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/*
* Copyright (C) 2014, 2015 netblue30 (netblue30@yahoo.com)
*
* 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 <linux/limits.h>
#include <glob.h>
#include <dirent.h>
#include <fcntl.h>
#include <pwd.h>
#ifndef _BSD_SOURCE
#define _BSD_SOURCE
#endif
#include <sys/types.h>
static void create_char_dev(const char *path, mode_t mode, int major, int minor) {
dev_t dev = makedev(major, minor);
int rv = mknod(path, S_IFCHR | mode, dev);
if (rv == -1)
goto errexit;
if (chmod(path, mode) < 0)
goto errexit;
if (chown(path, 0, 0) < 0)
goto errexit;
return;
errexit:
fprintf(stderr, "Error: cannot create %s device\n", path);
exit(1);
}
static void create_link(const char *oldpath, const char *newpath) {
if (symlink(oldpath, newpath) == -1)
goto errexit;
if (chown(newpath, 0, 0) < 0)
goto errexit;
return;
errexit:
fprintf(stderr, "Error: cannot create %s device\n", newpath);
exit(1);
}
void fs_private_dev(void){
// install a new /dev directory
if (arg_debug)
printf("Mounting tmpfs on /dev\n");
if (mount("tmpfs", "/dev", "tmpfs", MS_NOSUID | MS_STRICTATIME | MS_REC, "mode=777,gid=0") < 0)
errExit("mounting /dev");
// create /dev/shm
if (arg_debug)
printf("Create /dev/shm directory\n");
int rv = mkdir("/dev/shm", S_IRWXU | S_IRWXG | S_IRWXO);
if (rv == -1)
errExit("mkdir");
if (chown("/dev/shm", 0, 0) < 0)
errExit("chown");
if (chmod("/dev/shm", S_IRWXU | S_IRWXG | S_IRWXO) < 0)
errExit("chmod");
// create devices
create_char_dev("/dev/zero", 0666, 1, 5); // mknod -m 666 /dev/zero c 1 5
create_char_dev("/dev/null", 0666, 1, 3); // mknod -m 666 /dev/null c 1 3
create_char_dev("/dev/full", 0666, 1, 7); // mknod -m 666 /dev/full c 1 7
create_char_dev("/dev/random", 0666, 1, 8); // Mknod -m 666 /dev/random c 1 8
create_char_dev("/dev/urandom", 0666, 1, 9); // mknod -m 666 /dev/urandom c 1 9
create_char_dev("/dev/tty", 0666, 5, 0); // mknod -m 666 /dev/tty c 5 0
#if 0
create_dev("/dev/tty0", "mknod -m 666 /dev/tty0 c 4 0");
create_dev("/dev/console", "mknod -m 622 /dev/console c 5 1");
#endif
// pseudo-terminal
rv = mkdir("/dev/pts", 0755);
if (rv == -1)
errExit("mkdir");
if (chown("/dev/pts", 0, 0) < 0)
errExit("chown");
if (chmod("/dev/pts", 0755) < 0)
errExit("chmod");
create_char_dev("/dev/pts/ptmx", 0666, 5, 2); //"mknod -m 666 /dev/pts/ptmx c 5 2");
create_link("/dev/pts/ptmx", "/dev/ptmx");
// mount -vt devpts -o newinstance -o ptmxmode=0666 devpts //dev/pts
if (mount("devpts", "/dev/pts", "devpts", MS_MGC_VAL, "newinstance,ptmxmode=0666") < 0)
errExit("mounting /dev/pts");
#if 0
// stdin, stdout, stderr
create_link("/proc/self/fd", "/dev/fd");
create_link("/proc/self/fd/0", "/dev/stdin");
create_link("/proc/self/fd/1", "/dev/stdout");
create_link("/proc/self/fd/2", "/dev/stderr");
#endif
}
void fs_dev_shm(void) {
uid_t uid = getuid(); // set a new shm only if we started as root
if (uid)
return;
if (is_dir("/dev/shm")) {
if (arg_debug)
printf("Mounting tmpfs on /dev/shm\n");
if (mount("tmpfs", "/dev/shm", "tmpfs", MS_NOSUID | MS_STRICTATIME | MS_REC, "mode=777,gid=0") < 0)
errExit("mounting /dev/shm");
}
else {
char *lnk = get_link("/dev/shm");
if (lnk) {
// convert a link such as "../shm" into "/shm"
char *lnk2 = lnk;
int cnt = 0;
while (strncmp(lnk2, "../", 3) == 0) {
cnt++;
lnk2 = lnk2 + 3;
}
if (cnt != 0)
lnk2 = lnk + (cnt - 1) * 3 + 2;
if (!is_dir(lnk2)) {
// create directory
if (mkdir(lnk2, S_IRWXU|S_IRWXG|S_IRWXO))
errExit("mkdir");
if (chown(lnk2, 0, 0))
errExit("chown");
if (chmod(lnk2, S_IRWXU|S_IRWXG|S_IRWXO))
errExit("chmod");
}
if (arg_debug)
printf("Mounting tmpfs on %s on behalf of /dev/shm\n", lnk2);
if (mount("tmpfs", lnk2, "tmpfs", MS_NOSUID | MS_STRICTATIME | MS_REC, "mode=777,gid=0") < 0)
errExit("mounting /var/tmp");
free(lnk);
}
else {
fprintf(stderr, "Warning: /dev/shm not mounted\n");
dbg_test_dir("/dev/shm");
}
}
}
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