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19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#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>
27#include <linux/kasan.h>
28#include <linux/bug.h>
29#include <linux/mm.h>
30#include <linux/gfp.h>
31#include <linux/jump_label.h>
32#include <linux/random.h>
33
34#include <asm/text-patching.h>
35#include <asm/page.h>
36#include <asm/pgtable.h>
37#include <asm/setup.h>
38#include <asm/unwind.h>
39
40#if 0
41#define DEBUGP(fmt, ...) \
42 printk(KERN_DEBUG fmt, ##__VA_ARGS__)
43#else
44#define DEBUGP(fmt, ...) \
45do { \
46 if (0) \
47 printk(KERN_DEBUG fmt, ##__VA_ARGS__); \
48} while (0)
49#endif
50
51#ifdef CONFIG_RANDOMIZE_BASE
52static unsigned long module_load_offset;
53
54
55static DEFINE_MUTEX(module_kaslr_mutex);
56
57static unsigned long int get_module_load_offset(void)
58{
59 if (kaslr_enabled()) {
60 mutex_lock(&module_kaslr_mutex);
61
62
63
64
65
66 if (module_load_offset == 0)
67 module_load_offset =
68 (get_random_int() % 1024 + 1) * PAGE_SIZE;
69 mutex_unlock(&module_kaslr_mutex);
70 }
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
80void *module_alloc(unsigned long size)
81{
82 void *p;
83
84 if (PAGE_ALIGN(size) > MODULES_LEN)
85 return NULL;
86
87 p = __vmalloc_node_range(size, MODULE_ALIGN,
88 MODULES_VADDR + get_module_load_offset(),
89 MODULES_END, GFP_KERNEL,
90 PAGE_KERNEL_EXEC, 0, NUMA_NO_NODE,
91 __builtin_return_address(0));
92 if (p && (kasan_module_alloc(p, size) < 0)) {
93 vfree(p);
94 return NULL;
95 }
96
97 return p;
98}
99
100#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
112 DEBUGP("Applying relocate section %u to %u\n",
113 relsec, sechdrs[relsec].sh_info);
114 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
115
116 location = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
117 + rel[i].r_offset;
118
119
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
126 *location += sym->st_value;
127 break;
128 case R_386_PC32:
129
130 *location += sym->st_value - (uint32_t)location;
131 break;
132 default:
133 pr_err("%s: Unknown relocation: %u\n",
134 me->name, ELF32_R_TYPE(rel[i].r_info));
135 return -ENOEXEC;
136 }
137 }
138 return 0;
139}
140#else
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
153 DEBUGP("Applying relocate section %u to %u\n",
154 relsec, sechdrs[relsec].sh_info);
155 for (i = 0; i < sechdrs[relsec].sh_size / sizeof(*rel); i++) {
156
157 loc = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr
158 + rel[i].r_offset;
159
160
161
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",
166 (int)ELF64_R_TYPE(rel[i].r_info),
167 sym->st_value, rel[i].r_addend, (u64)loc);
168
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:
175 if (*(u64 *)loc != 0)
176 goto invalid_relocation;
177 *(u64 *)loc = val;
178 break;
179 case R_X86_64_32:
180 if (*(u32 *)loc != 0)
181 goto invalid_relocation;
182 *(u32 *)loc = val;
183 if (val != *(u32 *)loc)
184 goto overflow;
185 break;
186 case R_X86_64_32S:
187 if (*(s32 *)loc != 0)
188 goto invalid_relocation;
189 *(s32 *)loc = val;
190 if ((s64)val != *(s32 *)loc)
191 goto overflow;
192 break;
193 case R_X86_64_PC32:
194 case R_X86_64_PLT32:
195 if (*(u32 *)loc != 0)
196 goto invalid_relocation;
197 val -= (u64)loc;
198 *(u32 *)loc = val;
199#if 0
200 if ((s64)val != *(s32 *)loc)
201 goto overflow;
202#endif
203 break;
204 default:
205 pr_err("%s: Unknown rela relocation: %llu\n",
206 me->name, ELF64_R_TYPE(rel[i].r_info));
207 return -ENOEXEC;
208 }
209 }
210 return 0;
211
212invalid_relocation:
213 pr_err("x86/modules: Skipping invalid relocation target, existing value is nonzero for type %d, loc %p, val %Lx\n",
214 (int)ELF64_R_TYPE(rel[i].r_info), loc, val);
215 return -ENOEXEC;
216
217overflow:
218 pr_err("overflow in relocation type %d val %Lx\n",
219 (int)ELF64_R_TYPE(rel[i].r_info), val);
220 pr_err("`%s' likely not compiled with -mcmodel=kernel\n",
221 me->name);
222 return -ENOEXEC;
223}
224#endif
225
226int module_finalize(const Elf_Ehdr *hdr,
227 const Elf_Shdr *sechdrs,
228 struct module *me)
229{
230 const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL,
231 *para = NULL, *orc = NULL, *orc_ip = NULL;
232 char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
233
234 for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
235 if (!strcmp(".text", secstrings + s->sh_name))
236 text = s;
237 if (!strcmp(".altinstructions", secstrings + s->sh_name))
238 alt = s;
239 if (!strcmp(".smp_locks", secstrings + s->sh_name))
240 locks = s;
241 if (!strcmp(".parainstructions", secstrings + s->sh_name))
242 para = s;
243 if (!strcmp(".orc_unwind", secstrings + s->sh_name))
244 orc = s;
245 if (!strcmp(".orc_unwind_ip", secstrings + s->sh_name))
246 orc_ip = s;
247 }
248
249 if (alt) {
250
251 void *aseg = (void *)alt->sh_addr;
252 apply_alternatives(aseg, aseg + alt->sh_size);
253 }
254 if (locks && text) {
255 void *lseg = (void *)locks->sh_addr;
256 void *tseg = (void *)text->sh_addr;
257 alternatives_smp_module_add(me, me->name,
258 lseg, lseg + locks->sh_size,
259 tseg, tseg + text->sh_size);
260 }
261
262 if (para) {
263 void *pseg = (void *)para->sh_addr;
264 apply_paravirt(pseg, pseg + para->sh_size);
265 }
266
267
268 jump_label_apply_nops(me);
269
270 if (orc && orc_ip)
271 unwind_module_init(me, (void *)orc_ip->sh_addr, orc_ip->sh_size,
272 (void *)orc->sh_addr, orc->sh_size);
273
274 return 0;
275}
276
277void module_arch_cleanup(struct module *mod)
278{
279 alternatives_smp_module_del(mod);
280}
281
