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Diffstat (limited to '')
| -rw-r--r-- | src/detect-filename.c | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/src/detect-filename.c b/src/detect-filename.c new file mode 100644 index 0000000..fc6e2fc --- /dev/null +++ b/src/detect-filename.c @@ -0,0 +1,372 @@ +/* Copyright (C) 2007-2022 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 <victor@inliniac.net> + * \author Pablo Rincon <pablo.rincon.crespo@gmail.com> + * + */ + +#include "suricata-common.h" +#include "threads.h" +#include "decode.h" + +#include "detect.h" + +#include "detect-engine.h" +#include "detect-engine-mpm.h" +#include "detect-engine-state.h" +#include "detect-engine-file.h" +#include "detect-engine-prefilter.h" +#include "detect-engine-content-inspection.h" + +#include "detect-parse.h" +#include "detect-content.h" +#include "detect-file-data.h" + +#include "flow.h" +#include "flow-var.h" +#include "flow-util.h" + +#include "util-debug.h" +#include "util-spm-bm.h" +#include "util-unittest.h" +#include "util-unittest-helper.h" +#include "util-profiling.h" + +#include "app-layer.h" +#include "app-layer-htp.h" + +#include "stream-tcp.h" + +#include "detect-filename.h" +#include "app-layer-parser.h" + +static int DetectFileextSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str); +static int DetectFilenameSetup (DetectEngineCtx *, Signature *, const char *); +static int DetectFilenameSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str); +#ifdef UNITTESTS +static void DetectFilenameRegisterTests(void); +#endif +static int g_file_match_list_id = 0; +static int g_file_name_buffer_id = 0; + +static int PrefilterMpmFilenameRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, + const DetectBufferMpmRegistry *mpm_reg, int list_id); +static uint8_t DetectEngineInspectFilename(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); + +/** + * \brief Registration function for keyword: filename + */ +void DetectFilenameRegister(void) +{ + sigmatch_table[DETECT_FILENAME].name = "filename"; + sigmatch_table[DETECT_FILENAME].desc = "match on the file name"; + sigmatch_table[DETECT_FILENAME].url = "/rules/file-keywords.html#filename"; + sigmatch_table[DETECT_FILENAME].Setup = DetectFilenameSetup; +#ifdef UNITTESTS + sigmatch_table[DETECT_FILENAME].RegisterTests = DetectFilenameRegisterTests; +#endif + sigmatch_table[DETECT_FILENAME].flags = SIGMATCH_QUOTES_OPTIONAL|SIGMATCH_HANDLE_NEGATION; + sigmatch_table[DETECT_FILENAME].alternative = DETECT_FILE_NAME; + + sigmatch_table[DETECT_FILEEXT].name = "fileext"; + sigmatch_table[DETECT_FILEEXT].desc = "match on the extension of a file name"; + sigmatch_table[DETECT_FILEEXT].url = "/rules/file-keywords.html#fileext"; + sigmatch_table[DETECT_FILEEXT].Setup = DetectFileextSetup; + sigmatch_table[DETECT_FILEEXT].flags = SIGMATCH_QUOTES_OPTIONAL | SIGMATCH_HANDLE_NEGATION; + sigmatch_table[DETECT_FILEEXT].alternative = DETECT_FILE_NAME; + + sigmatch_table[DETECT_FILE_NAME].name = "file.name"; + sigmatch_table[DETECT_FILE_NAME].desc = "sticky buffer to match on the file name"; + sigmatch_table[DETECT_FILE_NAME].url = "/rules/file-keywords.html#filename"; + sigmatch_table[DETECT_FILE_NAME].Setup = DetectFilenameSetupSticky; + sigmatch_table[DETECT_FILE_NAME].flags = SIGMATCH_NOOPT|SIGMATCH_INFO_STICKY_BUFFER; + + DetectBufferTypeSetDescriptionByName("file.name", "file name"); + + g_file_match_list_id = DetectBufferTypeRegister("files"); + g_file_name_buffer_id = DetectBufferTypeRegister("file.name"); + + SCLogDebug("registering filename rule option"); + filehandler_table[DETECT_FILENAME].name = "files"; + filehandler_table[DETECT_FILENAME].priority = 0; + filehandler_table[DETECT_FILENAME].PrefilterFn = NULL; + filehandler_table[DETECT_FILENAME].Callback = DetectFileInspectGeneric; + + filehandler_table[DETECT_FILE_NAME].name = "file.name"; + filehandler_table[DETECT_FILE_NAME].priority = 2; + filehandler_table[DETECT_FILE_NAME].PrefilterFn = PrefilterMpmFilenameRegister; + filehandler_table[DETECT_FILE_NAME].Callback = DetectEngineInspectFilename; + + DetectBufferTypeSupportsMultiInstance("file.name"); + return; +} + +static int DetectFileextSetup(DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + if (s->init_data->transforms.cnt) { + SCLogError("previous transforms not consumed before 'fileext'"); + SCReturnInt(-1); + } + s->init_data->list = DETECT_SM_LIST_NOTSET; + s->file_flags |= (FILE_SIG_NEED_FILE | FILE_SIG_NEED_FILENAME); + + size_t dotstr_len = strlen(str) + 2; + char *dotstr = SCCalloc(1, dotstr_len); + if (dotstr == NULL) + return -1; + dotstr[0] = '.'; + strlcat(dotstr, str, dotstr_len); + + if (DetectContentSetup(de_ctx, s, dotstr) < 0) { + SCFree(dotstr); + return -1; + } + SCFree(dotstr); + + SigMatch *sm = DetectGetLastSMFromLists(s, DETECT_CONTENT, -1); + if (sm == NULL) + return -1; + + DetectContentData *cd = (DetectContentData *)sm->ctx; + cd->flags |= DETECT_CONTENT_ENDS_WITH; + if (DetectContentConvertToNocase(de_ctx, cd) != 0) + return -1; + if (DetectEngineContentModifierBufferSetup( + de_ctx, s, NULL, DETECT_FILE_NAME, g_file_name_buffer_id, s->alproto) < 0) + return -1; + + return 0; +} +/** + * \brief this function is used to parse filename options + * \brief 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 "filename" option + * + * \retval 0 on Success + * \retval -1 on Failure + */ +static int DetectFilenameSetup (DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + if (s->init_data->transforms.cnt) { + SCLogError("previous transforms not consumed before 'filename'"); + SCReturnInt(-1); + } + s->init_data->list = DETECT_SM_LIST_NOTSET; + s->file_flags |= (FILE_SIG_NEED_FILE | FILE_SIG_NEED_FILENAME); + + if (DetectContentSetup(de_ctx, s, str) < 0) { + return -1; + } + + SigMatch *sm = DetectGetLastSMFromLists(s, DETECT_CONTENT, -1); + if (sm == NULL) + return -1; + + DetectContentData *cd = (DetectContentData *)sm->ctx; + if (DetectContentConvertToNocase(de_ctx, cd) != 0) + return -1; + if (DetectEngineContentModifierBufferSetup( + de_ctx, s, NULL, DETECT_FILE_NAME, g_file_name_buffer_id, s->alproto) < 0) + return -1; + + return 0; +} + +/* file.name implementation */ + +/** + * \brief this function setup the file.data 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 DetectFilenameSetupSticky(DetectEngineCtx *de_ctx, Signature *s, const char *str) +{ + if (DetectBufferSetActiveList(de_ctx, s, g_file_name_buffer_id) < 0) + return -1; + s->file_flags |= (FILE_SIG_NEED_FILE | FILE_SIG_NEED_FILENAME); + return 0; +} + +static InspectionBuffer *FilenameGetDataCallback(DetectEngineThreadCtx *det_ctx, + const DetectEngineTransforms *transforms, Flow *f, uint8_t flow_flags, File *cur_file, + int list_id, int local_file_id) +{ + SCEnter(); + + InspectionBuffer *buffer = InspectionBufferMultipleForListGet(det_ctx, list_id, local_file_id); + if (buffer == NULL) + return NULL; + if (buffer->initialized) + return buffer; + + const uint8_t *data = cur_file->name; + uint32_t data_len = cur_file->name_len; + + InspectionBufferSetupMulti(buffer, transforms, data, data_len); + + SCReturnPtr(buffer, "InspectionBuffer"); +} + +static uint8_t DetectEngineInspectFilename(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) +{ + const DetectEngineTransforms *transforms = NULL; + if (!engine->mpm) { + transforms = engine->v2.transforms; + } + + AppLayerGetFileState files = AppLayerParserGetTxFiles(f, alstate, txv, flags); + FileContainer *ffc = files.fc; + if (ffc == NULL) { + return DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES; + } + + uint8_t r = DETECT_ENGINE_INSPECT_SIG_NO_MATCH; + int local_file_id = 0; + for (File *file = ffc->head; file != NULL; file = file->next) { + InspectionBuffer *buffer = FilenameGetDataCallback( + det_ctx, transforms, f, flags, file, engine->sm_list, local_file_id); + if (buffer == NULL) + continue; + + det_ctx->buffer_offset = 0; + det_ctx->discontinue_matching = 0; + det_ctx->inspection_recursion_counter = 0; + int match = DetectEngineContentInspection(de_ctx, det_ctx, s, engine->smd, + NULL, f, + (uint8_t *)buffer->inspect, + buffer->inspect_len, + buffer->inspect_offset, DETECT_CI_FLAGS_SINGLE, + DETECT_ENGINE_CONTENT_INSPECTION_MODE_STATE); + if (match == 1) { + return DETECT_ENGINE_INSPECT_SIG_MATCH; + } else { + r = DETECT_ENGINE_INSPECT_SIG_CANT_MATCH_FILES; + } + local_file_id++; + } + return r; +} + +typedef struct PrefilterMpmFilename { + int list_id; + const MpmCtx *mpm_ctx; + const DetectEngineTransforms *transforms; +} PrefilterMpmFilename; + +/** \brief Filedata Filedata 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 PrefilterTxFilename(DetectEngineThreadCtx *det_ctx, const void *pectx, Packet *p, + Flow *f, void *txv, const uint64_t idx, const AppLayerTxData *txd, const uint8_t flags) +{ + SCEnter(); + + if (!AppLayerParserHasFilesInDir(txd, flags)) + return; + + const PrefilterMpmFilename *ctx = (const PrefilterMpmFilename *)pectx; + const MpmCtx *mpm_ctx = ctx->mpm_ctx; + const int list_id = ctx->list_id; + + AppLayerGetFileState files = AppLayerParserGetTxFiles(f, f->alstate, txv, flags); + FileContainer *ffc = files.fc; + if (ffc != NULL) { + int local_file_id = 0; + for (File *file = ffc->head; file != NULL; file = file->next) { + InspectionBuffer *buffer = FilenameGetDataCallback( + det_ctx, ctx->transforms, f, flags, file, list_id, local_file_id); + if (buffer == NULL) + continue; + + 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); + } + local_file_id++; + } + } +} + +static void PrefilterMpmFilenameFree(void *ptr) +{ + SCFree(ptr); +} + +static int PrefilterMpmFilenameRegister(DetectEngineCtx *de_ctx, SigGroupHead *sgh, MpmCtx *mpm_ctx, + const DetectBufferMpmRegistry *mpm_reg, int list_id) +{ + PrefilterMpmFilename *pectx = SCCalloc(1, sizeof(*pectx)); + if (pectx == NULL) + return -1; + pectx->list_id = list_id; + pectx->mpm_ctx = mpm_ctx; + pectx->transforms = &mpm_reg->transforms; + + return PrefilterAppendTxEngine(de_ctx, sgh, PrefilterTxFilename, + mpm_reg->app_v2.alproto, mpm_reg->app_v2.tx_min_progress, + pectx, PrefilterMpmFilenameFree, mpm_reg->pname); +} + +#ifdef UNITTESTS /* UNITTESTS */ + +/** + * \test Test parser accepting valid rules and rejecting invalid rules + */ +static int DetectFilenameSignatureParseTest01(void) +{ + FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; sid:1;)", true)); + FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; nocase; sid:1;)", true)); + FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; endswith; sid:1;)", true)); + FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; startswith; sid:1;)", true)); + FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; startswith; endswith; sid:1;)", true)); + FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; bsize:10; sid:1;)", true)); + + FAIL_IF_NOT(UTHParseSignature("alert http any any -> any any (flow:to_client; file.name; content:\"abc\"; rawbytes; sid:1;)", false)); + FAIL_IF_NOT(UTHParseSignature("alert tcp any any -> any any (flow:to_client; file.name; sid:1;)", false)); + //FAIL_IF_NOT(UTHParseSignature("alert tls any any -> any any (flow:to_client; file.name; content:\"abc\"; sid:1;)", false)); + PASS; +} +/** + * \brief this function registers unit tests for DetectFilename + */ +void DetectFilenameRegisterTests(void) +{ + UtRegisterTest("DetectFilenameSignatureParseTest01", DetectFilenameSignatureParseTest01); +} +#endif /* UNITTESTS */ |