1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
|
/* Test reporting of Safe-Linking caught errors.
Copyright (C) 2020-2023 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <time.h>
#include <stdbool.h>
#include <support/capture_subprocess.h>
#include <support/check.h>
/* Run CALLBACK and check that the data on standard error equals
EXPECTED. */
static void
check (const char *test, void (*callback) (void *),
const char *expected)
{
int i, rand_mask;
int success = 0; /* 0 == fail, 1 == other check 2 == safe linking */
/* There is a chance of 1/16 that a corrupted pointer will be aligned.
Try multiple times so that statistical failure will be improbable. */
for (i = 0; i < 16; ++i)
{
rand_mask = rand () & 0xFF;
struct support_capture_subprocess result
= support_capture_subprocess (callback, &rand_mask);
printf ("%s\n", result.out.buffer);
/* Did not crash, could happen. Try again. */
if (strlen (result.err.buffer) == 0)
continue;
/* Crashed, it may either be safe linking or some other check. If it's
not safe linking then try again. */
if (strcmp (result.err.buffer, expected) != 0)
{
printf ("test %s failed with a different error\n"
" expected: %s\n"
" actual: %s\n",
test, expected, result.err.buffer);
success = 1;
continue;
}
TEST_VERIFY (WIFSIGNALED (result.status));
if (WIFSIGNALED (result.status))
TEST_VERIFY (WTERMSIG (result.status) == SIGABRT);
support_capture_subprocess_free (&result);
success = 2;
break;
}
/* The test fails only if the corruption was not caught by any of the malloc
mechanisms in all those iterations. This has a lower than 1 in 2^64
chance of a false positive. */
TEST_VERIFY (success);
}
/* Implementation details must be kept in sync with malloc. */
#define TCACHE_FILL_COUNT 7
#define TCACHE_ALLOC_SIZE 0x20
#define MALLOC_CONSOLIDATE_SIZE 256*1024
/* Try corrupting the tcache list. */
static void
test_tcache (void *closure)
{
int mask = ((int *)closure)[0];
size_t size = TCACHE_ALLOC_SIZE;
printf ("++ tcache ++\n");
/* Populate the tcache list. */
void * volatile a = malloc (size);
void * volatile b = malloc (size);
void * volatile c = malloc (size);
printf ("a=%p, b=%p, c=%p\n", a, b, c);
free (a);
free (b);
free (c);
/* Corrupt the pointer with a random value, and avoid optimizations. */
printf ("Before: c=%p, c[0]=%p\n", c, ((void **)c)[0]);
memset (c, mask & 0xFF, size);
printf ("After: c=%p, c[0]=%p\n", c, ((void **)c)[0]);
c = malloc (size);
printf ("Allocated: c=%p\n", c);
/* This line will trigger the Safe-Linking check. */
b = malloc (size);
printf ("b=%p\n", b);
}
/* Try corrupting the fastbin list. */
static void
test_fastbin (void *closure)
{
int i;
int mask = ((int *)closure)[0];
size_t size = TCACHE_ALLOC_SIZE;
printf ("++ fastbin ++\n");
/* Take the tcache out of the game. */
for (i = 0; i < TCACHE_FILL_COUNT; ++i)
{
void * volatile p = calloc (1, size);
printf ("p=%p\n", p);
free (p);
}
/* Populate the fastbin list. */
void * volatile a = calloc (1, size);
void * volatile b = calloc (1, size);
void * volatile c = calloc (1, size);
printf ("a=%p, b=%p, c=%p\n", a, b, c);
free (a);
free (b);
free (c);
/* Corrupt the pointer with a random value, and avoid optimizations. */
printf ("Before: c=%p, c[0]=%p\n", c, ((void **)c)[0]);
memset (c, mask & 0xFF, size);
printf ("After: c=%p, c[0]=%p\n", c, ((void **)c)[0]);
c = calloc (1, size);
printf ("Allocated: c=%p\n", c);
/* This line will trigger the Safe-Linking check. */
b = calloc (1, size);
printf ("b=%p\n", b);
}
/* Try corrupting the fastbin list and trigger a consolidate. */
static void
test_fastbin_consolidate (void *closure)
{
int i;
int mask = ((int*)closure)[0];
size_t size = TCACHE_ALLOC_SIZE;
printf ("++ fastbin consolidate ++\n");
/* Take the tcache out of the game. */
for (i = 0; i < TCACHE_FILL_COUNT; ++i)
{
void * volatile p = calloc (1, size);
free (p);
}
/* Populate the fastbin list. */
void * volatile a = calloc (1, size);
void * volatile b = calloc (1, size);
void * volatile c = calloc (1, size);
printf ("a=%p, b=%p, c=%p\n", a, b, c);
free (a);
free (b);
free (c);
/* Corrupt the pointer with a random value, and avoid optimizations. */
printf ("Before: c=%p, c[0]=%p\n", c, ((void **)c)[0]);
memset (c, mask & 0xFF, size);
printf ("After: c=%p, c[0]=%p\n", c, ((void **)c)[0]);
/* This line will trigger the Safe-Linking check. */
b = malloc (MALLOC_CONSOLIDATE_SIZE);
printf ("b=%p\n", b);
}
static int
do_test (void)
{
/* Seed the random for the test. */
srand (time (NULL));
check ("test_tcache", test_tcache,
"malloc(): unaligned tcache chunk detected\n");
check ("test_fastbin", test_fastbin,
"malloc(): unaligned fastbin chunk detected 2\n");
check ("test_fastbin_consolidate", test_fastbin_consolidate,
"malloc_consolidate(): unaligned fastbin chunk detected\n");
return 0;
}
#include <support/test-driver.c>
|
