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6
7#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
8
9#include <linux/moduleloader.h>
10#include <linux/elf.h>
11#include <linux/vmalloc.h>
12#include <linux/fs.h>
13#include <linux/string.h>
14#include <linux/kernel.h>
15#include <linux/kasan.h>
16#include <linux/bug.h>
17#include <linux/mm.h>
18#include <linux/gfp.h>
19#include <linux/jump_label.h>
20#include <linux/random.h>
21
22#include <asm/text-patching.h>
23#include <asm/page.h>
24#include <asm/pgtable.h>
25#include <asm/setup.h>
26#include <asm/unwind.h>
27
28#if 0
29#define DEBUGP(fmt, ...) \
30 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
31#else
32#define DEBUGP(fmt, ...) \
33do { \
34 if (0) \
35 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
36} while (0)
37#endif
38
39#ifdef CONFIG_RANDOMIZE_BASE
40static unsigned long module_load_offset;
41
42
43static DEFINE_MUTEX(module_kaslr_mutex);
44
45static unsigned long int get_module_load_offset(void)
46{
47 if (kaslr_enabled()) {
48 mutex_lock(&module_kaslr_mutex);
49
50
51
52
53
54 if (module_load_offset == 0)
55 module_load_offset =
56 (get_random_int() % 1024 + 1) * PAGE_SIZE;
57 mutex_unlock(&module_kaslr_mutex);
58 }
59 return module_load_offset;
60}
61#else
62static unsigned long int get_module_load_offset(void)
63{
64 return 0;
65}
66#endif
67
68void *module_alloc(unsigned long size)
69{
70 void *p;
71
72 if (PAGE_ALIGN(size) > MODULES_LEN)
73 return NULL;
74
75 p = __vmalloc_node_range(size, MODULE_ALIGN,
76 MODULES_VADDR + get_module_load_offset(),
77 MODULES_END, GFP_KERNEL,
78 PAGE_KERNEL, 0, NUMA_NO_NODE,
79 __builtin_return_address(0));
80 if (p && (kasan_module_alloc(p, size) < 0)) {
81 vfree(p);
82 return NULL;
83 }
84
85 return p;
86}
87
88#ifdef CONFIG_X86_32
89int apply_relocate(Elf32_Shdr *sechdrs,
90 const char *strtab,
91 unsigned int symindex,
92 unsigned int relsec,
93 struct module *me)
94{
95 unsigned int i;
96 Elf32_Rel *rel = (void *)sechdrs[relsec].sh_addr;
97 Elf32_Sym *sym;
98 uint32_t *location;
99
100 DEBUGP("Applying relocate section %u to %u\n",
101 relsec, sechdrs[relsec].sh_info);
102 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
103
104 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
105 + rel[i].r_offset;
106
107
108 sym = (Elf32_Sym *)sechdrs[symindex].sh_addr
109 + ELF32_R_SYM(rel[i].r_info);
110
111 switch (ELF32_R_TYPE(rel[i].r_info)) {
112 case R_386_32:
113
114 *location += sym->st_value;
115 break;
116 case R_386_PC32:
117
118 *location += sym->st_value - (uint32_t)location;
119 break;
120 default:
121 pr_err("%s: Unknown relocation: %u\n",
122 me->name, ELF32_R_TYPE(rel[i].r_info));
123 return -ENOEXEC;
124 }
125 }
126 return 0;
127}
128#else
129int apply_relocate_add(Elf64_Shdr *sechdrs,
130 const char *strtab,
131 unsigned int symindex,
132 unsigned int relsec,
133 struct module *me)
134{
135 unsigned int i;
136 Elf64_Rela *rel = (void *)sechdrs[relsec].sh_addr;
137 Elf64_Sym *sym;
138 void *loc;
139 u64 val;
140
141 DEBUGP("Applying relocate section %u to %u\n",
142 relsec, sechdrs[relsec].sh_info);
143 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
144
145 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
146 + rel[i].r_offset;
147
148
149
150 sym = (Elf64_Sym *)sechdrs[symindex].sh_addr
151 + ELF64_R_SYM(rel[i].r_info);
152
153 DEBUGP("type %d st_value %Lx r_addend %Lx loc %Lx\n",
154 (int)ELF64_R_TYPE(rel[i].r_info),
155 sym->st_value, rel[i].r_addend, (u64)loc);
156
157 val = sym->st_value + rel[i].r_addend;
158
159 switch (ELF64_R_TYPE(rel[i].r_info)) {
160 case R_X86_64_NONE:
161 break;
162 case R_X86_64_64:
163 if (*(u64 *)loc != 0)
164 goto invalid_relocation;
165 *(u64 *)loc = val;
166 break;
167 case R_X86_64_32:
168 if (*(u32 *)loc != 0)
169 goto invalid_relocation;
170 *(u32 *)loc = val;
171 if (val != *(u32 *)loc)
172 goto overflow;
173 break;
174 case R_X86_64_32S:
175 if (*(s32 *)loc != 0)
176 goto invalid_relocation;
177 *(s32 *)loc = val;
178 if ((s64)val != *(s32 *)loc)
179 goto overflow;
180 break;
181 case R_X86_64_PC32:
182 case R_X86_64_PLT32:
183 if (*(u32 *)loc != 0)
184 goto invalid_relocation;
185 val -= (u64)loc;
186 *(u32 *)loc = val;
187#if 0
188 if ((s64)val != *(s32 *)loc)
189 goto overflow;
190#endif
191 break;
192 case R_X86_64_PC64:
193 if (*(u64 *)loc != 0)
194 goto invalid_relocation;
195 val -= (u64)loc;
196 *(u64 *)loc = val;
197 break;
198 default:
199 pr_err("%s: Unknown rela relocation: %llu\n",
200 me->name, ELF64_R_TYPE(rel[i].r_info));
201 return -ENOEXEC;
202 }
203 }
204 return 0;
205
206invalid_relocation:
207 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
208 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
209 return -ENOEXEC;
210
211overflow:
212 pr_err("overflow in relocation type %d val %Lx\n",
213 (int)ELF64_R_TYPE(rel[i].r_info), val);
214 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
215 me->name);
216 return -ENOEXEC;
217}
218#endif
219
220int module_finalize(const Elf_Ehdr *hdr,
221 const Elf_Shdr *sechdrs,
222 struct module *me)
223{
224 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
225 *para = NULL, *orc = NULL, *orc_ip = NULL;
226 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
227
228 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
229 if (!strcmp(".text", secstrings + s->sh_name))
230 text = s;
231 if (!strcmp(".altinstructions", secstrings + s->sh_name))
232 alt = s;
233 if (!strcmp(".smp_locks", secstrings + s->sh_name))
234 locks = s;
235 if (!strcmp(".parainstructions", secstrings + s->sh_name))
236 para = s;
237 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
238 orc = s;
239 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
240 orc_ip = s;
241 }
242
243 if (alt) {
244
245 void *aseg = (void *)alt->sh_addr;
246 apply_alternatives(aseg, aseg + alt->sh_size);
247 }
248 if (locks && text) {
249 void *lseg = (void *)locks->sh_addr;
250 void *tseg = (void *)text->sh_addr;
251 alternatives_smp_module_add(me, me->name,
252 lseg, lseg + locks->sh_size,
253 tseg, tseg + text->sh_size);
254 }
255
256 if (para) {
257 void *pseg = (void *)para->sh_addr;
258 apply_paravirt(pseg, pseg + para->sh_size);
259 }
260
261
262 jump_label_apply_nops(me);
263
264 if (orc && orc_ip)
265 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
266 (void *)orc->sh_addr, orc->sh_size);
267
268 return 0;
269}
270
271void module_arch_cleanup(struct module *mod)
272{
273 alternatives_smp_module_del(mod);
274}
275
