1 files changed, 370 insertions, 0 deletions

diff --git a/src/fnet/interface.c b/src/fnet/interface.c
new file mode 100644
index 000000000..3958efddd
--- /dev/null
+++ b/src/fnet/interface.c
@@ -0,0 +1,370 @@
+ /*
+ * 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 "fnet.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>
+
+static void check_if_name(const char *ifname) {
+        if (strlen(ifname) > IFNAMSIZ) {
+                fprintf(stderr, "Error fnet: invalid network device name %s\n", ifname);
+                exit(1);
+        }
+}
+
+// add a veth device to a bridge
+void net_bridge_add_interface(const char *bridge, const char *dev) {
+        check_if_name(bridge);
+        check_if_name(dev);
+        
+        // somehow adding the interface to the bridge resets MTU on bridge device!!!
+        // workaround: restore MTU on the bridge device
+        // todo: put a real fix in
+        int mtu1 = net_get_mtu(bridge);
+
+        struct ifreq ifr;
+        int err;
+        int ifindex = if_nametoindex(dev);
+
+        if (ifindex <= 0)
+                errExit("if_nametoindex");
+
+        int sock;
+        if ((sock = socket(AF_INET, SOCK_STREAM, 0)) < 0)
+                errExit("socket");
+
+        memset(&ifr, 0, sizeof(ifr));
+        strncpy(ifr.ifr_name, bridge, IFNAMSIZ);
+#ifdef SIOCBRADDIF
+        ifr.ifr_ifindex = ifindex;
+        err = ioctl(sock, SIOCBRADDIF, &ifr);
+        if (err < 0)
+#endif
+        {
+                unsigned long args[4] = { BRCTL_ADD_IF, ifindex, 0, 0 };
+
+                ifr.ifr_data = (char *) args;
+                err = ioctl(sock, SIOCDEVPRIVATE, &ifr);
+        }
+        (void) err;
+        close(sock);
+
+        int mtu2 = net_get_mtu(bridge);
+        if (mtu1 != mtu2)
+                net_set_mtu(bridge, mtu1);
+}
+
+
+// bring interface up
+void net_if_up(const char *ifname) {
+        check_if_name(ifname);
+        
+        int sock = socket(AF_INET,SOCK_DGRAM,0);
+        if (sock < 0)
+                errExit("socket");
+
+        // get the existing interface flags
+        struct ifreq ifr;
+        memset(&ifr, 0, sizeof(ifr));
+        strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+        ifr.ifr_addr.sa_family = AF_INET;
+
+        // read the existing flags
+        if (ioctl(sock, SIOCGIFFLAGS, &ifr ) < 0)
+                errExit("ioctl");
+
+        ifr.ifr_flags |= IFF_UP;
+
+        // set the new flags
+        if (ioctl( sock, SIOCSIFFLAGS, &ifr ) < 0)
+                errExit("ioctl");
+
+        // checking
+        // read the existing flags
+        if (ioctl(sock, SIOCGIFFLAGS, &ifr ) < 0)
+                errExit("ioctl");
+
+        // wait not more than 500ms for the interface to come up
+        int cnt = 0;
+        while (cnt < 50) {
+                usleep(10000);                    // sleep 10ms
+
+                // read the existing flags
+                if (ioctl(sock, SIOCGIFFLAGS, &ifr ) < 0)
+                        errExit("ioctl");
+                if (ifr.ifr_flags & IFF_RUNNING)
+                        break;
+                cnt++;
+        }
+
+        close(sock);
+}
+
+int net_get_mtu(const char *ifname) {
+        check_if_name(ifname);
+        int mtu = 0;
+        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;
+        close(s);
+        
+        
+        return mtu;
+}
+
+void net_set_mtu(const char *ifname, int mtu) {
+        check_if_name(ifname);
+        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)
+                fprintf(stderr, "Warning fnet: cannot set mtu for interface %s\n", ifname);
+        close(s);
+}
+
+// scan interfaces in current namespace and print IP address/mask for each interface
+void net_ifprint(int scan) {
+        uint32_t ip;
+        uint32_t mask;
+        struct ifaddrs *ifaddr, *ifa;
+
+        if (getifaddrs(&ifaddr) == -1)
+                errExit("getifaddrs");
+
+        printf("%-17.17s%-19.19s%-17.17s%-17.17s%-6.6s\n",
+                "Interface", "MAC", "IP", "Mask", "Status");
+        // walk through the linked list
+        for (ifa = ifaddr; ifa != NULL; ifa = ifa->ifa_next) {
+                if (ifa->ifa_addr == NULL)
+                        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);
+
+                        // interface status
+                        char *status;
+                        if (ifa->ifa_flags & IFF_RUNNING && ifa->ifa_flags & IFF_UP)
+                                status = "UP";
+                        else
+                                status = "DOWN";
+
+                        // ip address and mask
+                        char ipstr[30];
+                        sprintf(ipstr, "%d.%d.%d.%d", PRINT_IP(ip));
+                        char maskstr[30];
+                        sprintf(maskstr, "%d.%d.%d.%d", PRINT_IP(mask));
+                        
+                        // mac address
+                        unsigned char mac[6];
+                        net_get_mac(ifa->ifa_name, mac);
+                        char macstr[30];
+                        if (strcmp(ifa->ifa_name, "lo") == 0)
+                                macstr[0] = '\0';
+                        else
+                                sprintf(macstr, "%02x:%02x:%02x:%02x:%02x:%02x", PRINT_MAC(mac));
+
+                        // print                                
+                        printf("%-17.17s%-19.19s%-17.17s%-17.17s%-6.6s\n",
+                                ifa->ifa_name, macstr, ipstr, maskstr, status);
+
+                        // network scanning
+                        if (!scan)                              // scanning disabled
+                                continue;
+                        if (strcmp(ifa->ifa_name, "lo") == 0)   // no loopbabck scanning
+                                continue;
+                        if (mask2bits(mask) < 16)               // not scanning large networks
+                                continue;
+                        if (!ip)                                        // if not configured
+                                continue;
+                        // only if the interface is up and running
+                        if (ifa->ifa_flags & IFF_RUNNING && ifa->ifa_flags & IFF_UP)
+                                arp_scan(ifa->ifa_name, ip, mask);
+                }
+        }
+        freeifaddrs(ifaddr);
+}
+
+int net_get_mac(const char *ifname, unsigned char mac[6]) {
+        check_if_name(ifname);
+
+        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;
+}
+
+// configure interface ipv4 address
+void net_if_ip(const char *ifname, uint32_t ip, uint32_t mask, int mtu) {
+        check_if_name(ifname);
+        int sock = socket(AF_INET,SOCK_DGRAM,0);
+        if (sock < 0)
+                errExit("socket");
+
+        struct ifreq ifr;
+        memset(&ifr, 0, sizeof(ifr));
+        strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+        ifr.ifr_addr.sa_family = AF_INET;
+
+        ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr = htonl(ip);
+        if (ioctl( sock, SIOCSIFADDR, &ifr ) < 0) 
+                errExit("ioctl");
+
+        if (ip != 0) {
+                ((struct sockaddr_in *)&ifr.ifr_addr)->sin_addr.s_addr =  htonl(mask);
+                if (ioctl( sock, SIOCSIFNETMASK, &ifr ) < 0)
+                        errExit("ioctl");
+        }
+        
+        // configure mtu
+        if (mtu > 0) {
+                ifr.ifr_mtu = mtu;
+                if (ioctl( sock, SIOCSIFMTU, &ifr ) < 0)
+                        errExit("ioctl");
+        }
+
+        close(sock);
+        usleep(10000);                            // sleep 10ms
+        return;
+}
+
+int net_if_mac(const char *ifname, const unsigned char mac[6]) {
+        check_if_name(ifname);
+        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;
+        memcpy(ifr.ifr_hwaddr.sa_data, mac, 6);
+        
+        if (ioctl(sock, SIOCSIFHWADDR, &ifr) == -1)
+                errExit("ioctl");
+        close(sock);
+        return 0;
+}
+
+// configure interface ipv6 address
+// ex: firejail --net=eth0 --ip6=2001:0db8:0:f101::1/64
+struct ifreq6 {
+        struct in6_addr ifr6_addr;
+        uint32_t ifr6_prefixlen;
+        unsigned int ifr6_ifindex;
+};
+void net_if_ip6(const char *ifname, const char *addr6) {
+        check_if_name(ifname);
+        if (strchr(addr6, ':') == NULL) {
+                fprintf(stderr, "Error fnet: invalid IPv6 address %s\n", addr6);
+                exit(1);
+        }
+        
+        // extract prefix
+        unsigned long prefix;
+        char *ptr;
+        if ((ptr = strchr(addr6, '/'))) {
+                prefix = atol(ptr + 1);
+                if (prefix > 128) {
+                        fprintf(stderr, "Error fnet: invalid prefix for IPv6 address %s\n", addr6);
+                        exit(1);
+                }
+                *ptr = '\0';    // mark the end of the address
+        }
+        else
+                prefix = 128;
+
+        // extract address
+        struct sockaddr_in6 sin6;
+        memset(&sin6, 0, sizeof(sin6));
+        sin6.sin6_family = AF_INET6;
+        int rv = inet_pton(AF_INET6, addr6, sin6.sin6_addr.s6_addr);
+        if (rv <= 0) {
+                fprintf(stderr, "Error fnet: invalid IPv6 address %s\n", addr6);
+                exit(1);
+        }
+
+        // open socket
+        int sock = socket(PF_INET6, SOCK_DGRAM, IPPROTO_IP);
+        if (sock < 0) {
+                fprintf(stderr, "Error fnet: IPv6 is not supported on this system\n");
+                exit(1);
+        }
+
+        // find interface index
+        struct ifreq ifr;
+        memset(&ifr, 0, sizeof(ifr));
+        strncpy(ifr.ifr_name, ifname, IFNAMSIZ);
+        ifr.ifr_addr.sa_family = AF_INET;
+        if (ioctl(sock, SIOGIFINDEX, &ifr) < 0) {
+                perror("ioctl SIOGIFINDEX");
+                exit(1);
+        }
+
+        // configure address
+        struct ifreq6 ifr6;
+        memset(&ifr6, 0, sizeof(ifr6));
+        ifr6.ifr6_prefixlen = prefix;
+        ifr6.ifr6_ifindex = ifr.ifr_ifindex;
+        memcpy((char *) &ifr6.ifr6_addr, (char *) &sin6.sin6_addr, sizeof(struct in6_addr));
+        if (ioctl(sock, SIOCSIFADDR, &ifr6) < 0) {
+                perror("ioctl SIOCSIFADDR");
+                exit(1);
+        }
+        
+        close(sock);
+}