nsh: Parsing of Network Services Header and payload

Support for EtherType 0x894F and basic header

diff --git a/src/Makefile.am b/src/Makefile.am
index 670848c70b4b4c2659fe905e4d8574e5e388fa29..825ce65d0dc0778ded39cf3d691071c36995dd0c 100755 (executable)
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -75,6 +75,7 @@ decode-icmpv4.c decode-icmpv4.h \
 decode-icmpv6.c decode-icmpv6.h \
 decode-ipv4.c decode-ipv4.h \
 decode-ipv6.c decode-ipv6.h \
+decode-nsh.c decode-nsh.h \
 decode-null.c decode-null.h \
 decode-ppp.c decode-ppp.h \
 decode-pppoe.c decode-pppoe.h \

diff --git a/src/decode-ethernet.h b/src/decode-ethernet.h
index 93ed61af89375f8cbc827b586919a03c96a5c5b0..7bbfa62df8d3784135f43813c196e106ff5ce452 100644 (file)
--- a/src/decode-ethernet.h
+++ b/src/decode-ethernet.h
@@ -48,6 +48,7 @@
 #define ETHERNET_TYPE_ERSPAN          0x88BE
 #define ETHERNET_TYPE_DCE             0x8903 /* Data center ethernet,
                                               * Cisco Fabric Path */
+#define ETHERNET_TYPE_NSH 0x894F
 
 typedef struct EthernetHdr_ {
     uint8_t eth_dst[6];

diff --git a/src/decode-events.c b/src/decode-events.c
index 3f18aabf9a24a8259399516df03d9f5f8d576587..2f2373cd0b2d365b1151f55f78cd2120bd0a78b4 100644 (file)
--- a/src/decode-events.c
+++ b/src/decode-events.c
@@ -535,6 +535,32 @@ const struct DecodeEvents_ DEvents[] = {
             CHDLC_PKT_TOO_SMALL,
     },
 
+    /* NSH events */
+    {
+            "decoder.nsh.header_too_small",
+            NSH_HEADER_TOO_SMALL,
+    },
+    {
+            "decoder.nsh.unsupported_version",
+            NSH_UNSUPPORTED_VERSION,
+    },
+    {
+            "decoder.nsh.bad_header_length",
+            NSH_BAD_HEADER_LENGTH,
+    },
+    {
+            "decoder.nsh.reserved_type",
+            NSH_RESERVED_TYPE,
+    },
+    {
+            "decoder.nsh.unsupported_type",
+            NSH_UNSUPPORTED_TYPE,
+    },
+    {
+            "decoder.nsh.unknown_payload",
+            NSH_UNKNOWN_PAYLOAD,
+    },
+
     /* STREAM EVENTS */
     {
             "stream.3whs_ack_in_wrong_dir",

diff --git a/src/decode-events.h b/src/decode-events.h
index 434dae1391da5643cb2e432c0015fe59e6741bf9..2c8467f1cd429f0ecf1ec4d18cc4ae0f44bbbb18 100644 (file)
--- a/src/decode-events.h
+++ b/src/decode-events.h
@@ -200,8 +200,16 @@ enum {
     /* Cisco HDLC events. */
     CHDLC_PKT_TOO_SMALL,
 
+    /* NSH events */
+    NSH_HEADER_TOO_SMALL,
+    NSH_UNSUPPORTED_VERSION,
+    NSH_BAD_HEADER_LENGTH,
+    NSH_RESERVED_TYPE,
+    NSH_UNSUPPORTED_TYPE,
+    NSH_UNKNOWN_PAYLOAD,
+
     /* END OF DECODE EVENTS ON SINGLE PACKET */
-    DECODE_EVENT_PACKET_MAX = CHDLC_PKT_TOO_SMALL,
+    DECODE_EVENT_PACKET_MAX = NSH_UNKNOWN_PAYLOAD,
 
     /* STREAM EVENTS */
     STREAM_3WHS_ACK_IN_WRONG_DIR,

diff --git a/src/decode-nsh.c b/src/decode-nsh.c
new file mode 100644 (file)
index 0000000..7a3355d
--- /dev/null
+++ b/src/decode-nsh.c
@@ -0,0 +1,289 @@
+/* Copyright (C) 2020 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 Carl Smith <carl.smith@alliedtelesis.co.nz>
+ *
+ * Decodes Network Service Header (NSH)
+ */
+
+#include "suricata-common.h"
+#include "suricata.h"
+#include "decode.h"
+#include "decode-events.h"
+#include "decode-nsh.h"
+
+#include "util-unittest.h"
+#include "util-debug.h"
+
+/**
+ * \brief Function to decode NSH packets
+ */
+
+int DecodeNSH(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p, const uint8_t *pkt, uint32_t len)
+{
+    StatsIncr(tv, dtv->counter_nsh);
+
+    /* Check mimimum header size */
+    if (len < sizeof(NshHdr)) {
+        ENGINE_SET_INVALID_EVENT(p, NSH_HEADER_TOO_SMALL);
+        return TM_ECODE_FAILED;
+    }
+
+    /* Sanity check the header version */
+    const NshHdr *hdr = (const NshHdr *)pkt;
+    uint16_t version = SCNtohs(hdr->ver_flags_len) >> 14;
+    if (version != 0) {
+        ENGINE_SET_EVENT(p, NSH_UNSUPPORTED_VERSION);
+        return TM_ECODE_OK;
+    }
+
+    /* Should always be some data after the header */
+    uint16_t length = (SCNtohs(hdr->ver_flags_len) & 0x003f) * 4;
+    if (length >= len) {
+        ENGINE_SET_INVALID_EVENT(p, NSH_BAD_HEADER_LENGTH);
+        return TM_ECODE_FAILED;
+    }
+
+    /* Check for valid MD types */
+    uint8_t md_type = hdr->md_type;
+    if (md_type == 0 || md_type == 0xF) {
+        /* We should silently ignore these packets */
+        ENGINE_SET_EVENT(p, NSH_RESERVED_TYPE);
+        return TM_ECODE_OK;
+    } else if (md_type == 1) {
+        /* Fixed header length format */
+        if (length != 24) {
+            ENGINE_SET_INVALID_EVENT(p, NSH_BAD_HEADER_LENGTH);
+            return TM_ECODE_FAILED;
+        }
+    } else if (md_type != 2) {
+        /* Not variable header length either */
+        ENGINE_SET_EVENT(p, NSH_UNSUPPORTED_TYPE);
+        return TM_ECODE_OK;
+    }
+
+    /* Now we can safely read the rest of the header */
+    uint8_t next_protocol = hdr->next_protocol;
+#ifdef DEBUG
+    if (SCLogDebugEnabled()) {
+        uint32_t spi_si = SCNtohl(hdr->spi_si);
+        uint32_t spi = ((spi_si & 0xFFFFFF00) >> 8);
+        uint8_t si = (uint8_t)(spi_si & 0xFF);
+        SCLogDebug("NSH: version %u length %u spi %u si %u next_protocol %u", version, length, spi,
+                si, next_protocol);
+    }
+#endif /* DEBUG */
+
+    /* Try to decode the payload */
+    switch (next_protocol) {
+        case NSH_NEXT_PROTO_IPV4:
+            return DecodeIPV4(tv, dtv, p, pkt + length, len - length);
+        case NSH_NEXT_PROTO_IPV6:
+            return DecodeIPV6(tv, dtv, p, pkt + length, len - length);
+        case NSH_NEXT_PROTO_ETHERNET:
+            return DecodeEthernet(tv, dtv, p, pkt + length, len - length);
+        case NSH_NEXT_PROTO_MPLS:
+            return DecodeMPLS(tv, dtv, p, pkt + length, len - length);
+        case NSH_NEXT_PROTO_NSH:
+        default:
+            SCLogDebug("NSH next protocol %u not supported", next_protocol);
+            ENGINE_SET_EVENT(p, NSH_UNKNOWN_PAYLOAD);
+            break;
+    }
+    return TM_ECODE_OK;
+}
+
+#ifdef UNITTESTS
+
+static uint8_t valid_nsh_packet[] = { 0x00, 0x04, 0x02, 0x01, 0x00, 0x00, 0x02, 0x02, 0x45, 0x10,
+    0x00, 0x3c, 0x78, 0x8f, 0x40, 0x00, 0x3f, 0x06, 0x79, 0x05, 0x0b, 0x06, 0x06, 0x06, 0x33, 0x06,
+    0x06, 0x06, 0xbd, 0x2e, 0x00, 0x16, 0xc9, 0xee, 0x07, 0x62, 0x00, 0x00, 0x00, 0x00, 0xa0, 0x02,
+    0x16, 0xd0, 0x2f, 0x36, 0x00, 0x00, 0x02, 0x04, 0x05, 0xb4, 0x04, 0x02, 0x08, 0x0a, 0xa9, 0x5f,
+    0x7f, 0xed, 0x00, 0x00, 0x00, 0x00, 0x01, 0x03, 0x03, 0x07 };
+
+static int DecodeNSHTestHeaderTooSmall(void)
+{
+    ThreadVars tv;
+    DecodeThreadVars dtv;
+    Packet *p;
+
+    p = SCMalloc(SIZE_OF_PACKET);
+    FAIL_IF_NULL(p);
+    memset(&dtv, 0, sizeof(DecodeThreadVars));
+    memset(&tv, 0, sizeof(ThreadVars));
+    memset(p, 0, SIZE_OF_PACKET);
+
+    /* A packet that is too small to have a complete NSH header */
+    DecodeNSH(&tv, &dtv, p, valid_nsh_packet, 7);
+    FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, NSH_HEADER_TOO_SMALL));
+
+    SCFree(p);
+    PASS;
+}
+
+static int DecodeNSHTestUnsupportedVersion(void)
+{
+    ThreadVars tv;
+    DecodeThreadVars dtv;
+    Packet *p;
+
+    p = SCMalloc(SIZE_OF_PACKET);
+    FAIL_IF_NULL(p);
+    memset(&dtv, 0, sizeof(DecodeThreadVars));
+    memset(&tv, 0, sizeof(ThreadVars));
+    memset(p, 0, SIZE_OF_PACKET);
+
+    /* Non-zero version field */
+    valid_nsh_packet[0] = 0xFF;
+    DecodeNSH(&tv, &dtv, p, valid_nsh_packet, sizeof(valid_nsh_packet));
+    valid_nsh_packet[0] = 0x00;
+    FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, NSH_UNSUPPORTED_VERSION));
+
+    SCFree(p);
+    PASS;
+}
+
+static int DecodeNSHTestPacketTooSmall(void)
+{
+    ThreadVars tv;
+    DecodeThreadVars dtv;
+    Packet *p;
+
+    p = SCMalloc(SIZE_OF_PACKET);
+    FAIL_IF_NULL(p);
+    memset(&dtv, 0, sizeof(DecodeThreadVars));
+    memset(&tv, 0, sizeof(ThreadVars));
+    memset(p, 0, SIZE_OF_PACKET);
+
+    /* A packet that has no payload */
+    DecodeNSH(&tv, &dtv, p, valid_nsh_packet, 8);
+    FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, NSH_BAD_HEADER_LENGTH));
+
+    SCFree(p);
+    PASS;
+}
+
+static int DecodeNSHTestReservedType(void)
+{
+    ThreadVars tv;
+    DecodeThreadVars dtv;
+    Packet *p;
+
+    p = SCMalloc(SIZE_OF_PACKET);
+    FAIL_IF_NULL(p);
+    memset(&dtv, 0, sizeof(DecodeThreadVars));
+    memset(&tv, 0, sizeof(ThreadVars));
+    memset(p, 0, SIZE_OF_PACKET);
+
+    /* Reserved type */
+    valid_nsh_packet[2] = 0x00;
+    DecodeNSH(&tv, &dtv, p, valid_nsh_packet, sizeof(valid_nsh_packet));
+    valid_nsh_packet[2] = 0x02;
+    FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, NSH_RESERVED_TYPE));
+
+    SCFree(p);
+    PASS;
+}
+
+static int DecodeNSHTestInvalidType(void)
+{
+    ThreadVars tv;
+    DecodeThreadVars dtv;
+    Packet *p;
+
+    p = SCMalloc(SIZE_OF_PACKET);
+    FAIL_IF_NULL(p);
+    memset(&dtv, 0, sizeof(DecodeThreadVars));
+    memset(&tv, 0, sizeof(ThreadVars));
+    memset(p, 0, SIZE_OF_PACKET);
+
+    /* Type length mismatch */
+    valid_nsh_packet[2] = 0x01;
+    DecodeNSH(&tv, &dtv, p, valid_nsh_packet, sizeof(valid_nsh_packet));
+    valid_nsh_packet[2] = 0x02;
+    FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, NSH_BAD_HEADER_LENGTH));
+    SCFree(p);
+    PASS;
+}
+
+static int DecodeNSHTestUnsupportedType(void)
+{
+    ThreadVars tv;
+    DecodeThreadVars dtv;
+    Packet *p;
+
+    p = SCMalloc(SIZE_OF_PACKET);
+    FAIL_IF_NULL(p);
+    memset(&dtv, 0, sizeof(DecodeThreadVars));
+    memset(&tv, 0, sizeof(ThreadVars));
+    memset(p, 0, SIZE_OF_PACKET);
+
+    /* Unsupported type */
+    valid_nsh_packet[2] = 0x03;
+    DecodeNSH(&tv, &dtv, p, valid_nsh_packet, sizeof(valid_nsh_packet));
+    valid_nsh_packet[2] = 0x02;
+    FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, NSH_UNSUPPORTED_TYPE));
+
+    SCFree(p);
+    PASS;
+}
+
+static int DecodeNSHTestUnknownPayload(void)
+{
+    ThreadVars tv;
+    DecodeThreadVars dtv;
+    Packet *p;
+
+    p = SCMalloc(SIZE_OF_PACKET);
+    FAIL_IF_NULL(p);
+    memset(&dtv, 0, sizeof(DecodeThreadVars));
+    memset(&tv, 0, sizeof(ThreadVars));
+    memset(p, 0, SIZE_OF_PACKET);
+
+    /* Unknown type */
+    valid_nsh_packet[3] = 0x99;
+    DecodeNSH(&tv, &dtv, p, valid_nsh_packet, sizeof(valid_nsh_packet));
+    valid_nsh_packet[3] = 0x01;
+    FAIL_IF_NOT(ENGINE_ISSET_EVENT(p, NSH_UNKNOWN_PAYLOAD));
+
+    SCFree(p);
+    PASS;
+}
+
+#endif /* UNITTESTS */
+
+void DecodeNSHRegisterTests(void)
+{
+#ifdef UNITTESTS
+    UtRegisterTest("DecodeNSHTestHeaderTooSmall", DecodeNSHTestHeaderTooSmall);
+    UtRegisterTest("DecodeNSHTestUnsupportedVersion", DecodeNSHTestUnsupportedVersion);
+    UtRegisterTest("DecodeNSHTestPacketTooSmall", DecodeNSHTestPacketTooSmall);
+    UtRegisterTest("DecodeNSHTestReservedType", DecodeNSHTestReservedType);
+    UtRegisterTest("DecodeNSHTestInvalidType", DecodeNSHTestInvalidType);
+    UtRegisterTest("DecodeNSHTestUnsupportedType", DecodeNSHTestUnsupportedType);
+    UtRegisterTest("DecodeNSHTestUnknownPayload", DecodeNSHTestUnknownPayload);
+#endif /* UNITTESTS */
+}

diff --git a/src/decode-nsh.h b/src/decode-nsh.h
new file mode 100644 (file)
index 0000000..e9c6af0
--- /dev/null
+++ b/src/decode-nsh.h
@@ -0,0 +1,52 @@
+/* Copyright (C) 2020 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.
+ */
+
+/**
+ * \file
+ *
+ * \author Carl Smith <carl.smith@alliedtelesis.co.nz>
+ *
+ */
+
+#ifndef __DECODE_NSH_H__
+#define __DECODE_NSH_H__
+
+#include "decode.h"
+#include "threadvars.h"
+
+#define NSH_NEXT_PROTO_UNASSIGNED  0x0
+#define NSH_NEXT_PROTO_IPV4        0x1
+#define NSH_NEXT_PROTO_IPV6        0x2
+#define NSH_NEXT_PROTO_ETHERNET    0x3
+#define NSH_NEXT_PROTO_NSH         0x4
+#define NSH_NEXT_PROTO_MPLS        0x5
+#define NSH_NEXT_PROTO_EXPERIMENT1 0xFE
+#define NSH_NEXT_PROTO_EXPERIMENT2 0xFF
+
+/*
+ * Network Service Header (NSH)
+ */
+typedef struct NshHdr_ {
+    uint16_t ver_flags_len;
+    uint8_t md_type;
+    uint8_t next_protocol;
+    uint32_t spi_si;
+} __attribute__((packed)) NshHdr;
+
+void DecodeNSHRegisterTests(void);
+
+#endif /* __DECODE_NSH_H__ */

diff --git a/src/decode.c b/src/decode.c
index 0c0ca72f1d493b08a49d476c102e0261544be2f7..93aec6338cbe76f3a41a696cb117dbc9da6b570f 100644 (file)
--- a/src/decode.c
+++ b/src/decode.c
@@ -92,6 +92,8 @@ int DecodeTunnel(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p,
             return DecodeERSPAN(tv, dtv, p, pkt, len);
         case DECODE_TUNNEL_ERSPANI:
             return DecodeERSPANTypeI(tv, dtv, p, pkt, len);
+        case DECODE_TUNNEL_NSH:
+            return DecodeNSH(tv, dtv, p, pkt, len);
         default:
             SCLogDebug("FIXME: DecodeTunnel: protocol %" PRIu32 " not supported.", proto);
             break;
@@ -517,6 +519,7 @@ void DecodeRegisterPerfCounters(DecodeThreadVars *dtv, ThreadVars *tv)
     dtv->counter_max_mac_addrs_src = StatsRegisterMaxCounter("decoder.max_mac_addrs_src", tv);
     dtv->counter_max_mac_addrs_dst = StatsRegisterMaxCounter("decoder.max_mac_addrs_dst", tv);
     dtv->counter_erspan = StatsRegisterMaxCounter("decoder.erspan", tv);
+    dtv->counter_nsh = StatsRegisterMaxCounter("decoder.nsh", tv);
     dtv->counter_flow_memcap = StatsRegisterCounter("flow.memcap", tv);
 
     dtv->counter_flow_tcp = StatsRegisterCounter("flow.tcp", tv);

diff --git a/src/decode.h b/src/decode.h
index fc298d94bd66b7cce0ff555d92386795dcbd86a9..7a583cf29b4917280e3faa24d840daac0dc1c043 100644 (file)
--- a/src/decode.h
+++ b/src/decode.h
@@ -95,6 +95,7 @@ enum PktSrcEnum {
 #include "decode-vlan.h"
 #include "decode-vxlan.h"
 #include "decode-mpls.h"
+#include "decode-nsh.h"
 
 #include "detect-reference.h"
 
@@ -668,6 +669,7 @@ typedef struct DecodeThreadVars_
     uint16_t counter_ipv4inipv6;
     uint16_t counter_ipv6inipv6;
     uint16_t counter_erspan;
+    uint16_t counter_nsh;
 
     /** frag stats - defrag runs in the context of the decoder. */
     uint16_t counter_defrag_ipv4_fragments;
@@ -908,6 +910,7 @@ enum DecodeTunnelProto {
     DECODE_TUNNEL_IPV6,
     DECODE_TUNNEL_IPV6_TEREDO, /**< separate protocol for stricter error handling */
     DECODE_TUNNEL_PPP,
+    DECODE_TUNNEL_NSH,
     DECODE_TUNNEL_UNSET
 };
 
@@ -962,6 +965,7 @@ int DecodeERSPAN(ThreadVars *, DecodeThreadVars *, Packet *, const uint8_t *, ui
 int DecodeERSPANTypeI(ThreadVars *, DecodeThreadVars *, Packet *, const uint8_t *, uint32_t);
 int DecodeCHDLC(ThreadVars *, DecodeThreadVars *, Packet *, const uint8_t *, uint32_t);
 int DecodeTEMPLATE(ThreadVars *, DecodeThreadVars *, Packet *, const uint8_t *, uint32_t);
+int DecodeNSH(ThreadVars *, DecodeThreadVars *, Packet *, const uint8_t *, uint32_t);
 
 #ifdef UNITTESTS
 void DecodeIPV6FragHeader(Packet *p, const uint8_t *pkt,
@@ -1259,6 +1263,9 @@ static inline bool DecodeNetworkLayer(ThreadVars *tv, DecodeThreadVars *dtv,
                 DecodeEthernet(tv, dtv, p, data, len);
             }
             break;
+        case ETHERNET_TYPE_NSH:
+            DecodeNSH(tv, dtv, p, data, len);
+            break;
         default:
             SCLogDebug("unknown ether type: %" PRIx16 "", proto);
             return false;

diff --git a/src/runmode-unittests.c b/src/runmode-unittests.c
index 7f458808cfaa5ddfc7be013d6d074a145209c613..0a631a59b537306f9874322ae40717ea381b1221 100644 (file)
--- a/src/runmode-unittests.c
+++ b/src/runmode-unittests.c
@@ -159,6 +159,7 @@ static void RegisterUnittests(void)
     DecodeUDPV4RegisterTests();
     DecodeGRERegisterTests();
     DecodeMPLSRegisterTests();
+    DecodeNSHRegisterTests();
     AppLayerProtoDetectUnittestsRegister();
     ConfRegisterTests();
     ConfYamlRegisterTests();