aiden
/
suricata
mirror of https://github.com/OISF/suricata
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

detect: add http.user_agent sticky buffer

Browse Source
pull/3632/head
Victor Julien 7 years ago
parent fe738014e4
commit 123ebb2c41
3 changed files with 66 additions and 97 deletions
Show Stats Download Patch File Download Diff File

91
src/detect-engine-hua.c
Unescape Escape View File

@ -61,97 +61,6 @@
#include "detect-engine-hua.h"
#include "util-validate.h"
/** \brief HTTP UA 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 PrefilterTxUA(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;
htp_tx_t *tx = (htp_tx_t *)txv;
if (tx->request_headers == NULL)
return;
htp_header_t *h = (htp_header_t *)htp_table_get_c(tx->request_headers,
"User-Agent");
if (h == NULL || h->value == NULL) {
SCLogDebug("HTTP UA header not present in this request");
return;
}
const uint32_t buffer_len = bstr_len(h->value);
const uint8_t *buffer = bstr_ptr(h->value);
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);
}
}
int PrefilterTxUARegister(DetectEngineCtx *de_ctx,
SigGroupHead *sgh, MpmCtx *mpm_ctx)
{
SCEnter();
return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxUA,
ALPROTO_HTTP, HTP_REQUEST_HEADERS,
mpm_ctx, NULL, "http_user_agent");
}
/**
* \brief Do the http_user_agent content inspection for a signature.
*
* \param de_ctx Detection engine context.
* \param det_ctx Detection engine thread context.
* \param s Signature to inspect.
* \param f Flow.
* \param flags App layer flags.
* \param state App layer state.
*
* \retval 0 No match.
* \retval 1 Match.
*/
int DetectEngineInspectHttpUA(ThreadVars *tv,
DetectEngineCtx *de_ctx, DetectEngineThreadCtx *det_ctx,
const Signature *s, const SigMatchData *smd,
Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id)
{
htp_tx_t *tx = (htp_tx_t *)txv;
htp_header_t *h = (htp_header_t *)htp_table_get_c(tx->request_headers,
"User-Agent");
if (h == NULL) {
SCLogDebug("HTTP user agent header not present in this request");
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,
(uint8_t *)bstr_ptr(h->value),
bstr_len(h->value),
0, DETECT_CI_FLAGS_SINGLE,
DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE, NULL);
if (r == 1)
return DETECT_ENGINE_INSPECT_SIG_MATCH;
end:
if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP, tx, flags) > HTP_REQUEST_HEADERS)
return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH;
else
return DETECT_ENGINE_INSPECT_SIG_NO_MATCH;
}
/***********************************Unittests**********************************/
#ifdef UNITTESTS

1
src/detect-engine-register.h
Unescape Escape View File

@ -133,6 +133,7 @@ enum {
DETECT_AL_HTTP_STAT_MSG,
DETECT_AL_HTTP_STAT_CODE,
DETECT_AL_HTTP_USER_AGENT,
DETECT_HTTP_UA,
DETECT_AL_HTTP_HOST,
DETECT_AL_HTTP_RAW_HOST,
DETECT_AL_HTTP_REQUEST_LINE,

71
src/detect-http-ua.c
Unescape Escape View File

@ -39,6 +39,7 @@
#include "detect-engine.h"
#include "detect-engine-mpm.h"
#include "detect-engine-state.h"
#include "detect-engine-prefilter.h"
#include "detect-content.h"
#include "detect-pcre.h"
@ -62,26 +63,39 @@
static int DetectHttpUASetup(DetectEngineCtx *, Signature *, const char *);
static void DetectHttpUARegisterTests(void);
static int g_http_ua_buffer_id = 0;
static int DetectHttpUserAgentSetup(DetectEngineCtx *, Signature *, const char *);
static InspectionBuffer *GetData(DetectEngineThreadCtx *det_ctx,
const DetectEngineTransforms *transforms,
Flow *_f, const uint8_t _flow_flags,
void *txv, const int list_id);
/**
* \brief Registers the keyword handlers for the "http_user_agent" keyword.
*/
void DetectHttpUARegister(void)
{
/* http_user_agent content modifier */
sigmatch_table[DETECT_AL_HTTP_USER_AGENT].name = "http_user_agent";
sigmatch_table[DETECT_AL_HTTP_USER_AGENT].desc = "content modifier to match only on the HTTP User-Agent header";
sigmatch_table[DETECT_AL_HTTP_USER_AGENT].url = DOC_URL DOC_VERSION "/rules/http-keywords.html#http-user-agent";
sigmatch_table[DETECT_AL_HTTP_USER_AGENT].Setup = DetectHttpUASetup;
sigmatch_table[DETECT_AL_HTTP_USER_AGENT].RegisterTests = DetectHttpUARegisterTests;
sigmatch_table[DETECT_AL_HTTP_USER_AGENT].flags |= SIGMATCH_NOOPT;
DetectAppLayerMpmRegister("http_user_agent", SIG_FLAG_TOSERVER, 2,
PrefilterTxUARegister);
/* http.user_agent sticky buffer */
sigmatch_table[DETECT_HTTP_UA].name = "http.user_agent";
sigmatch_table[DETECT_HTTP_UA].desc = "sticky buffer to match specifically and only on the HTTP User Agent buffer";
sigmatch_table[DETECT_HTTP_UA].url = DOC_URL DOC_VERSION "/rules/http-keywords.html#http-user-agent";
sigmatch_table[DETECT_HTTP_UA].Setup = DetectHttpUserAgentSetup;
sigmatch_table[DETECT_HTTP_UA].flags |= SIGMATCH_NOOPT;
DetectAppLayerInspectEngineRegister2("http_user_agent", ALPROTO_HTTP,
SIG_FLAG_TOSERVER, HTP_REQUEST_HEADERS,
DetectEngineInspectBufferGeneric, GetData);
DetectAppLayerInspectEngineRegister("http_user_agent",
ALPROTO_HTTP, SIG_FLAG_TOSERVER, HTP_REQUEST_HEADERS,
DetectEngineInspectHttpUA);
DetectAppLayerMpmRegister2("http_user_agent", SIG_FLAG_TOSERVER, 2,
PrefilterGenericMpmRegister, GetData, ALPROTO_HTTP,
HTP_REQUEST_HEADERS);
DetectBufferTypeSetDescriptionByName("http_user_agent",
"http user agent");
@ -110,6 +124,51 @@ int DetectHttpUASetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg)
ALPROTO_HTTP);
}
/**
* \brief this function setup the http.user_agent 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 DetectHttpUserAgentSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str)
{
if (DetectBufferSetActiveList(s, g_http_ua_buffer_id) < 0)
return -1;
if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) < 0)
return -1;
return 0;
}
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_headers == NULL)
return NULL;
htp_header_t *h = (htp_header_t *)htp_table_get_c(tx->request_headers,
"User-Agent");
if (h == NULL || h->value == NULL) {
SCLogDebug("HTTP UA header not present in this request");
return NULL;
}
const uint32_t data_len = bstr_len(h->value);
const uint8_t *data = bstr_ptr(h->value);
InspectionBufferSetup(buffer, data, data_len);
InspectionBufferApplyTransforms(buffer, transforms);
}
return buffer;
}
/************************************Unittests*********************************/
#ifdef UNITTESTS

Write Preview
Loading…
Cancel
Save