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c6d30853 AR |
1 | /* |
2 | * UBSAN error reporting functions | |
3 | * | |
4 | * Copyright (c) 2014 Samsung Electronics Co., Ltd. | |
5 | * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | */ | |
12 | ||
13 | #include <linux/bitops.h> | |
14 | #include <linux/bug.h> | |
15 | #include <linux/ctype.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/kernel.h> | |
18 | #include <linux/types.h> | |
19 | #include <linux/sched.h> | |
20 | ||
21 | #include "ubsan.h" | |
22 | ||
23 | const char *type_check_kinds[] = { | |
24 | "load of", | |
25 | "store to", | |
26 | "reference binding to", | |
27 | "member access within", | |
28 | "member call on", | |
29 | "constructor call on", | |
30 | "downcast of", | |
31 | "downcast of" | |
32 | }; | |
33 | ||
34 | #define REPORTED_BIT 31 | |
35 | ||
36 | #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN) | |
37 | #define COLUMN_MASK (~(1U << REPORTED_BIT)) | |
38 | #define LINE_MASK (~0U) | |
39 | #else | |
40 | #define COLUMN_MASK (~0U) | |
41 | #define LINE_MASK (~(1U << REPORTED_BIT)) | |
42 | #endif | |
43 | ||
44 | #define VALUE_LENGTH 40 | |
45 | ||
46 | static bool was_reported(struct source_location *location) | |
47 | { | |
48 | return test_and_set_bit(REPORTED_BIT, &location->reported); | |
49 | } | |
50 | ||
51 | static void print_source_location(const char *prefix, | |
52 | struct source_location *loc) | |
53 | { | |
54 | pr_err("%s %s:%d:%d\n", prefix, loc->file_name, | |
55 | loc->line & LINE_MASK, loc->column & COLUMN_MASK); | |
56 | } | |
57 | ||
58 | static bool suppress_report(struct source_location *loc) | |
59 | { | |
60 | return current->in_ubsan || was_reported(loc); | |
61 | } | |
62 | ||
63 | static bool type_is_int(struct type_descriptor *type) | |
64 | { | |
65 | return type->type_kind == type_kind_int; | |
66 | } | |
67 | ||
68 | static bool type_is_signed(struct type_descriptor *type) | |
69 | { | |
70 | WARN_ON(!type_is_int(type)); | |
71 | return type->type_info & 1; | |
72 | } | |
73 | ||
74 | static unsigned type_bit_width(struct type_descriptor *type) | |
75 | { | |
76 | return 1 << (type->type_info >> 1); | |
77 | } | |
78 | ||
79 | static bool is_inline_int(struct type_descriptor *type) | |
80 | { | |
81 | unsigned inline_bits = sizeof(unsigned long)*8; | |
82 | unsigned bits = type_bit_width(type); | |
83 | ||
84 | WARN_ON(!type_is_int(type)); | |
85 | ||
86 | return bits <= inline_bits; | |
87 | } | |
88 | ||
89 | static s_max get_signed_val(struct type_descriptor *type, unsigned long val) | |
90 | { | |
91 | if (is_inline_int(type)) { | |
92 | unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type); | |
93 | return ((s_max)val) << extra_bits >> extra_bits; | |
94 | } | |
95 | ||
96 | if (type_bit_width(type) == 64) | |
97 | return *(s64 *)val; | |
98 | ||
99 | return *(s_max *)val; | |
100 | } | |
101 | ||
102 | static bool val_is_negative(struct type_descriptor *type, unsigned long val) | |
103 | { | |
104 | return type_is_signed(type) && get_signed_val(type, val) < 0; | |
105 | } | |
106 | ||
107 | static u_max get_unsigned_val(struct type_descriptor *type, unsigned long val) | |
108 | { | |
109 | if (is_inline_int(type)) | |
110 | return val; | |
111 | ||
112 | if (type_bit_width(type) == 64) | |
113 | return *(u64 *)val; | |
114 | ||
115 | return *(u_max *)val; | |
116 | } | |
117 | ||
118 | static void val_to_string(char *str, size_t size, struct type_descriptor *type, | |
119 | unsigned long value) | |
120 | { | |
121 | if (type_is_int(type)) { | |
122 | if (type_bit_width(type) == 128) { | |
123 | #if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) | |
124 | u_max val = get_unsigned_val(type, value); | |
125 | ||
126 | scnprintf(str, size, "0x%08x%08x%08x%08x", | |
127 | (u32)(val >> 96), | |
128 | (u32)(val >> 64), | |
129 | (u32)(val >> 32), | |
130 | (u32)(val)); | |
131 | #else | |
132 | WARN_ON(1); | |
133 | #endif | |
134 | } else if (type_is_signed(type)) { | |
135 | scnprintf(str, size, "%lld", | |
136 | (s64)get_signed_val(type, value)); | |
137 | } else { | |
138 | scnprintf(str, size, "%llu", | |
139 | (u64)get_unsigned_val(type, value)); | |
140 | } | |
141 | } | |
142 | } | |
143 | ||
144 | static bool location_is_valid(struct source_location *loc) | |
145 | { | |
146 | return loc->file_name != NULL; | |
147 | } | |
148 | ||
149 | static DEFINE_SPINLOCK(report_lock); | |
150 | ||
151 | static void ubsan_prologue(struct source_location *location, | |
152 | unsigned long *flags) | |
153 | { | |
154 | current->in_ubsan++; | |
155 | spin_lock_irqsave(&report_lock, *flags); | |
156 | ||
157 | pr_err("========================================" | |
158 | "========================================\n"); | |
159 | print_source_location("UBSAN: Undefined behaviour in", location); | |
160 | } | |
161 | ||
162 | static void ubsan_epilogue(unsigned long *flags) | |
163 | { | |
164 | dump_stack(); | |
165 | pr_err("========================================" | |
166 | "========================================\n"); | |
167 | spin_unlock_irqrestore(&report_lock, *flags); | |
168 | current->in_ubsan--; | |
169 | } | |
170 | ||
171 | static void handle_overflow(struct overflow_data *data, unsigned long lhs, | |
172 | unsigned long rhs, char op) | |
173 | { | |
174 | ||
175 | struct type_descriptor *type = data->type; | |
176 | unsigned long flags; | |
177 | char lhs_val_str[VALUE_LENGTH]; | |
178 | char rhs_val_str[VALUE_LENGTH]; | |
179 | ||
180 | if (suppress_report(&data->location)) | |
181 | return; | |
182 | ||
183 | ubsan_prologue(&data->location, &flags); | |
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 | ||
195 | ubsan_epilogue(&flags); | |
196 | } | |
197 | ||
198 | void __ubsan_handle_add_overflow(struct overflow_data *data, | |
199 | unsigned long lhs, | |
200 | unsigned long rhs) | |
201 | { | |
202 | ||
203 | handle_overflow(data, lhs, rhs, '+'); | |
204 | } | |
205 | EXPORT_SYMBOL(__ubsan_handle_add_overflow); | |
206 | ||
207 | void __ubsan_handle_sub_overflow(struct overflow_data *data, | |
208 | unsigned long lhs, | |
209 | unsigned long rhs) | |
210 | { | |
211 | handle_overflow(data, lhs, rhs, '-'); | |
212 | } | |
213 | EXPORT_SYMBOL(__ubsan_handle_sub_overflow); | |
214 | ||
215 | void __ubsan_handle_mul_overflow(struct overflow_data *data, | |
216 | unsigned long lhs, | |
217 | unsigned long rhs) | |
218 | { | |
219 | handle_overflow(data, lhs, rhs, '*'); | |
220 | } | |
221 | EXPORT_SYMBOL(__ubsan_handle_mul_overflow); | |
222 | ||
223 | void __ubsan_handle_negate_overflow(struct overflow_data *data, | |
224 | unsigned long old_val) | |
225 | { | |
226 | unsigned long flags; | |
227 | char old_val_str[VALUE_LENGTH]; | |
228 | ||
229 | if (suppress_report(&data->location)) | |
230 | return; | |
231 | ||
232 | ubsan_prologue(&data->location, &flags); | |
233 | ||
234 | val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val); | |
235 | ||
236 | pr_err("negation of %s cannot be represented in type %s:\n", | |
237 | old_val_str, data->type->type_name); | |
238 | ||
239 | ubsan_epilogue(&flags); | |
240 | } | |
241 | EXPORT_SYMBOL(__ubsan_handle_negate_overflow); | |
242 | ||
243 | ||
244 | void __ubsan_handle_divrem_overflow(struct overflow_data *data, | |
245 | unsigned long lhs, | |
246 | unsigned long rhs) | |
247 | { | |
248 | unsigned long flags; | |
249 | char rhs_val_str[VALUE_LENGTH]; | |
250 | ||
251 | if (suppress_report(&data->location)) | |
252 | return; | |
253 | ||
254 | ubsan_prologue(&data->location, &flags); | |
255 | ||
256 | val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs); | |
257 | ||
258 | if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1) | |
259 | pr_err("division of %s by -1 cannot be represented in type %s\n", | |
260 | rhs_val_str, data->type->type_name); | |
261 | else | |
262 | pr_err("division by zero\n"); | |
263 | ||
264 | ubsan_epilogue(&flags); | |
265 | } | |
266 | EXPORT_SYMBOL(__ubsan_handle_divrem_overflow); | |
267 | ||
883a671e | 268 | static void handle_null_ptr_deref(struct type_mismatch_data_common *data) |
c6d30853 AR |
269 | { |
270 | unsigned long flags; | |
271 | ||
883a671e | 272 | if (suppress_report(data->location)) |
c6d30853 AR |
273 | return; |
274 | ||
883a671e | 275 | ubsan_prologue(data->location, &flags); |
c6d30853 AR |
276 | |
277 | pr_err("%s null pointer of type %s\n", | |
278 | type_check_kinds[data->type_check_kind], | |
279 | data->type->type_name); | |
280 | ||
281 | ubsan_epilogue(&flags); | |
282 | } | |
283 | ||
883a671e | 284 | static void handle_misaligned_access(struct type_mismatch_data_common *data, |
c6d30853 AR |
285 | unsigned long ptr) |
286 | { | |
287 | unsigned long flags; | |
288 | ||
883a671e | 289 | if (suppress_report(data->location)) |
c6d30853 AR |
290 | return; |
291 | ||
883a671e | 292 | ubsan_prologue(data->location, &flags); |
c6d30853 AR |
293 | |
294 | pr_err("%s misaligned address %p for type %s\n", | |
295 | type_check_kinds[data->type_check_kind], | |
296 | (void *)ptr, data->type->type_name); | |
297 | pr_err("which requires %ld byte alignment\n", data->alignment); | |
298 | ||
299 | ubsan_epilogue(&flags); | |
300 | } | |
301 | ||
883a671e | 302 | static void handle_object_size_mismatch(struct type_mismatch_data_common *data, |
c6d30853 AR |
303 | unsigned long ptr) |
304 | { | |
305 | unsigned long flags; | |
306 | ||
883a671e | 307 | if (suppress_report(data->location)) |
c6d30853 AR |
308 | return; |
309 | ||
883a671e | 310 | ubsan_prologue(data->location, &flags); |
901d805c | 311 | pr_err("%s address %p with insufficient space\n", |
c6d30853 AR |
312 | type_check_kinds[data->type_check_kind], |
313 | (void *) ptr); | |
314 | pr_err("for an object of type %s\n", data->type->type_name); | |
315 | ubsan_epilogue(&flags); | |
316 | } | |
317 | ||
883a671e | 318 | static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data, |
c6d30853 AR |
319 | unsigned long ptr) |
320 | { | |
321 | ||
322 | if (!ptr) | |
323 | handle_null_ptr_deref(data); | |
324 | else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) | |
13f5ab81 | 325 | handle_misaligned_access(data, ptr); |
c6d30853 AR |
326 | else |
327 | handle_object_size_mismatch(data, ptr); | |
328 | } | |
883a671e AR |
329 | |
330 | void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, | |
331 | unsigned long ptr) | |
332 | { | |
333 | struct type_mismatch_data_common common_data = { | |
334 | .location = &data->location, | |
335 | .type = data->type, | |
336 | .alignment = data->alignment, | |
337 | .type_check_kind = data->type_check_kind | |
338 | }; | |
339 | ||
340 | ubsan_type_mismatch_common(&common_data, ptr); | |
341 | } | |
c6d30853 AR |
342 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch); |
343 | ||
883a671e AR |
344 | void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data, |
345 | unsigned long ptr) | |
346 | { | |
347 | ||
348 | struct type_mismatch_data_common common_data = { | |
349 | .location = &data->location, | |
350 | .type = data->type, | |
351 | .alignment = 1UL << data->log_alignment, | |
352 | .type_check_kind = data->type_check_kind | |
353 | }; | |
354 | ||
355 | ubsan_type_mismatch_common(&common_data, ptr); | |
356 | } | |
357 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1); | |
358 | ||
c6d30853 AR |
359 | void __ubsan_handle_nonnull_return(struct nonnull_return_data *data) |
360 | { | |
361 | unsigned long flags; | |
362 | ||
363 | if (suppress_report(&data->location)) | |
364 | return; | |
365 | ||
366 | ubsan_prologue(&data->location, &flags); | |
367 | ||
368 | pr_err("null pointer returned from function declared to never return null\n"); | |
369 | ||
370 | if (location_is_valid(&data->attr_location)) | |
371 | print_source_location("returns_nonnull attribute specified in", | |
372 | &data->attr_location); | |
373 | ||
374 | ubsan_epilogue(&flags); | |
375 | } | |
376 | EXPORT_SYMBOL(__ubsan_handle_nonnull_return); | |
377 | ||
378 | void __ubsan_handle_vla_bound_not_positive(struct vla_bound_data *data, | |
379 | unsigned long bound) | |
380 | { | |
381 | unsigned long flags; | |
382 | char bound_str[VALUE_LENGTH]; | |
383 | ||
384 | if (suppress_report(&data->location)) | |
385 | return; | |
386 | ||
387 | ubsan_prologue(&data->location, &flags); | |
388 | ||
389 | val_to_string(bound_str, sizeof(bound_str), data->type, bound); | |
390 | pr_err("variable length array bound value %s <= 0\n", bound_str); | |
391 | ||
392 | ubsan_epilogue(&flags); | |
393 | } | |
394 | EXPORT_SYMBOL(__ubsan_handle_vla_bound_not_positive); | |
395 | ||
396 | void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, | |
397 | unsigned long index) | |
398 | { | |
399 | unsigned long flags; | |
400 | char index_str[VALUE_LENGTH]; | |
401 | ||
402 | if (suppress_report(&data->location)) | |
403 | return; | |
404 | ||
405 | ubsan_prologue(&data->location, &flags); | |
406 | ||
407 | val_to_string(index_str, sizeof(index_str), data->index_type, index); | |
408 | pr_err("index %s is out of range for type %s\n", index_str, | |
409 | data->array_type->type_name); | |
410 | ubsan_epilogue(&flags); | |
411 | } | |
412 | EXPORT_SYMBOL(__ubsan_handle_out_of_bounds); | |
413 | ||
414 | void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data, | |
415 | unsigned long lhs, unsigned long rhs) | |
416 | { | |
417 | unsigned long flags; | |
418 | struct type_descriptor *rhs_type = data->rhs_type; | |
419 | struct type_descriptor *lhs_type = data->lhs_type; | |
420 | char rhs_str[VALUE_LENGTH]; | |
421 | char lhs_str[VALUE_LENGTH]; | |
422 | ||
423 | if (suppress_report(&data->location)) | |
424 | return; | |
425 | ||
426 | ubsan_prologue(&data->location, &flags); | |
427 | ||
428 | val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs); | |
429 | val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs); | |
430 | ||
431 | if (val_is_negative(rhs_type, rhs)) | |
432 | pr_err("shift exponent %s is negative\n", rhs_str); | |
433 | ||
434 | else if (get_unsigned_val(rhs_type, rhs) >= | |
435 | type_bit_width(lhs_type)) | |
436 | pr_err("shift exponent %s is too large for %u-bit type %s\n", | |
437 | rhs_str, | |
438 | type_bit_width(lhs_type), | |
439 | lhs_type->type_name); | |
440 | else if (val_is_negative(lhs_type, lhs)) | |
441 | pr_err("left shift of negative value %s\n", | |
442 | lhs_str); | |
443 | else | |
444 | pr_err("left shift of %s by %s places cannot be" | |
445 | " represented in type %s\n", | |
446 | lhs_str, rhs_str, | |
447 | lhs_type->type_name); | |
448 | ||
449 | ubsan_epilogue(&flags); | |
450 | } | |
451 | EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds); | |
452 | ||
453 | ||
454 | void __noreturn | |
455 | __ubsan_handle_builtin_unreachable(struct unreachable_data *data) | |
456 | { | |
457 | unsigned long flags; | |
458 | ||
459 | ubsan_prologue(&data->location, &flags); | |
460 | pr_err("calling __builtin_unreachable()\n"); | |
461 | ubsan_epilogue(&flags); | |
462 | panic("can't return from __builtin_unreachable()"); | |
463 | } | |
464 | EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable); | |
465 | ||
466 | void __ubsan_handle_load_invalid_value(struct invalid_value_data *data, | |
467 | unsigned long val) | |
468 | { | |
469 | unsigned long flags; | |
470 | char val_str[VALUE_LENGTH]; | |
471 | ||
472 | if (suppress_report(&data->location)) | |
473 | return; | |
474 | ||
475 | ubsan_prologue(&data->location, &flags); | |
476 | ||
477 | val_to_string(val_str, sizeof(val_str), data->type, val); | |
478 | ||
479 | pr_err("load of value %s is not a valid value for type %s\n", | |
480 | val_str, data->type->type_name); | |
481 | ||
482 | ubsan_epilogue(&flags); | |
483 | } | |
484 | EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); |