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/*
* Copyright (C) 2014-2021 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/types.h>
#include <sys/stat.h>
#include <sys/statvfs.h>
#include <sys/mount.h>
#include <dirent.h>
#include <errno.h>
#include <sys/wait.h>
#include <fcntl.h>
#ifndef O_PATH
#define O_PATH 010000000
#endif
#define PULSE_CLIENT_SYSCONF "/etc/pulse/client.conf"
// disable pulseaudio socket
void pulseaudio_disable(void) {
if (arg_debug)
printf("disable pulseaudio\n");
// blacklist user config directory
disable_file_path(cfg.homedir, ".config/pulse");
// blacklist pulseaudio socket in XDG_RUNTIME_DIR
const char *name = env_get("XDG_RUNTIME_DIR");
if (name)
disable_file_path(name, "pulse/native");
// try the default location anyway
char *path;
if (asprintf(&path, "/run/user/%d", getuid()) == -1)
errExit("asprintf");
disable_file_path(path, "pulse");
free(path);
// blacklist any pulse* file in /tmp directory
DIR *dir;
if (!(dir = opendir("/tmp"))) {
// sleep 2 seconds and try again
sleep(2);
if (!(dir = opendir("/tmp"))) {
return;
}
}
struct dirent *entry;
while ((entry = readdir(dir))) {
if (strncmp(entry->d_name, "pulse-", 6) == 0) {
disable_file_path("/tmp", entry->d_name);
}
}
closedir(dir);
}
static void pulseaudio_fallback(const char *path) {
assert(path);
fmessage("Cannot mount tmpfs on %s/.config/pulse\n", cfg.homedir);
env_store_name_val("PULSE_CLIENTCONFIG", path, SETENV);
}
// disable shm in pulseaudio (issue #69)
void pulseaudio_init(void) {
struct stat s;
// do we have pulseaudio in the system?
if (stat(PULSE_CLIENT_SYSCONF, &s) == -1) {
if (arg_debug)
printf("%s not found\n", PULSE_CLIENT_SYSCONF);
return;
}
// create the new user pulseaudio directory
if (mkdir(RUN_PULSE_DIR, 0700) == -1)
errExit("mkdir");
selinux_relabel_path(RUN_PULSE_DIR, RUN_PULSE_DIR);
// mount it nosuid, noexec, nodev
fs_remount(RUN_PULSE_DIR, MOUNT_NOEXEC, 0);
// create the new client.conf file
char *pulsecfg = NULL;
if (asprintf(&pulsecfg, "%s/client.conf", RUN_PULSE_DIR) == -1)
errExit("asprintf");
if (copy_file(PULSE_CLIENT_SYSCONF, pulsecfg, -1, -1, 0644)) // root needed
errExit("copy_file");
FILE *fp = fopen(pulsecfg, "ae");
if (!fp)
errExit("fopen");
fprintf(fp, "%s", "\nenable-shm = no\n");
SET_PERMS_STREAM(fp, getuid(), getgid(), 0644);
fclose(fp);
// hand over the directory to the user
if (set_perms(RUN_PULSE_DIR, getuid(), getgid(), 0700))
errExit("set_perms");
// create ~/.config/pulse directory if not present
char *homeusercfg = NULL;
if (asprintf(&homeusercfg, "%s/.config", cfg.homedir) == -1)
errExit("asprintf");
if (create_empty_dir_as_user(homeusercfg, 0700))
fs_logger2("create", homeusercfg);
free(homeusercfg);
if (asprintf(&homeusercfg, "%s/.config/pulse", cfg.homedir) == -1)
errExit("asprintf");
if (create_empty_dir_as_user(homeusercfg, 0700))
fs_logger2("create", homeusercfg);
// if ~/.config/pulse exists and there are no symbolic links, mount the new directory
// else set environment variable
int fd = safer_openat(-1, homeusercfg, O_PATH|O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC);
if (fd == -1) {
pulseaudio_fallback(pulsecfg);
goto out;
}
// confirm the actual mount destination is owned by the user
if (fstat(fd, &s) == -1) { // FUSE
if (errno != EACCES)
errExit("fstat");
close(fd);
pulseaudio_fallback(pulsecfg);
goto out;
}
if (s.st_uid != getuid()) {
close(fd);
pulseaudio_fallback(pulsecfg);
goto out;
}
// preserve a read-only mount
struct statvfs vfs;
if (fstatvfs(fd, &vfs) == -1)
errExit("fstatvfs");
if ((vfs.f_flag & MS_RDONLY) == MS_RDONLY)
fs_remount(RUN_PULSE_DIR, MOUNT_READONLY, 0);
// mount via the link in /proc/self/fd
if (arg_debug)
printf("Mounting %s on %s\n", RUN_PULSE_DIR, homeusercfg);
if (bind_mount_path_to_fd(RUN_PULSE_DIR, fd))
errExit("mount pulseaudio");
// check /proc/self/mountinfo to confirm the mount is ok
MountData *mptr = get_last_mount();
if (strcmp(mptr->dir, homeusercfg) != 0 || strcmp(mptr->fstype, "tmpfs") != 0)
errLogExit("invalid pulseaudio mount");
fs_logger2("tmpfs", homeusercfg);
close(fd);
char *p;
if (asprintf(&p, "%s/client.conf", homeusercfg) == -1)
errExit("asprintf");
env_store_name_val("PULSE_CLIENTCONFIG", p, SETENV);
fs_logger2("create", p);
free(p);
// RUN_PULSE_DIR not needed anymore, mask it
if (mount("tmpfs", RUN_PULSE_DIR, "tmpfs", MS_NOSUID | MS_NODEV | MS_STRICTATIME, "mode=755,gid=0") < 0)
errExit("mount pulseaudio");
fs_logger2("tmpfs", RUN_PULSE_DIR);
out:
free(pulsecfg);
free(homeusercfg);
}
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