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/*
* Copyright (C) 2014-2017 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 <arpa/inet.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <netdb.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <net/route.h>
#include <linux/if_bridge.h>
int net_get_mtu(const char *ifname) {
int mtu = 0;
if (strlen(ifname) > IFNAMSIZ) {
fprintf(stderr, "Error: invalid network device name %s\n", ifname);
exit(1);
}
int s;
struct ifreq ifr;
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
errExit("socket");
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_addr.sa_family = AF_INET;
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
if (ioctl(s, SIOCGIFMTU, (caddr_t)&ifr) == 0)
mtu = ifr.ifr_mtu;
if (arg_debug)
printf("MTU of %s is %d.\n", ifname, ifr.ifr_mtu);
close(s);
return mtu;
}
void net_set_mtu(const char *ifname, int mtu) {
if (strlen(ifname) > IFNAMSIZ) {
fprintf(stderr, "Error: invalid network device name %s\n", ifname);
exit(1);
}
if (arg_debug)
printf("set interface %s MTU %d.\n", ifname, mtu);
int s;
struct ifreq ifr;
if ((s = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
errExit("socket");
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_addr.sa_family = AF_INET;
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
ifr.ifr_mtu = mtu;
if (ioctl(s, SIOCSIFMTU, (caddr_t)&ifr) != 0)
fwarning("cannot set mtu for interface %s\n", ifname);
close(s);
}
// return -1 if the interface was not found; if the interface was found retrn 0 and fill in IP address and mask
int net_get_if_addr(const char *bridge, uint32_t *ip, uint32_t *mask, uint8_t mac[6], int *mtu) {
assert(bridge);
assert(ip);
assert(mask);
if (arg_debug)
printf("get interface %s configuration\n", bridge);
int rv = -1;
struct ifaddrs *ifaddr, *ifa;
if (getifaddrs(&ifaddr) == -1)
errExit("getifaddrs");
// walk through the linked list; if the interface is found, extract IP address and mask
for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr == NULL)
continue;
if (strcmp(ifa->ifa_name, bridge) != 0)
continue;
if (ifa->ifa_addr->sa_family == AF_INET) {
struct sockaddr_in *si = (struct sockaddr_in *) ifa->ifa_netmask;
*mask = ntohl(si->sin_addr.s_addr);
si = (struct sockaddr_in *) ifa->ifa_addr;
*ip = ntohl(si->sin_addr.s_addr);
if (strcmp(ifa->ifa_name, "lo") != 0) {
net_get_mac(ifa->ifa_name, mac);
*mtu = net_get_mtu(bridge);
}
rv = 0;
break;
}
}
freeifaddrs(ifaddr);
return rv;
}
// bring interface up
void net_if_up(const char *ifname) {
if (strlen(ifname) > IFNAMSIZ) {
fprintf(stderr, "Error: invalid network device name %s\n", ifname);
exit(1);
}
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP, 3,
PATH_FNET, "ifup", ifname);
}
// configure interface ipv6 address
// ex: firejail --net=eth0 --ip6=2001:0db8:0:f101::1/64
void net_if_ip6(const char *ifname, const char *addr6) {
if (strchr(addr6, ':') == NULL) {
fprintf(stderr, "Error: invalid IPv6 address %s\n", addr6);
exit(1);
}
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP, 5,
PATH_FNET, "config", "ipv6", ifname, addr6);
}
// add an IP route, return -1 if error, 0 if the route was added
int net_add_route(uint32_t ip, uint32_t mask, uint32_t gw) {
int sock;
struct rtentry route;
struct sockaddr_in *addr;
int err = 0;
// create the socket
if((sock = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
errExit("socket");
memset(&route, 0, sizeof(route));
addr = (struct sockaddr_in*) &route.rt_gateway;
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = htonl(gw);
addr = (struct sockaddr_in*) &route.rt_dst;
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = htonl(ip);
addr = (struct sockaddr_in*) &route.rt_genmask;
addr->sin_family = AF_INET;
addr->sin_addr.s_addr = htonl(mask);
route.rt_flags = RTF_UP | RTF_GATEWAY;
route.rt_metric = 0;
if ((err = ioctl(sock, SIOCADDRT, &route)) != 0) {
close(sock);
return -1;
}
close(sock);
return 0;
}
#define BUFSIZE 1024
uint32_t network_get_defaultgw(void) {
FILE *fp = fopen("/proc/self/net/route", "r");
if (!fp)
errExit("fopen");
char buf[BUFSIZE];
uint32_t retval = 0;
while (fgets(buf, BUFSIZE, fp)) {
if (strncmp(buf, "Iface", 5) == 0)
continue;
char *ptr = buf;
while (*ptr != ' ' && *ptr != '\t')
ptr++;
while (*ptr == ' ' || *ptr == '\t')
ptr++;
unsigned dest;
unsigned gw;
int rv = sscanf(ptr, "%x %x", &dest, &gw);
if (rv == 2 && dest == 0) {
retval = ntohl(gw);
break;
}
}
fclose(fp);
return retval;
}
int net_config_mac(const char *ifname, const unsigned char mac[6]) {
char *macstr;
if (asprintf(&macstr, "%02x:%02x:%02x:%02x:%02x:%02x",
mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]) == -1)
errExit("asprintf");
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP, 5,
PATH_FNET, "config", "mac", ifname, macstr);
free(macstr);
return 0;
}
int net_get_mac(const char *ifname, unsigned char mac[6]) {
struct ifreq ifr;
int sock;
if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
errExit("socket");
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
ifr.ifr_hwaddr.sa_family = ARPHRD_ETHER;
if (ioctl(sock, SIOCGIFHWADDR, &ifr) == -1)
errExit("ioctl");
memcpy(mac, ifr.ifr_hwaddr.sa_data, 6);
close(sock);
return 0;
}
void net_config_interface(const char *dev, uint32_t ip, uint32_t mask, int mtu) {
assert(dev);
char *ipstr;
if (asprintf(&ipstr, "%llu", (long long unsigned) ip) == -1)
errExit("asprintf");
char *maskstr;
if (asprintf(&maskstr, "%llu", (long long unsigned) mask) == -1)
errExit("asprintf");
char *mtustr;
if (asprintf(&mtustr, "%d", mtu) == -1)
errExit("asprintf");
sbox_run(SBOX_ROOT | SBOX_CAPS_NETWORK | SBOX_SECCOMP, 7,
PATH_FNET, "config", "interface", dev, ipstr, maskstr, mtustr);
free(ipstr);
free(maskstr);
free(mtustr);
}
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