added pmsnare parser module

Signed-off-by: Rainer Gerhards <rgerhards@adiscon.com>

1 files changed, 233 insertions, 0 deletions

diff --git a/plugins/pmsnare/pmsnare.c b/plugins/pmsnare/pmsnare.c
new file mode 100644
index 00000000..ce2138b2
--- /dev/null
+++ b/plugins/pmsnare/pmsnare.c
@@ -0,0 +1,233 @@
+/* pmsnare.c
+ *
+ * this detects logs sent by Snare and cleans them up so that they can be processed by the normal parser
+ *
+ * there are two variations of this, if the client is set to 'syslog' mode it sends
+ *
+ * <pri>timestamp<sp>hostname<sp>tag<tab>otherstuff
+ *
+ * if the client is not set to syslog it sends
+ *
+ * hostname<tab>tag<tab>otherstuff
+ *
+ * ToDo, take advantage of items in the message itself to set more friendly information
+ * where the normal parser will find it by re-writing more of the message
+ *
+ * Intereting information includes:
+ *
+ * in the case of windows snare messages:
+ *   the system hostname is field 12
+ *   the severity is field 3 (criticality ranging form 0 to 4)
+ *   the source of the log is field 4 and may be able to be mapped to facility
+ * 
+ * 
+ * created 2010-12-13 by David Lang based on pmlastmsg
+ *
+ * This file is part of rsyslog.
+ *
+ * Rsyslog is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Rsyslog 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
+ * along with Rsyslog.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * A copy of the GPL can be found in the file "COPYING" in this distribution.
+ */
+#include "config.h"
+#include "rsyslog.h"
+#include <stdlib.h>
+#include <string.h>
+#include <assert.h>
+#include <ctype.h>
+#include "conf.h"
+#include "syslogd-types.h"
+#include "template.h"
+#include "msg.h"
+#include "module-template.h"
+#include "glbl.h"
+#include "errmsg.h"
+#include "parser.h"
+#include "datetime.h"
+#include "unicode-helper.h"
+
+MODULE_TYPE_PARSER
+PARSER_NAME("rsyslog.snare")
+
+/* internal structures
+ */
+DEF_PMOD_STATIC_DATA
+DEFobjCurrIf(errmsg)
+DEFobjCurrIf(glbl)
+DEFobjCurrIf(parser)
+DEFobjCurrIf(datetime)
+
+
+/* static data */
+static int bParseHOSTNAMEandTAG;	/* cache for the equally-named global param - performance enhancement */
+
+
+BEGINisCompatibleWithFeature
+CODESTARTisCompatibleWithFeature
+	if(eFeat == sFEATUREAutomaticSanitazion)
+		iRet = RS_RET_OK;
+	if(eFeat == sFEATUREAutomaticPRIParsing)
+		iRet = RS_RET_OK;
+ENDisCompatibleWithFeature
+
+
+BEGINparse
+	uchar *p2parse;
+	int lenMsg;
+	int snaremessage;
+	int tablength;
+
+CODESTARTparse
+	#define TabRepresentation "#011"
+	tablength=sizeof(TabRepresentation);
+	dbgprintf("Message will now be parsed by fix Snare parser.\n");
+	assert(pMsg != NULL);
+	assert(pMsg->pszRawMsg != NULL);
+
+	/* check if this message is of the type we handle in this (very limited) parser
+
+	 find out if we have a space separated or tab separated for the first item
+	 if tab separated see if the second word is one of our expected tags
+	  if so replace the tabs with spaces so that hostname and syslog tag are going to be parsed properly
+	   optionally replace the hostname at the beginning of the message with one from later in the message
+	  else, wrong message, abort
+	 else, assume that we have a valid timestamp, move over to the syslog tag
+	  if that is tab separated from the rest of the message and one of our expected tags
+	   if so, replace the tab with a space so that it will be parsed properly
+	    optionally replace the hostname at the beginning of the message withone from later in the message 
+
+	*/
+	snaremessage=0;
+	lenMsg = pMsg->iLenRawMsg - pMsg->offAfterPRI; /* note: offAfterPRI is already the number of PRI chars (do not add one!) */
+	p2parse = pMsg->pszRawMsg + pMsg->offAfterPRI; /* point to start of text, after PRI */
+	dbgprintf("pmsnare: msg to look at: [%d]'%s'\n", lenMsg, p2parse);
+	if((unsigned) lenMsg < 30) {
+		/* too short, can not be "our" message */
+		dbgprintf("msg too short!\n");
+		ABORT_FINALIZE(RS_RET_COULD_NOT_PARSE);
+	}
+
+	while(lenMsg && *p2parse != ' ' && *p2parse != '\t' && *p2parse != '#') {
+		--lenMsg;
+		++p2parse;
+	}
+	dbgprintf("pmsnare: separator [%d]'%s'  msg after the first separator: [%d]'%s'\n", tablength,TabRepresentation,lenMsg, p2parse);
+	if ((lenMsg > tablength) && (*p2parse == '\t' || strncasecmp((char*) p2parse, TabRepresentation , tablength-1) == 0)) {
+	//if ((lenMsg > tablength) && (*p2parse == '\t' || *p2parse == '#')) {
+	dbgprintf("pmsnare: tab separated message\n");
+		if(strncasecmp((char*) (p2parse + tablength - 1), "MSWinEventLog", 13) == 0) {
+			snaremessage=13; /* 0 means not a snare message, a number is how long the tag is */
+		}
+		if(strncasecmp((char*) (p2parse + tablength - 1), "LinuxKAudit", 11) == 0) {
+			snaremessage=11; /* 0 means not a snare message, a number is how long the tag is */
+		}
+		if(snaremessage) {
+			/* replace the tab with a space and if needed move the message portion up by the length of TabRepresentation -2 characters to overwrite the extra : */
+			*p2parse = ' ';
+			lenMsg -=(tablength-2);
+			p2parse++;
+			memmove(p2parse, p2parse + (tablength-2), lenMsg);
+			*(p2parse + lenMsg) = '\n';
+			*(p2parse + lenMsg + 1)  = '\0';
+			pMsg->iLenRawMsg -=(tablength-2);
+			pMsg->iLenMSG -=(tablength-2);
+			p2parse += snaremessage;
+			*p2parse = ' ';
+			p2parse++;
+			lenMsg -=(tablength-2);
+			memmove(p2parse, p2parse + (tablength-2), lenMsg);
+			*(p2parse + lenMsg) = '\n';
+			*(p2parse + lenMsg + 1)  = '\0';
+			pMsg->iLenRawMsg -=(tablength-2);
+			pMsg->iLenMSG -=(tablength-2);
+			dbgprintf("found a Snare message with snare not set to send syslog messages\n");
+		}
+	} else {
+		/* go back to the beginning of the message */
+		lenMsg = pMsg->iLenRawMsg - pMsg->offAfterPRI; /* note: offAfterPRI is already the number of PRI chars (do not add one!) */
+		p2parse = pMsg->pszRawMsg + pMsg->offAfterPRI; /* point to start of text, after PRI */
+		/* skip over timestamp and space*/
+		lenMsg -=17;
+		p2parse +=17;
+		/* skip over what should be the hostname */
+		while(lenMsg && *p2parse != ' ') {
+			--lenMsg;
+			++p2parse;
+		}
+		if (lenMsg){
+			--lenMsg;
+			++p2parse;
+		}
+		dbgprintf("pmsnare: separator [%d]'%s'  msg after the timestamp and hostname: [%d]'%s'\n", tablength,TabRepresentation,lenMsg, p2parse);
+		if(lenMsg > 13 && strncasecmp((char*) p2parse, "MSWinEventLog", 13) == 0) {
+			snaremessage=13; /* 0 means not a snare message, a number is how long the tag is */
+		}
+		if(lenMsg > 11 && strncasecmp((char*) p2parse, "LinuxKAudit", 11) == 0) {
+			snaremessage=11; /* 0 means not a snare message, a number is how long the tag is */
+		}
+		if(snaremessage) {
+			p2parse += snaremessage;
+			*p2parse = ' ';
+			p2parse++;
+			lenMsg -=(tablength-2);
+			memmove(p2parse, p2parse + (tablength-2), lenMsg);
+			*(p2parse + lenMsg) = '\n';
+			*(p2parse + lenMsg + 1)  = '\0';
+			pMsg->iLenRawMsg -=(tablength-2);
+			pMsg->iLenMSG -=(tablength-2);
+			dbgprintf("found a Snare message with snare set to send syslog messages\n");
+		}
+		
+	}
+	DBGPRINTF("pmsnare: new mesage: [%d]'%s'\n", lenMsg, pMsg->pszRawMsg + pMsg->offAfterPRI);
+	ABORT_FINALIZE(RS_RET_COULD_NOT_PARSE);
+
+finalize_it:
+ENDparse
+
+
+BEGINmodExit
+CODESTARTmodExit
+	/* release what we no longer need */
+	objRelease(errmsg, CORE_COMPONENT);
+	objRelease(glbl, CORE_COMPONENT);
+	objRelease(parser, CORE_COMPONENT);
+	objRelease(datetime, CORE_COMPONENT);
+ENDmodExit
+
+
+BEGINqueryEtryPt
+CODESTARTqueryEtryPt
+CODEqueryEtryPt_STD_PMOD_QUERIES
+CODEqueryEtryPt_IsCompatibleWithFeature_IF_OMOD_QUERIES
+ENDqueryEtryPt
+
+
+BEGINmodInit()
+CODESTARTmodInit
+	*ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
+CODEmodInit_QueryRegCFSLineHdlr
+	CHKiRet(objUse(glbl, CORE_COMPONENT));
+	CHKiRet(objUse(errmsg, CORE_COMPONENT));
+	CHKiRet(objUse(parser, CORE_COMPONENT));
+	CHKiRet(objUse(datetime, CORE_COMPONENT));
+
+	DBGPRINTF("snare parser init called, compiled with version %s\n", VERSION);
+ 	bParseHOSTNAMEandTAG = glbl.GetParseHOSTNAMEandTAG(); /* cache value, is set only during rsyslogd option processing */
+
+
+ENDmodInit
+
+/* vim:set ai:
+ */