--- /dev/null
+/* 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);
+}
projects / thirdparty / suricata.git / commitdiff
