/** * \brief this function is used to parse filedata 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 "filestore" option * * \retval 0 on Success * \retval -1 on Failure */ static int DetectFiledataSetup (DetectEngineCtx *de_ctx, Signature *s, char *str) { SCEnter(); if (!DetectProtoContainsProto(&s->proto, IPPROTO_TCP) && s->alproto != ALPROTO_UNKNOWN && s->alproto != ALPROTO_HTTP && s->alproto != ALPROTO_SMTP) { SCLogError(SC_ERR_CONFLICTING_RULE_KEYWORDS, "rule contains conflicting keywords."); return -1; } if (s->alproto == ALPROTO_HTTP && (s->init_flags & SIG_FLAG_INIT_FLOW) && (s->flags & SIG_FLAG_TOSERVER) && !(s->flags & SIG_FLAG_TOCLIENT)) { SCLogError(SC_ERR_INVALID_SIGNATURE, "Can't use file_data with flow:to_server or from_client with http."); return -1; } if (s->alproto == ALPROTO_SMTP && (s->init_flags & SIG_FLAG_INIT_FLOW) && !(s->flags & SIG_FLAG_TOSERVER) && (s->flags & SIG_FLAG_TOCLIENT)) { SCLogError(SC_ERR_INVALID_SIGNATURE, "Can't use file_data with flow:to_client or from_server with smtp."); return -1; } s->list = DETECT_SM_LIST_FILEDATA; return 0; }
/** * \brief Prints analysis of loaded rules. * * Warns if potential rule issues are detected. For example, * warns if a rule uses a construct that may perform poorly, * e.g. pcre without content or with http_method content only; * warns if a rule uses a construct that may not be consistent with intent, * e.g. client side ports only, http and content without any http_* modifiers, etc. * * \param s Pointer to the signature. */ void EngineAnalysisRules(Signature *s, char *line) { uint32_t rule_bidirectional = 0; uint32_t rule_pcre = 0; uint32_t rule_pcre_http = 0; uint32_t rule_content = 0; uint32_t rule_flow = 0; uint32_t rule_flags = 0; uint32_t rule_flow_toserver = 0; uint32_t rule_flow_toclient = 0; uint32_t rule_flow_nostream = 0; uint32_t rule_ipv4_only = 0; uint32_t rule_ipv6_only = 0; uint32_t rule_flowbits = 0; uint32_t rule_flowint = 0; //uint32_t rule_flowvar = 0; uint32_t rule_content_http = 0; uint32_t rule_content_offset_depth = 0; uint32_t list_id = 0; uint32_t rule_warning = 0; uint32_t raw_http_buf = 0; uint32_t norm_http_buf = 0; uint32_t stream_buf = 0; uint32_t packet_buf = 0; uint32_t http_header_buf = 0; uint32_t http_uri_buf = 0; uint32_t http_method_buf = 0; uint32_t http_cookie_buf = 0; uint32_t http_client_body_buf = 0; uint32_t http_server_body_buf = 0; uint32_t http_stat_code_buf = 0; uint32_t http_stat_msg_buf = 0; uint32_t http_raw_header_buf = 0; uint32_t http_raw_uri_buf = 0; uint32_t http_ua_buf = 0; uint32_t warn_pcre_no_content = 0; uint32_t warn_pcre_http_content = 0; uint32_t warn_pcre_http = 0; uint32_t warn_content_http_content = 0; uint32_t warn_content_http = 0; uint32_t warn_tcp_no_flow = 0; uint32_t warn_client_ports = 0; uint32_t warn_direction = 0; uint32_t warn_method_toclient = 0; uint32_t warn_method_serverbody = 0; uint32_t warn_pcre_method = 0; uint32_t warn_encoding_norm_http_buf = 0; uint32_t warn_offset_depth_pkt_stream = 0; uint32_t warn_offset_depth_alproto = 0; uint32_t warn_non_alproto_fp_for_alproto_sig = 0; if (s->init_flags & SIG_FLAG_INIT_BIDIREC) { rule_bidirectional = 1; } if (s->flags & SIG_FLAG_REQUIRE_PACKET) { packet_buf += 1; } if (s->flags & SIG_FLAG_REQUIRE_STREAM) { stream_buf += 1; } if (s->proto.flags & DETECT_PROTO_IPV4) { rule_ipv4_only += 1; } if (s->proto.flags & DETECT_PROTO_IPV6) { rule_ipv6_only += 1; } for (list_id = 0; list_id < DETECT_SM_LIST_MAX; list_id++) { SigMatch *sm = NULL; for (sm = s->sm_lists[list_id]; sm != NULL; sm = sm->next) { if (sm->type == DETECT_PCRE) { if (list_id == DETECT_SM_LIST_HCBDMATCH) { rule_pcre_http += 1; http_client_body_buf += 1; raw_http_buf += 1; } else if (list_id == DETECT_SM_LIST_UMATCH) { rule_pcre_http += 1; norm_http_buf += 1; http_uri_buf += 1; } else if (list_id == DETECT_SM_LIST_HHDMATCH) { rule_pcre_http += 1; norm_http_buf += 1; http_header_buf += 1; } else if (list_id == DETECT_SM_LIST_HCDMATCH) { rule_pcre_http += 1; norm_http_buf += 1; http_cookie_buf += 1; } else if (list_id == DETECT_SM_LIST_HSBDMATCH) { rule_pcre_http += 1; http_server_body_buf += 1; raw_http_buf += 1; } else if (list_id == DETECT_SM_LIST_HRHDMATCH) { rule_pcre_http += 1; raw_http_buf += 1; http_raw_header_buf += 1; } else if (list_id == DETECT_SM_LIST_HMDMATCH) { rule_pcre_http += 1; raw_http_buf += 1; http_method_buf += 1; } else if (list_id == DETECT_SM_LIST_HRUDMATCH) { rule_pcre_http += 1; raw_http_buf += 1; http_raw_uri_buf += 1; } else if (list_id == DETECT_SM_LIST_HSMDMATCH) { rule_pcre_http += 1; raw_http_buf += 1; http_stat_msg_buf += 1; } else if (list_id == DETECT_SM_LIST_HSCDMATCH) { rule_pcre_http += 1; raw_http_buf += 1; http_stat_code_buf += 1; } else if (list_id == DETECT_SM_LIST_HUADMATCH) { rule_pcre_http += 1; norm_http_buf += 1; http_ua_buf += 1; } else { rule_pcre += 1; } } else if (sm->type == DETECT_CONTENT) { if (list_id == DETECT_SM_LIST_UMATCH || list_id == DETECT_SM_LIST_HHDMATCH || list_id == DETECT_SM_LIST_HCDMATCH) { rule_content_http += 1; norm_http_buf += 1; DetectContentData *cd = (DetectContentData *)sm->ctx; if (cd != NULL && PerCentEncodingMatch(cd->content, cd->content_len) > 0) { warn_encoding_norm_http_buf += 1; rule_warning += 1; } if (list_id == DETECT_SM_LIST_UMATCH) { http_uri_buf += 1; } else if (list_id == DETECT_SM_LIST_HHDMATCH) { http_header_buf += 1; } else if (list_id == DETECT_SM_LIST_HCDMATCH) { http_cookie_buf += 1; } } else if (list_id == DETECT_SM_LIST_HCBDMATCH) { rule_content_http += 1; raw_http_buf += 1; http_client_body_buf += 1; } else if (list_id == DETECT_SM_LIST_HSBDMATCH) { rule_content_http += 1; raw_http_buf += 1; http_server_body_buf += 1; } else if (list_id == DETECT_SM_LIST_HRHDMATCH) { rule_content_http += 1; raw_http_buf += 1; http_raw_header_buf += 1; } else if (list_id == DETECT_SM_LIST_HRUDMATCH) { rule_content_http += 1; raw_http_buf += 1; http_raw_uri_buf += 1; } else if (list_id == DETECT_SM_LIST_HSMDMATCH) { rule_content_http += 1; raw_http_buf += 1; http_stat_msg_buf += 1; } else if (list_id == DETECT_SM_LIST_HSCDMATCH) { rule_content_http += 1; raw_http_buf += 1; http_stat_code_buf += 1; } else if (list_id == DETECT_SM_LIST_HMDMATCH) { rule_content_http += 1; raw_http_buf += 1; http_method_buf += 1; } else if (list_id == DETECT_SM_LIST_PMATCH) { rule_content += 1; DetectContentData *cd = (DetectContentData *)sm->ctx; if (cd->flags & (DETECT_CONTENT_OFFSET | DETECT_CONTENT_DEPTH)) { rule_content_offset_depth++; } } } else if (sm->type == DETECT_FLOW) { rule_flow += 1; if ((s->flags & SIG_FLAG_TOSERVER) && !(s->flags & SIG_FLAG_TOCLIENT)) { rule_flow_toserver = 1; } else if ((s->flags & SIG_FLAG_TOCLIENT) && !(s->flags & SIG_FLAG_TOSERVER)) { rule_flow_toclient = 1; } DetectFlowData *fd = (DetectFlowData *)sm->ctx; if (fd != NULL) { if (fd->flags & FLOW_PKT_NOSTREAM) rule_flow_nostream = 1; } } else if (sm->type == DETECT_FLOWBITS) { if (list_id == DETECT_SM_LIST_MATCH) { rule_flowbits += 1; } } else if (sm->type == DETECT_FLOWINT) { if (list_id == DETECT_SM_LIST_MATCH) { rule_flowint += 1; } } else if (sm->type == DETECT_FLAGS) { DetectFlagsData *fd = (DetectFlagsData *)sm->ctx; if (fd != NULL) { rule_flags = 1; } } } /* for (sm = s->sm_lists[list_id]; sm != NULL; sm = sm->next) */ } /* for ( ; list_id < DETECT_SM_LIST_MAX; list_id++) */ if (rule_pcre > 0 && rule_content == 0 && rule_content_http == 0) { rule_warning += 1; warn_pcre_no_content = 1; } if (rule_content_http > 0 && rule_pcre > 0 && rule_pcre_http == 0) { rule_warning += 1; warn_pcre_http_content = 1; } else if (s->alproto == ALPROTO_HTTP && rule_pcre > 0 && rule_pcre_http == 0) { rule_warning += 1; warn_pcre_http = 1; } if (rule_content > 0 && rule_content_http > 0) { rule_warning += 1; warn_content_http_content = 1; } if (s->alproto == ALPROTO_HTTP && rule_content > 0 && rule_content_http == 0) { rule_warning += 1; warn_content_http = 1; } if (rule_content == 1) { //todo: warning if content is weak, separate warning for pcre + weak content } if (rule_flow == 0 && rule_flags == 0 && !(s->proto.flags & DETECT_PROTO_ANY) && DetectProtoContainsProto(&s->proto, IPPROTO_TCP) && (rule_content || rule_content_http || rule_pcre || rule_pcre_http || rule_flowbits)) { rule_warning += 1; warn_tcp_no_flow = 1; } if (rule_flow && !rule_bidirectional && (rule_flow_toserver || rule_flow_toclient) && !((s->flags & SIG_FLAG_SP_ANY) && (s->flags & SIG_FLAG_DP_ANY))) { if (((s->flags & SIG_FLAG_TOSERVER) && !(s->flags & SIG_FLAG_SP_ANY) && (s->flags & SIG_FLAG_DP_ANY)) || ((s->flags & SIG_FLAG_TOCLIENT) && !(s->flags & SIG_FLAG_DP_ANY) && (s->flags & SIG_FLAG_SP_ANY))) { rule_warning += 1; warn_client_ports = 1; } } if (rule_flow && rule_bidirectional && (rule_flow_toserver || rule_flow_toclient)) { rule_warning += 1; warn_direction = 1; } if (http_method_buf) { if (rule_flow && rule_flow_toclient) { rule_warning += 1; warn_method_toclient = 1; } if (http_server_body_buf) { rule_warning += 1; warn_method_serverbody = 1; } if (rule_content == 0 && rule_content_http == 0 && (rule_pcre > 0 || rule_pcre_http > 0)) { rule_warning += 1; warn_pcre_method = 1; } } if (rule_content_offset_depth > 0 && stream_buf && packet_buf) { rule_warning += 1; warn_offset_depth_pkt_stream = 1; } if (rule_content_offset_depth > 0 && !stream_buf && packet_buf && s->alproto != ALPROTO_UNKNOWN) { rule_warning += 1; warn_offset_depth_alproto = 1; } if (s->mpm_sm != NULL && s->alproto == ALPROTO_HTTP && SigMatchListSMBelongsTo(s, s->mpm_sm) == DETECT_SM_LIST_PMATCH) { rule_warning += 1; warn_non_alproto_fp_for_alproto_sig = 1; } if (!rule_warnings_only || (rule_warnings_only && rule_warning > 0)) { fprintf(rule_engine_analysis_FD, "== Sid: %u ==\n", s->id); fprintf(rule_engine_analysis_FD, "%s\n", line); if (s->flags & SIG_FLAG_IPONLY) fprintf(rule_engine_analysis_FD, " Rule is ip only.\n"); if (rule_ipv6_only) fprintf(rule_engine_analysis_FD, " Rule is IPv6 only.\n"); if (rule_ipv4_only) fprintf(rule_engine_analysis_FD, " Rule is IPv4 only.\n"); if (packet_buf) fprintf(rule_engine_analysis_FD, " Rule matches on packets.\n"); if (!rule_flow_nostream && stream_buf && (rule_flow || rule_flowbits || rule_content || rule_pcre)) { fprintf(rule_engine_analysis_FD, " Rule matches on reassembled stream.\n"); } if (http_uri_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http uri buffer.\n"); if (http_header_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http header buffer.\n"); if (http_cookie_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http cookie buffer.\n"); if (http_raw_uri_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http raw uri buffer.\n"); if (http_raw_header_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http raw header buffer.\n"); if (http_method_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http method buffer.\n"); if (http_server_body_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http server body buffer.\n"); if (http_client_body_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http client body buffer.\n"); if (http_stat_msg_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http stat msg buffer.\n"); if (http_stat_code_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http stat code buffer.\n"); if (http_ua_buf) fprintf(rule_engine_analysis_FD, " Rule matches on http user agent buffer.\n"); if (s->alproto != ALPROTO_UNKNOWN) { fprintf(rule_engine_analysis_FD, " App layer protocol is %s.\n", AppProtoToString(s->alproto)); } if (rule_content || rule_content_http || rule_pcre || rule_pcre_http) { fprintf(rule_engine_analysis_FD, " Rule contains %d content options, %d http content options, %d pcre options, and %d pcre options with http modifiers.\n", rule_content, rule_content_http, rule_pcre, rule_pcre_http); } /* print fast pattern info */ EngineAnalysisRulesPrintFP(s); /* this is where the warnings start */ if (warn_pcre_no_content /*rule_pcre > 0 && rule_content == 0 && rule_content_http == 0*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule uses pcre without a content option present.\n" " -Consider adding a content to improve performance of this rule.\n"); } if (warn_pcre_http_content /*rule_content_http > 0 && rule_pcre > 0 && rule_pcre_http == 0*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule uses content options with http_* and pcre options without http modifiers.\n" " -Consider adding http pcre modifier.\n"); } else if (warn_pcre_http /*s->alproto == ALPROTO_HTTP && rule_pcre > 0 && rule_pcre_http == 0*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule app layer protocol is http, but pcre options do not have http modifiers.\n" " -Consider adding http pcre modifiers.\n"); } if (warn_content_http_content /*rule_content > 0 && rule_content_http > 0*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule contains content with http_* and content without http_*.\n" " -Consider adding http content modifiers.\n"); } if (warn_content_http /*s->alproto == ALPROTO_HTTP && rule_content > 0 && rule_content_http == 0*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule app layer protocol is http, but content options do not have http_* modifiers.\n" " -Consider adding http content modifiers.\n"); } if (rule_content == 1) { //todo: warning if content is weak, separate warning for pcre + weak content } if (warn_encoding_norm_http_buf) { fprintf(rule_engine_analysis_FD, " Warning: Rule may contain percent encoded content for a normalized http buffer match.\n"); } if (warn_tcp_no_flow /*rule_flow == 0 && rule_flow == 0 && !(s->proto.flags & DETECT_PROTO_ANY) && DetectProtoContainsProto(&s->proto, IPPROTO_TCP)*/) { fprintf(rule_engine_analysis_FD, " Warning: TCP rule without a flow or flags option.\n" " -Consider adding flow or flags to improve performance of this rule.\n"); } if (warn_client_ports /*rule_flow && !rule_bidirectional && (rule_flow_toserver || rule_flow_toclient) && !((s->flags & SIG_FLAG_SP_ANY) && (s->flags & SIG_FLAG_DP_ANY))) if (((s->flags & SIG_FLAG_TOSERVER) && !(s->flags & SIG_FLAG_SP_ANY) && (s->flags & SIG_FLAG_DP_ANY)) || ((s->flags & SIG_FLAG_TOCLIENT) && !(s->flags & SIG_FLAG_DP_ANY) && (s->flags & SIG_FLAG_SP_ANY))*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule contains ports or port variables only on the client side.\n" " -Flow direction possibly inconsistent with rule.\n"); } if (warn_direction /*rule_flow && rule_bidirectional && (rule_flow_toserver || rule_flow_toclient)*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule is bidirectional and has a flow option with a specific direction.\n"); } if (warn_method_toclient /*http_method_buf && rule_flow && rule_flow_toclient*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule uses content or pcre for http_method with flow:to_client or from_server\n"); } if (warn_method_serverbody /*http_method_buf && http_server_body_buf*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule uses content or pcre for http_method with content or pcre for http_server_body.\n"); } if (warn_pcre_method /*http_method_buf && rule_content == 0 && rule_content_http == 0 && (rule_pcre > 0 || rule_pcre_http > 0)*/) { fprintf(rule_engine_analysis_FD, " Warning: Rule uses pcre with only a http_method content; possible performance issue.\n"); } if (warn_offset_depth_pkt_stream) { fprintf(rule_engine_analysis_FD, " Warning: Rule has depth" "/offset with raw content keywords. Please note the " "offset/depth will be checked against both packet " "payloads and stream. If you meant to have the offset/" "depth checked against just the payload, you can update " "the signature as \"alert tcp-pkt...\"\n"); } if (warn_offset_depth_alproto) { fprintf(rule_engine_analysis_FD, " Warning: Rule has " "offset/depth set along with a match on a specific " "app layer protocol - %d. This can lead to FNs if we " "have a offset/depth content match on a packet payload " "before we can detect the app layer protocol for the " "flow.\n", s->alproto); } if (warn_non_alproto_fp_for_alproto_sig) { fprintf(rule_engine_analysis_FD, " Warning: Rule app layer " "protocol is http, but the fast_pattern is set on the raw " "stream. Consider adding fast_pattern over a http " "buffer for increased performance."); } if (rule_warning == 0) { fprintf(rule_engine_analysis_FD, " No warnings for this rule.\n"); } fprintf(rule_engine_analysis_FD, "\n"); } return; }