diff options
Diffstat (limited to 'framework/src/suricata/src/detect-fileext.c')
-rw-r--r-- | framework/src/suricata/src/detect-fileext.c | 315 |
1 files changed, 315 insertions, 0 deletions
diff --git a/framework/src/suricata/src/detect-fileext.c b/framework/src/suricata/src/detect-fileext.c new file mode 100644 index 00000000..7b5e9103 --- /dev/null +++ b/framework/src/suricata/src/detect-fileext.c @@ -0,0 +1,315 @@ +/* Copyright (C) 2007-2012 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 "debug.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 "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-bm.h" +#include "util-print.h" +#include "util-memcmp.h" + +#include "app-layer.h" + +#include "stream-tcp.h" +#include "detect-fileext.h" + +static int DetectFileextMatch (ThreadVars *, DetectEngineThreadCtx *, Flow *, + uint8_t, File *, Signature *, SigMatch *); +static int DetectFileextSetup (DetectEngineCtx *, Signature *, char *); +static void DetectFileextRegisterTests(void); +static void DetectFileextFree(void *); + +/** + * \brief Registration function for keyword: fileext + */ +void DetectFileextRegister(void) +{ + sigmatch_table[DETECT_FILEEXT].name = "fileext"; + sigmatch_table[DETECT_FILEEXT].desc = "match on the extension of a file name"; + sigmatch_table[DETECT_FILEEXT].url = "https://redmine.openinfosecfoundation.org/projects/suricata/wiki/File-keywords#fileext"; + sigmatch_table[DETECT_FILEEXT].FileMatch = DetectFileextMatch; + sigmatch_table[DETECT_FILEEXT].alproto = ALPROTO_HTTP; + sigmatch_table[DETECT_FILEEXT].Setup = DetectFileextSetup; + sigmatch_table[DETECT_FILEEXT].Free = DetectFileextFree; + sigmatch_table[DETECT_FILEEXT].RegisterTests = DetectFileextRegisterTests; + + SCLogDebug("registering fileext rule option"); + return; +} + +/** + * \brief match the specified file extension + * + * \param t thread local vars + * \param det_ctx pattern matcher thread local data + * \param f *LOCKED* flow + * \param flags direction flags + * \param file file being inspected + * \param s signature being inspected + * \param m sigmatch that we will cast into DetectFileextData + * + * \retval 0 no match + * \retval 1 match + */ +static int DetectFileextMatch (ThreadVars *t, DetectEngineThreadCtx *det_ctx, + Flow *f, uint8_t flags, File *file, Signature *s, SigMatch *m) +{ + SCEnter(); + int ret = 0; + + DetectFileextData *fileext = (DetectFileextData *)m->ctx; + + if (file->name == NULL) + SCReturnInt(0); + + if (file->txid < det_ctx->tx_id) + SCReturnInt(0); + + if (file->txid > det_ctx->tx_id) + SCReturnInt(0); + + if (file->name_len <= fileext->len) + SCReturnInt(0); + + int offset = file->name_len - fileext->len; + + /* fileext->ext is already in lowercase, as SCMemcmpLowercase requires */ + if (file->name[offset - 1] == '.' && + SCMemcmpLowercase(fileext->ext, file->name + offset, fileext->len) == 0) + { + if (!(fileext->flags & DETECT_CONTENT_NEGATED)) { + ret = 1; + SCLogDebug("File ext found"); + } + } + + if (ret == 0 && (fileext->flags & DETECT_CONTENT_NEGATED)) { + SCLogDebug("negated match"); + ret = 1; + } + + SCReturnInt(ret); +} + +/** + * \brief This function is used to parse fileet + * + * \param str Pointer to the fileext value string + * + * \retval pointer to DetectFileextData on success + * \retval NULL on failure + */ +static DetectFileextData *DetectFileextParse (char *str) +{ + DetectFileextData *fileext = NULL; + + /* We have a correct filename option */ + fileext = SCMalloc(sizeof(DetectFileextData)); + if (unlikely(fileext == NULL)) + goto error; + + memset(fileext, 0x00, sizeof(DetectFileextData)); + + if (DetectContentDataParse("fileext", str, &fileext->ext, &fileext->len, &fileext->flags) == -1) { + goto error; + } + uint16_t u; + for (u = 0; u < fileext->len; u++) + fileext->ext[u] = tolower(fileext->ext[u]); + + SCLogDebug("flags %02X", fileext->flags); + if (fileext->flags & DETECT_CONTENT_NEGATED) { + SCLogDebug("negated fileext"); + } + +#ifdef DEBUG + if (SCLogDebugEnabled()) { + char *ext = SCMalloc(fileext->len + 1); + if (ext != NULL) { + memcpy(ext, fileext->ext, fileext->len); + ext[fileext->len] = '\0'; + SCLogDebug("will look for fileext %s", ext); + } + } +#endif + + return fileext; + +error: + if (fileext != NULL) + DetectFileextFree(fileext); + return NULL; + +} + +/** + * \brief this function is used to add the parsed "id" option + * into the current signature + * + * \param de_ctx pointer to the Detection Engine Context + * \param s pointer to the Current Signature + * \param idstr pointer to the user provided "id" option + * + * \retval 0 on Success + * \retval -1 on Failure + */ +static int DetectFileextSetup (DetectEngineCtx *de_ctx, Signature *s, char *str) +{ + DetectFileextData *fileext= NULL; + SigMatch *sm = NULL; + + fileext = DetectFileextParse(str); + if (fileext == NULL) + goto error; + + /* Okay so far so good, lets get this into a SigMatch + * and put it in the Signature. */ + sm = SigMatchAlloc(); + if (sm == NULL) + goto error; + + sm->type = DETECT_FILEEXT; + sm->ctx = (void *)fileext; + + SigMatchAppendSMToList(s, sm, DETECT_SM_LIST_FILEMATCH); + + if (s->alproto != ALPROTO_HTTP && s->alproto != ALPROTO_SMTP) { + SCLogError(SC_ERR_CONFLICTING_RULE_KEYWORDS, "rule contains conflicting keywords."); + goto error; + } + + if (s->alproto == ALPROTO_HTTP) { + AppLayerHtpNeedFileInspection(); + } + + s->file_flags |= (FILE_SIG_NEED_FILE|FILE_SIG_NEED_FILENAME); + return 0; + +error: + if (fileext != NULL) + DetectFileextFree(fileext); + if (sm != NULL) + SCFree(sm); + return -1; + +} + +/** + * \brief this function will free memory associated with DetectFileextData + * + * \param fileext pointer to DetectFileextData + */ +static void DetectFileextFree(void *ptr) +{ + if (ptr != NULL) { + DetectFileextData *fileext = (DetectFileextData *)ptr; + if (fileext->ext != NULL) + SCFree(fileext->ext); + SCFree(fileext); + } +} + +#ifdef UNITTESTS /* UNITTESTS */ + +/** + * \test DetectFileextTestParse01 + */ +int DetectFileextTestParse01 (void) +{ + DetectFileextData *dfd = DetectFileextParse("\"doc\""); + if (dfd != NULL) { + DetectFileextFree(dfd); + return 1; + } + return 0; +} + +/** + * \test DetectFileextTestParse02 + */ +int DetectFileextTestParse02 (void) +{ + int result = 0; + + DetectFileextData *dfd = DetectFileextParse("\"tar.gz\""); + if (dfd != NULL) { + if (dfd->len == 6 && memcmp(dfd->ext, "tar.gz", 6) == 0) { + result = 1; + } + + DetectFileextFree(dfd); + return result; + } + return 0; +} + +/** + * \test DetectFileextTestParse03 + */ +int DetectFileextTestParse03 (void) +{ + int result = 0; + + DetectFileextData *dfd = DetectFileextParse("\"pdf\""); + if (dfd != NULL) { + if (dfd->len == 3 && memcmp(dfd->ext, "pdf", 3) == 0) { + result = 1; + } + + DetectFileextFree(dfd); + return result; + } + return 0; +} + +#endif /* UNITTESTS */ + +/** + * \brief this function registers unit tests for DetectFileext + */ +void DetectFileextRegisterTests(void) +{ +#ifdef UNITTESTS /* UNITTESTS */ + UtRegisterTest("DetectFileextTestParse01", DetectFileextTestParse01, 1); + UtRegisterTest("DetectFileextTestParse02", DetectFileextTestParse02, 1); + UtRegisterTest("DetectFileextTestParse03", DetectFileextTestParse03, 1); +#endif /* UNITTESTS */ +} |