blob: b052e883dd8cc35df741a4e18c5236e38a234936 [file] [log] [blame]
Amerigo Wang2d5bf282009-06-03 21:46:09 -04001/* Kernel module help for x86.
2 Copyright (C) 2001 Rusty Russell.
3
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17*/
Joe Perchesc767a542012-05-21 19:50:07 -070018
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
Amerigo Wang2d5bf282009-06-03 21:46:09 -040021#include <linux/moduleloader.h>
22#include <linux/elf.h>
23#include <linux/vmalloc.h>
24#include <linux/fs.h>
25#include <linux/string.h>
26#include <linux/kernel.h>
Andrey Ryabininbebf56a2015-02-13 14:40:17 -080027#include <linux/kasan.h>
Amerigo Wang2d5bf282009-06-03 21:46:09 -040028#include <linux/bug.h>
29#include <linux/mm.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090030#include <linux/gfp.h>
Jason Barond430d3d2011-03-16 17:29:47 -040031#include <linux/jump_label.h>
Kees Cooke2b32e62014-02-25 16:59:17 -080032#include <linux/random.h>
Amerigo Wang2d5bf282009-06-03 21:46:09 -040033
Andy Lutomirski35de5b02016-04-26 12:23:24 -070034#include <asm/text-patching.h>
Amerigo Wang2d5bf282009-06-03 21:46:09 -040035#include <asm/page.h>
36#include <asm/pgtable.h>
Borislav Petkov78cac482015-04-01 12:49:52 +020037#include <asm/setup.h>
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -050038#include <asm/unwind.h>
Amerigo Wang2d5bf282009-06-03 21:46:09 -040039
40#if 0
Joe Perchesc767a542012-05-21 19:50:07 -070041#define DEBUGP(fmt, ...) \
42 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
Amerigo Wang2d5bf282009-06-03 21:46:09 -040043#else
Joe Perchesc767a542012-05-21 19:50:07 -070044#define DEBUGP(fmt, ...) \
45do { \
46 if (0) \
47 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
48} while (0)
Amerigo Wang2d5bf282009-06-03 21:46:09 -040049#endif
50
Kees Cooke2b32e62014-02-25 16:59:17 -080051#ifdef CONFIG_RANDOMIZE_BASE
52static unsigned long module_load_offset;
Kees Cooke2b32e62014-02-25 16:59:17 -080053
Kees Cook9dd721c2014-03-10 13:42:48 -070054/* Mutex protects the module_load_offset. */
55static DEFINE_MUTEX(module_kaslr_mutex);
56
Kees Cooke2b32e62014-02-25 16:59:17 -080057static unsigned long int get_module_load_offset(void)
58{
Borislav Petkov78cac482015-04-01 12:49:52 +020059 if (kaslr_enabled()) {
Kees Cook9dd721c2014-03-10 13:42:48 -070060 mutex_lock(&module_kaslr_mutex);
Kees Cooke2b32e62014-02-25 16:59:17 -080061 /*
62 * Calculate the module_load_offset the first time this
63 * code is called. Once calculated it stays the same until
64 * reboot.
65 */
66 if (module_load_offset == 0)
67 module_load_offset =
68 (get_random_int() % 1024 + 1) * PAGE_SIZE;
Kees Cook9dd721c2014-03-10 13:42:48 -070069 mutex_unlock(&module_kaslr_mutex);
Kees Cooke2b32e62014-02-25 16:59:17 -080070 }
71 return module_load_offset;
72}
73#else
74static unsigned long int get_module_load_offset(void)
75{
76 return 0;
77}
78#endif
79
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040080void *module_alloc(unsigned long size)
81{
Andrey Ryabininbebf56a2015-02-13 14:40:17 -080082 void *p;
83
David Rientjesd0a21262011-01-13 15:46:02 -080084 if (PAGE_ALIGN(size) > MODULES_LEN)
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040085 return NULL;
Andrey Ryabininbebf56a2015-02-13 14:40:17 -080086
87 p = __vmalloc_node_range(size, MODULE_ALIGN,
Kees Cooke2b32e62014-02-25 16:59:17 -080088 MODULES_VADDR + get_module_load_offset(),
Michal Hocko19809c22017-05-08 15:57:44 -070089 MODULES_END, GFP_KERNEL,
Andrey Ryabinincb9e3c22015-02-13 14:40:07 -080090 PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
Kees Cooke2b32e62014-02-25 16:59:17 -080091 __builtin_return_address(0));
Andrey Ryabininbebf56a2015-02-13 14:40:17 -080092 if (p && (kasan_module_alloc(p, size) < 0)) {
93 vfree(p);
94 return NULL;
95 }
96
97 return p;
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040098}
Amerigo Wang0fdc83b2009-06-03 21:46:19 -040099
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400100#ifdef CONFIG_X86_32
101int apply_relocate(Elf32_Shdr *sechdrs,
102 const char *strtab,
103 unsigned int symindex,
104 unsigned int relsec,
105 struct module *me)
106{
107 unsigned int i;
108 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
109 Elf32_Sym *sym;
110 uint32_t *location;
111
Joe Perchesc767a542012-05-21 19:50:07 -0700112 DEBUGP("Applying relocate section %u to %u\n",
113 relsec, sechdrs[relsec].sh_info);
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400114 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
115 /* This is where to make the change */
116 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
117 + rel[i].r_offset;
118 /* This is the symbol it is referring to. Note that all
119 undefined symbols have been resolved. */
120 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
121 + ELF32_R_SYM(rel[i].r_info);
122
123 switch (ELF32_R_TYPE(rel[i].r_info)) {
124 case R_386_32:
125 /* We add the value into the location given */
126 *location += sym->st_value;
127 break;
128 case R_386_PC32:
Geert Uytterhoeven2e76c282012-07-19 22:29:11 +0200129 /* Add the value, subtract its position */
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400130 *location += sym->st_value - (uint32_t)location;
131 break;
132 default:
Joe Perchesc767a542012-05-21 19:50:07 -0700133 pr_err("%s: Unknown relocation: %u\n",
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400134 me->name, ELF32_R_TYPE(rel[i].r_info));
135 return -ENOEXEC;
136 }
137 }
138 return 0;
139}
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400140#else /*X86_64*/
141int apply_relocate_add(Elf64_Shdr *sechdrs,
142 const char *strtab,
143 unsigned int symindex,
144 unsigned int relsec,
145 struct module *me)
146{
147 unsigned int i;
148 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
149 Elf64_Sym *sym;
150 void *loc;
151 u64 val;
152
Joe Perchesc767a542012-05-21 19:50:07 -0700153 DEBUGP("Applying relocate section %u to %u\n",
154 relsec, sechdrs[relsec].sh_info);
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400155 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
156 /* This is where to make the change */
157 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
158 + rel[i].r_offset;
159
160 /* This is the symbol it is referring to. Note that all
161 undefined symbols have been resolved. */
162 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
163 + ELF64_R_SYM(rel[i].r_info);
164
165 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
Joe Perchesc767a542012-05-21 19:50:07 -0700166 (int)ELF64_R_TYPE(rel[i].r_info),
167 sym->st_value, rel[i].r_addend, (u64)loc);
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400168
169 val = sym->st_value + rel[i].r_addend;
170
171 switch (ELF64_R_TYPE(rel[i].r_info)) {
172 case R_X86_64_NONE:
173 break;
174 case R_X86_64_64:
Josh Poimboeufeda9cec2017-11-03 07:58:54 -0500175 if (*(u64 *)loc != 0)
176 goto invalid_relocation;
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400177 *(u64 *)loc = val;
178 break;
179 case R_X86_64_32:
Josh Poimboeufeda9cec2017-11-03 07:58:54 -0500180 if (*(u32 *)loc != 0)
181 goto invalid_relocation;
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400182 *(u32 *)loc = val;
183 if (val != *(u32 *)loc)
184 goto overflow;
185 break;
186 case R_X86_64_32S:
Josh Poimboeufeda9cec2017-11-03 07:58:54 -0500187 if (*(s32 *)loc != 0)
188 goto invalid_relocation;
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400189 *(s32 *)loc = val;
190 if ((s64)val != *(s32 *)loc)
191 goto overflow;
192 break;
193 case R_X86_64_PC32:
H.J. Lub21ebf2f2018-02-07 14:20:09 -0800194 case R_X86_64_PLT32:
Josh Poimboeufeda9cec2017-11-03 07:58:54 -0500195 if (*(u32 *)loc != 0)
196 goto invalid_relocation;
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400197 val -= (u64)loc;
198 *(u32 *)loc = val;
199#if 0
200 if ((s64)val != *(s32 *)loc)
201 goto overflow;
202#endif
203 break;
Ard Biesheuvelb40a1422018-09-18 23:51:39 -0700204 case R_X86_64_PC64:
205 if (*(u64 *)loc != 0)
206 goto invalid_relocation;
207 val -= (u64)loc;
208 *(u64 *)loc = val;
209 break;
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400210 default:
Joe Perchesc767a542012-05-21 19:50:07 -0700211 pr_err("%s: Unknown rela relocation: %llu\n",
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400212 me->name, ELF64_R_TYPE(rel[i].r_info));
213 return -ENOEXEC;
214 }
215 }
216 return 0;
217
Josh Poimboeufeda9cec2017-11-03 07:58:54 -0500218invalid_relocation:
219 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
220 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
221 return -ENOEXEC;
222
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400223overflow:
Joe Perchesc767a542012-05-21 19:50:07 -0700224 pr_err("overflow in relocation type %d val %Lx\n",
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400225 (int)ELF64_R_TYPE(rel[i].r_info), val);
Joe Perchesc767a542012-05-21 19:50:07 -0700226 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400227 me->name);
228 return -ENOEXEC;
229}
Amerigo Wang0fdc83b2009-06-03 21:46:19 -0400230#endif
231
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400232int module_finalize(const Elf_Ehdr *hdr,
233 const Elf_Shdr *sechdrs,
234 struct module *me)
235{
236 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500237 *para = NULL, *orc = NULL, *orc_ip = NULL;
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400238 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
239
240 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
241 if (!strcmp(".text", secstrings + s->sh_name))
242 text = s;
243 if (!strcmp(".altinstructions", secstrings + s->sh_name))
244 alt = s;
245 if (!strcmp(".smp_locks", secstrings + s->sh_name))
246 locks = s;
247 if (!strcmp(".parainstructions", secstrings + s->sh_name))
248 para = s;
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500249 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
250 orc = s;
251 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
252 orc_ip = s;
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400253 }
254
255 if (alt) {
256 /* patch .altinstructions */
257 void *aseg = (void *)alt->sh_addr;
258 apply_alternatives(aseg, aseg + alt->sh_size);
259 }
260 if (locks && text) {
261 void *lseg = (void *)locks->sh_addr;
262 void *tseg = (void *)text->sh_addr;
263 alternatives_smp_module_add(me, me->name,
264 lseg, lseg + locks->sh_size,
265 tseg, tseg + text->sh_size);
266 }
267
268 if (para) {
269 void *pseg = (void *)para->sh_addr;
270 apply_paravirt(pseg, pseg + para->sh_size);
271 }
272
Jason Barond9f5ab72010-09-17 11:09:22 -0400273 /* make jump label nops */
274 jump_label_apply_nops(me);
275
Josh Poimboeufee9f8fc2017-07-24 18:36:57 -0500276 if (orc && orc_ip)
277 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
278 (void *)orc->sh_addr, orc->sh_size);
279
Linus Torvalds53363772010-10-05 11:29:27 -0700280 return 0;
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400281}
282
283void module_arch_cleanup(struct module *mod)
284{
285 alternatives_smp_module_del(mod);
Amerigo Wang2d5bf282009-06-03 21:46:09 -0400286}