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/*
* 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/mount.h>
#include <linux/limits.h>
#include <glob.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include <grp.h>
static void skel(const char *homedir, uid_t u, gid_t g) {
char *fname;
// zsh
if (arg_zsh) {
// copy skel files
if (asprintf(&fname, "%s/.zshrc", homedir) == -1)
errExit("asprintf");
struct stat s;
// don't copy it if we already have the file
if (stat(fname, &s) == 0)
return;
if (stat("/etc/skel/.zshrc", &s) == 0) {
if (is_link("/etc/skel/.zshrc")) {
fprintf(stderr, "Error: invalid /etc/skel/.zshrc file\n");
exit(1);
}
if (copy_file("/etc/skel/.zshrc", fname) == 0) {
if (chown(fname, u, g) == -1)
errExit("chown");
fs_logger("clone /etc/skel/.zshrc");
}
}
else { //
FILE *fp = fopen(fname, "w");
if (fp) {
fprintf(fp, "\n");
fclose(fp);
if (chown(fname, u, g) == -1)
errExit("chown");
if (chmod(fname, S_IRUSR | S_IWUSR) < 0)
errExit("chown");
fs_logger2("touch", fname);
}
}
free(fname);
}
// csh
else if (arg_csh) {
// copy skel files
if (asprintf(&fname, "%s/.cshrc", homedir) == -1)
errExit("asprintf");
struct stat s;
// don't copy it if we already have the file
if (stat(fname, &s) == 0)
return;
if (stat("/etc/skel/.cshrc", &s) == 0) {
if (is_link("/etc/skel/.cshrc")) {
fprintf(stderr, "Error: invalid /etc/skel/.cshrc file\n");
exit(1);
}
if (copy_file("/etc/skel/.cshrc", fname) == 0) {
if (chown(fname, u, g) == -1)
errExit("chown");
fs_logger("clone /etc/skel/.cshrc");
}
}
else { //
/* coverity[toctou] */
FILE *fp = fopen(fname, "w");
if (fp) {
fprintf(fp, "\n");
fclose(fp);
if (chown(fname, u, g) == -1)
errExit("chown");
if (chmod(fname, S_IRUSR | S_IWUSR) < 0)
errExit("chown");
fs_logger2("touch", fname);
}
}
free(fname);
}
// bash etc.
else {
// copy skel files
if (asprintf(&fname, "%s/.bashrc", homedir) == -1)
errExit("asprintf");
struct stat s;
// don't copy it if we already have the file
if (stat(fname, &s) == 0)
return;
if (stat("/etc/skel/.bashrc", &s) == 0) {
if (is_link("/etc/skel/.bashrc")) {
fprintf(stderr, "Error: invalid /etc/skel/.bashrc file\n");
exit(1);
}
if (copy_file("/etc/skel/.bashrc", fname) == 0) {
/* coverity[toctou] */
if (chown(fname, u, g) == -1)
errExit("chown");
fs_logger("clone /etc/skel/.bashrc");
}
}
free(fname);
}
}
static int store_xauthority(void) {
// put a copy of .Xauthority in XAUTHORITY_FILE
fs_build_mnt_dir();
char *src;
char *dest = RUN_XAUTHORITY_FILE;
if (asprintf(&src, "%s/.Xauthority", cfg.homedir) == -1)
errExit("asprintf");
struct stat s;
if (stat(src, &s) == 0) {
if (is_link(src)) {
fprintf(stderr, "Error: invalid .Xauthority file\n");
exit(1);
}
int rv = copy_file(src, dest);
if (rv) {
fprintf(stderr, "Warning: cannot transfer .Xauthority in private home directory\n");
return 0;
}
return 1; // file copied
}
return 0;
}
static int store_asoundrc(void) {
// put a copy of .Xauthority in XAUTHORITY_FILE
fs_build_mnt_dir();
char *src;
char *dest = RUN_ASOUNDRC_FILE;
if (asprintf(&src, "%s/.asoundrc", cfg.homedir) == -1)
errExit("asprintf");
struct stat s;
if (stat(src, &s) == 0) {
if (is_link(src)) {
fprintf(stderr, "Error: invalid .asoundrc file\n");
exit(1);
}
int rv = copy_file(src, dest);
if (rv) {
fprintf(stderr, "Warning: cannot transfer .asoundrc in private home directory\n");
return 0;
}
return 1; // file copied
}
return 0;
}
static void copy_xauthority(void) {
// copy XAUTHORITY_FILE in the new home directory
char *src = RUN_XAUTHORITY_FILE ;
char *dest;
if (asprintf(&dest, "%s/.Xauthority", cfg.homedir) == -1)
errExit("asprintf");
int rv = copy_file(src, dest);
if (rv)
fprintf(stderr, "Warning: cannot transfer .Xauthority in private home directory\n");
else {
fs_logger2("clone", dest);
// set permissions and ownership
if (chown(dest, getuid(), getgid()) < 0)
errExit("chown");
if (chmod(dest, S_IRUSR | S_IWUSR) < 0)
errExit("chmod");
}
// delete the temporary file
unlink(src);
}
static void copy_asoundrc(void) {
// copy XAUTHORITY_FILE in the new home directory
char *src = RUN_ASOUNDRC_FILE ;
char *dest;
if (asprintf(&dest, "%s/.asoundrc", cfg.homedir) == -1)
errExit("asprintf");
int rv = copy_file(src, dest);
if (rv)
fprintf(stderr, "Warning: cannot transfer .asoundrc in private home directory\n");
else {
fs_logger2("clone", dest);
// set permissions and ownership
if (chown(dest, getuid(), getgid()) < 0)
errExit("chown");
if (chmod(dest, S_IRUSR | S_IWUSR) < 0)
errExit("chmod");
}
// delete the temporary file
unlink(src);
}
// private mode (--private=homedir):
// mount homedir on top of /home/user,
// tmpfs on top of /root in nonroot mode,
// set skel files,
// restore .Xauthority
void fs_private_homedir(void) {
char *homedir = cfg.homedir;
char *private_homedir = cfg.home_private;
assert(homedir);
assert(private_homedir);
int xflag = store_xauthority();
int aflag = store_asoundrc();
uid_t u = getuid();
gid_t g = getgid();
struct stat s;
if (stat(homedir, &s) == -1) {
fprintf(stderr, "Error: cannot find user home directory\n");
exit(1);
}
// mount bind private_homedir on top of homedir
if (arg_debug)
printf("Mount-bind %s on top of %s\n", private_homedir, homedir);
if (mount(private_homedir, homedir, NULL, MS_BIND|MS_REC, NULL) < 0)
errExit("mount bind");
fs_logger3("mount-bind", private_homedir, cfg.homedir);
fs_logger2("whitelist", cfg.homedir);
// preserve mode and ownership
// if (chown(homedir, s.st_uid, s.st_gid) == -1)
// errExit("mount-bind chown");
// if (chmod(homedir, s.st_mode) == -1)
// errExit("mount-bind chmod");
if (u != 0) {
// mask /root
if (arg_debug)
printf("Mounting a new /root directory\n");
if (mount("tmpfs", "/root", "tmpfs", MS_NOSUID | MS_NODEV | MS_STRICTATIME | MS_REC, "mode=700,gid=0") < 0)
errExit("mounting home directory");
fs_logger("tmpfs /root");
}
else {
// mask /home
if (arg_debug)
printf("Mounting a new /home directory\n");
if (mount("tmpfs", "/home", "tmpfs", MS_NOSUID | MS_NODEV | MS_STRICTATIME | MS_REC, "mode=755,gid=0") < 0)
errExit("mounting home directory");
fs_logger("tmpfs /home");
}
skel(homedir, u, g);
if (xflag)
copy_xauthority();
if (aflag)
copy_asoundrc();
}
// private mode (--private):
// mount tmpfs over /home/user,
// tmpfs on top of /root in nonroot mode,
// set skel files,
// restore .Xauthority
void fs_private(void) {
char *homedir = cfg.homedir;
assert(homedir);
uid_t u = getuid();
gid_t g = getgid();
int xflag = store_xauthority();
int aflag = store_asoundrc();
// mask /home
if (arg_debug)
printf("Mounting a new /home directory\n");
if (mount("tmpfs", "/home", "tmpfs", MS_NOSUID | MS_NODEV | MS_STRICTATIME | MS_REC, "mode=755,gid=0") < 0)
errExit("mounting home directory");
fs_logger("tmpfs /home");
// mask /root
if (arg_debug)
printf("Mounting a new /root directory\n");
if (mount("tmpfs", "/root", "tmpfs", MS_NOSUID | MS_NODEV | MS_STRICTATIME | MS_REC, "mode=700,gid=0") < 0)
errExit("mounting root directory");
fs_logger("tmpfs /root");
if (u != 0) {
// create /home/user
if (arg_debug)
printf("Create a new user directory\n");
if (mkdir(homedir, S_IRWXU) == -1) {
if (mkpath_as_root(homedir) == -1)
errExit("mkpath");
if (mkdir(homedir, S_IRWXU) == -1)
errExit("mkdir");
}
if (chown(homedir, u, g) < 0)
errExit("chown");
fs_logger2("mkdir", homedir);
}
skel(homedir, u, g);
if (xflag)
copy_xauthority();
if (aflag)
copy_asoundrc();
}
// check new private home directory (--private= option) - exit if it fails
void fs_check_private_dir(void) {
EUID_ASSERT();
invalid_filename(cfg.home_private);
// Expand the home directory
char *tmp = expand_home(cfg.home_private, cfg.homedir);
cfg.home_private = realpath(tmp, NULL);
free(tmp);
if (!cfg.home_private
|| !is_dir(cfg.home_private)
|| is_link(cfg.home_private)
|| strstr(cfg.home_private, "..")) {
fprintf(stderr, "Error: invalid private directory\n");
exit(1);
}
// check home directory and chroot home directory have the same owner
struct stat s2;
int rv = stat(cfg.home_private, &s2);
if (rv < 0) {
fprintf(stderr, "Error: cannot find %s directory\n", cfg.home_private);
exit(1);
}
struct stat s1;
rv = stat(cfg.homedir, &s1);
if (rv < 0) {
fprintf(stderr, "Error: cannot find %s directory, full path name required\n", cfg.homedir);
exit(1);
}
if (s1.st_uid != s2.st_uid) {
printf("Error: --private directory should be owned by the current user\n");
exit(1);
}
}
|