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
199
200
201
202
203
204
205
206
|
/*
* Copyright (c) 2010 Philip Guenther <guenther@openbsd.org>
*
* Public domain.
*
* Verify that mkdtemp() and mkstemps() doesn't overrun or underrun
* the template buffer and that it can generate names that don't
* contain any X's
*/
#include <config.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <errno.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#define SUDO_ERROR_WRAP 0
#include "sudo_compat.h"
#include "sudo_util.h"
#include "sudo_fatal.h"
#ifndef MAP_ANON
# if defined(MAP_ANONYMOUS)
# define MAP_ANON MAP_ANONYMOUS
# endif
#endif
#ifndef MAP_FAILED
# define MAP_FAILED ((void *) -1)
#endif
#define MAX_TEMPLATE_LEN 10
#define MAX_TRIES 100
#define MIN_Xs 6
#define SUFFIX ".suff"
#define SLEN (sizeof SUFFIX - 1)
sudo_dso_public int main(int argc, char *argv[]);
/*
* verify that a path generated by mkdtemp() or mkstemp() looks like a
* reasonable expansion of the template and matches the fd. Returns true
* if all the X's were replaced with non-X's
*/
static int
check(int fd, char const *kind, char const *path, char const *prefix,
size_t plen, char const *suffix, size_t slen, int tlen)
{
struct stat sb, fsb;
char const *p;
if (tlen < MIN_Xs) {
if (fd != -1)
sudo_fatalx("%s(%s) succeed with too few Xs", kind, path);
if (errno != EINVAL)
sudo_fatal("%s(%s) failed with wrong errno: %d", kind, path, errno);
return 1;
}
if (fd == -1)
sudo_fatal("%s(%s)", kind, path);
if (stat(path, &sb))
sudo_fatal("%s: stat(%s)", kind, path);
if (fd >= 0) {
if (fstat(fd, &fsb))
sudo_fatal("%s: fstat(%d==%s)", kind, fd, path);
if (sb.st_dev != fsb.st_dev || sb.st_ino != fsb.st_ino)
sudo_fatalx("%s: stat mismatch", kind);
}
if (memcmp(path, prefix, plen) != 0)
sudo_fatalx("%s: prefix changed! %s vs %s", kind, prefix, path);
if (memcmp(path + plen + tlen, suffix, slen + 1) != 0)
sudo_fatalx("%s: suffix changed! %s vs %s", kind, suffix, path);
for (p = path + plen; p < path + plen + tlen; p++)
if (*p == '\0')
sudo_fatalx("%s: unexpected truncation", kind);
else if (*p == 'X')
return 0;
return 1;
}
static void
try_mkdtemp(char *p, char const *prefix, int len)
{
size_t plen = strlen(prefix);
int fd, tries, ok;
for (tries = 0; tries < MAX_TRIES; tries++) {
memcpy(p, prefix, plen);
memset(p + plen, 'X', len);
p[plen + len] = '\0';
fd = mkdtemp(p) ? -2 : -1;
ok = check(fd, "mkdtemp", p, prefix, plen, "", 0, len);
rmdir(p);
if (ok)
return;
}
sudo_fatalx("mkdtemp: exceeded MAX_TRIES");
}
static void
try_mkstemps(char *p, char const *prefix, int len, char const *suffix)
{
size_t plen = strlen(prefix);
size_t slen = strlen(suffix);
int tries, fd, ok;
for (tries = 0; tries < MAX_TRIES; tries++) {
memcpy(p, prefix, plen);
memset(p + plen, 'X', len);
memcpy(p + plen + len, suffix, slen + 1);
fd = mkstemps(p, slen);
ok = check(fd, "mkstemp", p, prefix, plen, suffix, slen, len);
close(fd);
unlink(p);
if (ok)
return;
}
sudo_fatalx("mkstemps: exceeded MAX_TRIES");
}
int
main(int argc, char *argv[])
{
char cwd[PATH_MAX + 1];
char *p;
size_t clen;
long pg;
int ch, i;
initprogname(argc > 0 ? argv[0] : "mktemp_test");
while ((ch = getopt(argc, argv, "v")) != -1) {
switch (ch) {
case 'v':
/* ignore */
break;
default:
fprintf(stderr, "usage: %s [-v]\n", getprogname());
return EXIT_FAILURE;
}
}
argc -= optind;
argv += optind;
pg = sysconf(_SC_PAGESIZE);
if (getcwd(cwd, sizeof cwd - 1) == NULL)
sudo_fatal("getcwd");
clen = strlen(cwd);
cwd[clen++] = '/';
cwd[clen] = '\0';
#ifdef MAP_ANON
p = mmap(NULL, pg * 3, PROT_READ | PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0);
#else
i = open("/dev/zero", O_RDWR);
if (i == -1)
sudo_fatal("/dev/zero");
p = mmap(NULL, pg * 3, PROT_READ | PROT_WRITE, MAP_PRIVATE, i, 0);
#endif
if (p == MAP_FAILED)
sudo_fatal("mmap");
if (mprotect(p, pg, PROT_NONE) || mprotect(p + pg * 2, pg, PROT_NONE))
sudo_fatal("mprotect");
p += pg;
i = MAX_TEMPLATE_LEN + 1;
while (i-- > 0) {
/* try first at the start of a page, no prefix */
try_mkdtemp(p, "", i);
/* now at the end of the page, no prefix */
try_mkdtemp(p + pg - i - 1, "", i);
/* start of the page, prefixed with the cwd */
try_mkdtemp(p, cwd, i);
/* how about at the end of the page, prefixed with cwd? */
try_mkdtemp(p + pg - clen - i - 1, cwd, i);
/* again, with mkstemps() and an empty suffix */
/* try first at the start of a page, no prefix */
try_mkstemps(p, "", i, "");
/* now at the end of the page, no prefix */
try_mkstemps(p + pg - i - 1, "", i, "");
/* start of the page, prefixed with the cwd */
try_mkstemps(p, cwd, i, "");
/* how about at the end of the page, prefixed with cwd? */
try_mkstemps(p + pg - clen - i - 1, cwd, i, "");
/* mkstemps() and a non-empty suffix */
/* try first at the start of a page, no prefix */
try_mkstemps(p, "", i, SUFFIX);
/* now at the end of the page, no prefix */
try_mkstemps(p + pg - i - SLEN - 1, "", i, SUFFIX);
/* start of the page, prefixed with the cwd */
try_mkstemps(p, cwd, i, SUFFIX);
/* how about at the end of the page, prefixed with cwd? */
try_mkstemps(p + pg - clen - i - SLEN - 1, cwd, i, SUFFIX);
}
return 0;
}
|
