projects/linux·blob master · refs

561 lines · 14.1 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * UBSAN error reporting functions
4 *
5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
6 * Author: Andrey Ryabinin <[email protected]>
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>
16#include <linux/uaccess.h>
17#include <linux/ubsan.h>
18#include <kunit/test-bug.h>
19
20#include "ubsan.h"
21
22#if defined(CONFIG_UBSAN_TRAP) || defined(CONFIG_UBSAN_KVM_EL2)
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 */
28const char *report_ubsan_failure(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#if defined(CONFIG_UBSAN_DIV_ZERO) || defined(CONFIG_UBSAN_INTEGER_WRAP)
48 /*
49 * SanitizerKind::IntegerDivideByZero and
50 * SanitizerKind::SignedIntegerOverflow emit
51 * SanitizerHandler::DivremOverflow.
52 */
53 case ubsan_divrem_overflow:
54 return "UBSAN: divide/remainder overflow";
55#endif
56#ifdef CONFIG_UBSAN_UNREACHABLE
57 /*
58 * SanitizerKind::Unreachable emits
59 * SanitizerHandler::BuiltinUnreachable.
60 */
61 case ubsan_builtin_unreachable:
62 return "UBSAN: unreachable code";
63#endif
64#if defined(CONFIG_UBSAN_BOOL) || defined(CONFIG_UBSAN_ENUM)
65 /*
66 * SanitizerKind::Bool and SanitizerKind::Enum emit
67 * SanitizerHandler::LoadInvalidValue.
68 */
69 case ubsan_load_invalid_value:
70 return "UBSAN: loading invalid value";
71#endif
72#ifdef CONFIG_UBSAN_ALIGNMENT
73 /*
74 * SanitizerKind::Alignment emits SanitizerHandler::TypeMismatch
75 * or SanitizerHandler::AlignmentAssumption.
76 */
77 case ubsan_alignment_assumption:
78 return "UBSAN: alignment assumption";
79 case ubsan_type_mismatch:
80 return "UBSAN: type mismatch";
81#endif
82#ifdef CONFIG_UBSAN_INTEGER_WRAP
83 /*
84 * SanitizerKind::SignedIntegerOverflow emits
85 * SanitizerHandler::AddOverflow, SanitizerHandler::SubOverflow,
86 * or SanitizerHandler::MulOverflow.
87 */
88 case ubsan_add_overflow:
89 return "UBSAN: integer addition overflow";
90 case ubsan_sub_overflow:
91 return "UBSAN: integer subtraction overflow";
92 case ubsan_mul_overflow:
93 return "UBSAN: integer multiplication overflow";
94#endif
95 default:
96 return "UBSAN: unrecognized failure code";
97 }
98}
99
100#endif
101
102#ifndef CONFIG_UBSAN_TRAP
103static const char * const type_check_kinds[] = {
104 "load of",
105 "store to",
106 "reference binding to",
107 "member access within",
108 "member call on",
109 "constructor call on",
110 "downcast of",
111 "downcast of"
112};
113
114#define REPORTED_BIT 31
115
116#if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)
117#define COLUMN_MASK (~(1U << REPORTED_BIT))
118#define LINE_MASK (~0U)
119#else
120#define COLUMN_MASK (~0U)
121#define LINE_MASK (~(1U << REPORTED_BIT))
122#endif
123
124#define VALUE_LENGTH 40
125
126static bool was_reported(struct source_location *location)
127{
128 return test_and_set_bit(REPORTED_BIT, &location->reported);
129}
130
131static bool suppress_report(struct source_location *loc)
132{
133 return current->in_ubsan || was_reported(loc);
134}
135
136static bool type_is_int(struct type_descriptor *type)
137{
138 return type->type_kind == type_kind_int;
139}
140
141static bool type_is_signed(struct type_descriptor *type)
142{
143 WARN_ON(!type_is_int(type));
144 return type->type_info & 1;
145}
146
147static unsigned type_bit_width(struct type_descriptor *type)
148{
149 return 1 << (type->type_info >> 1);
150}
151
152static bool is_inline_int(struct type_descriptor *type)
153{
154 unsigned inline_bits = sizeof(unsigned long)*8;
155 unsigned bits = type_bit_width(type);
156
157 WARN_ON(!type_is_int(type));
158
159 return bits <= inline_bits;
160}
161
162static s_max get_signed_val(struct type_descriptor *type, void *val)
163{
164 if (is_inline_int(type)) {
165 unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type);
166 unsigned long ulong_val = (unsigned long)val;
167
168 return ((s_max)ulong_val) << extra_bits >> extra_bits;
169 }
170
171 if (type_bit_width(type) == 64)
172 return *(s64 *)val;
173
174 return *(s_max *)val;
175}
176
177static bool val_is_negative(struct type_descriptor *type, void *val)
178{
179 return type_is_signed(type) && get_signed_val(type, val) < 0;
180}
181
182static u_max get_unsigned_val(struct type_descriptor *type, void *val)
183{
184 if (is_inline_int(type))
185 return (unsigned long)val;
186
187 if (type_bit_width(type) == 64)
188 return *(u64 *)val;
189
190 return *(u_max *)val;
191}
192
193static void val_to_string(char *str, size_t size, struct type_descriptor *type,
194 void *value)
195{
196 if (type_is_int(type)) {
197 if (type_bit_width(type) == 128) {
198#if defined(CONFIG_ARCH_SUPPORTS_INT128)
199 u_max val = get_unsigned_val(type, value);
200
201 scnprintf(str, size, "0x%08x%08x%08x%08x",
202 (u32)(val >> 96),
203 (u32)(val >> 64),
204 (u32)(val >> 32),
205 (u32)(val));
206#else
207 WARN_ON(1);
208#endif
209 } else if (type_is_signed(type)) {
210 scnprintf(str, size, "%lld",
211 (s64)get_signed_val(type, value));
212 } else {
213 scnprintf(str, size, "%llu",
214 (u64)get_unsigned_val(type, value));
215 }
216 }
217}
218
219static void ubsan_prologue(struct source_location *loc, const char *reason)
220{
221 current->in_ubsan++;
222
223 pr_warn(CUT_HERE);
224
225 pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name,
226 loc->line & LINE_MASK, loc->column & COLUMN_MASK);
227
228 kunit_fail_current_test("%s in %s", reason, loc->file_name);
229}
230
231static void ubsan_epilogue(void)
232{
233 dump_stack();
234 pr_warn("---[ end trace ]---\n");
235
236 current->in_ubsan--;
237
238 check_panic_on_warn("UBSAN");
239}
240
241static void handle_overflow(struct overflow_data *data, void *lhs,
242 void *rhs, char op)
243{
244
245 struct type_descriptor *type = data->type;
246 char lhs_val_str[VALUE_LENGTH];
247 char rhs_val_str[VALUE_LENGTH];
248
249 if (suppress_report(&data->location))
250 return;
251
252 ubsan_prologue(&data->location, type_is_signed(type) ?
253 "signed-integer-overflow" :
254 "unsigned-integer-overflow");
255
256 val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);
257 val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);
258 pr_err("%s %c %s cannot be represented in type %s\n",
259 lhs_val_str,
260 op,
261 rhs_val_str,
262 type->type_name);
263
264 ubsan_epilogue();
265}
266
267void __ubsan_handle_add_overflow(void *data,
268 void *lhs, void *rhs)
269{
270
271 handle_overflow(data, lhs, rhs, '+');
272}
273EXPORT_SYMBOL(__ubsan_handle_add_overflow);
274
275void __ubsan_handle_sub_overflow(void *data,
276 void *lhs, void *rhs)
277{
278 handle_overflow(data, lhs, rhs, '-');
279}
280EXPORT_SYMBOL(__ubsan_handle_sub_overflow);
281
282void __ubsan_handle_mul_overflow(void *data,
283 void *lhs, void *rhs)
284{
285 handle_overflow(data, lhs, rhs, '*');
286}
287EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
288
289void __ubsan_handle_negate_overflow(void *_data, void *old_val)
290{
291 struct overflow_data *data = _data;
292 char old_val_str[VALUE_LENGTH];
293
294 if (suppress_report(&data->location))
295 return;
296
297 ubsan_prologue(&data->location, "negation-overflow");
298
299 val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val);
300
301 pr_err("negation of %s cannot be represented in type %s:\n",
302 old_val_str, data->type->type_name);
303
304 ubsan_epilogue();
305}
306EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
307
308void __ubsan_handle_implicit_conversion(void *_data, void *from_val, void *to_val)
309{
310 struct implicit_conversion_data *data = _data;
311 char from_val_str[VALUE_LENGTH];
312 char to_val_str[VALUE_LENGTH];
313
314 if (suppress_report(&data->location))
315 return;
316
317 val_to_string(from_val_str, sizeof(from_val_str), data->from_type, from_val);
318 val_to_string(to_val_str, sizeof(to_val_str), data->to_type, to_val);
319
320 ubsan_prologue(&data->location, "implicit-conversion");
321
322 pr_err("cannot represent %s value %s during %s %s, truncated to %s\n",
323 data->from_type->type_name,
324 from_val_str,
325 type_check_kinds[data->type_check_kind],
326 data->to_type->type_name,
327 to_val_str);
328
329 ubsan_epilogue();
330}
331EXPORT_SYMBOL(__ubsan_handle_implicit_conversion);
332
333void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)
334{
335 struct overflow_data *data = _data;
336 char lhs_val_str[VALUE_LENGTH];
337
338 if (suppress_report(&data->location))
339 return;
340
341 ubsan_prologue(&data->location, "division-overflow");
342
343 val_to_string(lhs_val_str, sizeof(lhs_val_str), data->type, lhs);
344
345 if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1)
346 pr_err("division of %s by -1 cannot be represented in type %s\n",
347 lhs_val_str, data->type->type_name);
348 else
349 pr_err("division by zero\n");
350
351 ubsan_epilogue();
352}
353EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
354
355static void handle_null_ptr_deref(struct type_mismatch_data_common *data)
356{
357 if (suppress_report(data->location))
358 return;
359
360 ubsan_prologue(data->location, "null-ptr-deref");
361
362 pr_err("%s null pointer of type %s\n",
363 type_check_kinds[data->type_check_kind],
364 data->type->type_name);
365
366 ubsan_epilogue();
367}
368
369static void handle_misaligned_access(struct type_mismatch_data_common *data,
370 unsigned long ptr)
371{
372 if (suppress_report(data->location))
373 return;
374
375 ubsan_prologue(data->location, "misaligned-access");
376
377 pr_err("%s misaligned address %p for type %s\n",
378 type_check_kinds[data->type_check_kind],
379 (void *)ptr, data->type->type_name);
380 pr_err("which requires %ld byte alignment\n", data->alignment);
381
382 ubsan_epilogue();
383}
384
385static void handle_object_size_mismatch(struct type_mismatch_data_common *data,
386 unsigned long ptr)
387{
388 if (suppress_report(data->location))
389 return;
390
391 ubsan_prologue(data->location, "object-size-mismatch");
392 pr_err("%s address %p with insufficient space\n",
393 type_check_kinds[data->type_check_kind],
394 (void *) ptr);
395 pr_err("for an object of type %s\n", data->type->type_name);
396 ubsan_epilogue();
397}
398
399static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
400 unsigned long ptr)
401{
402 unsigned long flags = user_access_save();
403
404 if (!ptr)
405 handle_null_ptr_deref(data);
406 else if (data->alignment && !IS_ALIGNED(ptr, data->alignment))
407 handle_misaligned_access(data, ptr);
408 else
409 handle_object_size_mismatch(data, ptr);
410
411 user_access_restore(flags);
412}
413
414void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
415 void *ptr)
416{
417 struct type_mismatch_data_common common_data = {
418 .location = &data->location,
419 .type = data->type,
420 .alignment = data->alignment,
421 .type_check_kind = data->type_check_kind
422 };
423
424 ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
425}
426EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
427
428void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr)
429{
430 struct type_mismatch_data_v1 *data = _data;
431 struct type_mismatch_data_common common_data = {
432 .location = &data->location,
433 .type = data->type,
434 .alignment = 1UL << data->log_alignment,
435 .type_check_kind = data->type_check_kind
436 };
437
438 ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
439}
440EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
441
442void __ubsan_handle_out_of_bounds(void *_data, void *index)
443{
444 struct out_of_bounds_data *data = _data;
445 char index_str[VALUE_LENGTH];
446
447 if (suppress_report(&data->location))
448 return;
449
450 ubsan_prologue(&data->location, "array-index-out-of-bounds");
451
452 val_to_string(index_str, sizeof(index_str), data->index_type, index);
453 pr_err("index %s is out of range for type %s\n", index_str,
454 data->array_type->type_name);
455 ubsan_epilogue();
456}
457EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
458
459void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs)
460{
461 struct shift_out_of_bounds_data *data = _data;
462 struct type_descriptor *rhs_type = data->rhs_type;
463 struct type_descriptor *lhs_type = data->lhs_type;
464 char rhs_str[VALUE_LENGTH];
465 char lhs_str[VALUE_LENGTH];
466 unsigned long ua_flags = user_access_save();
467
468 if (suppress_report(&data->location))
469 goto out;
470
471 ubsan_prologue(&data->location, "shift-out-of-bounds");
472
473 val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);
474 val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs);
475
476 if (val_is_negative(rhs_type, rhs))
477 pr_err("shift exponent %s is negative\n", rhs_str);
478
479 else if (get_unsigned_val(rhs_type, rhs) >=
480 type_bit_width(lhs_type))
481 pr_err("shift exponent %s is too large for %u-bit type %s\n",
482 rhs_str,
483 type_bit_width(lhs_type),
484 lhs_type->type_name);
485 else if (val_is_negative(lhs_type, lhs))
486 pr_err("left shift of negative value %s\n",
487 lhs_str);
488 else
489 pr_err("left shift of %s by %s places cannot be"
490 " represented in type %s\n",
491 lhs_str, rhs_str,
492 lhs_type->type_name);
493
494 ubsan_epilogue();
495out:
496 user_access_restore(ua_flags);
497}
498EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
499
500
501void __ubsan_handle_builtin_unreachable(void *_data)
502{
503 struct unreachable_data *data = _data;
504 ubsan_prologue(&data->location, "unreachable");
505 pr_err("calling __builtin_unreachable()\n");
506 ubsan_epilogue();
507 panic("can't return from __builtin_unreachable()");
508}
509EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
510
511void __ubsan_handle_load_invalid_value(void *_data, void *val)
512{
513 struct invalid_value_data *data = _data;
514 char val_str[VALUE_LENGTH];
515 unsigned long ua_flags = user_access_save();
516
517 if (suppress_report(&data->location))
518 goto out;
519
520 ubsan_prologue(&data->location, "invalid-load");
521
522 val_to_string(val_str, sizeof(val_str), data->type, val);
523
524 pr_err("load of value %s is not a valid value for type %s\n",
525 val_str, data->type->type_name);
526
527 ubsan_epilogue();
528out:
529 user_access_restore(ua_flags);
530}
531EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
532
533void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr,
534 unsigned long align,
535 unsigned long offset)
536{
537 struct alignment_assumption_data *data = _data;
538 unsigned long real_ptr;
539
540 if (suppress_report(&data->location))
541 return;
542
543 ubsan_prologue(&data->location, "alignment-assumption");
544
545 if (offset)
546 pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed",
547 align, offset, data->type->type_name);
548 else
549 pr_err("assumption of %lu byte alignment for pointer of type %s failed",
550 align, data->type->type_name);
551
552 real_ptr = ptr - offset;
553 pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes",
554 offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0),
555 real_ptr & (align - 1));
556
557 ubsan_epilogue();
558}
559EXPORT_SYMBOL(__ubsan_handle_alignment_assumption);
560
561#endif /* !CONFIG_UBSAN_TRAP */