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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 <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
static char *client_filter =
"*filter\n"
":INPUT DROP [0:0]\n"
":FORWARD DROP [0:0]\n"
":OUTPUT ACCEPT [0:0]\n"
"-A INPUT -i lo -j ACCEPT\n"
"-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT\n"
"# echo replay is handled by -m state RELATED/ESTABLISHED below\n"
"#-A INPUT -p icmp --icmp-type echo-reply -j ACCEPT\n"
"-A INPUT -p icmp --icmp-type destination-unreachable -j ACCEPT\n"
"-A INPUT -p icmp --icmp-type time-exceeded -j ACCEPT\n"
"-A INPUT -p icmp --icmp-type echo-request -j ACCEPT \n"
"# disable STUN\n"
"-A OUTPUT -p udp --dport 3478 -j DROP\n"
"-A OUTPUT -p udp --dport 3479 -j DROP\n"
"-A OUTPUT -p tcp --dport 3478 -j DROP\n"
"-A OUTPUT -p tcp --dport 3479 -j DROP\n"
"COMMIT\n";
void check_netfilter_file(const char *fname) {
EUID_ASSERT();
invalid_filename(fname);
if (is_dir(fname) || is_link(fname) || strstr(fname, "..")) {
fprintf(stderr, "Error: invalid network filter file\n");
exit(1);
}
// access call checks as real UID/GID, not as effective UID/GID
if (access(fname, R_OK)) {
fprintf(stderr, "Error: cannot access network filter file\n");
exit(1);
}
}
void netfilter(const char *fname) {
// find iptables command
struct stat s;
char *iptables = NULL;
char *iptables_restore = NULL;
if (stat("/sbin/iptables", &s) == 0) {
iptables = "/sbin/iptables";
iptables_restore = "/sbin/iptables-restore";
}
else if (stat("/usr/sbin/iptables", &s) == 0) {
iptables = "/usr/sbin/iptables";
iptables_restore = "/usr/sbin/iptables-restore";
}
if (iptables == NULL || iptables_restore == NULL) {
fprintf(stderr, "Error: iptables command not found, netfilter not configured\n");
return;
}
// read filter
char *filter = client_filter;
int allocated = 0;
if (netfilter_default)
fname = netfilter_default;
if (fname) {
filter = read_text_file_or_exit(fname);
allocated = 1;
}
// create the filter file
FILE *fp = fopen(SBOX_STDIN_FILE, "w");
if (!fp) {
fprintf(stderr, "Error: cannot open %s\n", SBOX_STDIN_FILE);
exit(1);
}
fprintf(fp, "%s\n", filter);
fclose(fp);
// push filter
if (arg_debug)
printf("Installing network filter:\n%s\n", filter);
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP | SBOX_STDIN_FROM_FILE, 1, iptables_restore);
unlink(SBOX_STDIN_FILE);
// debug
if (arg_debug)
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP, 2, iptables, "-vL");
if (allocated)
free(filter);
return;
}
void netfilter6(const char *fname) {
if (fname == NULL)
return;
// find iptables command
char *ip6tables = NULL;
char *ip6tables_restore = NULL;
struct stat s;
if (stat("/sbin/ip6tables", &s) == 0) {
ip6tables = "/sbin/ip6tables";
ip6tables_restore = "/sbin/ip6tables-restore";
}
else if (stat("/usr/sbin/ip6tables", &s) == 0) {
ip6tables = "/usr/sbin/ip6tables";
ip6tables_restore = "/usr/sbin/ip6tables-restore";
}
if (ip6tables == NULL || ip6tables_restore == NULL) {
fprintf(stderr, "Error: ip6tables command not found, netfilter6 not configured\n");
return;
}
// create the filter file
char *filter = read_text_file_or_exit(fname);
FILE *fp = fopen(SBOX_STDIN_FILE, "w");
if (!fp) {
fprintf(stderr, "Error: cannot open /tmp/netfilter6 file\n");
exit(1);
}
fprintf(fp, "%s\n", filter);
fclose(fp);
// push filter
if (arg_debug)
printf("Installing network filter:\n%s\n", filter);
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP | SBOX_STDIN_FROM_FILE, 1, ip6tables_restore);
unlink(SBOX_STDIN_FILE);
// debug
if (arg_debug)
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP, 2, ip6tables, "-vL");
free(filter);
return;
}
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