From 1f42e1cb68e6bdd2b65620cd57c797a848d9be8c Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Thu, 3 Jan 2008 21:28:55 +0000
Subject: [PATCH] The original patch to disallow non-passworded connections to
 non-superusers failed to cover all the ways in which a connection can be
 initiated in dblink. Plug the remaining holes.  Also, disallow transient
 connections in functions for which that feature makes no sense (because they
 are only sensible as part of a sequence of operations on the same
 connection).  Joe Conway

Security: CVE-2007-6601
---
 contrib/dblink/dblink.c | 52 ++++++++++++++++++++++++-----------------
 1 file changed, 31 insertions(+), 21 deletions(-)

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index d12af7810d4..0a2d70e6b69 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -31,6 +31,8 @@
  */
 #include "postgres.h"
 
+#include <ctype.h>
+
 #include "libpq-fe.h"
 #include "fmgr.h"
 #include "funcapi.h"
@@ -85,6 +87,7 @@ static HeapTuple get_tuple_of_interest(Oid relid, int16 *pkattnums, int16 pknuma
 static Oid	get_relid_from_relname(text *relname_text);
 static char *generate_relation_name(Oid relid);
 static char *connstr_strip_password(const char *connstr);
+static void dblink_security_check(PGconn *conn, remoteConn *rcon, const char *connstr);
 
 /* Global */
 List	   *res_id = NIL;
@@ -159,6 +162,7 @@ typedef struct remoteConnHashEnt
 			else \
 			{ \
 				connstr = conname_or_str; \
+				dblink_security_check(conn, rcon, connstr); \
 				conn = PQconnectdb(connstr); \
 				if (PQstatus(conn) == CONNECTION_BAD) \
 				{ \
@@ -200,27 +204,8 @@ dblink_connect(PG_FUNCTION_ARGS)
 	if (connname)
 		rcon = (remoteConn *) palloc(sizeof(remoteConn));
 
-	/* for non-superusers, check that server requires a password */
-	if (!superuser())
-	{
-		/* this attempt must fail */
-		conn = PQconnectdb(connstr_strip_password(connstr));
-
-		if (PQstatus(conn) == CONNECTION_OK)
-		{
-			PQfinish(conn);
-			if (rcon)
-				pfree(rcon);
-
-			ereport(ERROR,
-					(errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
-					 errmsg("password is required"),
-					 errdetail("Non-superuser cannot connect if the server does not request a password."),
-					 errhint("Target server's authentication method must be changed.")));
-		}
-		else
-			PQfinish(conn);
-	}
+	/* check password used if not superuser */
+	dblink_security_check(conn, rcon, connstr);
 	conn = PQconnectdb(connstr);
 
 	MemoryContextSwitchTo(oldcontext);
@@ -2124,3 +2109,28 @@ connstr_strip_password(const char *connstr)
 
 	return result.data;
 }
+
+static void
+dblink_security_check(PGconn *conn, remoteConn *rcon, const char *connstr)
+{
+	if (!superuser())
+	{
+		/* this attempt must fail */
+		conn = PQconnectdb(connstr_strip_password(connstr));
+
+		if (PQstatus(conn) == CONNECTION_OK)
+		{
+			PQfinish(conn);
+			if (rcon)
+				pfree(rcon);
+
+			ereport(ERROR,
+					(errcode(ERRCODE_S_R_E_PROHIBITED_SQL_STATEMENT_ATTEMPTED),
+					 errmsg("password is required"),
+					 errdetail("Non-superuser cannot connect if the server does not request a password."),
+					 errhint("Target server's authentication method must be changed.")));
+		}
+		else
+			PQfinish(conn);
+	}
+}