diff options
Diffstat (limited to 'framework/src/suricata/src/detect-distance.c')
| -rw-r--r-- | framework/src/suricata/src/detect-distance.c | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/framework/src/suricata/src/detect-distance.c b/framework/src/suricata/src/detect-distance.c new file mode 100644 index 00000000..a8284dbe --- /dev/null +++ b/framework/src/suricata/src/detect-distance.c @@ -0,0 +1,270 @@ +/* Copyright (C) 2007-2010 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 Anoop Saldanha <anoopsaldanha@gmail.com> + * + * Implements the distance keyword + */ + +#include "suricata-common.h" + +#include "decode.h" + +#include "detect.h" +#include "detect-parse.h" +#include "detect-engine.h" +#include "app-layer.h" +#include "detect-parse.h" + +#include "detect-content.h" +#include "detect-uricontent.h" +#include "detect-pcre.h" +#include "detect-byte-extract.h" + +#include "flow-var.h" + +#include "util-debug.h" +#include "util-unittest.h" +#include "detect-bytejump.h" +#include "util-unittest-helper.h" + +static int DetectDistanceSetup(DetectEngineCtx *, Signature *, char *); +void DetectDistanceRegisterTests(void); + +void DetectDistanceRegister(void) +{ + sigmatch_table[DETECT_DISTANCE].name = "distance"; + sigmatch_table[DETECT_DISTANCE].desc = "indicates a relation between this content keyword and the content preceding it"; + sigmatch_table[DETECT_DISTANCE].url = "https://redmine.openinfosecfoundation.org/projects/suricata/wiki/Payload_keywords#Distance"; + sigmatch_table[DETECT_DISTANCE].Match = NULL; + sigmatch_table[DETECT_DISTANCE].Setup = DetectDistanceSetup; + sigmatch_table[DETECT_DISTANCE].Free = NULL; + sigmatch_table[DETECT_DISTANCE].RegisterTests = DetectDistanceRegisterTests; + + sigmatch_table[DETECT_DISTANCE].flags |= SIGMATCH_PAYLOAD; +} + +static int DetectDistanceSetup (DetectEngineCtx *de_ctx, Signature *s, + char *distancestr) +{ + char *str = distancestr; + char dubbed = 0; + SigMatch *pm = NULL; + int ret = -1; + + /* strip "'s */ + if (distancestr[0] == '\"' && distancestr[strlen(distancestr) - 1] == '\"') { + str = SCStrdup(distancestr + 1); + if (unlikely(str == NULL)) + goto end; + str[strlen(distancestr) - 2] = '\0'; + dubbed = 1; + } + + /* retrive the sm to apply the depth against */ + if (s->list != DETECT_SM_LIST_NOTSET) { + pm = SigMatchGetLastSMFromLists(s, 2, DETECT_CONTENT, s->sm_lists_tail[s->list]); + } else { + pm = SigMatchGetLastSMFromLists(s, 28, + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_PMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_UMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HRUDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HCBDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_FILEDATA], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HHDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HRHDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HMDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HCDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HSCDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HSMDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HUADMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HHHDMATCH], + DETECT_CONTENT, s->sm_lists_tail[DETECT_SM_LIST_HRHHDMATCH]); + } + if (pm == NULL) { + SCLogError(SC_ERR_OFFSET_MISSING_CONTENT, "distance needs " + "preceding content, uricontent option, http_client_body, " + "http_server_body, http_header option, http_raw_header option, " + "http_method option, http_cookie, http_raw_uri, " + "http_stat_msg, http_stat_code, http_user_agent or " + "file_data/dce_stub_data sticky buffer option"); + goto end; + } + + /* verify other conditions */ + DetectContentData *cd = (DetectContentData *)pm->ctx; + if (cd->flags & DETECT_CONTENT_DISTANCE) { + SCLogError(SC_ERR_INVALID_SIGNATURE, "can't use multiple distances for the same content."); + goto end; + } + if ((cd->flags & DETECT_CONTENT_DEPTH) || (cd->flags & DETECT_CONTENT_OFFSET)) { + SCLogError(SC_ERR_INVALID_SIGNATURE, "can't use a relative " + "keyword like within/distance with a absolute " + "relative keyword like depth/offset for the same " + "content." ); + goto end; + } + if (cd->flags & DETECT_CONTENT_NEGATED && cd->flags & DETECT_CONTENT_FAST_PATTERN) { + SCLogError(SC_ERR_INVALID_SIGNATURE, "can't have a relative " + "negated keyword set along with a fast_pattern"); + goto end; + } + if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) { + SCLogError(SC_ERR_INVALID_SIGNATURE, "can't have a relative " + "keyword set along with a fast_pattern:only;"); + goto end; + } + if (str[0] != '-' && isalpha((unsigned char)str[0])) { + SigMatch *bed_sm = DetectByteExtractRetrieveSMVar(str, s); + if (bed_sm == NULL) { + SCLogError(SC_ERR_INVALID_SIGNATURE, "unknown byte_extract var " + "seen in distance - %s\n", str); + goto end; + } + cd->distance = ((DetectByteExtractData *)bed_sm->ctx)->local_id; + cd->flags |= DETECT_CONTENT_DISTANCE_BE; + } else { + cd->distance = strtol(str, NULL, 10); + } + cd->flags |= DETECT_CONTENT_DISTANCE; + + SigMatch *prev_pm = SigMatchGetLastSMFromLists(s, 4, + DETECT_CONTENT, pm->prev, + DETECT_PCRE, pm->prev); + if (prev_pm == NULL) { + ret = 0; + goto end; + } + if (prev_pm->type == DETECT_CONTENT) { + DetectContentData *cd = (DetectContentData *)prev_pm->ctx; + if (cd->flags & DETECT_CONTENT_FAST_PATTERN_ONLY) { + SCLogError(SC_ERR_INVALID_SIGNATURE, "previous keyword " + "has a fast_pattern:only; set. Can't " + "have relative keywords around a fast_pattern " + "only content"); + goto end; + } + cd->flags |= DETECT_CONTENT_RELATIVE_NEXT; + } else if (prev_pm->type == DETECT_PCRE) { + DetectPcreData *pd = (DetectPcreData *)prev_pm->ctx; + pd->flags |= DETECT_PCRE_RELATIVE_NEXT; + } + + ret = 0; + end: + if (dubbed) + SCFree(str); + return ret; +} + +#ifdef UNITTESTS + +static int DetectDistanceTest01(void) +{ + int result = 0; + + DetectEngineCtx *de_ctx = DetectEngineCtxInit(); + if (de_ctx == NULL) { + printf("no de_ctx: "); + goto end; + } + + de_ctx->mpm_matcher = MPM_B2G; + de_ctx->flags |= DE_QUIET; + + de_ctx->sig_list = SigInit(de_ctx, "alert tcp any any -> any any (content:\"|AA BB|\"; content:\"|CC DD EE FF 00 11 22 33 44 55 66 77 88 99 AA BB CC DD EE|\"; distance: 4; within: 19; sid:1; rev:1;)"); + if (de_ctx->sig_list == NULL) { + printf("sig parse failed: "); + goto end; + } + + SigMatch *sm = de_ctx->sig_list->sm_lists[DETECT_SM_LIST_PMATCH]; + if (sm == NULL) { + printf("sm NULL: "); + goto end; + } + + sm = sm->next; + if (sm == NULL) { + printf("sm2 NULL: "); + goto end; + } + + DetectContentData *co = (DetectContentData *)sm->ctx; + if (co == NULL) { + printf("co == NULL: "); + goto end; + } + + if (co->distance != 4) { + printf("distance %"PRIi32", expected 4: ", co->distance); + goto end; + } + + /* within needs to be 23: distance + content_len as Snort auto fixes this */ + if (co->within != 19) { + printf("within %"PRIi32", expected 23: ", co->within); + goto end; + } + + result = 1; +end: + DetectEngineCtxFree(de_ctx); + return result; +} + +/** + * \test DetectDistanceTestPacket01 is a test to check matches of + * distance works, if the previous keyword is byte_jump and content + * (bug 163) + */ +int DetectDistanceTestPacket01 (void) +{ + int result = 0; + uint8_t buf[] = { 0x01, 0x00, 0x00, 0x00, 0x00, 0x00 }; + uint16_t buflen = sizeof(buf); + Packet *p; + p = UTHBuildPacket((uint8_t *)buf, buflen, IPPROTO_TCP); + + if (p == NULL) + goto end; + + char sig[] = "alert tcp any any -> any any (msg:\"suricata test\"; " + "byte_jump:1,2; content:\"|00|\"; " + "within:1; distance:2; sid:98711212; rev:1;)"; + + p->flowflags = FLOW_PKT_ESTABLISHED | FLOW_PKT_TOCLIENT; + result = UTHPacketMatchSig(p, sig); + + UTHFreePacket(p); +end: + return result; +} +#endif /* UNITTESTS */ + +void DetectDistanceRegisterTests(void) +{ +#ifdef UNITTESTS + UtRegisterTest("DetectDistanceTest01 -- distance / within mix", DetectDistanceTest01, 1); + UtRegisterTest("DetectDistanceTestPacket01", DetectDistanceTestPacket01, 1); +#endif /* UNITTESTS */ +} + |