Fix search_path to a safe value during maintenance operations.

While executing maintenance operations (ANALYZE, CLUSTER, REFRESH
MATERIALIZED VIEW, REINDEX, or VACUUM), set search_path to
'pg_catalog, pg_temp' to prevent inconsistent behavior.

Functions that are used for functional indexes, in index expressions,
or in materialized views and depend on a different search path must be
declared with CREATE FUNCTION ... SET search_path='...'.

This change was previously committed as 05e1737351, then reverted in
commit 2fcc7ee7af because it was too late in the cycle.

Preparation for the MAINTAIN privilege, which was previously reverted
due to search_path manipulation hazards.

Discussion: https://postgr.es/m/d4ccaf3658cb3c281ec88c851a09733cd9482f22.camel@j-davis.com
Discussion: https://postgr.es/m/E1q7j7Y-000z1H-Hr%40gemulon.postgresql.org
Discussion: https://postgr.es/m/e44327179e5c9015c8dda67351c04da552066017.camel%40j-davis.com
Reviewed-by: Greg Stark, Nathan Bossart, Noah Misch

5 files changed, 16 insertions, 0 deletions

diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
index 4aee1098cf6..b054ba18155 100644
--- a/src/backend/commands/analyze.c
+++ b/src/backend/commands/analyze.c
@@ -339,6 +339,8 @@ do_analyze_rel(Relation onerel, VacuumParams *params,
 	SetUserIdAndSecContext(onerel->rd_rel->relowner,
 						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
 	save_nestlevel = NewGUCNestLevel();
+	SetConfigOption("search_path", GUC_SAFE_SEARCH_PATH, PGC_USERSET,
+					PGC_S_SESSION);
 
 	/* measure elapsed time iff autovacuum logging requires it */
 	if (AmAutoVacuumWorkerProcess() && params->log_min_duration >= 0)
diff --git a/src/backend/commands/cluster.c b/src/backend/commands/cluster.c
index 661fdef9b33..2b69dc0558f 100644
--- a/src/backend/commands/cluster.c
+++ b/src/backend/commands/cluster.c
@@ -350,6 +350,8 @@ cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
 	SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
 						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
 	save_nestlevel = NewGUCNestLevel();
+	SetConfigOption("search_path", GUC_SAFE_SEARCH_PATH, PGC_USERSET,
+					PGC_S_SESSION);
 
 	/*
 	 * Since we may open a new transaction for each relation, we have to check
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index cde1ee7432d..d0813278eac 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -585,6 +585,10 @@ DefineIndex(Oid tableId,
 
 	root_save_nestlevel = NewGUCNestLevel();
 
+	if (!IsBootstrapProcessingMode())
+		SetConfigOption("search_path", GUC_SAFE_SEARCH_PATH, PGC_USERSET,
+						PGC_S_SESSION);
+
 	/*
 	 * Some callers need us to run with an empty default_tablespace; this is a
 	 * necessary hack to be able to reproduce catalog state accurately when
@@ -1340,6 +1344,8 @@ DefineIndex(Oid tableId,
 				SetUserIdAndSecContext(childrel->rd_rel->relowner,
 									   child_save_sec_context | SECURITY_RESTRICTED_OPERATION);
 				child_save_nestlevel = NewGUCNestLevel();
+				SetConfigOption("search_path", GUC_SAFE_SEARCH_PATH, PGC_USERSET,
+								PGC_S_SESSION);
 
 				/*
 				 * Don't try to create indexes on foreign tables, though. Skip
@@ -3881,6 +3887,8 @@ ReindexRelationConcurrently(const ReindexStmt *stmt, Oid relationOid, const Rein
 		SetUserIdAndSecContext(heapRel->rd_rel->relowner,
 							   save_sec_context | SECURITY_RESTRICTED_OPERATION);
 		save_nestlevel = NewGUCNestLevel();
+		SetConfigOption("search_path", GUC_SAFE_SEARCH_PATH, PGC_USERSET,
+						PGC_S_SESSION);
 
 		/* determine safety of this index for set_indexsafe_procflags */
 		idx->safe = (indexRel->rd_indexprs == NIL &&
diff --git a/src/backend/commands/matview.c b/src/backend/commands/matview.c
index 2f1d897cf1d..1887cd60ea6 100644
--- a/src/backend/commands/matview.c
+++ b/src/backend/commands/matview.c
@@ -173,6 +173,8 @@ ExecRefreshMatView(RefreshMatViewStmt *stmt, const char *queryString,
 	SetUserIdAndSecContext(relowner,
 						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
 	save_nestlevel = NewGUCNestLevel();
+	SetConfigOption("search_path", GUC_SAFE_SEARCH_PATH, PGC_USERSET,
+					PGC_S_SESSION);
 
 	/* Make sure it is a materialized view. */
 	if (matviewRel->rd_rel->relkind != RELKIND_MATVIEW)
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index bd2309967e0..02d0dc4aba7 100644
--- a/src/backend/commands/vacuum.c
+++ b/src/backend/commands/vacuum.c
@@ -2166,6 +2166,8 @@ vacuum_rel(Oid relid, RangeVar *relation, VacuumParams *params,
 	SetUserIdAndSecContext(rel->rd_rel->relowner,
 						   save_sec_context | SECURITY_RESTRICTED_OPERATION);
 	save_nestlevel = NewGUCNestLevel();
+	SetConfigOption("search_path", GUC_SAFE_SEARCH_PATH, PGC_USERSET,
+					PGC_S_SESSION);
 
 	/*
 	 * If PROCESS_MAIN is set (the default), it's time to vacuum the main