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131 lines
4.0 KiB
C
131 lines
4.0 KiB
C
/* Copyright (C) 2007-2016 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* \file
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*
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* \author Mats Klepsland <mats.klepsland@gmail.com>
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*
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* Implements support for tls.sni keyword.
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*/
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#include "suricata-common.h"
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#include "threads.h"
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#include "decode.h"
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#include "detect.h"
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#include "detect-parse.h"
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#include "detect-engine.h"
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#include "detect-engine-mpm.h"
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#include "detect-content.h"
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#include "detect-pcre.h"
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#include "flow.h"
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#include "flow-util.h"
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#include "flow-var.h"
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#include "util-debug.h"
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#include "util-spm.h"
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#include "util-print.h"
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#include "stream-tcp.h"
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#include "app-layer.h"
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#include "app-layer-ssl.h"
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#include "detect-engine-prefilter.h"
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#include "detect-tls-sni.h"
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#include "util-unittest.h"
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#include "util-unittest-helper.h"
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static int DetectTlsSniSetup(DetectEngineCtx *, Signature *, const char *);
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static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
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const DetectEngineTransforms *transforms,
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Flow *f, const uint8_t flow_flags,
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void *txv, const int list_id);
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static int g_tls_sni_buffer_id = 0;
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/**
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* \brief Registration function for keyword: tls.sni
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*/
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void DetectTlsSniRegister(void)
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{
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sigmatch_table[DETECT_AL_TLS_SNI].name = "tls.sni";
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sigmatch_table[DETECT_AL_TLS_SNI].alias = "tls_sni";
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sigmatch_table[DETECT_AL_TLS_SNI].desc =
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"sticky buffer to match specifically and only on the TLS SNI buffer";
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sigmatch_table[DETECT_AL_TLS_SNI].url = "/rules/tls-keywords.html#tls-sni";
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sigmatch_table[DETECT_AL_TLS_SNI].Setup = DetectTlsSniSetup;
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sigmatch_table[DETECT_AL_TLS_SNI].flags |= SIGMATCH_NOOPT;
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sigmatch_table[DETECT_AL_TLS_SNI].flags |= SIGMATCH_INFO_STICKY_BUFFER;
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DetectAppLayerInspectEngineRegister2("tls.sni", ALPROTO_TLS, SIG_FLAG_TOSERVER, 0,
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DetectEngineInspectBufferGeneric, GetData);
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DetectAppLayerMpmRegister2("tls.sni", SIG_FLAG_TOSERVER, 2,
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PrefilterGenericMpmRegister, GetData, ALPROTO_TLS, 0);
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DetectBufferTypeSetDescriptionByName("tls.sni",
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"TLS Server Name Indication (SNI) extension");
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g_tls_sni_buffer_id = DetectBufferTypeGetByName("tls.sni");
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}
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/**
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* \brief this function setup the tls.sni modifier keyword used in the rule
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*
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* \param de_ctx Pointer to the Detection Engine Context
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* \param s Pointer to the Signature to which the current keyword belongs
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* \param str Should hold an empty string always
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*
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* \retval 0 On success
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* \retval -1 On failure
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*/
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static int DetectTlsSniSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
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{
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if (DetectBufferSetActiveList(de_ctx, s, g_tls_sni_buffer_id) < 0)
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return -1;
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if (DetectSignatureSetAppProto(s, ALPROTO_TLS) < 0)
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return -1;
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return 0;
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}
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static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
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const DetectEngineTransforms *transforms, Flow *f,
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const uint8_t flow_flags, void *txv, const int list_id)
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{
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InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
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if (buffer->inspect == NULL) {
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const SSLState *ssl_state = (SSLState *)f->alstate;
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if (ssl_state->client_connp.sni == NULL) {
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return NULL;
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}
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const uint32_t data_len = strlen(ssl_state->client_connp.sni);
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const uint8_t *data = (uint8_t *)ssl_state->client_connp.sni;
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InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
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InspectionBufferApplyTransforms(buffer, transforms);
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}
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return buffer;
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}
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