From: Fujii Masao <fujii@postgresql.org>
Date: Mon, 25 May 2026 16:07:24 +0000 (+0900)
Subject: dblink: Reject use_scram_passthrough on foreign-data wrappers
X-Git-Tag: REL_19_BETA1~54
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=e2b8813403b19609a3f194b1d4cdb88df5aa4c7d;p=thirdparty%2Fpostgresql.git

dblink: Reject use_scram_passthrough on foreign-data wrappers

Previously, dblink accepted the use_scram_passthrough option on
foreign-data wrappers via ALTER FOREIGN DATA WRAPPER dblink_fdw
OPTIONS, even though the setting had no effect there.

use_scram_passthrough should be only meaningful for foreign servers
and user mappings, so this commit updates dblink to accept the option
only in those contexts.

Backpatch to v18, where use_scram_passthrough was introduced.

Author: Matheus Alcantara <matheusssilv97@gmail.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/CAHGQGwEJ8rZjmbOvCicyr4vbuLio082bNTde0WNoSWaWr9wVcg@mail.gmail.com
Backpatch-through: 18
---

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index c631c1aefcc..448d469aba8 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -3116,8 +3116,15 @@ static bool
 is_valid_dblink_fdw_option(const PQconninfoOption *options, const char *option,
 						   Oid context)
 {
-	if (strcmp(option, "use_scram_passthrough") == 0)
-		return true;
+	/*
+	 * These options are only valid for foreign server or user mapping
+	 * contexts
+	 */
+	if (context == ForeignServerRelationId || context == UserMappingRelationId)
+	{
+		if (strcmp(option, "use_scram_passthrough") == 0)
+			return true;
+	}
 
 	return is_valid_dblink_option(options, option, context);
 }
diff --git a/contrib/dblink/expected/dblink.out b/contrib/dblink/expected/dblink.out
index c70c79574fd..1d2759def9e 100644
--- a/contrib/dblink/expected/dblink.out
+++ b/contrib/dblink/expected/dblink.out
@@ -1220,6 +1220,11 @@ SHOW intervalstyle;
  postgres
 (1 row)
 
+-- Check that adding use_scram_passthrough option on an foreign data wrapper is
+-- not allowed
+ALTER FOREIGN DATA WRAPPER dblink_fdw OPTIONS(add use_scram_passthrough 'true');
+ERROR:  invalid option "use_scram_passthrough"
+HINT:  There are no valid options in this context.
 -- Clean up GUC-setting tests
 SELECT dblink_disconnect('myconn');
  dblink_disconnect 
diff --git a/contrib/dblink/sql/dblink.sql b/contrib/dblink/sql/dblink.sql
index 365b21036e8..d67a0a5992e 100644
--- a/contrib/dblink/sql/dblink.sql
+++ b/contrib/dblink/sql/dblink.sql
@@ -635,6 +635,10 @@ FROM dblink_fetch('myconn','error_cursor', 1) AS t(i int);
 SHOW datestyle;
 SHOW intervalstyle;
 
+-- Check that adding use_scram_passthrough option on an foreign data wrapper is
+-- not allowed
+ALTER FOREIGN DATA WRAPPER dblink_fdw OPTIONS(add use_scram_passthrough 'true');
+
 -- Clean up GUC-setting tests
 SELECT dblink_disconnect('myconn');
 RESET datestyle;