From f81ce4a0f6985dc70a549f08b4f94306e65b86a8 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Thu, 29 Aug 2002 21:50:36 +0000
Subject: [PATCH] Prevent problem with extra-long password packets from
 allocating lots of memory.

Neil Conway
---
 src/backend/libpq/auth.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 97c928d900..fb43f8e4af 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.86 2002/08/29 03:22:01 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/libpq/auth.c,v 1.87 2002/08/29 21:50:36 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -709,6 +709,20 @@ recv_and_check_password_packet(Port *port)
 	if (pq_eof() == EOF || pq_getint(&len, 4) == EOF)
 		return STATUS_EOF;		/* client didn't want to send password */
 
+	/*
+	 * Since the remote client has not yet been authenticated, we need
+	 * to be careful when using the data they send us. The 8K limit is
+	 * arbitrary, and somewhat bogus: the intent is to ensure we don't
+	 * allocate an enormous chunk of memory.
+	 */
+
+	if (len < 1 || len > 8192)
+	{
+		elog(LOG, "Invalid password packet length: %d; "
+			 "must satisfy 1 <= length <= 8192", len);
+		return STATUS_EOF;
+	}
+
 	initStringInfo(&buf);
 	if (pq_getstr(&buf) == EOF) /* receive password */
 	{