Merge tag 'trace-v5.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt...
[linux-2.6-microblaze.git] / lib / ubsan.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * UBSAN error reporting functions
4  *
5  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
6  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
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>
16 #include <linux/uaccess.h>
17 #include <kunit/test-bug.h>
18
19 #include "ubsan.h"
20
21 static const char * const type_check_kinds[] = {
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
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
80 static s_max get_signed_val(struct type_descriptor *type, void *val)
81 {
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;
85
86                 return ((s_max)ulong_val) << extra_bits >> extra_bits;
87         }
88
89         if (type_bit_width(type) == 64)
90                 return *(s64 *)val;
91
92         return *(s_max *)val;
93 }
94
95 static bool val_is_negative(struct type_descriptor *type, void *val)
96 {
97         return type_is_signed(type) && get_signed_val(type, val) < 0;
98 }
99
100 static u_max get_unsigned_val(struct type_descriptor *type, void *val)
101 {
102         if (is_inline_int(type))
103                 return (unsigned long)val;
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,
112                         void *value)
113 {
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);
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
137 static void ubsan_prologue(struct source_location *loc, const char *reason)
138 {
139         current->in_ubsan++;
140
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);
145
146         kunit_fail_current_test("%s in %s", reason, loc->file_name);
147 }
148
149 static void ubsan_epilogue(void)
150 {
151         dump_stack();
152         pr_err("========================================"
153                 "========================================\n");
154
155         current->in_ubsan--;
156
157         if (panic_on_warn)
158                 panic("panic_on_warn set ...\n");
159 }
160
161 void __ubsan_handle_divrem_overflow(void *_data, void *lhs, void *rhs)
162 {
163         struct overflow_data *data = _data;
164         char rhs_val_str[VALUE_LENGTH];
165
166         if (suppress_report(&data->location))
167                 return;
168
169         ubsan_prologue(&data->location, "division-overflow");
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
179         ubsan_epilogue();
180 }
181 EXPORT_SYMBOL(__ubsan_handle_divrem_overflow);
182
183 static void handle_null_ptr_deref(struct type_mismatch_data_common *data)
184 {
185         if (suppress_report(data->location))
186                 return;
187
188         ubsan_prologue(data->location, "null-ptr-deref");
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
194         ubsan_epilogue();
195 }
196
197 static void handle_misaligned_access(struct type_mismatch_data_common *data,
198                                 unsigned long ptr)
199 {
200         if (suppress_report(data->location))
201                 return;
202
203         ubsan_prologue(data->location, "misaligned-access");
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
210         ubsan_epilogue();
211 }
212
213 static void handle_object_size_mismatch(struct type_mismatch_data_common *data,
214                                         unsigned long ptr)
215 {
216         if (suppress_report(data->location))
217                 return;
218
219         ubsan_prologue(data->location, "object-size-mismatch");
220         pr_err("%s address %p with insufficient space\n",
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);
224         ubsan_epilogue();
225 }
226
227 static void ubsan_type_mismatch_common(struct type_mismatch_data_common *data,
228                                 unsigned long ptr)
229 {
230         unsigned long flags = user_access_save();
231
232         if (!ptr)
233                 handle_null_ptr_deref(data);
234         else if (data->alignment && !IS_ALIGNED(ptr, data->alignment))
235                 handle_misaligned_access(data, ptr);
236         else
237                 handle_object_size_mismatch(data, ptr);
238
239         user_access_restore(flags);
240 }
241
242 void __ubsan_handle_type_mismatch(struct type_mismatch_data *data,
243                                 void *ptr)
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
252         ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
253 }
254 EXPORT_SYMBOL(__ubsan_handle_type_mismatch);
255
256 void __ubsan_handle_type_mismatch_v1(void *_data, void *ptr)
257 {
258         struct type_mismatch_data_v1 *data = _data;
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
266         ubsan_type_mismatch_common(&common_data, (unsigned long)ptr);
267 }
268 EXPORT_SYMBOL(__ubsan_handle_type_mismatch_v1);
269
270 void __ubsan_handle_out_of_bounds(void *_data, void *index)
271 {
272         struct out_of_bounds_data *data = _data;
273         char index_str[VALUE_LENGTH];
274
275         if (suppress_report(&data->location))
276                 return;
277
278         ubsan_prologue(&data->location, "array-index-out-of-bounds");
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);
283         ubsan_epilogue();
284 }
285 EXPORT_SYMBOL(__ubsan_handle_out_of_bounds);
286
287 void __ubsan_handle_shift_out_of_bounds(void *_data, void *lhs, void *rhs)
288 {
289         struct shift_out_of_bounds_data *data = _data;
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];
294         unsigned long ua_flags = user_access_save();
295
296         if (suppress_report(&data->location))
297                 goto out;
298
299         ubsan_prologue(&data->location, "shift-out-of-bounds");
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
322         ubsan_epilogue();
323 out:
324         user_access_restore(ua_flags);
325 }
326 EXPORT_SYMBOL(__ubsan_handle_shift_out_of_bounds);
327
328
329 void __ubsan_handle_builtin_unreachable(void *_data)
330 {
331         struct unreachable_data *data = _data;
332         ubsan_prologue(&data->location, "unreachable");
333         pr_err("calling __builtin_unreachable()\n");
334         ubsan_epilogue();
335         panic("can't return from __builtin_unreachable()");
336 }
337 EXPORT_SYMBOL(__ubsan_handle_builtin_unreachable);
338
339 void __ubsan_handle_load_invalid_value(void *_data, void *val)
340 {
341         struct invalid_value_data *data = _data;
342         char val_str[VALUE_LENGTH];
343
344         if (suppress_report(&data->location))
345                 return;
346
347         ubsan_prologue(&data->location, "invalid-load");
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
354         ubsan_epilogue();
355 }
356 EXPORT_SYMBOL(__ubsan_handle_load_invalid_value);
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);