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
|
/*
* Copyright (C) 2014-2016 Firejail Authors
*
* This file is part of firejail project
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "firejail.h"
#include <sys/stat.h>
#define MAXBUF 4096
void save_cgroup(void) {
if (cfg.cgroup == NULL)
return;
FILE *fp = fopen(RUN_CGROUP_CFG, "w");
if (fp) {
fprintf(fp, "%s", cfg.cgroup);
fflush(0);
if (fclose(fp))
goto errout;
if (chown(RUN_CGROUP_CFG, 0, 0) < 0)
errExit("chown");
}
else
goto errout;
return;
errout:
fprintf(stderr, "Error: cannot save cgroup\n");
exit(1);
}
void load_cgroup(const char *fname) {
if (!fname)
return;
FILE *fp = fopen(fname, "r");
if (fp) {
char buf[MAXBUF];
if (fgets(buf, MAXBUF, fp)) {
cfg.cgroup = strdup(buf);
if (!cfg.cgroup)
errExit("strdup");
}
else
goto errout;
fclose(fp);
return;
}
errout:
fprintf(stderr, "Warning: cannot load control group\n");
if (fp)
fclose(fp);
}
void set_cgroup(const char *path) {
EUID_ASSERT();
invalid_filename(path);
// path starts with /sys/fs/cgroup
if (strncmp(path, "/sys/fs/cgroup", 14) != 0)
goto errout;
// path ends in tasks
char *ptr = strstr(path, "tasks");
if (!ptr)
goto errout;
if (*(ptr + 5) != '\0')
goto errout;
// no .. traversal
ptr = strstr(path, "..");
if (ptr)
goto errout;
// tasks file exists
struct stat s;
if (stat(path, &s) == -1)
goto errout;
// task file belongs to the user running the sandbox
if (s.st_uid != getuid() && s.st_gid != getgid())
goto errout2;
// add the task to cgroup
/* coverity[toctou] */
FILE *fp = fopen(path, "a");
if (!fp)
goto errout;
pid_t pid = getpid();
int rv = fprintf(fp, "%d\n", pid);
(void) rv;
fclose(fp);
return;
errout:
fprintf(stderr, "Error: invalid cgroup\n");
exit(1);
errout2:
fprintf(stderr, "Error: you don't have permissions to use this control group\n");
exit(1);
}
|