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> |
25b84002 | 17 | #include <linux/ubsan.h> |
1195505f | 18 | #include <kunit/test-bug.h> |
c6d30853 AR |
19 | |
20 | #include "ubsan.h" | |
21 | ||
25b84002 KC |
22 | #ifdef CONFIG_UBSAN_TRAP |
23 | /* | |
24 | * Only include matches for UBSAN checks that are actually compiled in. | |
25 | * The mappings of struct SanitizerKind (the -fsanitize=xxx args) to | |
26 | * enum SanitizerHandler (the traps) in Clang is in clang/lib/CodeGen/. | |
27 | */ | |
28 | const char *report_ubsan_failure(struct pt_regs *regs, u32 check_type) | |
29 | { | |
30 | switch (check_type) { | |
31 | #ifdef CONFIG_UBSAN_BOUNDS | |
32 | /* | |
33 | * SanitizerKind::ArrayBounds and SanitizerKind::LocalBounds | |
34 | * emit SanitizerHandler::OutOfBounds. | |
35 | */ | |
36 | case ubsan_out_of_bounds: | |
37 | return "UBSAN: array index out of bounds"; | |
38 | #endif | |
39 | #ifdef CONFIG_UBSAN_SHIFT | |
40 | /* | |
41 | * SanitizerKind::ShiftBase and SanitizerKind::ShiftExponent | |
42 | * emit SanitizerHandler::ShiftOutOfBounds. | |
43 | */ | |
44 | case ubsan_shift_out_of_bounds: | |
45 | return "UBSAN: shift out of bounds"; | |
46 | #endif | |
47 | #ifdef CONFIG_UBSAN_DIV_ZERO | |
48 | /* | |
49 | * SanitizerKind::IntegerDivideByZero emits | |
50 | * SanitizerHandler::DivremOverflow. | |
51 | */ | |
52 | case ubsan_divrem_overflow: | |
53 | return "UBSAN: divide/remainder overflow"; | |
54 | #endif | |
55 | #ifdef CONFIG_UBSAN_UNREACHABLE | |
56 | /* | |
57 | * SanitizerKind::Unreachable emits | |
58 | * SanitizerHandler::BuiltinUnreachable. | |
59 | */ | |
60 | case ubsan_builtin_unreachable: | |
61 | return "UBSAN: unreachable code"; | |
62 | #endif | |
63 | #if defined(CONFIG_UBSAN_BOOL) || defined(CONFIG_UBSAN_ENUM) | |
64 | /* | |
65 | * SanitizerKind::Bool and SanitizerKind::Enum emit | |
66 | * SanitizerHandler::LoadInvalidValue. | |
67 | */ | |
68 | case ubsan_load_invalid_value: | |
69 | return "UBSAN: loading invalid value"; | |
70 | #endif | |
71 | #ifdef CONFIG_UBSAN_ALIGNMENT | |
72 | /* | |
73 | * SanitizerKind::Alignment emits SanitizerHandler::TypeMismatch | |
74 | * or SanitizerHandler::AlignmentAssumption. | |
75 | */ | |
76 | case ubsan_alignment_assumption: | |
77 | return "UBSAN: alignment assumption"; | |
78 | case ubsan_type_mismatch: | |
79 | return "UBSAN: type mismatch"; | |
80 | #endif | |
81 | default: | |
82 | return "UBSAN: unrecognized failure code"; | |
83 | } | |
84 | } | |
85 | ||
86 | #else | |
d3c22797 | 87 | static const char * const type_check_kinds[] = { |
c6d30853 AR |
88 | "load of", |
89 | "store to", | |
90 | "reference binding to", | |
91 | "member access within", | |
92 | "member call on", | |
93 | "constructor call on", | |
94 | "downcast of", | |
95 | "downcast of" | |
96 | }; | |
97 | ||
98 | #define REPORTED_BIT 31 | |
99 | ||
100 | #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN) | |
101 | #define COLUMN_MASK (~(1U << REPORTED_BIT)) | |
102 | #define LINE_MASK (~0U) | |
103 | #else | |
104 | #define COLUMN_MASK (~0U) | |
105 | #define LINE_MASK (~(1U << REPORTED_BIT)) | |
106 | #endif | |
107 | ||
108 | #define VALUE_LENGTH 40 | |
109 | ||
110 | static bool was_reported(struct source_location *location) | |
111 | { | |
112 | return test_and_set_bit(REPORTED_BIT, &location->reported); | |
113 | } | |
114 | ||
c6d30853 AR |
115 | static bool suppress_report(struct source_location *loc) |
116 | { | |
117 | return current->in_ubsan || was_reported(loc); | |
118 | } | |
119 | ||
120 | static bool type_is_int(struct type_descriptor *type) | |
121 | { | |
122 | return type->type_kind == type_kind_int; | |
123 | } | |
124 | ||
125 | static bool type_is_signed(struct type_descriptor *type) | |
126 | { | |
127 | WARN_ON(!type_is_int(type)); | |
128 | return type->type_info & 1; | |
129 | } | |
130 | ||
131 | static unsigned type_bit_width(struct type_descriptor *type) | |
132 | { | |
133 | return 1 << (type->type_info >> 1); | |
134 | } | |
135 | ||
136 | static bool is_inline_int(struct type_descriptor *type) | |
137 | { | |
138 | unsigned inline_bits = sizeof(unsigned long)*8; | |
139 | unsigned bits = type_bit_width(type); | |
140 | ||
141 | WARN_ON(!type_is_int(type)); | |
142 | ||
143 | return bits <= inline_bits; | |
144 | } | |
145 | ||
f0996bc2 | 146 | static s_max get_signed_val(struct type_descriptor *type, void *val) |
c6d30853 AR |
147 | { |
148 | if (is_inline_int(type)) { | |
149 | unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type); | |
f0996bc2 AR |
150 | unsigned long ulong_val = (unsigned long)val; |
151 | ||
152 | return ((s_max)ulong_val) << extra_bits >> extra_bits; | |
c6d30853 AR |
153 | } |
154 | ||
155 | if (type_bit_width(type) == 64) | |
156 | return *(s64 *)val; | |
157 | ||
158 | return *(s_max *)val; | |
159 | } | |
160 | ||
f0996bc2 | 161 | static bool val_is_negative(struct type_descriptor *type, void *val) |
c6d30853 AR |
162 | { |
163 | return type_is_signed(type) && get_signed_val(type, val) < 0; | |
164 | } | |
165 | ||
f0996bc2 | 166 | static u_max get_unsigned_val(struct type_descriptor *type, void *val) |
c6d30853 AR |
167 | { |
168 | if (is_inline_int(type)) | |
f0996bc2 | 169 | return (unsigned long)val; |
c6d30853 AR |
170 | |
171 | if (type_bit_width(type) == 64) | |
172 | return *(u64 *)val; | |
173 | ||
174 | return *(u_max *)val; | |
175 | } | |
176 | ||
177 | static void val_to_string(char *str, size_t size, struct type_descriptor *type, | |
f0996bc2 | 178 | void *value) |
c6d30853 AR |
179 | { |
180 | if (type_is_int(type)) { | |
181 | if (type_bit_width(type) == 128) { | |
c12d3362 | 182 | #if defined(CONFIG_ARCH_SUPPORTS_INT128) |
c6d30853 AR |
183 | u_max val = get_unsigned_val(type, value); |
184 | ||
185 | scnprintf(str, size, "0x%08x%08x%08x%08x", | |
186 | (u32)(val >> 96), | |
187 | (u32)(val >> 64), | |
188 | (u32)(val >> 32), | |
189 | (u32)(val)); | |
190 | #else | |
191 | WARN_ON(1); | |
192 | #endif | |
193 | } else if (type_is_signed(type)) { | |
194 | scnprintf(str, size, "%lld", | |
195 | (s64)get_signed_val(type, value)); | |
196 | } else { | |
197 | scnprintf(str, size, "%llu", | |
198 | (u64)get_unsigned_val(type, value)); | |
199 | } | |
200 | } | |
201 | } | |
202 | ||
ef065653 | 203 | static void ubsan_prologue(struct source_location *loc, const char *reason) |
c6d30853 AR |
204 | { |
205 | current->in_ubsan++; | |
c6d30853 | 206 | |
ffda6556 BPA |
207 | pr_warn(CUT_HERE); |
208 | ||
ef065653 KC |
209 | pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name, |
210 | loc->line & LINE_MASK, loc->column & COLUMN_MASK); | |
1195505f UG |
211 | |
212 | kunit_fail_current_test("%s in %s", reason, loc->file_name); | |
c6d30853 AR |
213 | } |
214 | ||
ce5c31db | 215 | static void ubsan_epilogue(void) |
c6d30853 AR |
216 | { |
217 | dump_stack(); | |
ffda6556 | 218 | pr_warn("---[ end trace ]---\n"); |
ce5c31db | 219 | |
c6d30853 | 220 | current->in_ubsan--; |
1d28c8d6 | 221 | |
79cc1ba7 | 222 | check_panic_on_warn("UBSAN"); |
c6d30853 AR |
223 | } |
224 | ||
469cbd01 | 225 | void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs) |
c6d30853 | 226 | { |
469cbd01 | 227 | struct overflow_data *data = _data; |
c6d30853 AR |
228 | char rhs_val_str[VALUE_LENGTH]; |
229 | ||
230 | if (suppress_report(&data->location)) | |
231 | return; | |
232 | ||
ef065653 | 233 | ubsan_prologue(&data->location, "division-overflow"); |
c6d30853 AR |
234 | |
235 | val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs); | |
236 | ||
237 | if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1) | |
238 | pr_err("division of %s by -1 cannot be represented in type %s\n", | |
239 | rhs_val_str, data->type->type_name); | |
240 | else | |
241 | pr_err("division by zero\n"); | |
242 | ||
ce5c31db | 243 | ubsan_epilogue(); |
c6d30853 AR |
244 | } |
245 | EXPORT_SYMBOL(__ubsan_handle_divrem_overflow); | |
246 | ||
42440c1f | 247 | static void handle_null_ptr_deref(struct type_mismatch_data_common *data) |
c6d30853 | 248 | { |
42440c1f | 249 | if (suppress_report(data->location)) |
c6d30853 AR |
250 | return; |
251 | ||
ef065653 | 252 | ubsan_prologue(data->location, "null-ptr-deref"); |
c6d30853 AR |
253 | |
254 | pr_err("%s null pointer of type %s\n", | |
255 | type_check_kinds[data->type_check_kind], | |
256 | data->type->type_name); | |
257 | ||
ce5c31db | 258 | ubsan_epilogue(); |
c6d30853 AR |
259 | } |
260 | ||
42440c1f | 261 | static void handle_misaligned_access(struct type_mismatch_data_common *data, |
c6d30853 AR |
262 | unsigned long ptr) |
263 | { | |
42440c1f | 264 | if (suppress_report(data->location)) |
c6d30853 AR |
265 | return; |
266 | ||
ef065653 | 267 | ubsan_prologue(data->location, "misaligned-access"); |
c6d30853 AR |
268 | |
269 | pr_err("%s misaligned address %p for type %s\n", | |
270 | type_check_kinds[data->type_check_kind], | |
271 | (void *)ptr, data->type->type_name); | |
272 | pr_err("which requires %ld byte alignment\n", data->alignment); | |
273 | ||
ce5c31db | 274 | ubsan_epilogue(); |
c6d30853 AR |
275 | } |
276 | ||
42440c1f | 277 | static void handle_object_size_mismatch(struct type_mismatch_data_common *data, |
c6d30853 AR |
278 | unsigned long ptr) |
279 | { | |
42440c1f | 280 | if (suppress_report(data->location)) |
c6d30853 AR |
281 | return; |
282 | ||
ef065653 | 283 | ubsan_prologue(data->location, "object-size-mismatch"); |
901d805c | 284 | pr_err("%s address %p with insufficient space\n", |
c6d30853 AR |
285 | type_check_kinds[data->type_check_kind], |
286 | (void *) ptr); | |
287 | pr_err("for an object of type %s\n", data->type->type_name); | |
ce5c31db | 288 | ubsan_epilogue(); |
c6d30853 AR |
289 | } |
290 | ||
42440c1f | 291 | static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data, |
c6d30853 AR |
292 | unsigned long ptr) |
293 | { | |
d08965a2 | 294 | unsigned long flags = user_access_save(); |
c6d30853 AR |
295 | |
296 | if (!ptr) | |
297 | handle_null_ptr_deref(data); | |
298 | else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) | |
b8fe1120 | 299 | handle_misaligned_access(data, ptr); |
c6d30853 AR |
300 | else |
301 | handle_object_size_mismatch(data, ptr); | |
d08965a2 PZ |
302 | |
303 | user_access_restore(flags); | |
c6d30853 | 304 | } |
42440c1f AR |
305 | |
306 | void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, | |
f0996bc2 | 307 | void *ptr) |
42440c1f AR |
308 | { |
309 | struct type_mismatch_data_common common_data = { | |
310 | .location = &data->location, | |
311 | .type = data->type, | |
312 | .alignment = data->alignment, | |
313 | .type_check_kind = data->type_check_kind | |
314 | }; | |
315 | ||
f0996bc2 | 316 | ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
42440c1f | 317 | } |
c6d30853 AR |
318 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch); |
319 | ||
469cbd01 | 320 | void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr) |
42440c1f | 321 | { |
469cbd01 | 322 | struct type_mismatch_data_v1 *data = _data; |
42440c1f AR |
323 | struct type_mismatch_data_common common_data = { |
324 | .location = &data->location, | |
325 | .type = data->type, | |
326 | .alignment = 1UL << data->log_alignment, | |
327 | .type_check_kind = data->type_check_kind | |
328 | }; | |
329 | ||
f0996bc2 | 330 | ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
42440c1f AR |
331 | } |
332 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1); | |
333 | ||
469cbd01 | 334 | void __ubsan_handle_out_of_bounds(void *_data, void *index) |
c6d30853 | 335 | { |
469cbd01 | 336 | struct out_of_bounds_data *data = _data; |
c6d30853 AR |
337 | char index_str[VALUE_LENGTH]; |
338 | ||
339 | if (suppress_report(&data->location)) | |
340 | return; | |
341 | ||
ef065653 | 342 | ubsan_prologue(&data->location, "array-index-out-of-bounds"); |
c6d30853 AR |
343 | |
344 | val_to_string(index_str, sizeof(index_str), data->index_type, index); | |
345 | pr_err("index %s is out of range for type %s\n", index_str, | |
346 | data->array_type->type_name); | |
ce5c31db | 347 | ubsan_epilogue(); |
c6d30853 AR |
348 | } |
349 | EXPORT_SYMBOL(__ubsan_handle_out_of_bounds); | |
350 | ||
469cbd01 | 351 | void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs) |
c6d30853 | 352 | { |
469cbd01 | 353 | struct shift_out_of_bounds_data *data = _data; |
c6d30853 AR |
354 | struct type_descriptor *rhs_type = data->rhs_type; |
355 | struct type_descriptor *lhs_type = data->lhs_type; | |
356 | char rhs_str[VALUE_LENGTH]; | |
357 | char lhs_str[VALUE_LENGTH]; | |
9a50dcaf | 358 | unsigned long ua_flags = user_access_save(); |
c6d30853 AR |
359 | |
360 | if (suppress_report(&data->location)) | |
9a50dcaf | 361 | goto out; |
c6d30853 | 362 | |
ef065653 | 363 | ubsan_prologue(&data->location, "shift-out-of-bounds"); |
c6d30853 AR |
364 | |
365 | val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs); | |
366 | val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs); | |
367 | ||
368 | if (val_is_negative(rhs_type, rhs)) | |
369 | pr_err("shift exponent %s is negative\n", rhs_str); | |
370 | ||
371 | else if (get_unsigned_val(rhs_type, rhs) >= | |
372 | type_bit_width(lhs_type)) | |
373 | pr_err("shift exponent %s is too large for %u-bit type %s\n", | |
374 | rhs_str, | |
375 | type_bit_width(lhs_type), | |
376 | lhs_type->type_name); | |
377 | else if (val_is_negative(lhs_type, lhs)) | |
378 | pr_err("left shift of negative value %s\n", | |
379 | lhs_str); | |
380 | else | |
381 | pr_err("left shift of %s by %s places cannot be" | |
382 | " represented in type %s\n", | |
383 | lhs_str, rhs_str, | |
384 | lhs_type->type_name); | |
385 | ||
ce5c31db | 386 | ubsan_epilogue(); |
9a50dcaf PZ |
387 | out: |
388 | user_access_restore(ua_flags); | |
c6d30853 AR |
389 | } |
390 | EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds); | |
391 | ||
392 | ||
469cbd01 | 393 | void __ubsan_handle_builtin_unreachable(void *_data) |
c6d30853 | 394 | { |
469cbd01 | 395 | struct unreachable_data *data = _data; |
ef065653 | 396 | ubsan_prologue(&data->location, "unreachable"); |
c6d30853 | 397 | pr_err("calling __builtin_unreachable()\n"); |
ce5c31db | 398 | ubsan_epilogue(); |
c6d30853 AR |
399 | panic("can't return from __builtin_unreachable()"); |
400 | } | |
401 | EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable); | |
402 | ||
469cbd01 | 403 | void __ubsan_handle_load_invalid_value(void *_data, void *val) |
c6d30853 | 404 | { |
469cbd01 | 405 | struct invalid_value_data *data = _data; |
c6d30853 | 406 | char val_str[VALUE_LENGTH]; |
f18b0d7e | 407 | unsigned long ua_flags = user_access_save(); |
c6d30853 AR |
408 | |
409 | if (suppress_report(&data->location)) | |
f18b0d7e | 410 | goto out; |
c6d30853 | 411 | |
ef065653 | 412 | ubsan_prologue(&data->location, "invalid-load"); |
c6d30853 AR |
413 | |
414 | val_to_string(val_str, sizeof(val_str), data->type, val); | |
415 | ||
416 | pr_err("load of value %s is not a valid value for type %s\n", | |
417 | val_str, data->type->type_name); | |
418 | ||
ce5c31db | 419 | ubsan_epilogue(); |
f18b0d7e PZ |
420 | out: |
421 | user_access_restore(ua_flags); | |
c6d30853 AR |
422 | } |
423 | EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); | |
28abcc96 | 424 | |
28abcc96 NC |
425 | void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, |
426 | unsigned long align, | |
427 | unsigned long offset) | |
428 | { | |
429 | struct alignment_assumption_data *data = _data; | |
430 | unsigned long real_ptr; | |
431 | ||
432 | if (suppress_report(&data->location)) | |
433 | return; | |
434 | ||
435 | ubsan_prologue(&data->location, "alignment-assumption"); | |
436 | ||
437 | if (offset) | |
438 | pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed", | |
439 | align, offset, data->type->type_name); | |
440 | else | |
441 | pr_err("assumption of %lu byte alignment for pointer of type %s failed", | |
442 | align, data->type->type_name); | |
443 | ||
444 | real_ptr = ptr - offset; | |
445 | pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes", | |
446 | offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0), | |
447 | real_ptr & (align - 1)); | |
448 | ||
449 | ubsan_epilogue(); | |
450 | } | |
451 | EXPORT_SYMBOL(__ubsan_handle_alignment_assumption); | |
25b84002 KC |
452 | |
453 | #endif /* !CONFIG_UBSAN_TRAP */ |