bugfix: message without MSG part could case a segfault

[backported from v5 commit 98d1ed504ec001728955a5bcd7916f64cd85f39f]
This actually was a "recent" regression, but I did not realize that it
was introduced by the performance optimization in v4-devel. Shame on
me for having two devel versions at the same time...

6 files changed, 27 insertions, 10 deletions

diff --git a/ChangeLog b/ChangeLog
index e9f7214f..d84a0d1c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+- bugfix: message without MSG part could case a segfault
+  [backported from v5 commit 98d1ed504ec001728955a5bcd7916f64cd85f39f]
+  This actually was a "recent" regression, but I did not realize that it
+  was introduced by the performance optimization in v4-devel. Shame on
+  me for having two devel versions at the same time...
 ---------------------------------------------------------------------------
 Version 4.5.8  [v4-beta] (rgerhards), 2010-02-10
 - enhanced doc for using PostgreSQL
diff --git a/runtime/msg.c b/runtime/msg.c
index 8e3ad314..70207075 100644
--- a/runtime/msg.c
+++ b/runtime/msg.c
@@ -1171,7 +1171,7 @@ uchar *getMSG(msg_t *pM)
 	if(pM == NULL)
 		ret = UCHAR_CONSTANT("");
 	else {
-		if(pM->offMSG == -1)
+		if(pM->iLenMSG == 0)
 			ret = UCHAR_CONSTANT("");
 		else
 			ret = pM->pszRawMsg + pM->offMSG;
@@ -1947,12 +1947,20 @@ void MsgSetHOSTNAME(msg_t *pThis, uchar* pszHOSTNAME, int lenHOSTNAME)
 
 
 /* set the offset of the MSG part into the raw msg buffer
+ * Note that the offset may be higher than the length of the raw message 
+ * (exactly by one). This can happen if we have a message that does not 
+ * contain any MSG part.
  */
 void MsgSetMSGoffs(msg_t *pMsg, short offs)
 {
 	ISOBJ_TYPE_assert(pMsg, msg);
-	pMsg->iLenMSG = pMsg->iLenRawMsg - offs;
 	pMsg->offMSG = offs;
+	if(offs > pMsg->iLenRawMsg) {
+		assert(offs - 1 == pMsg->iLenRawMsg);
+		pMsg->iLenMSG = 0;
+	} else {
+		pMsg->iLenMSG = pMsg->iLenRawMsg - offs;
+	}
 }
 
 
@@ -1986,7 +1994,8 @@ rsRetVal MsgReplaceMSG(msg_t *pThis, uchar* pszMSG, int lenMSG)
 		pThis->pszRawMsg = bufNew;
 	}
 
-	memcpy(pThis->pszRawMsg + pThis->offMSG, pszMSG, lenMSG);
+	if(lenMSG > 0)
+		memcpy(pThis->pszRawMsg + pThis->offMSG, pszMSG, lenMSG);
 	pThis->pszRawMsg[lenNew] = '\0'; /* this also works with truncation! */
 	pThis->iLenRawMsg = lenNew;
 	pThis->iLenMSG = lenMSG;
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 7adebfac..7cc25e41 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -79,6 +79,7 @@ EXTRA_DIST= 1.rstest 2.rstest 3.rstest err1.rstest \
 	   testsuites/2.parse1 \
 	   testsuites/3.parse1 \
 	   testsuites/oversizeTag-1.parse1 \
+	   testsuites/weird.parse1 \
 	   testsuites/date1.parse1 \
 	   testsuites/date2.parse1 \
 	   testsuites/date3.parse1 \
diff --git a/tests/testsuites/oversizeTag-1.parse1 b/tests/testsuites/oversizeTag-1.parse1
index 56510c63..d45ba1f2 100644
--- a/tests/testsuites/oversizeTag-1.parse1
+++ b/tests/testsuites/oversizeTag-1.parse1
@@ -1,3 +1,2 @@
-<38>Mar 27 19:06:53 source_server 0123456780123456780123456780123456789: MSG part
-38,auth,info,Mar 27 19:06:53,source_server,0123456780123456780123456780123456789,0123456780123456780123456780123456789:, MSG part
-# yet another real-life sample where we had some issues with
+<38>Mar 27 19:06:53 source_server 0123456789012345678901234567890123456789: MSG part
+38,auth,info,Mar 27 19:06:53,source_server,0123456789012345678901234567890123456789,0123456789012345678901234567890123456789:, MSG part
diff --git a/tests/testsuites/weird.parse1 b/tests/testsuites/weird.parse1
new file mode 100644
index 00000000..bc898fd4
--- /dev/null
+++ b/tests/testsuites/weird.parse1
@@ -0,0 +1,5 @@
+# some really weird samples, some of them seen in practice,
+# some other deliberately generated. The main point is that they
+# should not cause an abort...
+<14>Aug 30 23:00:05 X4711 AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+14,user,info,Aug 30 23:00:05,X4711,AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA,AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
diff --git a/tools/syslogd.c b/tools/syslogd.c
index db1e9428..3e6d51d3 100644
--- a/tools/syslogd.c
+++ b/tools/syslogd.c
@@ -1198,8 +1198,6 @@ int parseLegacySyslogMsg(msg_t *pMsg, int flags)
 	assert(pMsg != NULL);
 	assert(pMsg->pszRawMsg != NULL);
 	lenMsg = pMsg->iLenRawMsg - (pMsg->offAfterPRI + 1);
-RUNLOG_VAR("%d", pMsg->offAfterPRI);
-RUNLOG_VAR("%d", lenMsg);
 	p2parse = pMsg->pszRawMsg + pMsg->offAfterPRI; /* point to start of text, after PRI */
 
 	/* Check to see if msg contains a timestamp. We start by assuming
@@ -1255,16 +1253,16 @@ RUNLOG_VAR("%d", lenMsg);
 		bTAGCharDetected = 0;
 		if(lenMsg > 0 && flags & PARSE_HOSTNAME) {
 			i = 0;
-			while(lenMsg > 0 && (isalnum(p2parse[i]) || p2parse[i] == '.' || p2parse[i] == '.'
+			while(i < lenMsg && (isalnum(p2parse[i]) || p2parse[i] == '.' || p2parse[i] == '.'
 				|| p2parse[i] == '_' || p2parse[i] == '-') && i < CONF_TAG_MAXSIZE) {
 				bufParseHOSTNAME[i] = p2parse[i];
 				++i;
-				--lenMsg;
 			}
 
 			if(i > 0 && p2parse[i] == ' ' && isalnum(p2parse[i-1])) {
 				/* we got a hostname! */
 				p2parse += i + 1; /* "eat" it (including SP delimiter) */
+				lenMsg -= i + 1;
 				bufParseHOSTNAME[i] = '\0';
 				MsgSetHOSTNAME(pMsg, bufParseHOSTNAME, i);
 			}