diff --git a/src/Makefile.am b/src/Makefile.am index 5f5e34534a..cdb6c22d67 100644 --- a/src/Makefile.am +++ b/src/Makefile.am @@ -34,6 +34,7 @@ decode-ethernet.c decode-ethernet.h \ decode-vlan.c decode-vlan.h \ decode-sll.c decode-sll.h \ decode-gre.c decode-gre.h \ +decode-teredo.c decode-teredo.h \ decode-ppp.c decode-ppp.h \ decode-pppoe.c decode-pppoe.h \ decode-ipv4.c decode-ipv4.h \ diff --git a/src/decode-teredo.c b/src/decode-teredo.c new file mode 100644 index 0000000000..9dea525172 --- /dev/null +++ b/src/decode-teredo.c @@ -0,0 +1,108 @@ +/* Copyright (C) 2012 Open Information Security Foundation + * + * You can copy, redistribute or modify this Program under the terms of + * the GNU General Public License version 2 as published by the Free + * Software Foundation. + * + * 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 + * version 2 along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +/** + * \ingroup decode + * + * @{ + */ + + +/** + * \file + * + * \author Eric Leblond + * + * Decode Teredo Tunneling protocol + */ + +#include "suricata-common.h" +#include "decode.h" +#include "decode-ipv6.h" +#include "util-debug.h" + +/** + * \brief Function to decode Teredo packets + * + * \retval 0 if packet is not a Teredo packet, 1 if it is + */ +int DecodeTeredo(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt, uint16_t len, PacketQueue *pq) +{ + + uint8_t *start = pkt; + + /* Is this packet to short to contain an IPv6 packet ? */ + if (len < IPV6_HEADER_LEN) + return 0; + + /* Teredo encapsulate IPv6 in UDP and can add some custom message + * part before the IPv6 packet. Here we iter on the messages to get + * on the IPv6 packet. */ + while (start[0] == 0x0) { + switch (start[1]) { + /* origin indication: compatible with tunnel */ + case 0x0: + if (len >= 8 + (pkt - start) + IPV6_HEADER_LEN) + start += 8; + else + return 0; + break; + /* authentication: negotiation not real tunnel */ + case 0x1: + return 0; + /* this case is not possible in Teredo: not that protocol */ + default: + return 0; + } + } + + /* There is no specific field that we can check to prove that the packet + * is a Teredo packet. We've zapped here all the possible Teredo header + * and we should have an IPv6 packet at the start pointer. + * We then can only do two checks before sending the encapsulated packets + * to decoding: + * - The packet has a protocol version which is IPv6. + * - The IPv6 length of the packet matches what remains in buffer. + */ + if (IP_GET_RAW_VER(start) == 6) { + IPV6Hdr *thdr = (IPV6Hdr *)start; + if (len == IPV6_HEADER_LEN + + IPV6_GET_RAW_PLEN(thdr) + (start - pkt)) { + if (pq != NULL) { + int blen = len - (start - pkt); + /* spawn off tunnel packet */ + Packet *tp = PacketPseudoPktSetup(p, start, blen, + IPPROTO_IPV6); + if (tp != NULL) { + /* send that to the Tunnel decoder */ + DecodeTunnel(tv, dtv, tp, start, blen, + pq, IPPROTO_IPV6); + /* add the tp to the packet queue. */ + PacketEnqueue(pq,tp); + return 1; + } + } + } + return 0; + } + + return 0; +} + +/** + * @} + */ diff --git a/src/decode-teredo.h b/src/decode-teredo.h new file mode 100644 index 0000000000..142d13c207 --- /dev/null +++ b/src/decode-teredo.h @@ -0,0 +1,19 @@ +/* Copyright (C) 2012 Open Information Security Foundation + * + * You can copy, redistribute or modify this Program under the terms of + * the GNU General Public License version 2 as published by the Free + * Software Foundation. + * + * 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 + * version 2 along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +int DecodeTeredo(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, + uint8_t *pkt, uint16_t len, PacketQueue *pq); diff --git a/src/decode-udp.c b/src/decode-udp.c index f9483d8126..c8fc0a7892 100644 --- a/src/decode-udp.c +++ b/src/decode-udp.c @@ -33,6 +33,7 @@ #include "suricata-common.h" #include "decode.h" #include "decode-udp.h" +#include "decode-teredo.h" #include "decode-events.h" #include "util-unittest.h" #include "util-debug.h" @@ -81,6 +82,13 @@ void DecodeUDP(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, uint8_t *pkt, u SCLogDebug("UDP sp: %" PRIu32 " -> dp: %" PRIu32 " - HLEN: %" PRIu32 " LEN: %" PRIu32 "", UDP_GET_SRC_PORT(p), UDP_GET_DST_PORT(p), UDP_HEADER_LEN, p->payload_len); + if (DecodeTeredo(tv, dtv, p, p->payload, p->payload_len, pq) == 1) { + /* Here we have a Teredo packet and don't need to handle app + * layer */ + FlowHandlePacket(tv, p); + return; + } + /* Flow is an integral part of us */ FlowHandlePacket(tv, p);