detect: ssh_proto stickybuffer

src/Makefile.am

@@ -213,6 +213,7 @@ detect-rpc.c detect-rpc.h \
 detect-sameip.c detect-sameip.h \
 detect-seq.c detect-seq.h \
 detect-sid.c detect-sid.h \
+detect-ssh-proto.c detect-ssh-proto.h \
 detect-ssh-proto-version.c detect-ssh-proto-version.h \
 detect-ssh-software-version.c detect-ssh-software-version.h \
 detect-ssl-state.c detect-ssl-state.h \

src/detect-ssh-proto.c

@@ -0,0 +1,216 @@
+/* Copyright (C) 2007-2016 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 sshlayer
+ *
+ * @{
+ */
+
+
+/**
+ * \file
+ *
+ * \author Victor Julien <victor@inliniac.net>
+ *
+ * Implements support ssh_proto sticky buffer
+ */
+
+#include "suricata-common.h"
+#include "threads.h"
+#include "decode.h"
+
+#include "detect.h"
+#include "detect-parse.h"
+#include "detect-engine.h"
+#include "detect-engine-mpm.h"
+#include "detect-engine-state.h"
+#include "detect-engine-prefilter.h"
+#include "detect-engine-content-inspection.h"
+
+#include "app-layer.h"
+#include "app-layer-parser.h"
+#include "app-layer-ssh.h"
+
+#define KEYWORD_NAME "ssh_proto"
+#define KEYWORD_DOC "ssh-keywords#ssh-protocol"
+#define BUFFER_NAME "ssh_protocol"
+#define BUFFER_DESC "ssh protocol field"
+static int g_buffer_id = 0;
+
+/** \brief SSH Protocol Mpm prefilter callback
+ *
+ *  \param det_ctx detection engine thread ctx
+ *  \param p packet to inspect
+ *  \param f flow to inspect
+ *  \param txv tx to inspect
+ *  \param pectx inspection context
+ */
+static void PrefilterTxSshRequestProtocol(DetectEngineThreadCtx *det_ctx,
+        const void *pectx,
+        Packet *p, Flow *f, void *txv,
+        const uint64_t idx, const uint8_t flags)
+{
+    SCEnter();
+
+    const MpmCtx *mpm_ctx = (MpmCtx *)pectx;
+    const SshState *ssh_state = txv;
+
+    if (ssh_state->cli_hdr.proto_version == NULL)
+        return;
+
+    uint32_t buffer_len = strlen((char *)ssh_state->cli_hdr.proto_version);
+    const uint8_t *buffer = ssh_state->cli_hdr.proto_version;
+
+    if (buffer_len >= mpm_ctx->minlen) {
+        (void)mpm_table[mpm_ctx->mpm_type].Search(mpm_ctx,
+                &det_ctx->mtcu, &det_ctx->pmq, buffer, buffer_len);
+    }
+}
+
+static int PrefilterTxSshRequestProtocolRegister(SigGroupHead *sgh, MpmCtx *mpm_ctx)
+{
+    SCEnter();
+
+    int r = PrefilterAppendTxEngine(sgh, PrefilterTxSshRequestProtocol,
+        ALPROTO_SSH, SSH_STATE_BANNER_DONE,
+        mpm_ctx, NULL, KEYWORD_NAME " (request)");
+    return r;
+}
+
+/** \brief SSH Protocol Mpm prefilter callback
+ *
+ *  \param det_ctx detection engine thread ctx
+ *  \param p packet to inspect
+ *  \param f flow to inspect
+ *  \param txv tx to inspect
+ *  \param pectx inspection context
+ */
+static void PrefilterTxSshResponseProtocol(DetectEngineThreadCtx *det_ctx,
+        const void *pectx,
+        Packet *p, Flow *f, void *txv,
+        const uint64_t idx, const uint8_t flags)
+{
+    SCEnter();
+
+    const MpmCtx *mpm_ctx = (MpmCtx *)pectx;
+    const SshState *ssh_state = txv;
+
+    if (ssh_state->srv_hdr.proto_version == NULL)
+        return;
+
+    uint32_t buffer_len = strlen((char *)ssh_state->srv_hdr.proto_version);
+    const uint8_t *buffer = ssh_state->srv_hdr.proto_version;
+
+    if (buffer_len >= mpm_ctx->minlen) {
+        (void)mpm_table[mpm_ctx->mpm_type].Search(mpm_ctx,
+                &det_ctx->mtcu, &det_ctx->pmq, buffer, buffer_len);
+    }
+}
+
+static int PrefilterTxSshResponseProtocolRegister(SigGroupHead *sgh, MpmCtx *mpm_ctx)
+{
+    SCEnter();
+
+    int r = PrefilterAppendTxEngine(sgh, PrefilterTxSshResponseProtocol,
+        ALPROTO_SSH, SSH_STATE_BANNER_DONE,
+        mpm_ctx, NULL, KEYWORD_NAME " (response)");
+    return r;
+}
+
+static int InspectEngineSshProtocol(ThreadVars *tv,
+        DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
+        const Signature *s, const SigMatchData *smd,
+        Flow *f, uint8_t flags, void *alstate, void *tx, uint64_t tx_id)
+{
+    uint8_t *protocol = NULL;
+    SshState *ssh_state = alstate;
+
+    if (flags & STREAM_TOSERVER)
+        protocol = ssh_state->cli_hdr.proto_version;
+    else if (flags & STREAM_TOCLIENT)
+        protocol = ssh_state->srv_hdr.proto_version;
+    if (protocol == NULL)
+        goto end;
+
+    uint32_t buffer_len = strlen((char *)protocol);
+    uint8_t *buffer = protocol;
+    if (buffer == NULL ||buffer_len == 0)
+        goto end;
+
+    det_ctx->buffer_offset = 0;
+    det_ctx->discontinue_matching = 0;
+    det_ctx->inspection_recursion_counter = 0;
+    int r = DetectEngineContentInspection(de_ctx, det_ctx, s, smd,
+                                          f,
+                                          buffer, buffer_len,
+                                          0,
+                                          DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE, NULL);
+    if (r == 1)
+        return DETECT_ENGINE_INSPECT_SIG_MATCH;
+
+ end:
+    if (flags & STREAM_TOSERVER) {
+        if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_SSH, tx, flags) >= SSH_STATE_BANNER_DONE)
+            return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH;
+    } else {
+        if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_SSH, tx, flags) >= SSH_STATE_BANNER_DONE)
+            return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH;
+    }
+    return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;
+}
+
+static int DetectSshProtocolSetup(DetectEngineCtx *de_ctx, Signature *s, char *arg)
+{
+    s->init_data->list = g_buffer_id;
+    return 0;
+}
+
+static void DetectSshProtocolSetupCallback(Signature *s)
+{
+    SCLogDebug("callback invoked by %u", s->id);
+    s->mask |= SIG_MASK_REQUIRE_SSH_STATE;
+}
+
+void DetectSshProtocolRegister(void)
+{
+    sigmatch_table[DETECT_AL_SSH_PROTOCOL].name = KEYWORD_NAME;
+    sigmatch_table[DETECT_AL_SSH_PROTOCOL].desc = BUFFER_NAME " sticky buffer";
+    sigmatch_table[DETECT_AL_SSH_PROTOCOL].url = DOC_URL DOC_VERSION "/rules/" KEYWORD_DOC;
+    sigmatch_table[DETECT_AL_SSH_PROTOCOL].Setup = DetectSshProtocolSetup;
+    sigmatch_table[DETECT_AL_SSH_PROTOCOL].flags |= SIGMATCH_NOOPT ;
+
+    DetectAppLayerMpmRegister(BUFFER_NAME, SIG_FLAG_TOSERVER, 2,
+            PrefilterTxSshRequestProtocolRegister);
+    DetectAppLayerMpmRegister(BUFFER_NAME, SIG_FLAG_TOCLIENT, 2,
+            PrefilterTxSshResponseProtocolRegister);
+
+    DetectAppLayerInspectEngineRegister(BUFFER_NAME,
+            ALPROTO_SSH, SIG_FLAG_TOSERVER,
+            InspectEngineSshProtocol);
+    DetectAppLayerInspectEngineRegister(BUFFER_NAME,
+            ALPROTO_SSH, SIG_FLAG_TOCLIENT,
+            InspectEngineSshProtocol);
+
+    DetectBufferTypeSetDescriptionByName(BUFFER_NAME,
+            BUFFER_DESC);
+
+    DetectBufferTypeRegisterSetupCallback(BUFFER_NAME,
+            DetectSshProtocolSetupCallback);
+
+    g_buffer_id = DetectBufferTypeGetByName(BUFFER_NAME);
+}

src/detect-ssh-proto.h

@@ -0,0 +1,29 @@
+/* Copyright (C) 2007-2016 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 Victor Julien <victor@inliniac.net>
+ */
+
+#ifndef __DETECT_SSH_PROTOCOL_H__
+#define __DETECT_SSH_PROTOCOL_H__
+
+void DetectSshProtocolRegister(void);
+
+#endif /* __DETECT_SSH_PROTOCOL_H__ */

src/detect.c

@@ -182,6 +182,7 @@
 #include "detect-tls.h"
 #include "detect-tls-cert-validity.h"
 #include "detect-tls-version.h"
+#include "detect-ssh-proto.h"
 #include "detect-ssh-proto-version.h"
 #include "detect-ssh-software-version.h"
 #include "detect-http-stat-code.h"
@@ -4092,6 +4093,7 @@ void SigTableSetup(void)
     DetectUrilenRegister();
     DetectDetectionFilterRegister();
     DetectAsn1Register();
+    DetectSshProtocolRegister();
     DetectSshVersionRegister();
     DetectSshSoftwareVersionRegister();
     DetectSslStateRegister();

src/detect.h

@@ -1249,6 +1249,7 @@ enum {
     DETECT_AL_HTTP_RAW_HOST,
     DETECT_AL_HTTP_REQUEST_LINE,
     DETECT_AL_HTTP_RESPONSE_LINE,
+    DETECT_AL_SSH_PROTOCOL,
     DETECT_AL_SSH_PROTOVERSION,
     DETECT_AL_SSH_SOFTWAREVERSION,
     DETECT_AL_SSL_VERSION,