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/*
* Copyright (C) 2014-2018 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.
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <sys/syscall.h>
#include <errno.h>
#include <unistd.h>
#include <sys/prctl.h>
#include <signal.h>
#include <dirent.h>
#include <string.h>
#include "../include/common.h"
#define BUFLEN 4096
int join_namespace(pid_t pid, char *type) {
char *path;
if (asprintf(&path, "/proc/%u/ns/%s", pid, type) == -1)
errExit("asprintf");
int fd = open(path, O_RDONLY);
if (fd < 0)
goto errout;
if (syscall(__NR_setns, fd, 0) < 0) {
close(fd);
goto errout;
}
close(fd);
free(path);
return 0;
errout:
free(path);
fprintf(stderr, "Error: cannot join namespace %s\\n", type);
return -1;
}
// return 1 if error
// this function requires root access - todo: fix it!
int name2pid(const char *name, pid_t *pid) {
pid_t parent = getpid();
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);
}
}
struct dirent *entry;
char *end;
while ((entry = readdir(dir))) {
pid_t newpid = strtol(entry->d_name, &end, 10);
if (end == entry->d_name || *end)
continue;
if (newpid == parent)
continue;
// check if this is a firejail executable
char *comm = pid_proc_comm(newpid);
if (comm) {
if (strcmp(comm, "firejail")) {
free(comm);
continue;
}
free(comm);
}
// look for the sandbox name in /run/firejail/name/<PID>
// todo: use RUN_FIREJAIL_NAME_DIR define from src/firejail/firejail.h
char *fname;
if (asprintf(&fname, "/run/firejail/name/%d", newpid) == -1)
errExit("asprintf");
FILE *fp = fopen(fname, "r");
if (fp) {
char buf[BUFLEN];
if (fgets(buf, BUFLEN, fp)) {
// remove \n
char *ptr = strchr(buf, '\n');
if (ptr) {
*ptr = '\0';
if (strcmp(buf, name) == 0) {
// we found it!
fclose(fp);
free(fname);
*pid = newpid;
closedir(dir);
return 0;
}
}
else
fprintf(stderr, "Error: invalid %s\n", fname);
}
fclose(fp);
}
free(fname);
}
closedir(dir);
return 1;
}
char *pid_proc_comm(const pid_t pid) {
// open /proc/pid/cmdline file
char *fname;
int fd;
if (asprintf(&fname, "/proc/%d/comm", pid) == -1)
return NULL;
if ((fd = open(fname, O_RDONLY)) < 0) {
free(fname);
return NULL;
}
free(fname);
// read file
char buffer[BUFLEN];
ssize_t len;
if ((len = read(fd, buffer, sizeof(buffer) - 1)) <= 0) {
close(fd);
return NULL;
}
buffer[len] = '\0';
close(fd);
// remove \n
char *ptr = strchr(buffer, '\n');
if (ptr)
*ptr = '\0';
// return a malloc copy of the command line
char *rv = strdup(buffer);
if (!rv)
return NULL;
if (strlen(rv) == 0) {
free(rv);
return NULL;
}
return rv;
}
char *pid_proc_cmdline(const pid_t pid) {
// open /proc/pid/cmdline file
char *fname;
int fd;
if (asprintf(&fname, "/proc/%d/cmdline", pid) == -1)
return NULL;
if ((fd = open(fname, O_RDONLY)) < 0) {
free(fname);
return NULL;
}
free(fname);
// read file
unsigned char buffer[BUFLEN];
ssize_t len;
if ((len = read(fd, buffer, sizeof(buffer) - 1)) <= 0) {
close(fd);
return NULL;
}
buffer[len] = '\0';
close(fd);
// clean data
int i;
for (i = 0; i < len; i++) {
if (buffer[i] == '\0')
buffer[i] = ' ';
}
// return a malloc copy of the command line
char *rv = strdup((char *) buffer);
if (!rv)
return NULL;
if (strlen(rv) == 0) {
free(rv);
return NULL;
}
return rv;
}
// return 1 if firejail --x11 on command line
int pid_proc_cmdline_x11_xpra_xephyr(const pid_t pid) {
// if comm is not firejail return 0
char *comm = pid_proc_comm(pid);
if (comm == NULL)
return 0;
if (strcmp(comm, "firejail") != 0) {
free(comm);
return 0;
}
free(comm);
// open /proc/pid/cmdline file
char *fname;
int fd;
if (asprintf(&fname, "/proc/%d/cmdline", pid) == -1)
return 0;
if ((fd = open(fname, O_RDONLY)) < 0) {
free(fname);
return 0;
}
free(fname);
// read file
unsigned char buffer[BUFLEN];
ssize_t len;
if ((len = read(fd, buffer, sizeof(buffer) - 1)) <= 0) {
close(fd);
return 0;
}
buffer[len] = '\0';
close(fd);
// skip the first argument
int i;
for (i = 0; buffer[i] != '\0'; i++);
// parse remaining command line options
while (1) {
// extract argument
i++;
if (i >= len)
break;
char *arg = (char *)buffer + i;
// detect the last command line option
if (strcmp(arg, "--") == 0)
break;
if (strncmp(arg, "--", 2) != 0)
break;
if (strcmp(arg, "--x11=xorg") == 0 || strcmp(arg, "--x11=none") == 0)
return 0;
// check x11 xpra or xephyr
if (strncmp(arg, "--x11", 5) == 0)
return 1;
i += strlen(arg);
}
return 0;
}
// return 1 if /proc is mounted hidepid, or if /proc/mouns access is denied
#define BUFLEN 4096
int pid_hidepid(void) {
FILE *fp = fopen("/proc/mounts", "r");
if (!fp)
return 1;
char buf[BUFLEN];
while (fgets(buf, BUFLEN, fp)) {
if (strstr(buf, "proc /proc proc")) {
fclose(fp);
// check hidepid
if (strstr(buf, "hidepid=2") || strstr(buf, "hidepid=1"))
return 1;
return 0;
}
}
fclose(fp);
return 0;
}
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