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Andrey Ryabininc6d30852016-01-20 15:00:55 -08001/*
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
23const 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
46static bool was_reported(struct source_location *location)
47{
48 return test_and_set_bit(REPORTED_BIT, &location->reported);
49}
50
51static 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
58static bool suppress_report(struct source_location *loc)
59{
60 return current->in_ubsan || was_reported(loc);
61}
62
63static bool type_is_int(struct type_descriptor *type)
64{
65 return type->type_kind == type_kind_int;
66}
67
68static bool type_is_signed(struct type_descriptor *type)
69{
70 WARN_ON(!type_is_int(type));
71 return type->type_info & 1;
72}
73
74static unsigned type_bit_width(struct type_descriptor *type)
75{
76 return 1 << (type->type_info >> 1);
77}
78
79static 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
Andrey Ryabininb34d6552019-05-06 13:45:26 +030089static s_max get_signed_val(struct type_descriptor *type, void *val)
Andrey Ryabininc6d30852016-01-20 15:00:55 -080090{
91 if (is_inline_int(type)) {
92 unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type);
Andrey Ryabininb34d6552019-05-06 13:45:26 +030093 unsigned long ulong_val = (unsigned long)val;
94
95 return ((s_max)ulong_val) << extra_bits >> extra_bits;
Andrey Ryabininc6d30852016-01-20 15:00:55 -080096 }
97
98 if (type_bit_width(type) == 64)
99 return *(s64 *)val;
100
101 return *(s_max *)val;
102}
103
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300104static bool val_is_negative(struct type_descriptor *type, void *val)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800105{
106 return type_is_signed(type) && get_signed_val(type, val) < 0;
107}
108
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300109static u_max get_unsigned_val(struct type_descriptor *type, void *val)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800110{
111 if (is_inline_int(type))
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300112 return (unsigned long)val;
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800113
114 if (type_bit_width(type) == 64)
115 return *(u64 *)val;
116
117 return *(u_max *)val;
118}
119
120static void val_to_string(char *str, size_t size, struct type_descriptor *type,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300121 void *value)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800122{
123 if (type_is_int(type)) {
124 if (type_bit_width(type) == 128) {
125#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__)
126 u_max val = get_unsigned_val(type, value);
127
128 scnprintf(str, size, "0x%08x%08x%08x%08x",
129 (u32)(val >> 96),
130 (u32)(val >> 64),
131 (u32)(val >> 32),
132 (u32)(val));
133#else
134 WARN_ON(1);
135#endif
136 } else if (type_is_signed(type)) {
137 scnprintf(str, size, "%lld",
138 (s64)get_signed_val(type, value));
139 } else {
140 scnprintf(str, size, "%llu",
141 (u64)get_unsigned_val(type, value));
142 }
143 }
144}
145
146static bool location_is_valid(struct source_location *loc)
147{
148 return loc->file_name != NULL;
149}
150
151static DEFINE_SPINLOCK(report_lock);
152
153static void ubsan_prologue(struct source_location *location,
154 unsigned long *flags)
155{
156 current->in_ubsan++;
157 spin_lock_irqsave(&report_lock, *flags);
158
159 pr_err("========================================"
160 "========================================\n");
161 print_source_location("UBSAN: Undefined behaviour in", location);
162}
163
164static void ubsan_epilogue(unsigned long *flags)
165{
166 dump_stack();
167 pr_err("========================================"
168 "========================================\n");
169 spin_unlock_irqrestore(&report_lock, *flags);
170 current->in_ubsan--;
171}
172
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300173static void handle_overflow(struct overflow_data *data, void *lhs,
174 void *rhs, char op)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800175{
176
177 struct type_descriptor *type = data->type;
178 unsigned long flags;
179 char lhs_val_str[VALUE_LENGTH];
180 char rhs_val_str[VALUE_LENGTH];
181
182 if (suppress_report(&data->location))
183 return;
184
185 ubsan_prologue(&data->location, &flags);
186
187 val_to_string(lhs_val_str, sizeof(lhs_val_str), type, lhs);
188 val_to_string(rhs_val_str, sizeof(rhs_val_str), type, rhs);
189 pr_err("%s integer overflow:\n",
190 type_is_signed(type) ? "signed" : "unsigned");
191 pr_err("%s %c %s cannot be represented in type %s\n",
192 lhs_val_str,
193 op,
194 rhs_val_str,
195 type->type_name);
196
197 ubsan_epilogue(&flags);
198}
199
200void __ubsan_handle_add_overflow(struct overflow_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300201 void *lhs, void *rhs)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800202{
203
204 handle_overflow(data, lhs, rhs, '+');
205}
206EXPORT_SYMBOL(__ubsan_handle_add_overflow);
207
208void __ubsan_handle_sub_overflow(struct overflow_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300209 void *lhs, void *rhs)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800210{
211 handle_overflow(data, lhs, rhs, '-');
212}
213EXPORT_SYMBOL(__ubsan_handle_sub_overflow);
214
215void __ubsan_handle_mul_overflow(struct overflow_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300216 void *lhs, void *rhs)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800217{
218 handle_overflow(data, lhs, rhs, '*');
219}
220EXPORT_SYMBOL(__ubsan_handle_mul_overflow);
221
222void __ubsan_handle_negate_overflow(struct overflow_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300223 void *old_val)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800224{
225 unsigned long flags;
226 char old_val_str[VALUE_LENGTH];
227
228 if (suppress_report(&data->location))
229 return;
230
231 ubsan_prologue(&data->location, &flags);
232
233 val_to_string(old_val_str, sizeof(old_val_str), data->type, old_val);
234
235 pr_err("negation of %s cannot be represented in type %s:\n",
236 old_val_str, data->type->type_name);
237
238 ubsan_epilogue(&flags);
239}
240EXPORT_SYMBOL(__ubsan_handle_negate_overflow);
241
242
243void __ubsan_handle_divrem_overflow(struct overflow_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300244 void *lhs, void *rhs)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800245{
246 unsigned long flags;
247 char rhs_val_str[VALUE_LENGTH];
248
249 if (suppress_report(&data->location))
250 return;
251
252 ubsan_prologue(&data->location, &flags);
253
254 val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs);
255
256 if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1)
257 pr_err("division of %s by -1 cannot be represented in type %s\n",
258 rhs_val_str, data->type->type_name);
259 else
260 pr_err("division by zero\n");
261
262 ubsan_epilogue(&flags);
263}
264EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
265
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800266static void handle_null_ptr_deref(struct type_mismatch_data_common *data)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800267{
268 unsigned long flags;
269
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800270 if (suppress_report(data->location))
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800271 return;
272
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800273 ubsan_prologue(data->location, &flags);
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800274
275 pr_err("%s null pointer of type %s\n",
276 type_check_kinds[data->type_check_kind],
277 data->type->type_name);
278
279 ubsan_epilogue(&flags);
280}
281
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800282static void handle_misaligned_access(struct type_mismatch_data_common *data,
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800283 unsigned long ptr)
284{
285 unsigned long flags;
286
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800287 if (suppress_report(data->location))
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800288 return;
289
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800290 ubsan_prologue(data->location, &flags);
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800291
292 pr_err("%s misaligned address %p for type %s\n",
293 type_check_kinds[data->type_check_kind],
294 (void *)ptr, data->type->type_name);
295 pr_err("which requires %ld byte alignment\n", data->alignment);
296
297 ubsan_epilogue(&flags);
298}
299
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800300static void handle_object_size_mismatch(struct type_mismatch_data_common *data,
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800301 unsigned long ptr)
302{
303 unsigned long flags;
304
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800305 if (suppress_report(data->location))
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800306 return;
307
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800308 ubsan_prologue(data->location, &flags);
Nicolas Iooss901d8052016-08-02 14:03:10 -0700309 pr_err("%s address %p with insufficient space\n",
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800310 type_check_kinds[data->type_check_kind],
311 (void *) ptr);
312 pr_err("for an object of type %s\n", data->type->type_name);
313 ubsan_epilogue(&flags);
314}
315
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800316static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800317 unsigned long ptr)
318{
319
320 if (!ptr)
321 handle_null_ptr_deref(data);
322 else if (data->alignment && !IS_ALIGNED(ptr, data->alignment))
Andrew Morton3f813012018-02-06 15:40:38 -0800323 handle_misaligned_access(data, ptr);
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800324 else
325 handle_object_size_mismatch(data, ptr);
326}
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800327
328void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300329 void *ptr)
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800330{
331 struct type_mismatch_data_common common_data = {
332 .location = &data->location,
333 .type = data->type,
334 .alignment = data->alignment,
335 .type_check_kind = data->type_check_kind
336 };
337
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300338 ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800339}
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800340EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
341
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800342void __ubsan_handle_type_mismatch_v1(struct type_mismatch_data_v1 *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300343 void *ptr)
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800344{
345
346 struct type_mismatch_data_common common_data = {
347 .location = &data->location,
348 .type = data->type,
349 .alignment = 1UL << data->log_alignment,
350 .type_check_kind = data->type_check_kind
351 };
352
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300353 ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
Andrey Ryabinin3c83fe52018-02-06 15:40:42 -0800354}
355EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
356
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800357void __ubsan_handle_nonnull_return(struct nonnull_return_data *data)
358{
359 unsigned long flags;
360
361 if (suppress_report(&data->location))
362 return;
363
364 ubsan_prologue(&data->location, &flags);
365
366 pr_err("null pointer returned from function declared to never return null\n");
367
368 if (location_is_valid(&data->attr_location))
369 print_source_location("returns_nonnull attribute specified in",
370 &data->attr_location);
371
372 ubsan_epilogue(&flags);
373}
374EXPORT_SYMBOL(__ubsan_handle_nonnull_return);
375
376void __ubsan_handle_vla_bound_not_positive(struct vla_bound_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300377 void *bound)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800378{
379 unsigned long flags;
380 char bound_str[VALUE_LENGTH];
381
382 if (suppress_report(&data->location))
383 return;
384
385 ubsan_prologue(&data->location, &flags);
386
387 val_to_string(bound_str, sizeof(bound_str), data->type, bound);
388 pr_err("variable length array bound value %s <= 0\n", bound_str);
389
390 ubsan_epilogue(&flags);
391}
392EXPORT_SYMBOL(__ubsan_handle_vla_bound_not_positive);
393
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300394void __ubsan_handle_out_of_bounds(struct out_of_bounds_data *data, void *index)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800395{
396 unsigned long flags;
397 char index_str[VALUE_LENGTH];
398
399 if (suppress_report(&data->location))
400 return;
401
402 ubsan_prologue(&data->location, &flags);
403
404 val_to_string(index_str, sizeof(index_str), data->index_type, index);
405 pr_err("index %s is out of range for type %s\n", index_str,
406 data->array_type->type_name);
407 ubsan_epilogue(&flags);
408}
409EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
410
411void __ubsan_handle_shift_out_of_bounds(struct shift_out_of_bounds_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300412 void *lhs, void *rhs)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800413{
414 unsigned long flags;
415 struct type_descriptor *rhs_type = data->rhs_type;
416 struct type_descriptor *lhs_type = data->lhs_type;
417 char rhs_str[VALUE_LENGTH];
418 char lhs_str[VALUE_LENGTH];
419
420 if (suppress_report(&data->location))
421 return;
422
423 ubsan_prologue(&data->location, &flags);
424
425 val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs);
426 val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs);
427
428 if (val_is_negative(rhs_type, rhs))
429 pr_err("shift exponent %s is negative\n", rhs_str);
430
431 else if (get_unsigned_val(rhs_type, rhs) >=
432 type_bit_width(lhs_type))
433 pr_err("shift exponent %s is too large for %u-bit type %s\n",
434 rhs_str,
435 type_bit_width(lhs_type),
436 lhs_type->type_name);
437 else if (val_is_negative(lhs_type, lhs))
438 pr_err("left shift of negative value %s\n",
439 lhs_str);
440 else
441 pr_err("left shift of %s by %s places cannot be"
442 " represented in type %s\n",
443 lhs_str, rhs_str,
444 lhs_type->type_name);
445
446 ubsan_epilogue(&flags);
447}
448EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
449
450
Arnd Bergmanne133c332018-11-16 15:08:35 -0800451void __ubsan_handle_builtin_unreachable(struct unreachable_data *data)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800452{
453 unsigned long flags;
454
455 ubsan_prologue(&data->location, &flags);
456 pr_err("calling __builtin_unreachable()\n");
457 ubsan_epilogue(&flags);
458 panic("can't return from __builtin_unreachable()");
459}
460EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
461
462void __ubsan_handle_load_invalid_value(struct invalid_value_data *data,
Andrey Ryabininb34d6552019-05-06 13:45:26 +0300463 void *val)
Andrey Ryabininc6d30852016-01-20 15:00:55 -0800464{
465 unsigned long flags;
466 char val_str[VALUE_LENGTH];
467
468 if (suppress_report(&data->location))
469 return;
470
471 ubsan_prologue(&data->location, &flags);
472
473 val_to_string(val_str, sizeof(val_str), data->type, val);
474
475 pr_err("load of value %s is not a valid value for type %s\n",
476 val_str, data->type->type_name);
477
478 ubsan_epilogue(&flags);
479}
480EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);