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
|
/*
* Copyright (C) 2014-2024 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/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <dirent.h>
static int tmpfs_mounted = 0;
// build /run/firejail directory
void preproc_build_firejail_dir(void) {
struct stat s;
// CentOS 6 doesn't have /run directory
if (stat(RUN_FIREJAIL_BASEDIR, &s)) {
create_empty_dir_as_root(RUN_FIREJAIL_BASEDIR, 0755);
}
create_empty_dir_as_root(RUN_FIREJAIL_DIR, 0755);
create_empty_dir_as_root(RUN_FIREJAIL_NETWORK_DIR, 0755);
create_empty_dir_as_root(RUN_FIREJAIL_BANDWIDTH_DIR, 0755);
create_empty_dir_as_root(RUN_FIREJAIL_NAME_DIR, 0755);
create_empty_dir_as_root(RUN_FIREJAIL_PROFILE_DIR, 0755);
create_empty_dir_as_root(RUN_FIREJAIL_X11_DIR, 0755);
create_empty_dir_as_root(RUN_FIREJAIL_APPIMAGE_DIR, 0755);
create_empty_dir_as_root(RUN_FIREJAIL_LIB_DIR, 0755);
create_empty_dir_as_root(RUN_MNT_DIR, 0755);
// restricted search permission
// only root should be able to lock files in this directory
create_empty_dir_as_root(RUN_FIREJAIL_SANDBOX_DIR, 0700);
create_empty_dir_as_root(RUN_FIREJAIL_DBUS_DIR, 0755);
fs_remount(RUN_FIREJAIL_DBUS_DIR, MOUNT_NOEXEC, 0);
create_empty_dir_as_root(RUN_RO_DIR, S_IRUSR);
fs_remount(RUN_RO_DIR, MOUNT_READONLY, 0);
create_empty_file_as_root(RUN_RO_FILE, S_IRUSR);
fs_remount(RUN_RO_FILE, MOUNT_READONLY, 0);
}
// build /run/firejail/mnt directory
void preproc_mount_mnt_dir(void) {
// mount tmpfs on top of /run/firejail/mnt
if (!tmpfs_mounted) {
if (arg_debug)
printf("Mounting tmpfs on %s directory\n", RUN_MNT_DIR);
if (mount("tmpfs", RUN_MNT_DIR, "tmpfs", MS_NOSUID | MS_STRICTATIME, "mode=755,gid=0") < 0)
errExit("mounting /run/firejail/mnt");
tmpfs_mounted = 1;
fs_logger2("tmpfs", RUN_MNT_DIR);
// open and mount trace file while there are no user-writable files in RUN_MNT_DIR
if (arg_tracefile)
fs_tracefile();
create_empty_dir_as_root(RUN_SECCOMP_DIR, 0755);
if (arg_seccomp_block_secondary)
copy_file(PATH_SECCOMP_BLOCK_SECONDARY, RUN_SECCOMP_BLOCK_SECONDARY, getuid(), getgid(), 0644); // root needed
else {
//copy default seccomp files
copy_file(PATH_SECCOMP_32, RUN_SECCOMP_32, getuid(), getgid(), 0644); // root needed
}
if (arg_allow_debuggers) {
copy_file(PATH_SECCOMP_DEFAULT_DEBUG, RUN_SECCOMP_CFG, getuid(), getgid(), 0644); // root needed
copy_file(PATH_SECCOMP_DEBUG_32, RUN_SECCOMP_32, getuid(), getgid(), 0644); // root needed
} else
copy_file(PATH_SECCOMP_DEFAULT, RUN_SECCOMP_CFG, getuid(), getgid(), 0644); // root needed
if (arg_memory_deny_write_execute) {
copy_file(PATH_SECCOMP_MDWX, RUN_SECCOMP_MDWX, getuid(), getgid(), 0644); // root needed
copy_file(PATH_SECCOMP_MDWX_32, RUN_SECCOMP_MDWX_32, getuid(), getgid(), 0644); // root needed
}
// as root, create empty RUN_SECCOMP_PROTOCOL, RUN_SECCOMP_NS and RUN_SECCOMP_POSTEXEC files
create_empty_file_as_root(RUN_SECCOMP_PROTOCOL, 0644);
if (set_perms(RUN_SECCOMP_PROTOCOL, getuid(), getgid(), 0644))
errExit("set_perms");
if (cfg.restrict_namespaces) {
copy_file(PATH_SECCOMP_NAMESPACES, RUN_SECCOMP_NS, getuid(), getgid(), 0644); // root needed
copy_file(PATH_SECCOMP_NAMESPACES_32, RUN_SECCOMP_NS_32, getuid(), getgid(), 0644); // root needed
#if 0
create_empty_file_as_root(RUN_SECCOMP_NS, 0644);
if (set_perms(RUN_SECCOMP_NS, getuid(), getgid(), 0644))
errExit("set_perms");
create_empty_file_as_root(RUN_SECCOMP_NS_32, 0644);
if (set_perms(RUN_SECCOMP_NS_32, getuid(), getgid(), 0644))
errExit("set_perms");
#endif
}
create_empty_file_as_root(RUN_SECCOMP_POSTEXEC, 0644);
if (set_perms(RUN_SECCOMP_POSTEXEC, getuid(), getgid(), 0644))
errExit("set_perms");
create_empty_file_as_root(RUN_SECCOMP_POSTEXEC_32, 0644);
if (set_perms(RUN_SECCOMP_POSTEXEC_32, getuid(), getgid(), 0644))
errExit("set_perms");
}
}
static void clean_dir(const char *name, int *pidarr, int start_pid, int max_pids) {
DIR *dir;
if (!(dir = opendir(name))) {
fwarning("cannot clean %s directory\n", name);
return; // we live to fight another day!
}
// clean leftover files
struct dirent *entry;
char *end;
while ((entry = readdir(dir)) != NULL) {
pid_t pid = strtol(entry->d_name, &end, 10);
pid %= max_pids;
if (end == entry->d_name || *end)
continue;
if (pid < start_pid)
continue;
if (pidarr[pid] == 0)
delete_run_files(pid);
}
closedir(dir);
}
// clean run directory
void preproc_clean_run(void) {
int max_pids=32769;
int start_pid = 100;
// extract real max_pids
FILE *fp = fopen("/proc/sys/kernel/pid_max", "re");
if (fp) {
int val;
if (fscanf(fp, "%d", &val) == 1) {
if (val > 4194304) // this is the max value supported on 64 bit Linux kernels
val = 4194304;
if (val >= max_pids)
max_pids = val + 1;
}
fclose(fp);
}
int *pidarr = malloc(max_pids * sizeof(int));
if (!pidarr)
errExit("malloc");
memset(pidarr, 0, max_pids * sizeof(int));
// open /proc directory
DIR *dir;
if (!(dir = opendir("/proc"))) {
// sleep 2 seconds and try again
sleep(2);
if (!(dir = opendir("/proc"))) {
fprintf(stderr, "Error: cannot open /proc directory\n");
exit(1);
}
}
// read /proc and populate pidarr with all active processes
struct dirent *entry;
char *end;
while ((entry = readdir(dir)) != NULL) {
pid_t pid = strtol(entry->d_name, &end, 10);
pid %= max_pids;
if (end == entry->d_name || *end)
continue;
if (pid < start_pid)
continue;
pidarr[pid] = 1;
}
closedir(dir);
// clean profile and name directories
clean_dir(RUN_FIREJAIL_PROFILE_DIR, pidarr, start_pid, max_pids);
clean_dir(RUN_FIREJAIL_NAME_DIR, pidarr, start_pid, max_pids);
free(pidarr);
}
|
