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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 <[email protected]> | |
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> |
1195505f | 17 | #include <kunit/test-bug.h> |
c6d30853 AR |
18 | |
19 | #include "ubsan.h" | |
20 | ||
d3c22797 | 21 | static const char * const type_check_kinds[] = { |
c6d30853 AR |
22 | "load of", |
23 | "store to", | |
24 | "reference binding to", | |
25 | "member access within", | |
26 | "member call on", | |
27 | "constructor call on", | |
28 | "downcast of", | |
29 | "downcast of" | |
30 | }; | |
31 | ||
32 | #define REPORTED_BIT 31 | |
33 | ||
34 | #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN) | |
35 | #define COLUMN_MASK (~(1U << REPORTED_BIT)) | |
36 | #define LINE_MASK (~0U) | |
37 | #else | |
38 | #define COLUMN_MASK (~0U) | |
39 | #define LINE_MASK (~(1U << REPORTED_BIT)) | |
40 | #endif | |
41 | ||
42 | #define VALUE_LENGTH 40 | |
43 | ||
44 | static bool was_reported(struct source_location *location) | |
45 | { | |
46 | return test_and_set_bit(REPORTED_BIT, &location->reported); | |
47 | } | |
48 | ||
c6d30853 AR |
49 | static bool suppress_report(struct source_location *loc) |
50 | { | |
51 | return current->in_ubsan || was_reported(loc); | |
52 | } | |
53 | ||
54 | static bool type_is_int(struct type_descriptor *type) | |
55 | { | |
56 | return type->type_kind == type_kind_int; | |
57 | } | |
58 | ||
59 | static bool type_is_signed(struct type_descriptor *type) | |
60 | { | |
61 | WARN_ON(!type_is_int(type)); | |
62 | return type->type_info & 1; | |
63 | } | |
64 | ||
65 | static unsigned type_bit_width(struct type_descriptor *type) | |
66 | { | |
67 | return 1 << (type->type_info >> 1); | |
68 | } | |
69 | ||
70 | static bool is_inline_int(struct type_descriptor *type) | |
71 | { | |
72 | unsigned inline_bits = sizeof(unsigned long)*8; | |
73 | unsigned bits = type_bit_width(type); | |
74 | ||
75 | WARN_ON(!type_is_int(type)); | |
76 | ||
77 | return bits <= inline_bits; | |
78 | } | |
79 | ||
f0996bc2 | 80 | static s_max get_signed_val(struct type_descriptor *type, void *val) |
c6d30853 AR |
81 | { |
82 | if (is_inline_int(type)) { | |
83 | unsigned extra_bits = sizeof(s_max)*8 - type_bit_width(type); | |
f0996bc2 AR |
84 | unsigned long ulong_val = (unsigned long)val; |
85 | ||
86 | return ((s_max)ulong_val) << extra_bits >> extra_bits; | |
c6d30853 AR |
87 | } |
88 | ||
89 | if (type_bit_width(type) == 64) | |
90 | return *(s64 *)val; | |
91 | ||
92 | return *(s_max *)val; | |
93 | } | |
94 | ||
f0996bc2 | 95 | static bool val_is_negative(struct type_descriptor *type, void *val) |
c6d30853 AR |
96 | { |
97 | return type_is_signed(type) && get_signed_val(type, val) < 0; | |
98 | } | |
99 | ||
f0996bc2 | 100 | static u_max get_unsigned_val(struct type_descriptor *type, void *val) |
c6d30853 AR |
101 | { |
102 | if (is_inline_int(type)) | |
f0996bc2 | 103 | return (unsigned long)val; |
c6d30853 AR |
104 | |
105 | if (type_bit_width(type) == 64) | |
106 | return *(u64 *)val; | |
107 | ||
108 | return *(u_max *)val; | |
109 | } | |
110 | ||
111 | static void val_to_string(char *str, size_t size, struct type_descriptor *type, | |
f0996bc2 | 112 | void *value) |
c6d30853 AR |
113 | { |
114 | if (type_is_int(type)) { | |
115 | if (type_bit_width(type) == 128) { | |
c12d3362 | 116 | #if defined(CONFIG_ARCH_SUPPORTS_INT128) |
c6d30853 AR |
117 | u_max val = get_unsigned_val(type, value); |
118 | ||
119 | scnprintf(str, size, "0x%08x%08x%08x%08x", | |
120 | (u32)(val >> 96), | |
121 | (u32)(val >> 64), | |
122 | (u32)(val >> 32), | |
123 | (u32)(val)); | |
124 | #else | |
125 | WARN_ON(1); | |
126 | #endif | |
127 | } else if (type_is_signed(type)) { | |
128 | scnprintf(str, size, "%lld", | |
129 | (s64)get_signed_val(type, value)); | |
130 | } else { | |
131 | scnprintf(str, size, "%llu", | |
132 | (u64)get_unsigned_val(type, value)); | |
133 | } | |
134 | } | |
135 | } | |
136 | ||
ef065653 | 137 | static void ubsan_prologue(struct source_location *loc, const char *reason) |
c6d30853 AR |
138 | { |
139 | current->in_ubsan++; | |
c6d30853 AR |
140 | |
141 | pr_err("========================================" | |
142 | "========================================\n"); | |
ef065653 KC |
143 | pr_err("UBSAN: %s in %s:%d:%d\n", reason, loc->file_name, |
144 | loc->line & LINE_MASK, loc->column & COLUMN_MASK); | |
1195505f UG |
145 | |
146 | kunit_fail_current_test("%s in %s", reason, loc->file_name); | |
c6d30853 AR |
147 | } |
148 | ||
ce5c31db | 149 | static void ubsan_epilogue(void) |
c6d30853 AR |
150 | { |
151 | dump_stack(); | |
152 | pr_err("========================================" | |
153 | "========================================\n"); | |
ce5c31db | 154 | |
c6d30853 | 155 | current->in_ubsan--; |
1d28c8d6 | 156 | |
d83ce027 | 157 | if (panic_on_warn) |
1d28c8d6 | 158 | panic("panic_on_warn set ...\n"); |
c6d30853 AR |
159 | } |
160 | ||
469cbd01 | 161 | void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs) |
c6d30853 | 162 | { |
469cbd01 | 163 | struct overflow_data *data = _data; |
c6d30853 AR |
164 | char rhs_val_str[VALUE_LENGTH]; |
165 | ||
166 | if (suppress_report(&data->location)) | |
167 | return; | |
168 | ||
ef065653 | 169 | ubsan_prologue(&data->location, "division-overflow"); |
c6d30853 AR |
170 | |
171 | val_to_string(rhs_val_str, sizeof(rhs_val_str), data->type, rhs); | |
172 | ||
173 | if (type_is_signed(data->type) && get_signed_val(data->type, rhs) == -1) | |
174 | pr_err("division of %s by -1 cannot be represented in type %s\n", | |
175 | rhs_val_str, data->type->type_name); | |
176 | else | |
177 | pr_err("division by zero\n"); | |
178 | ||
ce5c31db | 179 | ubsan_epilogue(); |
c6d30853 AR |
180 | } |
181 | EXPORT_SYMBOL(__ubsan_handle_divrem_overflow); | |
182 | ||
42440c1f | 183 | static void handle_null_ptr_deref(struct type_mismatch_data_common *data) |
c6d30853 | 184 | { |
42440c1f | 185 | if (suppress_report(data->location)) |
c6d30853 AR |
186 | return; |
187 | ||
ef065653 | 188 | ubsan_prologue(data->location, "null-ptr-deref"); |
c6d30853 AR |
189 | |
190 | pr_err("%s null pointer of type %s\n", | |
191 | type_check_kinds[data->type_check_kind], | |
192 | data->type->type_name); | |
193 | ||
ce5c31db | 194 | ubsan_epilogue(); |
c6d30853 AR |
195 | } |
196 | ||
42440c1f | 197 | static void handle_misaligned_access(struct type_mismatch_data_common *data, |
c6d30853 AR |
198 | unsigned long ptr) |
199 | { | |
42440c1f | 200 | if (suppress_report(data->location)) |
c6d30853 AR |
201 | return; |
202 | ||
ef065653 | 203 | ubsan_prologue(data->location, "misaligned-access"); |
c6d30853 AR |
204 | |
205 | pr_err("%s misaligned address %p for type %s\n", | |
206 | type_check_kinds[data->type_check_kind], | |
207 | (void *)ptr, data->type->type_name); | |
208 | pr_err("which requires %ld byte alignment\n", data->alignment); | |
209 | ||
ce5c31db | 210 | ubsan_epilogue(); |
c6d30853 AR |
211 | } |
212 | ||
42440c1f | 213 | static void handle_object_size_mismatch(struct type_mismatch_data_common *data, |
c6d30853 AR |
214 | unsigned long ptr) |
215 | { | |
42440c1f | 216 | if (suppress_report(data->location)) |
c6d30853 AR |
217 | return; |
218 | ||
ef065653 | 219 | ubsan_prologue(data->location, "object-size-mismatch"); |
901d805c | 220 | pr_err("%s address %p with insufficient space\n", |
c6d30853 AR |
221 | type_check_kinds[data->type_check_kind], |
222 | (void *) ptr); | |
223 | pr_err("for an object of type %s\n", data->type->type_name); | |
ce5c31db | 224 | ubsan_epilogue(); |
c6d30853 AR |
225 | } |
226 | ||
42440c1f | 227 | static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data, |
c6d30853 AR |
228 | unsigned long ptr) |
229 | { | |
d08965a2 | 230 | unsigned long flags = user_access_save(); |
c6d30853 AR |
231 | |
232 | if (!ptr) | |
233 | handle_null_ptr_deref(data); | |
234 | else if (data->alignment && !IS_ALIGNED(ptr, data->alignment)) | |
b8fe1120 | 235 | handle_misaligned_access(data, ptr); |
c6d30853 AR |
236 | else |
237 | handle_object_size_mismatch(data, ptr); | |
d08965a2 PZ |
238 | |
239 | user_access_restore(flags); | |
c6d30853 | 240 | } |
42440c1f AR |
241 | |
242 | void __ubsan_handle_type_mismatch(struct type_mismatch_data *data, | |
f0996bc2 | 243 | void *ptr) |
42440c1f AR |
244 | { |
245 | struct type_mismatch_data_common common_data = { | |
246 | .location = &data->location, | |
247 | .type = data->type, | |
248 | .alignment = data->alignment, | |
249 | .type_check_kind = data->type_check_kind | |
250 | }; | |
251 | ||
f0996bc2 | 252 | ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
42440c1f | 253 | } |
c6d30853 AR |
254 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch); |
255 | ||
469cbd01 | 256 | void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr) |
42440c1f | 257 | { |
469cbd01 | 258 | struct type_mismatch_data_v1 *data = _data; |
42440c1f AR |
259 | struct type_mismatch_data_common common_data = { |
260 | .location = &data->location, | |
261 | .type = data->type, | |
262 | .alignment = 1UL << data->log_alignment, | |
263 | .type_check_kind = data->type_check_kind | |
264 | }; | |
265 | ||
f0996bc2 | 266 | ubsan_type_mismatch_common(&common_data, (unsigned long)ptr); |
42440c1f AR |
267 | } |
268 | EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1); | |
269 | ||
469cbd01 | 270 | void __ubsan_handle_out_of_bounds(void *_data, void *index) |
c6d30853 | 271 | { |
469cbd01 | 272 | struct out_of_bounds_data *data = _data; |
c6d30853 AR |
273 | char index_str[VALUE_LENGTH]; |
274 | ||
275 | if (suppress_report(&data->location)) | |
276 | return; | |
277 | ||
ef065653 | 278 | ubsan_prologue(&data->location, "array-index-out-of-bounds"); |
c6d30853 AR |
279 | |
280 | val_to_string(index_str, sizeof(index_str), data->index_type, index); | |
281 | pr_err("index %s is out of range for type %s\n", index_str, | |
282 | data->array_type->type_name); | |
ce5c31db | 283 | ubsan_epilogue(); |
c6d30853 AR |
284 | } |
285 | EXPORT_SYMBOL(__ubsan_handle_out_of_bounds); | |
286 | ||
469cbd01 | 287 | void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs) |
c6d30853 | 288 | { |
469cbd01 | 289 | struct shift_out_of_bounds_data *data = _data; |
c6d30853 AR |
290 | struct type_descriptor *rhs_type = data->rhs_type; |
291 | struct type_descriptor *lhs_type = data->lhs_type; | |
292 | char rhs_str[VALUE_LENGTH]; | |
293 | char lhs_str[VALUE_LENGTH]; | |
9a50dcaf | 294 | unsigned long ua_flags = user_access_save(); |
c6d30853 AR |
295 | |
296 | if (suppress_report(&data->location)) | |
9a50dcaf | 297 | goto out; |
c6d30853 | 298 | |
ef065653 | 299 | ubsan_prologue(&data->location, "shift-out-of-bounds"); |
c6d30853 AR |
300 | |
301 | val_to_string(rhs_str, sizeof(rhs_str), rhs_type, rhs); | |
302 | val_to_string(lhs_str, sizeof(lhs_str), lhs_type, lhs); | |
303 | ||
304 | if (val_is_negative(rhs_type, rhs)) | |
305 | pr_err("shift exponent %s is negative\n", rhs_str); | |
306 | ||
307 | else if (get_unsigned_val(rhs_type, rhs) >= | |
308 | type_bit_width(lhs_type)) | |
309 | pr_err("shift exponent %s is too large for %u-bit type %s\n", | |
310 | rhs_str, | |
311 | type_bit_width(lhs_type), | |
312 | lhs_type->type_name); | |
313 | else if (val_is_negative(lhs_type, lhs)) | |
314 | pr_err("left shift of negative value %s\n", | |
315 | lhs_str); | |
316 | else | |
317 | pr_err("left shift of %s by %s places cannot be" | |
318 | " represented in type %s\n", | |
319 | lhs_str, rhs_str, | |
320 | lhs_type->type_name); | |
321 | ||
ce5c31db | 322 | ubsan_epilogue(); |
9a50dcaf PZ |
323 | out: |
324 | user_access_restore(ua_flags); | |
c6d30853 AR |
325 | } |
326 | EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds); | |
327 | ||
328 | ||
469cbd01 | 329 | void __ubsan_handle_builtin_unreachable(void *_data) |
c6d30853 | 330 | { |
469cbd01 | 331 | struct unreachable_data *data = _data; |
ef065653 | 332 | ubsan_prologue(&data->location, "unreachable"); |
c6d30853 | 333 | pr_err("calling __builtin_unreachable()\n"); |
ce5c31db | 334 | ubsan_epilogue(); |
c6d30853 AR |
335 | panic("can't return from __builtin_unreachable()"); |
336 | } | |
337 | EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable); | |
338 | ||
469cbd01 | 339 | void __ubsan_handle_load_invalid_value(void *_data, void *val) |
c6d30853 | 340 | { |
469cbd01 | 341 | struct invalid_value_data *data = _data; |
c6d30853 AR |
342 | char val_str[VALUE_LENGTH]; |
343 | ||
344 | if (suppress_report(&data->location)) | |
345 | return; | |
346 | ||
ef065653 | 347 | ubsan_prologue(&data->location, "invalid-load"); |
c6d30853 AR |
348 | |
349 | val_to_string(val_str, sizeof(val_str), data->type, val); | |
350 | ||
351 | pr_err("load of value %s is not a valid value for type %s\n", | |
352 | val_str, data->type->type_name); | |
353 | ||
ce5c31db | 354 | ubsan_epilogue(); |
c6d30853 AR |
355 | } |
356 | EXPORT_SYMBOL(__ubsan_handle_load_invalid_value); | |
28abcc96 NC |
357 | |
358 | void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, | |
359 | unsigned long align, | |
360 | unsigned long offset); | |
361 | void __ubsan_handle_alignment_assumption(void *_data, unsigned long ptr, | |
362 | unsigned long align, | |
363 | unsigned long offset) | |
364 | { | |
365 | struct alignment_assumption_data *data = _data; | |
366 | unsigned long real_ptr; | |
367 | ||
368 | if (suppress_report(&data->location)) | |
369 | return; | |
370 | ||
371 | ubsan_prologue(&data->location, "alignment-assumption"); | |
372 | ||
373 | if (offset) | |
374 | pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed", | |
375 | align, offset, data->type->type_name); | |
376 | else | |
377 | pr_err("assumption of %lu byte alignment for pointer of type %s failed", | |
378 | align, data->type->type_name); | |
379 | ||
380 | real_ptr = ptr - offset; | |
381 | pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes", | |
382 | offset ? "offset " : "", BIT(real_ptr ? __ffs(real_ptr) : 0), | |
383 | real_ptr & (align - 1)); | |
384 | ||
385 | ubsan_epilogue(); | |
386 | } | |
387 | EXPORT_SYMBOL(__ubsan_handle_alignment_assumption); |