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>
20 static const char * const type_check_kinds
[] = {
23 "reference binding to",
24 "member access within",
26 "constructor call on",
31 #define REPORTED_BIT 31
33 #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)
34 #define COLUMN_MASK (~(1U << REPORTED_BIT))
35 #define LINE_MASK (~0U)
37 #define COLUMN_MASK (~0U)
38 #define LINE_MASK (~(1U << REPORTED_BIT))
41 #define VALUE_LENGTH 40
43 static bool was_reported(struct source_location
*location
)
45 return test_and_set_bit(REPORTED_BIT
, &location
->reported
);
48 static bool suppress_report(struct source_location
*loc
)
50 return current
->in_ubsan
|| was_reported(loc
);
53 static bool type_is_int(struct type_descriptor
*type
)
55 return type
->type_kind
== type_kind_int
;
58 static bool type_is_signed(struct type_descriptor
*type
)
60 WARN_ON(!type_is_int(type
));
61 return type
->type_info
& 1;
64 static unsigned type_bit_width(struct type_descriptor
*type
)
66 return 1 << (type
->type_info
>> 1);
69 static bool is_inline_int(struct type_descriptor
*type
)
71 unsigned inline_bits
= sizeof(unsigned long)*8;
72 unsigned bits
= type_bit_width(type
);
74 WARN_ON(!type_is_int(type
));
76 return bits
<= inline_bits
;
79 static s_max
get_signed_val(struct type_descriptor
*type
, void *val
)
81 if (is_inline_int(type
)) {
82 unsigned extra_bits
= sizeof(s_max
)*8 - type_bit_width(type
);
83 unsigned long ulong_val
= (unsigned long)val
;
85 return ((s_max
)ulong_val
) << extra_bits
>> extra_bits
;
88 if (type_bit_width(type
) == 64)
94 static bool val_is_negative(struct type_descriptor
*type
, void *val
)
96 return type_is_signed(type
) && get_signed_val(type
, val
) < 0;
99 static u_max
get_unsigned_val(struct type_descriptor
*type
, void *val
)
101 if (is_inline_int(type
))
102 return (unsigned long)val
;
104 if (type_bit_width(type
) == 64)
107 return *(u_max
*)val
;
110 static void val_to_string(char *str
, size_t size
, struct type_descriptor
*type
,
113 if (type_is_int(type
)) {
114 if (type_bit_width(type
) == 128) {
115 #if defined(CONFIG_ARCH_SUPPORTS_INT128)
116 u_max val
= get_unsigned_val(type
, value
);
118 scnprintf(str
, size
, "0x%08x%08x%08x%08x",
126 } else if (type_is_signed(type
)) {
127 scnprintf(str
, size
, "%lld",
128 (s64
)get_signed_val(type
, value
));
130 scnprintf(str
, size
, "%llu",
131 (u64
)get_unsigned_val(type
, value
));
136 static void ubsan_prologue(struct source_location
*loc
, const char *reason
)
140 pr_err("========================================"
141 "========================================\n");
142 pr_err("UBSAN: %s in %s:%d:%d\n", reason
, loc
->file_name
,
143 loc
->line
& LINE_MASK
, loc
->column
& COLUMN_MASK
);
146 static void ubsan_epilogue(void)
149 pr_err("========================================"
150 "========================================\n");
156 * This thread may hit another WARN() in the panic path.
157 * Resetting this prevents additional WARN() from panicking the
158 * system on this thread. Other threads are blocked by the
159 * panic_mutex in panic().
162 panic("panic_on_warn set ...\n");
166 void __ubsan_handle_divrem_overflow(void *_data
, void *lhs
, void *rhs
)
168 struct overflow_data
*data
= _data
;
169 char rhs_val_str
[VALUE_LENGTH
];
171 if (suppress_report(&data
->location
))
174 ubsan_prologue(&data
->location
, "division-overflow");
176 val_to_string(rhs_val_str
, sizeof(rhs_val_str
), data
->type
, rhs
);
178 if (type_is_signed(data
->type
) && get_signed_val(data
->type
, rhs
) == -1)
179 pr_err("division of %s by -1 cannot be represented in type %s\n",
180 rhs_val_str
, data
->type
->type_name
);
182 pr_err("division by zero\n");
186 EXPORT_SYMBOL(__ubsan_handle_divrem_overflow
);
188 static void handle_null_ptr_deref(struct type_mismatch_data_common
*data
)
190 if (suppress_report(data
->location
))
193 ubsan_prologue(data
->location
, "null-ptr-deref");
195 pr_err("%s null pointer of type %s\n",
196 type_check_kinds
[data
->type_check_kind
],
197 data
->type
->type_name
);
202 static void handle_misaligned_access(struct type_mismatch_data_common
*data
,
205 if (suppress_report(data
->location
))
208 ubsan_prologue(data
->location
, "misaligned-access");
210 pr_err("%s misaligned address %p for type %s\n",
211 type_check_kinds
[data
->type_check_kind
],
212 (void *)ptr
, data
->type
->type_name
);
213 pr_err("which requires %ld byte alignment\n", data
->alignment
);
218 static void handle_object_size_mismatch(struct type_mismatch_data_common
*data
,
221 if (suppress_report(data
->location
))
224 ubsan_prologue(data
->location
, "object-size-mismatch");
225 pr_err("%s address %p with insufficient space\n",
226 type_check_kinds
[data
->type_check_kind
],
228 pr_err("for an object of type %s\n", data
->type
->type_name
);
232 static void ubsan_type_mismatch_common(struct type_mismatch_data_common
*data
,
235 unsigned long flags
= user_access_save();
238 handle_null_ptr_deref(data
);
239 else if (data
->alignment
&& !IS_ALIGNED(ptr
, data
->alignment
))
240 handle_misaligned_access(data
, ptr
);
242 handle_object_size_mismatch(data
, ptr
);
244 user_access_restore(flags
);
247 void __ubsan_handle_type_mismatch(struct type_mismatch_data
*data
,
250 struct type_mismatch_data_common common_data
= {
251 .location
= &data
->location
,
253 .alignment
= data
->alignment
,
254 .type_check_kind
= data
->type_check_kind
257 ubsan_type_mismatch_common(&common_data
, (unsigned long)ptr
);
259 EXPORT_SYMBOL(__ubsan_handle_type_mismatch
);
261 void __ubsan_handle_type_mismatch_v1(void *_data
, void *ptr
)
263 struct type_mismatch_data_v1
*data
= _data
;
264 struct type_mismatch_data_common common_data
= {
265 .location
= &data
->location
,
267 .alignment
= 1UL << data
->log_alignment
,
268 .type_check_kind
= data
->type_check_kind
271 ubsan_type_mismatch_common(&common_data
, (unsigned long)ptr
);
273 EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1
);
275 void __ubsan_handle_out_of_bounds(void *_data
, void *index
)
277 struct out_of_bounds_data
*data
= _data
;
278 char index_str
[VALUE_LENGTH
];
280 if (suppress_report(&data
->location
))
283 ubsan_prologue(&data
->location
, "array-index-out-of-bounds");
285 val_to_string(index_str
, sizeof(index_str
), data
->index_type
, index
);
286 pr_err("index %s is out of range for type %s\n", index_str
,
287 data
->array_type
->type_name
);
290 EXPORT_SYMBOL(__ubsan_handle_out_of_bounds
);
292 void __ubsan_handle_shift_out_of_bounds(void *_data
, void *lhs
, void *rhs
)
294 struct shift_out_of_bounds_data
*data
= _data
;
295 struct type_descriptor
*rhs_type
= data
->rhs_type
;
296 struct type_descriptor
*lhs_type
= data
->lhs_type
;
297 char rhs_str
[VALUE_LENGTH
];
298 char lhs_str
[VALUE_LENGTH
];
299 unsigned long ua_flags
= user_access_save();
301 if (suppress_report(&data
->location
))
304 ubsan_prologue(&data
->location
, "shift-out-of-bounds");
306 val_to_string(rhs_str
, sizeof(rhs_str
), rhs_type
, rhs
);
307 val_to_string(lhs_str
, sizeof(lhs_str
), lhs_type
, lhs
);
309 if (val_is_negative(rhs_type
, rhs
))
310 pr_err("shift exponent %s is negative\n", rhs_str
);
312 else if (get_unsigned_val(rhs_type
, rhs
) >=
313 type_bit_width(lhs_type
))
314 pr_err("shift exponent %s is too large for %u-bit type %s\n",
316 type_bit_width(lhs_type
),
317 lhs_type
->type_name
);
318 else if (val_is_negative(lhs_type
, lhs
))
319 pr_err("left shift of negative value %s\n",
322 pr_err("left shift of %s by %s places cannot be"
323 " represented in type %s\n",
325 lhs_type
->type_name
);
329 user_access_restore(ua_flags
);
331 EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds
);
334 void __ubsan_handle_builtin_unreachable(void *_data
)
336 struct unreachable_data
*data
= _data
;
337 ubsan_prologue(&data
->location
, "unreachable");
338 pr_err("calling __builtin_unreachable()\n");
340 panic("can't return from __builtin_unreachable()");
342 EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable
);
344 void __ubsan_handle_load_invalid_value(void *_data
, void *val
)
346 struct invalid_value_data
*data
= _data
;
347 char val_str
[VALUE_LENGTH
];
349 if (suppress_report(&data
->location
))
352 ubsan_prologue(&data
->location
, "invalid-load");
354 val_to_string(val_str
, sizeof(val_str
), data
->type
, val
);
356 pr_err("load of value %s is not a valid value for type %s\n",
357 val_str
, data
->type
->type_name
);
361 EXPORT_SYMBOL(__ubsan_handle_load_invalid_value
);
363 void __ubsan_handle_alignment_assumption(void *_data
, unsigned long ptr
,
365 unsigned long offset
);
366 void __ubsan_handle_alignment_assumption(void *_data
, unsigned long ptr
,
368 unsigned long offset
)
370 struct alignment_assumption_data
*data
= _data
;
371 unsigned long real_ptr
;
373 if (suppress_report(&data
->location
))
376 ubsan_prologue(&data
->location
, "alignment-assumption");
379 pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed",
380 align
, offset
, data
->type
->type_name
);
382 pr_err("assumption of %lu byte alignment for pointer of type %s failed",
383 align
, data
->type
->type_name
);
385 real_ptr
= ptr
- offset
;
386 pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes",
387 offset
? "offset " : "", BIT(real_ptr
? __ffs(real_ptr
) : 0),
388 real_ptr
& (align
- 1));
392 EXPORT_SYMBOL(__ubsan_handle_alignment_assumption
);