From a84f7dcee5a1b32c74188aa5374d30eddd24852b Mon Sep 17 00:00:00 2001
From: Alexander Barton <alex@barton.de>
Date: Wed, 11 Jun 2008 16:00:38 +0200
Subject: [PATCH] Allow mixed line terminations (CR+LF/CR/LF) in
 non-RFC-compliant mode

Up to now ngIRCd accepted CR+LF as well as a single CR or LF in "non RFC
compliant" mode (the default). But ngIRCd became confused when it received
data containing mixed line endings (e. g. "111\r222\n333\r\n").

This patch enables ngIRCd (in "non RFC compliant" mode) to detect CR+LF,
CR, and LF as equally good line termination sequences and to always end the
command after the first one detected.

Some clients (for exmaple Trilian) are that ... broken to send such mixed
line terminations ...

First patch proposed by Scott Perry <scperry@ucsd.edu>,
Thanks to Ali Shemiran <ashemira@ucsd.edu> for testing!
---
 src/ngircd/conn.c  | 35 ++++++++++++++++++++++-------------
 src/ngircd/parse.c | 10 ++++++++++
 2 files changed, 32 insertions(+), 13 deletions(-)

diff --git a/src/ngircd/conn.c b/src/ngircd/conn.c
index decfeb68..2e23ade8 100644
--- a/src/ngircd/conn.c
+++ b/src/ngircd/conn.c
@@ -1238,7 +1238,7 @@ static void
 Handle_Buffer(CONN_ID Idx)
 {
 #ifndef STRICT_RFC
-	char *ptr1, *ptr2;
+	char *ptr1, *ptr2, *first_eol;
 #endif
 	char *ptr;
 	size_t len, delta;
@@ -1280,19 +1280,28 @@ Handle_Buffer(CONN_ID Idx)
 		ptr = strstr(array_start(&My_Connections[Idx].rbuf), "\r\n");
 
 #ifndef STRICT_RFC
-		if (!ptr) {
-			/* Check for non-RFC-compliant request (only CR or
-			 * LF)? Unfortunately, there are quite a few clients
-			 * out there that do this -- incl. "mIRC" :-( */
-			delta = 1;
-			ptr1 = strchr(array_start(&My_Connections[Idx].rbuf), '\r');
-			ptr2 = strchr(array_start(&My_Connections[Idx].rbuf), '\n');
+		/* Check for non-RFC-compliant request (only CR or LF)?
+		 * Unfortunately, there are quite a few clients out there
+		 * that do this -- e. g. mIRC, BitchX, and Trillian :-( */
+		ptr1 = strchr(array_start(&My_Connections[Idx].rbuf), '\r');
+		ptr2 = strchr(array_start(&My_Connections[Idx].rbuf), '\n');
+		if (ptr) {
+			/* Check if there is a single CR or LF _before_ the
+			 * corerct CR+LF line terminator:  */
+			first_eol = ptr1 < ptr2 ? ptr1 : ptr2;
+			if (first_eol < ptr) {
+				/* Single CR or LF before CR+LF found */
+				ptr = first_eol;
+				delta = 1;
+			}
+		} else if (ptr1 || ptr2) {
+			/* No CR+LF terminated command found, but single
+			 * CR or LF found ... */
 			if (ptr1 && ptr2)
-				ptr = ptr1 > ptr2 ? ptr2 : ptr1;
-			else if (ptr1)
-				ptr = ptr1;
-			else if (ptr2)
-				ptr = ptr2;
+				ptr = ptr1 < ptr2 ? ptr1 : ptr2;
+			else
+				ptr = ptr1 ? ptr1 : ptr2;
+			delta = 1;
 		}
 #endif
 
diff --git a/src/ngircd/parse.c b/src/ngircd/parse.c
index 00ae3cd7..24de2bc8 100644
--- a/src/ngircd/parse.c
+++ b/src/ngircd/parse.c
@@ -340,12 +340,20 @@ Validate_Command( UNUSED CONN_ID Idx, UNUSED REQUEST *Req, bool *Closed )
 static bool
 Validate_Args(CONN_ID Idx, REQUEST *Req, bool *Closed)
 {
+#ifdef STRICT_RFC
 	int i;
+#endif
 
 	assert( Idx >= 0 );
 	assert( Req != NULL );
 	*Closed = false;
 
+#ifdef STRICT_RFC
+	/* CR and LF are never allowed in command parameters.
+	 * But since we do accept lines terminated only with CR or LF in
+	 * "non-RFC-compliant mode" (besides the correct CR+LF combination),
+	 * this check can only trigger in "strict RFC" mode; therefore we
+	 * optimize it away otherwise ... */
 	for (i = 0; i < Req->argc; i++) {
 		if (strchr(Req->argv[i], '\r') || strchr(Req->argv[i], '\n')) {
 			Log(LOG_ERR,
@@ -357,6 +365,8 @@ Validate_Args(CONN_ID Idx, REQUEST *Req, bool *Closed)
 			return false;
 		}
 	}
+#endif
+
 	return true;
 } /* Validate_Args */