Commit | Line | Data |
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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
c6d30853 AR |
2 | /* |
3 | * UBSAN error reporting functions | |
4 | * | |
5 | * Copyright (c) 2014 Samsung Electronics Co., Ltd. | |
6 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> | |
c6d30853 AR |
7 | */ |
8 | ||
9 | #include <linux/bitops.h> | |
10 | #include <linux/bug.h> | |
11 | #include <linux/ctype.h> | |
12 | #include <linux/init.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/types.h> | |
15 | #include <linux/sched.h> | |
d08965a2 | 16 | #include <linux/uaccess.h> |
c6d30853 AR |
17 | |
18 | #include "ubsan.h" | |
19 | ||
20 | const char *type_check_kinds[] = { | |
21 | "load of", | |
22 | "store to", | |
23 | "reference binding to", | |
24 | "member access within", | |
25 | "member call on", | |
26 | "constructor call on", | |
27 | "downcast of", | |
28 | "downcast of" | |
29 | }; | |
30 | ||
31 | #define REPORTED_BIT 31 | |
32 | ||
33 | #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN) | |
34 | #define COLUMN_MASK (~(1U << REPORTED_BIT)) | |
35 | #define LINE_MASK (~0U) | |
36 | #else | |
37 | #define COLUMN_MASK (~0U) | |
38 | #define LINE_MASK (~(1U << REPORTED_BIT)) | |
39 | #endif | |
40 | ||
41 | #define VALUE_LENGTH 40 | |
42 | ||
43 | static bool was_reported(struct source_location *location) | |
44 | { | |
45 | return test_and_set_bit(REPORTED_BIT, &location->reported); | |
46 | } | |
47 | ||
48 | static void print_source_location(const char *prefix, | |
49 | struct source_location *loc) | |
50 | { | |
51 | pr_err("%s %s:%d:%d\n", prefix, loc->file_name, | |
52 | loc->line & LINE_MASK, loc->column & COLUMN_MASK); | |
53 | } | |
54 | ||
55 | static bool suppress_report(struct source_location *loc) | |
56 | { | |
57 | return current->in_ubsan || was_reported(loc); | |
58 | } | |
59 | ||
60 | static bool type_is_int(struct type_descriptor *type) | |
61 | { | |
62 | return type->type_kind == type_kind_int; | |
63 | } | |
64 | ||
65 | static bool type_is_signed(struct type_descriptor *type) | |
66 | { | |
67 | WARN_ON(!type_is_int(type)); | |
68 | return type->type_info & 1; | |
69 | } | |
70 | ||
71 | static unsigned type_bit_width(struct type_descriptor *type) | |
72 | { | |
73 | return 1 << (type->type_info >> 1); | |
74 | } | |
75 | ||
76 | static bool is_inline_int(struct type_descriptor *type) | |
77 | { | |
78 | unsigned inline_bits = sizeof(unsigned long)*8; | |
79 | unsigned bits = type_bit_width(type); | |
80 | ||
81 | WARN_ON(!type_is_int(type)); | |
82 | ||
83 | return bits <= inline_bits; | |
84 | } | |
85 | ||
f0996bc2 | 86 | static s_max get_signed_val(struct type_descriptor *type, void *val) |
c6d30853 AR |
87 | { |
88 | if (is_inline_int(type)) { | |
89 | unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type); | |
f0996bc2 AR |
90 | unsigned long ulong_val = (unsigned long)val; |
91 | ||
92 | return ((s_max)ulong_val) << extra_bits >> extra_bits; | |
c6d30853 AR |
93 | } |
94 | ||
95 | if (type_bit_width(type) == 64) | |
96 | return *(s64 *)val; | |
97 | ||
98 | return *(s_max *)val; | |
99 | } | |
100 | ||
f0996bc2 | 101 | static bool val_is_negative(struct type_descriptor *type, void *val) |
c6d30853 AR |
102 | { |
103 | return type_is_signed(type) && get_signed_val(type, val) < 0; | |
104 | } | |
105 | ||
f0996bc2 | 106 | static u_max get_unsigned_val(struct type_descriptor *type, void *val) |
c6d30853 AR |
107 | { |
108 | if (is_inline_int(type)) | |
f0996bc2 | 109 | return (unsigned long)val; |
c6d30853 AR |
110 | |
111 | if (type_bit_width(type) == 64) | |
112 | return *(u64 *)val; | |
113 | ||
114 | return *(u_max *)val; | |
115 | } | |
116 | ||
117 | static void val_to_string(char *str, size_t size, struct type_descriptor *type, | |
f0996bc2 | 118 | void *value) |
c6d30853 AR |
119 | { |
120 | if (type_is_int(type)) { | |
121 | if (type_bit_width(type) == 128) { | |
c12d3362 | 122 | #if defined(CONFIG_ARCH_SUPPORTS_INT128) |
c6d30853 AR |
123 | u_max val = get_unsigned_val(type, value); |
124 | ||
125 | scnprintf(str, size, "0x%08x%08x%08x%08x", | |
126 | (u32)(val >> 96), | |
127 | (u32)(val >> 64), | |
128 | (u32)(val >> 32), | |
129 | (u32)(val)); | |
130 | #else | |
131 | WARN_ON(1); | |
132 | #endif | |
133 | } else if (type_is_signed(type)) { | |
134 | scnprintf(str, size, "%lld", | |
135 | (s64)get_signed_val(type, value)); | |
136 | } else { | |
137 | scnprintf(str, size, "%llu", | |
138 | (u64)get_unsigned_val(type, value)); | |
139 | } | |
140 | } | |
141 | } | |
142 | ||
ce5c31db | 143 | static void ubsan_prologue(struct source_location *location) |
c6d30853 AR |
144 | { |
145 | current->in_ubsan++; | |
c6d30853 AR |
146 | |
147 | pr_err("========================================" | |
148 | "========================================\n"); | |
149 | print_source_location("UBSAN: Undefined behaviour in", location); | |
150 | } | |
151 | ||
ce5c31db | 152 | static void ubsan_epilogue(void) |
c6d30853 AR |
153 | { |
154 | dump_stack(); | |
155 | pr_err("========================================" | |
156 | "========================================\n"); | |
ce5c31db | 157 | |
c6d30853 | 158 | current->in_ubsan--; |
1d28c8d6 KC |
159 | |
160 | if (panic_on_warn) { | |
161 | /* | |
162 | * This thread may hit another WARN() in the panic path. | |
163 | * Resetting this prevents additional WARN() from panicking the | |
164 | * system on this thread. Other threads are blocked by the | |
165 | * panic_mutex in panic(). | |
166 | */ | |
167 | panic_on_warn = 0; | |
168 | panic("panic_on_warn set ...\n"); | |
169 | } | |
c6d30853 AR |
170 | } |
171 | ||
f0996bc2 AR |
172 | static void handle_overflow(struct overflow_data *data, void *lhs, |
173 | void *rhs, char op) | |
c6d30853 AR |
174 | { |
175 | ||
176 | struct type_descriptor *type = data->type; | |
c6d30853 AR |
177 | char lhs_val_str[VALUE_LENGTH]; |
178 | char rhs_val_str[VALUE_LENGTH]; | |
179 | ||
180 | if (suppress_report(&data->location)) | |
181 | return; | |
182 | ||
ce5c31db | 183 | ubsan_prologue(&data->location); |
c6d30853 AR |
184 | |
185 | val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs); | |
186 | val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs); | |
187 | pr_err("%s integer overflow:\n", | |
188 | type_is_signed(type) ? "signed" : "unsigned"); | |
189 | pr_err("%s %c %s cannot be represented in type %s\n", | |
190 | lhs_val_str, | |
191 | op, | |
192 | rhs_val_str, | |
193 | type->type_name); | |
194 | ||
ce5c31db | 195 | ubsan_epilogue(); |
c6d30853 AR |
196 | } |
197 | ||
198 | void __ubsan_handle_add_overflow(struct overflow_data *data, | |
f0996bc2 | 199 | void *lhs, void *rhs) |
c6d30853 AR |
200 | { |
201 | ||
202 | handle_overflow(data, lhs, rhs, '+'); | |
203 | } | |
204 | EXPORT_SYMBOL(__ubsan_handle_add_overflow); | |
205 | ||
206 | void __ubsan_handle_sub_overflow(struct overflow_data *data, | |
f0996bc2 | 207 | void *lhs, void *rhs) |
c6d30853 AR |
208 | { |
209 | handle_overflow(data, lhs, rhs, '-'); | |
210 | } | |
211 | EXPORT_SYMBOL(__ubsan_handle_sub_overflow); | |
212 | ||
213 | void __ubsan_handle_mul_overflow(struct overflow_data *data, | |
f0996bc2 | 214 | void *lhs, void *rhs) |
c6d30853 AR |
215 | { |
216 | handle_overflow(data, lhs, rhs, '*'); | |
217 | } | |
218 | EXPORT_SYMBOL(__ubsan_handle_mul_overflow); | |
219 | ||
220 | void __ubsan_handle_negate_overflow(struct overflow_data *data, | |
f0996bc2 | 221 | void *old_val) |
c6d30853 | 222 | { |
c6d30853 AR |
223 | char old_val_str[VALUE_LENGTH]; |
224 | ||
225 | if (suppress_report(&data->location)) | |
226 | return; | |
227 | ||
ce5c31db | 228 | ubsan_prologue(&data->location); |
c6d30853 AR |
229 | |
230 | val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val); | |
231 | ||
232 | pr_err("negation of %s cannot be represented in type %s:\n", | |
233 | old_val_str, data->type->type_name); | |
234 | ||
ce5c31db | 235 | ubsan_epilogue(); |
c6d30853 AR |
236 | } |
237 | EXPORT_SYMBOL(__ubsan_handle_negate_overflow); | |
238 | ||
239 | ||
240 | void __ubsan_handle_divrem_overflow(struct overflow_data *data, | |
f0996bc2 | 241 | void *lhs, void *rhs) |
c6d30853 | 242 | { |
c6d30853 AR |
243 | char rhs_val_str[VALUE_LENGTH]; |
244 | ||
245 | if (suppress_report(&data->location)) | |
246 | return; | |
247 | ||
ce5c31db | 248 | ubsan_prologue(&data->location); |
c6d30853 AR |
249 | |
250 | val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs); | |
251 | ||
252 | if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1) | |
253 | pr_err("division of %s by -1 cannot be represented in type %s\n", | |
254 | rhs_val_str, data->type->type_name); | |
255 | else | |
256 | pr_err("division by zero\n"); | |
257 | ||
ce5c31db | 258 | ubsan_epilogue(); |
c6d30853 AR |
259 | } |
260 | EXPORT_SYMBOL(__ubsan_handle_divrem_overflow); | |
261 | ||
42440c1f | 262 | static void handle_null_ptr_deref(struct type_mismatch_data_common *data) |
c6d30853 | 263 | { |
42440c1f | 264 | if (suppress_report(data->location)) |
c6d30853 AR |
265 | return; |
266 | ||
ce5c31db | 267 | ubsan_prologue(data->location); |
c6d30853 AR |
268 | |
269 | pr_err("%s null pointer of type %s\n", | |
270 | type_check_kinds[data->type_check_kind], | |
271 | data->type->type_name); | |
272 | ||
ce5c31db | 273 | ubsan_epilogue(); |
c6d30853 AR |
274 | } |
275 | ||
42440c1f | 276 | static void handle_misaligned_access(struct type_mismatch_data_common *data, |
c6d30853 AR |
277 | unsigned long ptr) |
278 | { | |
42440c1f | 279 | if (suppress_report(data->location)) |
c6d30853 AR |
280 | return; |
281 | ||
ce5c31db | 282 | ubsan_prologue(data->location); |
c6d30853 AR |
283 | |
284 | pr_err("%s misaligned address %p for type %s\n", | |
285 | type_check_kinds[data->type_check_kind], | |
286 | (void *)ptr, data->type->type_name); | |
287 | pr_err("which requires %ld byte alignment\n", data->alignment); | |
288 | ||
ce5c31db | 289 | ubsan_epilogue(); |
c6d30853 AR |
290 | } |
291 | ||
42440c1f | 292 | static void handle_object_size_mismatch(struct type_mismatch_data_common *data, |
c6d30853 AR |
293 | unsigned long ptr) |
294 | { | |
42440c1f | 295 | if (suppress_report(data->location)) |
c6d30853 AR |
296 | return; |
297 | ||
ce5c31db | 298 | ubsan_prologue(data->location); |
901d805c | 299 | pr_err("%s address %p with insufficient space\n", |
c6d30853 AR |
300 | type_check_kinds[data->type_check_kind], |
301 | (void *) ptr); | |
302 | pr_err("for an object of type %s\n", data->type->type_name); | |
ce5c31db | 303 | ubsan_epilogue(); |
c6d30853 AR |
304 | } |
305 | ||
42440c1f | 306 | static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data, |
c6d30853 AR |
307 | unsigned long ptr) |
308 | { | |
d08965a2 | 309 | unsigned long flags = user_access_save(); |
c6d30853 AR |
310 | |
311 | if (!ptr) | |
312 | handle_null_ptr_deref(data); | |
313 | else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) | |
b8fe1120 | 314 | handle_misaligned_access(data, ptr); |
c6d30853 AR |
315 | else |
316 | handle_object_size_mismatch(data, ptr); | |
d08965a2 PZ |
317 | |
318 | user_access_restore(flags); | |
c6d30853 | 319 | } |
42440c1f AR |
320 | |
321 | void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, | |
f0996bc2 | 322 | void *ptr) |
42440c1f AR |
323 | { |
324 | struct type_mismatch_data_common common_data = { | |
325 | .location = &data->location, | |
326 | .type = data->type, | |
327 | .alignment = data->alignment, | |
328 | .type_check_kind = data->type_check_kind | |
329 | }; | |
330 | ||
f0996bc2 | 331 | ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
42440c1f | 332 | } |
c6d30853 AR |
333 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch); |
334 | ||
42440c1f | 335 | void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data, |
f0996bc2 | 336 | void *ptr) |
42440c1f AR |
337 | { |
338 | ||
339 | struct type_mismatch_data_common common_data = { | |
340 | .location = &data->location, | |
341 | .type = data->type, | |
342 | .alignment = 1UL << data->log_alignment, | |
343 | .type_check_kind = data->type_check_kind | |
344 | }; | |
345 | ||
f0996bc2 | 346 | ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
42440c1f AR |
347 | } |
348 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1); | |
349 | ||
f0996bc2 | 350 | void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, void *index) |
c6d30853 | 351 | { |
c6d30853 AR |
352 | char index_str[VALUE_LENGTH]; |
353 | ||
354 | if (suppress_report(&data->location)) | |
355 | return; | |
356 | ||
ce5c31db | 357 | ubsan_prologue(&data->location); |
c6d30853 AR |
358 | |
359 | val_to_string(index_str, sizeof(index_str), data->index_type, index); | |
360 | pr_err("index %s is out of range for type %s\n", index_str, | |
361 | data->array_type->type_name); | |
ce5c31db | 362 | ubsan_epilogue(); |
c6d30853 AR |
363 | } |
364 | EXPORT_SYMBOL(__ubsan_handle_out_of_bounds); | |
365 | ||
366 | void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data, | |
f0996bc2 | 367 | void *lhs, void *rhs) |
c6d30853 | 368 | { |
c6d30853 AR |
369 | struct type_descriptor *rhs_type = data->rhs_type; |
370 | struct type_descriptor *lhs_type = data->lhs_type; | |
371 | char rhs_str[VALUE_LENGTH]; | |
372 | char lhs_str[VALUE_LENGTH]; | |
9a50dcaf | 373 | unsigned long ua_flags = user_access_save(); |
c6d30853 AR |
374 | |
375 | if (suppress_report(&data->location)) | |
9a50dcaf | 376 | goto out; |
c6d30853 | 377 | |
ce5c31db | 378 | ubsan_prologue(&data->location); |
c6d30853 AR |
379 | |
380 | val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs); | |
381 | val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs); | |
382 | ||
383 | if (val_is_negative(rhs_type, rhs)) | |
384 | pr_err("shift exponent %s is negative\n", rhs_str); | |
385 | ||
386 | else if (get_unsigned_val(rhs_type, rhs) >= | |
387 | type_bit_width(lhs_type)) | |
388 | pr_err("shift exponent %s is too large for %u-bit type %s\n", | |
389 | rhs_str, | |
390 | type_bit_width(lhs_type), | |
391 | lhs_type->type_name); | |
392 | else if (val_is_negative(lhs_type, lhs)) | |
393 | pr_err("left shift of negative value %s\n", | |
394 | lhs_str); | |
395 | else | |
396 | pr_err("left shift of %s by %s places cannot be" | |
397 | " represented in type %s\n", | |
398 | lhs_str, rhs_str, | |
399 | lhs_type->type_name); | |
400 | ||
ce5c31db | 401 | ubsan_epilogue(); |
9a50dcaf PZ |
402 | out: |
403 | user_access_restore(ua_flags); | |
c6d30853 AR |
404 | } |
405 | EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds); | |
406 | ||
407 | ||
1c23b410 | 408 | void __ubsan_handle_builtin_unreachable(struct unreachable_data *data) |
c6d30853 | 409 | { |
ce5c31db | 410 | ubsan_prologue(&data->location); |
c6d30853 | 411 | pr_err("calling __builtin_unreachable()\n"); |
ce5c31db | 412 | ubsan_epilogue(); |
c6d30853 AR |
413 | panic("can't return from __builtin_unreachable()"); |
414 | } | |
415 | EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable); | |
416 | ||
417 | void __ubsan_handle_load_invalid_value(struct invalid_value_data *data, | |
f0996bc2 | 418 | void *val) |
c6d30853 | 419 | { |
c6d30853 AR |
420 | char val_str[VALUE_LENGTH]; |
421 | ||
422 | if (suppress_report(&data->location)) | |
423 | return; | |
424 | ||
ce5c31db | 425 | ubsan_prologue(&data->location); |
c6d30853 AR |
426 | |
427 | val_to_string(val_str, sizeof(val_str), data->type, val); | |
428 | ||
429 | pr_err("load of value %s is not a valid value for type %s\n", | |
430 | val_str, data->type->type_name); | |
431 | ||
ce5c31db | 432 | ubsan_epilogue(); |
c6d30853 AR |
433 | } |
434 | EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); |