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suricata/src/detect-tls-alpn.c

126 lines
3.6 KiB
C

/* Copyright (C) 2024 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 <vjulien@oisf.net>
*
* Implements support for tls.alpn keyword.
*/
#include "suricata-common.h"
#include "threads.h"
#include "decode.h"
#include "detect.h"
#include "detect-parse.h"
#include "detect-engine.h"
#include "detect-engine-buffer.h"
#include "detect-engine-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-engine-content-inspection.h"
#include "detect-content.h"
#include "detect-tls-alpn.h"
#include "detect-engine-uint.h"
#include "flow.h"
#include "flow-util.h"
#include "flow-var.h"
#include "util-debug.h"
#include "util-spm.h"
#include "util-print.h"
#include "stream-tcp.h"
#include "app-layer.h"
#include "app-layer-ssl.h"
#include "util-profiling.h"
static int DetectTlsAlpnSetup(DetectEngineCtx *, Signature *, const char *);
static int g_tls_alpn_buffer_id = 0;
static bool TlsAlpnGetData(DetectEngineThreadCtx *det_ctx, const void *txv, const uint8_t flags,
uint32_t idx, const uint8_t **buf, uint32_t *buf_len)
{
SCEnter();
const SSLState *ssl_state = (SSLState *)txv;
const SSLStateConnp *connp;
CStringData d;
if (flags & STREAM_TOSERVER) {
connp = &ssl_state->client_connp;
} else {
connp = &ssl_state->server_connp;
}
if (SCTLSHandshakeGetALPN(connp->hs, idx, &d)) {
*buf = d.data;
*buf_len = (uint32_t)d.len;
return true;
} else {
return false;
}
}
/**
* \brief Registration function for keyword: tls.alpn
*/
void DetectTlsAlpnRegister(void)
{
sigmatch_table[DETECT_TLS_ALPN].name = "tls.alpn";
sigmatch_table[DETECT_TLS_ALPN].desc = "sticky buffer to match the TLS ALPN buffer";
sigmatch_table[DETECT_TLS_ALPN].url = "/rules/tls-keywords.html#tls-alpn";
sigmatch_table[DETECT_TLS_ALPN].Setup = DetectTlsAlpnSetup;
sigmatch_table[DETECT_TLS_ALPN].flags |= SIGMATCH_NOOPT;
sigmatch_table[DETECT_TLS_ALPN].flags |= SIGMATCH_INFO_STICKY_BUFFER;
DetectAppLayerMultiRegister("tls.alpn", ALPROTO_TLS, SIG_FLAG_TOSERVER,
TLS_STATE_CLIENT_HELLO_DONE, TlsAlpnGetData, 2);
DetectAppLayerMultiRegister(
"tls.alpn", ALPROTO_TLS, SIG_FLAG_TOCLIENT, TLS_STATE_SERVER_HELLO, TlsAlpnGetData, 2);
DetectBufferTypeSetDescriptionByName("tls.alpn", "TLS APLN");
DetectBufferTypeSupportsMultiInstance("tls.alpn");
g_tls_alpn_buffer_id = DetectBufferTypeGetByName("tls.alpn");
}
/**
* \brief This function setup the tls.alpn sticky buffer keyword
*
* \param de_ctx Pointer to the Detect Engine Context
* \param s Pointer to the Signature to which the keyword belongs
* \param str Should hold an empty string always
*
* \retval 0 On success
* \retval -1 On failure
*/
static int DetectTlsAlpnSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
if (SCDetectBufferSetActiveList(de_ctx, s, g_tls_alpn_buffer_id) < 0)
return -1;
if (DetectSignatureSetAppProto(s, ALPROTO_TLS) < 0)
return -1;
return 0;
}