Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 1 | /* |
| 2 | * core.c - Kernel Live Patching Core |
| 3 | * |
| 4 | * Copyright (C) 2014 Seth Jennings <sjenning@redhat.com> |
| 5 | * Copyright (C) 2014 SUSE |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU General Public License |
| 9 | * as published by the Free Software Foundation; either version 2 |
| 10 | * of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, see <http://www.gnu.org/licenses/>. |
| 19 | */ |
| 20 | |
| 21 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 22 | |
| 23 | #include <linux/module.h> |
| 24 | #include <linux/kernel.h> |
| 25 | #include <linux/mutex.h> |
| 26 | #include <linux/slab.h> |
| 27 | #include <linux/ftrace.h> |
| 28 | #include <linux/list.h> |
| 29 | #include <linux/kallsyms.h> |
| 30 | #include <linux/livepatch.h> |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 31 | #include <linux/elf.h> |
| 32 | #include <linux/moduleloader.h> |
Josh Poimboeuf | b56b36e | 2015-12-03 16:33:26 -0600 | [diff] [blame] | 33 | #include <asm/cacheflush.h> |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 34 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 35 | /** |
| 36 | * struct klp_ops - structure for tracking registered ftrace ops structs |
| 37 | * |
| 38 | * A single ftrace_ops is shared between all enabled replacement functions |
| 39 | * (klp_func structs) which have the same old_addr. This allows the switch |
| 40 | * between function versions to happen instantaneously by updating the klp_ops |
| 41 | * struct's func_stack list. The winner is the klp_func at the top of the |
| 42 | * func_stack (front of the list). |
| 43 | * |
| 44 | * @node: node for the global klp_ops list |
| 45 | * @func_stack: list head for the stack of klp_func's (active func is on top) |
| 46 | * @fops: registered ftrace ops struct |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 47 | */ |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 48 | struct klp_ops { |
| 49 | struct list_head node; |
| 50 | struct list_head func_stack; |
| 51 | struct ftrace_ops fops; |
| 52 | }; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 53 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 54 | /* |
| 55 | * The klp_mutex protects the global lists and state transitions of any |
| 56 | * structure reachable from them. References to any structure must be obtained |
| 57 | * under mutex protection (except in klp_ftrace_handler(), which uses RCU to |
| 58 | * ensure it gets consistent data). |
| 59 | */ |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 60 | static DEFINE_MUTEX(klp_mutex); |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 61 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 62 | static LIST_HEAD(klp_patches); |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 63 | static LIST_HEAD(klp_ops); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 64 | |
| 65 | static struct kobject *klp_root_kobj; |
| 66 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 67 | static struct klp_ops *klp_find_ops(unsigned long old_addr) |
| 68 | { |
| 69 | struct klp_ops *ops; |
| 70 | struct klp_func *func; |
| 71 | |
| 72 | list_for_each_entry(ops, &klp_ops, node) { |
| 73 | func = list_first_entry(&ops->func_stack, struct klp_func, |
| 74 | stack_node); |
| 75 | if (func->old_addr == old_addr) |
| 76 | return ops; |
| 77 | } |
| 78 | |
| 79 | return NULL; |
| 80 | } |
| 81 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 82 | static bool klp_is_module(struct klp_object *obj) |
| 83 | { |
| 84 | return obj->name; |
| 85 | } |
| 86 | |
| 87 | static bool klp_is_object_loaded(struct klp_object *obj) |
| 88 | { |
| 89 | return !obj->name || obj->mod; |
| 90 | } |
| 91 | |
| 92 | /* sets obj->mod if object is not vmlinux and module is found */ |
| 93 | static void klp_find_object_module(struct klp_object *obj) |
| 94 | { |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 95 | struct module *mod; |
| 96 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 97 | if (!klp_is_module(obj)) |
| 98 | return; |
| 99 | |
| 100 | mutex_lock(&module_mutex); |
| 101 | /* |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 102 | * We do not want to block removal of patched modules and therefore |
| 103 | * we do not take a reference here. The patches are removed by |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 104 | * klp_module_going() instead. |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 105 | */ |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 106 | mod = find_module(obj->name); |
| 107 | /* |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 108 | * Do not mess work of klp_module_coming() and klp_module_going(). |
| 109 | * Note that the patch might still be needed before klp_module_going() |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 110 | * is called. Module functions can be called even in the GOING state |
| 111 | * until mod->exit() finishes. This is especially important for |
| 112 | * patches that modify semantic of the functions. |
| 113 | */ |
| 114 | if (mod && mod->klp_alive) |
| 115 | obj->mod = mod; |
| 116 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 117 | mutex_unlock(&module_mutex); |
| 118 | } |
| 119 | |
| 120 | /* klp_mutex must be held by caller */ |
| 121 | static bool klp_is_patch_registered(struct klp_patch *patch) |
| 122 | { |
| 123 | struct klp_patch *mypatch; |
| 124 | |
| 125 | list_for_each_entry(mypatch, &klp_patches, list) |
| 126 | if (mypatch == patch) |
| 127 | return true; |
| 128 | |
| 129 | return false; |
| 130 | } |
| 131 | |
| 132 | static bool klp_initialized(void) |
| 133 | { |
Nicholas Mc Guire | e76ff06 | 2015-05-11 07:52:29 +0200 | [diff] [blame] | 134 | return !!klp_root_kobj; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 135 | } |
| 136 | |
| 137 | struct klp_find_arg { |
| 138 | const char *objname; |
| 139 | const char *name; |
| 140 | unsigned long addr; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 141 | unsigned long count; |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 142 | unsigned long pos; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 143 | }; |
| 144 | |
| 145 | static int klp_find_callback(void *data, const char *name, |
| 146 | struct module *mod, unsigned long addr) |
| 147 | { |
| 148 | struct klp_find_arg *args = data; |
| 149 | |
| 150 | if ((mod && !args->objname) || (!mod && args->objname)) |
| 151 | return 0; |
| 152 | |
| 153 | if (strcmp(args->name, name)) |
| 154 | return 0; |
| 155 | |
| 156 | if (args->objname && strcmp(args->objname, mod->name)) |
| 157 | return 0; |
| 158 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 159 | args->addr = addr; |
| 160 | args->count++; |
| 161 | |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 162 | /* |
| 163 | * Finish the search when the symbol is found for the desired position |
| 164 | * or the position is not defined for a non-unique symbol. |
| 165 | */ |
| 166 | if ((args->pos && (args->count == args->pos)) || |
| 167 | (!args->pos && (args->count > 1))) |
| 168 | return 1; |
| 169 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 170 | return 0; |
| 171 | } |
| 172 | |
| 173 | static int klp_find_object_symbol(const char *objname, const char *name, |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 174 | unsigned long sympos, unsigned long *addr) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 175 | { |
| 176 | struct klp_find_arg args = { |
| 177 | .objname = objname, |
| 178 | .name = name, |
| 179 | .addr = 0, |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 180 | .count = 0, |
| 181 | .pos = sympos, |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 182 | }; |
| 183 | |
Miroslav Benes | 9a1bd63 | 2015-06-01 17:48:37 +0200 | [diff] [blame] | 184 | mutex_lock(&module_mutex); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 185 | kallsyms_on_each_symbol(klp_find_callback, &args); |
Miroslav Benes | 9a1bd63 | 2015-06-01 17:48:37 +0200 | [diff] [blame] | 186 | mutex_unlock(&module_mutex); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 187 | |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 188 | /* |
| 189 | * Ensure an address was found. If sympos is 0, ensure symbol is unique; |
| 190 | * otherwise ensure the symbol position count matches sympos. |
| 191 | */ |
| 192 | if (args.addr == 0) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 193 | pr_err("symbol '%s' not found in symbol table\n", name); |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 194 | else if (args.count > 1 && sympos == 0) { |
Petr Mladek | f995b5f | 2016-03-09 15:20:59 +0100 | [diff] [blame] | 195 | pr_err("unresolvable ambiguity for symbol '%s' in object '%s'\n", |
| 196 | name, objname); |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 197 | } else if (sympos != args.count && sympos > 0) { |
| 198 | pr_err("symbol position %lu for symbol '%s' in object '%s' not found\n", |
| 199 | sympos, name, objname ? objname : "vmlinux"); |
| 200 | } else { |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 201 | *addr = args.addr; |
| 202 | return 0; |
| 203 | } |
| 204 | |
| 205 | *addr = 0; |
| 206 | return -EINVAL; |
| 207 | } |
| 208 | |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 209 | static int klp_resolve_symbols(Elf_Shdr *relasec, struct module *pmod) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 210 | { |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 211 | int i, cnt, vmlinux, ret; |
| 212 | char objname[MODULE_NAME_LEN]; |
| 213 | char symname[KSYM_NAME_LEN]; |
| 214 | char *strtab = pmod->core_kallsyms.strtab; |
| 215 | Elf_Rela *relas; |
| 216 | Elf_Sym *sym; |
| 217 | unsigned long sympos, addr; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 218 | |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 219 | /* |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 220 | * Since the field widths for objname and symname in the sscanf() |
| 221 | * call are hard-coded and correspond to MODULE_NAME_LEN and |
| 222 | * KSYM_NAME_LEN respectively, we must make sure that MODULE_NAME_LEN |
| 223 | * and KSYM_NAME_LEN have the values we expect them to have. |
| 224 | * |
| 225 | * Because the value of MODULE_NAME_LEN can differ among architectures, |
| 226 | * we use the smallest/strictest upper bound possible (56, based on |
| 227 | * the current definition of MODULE_NAME_LEN) to prevent overflows. |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 228 | */ |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 229 | BUILD_BUG_ON(MODULE_NAME_LEN < 56 || KSYM_NAME_LEN != 128); |
| 230 | |
| 231 | relas = (Elf_Rela *) relasec->sh_addr; |
| 232 | /* For each rela in this klp relocation section */ |
| 233 | for (i = 0; i < relasec->sh_size / sizeof(Elf_Rela); i++) { |
| 234 | sym = pmod->core_kallsyms.symtab + ELF_R_SYM(relas[i].r_info); |
| 235 | if (sym->st_shndx != SHN_LIVEPATCH) { |
| 236 | pr_err("symbol %s is not marked as a livepatch symbol", |
| 237 | strtab + sym->st_name); |
| 238 | return -EINVAL; |
| 239 | } |
| 240 | |
| 241 | /* Format: .klp.sym.objname.symname,sympos */ |
| 242 | cnt = sscanf(strtab + sym->st_name, |
| 243 | ".klp.sym.%55[^.].%127[^,],%lu", |
| 244 | objname, symname, &sympos); |
| 245 | if (cnt != 3) { |
| 246 | pr_err("symbol %s has an incorrectly formatted name", |
| 247 | strtab + sym->st_name); |
| 248 | return -EINVAL; |
| 249 | } |
| 250 | |
| 251 | /* klp_find_object_symbol() treats a NULL objname as vmlinux */ |
| 252 | vmlinux = !strcmp(objname, "vmlinux"); |
| 253 | ret = klp_find_object_symbol(vmlinux ? NULL : objname, |
| 254 | symname, sympos, &addr); |
| 255 | if (ret) |
| 256 | return ret; |
| 257 | |
| 258 | sym->st_value = addr; |
| 259 | } |
| 260 | |
| 261 | return 0; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 262 | } |
| 263 | |
| 264 | static int klp_write_object_relocations(struct module *pmod, |
| 265 | struct klp_object *obj) |
| 266 | { |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 267 | int i, cnt, ret = 0; |
| 268 | const char *objname, *secname; |
| 269 | char sec_objname[MODULE_NAME_LEN]; |
| 270 | Elf_Shdr *sec; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 271 | |
| 272 | if (WARN_ON(!klp_is_object_loaded(obj))) |
| 273 | return -EINVAL; |
| 274 | |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 275 | objname = klp_is_module(obj) ? obj->name : "vmlinux"; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 276 | |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 277 | /* For each klp relocation section */ |
| 278 | for (i = 1; i < pmod->klp_info->hdr.e_shnum; i++) { |
| 279 | sec = pmod->klp_info->sechdrs + i; |
| 280 | secname = pmod->klp_info->secstrings + sec->sh_name; |
| 281 | if (!(sec->sh_flags & SHF_RELA_LIVEPATCH)) |
| 282 | continue; |
Josh Poimboeuf | b56b36e | 2015-12-03 16:33:26 -0600 | [diff] [blame] | 283 | |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 284 | /* |
| 285 | * Format: .klp.rela.sec_objname.section_name |
| 286 | * See comment in klp_resolve_symbols() for an explanation |
| 287 | * of the selected field width value. |
| 288 | */ |
| 289 | cnt = sscanf(secname, ".klp.rela.%55[^.]", sec_objname); |
| 290 | if (cnt != 1) { |
| 291 | pr_err("section %s has an incorrectly formatted name", |
| 292 | secname); |
| 293 | ret = -EINVAL; |
| 294 | break; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 295 | } |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 296 | |
| 297 | if (strcmp(objname, sec_objname)) |
| 298 | continue; |
| 299 | |
| 300 | ret = klp_resolve_symbols(sec, pmod); |
| 301 | if (ret) |
| 302 | break; |
| 303 | |
| 304 | ret = apply_relocate_add(pmod->klp_info->sechdrs, |
| 305 | pmod->core_kallsyms.strtab, |
| 306 | pmod->klp_info->symndx, i, pmod); |
| 307 | if (ret) |
| 308 | break; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 309 | } |
| 310 | |
Josh Poimboeuf | b56b36e | 2015-12-03 16:33:26 -0600 | [diff] [blame] | 311 | return ret; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 312 | } |
| 313 | |
| 314 | static void notrace klp_ftrace_handler(unsigned long ip, |
| 315 | unsigned long parent_ip, |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 316 | struct ftrace_ops *fops, |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 317 | struct pt_regs *regs) |
| 318 | { |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 319 | struct klp_ops *ops; |
| 320 | struct klp_func *func; |
| 321 | |
| 322 | ops = container_of(fops, struct klp_ops, fops); |
| 323 | |
| 324 | rcu_read_lock(); |
| 325 | func = list_first_or_null_rcu(&ops->func_stack, struct klp_func, |
| 326 | stack_node); |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 327 | if (WARN_ON_ONCE(!func)) |
Petr Mladek | c4ce0da | 2015-02-18 18:02:13 +0100 | [diff] [blame] | 328 | goto unlock; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 329 | |
Li Bin | b5bfc51 | 2014-12-19 14:11:17 +0800 | [diff] [blame] | 330 | klp_arch_set_pc(regs, (unsigned long)func->new_func); |
Petr Mladek | c4ce0da | 2015-02-18 18:02:13 +0100 | [diff] [blame] | 331 | unlock: |
| 332 | rcu_read_unlock(); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 333 | } |
| 334 | |
Michael Ellerman | 28e7cbd | 2016-03-24 22:04:02 +1100 | [diff] [blame] | 335 | /* |
| 336 | * Convert a function address into the appropriate ftrace location. |
| 337 | * |
| 338 | * Usually this is just the address of the function, but on some architectures |
| 339 | * it's more complicated so allow them to provide a custom behaviour. |
| 340 | */ |
| 341 | #ifndef klp_get_ftrace_location |
| 342 | static unsigned long klp_get_ftrace_location(unsigned long faddr) |
| 343 | { |
| 344 | return faddr; |
| 345 | } |
| 346 | #endif |
| 347 | |
Josh Poimboeuf | 0937e3b | 2015-02-09 11:31:13 -0600 | [diff] [blame] | 348 | static void klp_disable_func(struct klp_func *func) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 349 | { |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 350 | struct klp_ops *ops; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 351 | |
Minfei Huang | 225f58f | 2015-07-14 11:15:37 +0800 | [diff] [blame] | 352 | if (WARN_ON(func->state != KLP_ENABLED)) |
| 353 | return; |
| 354 | if (WARN_ON(!func->old_addr)) |
| 355 | return; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 356 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 357 | ops = klp_find_ops(func->old_addr); |
| 358 | if (WARN_ON(!ops)) |
Josh Poimboeuf | 0937e3b | 2015-02-09 11:31:13 -0600 | [diff] [blame] | 359 | return; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 360 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 361 | if (list_is_singular(&ops->func_stack)) { |
Michael Ellerman | 28e7cbd | 2016-03-24 22:04:02 +1100 | [diff] [blame] | 362 | unsigned long ftrace_loc; |
| 363 | |
| 364 | ftrace_loc = klp_get_ftrace_location(func->old_addr); |
| 365 | if (WARN_ON(!ftrace_loc)) |
| 366 | return; |
| 367 | |
Josh Poimboeuf | 0937e3b | 2015-02-09 11:31:13 -0600 | [diff] [blame] | 368 | WARN_ON(unregister_ftrace_function(&ops->fops)); |
Michael Ellerman | 28e7cbd | 2016-03-24 22:04:02 +1100 | [diff] [blame] | 369 | WARN_ON(ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0)); |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 370 | |
| 371 | list_del_rcu(&func->stack_node); |
| 372 | list_del(&ops->node); |
| 373 | kfree(ops); |
| 374 | } else { |
| 375 | list_del_rcu(&func->stack_node); |
| 376 | } |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 377 | |
| 378 | func->state = KLP_DISABLED; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 379 | } |
| 380 | |
| 381 | static int klp_enable_func(struct klp_func *func) |
| 382 | { |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 383 | struct klp_ops *ops; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 384 | int ret; |
| 385 | |
| 386 | if (WARN_ON(!func->old_addr)) |
| 387 | return -EINVAL; |
| 388 | |
| 389 | if (WARN_ON(func->state != KLP_DISABLED)) |
| 390 | return -EINVAL; |
| 391 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 392 | ops = klp_find_ops(func->old_addr); |
| 393 | if (!ops) { |
Michael Ellerman | 28e7cbd | 2016-03-24 22:04:02 +1100 | [diff] [blame] | 394 | unsigned long ftrace_loc; |
| 395 | |
| 396 | ftrace_loc = klp_get_ftrace_location(func->old_addr); |
| 397 | if (!ftrace_loc) { |
| 398 | pr_err("failed to find location for function '%s'\n", |
| 399 | func->old_name); |
| 400 | return -EINVAL; |
| 401 | } |
| 402 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 403 | ops = kzalloc(sizeof(*ops), GFP_KERNEL); |
| 404 | if (!ops) |
| 405 | return -ENOMEM; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 406 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 407 | ops->fops.func = klp_ftrace_handler; |
| 408 | ops->fops.flags = FTRACE_OPS_FL_SAVE_REGS | |
| 409 | FTRACE_OPS_FL_DYNAMIC | |
| 410 | FTRACE_OPS_FL_IPMODIFY; |
| 411 | |
| 412 | list_add(&ops->node, &klp_ops); |
| 413 | |
| 414 | INIT_LIST_HEAD(&ops->func_stack); |
| 415 | list_add_rcu(&func->stack_node, &ops->func_stack); |
| 416 | |
Michael Ellerman | 28e7cbd | 2016-03-24 22:04:02 +1100 | [diff] [blame] | 417 | ret = ftrace_set_filter_ip(&ops->fops, ftrace_loc, 0, 0); |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 418 | if (ret) { |
| 419 | pr_err("failed to set ftrace filter for function '%s' (%d)\n", |
| 420 | func->old_name, ret); |
| 421 | goto err; |
| 422 | } |
| 423 | |
| 424 | ret = register_ftrace_function(&ops->fops); |
| 425 | if (ret) { |
| 426 | pr_err("failed to register ftrace handler for function '%s' (%d)\n", |
| 427 | func->old_name, ret); |
Michael Ellerman | 28e7cbd | 2016-03-24 22:04:02 +1100 | [diff] [blame] | 428 | ftrace_set_filter_ip(&ops->fops, ftrace_loc, 1, 0); |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 429 | goto err; |
| 430 | } |
| 431 | |
| 432 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 433 | } else { |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 434 | list_add_rcu(&func->stack_node, &ops->func_stack); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 435 | } |
| 436 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 437 | func->state = KLP_ENABLED; |
| 438 | |
Josh Poimboeuf | dbed7dd | 2015-01-20 16:07:55 -0600 | [diff] [blame] | 439 | return 0; |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 440 | |
| 441 | err: |
| 442 | list_del_rcu(&func->stack_node); |
| 443 | list_del(&ops->node); |
| 444 | kfree(ops); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 445 | return ret; |
| 446 | } |
| 447 | |
Josh Poimboeuf | 0937e3b | 2015-02-09 11:31:13 -0600 | [diff] [blame] | 448 | static void klp_disable_object(struct klp_object *obj) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 449 | { |
| 450 | struct klp_func *func; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 451 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 452 | klp_for_each_func(obj, func) |
Josh Poimboeuf | 0937e3b | 2015-02-09 11:31:13 -0600 | [diff] [blame] | 453 | if (func->state == KLP_ENABLED) |
| 454 | klp_disable_func(func); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 455 | |
| 456 | obj->state = KLP_DISABLED; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 457 | } |
| 458 | |
| 459 | static int klp_enable_object(struct klp_object *obj) |
| 460 | { |
| 461 | struct klp_func *func; |
| 462 | int ret; |
| 463 | |
| 464 | if (WARN_ON(obj->state != KLP_DISABLED)) |
| 465 | return -EINVAL; |
| 466 | |
| 467 | if (WARN_ON(!klp_is_object_loaded(obj))) |
| 468 | return -EINVAL; |
| 469 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 470 | klp_for_each_func(obj, func) { |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 471 | ret = klp_enable_func(func); |
Josh Poimboeuf | 0937e3b | 2015-02-09 11:31:13 -0600 | [diff] [blame] | 472 | if (ret) { |
| 473 | klp_disable_object(obj); |
| 474 | return ret; |
| 475 | } |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 476 | } |
| 477 | obj->state = KLP_ENABLED; |
| 478 | |
| 479 | return 0; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 480 | } |
| 481 | |
| 482 | static int __klp_disable_patch(struct klp_patch *patch) |
| 483 | { |
| 484 | struct klp_object *obj; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 485 | |
Josh Poimboeuf | 83a90bb | 2015-01-20 09:26:18 -0600 | [diff] [blame] | 486 | /* enforce stacking: only the last enabled patch can be disabled */ |
| 487 | if (!list_is_last(&patch->list, &klp_patches) && |
| 488 | list_next_entry(patch, list)->state == KLP_ENABLED) |
| 489 | return -EBUSY; |
| 490 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 491 | pr_notice("disabling patch '%s'\n", patch->mod->name); |
| 492 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 493 | klp_for_each_object(patch, obj) { |
Josh Poimboeuf | 0937e3b | 2015-02-09 11:31:13 -0600 | [diff] [blame] | 494 | if (obj->state == KLP_ENABLED) |
| 495 | klp_disable_object(obj); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 496 | } |
| 497 | |
| 498 | patch->state = KLP_DISABLED; |
| 499 | |
| 500 | return 0; |
| 501 | } |
| 502 | |
| 503 | /** |
| 504 | * klp_disable_patch() - disables a registered patch |
| 505 | * @patch: The registered, enabled patch to be disabled |
| 506 | * |
| 507 | * Unregisters the patched functions from ftrace. |
| 508 | * |
| 509 | * Return: 0 on success, otherwise error |
| 510 | */ |
| 511 | int klp_disable_patch(struct klp_patch *patch) |
| 512 | { |
| 513 | int ret; |
| 514 | |
| 515 | mutex_lock(&klp_mutex); |
| 516 | |
| 517 | if (!klp_is_patch_registered(patch)) { |
| 518 | ret = -EINVAL; |
| 519 | goto err; |
| 520 | } |
| 521 | |
| 522 | if (patch->state == KLP_DISABLED) { |
| 523 | ret = -EINVAL; |
| 524 | goto err; |
| 525 | } |
| 526 | |
| 527 | ret = __klp_disable_patch(patch); |
| 528 | |
| 529 | err: |
| 530 | mutex_unlock(&klp_mutex); |
| 531 | return ret; |
| 532 | } |
| 533 | EXPORT_SYMBOL_GPL(klp_disable_patch); |
| 534 | |
| 535 | static int __klp_enable_patch(struct klp_patch *patch) |
| 536 | { |
| 537 | struct klp_object *obj; |
| 538 | int ret; |
| 539 | |
| 540 | if (WARN_ON(patch->state != KLP_DISABLED)) |
| 541 | return -EINVAL; |
| 542 | |
Josh Poimboeuf | 83a90bb | 2015-01-20 09:26:18 -0600 | [diff] [blame] | 543 | /* enforce stacking: only the first disabled patch can be enabled */ |
| 544 | if (patch->list.prev != &klp_patches && |
| 545 | list_prev_entry(patch, list)->state == KLP_DISABLED) |
| 546 | return -EBUSY; |
| 547 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 548 | pr_notice("enabling patch '%s'\n", patch->mod->name); |
| 549 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 550 | klp_for_each_object(patch, obj) { |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 551 | if (!klp_is_object_loaded(obj)) |
| 552 | continue; |
| 553 | |
| 554 | ret = klp_enable_object(obj); |
| 555 | if (ret) |
| 556 | goto unregister; |
| 557 | } |
| 558 | |
| 559 | patch->state = KLP_ENABLED; |
| 560 | |
| 561 | return 0; |
| 562 | |
| 563 | unregister: |
| 564 | WARN_ON(__klp_disable_patch(patch)); |
| 565 | return ret; |
| 566 | } |
| 567 | |
| 568 | /** |
| 569 | * klp_enable_patch() - enables a registered patch |
| 570 | * @patch: The registered, disabled patch to be enabled |
| 571 | * |
| 572 | * Performs the needed symbol lookups and code relocations, |
| 573 | * then registers the patched functions with ftrace. |
| 574 | * |
| 575 | * Return: 0 on success, otherwise error |
| 576 | */ |
| 577 | int klp_enable_patch(struct klp_patch *patch) |
| 578 | { |
| 579 | int ret; |
| 580 | |
| 581 | mutex_lock(&klp_mutex); |
| 582 | |
| 583 | if (!klp_is_patch_registered(patch)) { |
| 584 | ret = -EINVAL; |
| 585 | goto err; |
| 586 | } |
| 587 | |
| 588 | ret = __klp_enable_patch(patch); |
| 589 | |
| 590 | err: |
| 591 | mutex_unlock(&klp_mutex); |
| 592 | return ret; |
| 593 | } |
| 594 | EXPORT_SYMBOL_GPL(klp_enable_patch); |
| 595 | |
| 596 | /* |
| 597 | * Sysfs Interface |
| 598 | * |
| 599 | * /sys/kernel/livepatch |
| 600 | * /sys/kernel/livepatch/<patch> |
| 601 | * /sys/kernel/livepatch/<patch>/enabled |
| 602 | * /sys/kernel/livepatch/<patch>/<object> |
Chris J Arges | 444f9e9 | 2015-12-01 20:40:56 -0600 | [diff] [blame] | 603 | * /sys/kernel/livepatch/<patch>/<object>/<function,sympos> |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 604 | */ |
| 605 | |
| 606 | static ssize_t enabled_store(struct kobject *kobj, struct kobj_attribute *attr, |
| 607 | const char *buf, size_t count) |
| 608 | { |
| 609 | struct klp_patch *patch; |
| 610 | int ret; |
| 611 | unsigned long val; |
| 612 | |
| 613 | ret = kstrtoul(buf, 10, &val); |
| 614 | if (ret) |
| 615 | return -EINVAL; |
| 616 | |
| 617 | if (val != KLP_DISABLED && val != KLP_ENABLED) |
| 618 | return -EINVAL; |
| 619 | |
| 620 | patch = container_of(kobj, struct klp_patch, kobj); |
| 621 | |
| 622 | mutex_lock(&klp_mutex); |
| 623 | |
| 624 | if (val == patch->state) { |
| 625 | /* already in requested state */ |
| 626 | ret = -EINVAL; |
| 627 | goto err; |
| 628 | } |
| 629 | |
| 630 | if (val == KLP_ENABLED) { |
| 631 | ret = __klp_enable_patch(patch); |
| 632 | if (ret) |
| 633 | goto err; |
| 634 | } else { |
| 635 | ret = __klp_disable_patch(patch); |
| 636 | if (ret) |
| 637 | goto err; |
| 638 | } |
| 639 | |
| 640 | mutex_unlock(&klp_mutex); |
| 641 | |
| 642 | return count; |
| 643 | |
| 644 | err: |
| 645 | mutex_unlock(&klp_mutex); |
| 646 | return ret; |
| 647 | } |
| 648 | |
| 649 | static ssize_t enabled_show(struct kobject *kobj, |
| 650 | struct kobj_attribute *attr, char *buf) |
| 651 | { |
| 652 | struct klp_patch *patch; |
| 653 | |
| 654 | patch = container_of(kobj, struct klp_patch, kobj); |
| 655 | return snprintf(buf, PAGE_SIZE-1, "%d\n", patch->state); |
| 656 | } |
| 657 | |
| 658 | static struct kobj_attribute enabled_kobj_attr = __ATTR_RW(enabled); |
| 659 | static struct attribute *klp_patch_attrs[] = { |
| 660 | &enabled_kobj_attr.attr, |
| 661 | NULL |
| 662 | }; |
| 663 | |
| 664 | static void klp_kobj_release_patch(struct kobject *kobj) |
| 665 | { |
| 666 | /* |
| 667 | * Once we have a consistency model we'll need to module_put() the |
| 668 | * patch module here. See klp_register_patch() for more details. |
| 669 | */ |
| 670 | } |
| 671 | |
| 672 | static struct kobj_type klp_ktype_patch = { |
| 673 | .release = klp_kobj_release_patch, |
| 674 | .sysfs_ops = &kobj_sysfs_ops, |
| 675 | .default_attrs = klp_patch_attrs, |
| 676 | }; |
| 677 | |
Miroslav Benes | cad706d | 2015-05-19 12:01:18 +0200 | [diff] [blame] | 678 | static void klp_kobj_release_object(struct kobject *kobj) |
| 679 | { |
| 680 | } |
| 681 | |
| 682 | static struct kobj_type klp_ktype_object = { |
| 683 | .release = klp_kobj_release_object, |
| 684 | .sysfs_ops = &kobj_sysfs_ops, |
| 685 | }; |
| 686 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 687 | static void klp_kobj_release_func(struct kobject *kobj) |
| 688 | { |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 689 | } |
| 690 | |
| 691 | static struct kobj_type klp_ktype_func = { |
| 692 | .release = klp_kobj_release_func, |
| 693 | .sysfs_ops = &kobj_sysfs_ops, |
| 694 | }; |
| 695 | |
| 696 | /* |
| 697 | * Free all functions' kobjects in the array up to some limit. When limit is |
| 698 | * NULL, all kobjects are freed. |
| 699 | */ |
| 700 | static void klp_free_funcs_limited(struct klp_object *obj, |
| 701 | struct klp_func *limit) |
| 702 | { |
| 703 | struct klp_func *func; |
| 704 | |
| 705 | for (func = obj->funcs; func->old_name && func != limit; func++) |
| 706 | kobject_put(&func->kobj); |
| 707 | } |
| 708 | |
| 709 | /* Clean up when a patched object is unloaded */ |
| 710 | static void klp_free_object_loaded(struct klp_object *obj) |
| 711 | { |
| 712 | struct klp_func *func; |
| 713 | |
| 714 | obj->mod = NULL; |
| 715 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 716 | klp_for_each_func(obj, func) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 717 | func->old_addr = 0; |
| 718 | } |
| 719 | |
| 720 | /* |
| 721 | * Free all objects' kobjects in the array up to some limit. When limit is |
| 722 | * NULL, all kobjects are freed. |
| 723 | */ |
| 724 | static void klp_free_objects_limited(struct klp_patch *patch, |
| 725 | struct klp_object *limit) |
| 726 | { |
| 727 | struct klp_object *obj; |
| 728 | |
| 729 | for (obj = patch->objs; obj->funcs && obj != limit; obj++) { |
| 730 | klp_free_funcs_limited(obj, NULL); |
Miroslav Benes | cad706d | 2015-05-19 12:01:18 +0200 | [diff] [blame] | 731 | kobject_put(&obj->kobj); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 732 | } |
| 733 | } |
| 734 | |
| 735 | static void klp_free_patch(struct klp_patch *patch) |
| 736 | { |
| 737 | klp_free_objects_limited(patch, NULL); |
| 738 | if (!list_empty(&patch->list)) |
| 739 | list_del(&patch->list); |
| 740 | kobject_put(&patch->kobj); |
| 741 | } |
| 742 | |
| 743 | static int klp_init_func(struct klp_object *obj, struct klp_func *func) |
| 744 | { |
Miroslav Benes | f09d908 | 2016-04-28 16:34:08 +0200 | [diff] [blame] | 745 | if (!func->old_name || !func->new_func) |
| 746 | return -EINVAL; |
| 747 | |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 748 | INIT_LIST_HEAD(&func->stack_node); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 749 | func->state = KLP_DISABLED; |
| 750 | |
Chris J Arges | 444f9e9 | 2015-12-01 20:40:56 -0600 | [diff] [blame] | 751 | /* The format for the sysfs directory is <function,sympos> where sympos |
| 752 | * is the nth occurrence of this symbol in kallsyms for the patched |
| 753 | * object. If the user selects 0 for old_sympos, then 1 will be used |
| 754 | * since a unique symbol will be the first occurrence. |
| 755 | */ |
Josh Poimboeuf | 3c33f5b | 2015-01-20 09:26:19 -0600 | [diff] [blame] | 756 | return kobject_init_and_add(&func->kobj, &klp_ktype_func, |
Chris J Arges | 444f9e9 | 2015-12-01 20:40:56 -0600 | [diff] [blame] | 757 | &obj->kobj, "%s,%lu", func->old_name, |
| 758 | func->old_sympos ? func->old_sympos : 1); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 759 | } |
| 760 | |
Jessica Yu | 255e732 | 2016-08-17 20:58:28 -0400 | [diff] [blame] | 761 | /* Arches may override this to finish any remaining arch-specific tasks */ |
| 762 | void __weak arch_klp_init_object_loaded(struct klp_patch *patch, |
| 763 | struct klp_object *obj) |
| 764 | { |
| 765 | } |
| 766 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 767 | /* parts of the initialization that is done only when the object is loaded */ |
| 768 | static int klp_init_object_loaded(struct klp_patch *patch, |
| 769 | struct klp_object *obj) |
| 770 | { |
| 771 | struct klp_func *func; |
| 772 | int ret; |
| 773 | |
Jessica Yu | 255e732 | 2016-08-17 20:58:28 -0400 | [diff] [blame] | 774 | module_disable_ro(patch->mod); |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 775 | ret = klp_write_object_relocations(patch->mod, obj); |
Jessica Yu | 255e732 | 2016-08-17 20:58:28 -0400 | [diff] [blame] | 776 | if (ret) { |
| 777 | module_enable_ro(patch->mod, true); |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 778 | return ret; |
Jessica Yu | 255e732 | 2016-08-17 20:58:28 -0400 | [diff] [blame] | 779 | } |
| 780 | |
| 781 | arch_klp_init_object_loaded(patch, obj); |
| 782 | module_enable_ro(patch->mod, true); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 783 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 784 | klp_for_each_func(obj, func) { |
Chris J Arges | b2b018e | 2015-12-01 20:40:54 -0600 | [diff] [blame] | 785 | ret = klp_find_object_symbol(obj->name, func->old_name, |
| 786 | func->old_sympos, |
| 787 | &func->old_addr); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 788 | if (ret) |
| 789 | return ret; |
| 790 | } |
| 791 | |
| 792 | return 0; |
| 793 | } |
| 794 | |
| 795 | static int klp_init_object(struct klp_patch *patch, struct klp_object *obj) |
| 796 | { |
| 797 | struct klp_func *func; |
| 798 | int ret; |
| 799 | const char *name; |
| 800 | |
| 801 | if (!obj->funcs) |
| 802 | return -EINVAL; |
| 803 | |
| 804 | obj->state = KLP_DISABLED; |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 805 | obj->mod = NULL; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 806 | |
| 807 | klp_find_object_module(obj); |
| 808 | |
| 809 | name = klp_is_module(obj) ? obj->name : "vmlinux"; |
Miroslav Benes | cad706d | 2015-05-19 12:01:18 +0200 | [diff] [blame] | 810 | ret = kobject_init_and_add(&obj->kobj, &klp_ktype_object, |
| 811 | &patch->kobj, "%s", name); |
| 812 | if (ret) |
| 813 | return ret; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 814 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 815 | klp_for_each_func(obj, func) { |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 816 | ret = klp_init_func(obj, func); |
| 817 | if (ret) |
| 818 | goto free; |
| 819 | } |
| 820 | |
| 821 | if (klp_is_object_loaded(obj)) { |
| 822 | ret = klp_init_object_loaded(patch, obj); |
| 823 | if (ret) |
| 824 | goto free; |
| 825 | } |
| 826 | |
| 827 | return 0; |
| 828 | |
| 829 | free: |
| 830 | klp_free_funcs_limited(obj, func); |
Miroslav Benes | cad706d | 2015-05-19 12:01:18 +0200 | [diff] [blame] | 831 | kobject_put(&obj->kobj); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 832 | return ret; |
| 833 | } |
| 834 | |
| 835 | static int klp_init_patch(struct klp_patch *patch) |
| 836 | { |
| 837 | struct klp_object *obj; |
| 838 | int ret; |
| 839 | |
| 840 | if (!patch->objs) |
| 841 | return -EINVAL; |
| 842 | |
| 843 | mutex_lock(&klp_mutex); |
| 844 | |
| 845 | patch->state = KLP_DISABLED; |
| 846 | |
| 847 | ret = kobject_init_and_add(&patch->kobj, &klp_ktype_patch, |
Jiri Kosina | e0b561e | 2015-02-15 10:03:20 +0100 | [diff] [blame] | 848 | klp_root_kobj, "%s", patch->mod->name); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 849 | if (ret) |
| 850 | goto unlock; |
| 851 | |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 852 | klp_for_each_object(patch, obj) { |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 853 | ret = klp_init_object(patch, obj); |
| 854 | if (ret) |
| 855 | goto free; |
| 856 | } |
| 857 | |
Josh Poimboeuf | 99590ba | 2015-01-09 14:03:04 -0600 | [diff] [blame] | 858 | list_add_tail(&patch->list, &klp_patches); |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 859 | |
| 860 | mutex_unlock(&klp_mutex); |
| 861 | |
| 862 | return 0; |
| 863 | |
| 864 | free: |
| 865 | klp_free_objects_limited(patch, obj); |
| 866 | kobject_put(&patch->kobj); |
| 867 | unlock: |
| 868 | mutex_unlock(&klp_mutex); |
| 869 | return ret; |
| 870 | } |
| 871 | |
| 872 | /** |
| 873 | * klp_unregister_patch() - unregisters a patch |
| 874 | * @patch: Disabled patch to be unregistered |
| 875 | * |
| 876 | * Frees the data structures and removes the sysfs interface. |
| 877 | * |
| 878 | * Return: 0 on success, otherwise error |
| 879 | */ |
| 880 | int klp_unregister_patch(struct klp_patch *patch) |
| 881 | { |
| 882 | int ret = 0; |
| 883 | |
| 884 | mutex_lock(&klp_mutex); |
| 885 | |
| 886 | if (!klp_is_patch_registered(patch)) { |
| 887 | ret = -EINVAL; |
| 888 | goto out; |
| 889 | } |
| 890 | |
| 891 | if (patch->state == KLP_ENABLED) { |
| 892 | ret = -EBUSY; |
| 893 | goto out; |
| 894 | } |
| 895 | |
| 896 | klp_free_patch(patch); |
| 897 | |
| 898 | out: |
| 899 | mutex_unlock(&klp_mutex); |
| 900 | return ret; |
| 901 | } |
| 902 | EXPORT_SYMBOL_GPL(klp_unregister_patch); |
| 903 | |
| 904 | /** |
| 905 | * klp_register_patch() - registers a patch |
| 906 | * @patch: Patch to be registered |
| 907 | * |
| 908 | * Initializes the data structure associated with the patch and |
| 909 | * creates the sysfs interface. |
| 910 | * |
| 911 | * Return: 0 on success, otherwise error |
| 912 | */ |
| 913 | int klp_register_patch(struct klp_patch *patch) |
| 914 | { |
| 915 | int ret; |
| 916 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 917 | if (!patch || !patch->mod) |
| 918 | return -EINVAL; |
| 919 | |
Jessica Yu | 425595a | 2016-03-22 20:03:18 -0400 | [diff] [blame] | 920 | if (!is_livepatch_module(patch->mod)) { |
| 921 | pr_err("module %s is not marked as a livepatch module", |
| 922 | patch->mod->name); |
| 923 | return -EINVAL; |
| 924 | } |
| 925 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 926 | if (!klp_initialized()) |
| 927 | return -ENODEV; |
| 928 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 929 | /* |
| 930 | * A reference is taken on the patch module to prevent it from being |
| 931 | * unloaded. Right now, we don't allow patch modules to unload since |
| 932 | * there is currently no method to determine if a thread is still |
| 933 | * running in the patched code contained in the patch module once |
| 934 | * the ftrace registration is successful. |
| 935 | */ |
| 936 | if (!try_module_get(patch->mod)) |
| 937 | return -ENODEV; |
| 938 | |
| 939 | ret = klp_init_patch(patch); |
| 940 | if (ret) |
| 941 | module_put(patch->mod); |
| 942 | |
| 943 | return ret; |
| 944 | } |
| 945 | EXPORT_SYMBOL_GPL(klp_register_patch); |
| 946 | |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 947 | int klp_module_coming(struct module *mod) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 948 | { |
Minfei Huang | 36e505c | 2015-05-15 10:22:48 +0800 | [diff] [blame] | 949 | int ret; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 950 | struct klp_patch *patch; |
| 951 | struct klp_object *obj; |
| 952 | |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 953 | if (WARN_ON(mod->state != MODULE_STATE_COMING)) |
| 954 | return -EINVAL; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 955 | |
| 956 | mutex_lock(&klp_mutex); |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 957 | /* |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 958 | * Each module has to know that klp_module_coming() |
| 959 | * has been called. We never know what module will |
| 960 | * get patched by a new patch. |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 961 | */ |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 962 | mod->klp_alive = true; |
Petr Mladek | 8cb2c2d | 2015-03-12 12:55:13 +0100 | [diff] [blame] | 963 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 964 | list_for_each_entry(patch, &klp_patches, list) { |
Jiri Slaby | 8cdd043 | 2015-05-19 12:01:19 +0200 | [diff] [blame] | 965 | klp_for_each_object(patch, obj) { |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 966 | if (!klp_is_module(obj) || strcmp(obj->name, mod->name)) |
| 967 | continue; |
| 968 | |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 969 | obj->mod = mod; |
| 970 | |
| 971 | ret = klp_init_object_loaded(patch, obj); |
| 972 | if (ret) { |
| 973 | pr_warn("failed to initialize patch '%s' for module '%s' (%d)\n", |
| 974 | patch->mod->name, obj->mod->name, ret); |
| 975 | goto err; |
| 976 | } |
| 977 | |
| 978 | if (patch->state == KLP_DISABLED) |
| 979 | break; |
| 980 | |
| 981 | pr_notice("applying patch '%s' to loading module '%s'\n", |
| 982 | patch->mod->name, obj->mod->name); |
| 983 | |
| 984 | ret = klp_enable_object(obj); |
| 985 | if (ret) { |
| 986 | pr_warn("failed to apply patch '%s' to module '%s' (%d)\n", |
| 987 | patch->mod->name, obj->mod->name, ret); |
| 988 | goto err; |
| 989 | } |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 990 | |
| 991 | break; |
| 992 | } |
| 993 | } |
| 994 | |
| 995 | mutex_unlock(&klp_mutex); |
| 996 | |
| 997 | return 0; |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 998 | |
| 999 | err: |
| 1000 | /* |
| 1001 | * If a patch is unsuccessfully applied, return |
| 1002 | * error to the module loader. |
| 1003 | */ |
| 1004 | pr_warn("patch '%s' failed for module '%s', refusing to load module '%s'\n", |
| 1005 | patch->mod->name, obj->mod->name, obj->mod->name); |
| 1006 | mod->klp_alive = false; |
| 1007 | klp_free_object_loaded(obj); |
| 1008 | mutex_unlock(&klp_mutex); |
| 1009 | |
| 1010 | return ret; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 1011 | } |
| 1012 | |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 1013 | void klp_module_going(struct module *mod) |
| 1014 | { |
| 1015 | struct klp_patch *patch; |
| 1016 | struct klp_object *obj; |
| 1017 | |
| 1018 | if (WARN_ON(mod->state != MODULE_STATE_GOING && |
| 1019 | mod->state != MODULE_STATE_COMING)) |
| 1020 | return; |
| 1021 | |
| 1022 | mutex_lock(&klp_mutex); |
| 1023 | /* |
| 1024 | * Each module has to know that klp_module_going() |
| 1025 | * has been called. We never know what module will |
| 1026 | * get patched by a new patch. |
| 1027 | */ |
| 1028 | mod->klp_alive = false; |
| 1029 | |
| 1030 | list_for_each_entry(patch, &klp_patches, list) { |
| 1031 | klp_for_each_object(patch, obj) { |
| 1032 | if (!klp_is_module(obj) || strcmp(obj->name, mod->name)) |
| 1033 | continue; |
| 1034 | |
| 1035 | if (patch->state != KLP_DISABLED) { |
| 1036 | pr_notice("reverting patch '%s' on unloading module '%s'\n", |
| 1037 | patch->mod->name, obj->mod->name); |
| 1038 | klp_disable_object(obj); |
| 1039 | } |
| 1040 | |
| 1041 | klp_free_object_loaded(obj); |
| 1042 | break; |
| 1043 | } |
| 1044 | } |
| 1045 | |
| 1046 | mutex_unlock(&klp_mutex); |
| 1047 | } |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 1048 | |
Minfei Huang | 26029d8 | 2015-05-22 22:26:29 +0800 | [diff] [blame] | 1049 | static int __init klp_init(void) |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 1050 | { |
| 1051 | int ret; |
| 1052 | |
Jiri Kosina | b9dfe0b | 2015-01-09 10:53:21 +0100 | [diff] [blame] | 1053 | ret = klp_check_compiler_support(); |
| 1054 | if (ret) { |
| 1055 | pr_info("Your compiler is too old; turning off.\n"); |
| 1056 | return -EINVAL; |
| 1057 | } |
| 1058 | |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 1059 | klp_root_kobj = kobject_create_and_add("livepatch", kernel_kobj); |
Jessica Yu | 7e545d6 | 2016-03-16 20:55:39 -0400 | [diff] [blame] | 1060 | if (!klp_root_kobj) |
| 1061 | return -ENOMEM; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 1062 | |
| 1063 | return 0; |
Seth Jennings | b700e7f | 2014-12-16 11:58:19 -0600 | [diff] [blame] | 1064 | } |
| 1065 | |
| 1066 | module_init(klp_init); |