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/* Copyright (C) 2007-2019 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 httplayer
*
* @{
*/
/**
* \file
*
* \author Brian Rectanus <brectanu@gmail.com>
*
* Implements the http_method 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-mpm.h"
#include "detect-engine-prefilter.h"
#include "detect-content.h"
#include "detect-pcre.h"
#include "flow.h"
#include "flow-var.h"
#include "flow-util.h"
#include "util-debug.h"
#include "util-unittest.h"
#include "util-unittest-helper.h"
#include "util-spm.h"
#include "app-layer.h"
#include "app-layer-parser.h"
#include "app-layer-htp.h"
#include "detect-http-method.h"
#include "stream-tcp.h"
static int g_http_method_buffer_id = 0;
static int DetectHttpMethodSetup(DetectEngineCtx *, Signature *, const char *);
static int DetectHttpMethodSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str);
#ifdef UNITTESTS
void DetectHttpMethodRegisterTests(void);
#endif
void DetectHttpMethodFree(void *);
static bool DetectHttpMethodValidateCallback(const Signature *s, const char **sigerror);
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Flow *_f,
const uint8_t _flow_flags, void *txv, const int list_id);
static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
const int list_id);
/**
* \brief Registration function for keyword: http_method
*/
void DetectHttpMethodRegister(void)
{
/* http_method content modifier */
sigmatch_table[DETECT_AL_HTTP_METHOD].name = "http_method";
sigmatch_table[DETECT_AL_HTTP_METHOD].desc = "content modifier to match only on the HTTP method-buffer";
sigmatch_table[DETECT_AL_HTTP_METHOD].url = "/rules/http-keywords.html#http-method";
sigmatch_table[DETECT_AL_HTTP_METHOD].Match = NULL;
sigmatch_table[DETECT_AL_HTTP_METHOD].Setup = DetectHttpMethodSetup;
#ifdef UNITTESTS
sigmatch_table[DETECT_AL_HTTP_METHOD].RegisterTests = DetectHttpMethodRegisterTests;
#endif
sigmatch_table[DETECT_AL_HTTP_METHOD].flags |= SIGMATCH_NOOPT|SIGMATCH_INFO_CONTENT_MODIFIER;
sigmatch_table[DETECT_AL_HTTP_METHOD].alternative = DETECT_HTTP_METHOD;
/* http.method sticky buffer */
sigmatch_table[DETECT_HTTP_METHOD].name = "http.method";
sigmatch_table[DETECT_HTTP_METHOD].desc = "sticky buffer to match specifically and only on the HTTP method buffer";
sigmatch_table[DETECT_HTTP_METHOD].url = "/rules/http-keywords.html#http-method";
sigmatch_table[DETECT_HTTP_METHOD].Setup = DetectHttpMethodSetupSticky;
sigmatch_table[DETECT_HTTP_METHOD].flags |= SIGMATCH_NOOPT|SIGMATCH_INFO_STICKY_BUFFER;
DetectAppLayerInspectEngineRegister2("http_method", ALPROTO_HTTP1, SIG_FLAG_TOSERVER,
HTP_REQUEST_LINE, DetectEngineInspectBufferGeneric, GetData);
DetectAppLayerMpmRegister2("http_method", SIG_FLAG_TOSERVER, 4, PrefilterGenericMpmRegister,
GetData, ALPROTO_HTTP1, HTP_REQUEST_LINE);
DetectAppLayerInspectEngineRegister2("http_method", ALPROTO_HTTP2, SIG_FLAG_TOSERVER,
HTTP2StateDataClient, DetectEngineInspectBufferGeneric, GetData2);
DetectAppLayerMpmRegister2("http_method", SIG_FLAG_TOSERVER, 4, PrefilterGenericMpmRegister,
GetData2, ALPROTO_HTTP2, HTTP2StateDataClient);
DetectBufferTypeSetDescriptionByName("http_method",
"http request method");
DetectBufferTypeRegisterValidateCallback("http_method",
DetectHttpMethodValidateCallback);
g_http_method_buffer_id = DetectBufferTypeGetByName("http_method");
SCLogDebug("registering http_method rule option");
}
/**
* \brief This function is used to add the parsed "http_method" option
* into the current signature.
*
* \param de_ctx Pointer to the Detection Engine Context.
* \param s Pointer to the Current Signature.
* \param str Pointer to the user provided option string.
*
* \retval 0 on Success.
* \retval -1 on Failure.
*/
static int DetectHttpMethodSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
return DetectEngineContentModifierBufferSetup(
de_ctx, s, str, DETECT_AL_HTTP_METHOD, g_http_method_buffer_id, ALPROTO_HTTP1);
}
/**
* \brief this function setup the http.method keyword used in the rule
*
* \param de_ctx Pointer to the Detection Engine Context
* \param s Pointer to the Signature to which the current keyword belongs
* \param str Should hold an empty string always
*
* \retval 0 On success
*/
static int DetectHttpMethodSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
if (DetectBufferSetActiveList(de_ctx, s, g_http_method_buffer_id) < 0)
return -1;
if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) < 0)
return -1;
return 0;
}
/**
* \retval 1 valid
* \retval 0 invalid
*/
static bool DetectHttpMethodValidateCallback(const Signature *s, const char **sigerror)
{
for (uint32_t x = 0; x < s->init_data->buffer_index; x++) {
if (s->init_data->buffers[x].id != (uint32_t)g_http_method_buffer_id)
continue;
const SigMatch *sm = s->init_data->buffers[x].head;
for (; sm != NULL; sm = sm->next) {
if (sm->type != DETECT_CONTENT)
continue;
const DetectContentData *cd = (const DetectContentData *)sm->ctx;
if (cd->content && cd->content_len) {
if (cd->content[cd->content_len - 1] == 0x20) {
*sigerror = "http_method pattern with trailing space";
SCLogError("%s", *sigerror);
return false;
} else if (cd->content[0] == 0x20) {
*sigerror = "http_method pattern with leading space";
SCLogError("%s", *sigerror);
return false;
} else if (cd->content[cd->content_len - 1] == 0x09) {
*sigerror = "http_method pattern with trailing tab";
SCLogError("%s", *sigerror);
return false;
} else if (cd->content[0] == 0x09) {
*sigerror = "http_method pattern with leading tab";
SCLogError("%s", *sigerror);
return false;
}
}
}
}
return true;
}
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Flow *_f,
const uint8_t _flow_flags, void *txv, const int list_id)
{
InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
if (buffer->inspect == NULL) {
htp_tx_t *tx = (htp_tx_t *)txv;
if (tx->request_method == NULL)
return NULL;
const uint32_t data_len = bstr_len(tx->request_method);
const uint8_t *data = bstr_ptr(tx->request_method);
InspectionBufferSetup(det_ctx, list_id, buffer, data, data_len);
InspectionBufferApplyTransforms(buffer, transforms);
}
return buffer;
}
static InspectionBuffer *GetData2(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms, Flow *_f, const uint8_t _flow_flags, void *txv,
const int list_id)
{
InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id);
if (buffer->inspect == NULL) {
uint32_t b_len = 0;
const uint8_t *b = NULL;
if (rs_http2_tx_get_method(txv, &b, &b_len) != 1)
return NULL;
if (b == NULL || b_len == 0)
return NULL;
InspectionBufferSetup(det_ctx, list_id, buffer, b, b_len);
InspectionBufferApplyTransforms(buffer, transforms);
}
return buffer;
}
#ifdef UNITTESTS
#include "tests/detect-http-method.c"
#endif
/**
* @}
*/
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