From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 19 Mar 2021 02:21:58 +0000 (-0400)
Subject: Don't leak malloc'd error string in libpqrcv_check_conninfo().
X-Git-Tag: REL_13_3~75
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=12354839e874c1f6ebc5e1e5ebc1c6b5519eeea0;p=thirdparty%2Fpostgresql.git

Don't leak malloc'd error string in libpqrcv_check_conninfo().

We leaked the error report from PQconninfoParse, when there was
one.  It seems unlikely that real usage patterns would repeat
the failure often enough to create serious bloat, but let's
back-patch anyway to keep the code similar in all branches.

Found via valgrind testing.
Back-patch to v10 where this code was added.

Discussion: https://postgr.es/m/3816764.1616104288@sss.pgh.pa.us
---

diff --git a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
index 80725fe9130..98b01647b7b 100644
--- a/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
+++ b/src/backend/replication/libpqwalreceiver/libpqwalreceiver.c
@@ -246,9 +246,15 @@ libpqrcv_check_conninfo(const char *conninfo)
 
 	opts = PQconninfoParse(conninfo, &err);
 	if (opts == NULL)
+	{
+		/* The error string is malloc'd, so we must free it explicitly */
+		char	   *errcopy = err ? pstrdup(err) : "out of memory";
+
+		PQfreemem(err);
 		ereport(ERROR,
 				(errcode(ERRCODE_SYNTAX_ERROR),
-				 errmsg("invalid connection string syntax: %s", err)));
+				 errmsg("invalid connection string syntax: %s", errcopy)));
+	}
 
 	PQconninfoFree(opts);
 }