 | klp_start_transition(); | |
26c3e98e | 948 | patch->enabled = true; |
958ef1e3 | 949 | klp_try_complete_transition(); |
26c3e98e PM |
950 | |
951 | return 0; | |
952 | err: | |
953 | pr_warn("failed to enable patch '%s'\n", patch->mod->name); | |
954 | ||
955 | klp_cancel_transition(); | |
956 | return ret; | |
957 | } | |
958 | ||
959 | /** | |
958ef1e3 PM |
960 | * klp_enable_patch() - enable the livepatch |
961 | * @patch: patch to be enabled | |
26c3e98e | 962 | * |
958ef1e3 PM |
963 | * Initializes the data structure associated with the patch, creates the sysfs |
964 | * interface, performs the needed symbol lookups and code relocations, | |
965 | * registers the patched functions with ftrace. | |
966 | * | |
967 | * This function is supposed to be called from the livepatch module_init() | |
968 | * callback. | |
26c3e98e PM |
969 | * |
970 | * Return: 0 on success, otherwise error | |
971 | */ | |
972 | int klp_enable_patch(struct klp_patch *patch) | |
973 | { | |
974 | int ret; | |
975 | ||
958ef1e3 PM |
976 | if (!patch || !patch->mod) |
977 | return -EINVAL; | |
978 | ||
979 | if (!is_livepatch_module(patch->mod)) { | |
980 | pr_err("module %s is not marked as a livepatch module\n", | |
981 | patch->mod->name); | |
982 | return -EINVAL; | |
983 | } | |
984 | ||
985 | if (!klp_initialized()) | |
986 | return -ENODEV; | |
987 | ||
988 | if (!klp_have_reliable_stack()) { | |
31adf230 PM |
989 | pr_warn("This architecture doesn't have support for the livepatch consistency model.\n"); |
990 | pr_warn("The livepatch transition may never complete.\n"); | |
958ef1e3 PM |
991 | } |
992 | ||
26c3e98e PM |
993 | mutex_lock(&klp_mutex); |
994 | ||
958ef1e3 PM |
995 | ret = klp_init_patch_early(patch); |
996 | if (ret) { | |
997 | mutex_unlock(&klp_mutex); | |
998 | return ret; | |
26c3e98e PM |
999 | } |
1000 | ||
958ef1e3 PM |
1001 | ret = klp_init_patch(patch); |
1002 | if (ret) | |
1003 | goto err; | |
1004 | ||
26c3e98e | 1005 | ret = __klp_enable_patch(patch); |
958ef1e3 PM |
1006 | if (ret) |
1007 | goto err; | |
1008 | ||
1009 | mutex_unlock(&klp_mutex); | |
1010 | ||
1011 | return 0; | |
26c3e98e PM |
1012 | |
1013 | err: | |
958ef1e3 PM |
1014 | klp_free_patch_start(patch); |
1015 | ||
26c3e98e | 1016 | mutex_unlock(&klp_mutex); |
958ef1e3 PM |
1017 | |
1018 | klp_free_patch_finish(patch); | |
1019 | ||
26c3e98e PM |
1020 | return ret; |
1021 | } | |
1022 | EXPORT_SYMBOL_GPL(klp_enable_patch); | |
1023 | ||
e1452b60 JB |
1024 | /* |
1025 | * This function removes replaced patches. | |
1026 | * | |
1027 | * We could be pretty aggressive here. It is called in the situation where | |
1028 | * these structures are no longer accessible. All functions are redirected | |
1029 | * by the klp_transition_patch. They use either a new code or they are in | |
1030 | * the original code because of the special nop function patches. | |
1031 | * | |
1032 | * The only exception is when the transition was forced. In this case, | |
1033 | * klp_ftrace_handler() might still see the replaced patch on the stack. | |
1034 | * Fortunately, it is carefully designed to work with removed functions | |
1035 | * thanks to RCU. We only have to keep the patches on the system. Also | |
1036 | * this is handled transparently by patch->module_put. | |
1037 | */ | |
1038 | void klp_discard_replaced_patches(struct klp_patch *new_patch) | |
1039 | { | |
1040 | struct klp_patch *old_patch, *tmp_patch; | |
1041 | ||
ecba29f4 | 1042 | klp_for_each_patch_safe(old_patch, tmp_patch) { |
e1452b60 JB |
1043 | if (old_patch == new_patch) |
1044 | return; | |
1045 | ||
1046 | old_patch->enabled = false; | |
1047 | klp_unpatch_objects(old_patch); | |
1048 | klp_free_patch_start(old_patch); | |
1049 | schedule_work(&old_patch->free_work); | |
1050 | } | |
1051 | } | |
1052 | ||
d697bad5 PM |
1053 | /* |
1054 | * This function removes the dynamically allocated 'nop' functions. | |
1055 | * | |
1056 | * We could be pretty aggressive. NOPs do not change the existing | |
1057 | * behavior except for adding unnecessary delay by the ftrace handler. | |
1058 | * | |
1059 | * It is safe even when the transition was forced. The ftrace handler | |
1060 | * will see a valid ops->func_stack entry thanks to RCU. | |
1061 | * | |
1062 | * We could even free the NOPs structures. They must be the last entry | |
1063 | * in ops->func_stack. Therefore unregister_ftrace_function() is called. | |
1064 | * It does the same as klp_synchronize_transition() to make sure that | |
1065 | * nobody is inside the ftrace handler once the operation finishes. | |
1066 | * | |
1067 | * IMPORTANT: It must be called right after removing the replaced patches! | |
1068 | */ | |
1069 | void klp_discard_nops(struct klp_patch *new_patch) | |
1070 | { | |
1071 | klp_unpatch_objects_dynamic(klp_transition_patch); | |
1072 | klp_free_objects_dynamic(klp_transition_patch); | |
1073 | } | |
1074 | ||
ef8daf8e JL |
1075 | /* |
1076 | * Remove parts of patches that touch a given kernel module. The list of | |
1077 | * patches processed might be limited. When limit is NULL, all patches | |
1078 | * will be handled. | |
1079 | */ | |
1080 | static void klp_cleanup_module_patches_limited(struct module *mod, | |
1081 | struct klp_patch *limit) | |
1082 | { | |
1083 | struct klp_patch *patch; | |
1084 | struct klp_object *obj; | |
1085 | ||
ecba29f4 | 1086 | klp_for_each_patch(patch) { |
ef8daf8e JL |
1087 | if (patch == limit) |
1088 | break; | |
1089 | ||
1090 | klp_for_each_object(patch, obj) { | |
1091 | if (!klp_is_module(obj) || strcmp(obj->name, mod->name)) | |
1092 | continue; | |
1093 | ||
a087cdd4 PM |
1094 | if (patch != klp_transition_patch) |
1095 | klp_pre_unpatch_callback(obj); | |
fc41efc1 | 1096 | |
a087cdd4 PM |
1097 | pr_notice("reverting patch '%s' on unloading module '%s'\n", |
1098 | patch->mod->name, obj->mod->name); | |
1099 | klp_unpatch_object(obj); | |
fc41efc1 | 1100 | |
a087cdd4 | 1101 | klp_post_unpatch_callback(obj); |
ef8daf8e JL |
1102 | |
1103 | klp_free_object_loaded(obj); | |
1104 | break; | |
1105 | } | |
1106 | } | |
1107 | } | |
1108 | ||
7e545d6e | 1109 | int klp_module_coming(struct module *mod) |
b700e7f0 | 1110 | { |
b700e7f0 | 1111 | int ret; |
7e545d6e JY |
1112 | struct klp_patch *patch; |
1113 | struct klp_object *obj; | |
b700e7f0 | 1114 | |
7e545d6e JY |
1115 | if (WARN_ON(mod->state != MODULE_STATE_COMING)) |
1116 | return -EINVAL; | |
b700e7f0 | 1117 | |
7e545d6e JY |
1118 | mutex_lock(&klp_mutex); |
1119 | /* | |
1120 | * Each module has to know that klp_module_coming() | |
1121 | * has been called. We never know what module will | |
1122 | * get patched by a new patch. | |
1123 | */ | |
1124 | mod->klp_alive = true; | |
b700e7f0 | 1125 | |
ecba29f4 | 1126 | klp_for_each_patch(patch) { |
7e545d6e JY |
1127 | klp_for_each_object(patch, obj) { |
1128 | if (!klp_is_module(obj) || strcmp(obj->name, mod->name)) | |
1129 | continue; | |
b700e7f0 | 1130 | |
7e545d6e | 1131 | obj->mod = mod; |
b700e7f0 | 1132 | |
7e545d6e JY |
1133 | ret = klp_init_object_loaded(patch, obj); |
1134 | if (ret) { | |
1135 | pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n", | |
1136 | patch->mod->name, obj->mod->name, ret); | |
1137 | goto err; | |
1138 | } | |
b700e7f0 | 1139 | |
7e545d6e JY |
1140 | pr_notice("applying patch '%s' to loading module '%s'\n", |
1141 | patch->mod->name, obj->mod->name); | |
1142 | ||
93862e38 JL |
1143 | ret = klp_pre_patch_callback(obj); |
1144 | if (ret) { | |
1145 | pr_warn("pre-patch callback failed for object '%s'\n", | |
1146 | obj->name); | |
1147 | goto err; | |
1148 | } | |
1149 | ||
0dade9f3 | 1150 | ret = klp_patch_object(obj); |
7e545d6e JY |
1151 | if (ret) { |
1152 | pr_warn("failed to apply patch '%s' to module '%s' (%d)\n", | |
1153 | patch->mod->name, obj->mod->name, ret); | |
93862e38 | 1154 | |
5aaf1ab5 | 1155 | klp_post_unpatch_callback(obj); |
7e545d6e JY |
1156 | goto err; |
1157 | } | |
1158 | ||
93862e38 JL |
1159 | if (patch != klp_transition_patch) |
1160 | klp_post_patch_callback(obj); | |
1161 | ||
7e545d6e JY |
1162 | break; |
1163 | } | |
1164 | } | |
b700e7f0 | 1165 | |
7e545d6e | 1166 | mutex_unlock(&klp_mutex); |
b700e7f0 | 1167 | |
7e545d6e | 1168 | return 0; |
b700e7f0 | 1169 | |
7e545d6e JY |
1170 | err: |
1171 | /* | |
1172 | * If a patch is unsuccessfully applied, return | |
1173 | * error to the module loader. | |
1174 | */ | |
1175 | pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n", | |
1176 | patch->mod->name, obj->mod->name, obj->mod->name); | |
1177 | mod->klp_alive = false; | |
4ff96fb5 | 1178 | obj->mod = NULL; |
ef8daf8e | 1179 | klp_cleanup_module_patches_limited(mod, patch); |
7e545d6e JY |
1180 | mutex_unlock(&klp_mutex); |
1181 | ||
1182 | return ret; | |
b700e7f0 SJ |
1183 | } |
1184 | ||
7e545d6e | 1185 | void klp_module_going(struct module *mod) |
b700e7f0 | 1186 | { |
7e545d6e JY |
1187 | if (WARN_ON(mod->state != MODULE_STATE_GOING && |
1188 | mod->state != MODULE_STATE_COMING)) | |
1189 | return; | |
b700e7f0 SJ |
1190 | |
1191 | mutex_lock(&klp_mutex); | |
8cb2c2dc | 1192 | /* |
7e545d6e JY |
1193 | * Each module has to know that klp_module_going() |
1194 | * has been called. We never know what module will | |
1195 | * get patched by a new patch. | |
8cb2c2dc | 1196 | */ |
7e545d6e | 1197 | mod->klp_alive = false; |
8cb2c2dc | 1198 | |
ef8daf8e | 1199 | klp_cleanup_module_patches_limited(mod, NULL); |
b700e7f0 SJ |
1200 | |
1201 | mutex_unlock(&klp_mutex); | |
b700e7f0 SJ |
1202 | } |
1203 | ||
26029d88 | 1204 | static int __init klp_init(void) |
b700e7f0 | 1205 | { |
b700e7f0 | 1206 | klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj); |
7e545d6e JY |
1207 | if (!klp_root_kobj) |
1208 | return -ENOMEM; | |
b700e7f0 SJ |
1209 | |
1210 | return 0; | |
b700e7f0 SJ |
1211 | } |
1212 | ||
1213 | module_init(klp_init); |