1 // SPDX-License-Identifier: GPL-2.0-only
3 * UBSAN error reporting functions
5 * Copyright (c) 2014 Samsung Electronics Co., Ltd.
6 * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
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 <kunit/test-bug.h>
21 static const char * const type_check_kinds
[] = {
24 "reference binding to",
25 "member access within",
27 "constructor call on",
32 #define REPORTED_BIT 31
34 #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)
35 #define COLUMN_MASK (~(1U << REPORTED_BIT))
36 #define LINE_MASK (~0U)
38 #define COLUMN_MASK (~0U)
39 #define LINE_MASK (~(1U << REPORTED_BIT))
42 #define VALUE_LENGTH 40
44 static bool was_reported(struct source_location
*location
)
46 return test_and_set_bit(REPORTED_BIT
, &location
->reported
);
49 static bool suppress_report(struct source_location
*loc
)
51 return current
->in_ubsan
|| was_reported(loc
);
54 static bool type_is_int(struct type_descriptor
*type
)
56 return type
->type_kind
== type_kind_int
;
59 static bool type_is_signed(struct type_descriptor
*type
)
61 WARN_ON(!type_is_int(type
));
62 return type
->type_info
& 1;
65 static unsigned type_bit_width(struct type_descriptor
*type
)
67 return 1 << (type
->type_info
>> 1);
70 static bool is_inline_int(struct type_descriptor
*type
)
72 unsigned inline_bits
= sizeof(unsigned long)*8;
73 unsigned bits
= type_bit_width(type
);
75 WARN_ON(!type_is_int(type
));
77 return bits
<= inline_bits
;
80 static s_max
get_signed_val(struct type_descriptor
*type
, void *val
)
82 if (is_inline_int(type
)) {
83 unsigned extra_bits
= sizeof(s_max
)*8 - type_bit_width(type
);
84 unsigned long ulong_val
= (unsigned long)val
;
86 return ((s_max
)ulong_val
) << extra_bits
>> extra_bits
;
89 if (type_bit_width(type
) == 64)
95 static bool val_is_negative(struct type_descriptor
*type
, void *val
)
97 return type_is_signed(type
) && get_signed_val(type
, val
) < 0;
100 static u_max
get_unsigned_val(struct type_descriptor
*type
, void *val
)
102 if (is_inline_int(type
))
103 return (unsigned long)val
;
105 if (type_bit_width(type
) == 64)
108 return *(u_max
*)val
;
111 static void val_to_string(char *str
, size_t size
, struct type_descriptor
*type
,
114 if (type_is_int(type
)) {
115 if (type_bit_width(type
) == 128) {
116 #if defined(CONFIG_ARCH_SUPPORTS_INT128)
117 u_max val
= get_unsigned_val(type
, value
);
119 scnprintf(str
, size
, "0x%08x%08x%08x%08x",
127 } else if (type_is_signed(type
)) {
128 scnprintf(str
, size
, "%lld",
129 (s64
)get_signed_val(type
, value
));
131 scnprintf(str
, size
, "%llu",
132 (u64
)get_unsigned_val(type
, value
));
137 static void ubsan_prologue(struct source_location
*loc
, const char *reason
)
141 pr_err("========================================"
142 "========================================\n");
143 pr_err("UBSAN: %s in %s:%d:%d\n", reason
, loc
->file_name
,
144 loc
->line
& LINE_MASK
, loc
->column
& COLUMN_MASK
);
146 kunit_fail_current_test("%s in %s", reason
, loc
->file_name
);
149 static void ubsan_epilogue(void)
152 pr_err("========================================"
153 "========================================\n");
159 * This thread may hit another WARN() in the panic path.
160 * Resetting this prevents additional WARN() from panicking the
161 * system on this thread. Other threads are blocked by the
162 * panic_mutex in panic().
165 panic("panic_on_warn set ...\n");
169 void __ubsan_handle_divrem_overflow(void *_data
, void *lhs
, void *rhs
)
171 struct overflow_data
*data
= _data
;
172 char rhs_val_str
[VALUE_LENGTH
];
174 if (suppress_report(&data
->location
))
177 ubsan_prologue(&data
->location
, "division-overflow");
179 val_to_string(rhs_val_str
, sizeof(rhs_val_str
), data
->type
, rhs
);
181 if (type_is_signed(data
->type
) && get_signed_val(data
->type
, rhs
) == -1)
182 pr_err("division of %s by -1 cannot be represented in type %s\n",
183 rhs_val_str
, data
->type
->type_name
);
185 pr_err("division by zero\n");
189 EXPORT_SYMBOL(__ubsan_handle_divrem_overflow
);
191 static void handle_null_ptr_deref(struct type_mismatch_data_common
*data
)
193 if (suppress_report(data
->location
))
196 ubsan_prologue(data
->location
, "null-ptr-deref");
198 pr_err("%s null pointer of type %s\n",
199 type_check_kinds
[data
->type_check_kind
],
200 data
->type
->type_name
);
205 static void handle_misaligned_access(struct type_mismatch_data_common
*data
,
208 if (suppress_report(data
->location
))
211 ubsan_prologue(data
->location
, "misaligned-access");
213 pr_err("%s misaligned address %p for type %s\n",
214 type_check_kinds
[data
->type_check_kind
],
215 (void *)ptr
, data
->type
->type_name
);
216 pr_err("which requires %ld byte alignment\n", data
->alignment
);
221 static void handle_object_size_mismatch(struct type_mismatch_data_common
*data
,
224 if (suppress_report(data
->location
))
227 ubsan_prologue(data
->location
, "object-size-mismatch");
228 pr_err("%s address %p with insufficient space\n",
229 type_check_kinds
[data
->type_check_kind
],
231 pr_err("for an object of type %s\n", data
->type
->type_name
);
235 static void ubsan_type_mismatch_common(struct type_mismatch_data_common
*data
,
238 unsigned long flags
= user_access_save();
241 handle_null_ptr_deref(data
);
242 else if (data
->alignment
&& !IS_ALIGNED(ptr
, data
->alignment
))
243 handle_misaligned_access(data
, ptr
);
245 handle_object_size_mismatch(data
, ptr
);
247 user_access_restore(flags
);
250 void __ubsan_handle_type_mismatch(struct type_mismatch_data
*data
,
253 struct type_mismatch_data_common common_data
= {
254 .location
= &data
->location
,
256 .alignment
= data
->alignment
,
257 .type_check_kind
= data
->type_check_kind
260 ubsan_type_mismatch_common(&common_data
, (unsigned long)ptr
);
262 EXPORT_SYMBOL(__ubsan_handle_type_mismatch
);
264 void __ubsan_handle_type_mismatch_v1(void *_data
, void *ptr
)
266 struct type_mismatch_data_v1
*data
= _data
;
267 struct type_mismatch_data_common common_data
= {
268 .location
= &data
->location
,
270 .alignment
= 1UL << data
->log_alignment
,
271 .type_check_kind
= data
->type_check_kind
274 ubsan_type_mismatch_common(&common_data
, (unsigned long)ptr
);
276 EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1
);
278 void __ubsan_handle_out_of_bounds(void *_data
, void *index
)
280 struct out_of_bounds_data
*data
= _data
;
281 char index_str
[VALUE_LENGTH
];
283 if (suppress_report(&data
->location
))
286 ubsan_prologue(&data
->location
, "array-index-out-of-bounds");
288 val_to_string(index_str
, sizeof(index_str
), data
->index_type
, index
);
289 pr_err("index %s is out of range for type %s\n", index_str
,
290 data
->array_type
->type_name
);
293 EXPORT_SYMBOL(__ubsan_handle_out_of_bounds
);
295 void __ubsan_handle_shift_out_of_bounds(void *_data
, void *lhs
, void *rhs
)
297 struct shift_out_of_bounds_data
*data
= _data
;
298 struct type_descriptor
*rhs_type
= data
->rhs_type
;
299 struct type_descriptor
*lhs_type
= data
->lhs_type
;
300 char rhs_str
[VALUE_LENGTH
];
301 char lhs_str
[VALUE_LENGTH
];
302 unsigned long ua_flags
= user_access_save();
304 if (suppress_report(&data
->location
))
307 ubsan_prologue(&data
->location
, "shift-out-of-bounds");
309 val_to_string(rhs_str
, sizeof(rhs_str
), rhs_type
, rhs
);
310 val_to_string(lhs_str
, sizeof(lhs_str
), lhs_type
, lhs
);
312 if (val_is_negative(rhs_type
, rhs
))
313 pr_err("shift exponent %s is negative\n", rhs_str
);
315 else if (get_unsigned_val(rhs_type
, rhs
) >=
316 type_bit_width(lhs_type
))
317 pr_err("shift exponent %s is too large for %u-bit type %s\n",
319 type_bit_width(lhs_type
),
320 lhs_type
->type_name
);
321 else if (val_is_negative(lhs_type
, lhs
))
322 pr_err("left shift of negative value %s\n",
325 pr_err("left shift of %s by %s places cannot be"
326 " represented in type %s\n",
328 lhs_type
->type_name
);
332 user_access_restore(ua_flags
);
334 EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds
);
337 void __ubsan_handle_builtin_unreachable(void *_data
)
339 struct unreachable_data
*data
= _data
;
340 ubsan_prologue(&data
->location
, "unreachable");
341 pr_err("calling __builtin_unreachable()\n");
343 panic("can't return from __builtin_unreachable()");
345 EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable
);
347 void __ubsan_handle_load_invalid_value(void *_data
, void *val
)
349 struct invalid_value_data
*data
= _data
;
350 char val_str
[VALUE_LENGTH
];
352 if (suppress_report(&data
->location
))
355 ubsan_prologue(&data
->location
, "invalid-load");
357 val_to_string(val_str
, sizeof(val_str
), data
->type
, val
);
359 pr_err("load of value %s is not a valid value for type %s\n",
360 val_str
, data
->type
->type_name
);
364 EXPORT_SYMBOL(__ubsan_handle_load_invalid_value
);
366 void __ubsan_handle_alignment_assumption(void *_data
, unsigned long ptr
,
368 unsigned long offset
);
369 void __ubsan_handle_alignment_assumption(void *_data
, unsigned long ptr
,
371 unsigned long offset
)
373 struct alignment_assumption_data
*data
= _data
;
374 unsigned long real_ptr
;
376 if (suppress_report(&data
->location
))
379 ubsan_prologue(&data
->location
, "alignment-assumption");
382 pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed",
383 align
, offset
, data
->type
->type_name
);
385 pr_err("assumption of %lu byte alignment for pointer of type %s failed",
386 align
, data
->type
->type_name
);
388 real_ptr
= ptr
- offset
;
389 pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes",
390 offset
? "offset " : "", BIT(real_ptr
? __ffs(real_ptr
) : 0),
391 real_ptr
& (align
- 1));
395 EXPORT_SYMBOL(__ubsan_handle_alignment_assumption
);