/* parser.c * This module contains functions for message parsers. It still needs to be * converted into an object (and much extended). * * Module begun 2008-10-09 by Rainer Gerhards (based on previous code from syslogd.c) * * Copyright 2008 Rainer Gerhards and Adiscon GmbH. * * This file is part of the rsyslog runtime library. * * The rsyslog runtime library is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * The rsyslog runtime library 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with the rsyslog runtime library. If not, see . * * A copy of the GPL can be found in the file "COPYING" in this distribution. * A copy of the LGPL can be found in the file "COPYING.LESSER" in this distribution. */ #include "config.h" #include #include #include #include #ifdef USE_NETZIP #include #endif #include "rsyslog.h" #include "dirty.h" #include "msg.h" #include "obj.h" #include "datetime.h" #include "errmsg.h" #include "parser.h" #include "ruleset.h" #include "unicode-helper.h" #include "dirty.h" #include "cfsysline.h" /* some defines */ #define DEFUPRI (LOG_USER|LOG_NOTICE) /* definitions for objects we access */ DEFobjStaticHelpers DEFobjCurrIf(glbl) DEFobjCurrIf(errmsg) DEFobjCurrIf(datetime) DEFobjCurrIf(ruleset) /* static data */ /* config data */ static uchar cCCEscapeChar = '#';/* character to be used to start an escape sequence for control chars */ static int bEscapeCCOnRcv = 1; /* escape control characters on reception: 0 - no, 1 - yes */ static int bEscape8BitChars = 0; /* escape characters > 127 on reception: 0 - no, 1 - yes */ static int bEscapeTab = 1; /* escape tab control character when doing CC escapes: 0 - no, 1 - yes */ static int bDropTrailingLF = 1; /* drop trailing LF's on reception? */ /* This is the list of all parsers known to us. * This is also used to unload all modules on shutdown. */ parserList_t *pParsLstRoot = NULL; /* this is the list of the default parsers, to be used if no others * are specified. */ parserList_t *pDfltParsLst = NULL; /* intialize (but NOT allocate) a parser list. Primarily meant as a hook * which can be used to extend the list in the future. So far, just sets * it to NULL. */ static rsRetVal InitParserList(parserList_t **pListRoot) { *pListRoot = NULL; return RS_RET_OK; } /* destruct a parser list. The list elements are destroyed, but the parser objects * themselves are not modified. (That is done at a late stage during rsyslogd * shutdown and need not be considered here.) */ static rsRetVal DestructParserList(parserList_t **ppListRoot) { parserList_t *pParsLst; parserList_t *pParsLstDel; pParsLst = *ppListRoot; while(pParsLst != NULL) { pParsLstDel = pParsLst; pParsLst = pParsLst->pNext; free(pParsLstDel); } *ppListRoot = NULL; return RS_RET_OK; } /* Add a parser to the list. We use a VERY simple and ineffcient algorithm, * but it is employed only for a few milliseconds during config processing. So * I prefer to keep it very simple and with simple data structures. Unfortunately, * we need to preserve the order, but I don't like to add a tail pointer as that * would require a container object. So I do the extra work to skip to the tail * when adding elements... * rgerhards, 2009-11-03 */ static rsRetVal AddParserToList(parserList_t **ppListRoot, parser_t *pParser) { parserList_t *pThis; parserList_t *pTail; DEFiRet; CHKmalloc(pThis = MALLOC(sizeof(parserList_t))); pThis->pParser = pParser; pThis->pNext = NULL; if(*ppListRoot == NULL) { pThis->pNext = *ppListRoot; *ppListRoot = pThis; } else { /* find tail first */ for(pTail = *ppListRoot ; pTail->pNext != NULL ; pTail = pTail->pNext) /* just search, do nothing else */; /* add at tail */ pTail->pNext = pThis; } finalize_it: RETiRet; } /* find a parser based on the provided name */ static rsRetVal FindParser(parser_t **ppParser, uchar *pName) { parserList_t *pThis; DEFiRet; for(pThis = pParsLstRoot ; pThis != NULL ; pThis = pThis->pNext) { if(ustrcmp(pThis->pParser->pName, pName) == 0) { *ppParser = pThis->pParser; FINALIZE; /* found it, iRet still eq. OK! */ } } iRet = RS_RET_PARSER_NOT_FOUND; finalize_it: RETiRet; } /* --- END helper functions for parser list handling --- */ /* Add a an already existing parser to the default list. As usual, order * of calls is important (most importantly, that means the legacy parser, * which can process everything, MUST be added last!). * rgerhards, 2009-11-04 */ static rsRetVal AddDfltParser(uchar *pName) { parser_t *pParser; DEFiRet; CHKiRet(FindParser(&pParser, pName)); CHKiRet(AddParserToList(&pDfltParsLst, pParser)); dbgprintf("Parser '%s' added to default parser set.\n", pName); finalize_it: RETiRet; } BEGINobjConstruct(parser) /* be sure to specify the object type also in END macro! */ ENDobjConstruct(parser) /* ConstructionFinalizer. The most important chore is to add the parser object * to our global list of available parsers. * rgerhards, 2009-11-03 */ rsRetVal parserConstructFinalize(parser_t *pThis) { DEFiRet; ISOBJ_TYPE_assert(pThis, parser); CHKiRet(AddParserToList(&pParsLstRoot, pThis)); DBGPRINTF("Parser '%s' added to list of available parsers.\n", pThis->pName); finalize_it: RETiRet; } BEGINobjDestruct(parser) /* be sure to specify the object type also in END and CODESTART macros! */ CODESTARTobjDestruct(parser) dbgprintf("destructing parser '%s'\n", pThis->pName); free(pThis->pName); ENDobjDestruct(parser) /* uncompress a received message if it is compressed. * pMsg->pszRawMsg buffer is updated. * rgerhards, 2008-10-09 */ static inline rsRetVal uncompressMessage(msg_t *pMsg) { DEFiRet; # ifdef USE_NETZIP uchar *deflateBuf = NULL; uLongf iLenDefBuf; uchar *pszMsg; size_t lenMsg; assert(pMsg != NULL); pszMsg = pMsg->pszRawMsg; lenMsg = pMsg->iLenRawMsg; /* we first need to check if we have a compressed record. If so, * we must decompress it. */ if(lenMsg > 0 && *pszMsg == 'z') { /* compressed data present? (do NOT change order if conditions!) */ /* we have compressed data, so let's deflate it. We support a maximum * message size of iMaxLine. If it is larger, an error message is logged * and the message is dropped. We do NOT try to decompress larger messages * as such might be used for denial of service. It might happen to later * builds that such functionality be added as an optional, operator-configurable * feature. */ int ret; iLenDefBuf = glbl.GetMaxLine(); CHKmalloc(deflateBuf = MALLOC(sizeof(uchar) * (iLenDefBuf + 1))); ret = uncompress((uchar *) deflateBuf, &iLenDefBuf, (uchar *) pszMsg+1, lenMsg-1); DBGPRINTF("Compressed message uncompressed with status %d, length: new %ld, old %d.\n", ret, (long) iLenDefBuf, (int) (lenMsg-1)); /* Now check if the uncompression worked. If not, there is not much we can do. In * that case, we log an error message but ignore the message itself. Storing the * compressed text is dangerous, as it contains control characters. So we do * not do this. If someone would like to have a copy, this code here could be * modified to do a hex-dump of the buffer in question. We do not include * this functionality right now. * rgerhards, 2006-12-07 */ if(ret != Z_OK) { errmsg.LogError(0, NO_ERRCODE, "Uncompression of a message failed with return code %d " "- enable debug logging if you need further information. " "Message ignored.", ret); FINALIZE; /* unconditional exit, nothing left to do... */ } MsgSetRawMsg(pMsg, (char*)deflateBuf, iLenDefBuf); } finalize_it: if(deflateBuf != NULL) free(deflateBuf); # else /* ifdef USE_NETZIP */ /* in this case, we still need to check if the message is compressed. If so, we must * tell the user we can not accept it. */ if(pMsg->iLenRawMsg > 0 && *pMsg->pszRawMsg == 'z') { errmsg.LogError(0, NO_ERRCODE, "Received a compressed message, but rsyslogd does not have compression " "support enabled. The message will be ignored."); ABORT_FINALIZE(RS_RET_NO_ZIP); } finalize_it: # endif /* ifdef USE_NETZIP */ RETiRet; } /* sanitize a received message * if a message gets to large during sanitization, it is truncated. This is * as specified in the upcoming syslog RFC series. * rgerhards, 2008-10-09 * We check if we have a NUL character at the very end of the * message. This seems to be a frequent problem with a number of senders. * So I have now decided to drop these NULs. However, if they are intentional, * that may cause us some problems, e.g. with syslog-sign. On the other hand, * current code always has problems with intentional NULs (as it needs to escape * them to prevent problems with the C string libraries), so that does not * really matter. Just to be on the save side, we'll log destruction of such * NULs in the debug log. * rgerhards, 2007-09-14 */ static inline rsRetVal SanitizeMsg(msg_t *pMsg) { DEFiRet; uchar *pszMsg; uchar *pDst; /* destination for copy job */ size_t lenMsg; size_t iSrc; size_t iDst; size_t iMaxLine; size_t maxDest; sbool bUpdatedLen = FALSE; uchar szSanBuf[32*1024]; /* buffer used for sanitizing a string */ assert(pMsg != NULL); assert(pMsg->iLenRawMsg > 0); pszMsg = pMsg->pszRawMsg; lenMsg = pMsg->iLenRawMsg; /* remove NUL character at end of message (see comment in function header) * Note that we do not need to add a NUL character in this case, because it * is already present ;) */ if(pszMsg[lenMsg-1] == '\0') { DBGPRINTF("dropped NUL at very end of message\n"); bUpdatedLen = TRUE; lenMsg--; } /* then we check if we need to drop trailing LFs, which often make * their way into syslog messages unintentionally. In order to remain * compatible to recent IETF developments, we allow the user to * turn on/off this handling. rgerhards, 2007-07-23 */ if(bDropTrailingLF && pszMsg[lenMsg-1] == '\n') { DBGPRINTF("dropped LF at very end of message (DropTrailingLF is set)\n"); lenMsg--; pszMsg[lenMsg] = '\0'; bUpdatedLen = TRUE; } /* it is much quicker to sweep over the message and see if it actually * needs sanitation than to do the sanitation in any case. So we first do * this and terminate when it is not needed - which is expectedly the case * for the vast majority of messages. -- rgerhards, 2009-06-15 * Note that we do NOT check here if tab characters are to be escaped or * not. I expect this functionality to be seldomly used and thus I do not * like to pay the performance penalty. So the penalty is only with those * that actually use it, because we may call the sanitizer without actual * need below (but it then still will work perfectly well!). -- rgerhards, 2009-11-27 */ int bNeedSanitize = 0; for(iSrc = 0 ; iSrc < lenMsg ; iSrc++) { if(iscntrl(pszMsg[iSrc])) { if(pszMsg[iSrc] == '\0' || bEscapeCCOnRcv) { bNeedSanitize = 1; break; } } else if(pszMsg[iSrc] > 127 && bEscape8BitChars) { bNeedSanitize = 1; break; } } if(!bNeedSanitize) { if(bUpdatedLen == TRUE) MsgSetRawMsgSize(pMsg, lenMsg); FINALIZE; } /* now copy over the message and sanitize it */ iMaxLine = glbl.GetMaxLine(); maxDest = lenMsg * 4; /* message can grow at most four-fold */ if(maxDest > iMaxLine) maxDest = iMaxLine; /* but not more than the max size! */ if(maxDest < sizeof(szSanBuf)) pDst = szSanBuf; else CHKmalloc(pDst = MALLOC(sizeof(uchar) * (iMaxLine + 1))); iSrc = iDst = 0; while(iSrc < lenMsg && iDst < maxDest - 3) { /* leave some space if last char must be escaped */ if(iscntrl((int) pszMsg[iSrc]) && (pszMsg[iSrc] != '\t' || bEscapeTab)) { /* note: \0 must always be escaped, the rest of the code currently * can not handle it! -- rgerhards, 2009-08-26 */ if(pszMsg[iSrc] == '\0' || bEscapeCCOnRcv) { /* we are configured to escape control characters. Please note * that this most probably break non-western character sets like * Japanese, Korean or Chinese. rgerhards, 2007-07-17 */ pDst[iDst++] = cCCEscapeChar; pDst[iDst++] = '0' + ((pszMsg[iSrc] & 0300) >> 6); pDst[iDst++] = '0' + ((pszMsg[iSrc] & 0070) >> 3); pDst[iDst++] = '0' + ((pszMsg[iSrc] & 0007)); } } else if(pszMsg[iSrc] > 127 && bEscape8BitChars) { /* In this case, we also do the conversion. Note that this most * probably breaks European languages. -- rgerhards, 2010-01-27 */ pDst[iDst++] = cCCEscapeChar; pDst[iDst++] = '0' + ((pszMsg[iSrc] & 0300) >> 6); pDst[iDst++] = '0' + ((pszMsg[iSrc] & 0070) >> 3); pDst[iDst++] = '0' + ((pszMsg[iSrc] & 0007)); } else { pDst[iDst++] = pszMsg[iSrc]; } ++iSrc; } pDst[iDst] = '\0'; MsgSetRawMsg(pMsg, (char*)pDst, iDst); /* save sanitized string */ if(pDst != szSanBuf) free(pDst); finalize_it: RETiRet; } /* A standard parser to parse out the PRI. This is made available in * this module as it is expected that allmost all parsers will need * that functionality and so they do not need to implement it themsleves. */ static inline rsRetVal ParsePRI(msg_t *pMsg) { int pri; uchar *msg; int lenMsg; int iPriText; DEFiRet; /* pull PRI */ lenMsg = pMsg->iLenRawMsg; msg = pMsg->pszRawMsg; pri = DEFUPRI; iPriText = 0; if(pMsg->msgFlags & NO_PRI_IN_RAW) { /* In this case, simply do so as if the pri would be right at top */ MsgSetAfterPRIOffs(pMsg, 0); } else { if(*msg == '<') { /* while we process the PRI, we also fill the PRI textual representation * inside the msg object. This may not be ideal from an OOP point of view, * but it offers us performance... */ pri = 0; while(--lenMsg > 0 && isdigit((int) *++msg)) { pri = 10 * pri + (*msg - '0'); } if(*msg == '>') ++msg; if(pri & ~(LOG_FACMASK|LOG_PRIMASK)) pri = DEFUPRI; } } pMsg->iFacility = LOG_FAC(pri); pMsg->iSeverity = LOG_PRI(pri); MsgSetAfterPRIOffs(pMsg, msg - pMsg->pszRawMsg); RETiRet; } /* Parse a received message. The object's rawmsg property is taken and * parsed according to the relevant standards. This can later be * extended to support configured parsers. * rgerhards, 2008-10-09 */ static rsRetVal ParseMsg(msg_t *pMsg) { rsRetVal localRet; parserList_t *pParserList; parser_t *pParser; sbool bIsSanitized; sbool bPRIisParsed; static int iErrMsgRateLimiter = 0; DEFiRet; if(pMsg->iLenRawMsg == 0) ABORT_FINALIZE(RS_RET_EMPTY_MSG); # ifdef USE_NETZIP CHKiRet(uncompressMessage(pMsg)); # endif /* we take the risk to print a non-sanitized string, because this is the best we can get * (and that functionality is too important for debugging to drop it...). */ DBGPRINTF("msg parser: flags %x, from '%s', msg '%.50s'\n", pMsg->msgFlags, (pMsg->msgFlags & NEEDS_DNSRESOL) ? UCHAR_CONSTANT("~NOTRESOLVED~") : getRcvFrom(pMsg), pMsg->pszRawMsg); /* we now need to go through our list of parsers and see which one is capable of * parsing the message. Note that the first parser that requires message sanitization * will cause it to happen. After that, access to the unsanitized message is no * loger possible. */ pParserList = ruleset.GetParserList(pMsg); if(pParserList == NULL) { pParserList = pDfltParsLst; } DBGPRINTF("parse using parser list %p%s.\n", pParserList, (pParserList == pDfltParsLst) ? " (the default list)" : ""); bIsSanitized = FALSE; bPRIisParsed = FALSE; while(pParserList != NULL) { pParser = pParserList->pParser; if(pParser->bDoSanitazion && bIsSanitized == FALSE) { CHKiRet(SanitizeMsg(pMsg)); if(pParser->bDoPRIParsing && bPRIisParsed == FALSE) { CHKiRet(ParsePRI(pMsg)); bPRIisParsed = TRUE; } bIsSanitized = TRUE; } localRet = pParser->pModule->mod.pm.parse(pMsg); dbgprintf("Parser '%s' returned %d\n", pParser->pName, localRet); if(localRet != RS_RET_COULD_NOT_PARSE) break; pParserList = pParserList->pNext; } /* We need to log a warning message and drop the message if we did not find a parser. * Note that we log at most the first 1000 message, as this may very well be a problem * that causes a message generation loop. We do not synchronize that counter, it doesn't * matter if we log a handful messages more than we should... */ if(localRet != RS_RET_OK) { if(++iErrMsgRateLimiter > 1000) { errmsg.LogError(0, localRet, "Error: one message could not be processed by " "any parser, message is being discarded (start of raw msg: '%.50s')", pMsg->pszRawMsg); } DBGPRINTF("No parser could process the message (state %d), we need to discard it.\n", localRet); ABORT_FINALIZE(localRet); } /* "finalize" message object */ pMsg->msgFlags &= ~NEEDS_PARSING; /* this message is now parsed */ finalize_it: RETiRet; } /* set the parser name - string is copied over, call can continue to use it, * but must free it if desired. */ static rsRetVal SetName(parser_t *pThis, uchar *name) { DEFiRet; ISOBJ_TYPE_assert(pThis, parser); assert(name != NULL); if(pThis->pName != NULL) { free(pThis->pName); pThis->pName = NULL; } CHKmalloc(pThis->pName = ustrdup(name)); finalize_it: RETiRet; } /* set a pointer to "our" module. Note that no module * pointer must already be set. */ static rsRetVal SetModPtr(parser_t *pThis, modInfo_t *pMod) { ISOBJ_TYPE_assert(pThis, parser); assert(pMod != NULL); assert(pThis->pModule == NULL); pThis->pModule = pMod; return RS_RET_OK; } /* Specify if we should do standard message sanitazion before we pass the data * down to the parser. */ static rsRetVal SetDoSanitazion(parser_t *pThis, int bDoIt) { ISOBJ_TYPE_assert(pThis, parser); pThis->bDoSanitazion = bDoIt; return RS_RET_OK; } /* Specify if we should do standard PRI parsing before we pass the data * down to the parser module. */ static rsRetVal SetDoPRIParsing(parser_t *pThis, int bDoIt) { ISOBJ_TYPE_assert(pThis, parser); pThis->bDoPRIParsing = bDoIt; return RS_RET_OK; } /* queryInterface function-- rgerhards, 2009-11-03 */ BEGINobjQueryInterface(parser) CODESTARTobjQueryInterface(parser) if(pIf->ifVersion != parserCURR_IF_VERSION) { /* check for current version, increment on each change */ ABORT_FINALIZE(RS_RET_INTERFACE_NOT_SUPPORTED); } /* ok, we have the right interface, so let's fill it * Please note that we may also do some backwards-compatibility * work here (if we can support an older interface version - that, * of course, also affects the "if" above). */ pIf->Construct = parserConstruct; pIf->ConstructFinalize = parserConstructFinalize; pIf->Destruct = parserDestruct; pIf->SetName = SetName; pIf->SetModPtr = SetModPtr; pIf->SetDoSanitazion = SetDoSanitazion; pIf->SetDoPRIParsing = SetDoPRIParsing; pIf->ParseMsg = ParseMsg; pIf->SanitizeMsg = SanitizeMsg; pIf->InitParserList = InitParserList; pIf->DestructParserList = DestructParserList; pIf->AddParserToList = AddParserToList; pIf->AddDfltParser = AddDfltParser; pIf->FindParser = FindParser; finalize_it: ENDobjQueryInterface(parser) /* Reset config variables to default values. * rgerhards, 2007-07-17 */ static rsRetVal resetConfigVariables(uchar __attribute__((unused)) *pp, void __attribute__((unused)) *pVal) { cCCEscapeChar = '#'; bEscapeCCOnRcv = 1; /* default is to escape control characters */ bEscape8BitChars = 0; /* default is to escape control characters */ bEscapeTab = 1; /* default is to escape control characters */ bDropTrailingLF = 1; /* default is to drop trailing LF's on reception */ return RS_RET_OK; } /* This destroys the master parserlist and all of its parser entries. MUST only be * done when the module is shut down. Parser modules are NOT unloaded, rsyslog * does that at a later stage for all dynamically loaded modules. */ static void destroyMasterParserList(void) { parserList_t *pParsLst; parserList_t *pParsLstDel; pParsLst = pParsLstRoot; while(pParsLst != NULL) { parserDestruct(&pParsLst->pParser); pParsLstDel = pParsLst; pParsLst = pParsLst->pNext; free(pParsLstDel); } } /* Exit our class. * rgerhards, 2009-11-04 */ BEGINObjClassExit(parser, OBJ_IS_CORE_MODULE) /* class, version */ DestructParserList(&pDfltParsLst); destroyMasterParserList(); objRelease(glbl, CORE_COMPONENT); objRelease(errmsg, CORE_COMPONENT); objRelease(datetime, CORE_COMPONENT); objRelease(ruleset, CORE_COMPONENT); ENDObjClassExit(parser) /* Initialize the parser class. Must be called as the very first method * before anything else is called inside this class. * rgerhards, 2009-11-02 */ BEGINObjClassInit(parser, 1, OBJ_IS_CORE_MODULE) /* class, version */ /* request objects we use */ CHKiRet(objUse(glbl, CORE_COMPONENT)); CHKiRet(objUse(errmsg, CORE_COMPONENT)); CHKiRet(objUse(datetime, CORE_COMPONENT)); CHKiRet(objUse(ruleset, CORE_COMPONENT)); CHKiRet(regCfSysLineHdlr((uchar *)"controlcharacterescapeprefix", 0, eCmdHdlrGetChar, NULL, &cCCEscapeChar, NULL)); CHKiRet(regCfSysLineHdlr((uchar *)"droptrailinglfonreception", 0, eCmdHdlrBinary, NULL, &bDropTrailingLF, NULL)); CHKiRet(regCfSysLineHdlr((uchar *)"escapecontrolcharactersonreceive", 0, eCmdHdlrBinary, NULL, &bEscapeCCOnRcv, NULL)); CHKiRet(regCfSysLineHdlr((uchar *)"escape8bitcharactersonreceive", 0, eCmdHdlrBinary, NULL, &bEscape8BitChars, NULL)); CHKiRet(regCfSysLineHdlr((uchar *)"escapecontrolcharactertab", 0, eCmdHdlrBinary, NULL, &bEscapeTab, NULL)); CHKiRet(regCfSysLineHdlr((uchar *)"resetconfigvariables", 1, eCmdHdlrCustomHandler, resetConfigVariables, NULL, NULL)); InitParserList(&pParsLstRoot); InitParserList(&pDfltParsLst); ENDObjClassInit(parser)