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Diffstat (limited to 'src/detect-http-client-body.c')
| -rw-r--r-- | src/detect-http-client-body.c | 405 |
1 files changed, 405 insertions, 0 deletions
diff --git a/src/detect-http-client-body.c b/src/detect-http-client-body.c new file mode 100644 index 0000000..41b2552 --- /dev/null +++ b/src/detect-http-client-body.c @@ -0,0 +1,405 @@ +/* Copyright (C) 2007-2021 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 Anoop Saldanha <anoopsaldanha@gmail.com> + * + * Implements support for the http_client_body 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-state.h" +#include "detect-engine-prefilter.h" +#include "detect-engine-content-inspection.h" +#include "detect-content.h" +#include "detect-pcre.h" +// PrefilterMpmFiledata +#include "detect-file-data.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-client-body.h" +#include "stream-tcp.h" +#include "util-profiling.h" + +static int DetectHttpClientBodySetup(DetectEngineCtx *, Signature *, const char *); +static int DetectHttpClientBodySetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str); +#ifdef UNITTESTS +static void DetectHttpClientBodyRegisterTests(void); +#endif +static void DetectHttpClientBodySetupCallback(const DetectEngineCtx *de_ctx, + Signature *s); +static int g_http_client_body_buffer_id = 0; + +static uint8_t DetectEngineInspectBufferHttpBody(DetectEngineCtx *de_ctx, + DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine, + const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id); + +static int PrefilterMpmHttpRequestBodyRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, + MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id); + +/** + * \brief Registers the keyword handlers for the "http_client_body" keyword. + */ +void DetectHttpClientBodyRegister(void) +{ + /* http_client_body content modifier */ + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].name = "http_client_body"; + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].desc = "content modifier to match only on HTTP request-body"; + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].url = "/rules/http-keywords.html#http-client-body"; + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].Setup = DetectHttpClientBodySetup; +#ifdef UNITTESTS + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].RegisterTests = DetectHttpClientBodyRegisterTests; +#endif + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].flags |= SIGMATCH_NOOPT ; + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].flags |= SIGMATCH_INFO_CONTENT_MODIFIER; + sigmatch_table[DETECT_AL_HTTP_CLIENT_BODY].alternative = DETECT_HTTP_REQUEST_BODY; + + /* http.request_body sticky buffer */ + sigmatch_table[DETECT_HTTP_REQUEST_BODY].name = "http.request_body"; + sigmatch_table[DETECT_HTTP_REQUEST_BODY].desc = "sticky buffer to match the HTTP request body buffer"; + sigmatch_table[DETECT_HTTP_REQUEST_BODY].url = "/rules/http-keywords.html#http-client-body"; + sigmatch_table[DETECT_HTTP_REQUEST_BODY].Setup = DetectHttpClientBodySetupSticky; + sigmatch_table[DETECT_HTTP_REQUEST_BODY].flags |= SIGMATCH_NOOPT; + sigmatch_table[DETECT_HTTP_REQUEST_BODY].flags |= SIGMATCH_INFO_STICKY_BUFFER; + + DetectAppLayerInspectEngineRegister2("http_client_body", ALPROTO_HTTP1, SIG_FLAG_TOSERVER, + HTP_REQUEST_BODY, DetectEngineInspectBufferHttpBody, NULL); + + DetectAppLayerMpmRegister2("http_client_body", SIG_FLAG_TOSERVER, 2, + PrefilterMpmHttpRequestBodyRegister, NULL, ALPROTO_HTTP1, HTP_REQUEST_BODY); + + DetectAppLayerInspectEngineRegister2("http_client_body", ALPROTO_HTTP2, SIG_FLAG_TOSERVER, + HTTP2StateDataClient, DetectEngineInspectFiledata, NULL); + DetectAppLayerMpmRegister2("http_client_body", SIG_FLAG_TOSERVER, 2, + PrefilterMpmFiledataRegister, NULL, ALPROTO_HTTP2, HTTP2StateDataClient); + + DetectBufferTypeSetDescriptionByName("http_client_body", + "http request body"); + + DetectBufferTypeRegisterSetupCallback("http_client_body", + DetectHttpClientBodySetupCallback); + + g_http_client_body_buffer_id = DetectBufferTypeGetByName("http_client_body"); +} + +static void DetectHttpClientBodySetupCallback(const DetectEngineCtx *de_ctx, + Signature *s) +{ + SCLogDebug("callback invoked by %u", s->id); + AppLayerHtpEnableRequestBodyCallback(); + + /* client body needs to be inspected in sync with stream if possible */ + s->init_data->init_flags |= SIG_FLAG_INIT_NEED_FLUSH; +} + +/** + * \brief The setup function for the http_client_body keyword for a signature. + * + * \param de_ctx Pointer to the detection engine context. + * \param s Pointer to signature for the current Signature being parsed + * from the rules. + * \param m Pointer to the head of the SigMatchs for the current rule + * being parsed. + * \param arg Pointer to the string holding the keyword value. + * + * \retval 0 On success + * \retval -1 On failure + */ +int DetectHttpClientBodySetup(DetectEngineCtx *de_ctx, Signature *s, const char *arg) +{ + return DetectEngineContentModifierBufferSetup(de_ctx, s, arg, DETECT_AL_HTTP_CLIENT_BODY, + g_http_client_body_buffer_id, ALPROTO_HTTP1); +} + +/** + * \brief this function setup the http.request_body 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 DetectHttpClientBodySetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + if (DetectBufferSetActiveList(de_ctx, s, g_http_client_body_buffer_id) < 0) + return -1; + if (DetectSignatureSetAppProto(s, ALPROTO_HTTP) < 0) + return -1; + return 0; +} + +static inline HtpBody *GetRequestBody(htp_tx_t *tx) +{ + HtpTxUserData *htud = (HtpTxUserData *)htp_tx_get_user_data(tx); + if (htud == NULL) { + SCLogDebug("no htud"); + return NULL; + } + + return &htud->request_body; +} + +typedef struct PrefilterMpmHttpRequestBody { + int list_id; + int base_list_id; + const MpmCtx *mpm_ctx; + const DetectEngineTransforms *transforms; +} PrefilterMpmHttpRequestBody; + +static void PrefilterMpmHttpRequestBodyFree(void *ptr) +{ + SCFree(ptr); +} + +static inline InspectionBuffer *HttpRequestBodyXformsGetDataCallback(DetectEngineThreadCtx *det_ctx, + const DetectEngineTransforms *transforms, const int list_id, InspectionBuffer *base_buffer) +{ + InspectionBuffer *buffer = InspectionBufferGet(det_ctx, list_id); + if (buffer->inspect != NULL) + return buffer; + + InspectionBufferSetup(det_ctx, list_id, buffer, base_buffer->inspect, base_buffer->inspect_len); + buffer->inspect_offset = base_buffer->inspect_offset; + InspectionBufferApplyTransforms(buffer, transforms); + SCLogDebug("xformed buffer %p size %u", buffer, buffer->inspect_len); + SCReturnPtr(buffer, "InspectionBuffer"); +} + +static InspectionBuffer *HttpRequestBodyGetDataCallback(DetectEngineThreadCtx *det_ctx, + const DetectEngineTransforms *transforms, Flow *f, const uint8_t flow_flags, void *txv, + const int list_id, const int base_id) +{ + SCEnter(); + + InspectionBuffer *buffer = InspectionBufferGet(det_ctx, base_id); + if (base_id != list_id && buffer->inspect != NULL) + return HttpRequestBodyXformsGetDataCallback(det_ctx, transforms, list_id, buffer); + else if (buffer->inspect != NULL) + return buffer; + + htp_tx_t *tx = txv; + HtpState *htp_state = f->alstate; + const uint8_t flags = flow_flags; + + HtpBody *body = GetRequestBody(tx); + if (body == NULL) { + return NULL; + } + + /* no new data */ + if (body->body_inspected == body->content_len_so_far) { + SCLogDebug("no new data"); + return NULL; + } + + HtpBodyChunk *cur = body->first; + if (cur == NULL) { + SCLogDebug("No http chunks to inspect for this transaction"); + return NULL; + } + + SCLogDebug("request.body_limit %u request_body.content_len_so_far %" PRIu64 + ", request.inspect_min_size %" PRIu32 ", EOF %s, progress > body? %s", + htp_state->cfg->request.body_limit, body->content_len_so_far, + htp_state->cfg->request.inspect_min_size, flags & STREAM_EOF ? "true" : "false", + (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, tx, flags) > + HTP_REQUEST_BODY) + ? "true" + : "false"); + + if (!htp_state->cfg->http_body_inline) { + /* inspect the body if the transfer is complete or we have hit + * our body size limit */ + if ((htp_state->cfg->request.body_limit == 0 || + body->content_len_so_far < htp_state->cfg->request.body_limit) && + body->content_len_so_far < htp_state->cfg->request.inspect_min_size && + !(AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, tx, flags) > + HTP_REQUEST_BODY) && + !(flags & STREAM_EOF)) { + SCLogDebug("we still haven't seen the entire request body. " + "Let's defer body inspection till we see the " + "entire body."); + return NULL; + } + } + + /* get the inspect buffer + * + * make sure that we have at least the configured inspect_win size. + * If we have more, take at least 1/4 of the inspect win size before + * the new data. + */ + uint64_t offset = 0; + if (body->body_inspected > htp_state->cfg->request.inspect_min_size) { + BUG_ON(body->content_len_so_far < body->body_inspected); + uint64_t inspect_win = body->content_len_so_far - body->body_inspected; + SCLogDebug("inspect_win %"PRIu64, inspect_win); + if (inspect_win < htp_state->cfg->request.inspect_window) { + uint64_t inspect_short = htp_state->cfg->request.inspect_window - inspect_win; + if (body->body_inspected < inspect_short) + offset = 0; + else + offset = body->body_inspected - inspect_short; + } else { + offset = body->body_inspected - (htp_state->cfg->request.inspect_window / 4); + } + } + + const uint8_t *data; + uint32_t data_len; + + StreamingBufferGetDataAtOffset(body->sb, + &data, &data_len, offset); + InspectionBufferSetup(det_ctx, base_id, buffer, data, data_len); + buffer->inspect_offset = offset; + body->body_inspected = body->content_len_so_far; + SCLogDebug("body->body_inspected now: %" PRIu64, body->body_inspected); + + if (base_id != list_id) { + buffer = HttpRequestBodyXformsGetDataCallback(det_ctx, transforms, list_id, buffer); + } + SCReturnPtr(buffer, "InspectionBuffer"); +} + +static uint8_t DetectEngineInspectBufferHttpBody(DetectEngineCtx *de_ctx, + DetectEngineThreadCtx *det_ctx, const DetectEngineAppInspectionEngine *engine, + const Signature *s, Flow *f, uint8_t flags, void *alstate, void *txv, uint64_t tx_id) +{ + bool eof = + (AppLayerParserGetStateProgress(f->proto, f->alproto, txv, flags) > engine->progress); + const InspectionBuffer *buffer = HttpRequestBodyGetDataCallback( + det_ctx, engine->v2.transforms, f, flags, txv, engine->sm_list, engine->sm_list_base); + if (buffer == NULL || buffer->inspect == NULL) { + return eof ? DETECT_ENGINE_INSPECT_SIG_CANT_MATCH : DETECT_ENGINE_INSPECT_SIG_NO_MATCH; + } + + const uint32_t data_len = buffer->inspect_len; + const uint8_t *data = buffer->inspect; + const uint64_t offset = buffer->inspect_offset; + + uint8_t ci_flags = eof ? DETECT_CI_FLAGS_END : 0; + ci_flags |= (offset == 0 ? DETECT_CI_FLAGS_START : 0); + ci_flags |= buffer->flags; + + det_ctx->discontinue_matching = 0; + det_ctx->buffer_offset = 0; + det_ctx->inspection_recursion_counter = 0; + + /* Inspect all the uricontents fetched on each + * transaction at the app layer */ + int r = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd, NULL, f, (uint8_t *)data, + data_len, offset, ci_flags, DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE); + if (r == 1) { + return DETECT_ENGINE_INSPECT_SIG_MATCH; + } + + if (flags & STREAM_TOSERVER) { + if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, txv, flags) > + HTP_REQUEST_BODY) + return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH; + } else { + if (AppLayerParserGetStateProgress(IPPROTO_TCP, ALPROTO_HTTP1, txv, flags) > + HTP_RESPONSE_BODY) + return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH; + } + return DETECT_ENGINE_INSPECT_SIG_NO_MATCH; +} + +/** \brief HTTP Request body callback + * + * \param det_ctx detection engine thread ctx + * \param pectx inspection context + * \param p packet to inspect + * \param f flow to inspect + * \param txv tx to inspect + * \param idx transaction id + * \param flags STREAM_* flags including direction + */ +static void PrefilterTxHttpRequestBody(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p, + Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *_txd, const uint8_t flags) +{ + SCEnter(); + + const PrefilterMpmHttpRequestBody *ctx = (const PrefilterMpmHttpRequestBody *)pectx; + const MpmCtx *mpm_ctx = ctx->mpm_ctx; + const int list_id = ctx->list_id; + + InspectionBuffer *buffer = HttpRequestBodyGetDataCallback( + det_ctx, ctx->transforms, f, flags, txv, list_id, ctx->base_list_id); + if (buffer == NULL) + return; + + if (buffer->inspect_len >= mpm_ctx->minlen) { + (void)mpm_table[mpm_ctx->mpm_type].Search( + mpm_ctx, &det_ctx->mtcu, &det_ctx->pmq, buffer->inspect, buffer->inspect_len); + PREFILTER_PROFILING_ADD_BYTES(det_ctx, buffer->inspect_len); + } +} + +static int PrefilterMpmHttpRequestBodyRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, + MpmCtx *mpm_ctx, const DetectBufferMpmRegistry *mpm_reg, int list_id) +{ + PrefilterMpmHttpRequestBody *pectx = SCCalloc(1, sizeof(*pectx)); + if (pectx == NULL) + return -1; + pectx->list_id = list_id; + pectx->base_list_id = mpm_reg->sm_list_base; + SCLogDebug("list_id %d base_list_id %d", list_id, pectx->base_list_id); + pectx->mpm_ctx = mpm_ctx; + pectx->transforms = &mpm_reg->transforms; + + return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxHttpRequestBody, mpm_reg->app_v2.alproto, + mpm_reg->app_v2.tx_min_progress, pectx, PrefilterMpmHttpRequestBodyFree, + mpm_reg->pname); +} + +#ifdef UNITTESTS +#include "detect-engine-alert.h" +#include "tests/detect-http-client-body.c" +#endif /* UNITTESTS */ + +/** + * @} + */ |