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e886bf9d | 1 | // SPDX-License-Identifier: GPL-2.0 |
0b24becc | 2 | /* |
2bd926b4 | 3 | * This file contains core generic KASAN code. |
0b24becc AR |
4 | * |
5 | * Copyright (c) 2014 Samsung Electronics Co., Ltd. | |
2baf9e89 | 6 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> |
0b24becc | 7 | * |
5d0926ef | 8 | * Some code borrowed from https://github.com/xairy/kasan-prototype by |
5f21f3a8 | 9 | * Andrey Konovalov <andreyknvl@gmail.com> |
0b24becc AR |
10 | * |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License version 2 as | |
13 | * published by the Free Software Foundation. | |
14 | * | |
15 | */ | |
16 | ||
17 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
18 | #define DISABLE_BRANCH_PROFILING | |
19 | ||
20 | #include <linux/export.h> | |
cd11016e | 21 | #include <linux/interrupt.h> |
0b24becc | 22 | #include <linux/init.h> |
cd11016e | 23 | #include <linux/kasan.h> |
0b24becc | 24 | #include <linux/kernel.h> |
45937254 | 25 | #include <linux/kmemleak.h> |
e3ae1163 | 26 | #include <linux/linkage.h> |
0b24becc | 27 | #include <linux/memblock.h> |
786a8959 | 28 | #include <linux/memory.h> |
0b24becc | 29 | #include <linux/mm.h> |
bebf56a1 | 30 | #include <linux/module.h> |
0b24becc AR |
31 | #include <linux/printk.h> |
32 | #include <linux/sched.h> | |
68db0cf1 | 33 | #include <linux/sched/task_stack.h> |
0b24becc AR |
34 | #include <linux/slab.h> |
35 | #include <linux/stacktrace.h> | |
36 | #include <linux/string.h> | |
37 | #include <linux/types.h> | |
a5af5aa8 | 38 | #include <linux/vmalloc.h> |
9f7d416c | 39 | #include <linux/bug.h> |
0b24becc AR |
40 | |
41 | #include "kasan.h" | |
0316bec2 | 42 | #include "../slab.h" |
0b24becc | 43 | |
0b24becc AR |
44 | /* |
45 | * All functions below always inlined so compiler could | |
46 | * perform better optimizations in each of __asan_loadX/__assn_storeX | |
47 | * depending on memory access size X. | |
48 | */ | |
49 | ||
50 | static __always_inline bool memory_is_poisoned_1(unsigned long addr) | |
51 | { | |
52 | s8 shadow_value = *(s8 *)kasan_mem_to_shadow((void *)addr); | |
53 | ||
54 | if (unlikely(shadow_value)) { | |
55 | s8 last_accessible_byte = addr & KASAN_SHADOW_MASK; | |
56 | return unlikely(last_accessible_byte >= shadow_value); | |
57 | } | |
58 | ||
59 | return false; | |
60 | } | |
61 | ||
c634d807 AR |
62 | static __always_inline bool memory_is_poisoned_2_4_8(unsigned long addr, |
63 | unsigned long size) | |
0b24becc | 64 | { |
c634d807 | 65 | u8 *shadow_addr = (u8 *)kasan_mem_to_shadow((void *)addr); |
0b24becc | 66 | |
c634d807 AR |
67 | /* |
68 | * Access crosses 8(shadow size)-byte boundary. Such access maps | |
69 | * into 2 shadow bytes, so we need to check them both. | |
70 | */ | |
71 | if (unlikely(((addr + size - 1) & KASAN_SHADOW_MASK) < size - 1)) | |
72 | return *shadow_addr || memory_is_poisoned_1(addr + size - 1); | |
0b24becc | 73 | |
c634d807 | 74 | return memory_is_poisoned_1(addr + size - 1); |
0b24becc AR |
75 | } |
76 | ||
77 | static __always_inline bool memory_is_poisoned_16(unsigned long addr) | |
78 | { | |
c634d807 | 79 | u16 *shadow_addr = (u16 *)kasan_mem_to_shadow((void *)addr); |
0b24becc | 80 | |
c634d807 AR |
81 | /* Unaligned 16-bytes access maps into 3 shadow bytes. */ |
82 | if (unlikely(!IS_ALIGNED(addr, KASAN_SHADOW_SCALE_SIZE))) | |
83 | return *shadow_addr || memory_is_poisoned_1(addr + 15); | |
0b24becc | 84 | |
c634d807 | 85 | return *shadow_addr; |
0b24becc AR |
86 | } |
87 | ||
f5bd62cd | 88 | static __always_inline unsigned long bytes_is_nonzero(const u8 *start, |
0b24becc AR |
89 | size_t size) |
90 | { | |
91 | while (size) { | |
92 | if (unlikely(*start)) | |
93 | return (unsigned long)start; | |
94 | start++; | |
95 | size--; | |
96 | } | |
97 | ||
98 | return 0; | |
99 | } | |
100 | ||
f5bd62cd | 101 | static __always_inline unsigned long memory_is_nonzero(const void *start, |
0b24becc AR |
102 | const void *end) |
103 | { | |
104 | unsigned int words; | |
105 | unsigned long ret; | |
106 | unsigned int prefix = (unsigned long)start % 8; | |
107 | ||
108 | if (end - start <= 16) | |
f5bd62cd | 109 | return bytes_is_nonzero(start, end - start); |
0b24becc AR |
110 | |
111 | if (prefix) { | |
112 | prefix = 8 - prefix; | |
f5bd62cd | 113 | ret = bytes_is_nonzero(start, prefix); |
0b24becc AR |
114 | if (unlikely(ret)) |
115 | return ret; | |
116 | start += prefix; | |
117 | } | |
118 | ||
119 | words = (end - start) / 8; | |
120 | while (words) { | |
121 | if (unlikely(*(u64 *)start)) | |
f5bd62cd | 122 | return bytes_is_nonzero(start, 8); |
0b24becc AR |
123 | start += 8; |
124 | words--; | |
125 | } | |
126 | ||
f5bd62cd | 127 | return bytes_is_nonzero(start, (end - start) % 8); |
0b24becc AR |
128 | } |
129 | ||
130 | static __always_inline bool memory_is_poisoned_n(unsigned long addr, | |
131 | size_t size) | |
132 | { | |
133 | unsigned long ret; | |
134 | ||
f5bd62cd | 135 | ret = memory_is_nonzero(kasan_mem_to_shadow((void *)addr), |
0b24becc AR |
136 | kasan_mem_to_shadow((void *)addr + size - 1) + 1); |
137 | ||
138 | if (unlikely(ret)) { | |
139 | unsigned long last_byte = addr + size - 1; | |
140 | s8 *last_shadow = (s8 *)kasan_mem_to_shadow((void *)last_byte); | |
141 | ||
142 | if (unlikely(ret != (unsigned long)last_shadow || | |
e0d57714 | 143 | ((long)(last_byte & KASAN_SHADOW_MASK) >= *last_shadow))) |
0b24becc AR |
144 | return true; |
145 | } | |
146 | return false; | |
147 | } | |
148 | ||
149 | static __always_inline bool memory_is_poisoned(unsigned long addr, size_t size) | |
150 | { | |
151 | if (__builtin_constant_p(size)) { | |
152 | switch (size) { | |
153 | case 1: | |
154 | return memory_is_poisoned_1(addr); | |
155 | case 2: | |
0b24becc | 156 | case 4: |
0b24becc | 157 | case 8: |
c634d807 | 158 | return memory_is_poisoned_2_4_8(addr, size); |
0b24becc AR |
159 | case 16: |
160 | return memory_is_poisoned_16(addr); | |
161 | default: | |
162 | BUILD_BUG(); | |
163 | } | |
164 | } | |
165 | ||
166 | return memory_is_poisoned_n(addr, size); | |
167 | } | |
168 | ||
b5f6e0fc | 169 | static __always_inline bool check_memory_region_inline(unsigned long addr, |
936bb4bb AR |
170 | size_t size, bool write, |
171 | unsigned long ret_ip) | |
0b24becc | 172 | { |
0b24becc | 173 | if (unlikely(size == 0)) |
b5f6e0fc | 174 | return true; |
0b24becc AR |
175 | |
176 | if (unlikely((void *)addr < | |
177 | kasan_shadow_to_mem((void *)KASAN_SHADOW_START))) { | |
936bb4bb | 178 | kasan_report(addr, size, write, ret_ip); |
b5f6e0fc | 179 | return false; |
0b24becc AR |
180 | } |
181 | ||
182 | if (likely(!memory_is_poisoned(addr, size))) | |
b5f6e0fc | 183 | return true; |
0b24becc | 184 | |
936bb4bb | 185 | kasan_report(addr, size, write, ret_ip); |
b5f6e0fc | 186 | return false; |
0b24becc AR |
187 | } |
188 | ||
b5f6e0fc | 189 | bool check_memory_region(unsigned long addr, size_t size, bool write, |
936bb4bb AR |
190 | unsigned long ret_ip) |
191 | { | |
b5f6e0fc | 192 | return check_memory_region_inline(addr, size, write, ret_ip); |
936bb4bb | 193 | } |
393f203f | 194 | |
55834c59 AP |
195 | void kasan_cache_shrink(struct kmem_cache *cache) |
196 | { | |
197 | quarantine_remove_cache(cache); | |
198 | } | |
199 | ||
f9fa1d91 | 200 | void kasan_cache_shutdown(struct kmem_cache *cache) |
55834c59 | 201 | { |
f9e13c0a SB |
202 | if (!__kmem_cache_empty(cache)) |
203 | quarantine_remove_cache(cache); | |
55834c59 AP |
204 | } |
205 | ||
bebf56a1 AR |
206 | static void register_global(struct kasan_global *global) |
207 | { | |
208 | size_t aligned_size = round_up(global->size, KASAN_SHADOW_SCALE_SIZE); | |
209 | ||
210 | kasan_unpoison_shadow(global->beg, global->size); | |
211 | ||
212 | kasan_poison_shadow(global->beg + aligned_size, | |
213 | global->size_with_redzone - aligned_size, | |
214 | KASAN_GLOBAL_REDZONE); | |
215 | } | |
216 | ||
217 | void __asan_register_globals(struct kasan_global *globals, size_t size) | |
218 | { | |
219 | int i; | |
220 | ||
221 | for (i = 0; i < size; i++) | |
222 | register_global(&globals[i]); | |
223 | } | |
224 | EXPORT_SYMBOL(__asan_register_globals); | |
225 | ||
226 | void __asan_unregister_globals(struct kasan_global *globals, size_t size) | |
227 | { | |
228 | } | |
229 | EXPORT_SYMBOL(__asan_unregister_globals); | |
230 | ||
936bb4bb AR |
231 | #define DEFINE_ASAN_LOAD_STORE(size) \ |
232 | void __asan_load##size(unsigned long addr) \ | |
233 | { \ | |
234 | check_memory_region_inline(addr, size, false, _RET_IP_);\ | |
235 | } \ | |
236 | EXPORT_SYMBOL(__asan_load##size); \ | |
237 | __alias(__asan_load##size) \ | |
238 | void __asan_load##size##_noabort(unsigned long); \ | |
239 | EXPORT_SYMBOL(__asan_load##size##_noabort); \ | |
240 | void __asan_store##size(unsigned long addr) \ | |
241 | { \ | |
242 | check_memory_region_inline(addr, size, true, _RET_IP_); \ | |
243 | } \ | |
244 | EXPORT_SYMBOL(__asan_store##size); \ | |
245 | __alias(__asan_store##size) \ | |
246 | void __asan_store##size##_noabort(unsigned long); \ | |
0b24becc AR |
247 | EXPORT_SYMBOL(__asan_store##size##_noabort) |
248 | ||
249 | DEFINE_ASAN_LOAD_STORE(1); | |
250 | DEFINE_ASAN_LOAD_STORE(2); | |
251 | DEFINE_ASAN_LOAD_STORE(4); | |
252 | DEFINE_ASAN_LOAD_STORE(8); | |
253 | DEFINE_ASAN_LOAD_STORE(16); | |
254 | ||
255 | void __asan_loadN(unsigned long addr, size_t size) | |
256 | { | |
936bb4bb | 257 | check_memory_region(addr, size, false, _RET_IP_); |
0b24becc AR |
258 | } |
259 | EXPORT_SYMBOL(__asan_loadN); | |
260 | ||
261 | __alias(__asan_loadN) | |
262 | void __asan_loadN_noabort(unsigned long, size_t); | |
263 | EXPORT_SYMBOL(__asan_loadN_noabort); | |
264 | ||
265 | void __asan_storeN(unsigned long addr, size_t size) | |
266 | { | |
936bb4bb | 267 | check_memory_region(addr, size, true, _RET_IP_); |
0b24becc AR |
268 | } |
269 | EXPORT_SYMBOL(__asan_storeN); | |
270 | ||
271 | __alias(__asan_storeN) | |
272 | void __asan_storeN_noabort(unsigned long, size_t); | |
273 | EXPORT_SYMBOL(__asan_storeN_noabort); | |
274 | ||
275 | /* to shut up compiler complaints */ | |
276 | void __asan_handle_no_return(void) {} | |
277 | EXPORT_SYMBOL(__asan_handle_no_return); | |
786a8959 | 278 | |
342061ee PL |
279 | /* Emitted by compiler to poison alloca()ed objects. */ |
280 | void __asan_alloca_poison(unsigned long addr, size_t size) | |
281 | { | |
282 | size_t rounded_up_size = round_up(size, KASAN_SHADOW_SCALE_SIZE); | |
283 | size_t padding_size = round_up(size, KASAN_ALLOCA_REDZONE_SIZE) - | |
284 | rounded_up_size; | |
285 | size_t rounded_down_size = round_down(size, KASAN_SHADOW_SCALE_SIZE); | |
286 | ||
287 | const void *left_redzone = (const void *)(addr - | |
288 | KASAN_ALLOCA_REDZONE_SIZE); | |
289 | const void *right_redzone = (const void *)(addr + rounded_up_size); | |
290 | ||
291 | WARN_ON(!IS_ALIGNED(addr, KASAN_ALLOCA_REDZONE_SIZE)); | |
292 | ||
293 | kasan_unpoison_shadow((const void *)(addr + rounded_down_size), | |
294 | size - rounded_down_size); | |
295 | kasan_poison_shadow(left_redzone, KASAN_ALLOCA_REDZONE_SIZE, | |
296 | KASAN_ALLOCA_LEFT); | |
297 | kasan_poison_shadow(right_redzone, | |
298 | padding_size + KASAN_ALLOCA_REDZONE_SIZE, | |
299 | KASAN_ALLOCA_RIGHT); | |
300 | } | |
301 | EXPORT_SYMBOL(__asan_alloca_poison); | |
302 | ||
303 | /* Emitted by compiler to unpoison alloca()ed areas when the stack unwinds. */ | |
304 | void __asan_allocas_unpoison(const void *stack_top, const void *stack_bottom) | |
305 | { | |
306 | if (unlikely(!stack_top || stack_top > stack_bottom)) | |
307 | return; | |
308 | ||
309 | kasan_unpoison_shadow(stack_top, stack_bottom - stack_top); | |
310 | } | |
311 | EXPORT_SYMBOL(__asan_allocas_unpoison); | |
312 | ||
d321599c AP |
313 | /* Emitted by the compiler to [un]poison local variables. */ |
314 | #define DEFINE_ASAN_SET_SHADOW(byte) \ | |
315 | void __asan_set_shadow_##byte(const void *addr, size_t size) \ | |
316 | { \ | |
317 | __memset((void *)addr, 0x##byte, size); \ | |
318 | } \ | |
319 | EXPORT_SYMBOL(__asan_set_shadow_##byte) | |
320 | ||
321 | DEFINE_ASAN_SET_SHADOW(00); | |
322 | DEFINE_ASAN_SET_SHADOW(f1); | |
323 | DEFINE_ASAN_SET_SHADOW(f2); | |
324 | DEFINE_ASAN_SET_SHADOW(f3); | |
325 | DEFINE_ASAN_SET_SHADOW(f5); | |
326 | DEFINE_ASAN_SET_SHADOW(f8); |