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 <linux/ubsan.h>
18 #include <kunit/test-bug.h>
22 #ifdef CONFIG_UBSAN_TRAP
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/.
28 const char *report_ubsan_failure(struct pt_regs
*regs
, u32 check_type
)
31 #ifdef CONFIG_UBSAN_BOUNDS
33 * SanitizerKind::ArrayBounds and SanitizerKind::LocalBounds
34 * emit SanitizerHandler::OutOfBounds.
36 case ubsan_out_of_bounds
:
37 return "UBSAN: array index out of bounds";
39 #ifdef CONFIG_UBSAN_SHIFT
41 * SanitizerKind::ShiftBase and SanitizerKind::ShiftExponent
42 * emit SanitizerHandler::ShiftOutOfBounds.
44 case ubsan_shift_out_of_bounds
:
45 return "UBSAN: shift out of bounds";
47 #ifdef CONFIG_UBSAN_DIV_ZERO
49 * SanitizerKind::IntegerDivideByZero emits
50 * SanitizerHandler::DivremOverflow.
52 case ubsan_divrem_overflow
:
53 return "UBSAN: divide/remainder overflow";
55 #ifdef CONFIG_UBSAN_UNREACHABLE
57 * SanitizerKind::Unreachable emits
58 * SanitizerHandler::BuiltinUnreachable.
60 case ubsan_builtin_unreachable
:
61 return "UBSAN: unreachable code";
63 #if defined(CONFIG_UBSAN_BOOL) || defined(CONFIG_UBSAN_ENUM)
65 * SanitizerKind::Bool and SanitizerKind::Enum emit
66 * SanitizerHandler::LoadInvalidValue.
68 case ubsan_load_invalid_value
:
69 return "UBSAN: loading invalid value";
71 #ifdef CONFIG_UBSAN_ALIGNMENT
73 * SanitizerKind::Alignment emits SanitizerHandler::TypeMismatch
74 * or SanitizerHandler::AlignmentAssumption.
76 case ubsan_alignment_assumption
:
77 return "UBSAN: alignment assumption";
78 case ubsan_type_mismatch
:
79 return "UBSAN: type mismatch";
82 return "UBSAN: unrecognized failure code";
87 static const char * const type_check_kinds
[] = {
90 "reference binding to",
91 "member access within",
93 "constructor call on",
98 #define REPORTED_BIT 31
100 #if (BITS_PER_LONG == 64) && defined(__BIG_ENDIAN)
101 #define COLUMN_MASK (~(1U << REPORTED_BIT))
102 #define LINE_MASK (~0U)
104 #define COLUMN_MASK (~0U)
105 #define LINE_MASK (~(1U << REPORTED_BIT))
108 #define VALUE_LENGTH 40
110 static bool was_reported(struct source_location
*location
)
112 return test_and_set_bit(REPORTED_BIT
, &location
->reported
);
115 static bool suppress_report(struct source_location
*loc
)
117 return current
->in_ubsan
|| was_reported(loc
);
120 static bool type_is_int(struct type_descriptor
*type
)
122 return type
->type_kind
== type_kind_int
;
125 static bool type_is_signed(struct type_descriptor
*type
)
127 WARN_ON(!type_is_int(type
));
128 return type
->type_info
& 1;
131 static unsigned type_bit_width(struct type_descriptor
*type
)
133 return 1 << (type
->type_info
>> 1);
136 static bool is_inline_int(struct type_descriptor
*type
)
138 unsigned inline_bits
= sizeof(unsigned long)*8;
139 unsigned bits
= type_bit_width(type
);
141 WARN_ON(!type_is_int(type
));
143 return bits
<= inline_bits
;
146 static s_max
get_signed_val(struct type_descriptor
*type
, void *val
)
148 if (is_inline_int(type
)) {
149 unsigned extra_bits
= sizeof(s_max
)*8 - type_bit_width(type
);
150 unsigned long ulong_val
= (unsigned long)val
;
152 return ((s_max
)ulong_val
) << extra_bits
>> extra_bits
;
155 if (type_bit_width(type
) == 64)
158 return *(s_max
*)val
;
161 static bool val_is_negative(struct type_descriptor
*type
, void *val
)
163 return type_is_signed(type
) && get_signed_val(type
, val
) < 0;
166 static u_max
get_unsigned_val(struct type_descriptor
*type
, void *val
)
168 if (is_inline_int(type
))
169 return (unsigned long)val
;
171 if (type_bit_width(type
) == 64)
174 return *(u_max
*)val
;
177 static void val_to_string(char *str
, size_t size
, struct type_descriptor
*type
,
180 if (type_is_int(type
)) {
181 if (type_bit_width(type
) == 128) {
182 #if defined(CONFIG_ARCH_SUPPORTS_INT128)
183 u_max val
= get_unsigned_val(type
, value
);
185 scnprintf(str
, size
, "0x%08x%08x%08x%08x",
193 } else if (type_is_signed(type
)) {
194 scnprintf(str
, size
, "%lld",
195 (s64
)get_signed_val(type
, value
));
197 scnprintf(str
, size
, "%llu",
198 (u64
)get_unsigned_val(type
, value
));
203 static void ubsan_prologue(struct source_location
*loc
, const char *reason
)
207 pr_err("========================================"
208 "========================================\n");
209 pr_err("UBSAN: %s in %s:%d:%d\n", reason
, loc
->file_name
,
210 loc
->line
& LINE_MASK
, loc
->column
& COLUMN_MASK
);
212 kunit_fail_current_test("%s in %s", reason
, loc
->file_name
);
215 static void ubsan_epilogue(void)
218 pr_err("========================================"
219 "========================================\n");
223 check_panic_on_warn("UBSAN");
226 void __ubsan_handle_divrem_overflow(void *_data
, void *lhs
, void *rhs
)
228 struct overflow_data
*data
= _data
;
229 char rhs_val_str
[VALUE_LENGTH
];
231 if (suppress_report(&data
->location
))
234 ubsan_prologue(&data
->location
, "division-overflow");
236 val_to_string(rhs_val_str
, sizeof(rhs_val_str
), data
->type
, rhs
);
238 if (type_is_signed(data
->type
) && get_signed_val(data
->type
, rhs
) == -1)
239 pr_err("division of %s by -1 cannot be represented in type %s\n",
240 rhs_val_str
, data
->type
->type_name
);
242 pr_err("division by zero\n");
246 EXPORT_SYMBOL(__ubsan_handle_divrem_overflow
);
248 static void handle_null_ptr_deref(struct type_mismatch_data_common
*data
)
250 if (suppress_report(data
->location
))
253 ubsan_prologue(data
->location
, "null-ptr-deref");
255 pr_err("%s null pointer of type %s\n",
256 type_check_kinds
[data
->type_check_kind
],
257 data
->type
->type_name
);
262 static void handle_misaligned_access(struct type_mismatch_data_common
*data
,
265 if (suppress_report(data
->location
))
268 ubsan_prologue(data
->location
, "misaligned-access");
270 pr_err("%s misaligned address %p for type %s\n",
271 type_check_kinds
[data
->type_check_kind
],
272 (void *)ptr
, data
->type
->type_name
);
273 pr_err("which requires %ld byte alignment\n", data
->alignment
);
278 static void handle_object_size_mismatch(struct type_mismatch_data_common
*data
,
281 if (suppress_report(data
->location
))
284 ubsan_prologue(data
->location
, "object-size-mismatch");
285 pr_err("%s address %p with insufficient space\n",
286 type_check_kinds
[data
->type_check_kind
],
288 pr_err("for an object of type %s\n", data
->type
->type_name
);
292 static void ubsan_type_mismatch_common(struct type_mismatch_data_common
*data
,
295 unsigned long flags
= user_access_save();
298 handle_null_ptr_deref(data
);
299 else if (data
->alignment
&& !IS_ALIGNED(ptr
, data
->alignment
))
300 handle_misaligned_access(data
, ptr
);
302 handle_object_size_mismatch(data
, ptr
);
304 user_access_restore(flags
);
307 void __ubsan_handle_type_mismatch(struct type_mismatch_data
*data
,
310 struct type_mismatch_data_common common_data
= {
311 .location
= &data
->location
,
313 .alignment
= data
->alignment
,
314 .type_check_kind
= data
->type_check_kind
317 ubsan_type_mismatch_common(&common_data
, (unsigned long)ptr
);
319 EXPORT_SYMBOL(__ubsan_handle_type_mismatch
);
321 void __ubsan_handle_type_mismatch_v1(void *_data
, void *ptr
)
323 struct type_mismatch_data_v1
*data
= _data
;
324 struct type_mismatch_data_common common_data
= {
325 .location
= &data
->location
,
327 .alignment
= 1UL << data
->log_alignment
,
328 .type_check_kind
= data
->type_check_kind
331 ubsan_type_mismatch_common(&common_data
, (unsigned long)ptr
);
333 EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1
);
335 void __ubsan_handle_out_of_bounds(void *_data
, void *index
)
337 struct out_of_bounds_data
*data
= _data
;
338 char index_str
[VALUE_LENGTH
];
340 if (suppress_report(&data
->location
))
343 ubsan_prologue(&data
->location
, "array-index-out-of-bounds");
345 val_to_string(index_str
, sizeof(index_str
), data
->index_type
, index
);
346 pr_err("index %s is out of range for type %s\n", index_str
,
347 data
->array_type
->type_name
);
350 EXPORT_SYMBOL(__ubsan_handle_out_of_bounds
);
352 void __ubsan_handle_shift_out_of_bounds(void *_data
, void *lhs
, void *rhs
)
354 struct shift_out_of_bounds_data
*data
= _data
;
355 struct type_descriptor
*rhs_type
= data
->rhs_type
;
356 struct type_descriptor
*lhs_type
= data
->lhs_type
;
357 char rhs_str
[VALUE_LENGTH
];
358 char lhs_str
[VALUE_LENGTH
];
359 unsigned long ua_flags
= user_access_save();
361 if (suppress_report(&data
->location
))
364 ubsan_prologue(&data
->location
, "shift-out-of-bounds");
366 val_to_string(rhs_str
, sizeof(rhs_str
), rhs_type
, rhs
);
367 val_to_string(lhs_str
, sizeof(lhs_str
), lhs_type
, lhs
);
369 if (val_is_negative(rhs_type
, rhs
))
370 pr_err("shift exponent %s is negative\n", rhs_str
);
372 else if (get_unsigned_val(rhs_type
, rhs
) >=
373 type_bit_width(lhs_type
))
374 pr_err("shift exponent %s is too large for %u-bit type %s\n",
376 type_bit_width(lhs_type
),
377 lhs_type
->type_name
);
378 else if (val_is_negative(lhs_type
, lhs
))
379 pr_err("left shift of negative value %s\n",
382 pr_err("left shift of %s by %s places cannot be"
383 " represented in type %s\n",
385 lhs_type
->type_name
);
389 user_access_restore(ua_flags
);
391 EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds
);
394 void __ubsan_handle_builtin_unreachable(void *_data
)
396 struct unreachable_data
*data
= _data
;
397 ubsan_prologue(&data
->location
, "unreachable");
398 pr_err("calling __builtin_unreachable()\n");
400 panic("can't return from __builtin_unreachable()");
402 EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable
);
404 void __ubsan_handle_load_invalid_value(void *_data
, void *val
)
406 struct invalid_value_data
*data
= _data
;
407 char val_str
[VALUE_LENGTH
];
408 unsigned long ua_flags
= user_access_save();
410 if (suppress_report(&data
->location
))
413 ubsan_prologue(&data
->location
, "invalid-load");
415 val_to_string(val_str
, sizeof(val_str
), data
->type
, val
);
417 pr_err("load of value %s is not a valid value for type %s\n",
418 val_str
, data
->type
->type_name
);
422 user_access_restore(ua_flags
);
424 EXPORT_SYMBOL(__ubsan_handle_load_invalid_value
);
426 void __ubsan_handle_alignment_assumption(void *_data
, unsigned long ptr
,
428 unsigned long offset
)
430 struct alignment_assumption_data
*data
= _data
;
431 unsigned long real_ptr
;
433 if (suppress_report(&data
->location
))
436 ubsan_prologue(&data
->location
, "alignment-assumption");
439 pr_err("assumption of %lu byte alignment (with offset of %lu byte) for pointer of type %s failed",
440 align
, offset
, data
->type
->type_name
);
442 pr_err("assumption of %lu byte alignment for pointer of type %s failed",
443 align
, data
->type
->type_name
);
445 real_ptr
= ptr
- offset
;
446 pr_err("%saddress is %lu aligned, misalignment offset is %lu bytes",
447 offset
? "offset " : "", BIT(real_ptr
? __ffs(real_ptr
) : 0),
448 real_ptr
& (align
- 1));
452 EXPORT_SYMBOL(__ubsan_handle_alignment_assumption
);
454 #endif /* !CONFIG_UBSAN_TRAP */