Empty search_path in Autovacuum and non-psql/pgbench clients.

This makes the client programs behave as documented regardless of the
connect-time search_path and regardless of user-created objects.  Today,
a malicious user with CREATE permission on a search_path schema can take
control of certain of these clients' queries and invoke arbitrary SQL
functions under the client identity, often a superuser.  This is
exploitable in the default configuration, where all users have CREATE
privilege on schema "public".

This changes behavior of user-defined code stored in the database, like
pg_index.indexprs and pg_extension_config_dump().  If they reach code
bearing unqualified names, "does not exist" or "no schema has been
selected to create in" errors might appear.  Users may fix such errors
by schema-qualifying affected names.  After upgrading, consider watching
server logs for these errors.

The --table arguments of src/bin/scripts clients have been lax; for
example, "vacuumdb -Zt pg_am\;CHECKPOINT" performed a checkpoint.  That
now fails, but for now, "vacuumdb -Zt 'pg_am(amname);CHECKPOINT'" still
performs a checkpoint.

Back-patch to 9.3 (all supported versions).

Reviewed by Tom Lane, though this fix strategy was not his first choice.
Reported by Arseniy Sharoglazov.

Security: CVE-2018-1058

contrib/oid2name/oid2name.c

@@ -9,6 +9,7 @@
  */
 #include "postgres_fe.h"
 
+#include "fe_utils/connect.h"
 #include "libpq-fe.h"
 #include "pg_getopt.h"
 
@@ -263,6 +264,7 @@ sql_conn(struct options * my_opts)
 	PGconn	   *conn;
 	char	   *password = NULL;
 	bool		new_pass;
+	PGresult   *res;
 
 	/*
 	 * Start the connection.  Loop until we have a password if requested by
@@ -322,6 +324,17 @@ sql_conn(struct options * my_opts)
 		exit(1);
 	}
 
+	res = PQexec(conn, ALWAYS_SECURE_SEARCH_PATH_SQL);
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		fprintf(stderr, "oid2name: could not clear search_path: %s\n",
+				PQerrorMessage(conn));
+		PQclear(res);
+		PQfinish(conn);
+		exit(-1);
+	}
+	PQclear(res);
+
 	/* return the conn if good */
 	return conn;
 }

contrib/vacuumlo/vacuumlo.c

@@ -21,6 +21,7 @@
 #include <termios.h>
 #endif
 
+#include "fe_utils/connect.h"
 #include "libpq-fe.h"
 #include "pg_getopt.h"
 
@@ -135,11 +136,8 @@ vacuumlo(const char *database, const struct _param * param)
 			fprintf(stdout, "Test run: no large objects will be removed!\n");
 	}
 
-	/*
-	 * Don't get fooled by any non-system catalogs
-	 */
-	res = PQexec(conn, "SET search_path = pg_catalog");
-	if (PQresultStatus(res) != PGRES_COMMAND_OK)
+	res = PQexec(conn, ALWAYS_SECURE_SEARCH_PATH_SQL);
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
 	{
 		fprintf(stderr, "Failed to set search_path:\n");
 		fprintf(stderr, "%s", PQerrorMessage(conn));

src/backend/postmaster/autovacuum.c

@@ -528,6 +528,12 @@ AutoVacLauncherMain(int argc, char *argv[])
 	/* must unblock signals before calling rebuild_database_list */
 	PG_SETMASK(&UnBlockSig);
 
+	/*
+	 * Set always-secure search path.  Launcher doesn't connect to a database,
+	 * so this has no effect.
+	 */
+	SetConfigOption("search_path", "", PGC_SUSET, PGC_S_OVERRIDE);
+
 	/*
 	 * Force zero_damaged_pages OFF in the autovac process, even if it is set
 	 * in postgresql.conf.  We don't really want such a dangerous option being
@@ -1537,6 +1543,14 @@ AutoVacWorkerMain(int argc, char *argv[])
 
 	PG_SETMASK(&UnBlockSig);
 
+	/*
+	 * Set always-secure search path, so malicious users can't redirect user
+	 * code (e.g. pg_index.indexprs).  (That code runs in a
+	 * SECURITY_RESTRICTED_OPERATION sandbox, so malicious users could not
+	 * take control of the entire autovacuum worker in any case.)
+	 */
+	SetConfigOption("search_path", "", PGC_SUSET, PGC_S_OVERRIDE);
+
 	/*
 	 * Force zero_damaged_pages OFF in the autovac process, even if it is set
 	 * in postgresql.conf.  We don't really want such a dangerous option being

src/bin/pg_basebackup/streamutil.c

@@ -30,6 +30,7 @@
 #include "pqexpbuffer.h"
 #include "common/fe_memutils.h"
 #include "datatype/timestamp.h"
+#include "fe_utils/connect.h"
 
 #define ERRCODE_DUPLICATE_OBJECT  "42710"
 
@@ -208,6 +209,23 @@ GetConnection(void)
 	if (conn_opts)
 		PQconninfoFree(conn_opts);
 
+	/* Set always-secure search path, so malicious users can't get control. */
+	if (dbname != NULL)
+	{
+		PGresult   *res;
+
+		res = PQexec(tmpconn, ALWAYS_SECURE_SEARCH_PATH_SQL);
+		if (PQresultStatus(res) != PGRES_TUPLES_OK)
+		{
+			fprintf(stderr, _("%s: could not clear search_path: %s\n"),
+					progname, PQerrorMessage(tmpconn));
+			PQclear(res);
+			PQfinish(tmpconn);
+			exit(1);
+		}
+		PQclear(res);
+	}
+
 	/*
 	 * Ensure we have the same value of integer timestamps as the server we
 	 * are connecting to.

src/bin/pg_dump/pg_backup_db.c

@@ -12,6 +12,7 @@
 #include "postgres_fe.h"
 
 #include "dumputils.h"
+#include "fe_utils/connect.h"
 #include "fe_utils/string_utils.h"
 #include "parallel.h"
 #include "pg_backup_archiver.h"
@@ -114,6 +115,11 @@ ReconnectToServer(ArchiveHandle *AH, const char *dbname, const char *username)
 	PQfinish(AH->connection);
 	AH->connection = newConn;
 
+	/* Start strict; later phases may override this. */
+	if (PQserverVersion(AH->connection) >= 70300)
+		PQclear(ExecuteSqlQueryForSingleRow((Archive *) AH,
+											ALWAYS_SECURE_SEARCH_PATH_SQL));
+
 	return 1;
 }
 
@@ -322,6 +328,11 @@ ConnectDatabase(Archive *AHX,
 					  PQdb(AH->connection) ? PQdb(AH->connection) : "",
 					  PQerrorMessage(AH->connection));
 
+	/* Start strict; later phases may override this. */
+	if (PQserverVersion(AH->connection) >= 70300)
+		PQclear(ExecuteSqlQueryForSingleRow((Archive *) AH,
+											ALWAYS_SECURE_SEARCH_PATH_SQL));
+
 	/*
 	 * We want to remember connection's actual password, whether or not we got
 	 * it by prompting.  So we don't just store the password variable.

src/bin/pg_dump/pg_dump.c

@@ -61,6 +61,7 @@
 #include "pg_backup_db.h"
 #include "pg_backup_utils.h"
 #include "pg_dump.h"
+#include "fe_utils/connect.h"
 #include "fe_utils/string_utils.h"
 
 
@@ -982,6 +983,9 @@ setup_connection(Archive *AH, const char *dumpencoding,
 	PGconn	   *conn = GetConnection(AH);
 	const char *std_strings;
 
+	if (AH->remoteVersion >= 70300)
+		PQclear(ExecuteSqlQueryForSingleRow(AH, ALWAYS_SECURE_SEARCH_PATH_SQL));
+
 	/*
 	 * Set the client encoding if requested.
 	 */
@@ -1280,18 +1284,28 @@ expand_table_name_patterns(Archive *fout,
 
 	for (cell = patterns->head; cell; cell = cell->next)
 	{
+		/*
+		 * Query must remain ABSOLUTELY devoid of unqualified names.  This
+		 * would be unnecessary given a pg_table_is_visible() variant taking a
+		 * search_path argument.
+		 */
 		appendPQExpBuffer(query,
 						  "SELECT c.oid"
 						  "\nFROM pg_catalog.pg_class c"
-		"\n     LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace"
-					 "\nWHERE c.relkind in ('%c', '%c', '%c', '%c', '%c')\n",
+						  "\n     LEFT JOIN pg_catalog.pg_namespace n"
+						  "\n     ON n.oid OPERATOR(pg_catalog.=) c.relnamespace"
+						  "\nWHERE c.relkind OPERATOR(pg_catalog.=) ANY"
+						  "\n    (array['%c', '%c', '%c', '%c', '%c'])\n",
 						  RELKIND_RELATION, RELKIND_SEQUENCE, RELKIND_VIEW,
 						  RELKIND_MATVIEW, RELKIND_FOREIGN_TABLE);
 		processSQLNamePattern(GetConnection(fout), query, cell->val, true,
 							  false, "n.nspname", "c.relname", NULL,
 							  "pg_catalog.pg_table_is_visible(c.oid)");
 
+		ExecuteSqlStatement(fout, "RESET search_path");
 		res = ExecuteSqlQuery(fout, query->data, PGRES_TUPLES_OK);
+		PQclear(ExecuteSqlQueryForSingleRow(fout,
+											ALWAYS_SECURE_SEARCH_PATH_SQL));
 		if (strict_names && PQntuples(res) == 0)
 			exit_horribly(NULL, "no matching tables were found for pattern \"%s\"\n", cell->val);
 

src/bin/pg_dump/pg_dumpall.c

@@ -26,6 +26,7 @@
 
 #include "dumputils.h"
 #include "pg_backup.h"
+#include "fe_utils/connect.h"
 #include "fe_utils/string_utils.h"
 
 /* version string we expect back from pg_dump */
@@ -2079,12 +2080,8 @@ connectDatabase(const char *dbname, const char *connection_string,
 		exit_nicely(1);
 	}
 
-	/*
-	 * On 7.3 and later, make sure we are not fooled by non-system schemas in
-	 * the search path.
-	 */
 	if (server_version >= 70300)
-		executeCommand(conn, "SET search_path = pg_catalog");
+		PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL));
 
 	return conn;
 }

src/bin/pg_rewind/libpq_fetch.c

@@ -29,6 +29,7 @@
 #include "libpq-fe.h"
 #include "catalog/catalog.h"
 #include "catalog/pg_type.h"
+#include "fe_utils/connect.h"
 
 static PGconn *conn = NULL;
 
@@ -58,6 +59,12 @@ libpqConnect(const char *connstr)
 
 	pg_log(PG_PROGRESS, "connected to server\n");
 
+	res = PQexec(conn, ALWAYS_SECURE_SEARCH_PATH_SQL);
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+		pg_fatal("could not clear search_path: %s",
+				 PQresultErrorMessage(res));
+	PQclear(res);
+
 	/*
 	 * Check that the server is not in hot standby mode. There is no
 	 * fundamental reason that couldn't be made to work, but it doesn't

src/bin/pg_upgrade/server.c

@@ -9,6 +9,7 @@
 
 #include "postgres_fe.h"
 
+#include "fe_utils/connect.h"
 #include "fe_utils/string_utils.h"
 #include "pg_upgrade.h"
 
@@ -40,6 +41,8 @@ connectToServer(ClusterInfo *cluster, const char *db_name)
 		exit(1);
 	}
 
+	PQclear(executeQueryOrDie(conn, ALWAYS_SECURE_SEARCH_PATH_SQL));
+
 	return conn;
 }
 

src/bin/scripts/clusterdb.c

@@ -195,17 +195,21 @@ cluster_one_database(const char *dbname, bool verbose, const char *table,
 
 	PGconn	   *conn;
 
+	conn = connectDatabase(dbname, host, port, username, prompt_password,
+						   progname, echo, false, false);
+
 	initPQExpBuffer(&sql);
 
 	appendPQExpBufferStr(&sql, "CLUSTER");
 	if (verbose)
 		appendPQExpBufferStr(&sql, " VERBOSE");
 	if (table)
-		appendPQExpBuffer(&sql, " %s", table);
+	{
+		appendPQExpBufferChar(&sql, ' ');
+		appendQualifiedRelation(&sql, table, conn, progname, echo);
+	}
 	appendPQExpBufferChar(&sql, ';');
 
-	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false, false);
 	if (!executeMaintenanceCommand(conn, sql.data, echo))
 	{
 		if (table)
@@ -234,7 +238,7 @@ cluster_all_databases(bool verbose, const char *maintenance_db,
 	int			i;
 
 	conn = connectMaintenanceDatabase(maintenance_db, host, port, username,
-									  prompt_password, progname);
+									  prompt_password, progname, echo);
 	result = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", progname, echo);
 	PQfinish(conn);
 

src/bin/scripts/common.c

@@ -18,6 +18,8 @@
 #include <unistd.h>
 
 #include "common.h"
+#include "fe_utils/connect.h"
+#include "fe_utils/string_utils.h"
 
 
 static PGcancel *volatile cancelConn = NULL;
@@ -63,9 +65,10 @@ handle_help_version_opts(int argc, char *argv[],
  * as before, else we might create password exposure hazards.)
  */
 PGconn *
-connectDatabase(const char *dbname, const char *pghost, const char *pgport,
-				const char *pguser, enum trivalue prompt_password,
-				const char *progname, bool fail_ok, bool allow_password_reuse)
+connectDatabase(const char *dbname, const char *pghost,
+				const char *pgport, const char *pguser,
+				enum trivalue prompt_password, const char *progname,
+				bool echo, bool fail_ok, bool allow_password_reuse)
 {
 	PGconn	   *conn;
 	static char *password = NULL;
@@ -143,6 +146,10 @@ connectDatabase(const char *dbname, const char *pghost, const char *pgport,
 		exit(1);
 	}
 
+	if (PQserverVersion(conn) >= 70300)
+		PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL,
+							 progname, echo));
+
 	return conn;
 }
 
@@ -150,24 +157,24 @@ connectDatabase(const char *dbname, const char *pghost, const char *pgport,
  * Try to connect to the appropriate maintenance database.
  */
 PGconn *
-connectMaintenanceDatabase(const char *maintenance_db, const char *pghost,
-						   const char *pgport, const char *pguser,
-						   enum trivalue prompt_password,
-						   const char *progname)
+connectMaintenanceDatabase(const char *maintenance_db,
+						   const char *pghost, const char *pgport,
+						   const char *pguser, enum trivalue prompt_password,
+						   const char *progname, bool echo)
 {
 	PGconn	   *conn;
 
 	/* If a maintenance database name was specified, just connect to it. */
 	if (maintenance_db)
 		return connectDatabase(maintenance_db, pghost, pgport, pguser,
-							   prompt_password, progname, false, false);
+							   prompt_password, progname, echo, false, false);
 
 	/* Otherwise, try postgres first and then template1. */
 	conn = connectDatabase("postgres", pghost, pgport, pguser, prompt_password,
-						   progname, true, false);
+						   progname, echo, true, false);
 	if (!conn)
 		conn = connectDatabase("template1", pghost, pgport, pguser,
-							   prompt_password, progname, false, false);
+							   prompt_password, progname, echo, false, false);
 
 	return conn;
 }
@@ -253,6 +260,116 @@ executeMaintenanceCommand(PGconn *conn, const char *query, bool echo)
 	return r;
 }
 
+
+/*
+ * Split TABLE[(COLUMNS)] into TABLE and [(COLUMNS)] portions.  When you
+ * finish using them, pg_free(*table).  *columns is a pointer into "spec",
+ * possibly to its NUL terminator.
+ */
+static void
+split_table_columns_spec(const char *spec, int encoding,
+						 char **table, const char **columns)
+{
+	bool		inquotes = false;
+	const char *cp = spec;
+
+	/*
+	 * Find the first '(' not identifier-quoted.  Based on
+	 * dequote_downcase_identifier().
+	 */
+	while (*cp && (*cp != '(' || inquotes))
+	{
+		if (*cp == '"')
+		{
+			if (inquotes && cp[1] == '"')
+				cp++;			/* pair does not affect quoting */
+			else
+				inquotes = !inquotes;
+			cp++;
+		}
+		else
+			cp += PQmblen(cp, encoding);
+	}
+	*table = pg_strdup(spec);
+	(*table)[cp - spec] = '\0'; /* no strndup */
+	*columns = cp;
+}
+
+/*
+ * Break apart TABLE[(COLUMNS)] of "spec".  With the reset_val of search_path
+ * in effect, have regclassin() interpret the TABLE portion.  Append to "buf"
+ * the qualified name of TABLE, followed by any (COLUMNS).  Exit on failure.
+ * We use this to interpret --table=foo under the search path psql would get,
+ * in advance of "ANALYZE public.foo" under the always-secure search path.
+ */
+void
+appendQualifiedRelation(PQExpBuffer buf, const char *spec,
+						PGconn *conn, const char *progname, bool echo)
+{
+	char	   *table;
+	const char *columns;
+	PQExpBufferData sql;
+	PGresult   *res;
+	int			ntups;
+
+	/* Before 7.3, the concept of qualifying a name did not exist. */
+	if (PQserverVersion(conn) < 70300)
+	{
+		appendPQExpBufferStr(&sql, spec);
+		return;
+	}
+
+	split_table_columns_spec(spec, PQclientEncoding(conn), &table, &columns);
+
+	/*
+	 * Query must remain ABSOLUTELY devoid of unqualified names.  This would
+	 * be unnecessary given a regclassin() variant taking a search_path
+	 * argument.
+	 */
+	initPQExpBuffer(&sql);
+	appendPQExpBufferStr(&sql,
+						 "SELECT c.relname, ns.nspname\n"
+						 " FROM pg_catalog.pg_class c,"
+						 " pg_catalog.pg_namespace ns\n"
+						 " WHERE c.relnamespace OPERATOR(pg_catalog.=) ns.oid\n"
+						 "  AND c.oid OPERATOR(pg_catalog.=) ");
+	appendStringLiteralConn(&sql, table, conn);
+	appendPQExpBufferStr(&sql, "::pg_catalog.regclass;");
+
+	executeCommand(conn, "RESET search_path", progname, echo);
+
+	/*
+	 * One row is a typical result, as is a nonexistent relation ERROR.
+	 * regclassin() unconditionally accepts all-digits input as an OID; if no
+	 * relation has that OID; this query returns no rows.  Catalog corruption
+	 * might elicit other row counts.
+	 */
+	res = executeQuery(conn, sql.data, progname, echo);
+	ntups = PQntuples(res);
+	if (ntups != 1)
+	{
+		fprintf(stderr,
+				ngettext("%s: query returned %d row instead of one: %s\n",
+						 "%s: query returned %d rows instead of one: %s\n",
+						 ntups),
+				progname, ntups, sql.data);
+		PQfinish(conn);
+		exit(1);
+	}
+	appendPQExpBufferStr(buf,
+						 fmtQualifiedId(PQserverVersion(conn),
+										PQgetvalue(res, 0, 1),
+										PQgetvalue(res, 0, 0)));
+	appendPQExpBufferStr(buf, columns);
+	PQclear(res);
+	termPQExpBuffer(&sql);
+	pg_free(table);
+
+	PQclear(executeQuery(conn, ALWAYS_SECURE_SEARCH_PATH_SQL,
+						 progname, echo));
+}
+
+
 /*
  * Check yes/no answer in a localized way.  1=yes, 0=no, -1=neither.
  */

src/bin/scripts/common.h

@@ -32,11 +32,12 @@ extern void handle_help_version_opts(int argc, char *argv[],
 extern PGconn *connectDatabase(const char *dbname, const char *pghost,
 				const char *pgport, const char *pguser,
 				enum trivalue prompt_password, const char *progname,
-				bool fail_ok, bool allow_password_reuse);
+				bool echo, bool fail_ok, bool allow_password_reuse);
 
 extern PGconn *connectMaintenanceDatabase(const char *maintenance_db,
-				  const char *pghost, const char *pgport, const char *pguser,
-						enum trivalue prompt_password, const char *progname);
+						   const char *pghost, const char *pgport,
+						   const char *pguser, enum trivalue prompt_password,
+						   const char *progname, bool echo);
 
 extern PGresult *executeQuery(PGconn *conn, const char *query,
 			 const char *progname, bool echo);
@@ -47,6 +48,9 @@ extern void executeCommand(PGconn *conn, const char *query,
 extern bool executeMaintenanceCommand(PGconn *conn, const char *query,
 						  bool echo);
 
+extern void appendQualifiedRelation(PQExpBuffer buf, const char *name,
+						PGconn *conn, const char *progname, bool echo);
+
 extern bool yesno_prompt(const char *question);
 
 extern void setup_cancel_handler(void);

src/bin/scripts/createdb.c

@@ -202,7 +202,7 @@ main(int argc, char *argv[])
 		maintenance_db = "template1";
 
 	conn = connectMaintenanceDatabase(maintenance_db, host, port, username,
-									  prompt_password, progname);
+									  prompt_password, progname, echo);
 
 	if (echo)
 		printf("%s\n", sql.data);

src/bin/scripts/createlang.c

@@ -141,7 +141,7 @@ main(int argc, char *argv[])
 		static const bool translate_columns[] = {false, true};
 
 		conn = connectDatabase(dbname, host, port, username, prompt_password,
-							   progname, false, false);
+							   progname, echo, false, false);
 
 		printfPQExpBuffer(&sql, "SELECT lanname as \"%s\", "
 				"(CASE WHEN lanpltrusted THEN '%s' ELSE '%s' END) as \"%s\" "
@@ -181,7 +181,7 @@ main(int argc, char *argv[])
 			*p += ('a' - 'A');
 
 	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false, false);
+						   progname, echo, false, false);
 
 	/*
 	 * Make sure the language isn't already installed

src/bin/scripts/createuser.c

@@ -252,7 +252,7 @@ main(int argc, char *argv[])
 		login = TRI_YES;
 
 	conn = connectDatabase("postgres", host, port, username, prompt_password,
-						   progname, false, false);
+						   progname, echo, false, false);
 
 	initPQExpBuffer(&sql);
 

src/bin/scripts/dropdb.c

@@ -129,7 +129,8 @@ main(int argc, char *argv[])
 		maintenance_db = "template1";
 
 	conn = connectMaintenanceDatabase(maintenance_db,
-							host, port, username, prompt_password, progname);
+									  host, port, username, prompt_password,
+									  progname, echo);
 
 	if (echo)
 		printf("%s\n", sql.data);

src/bin/scripts/droplang.c

@@ -140,7 +140,7 @@ main(int argc, char *argv[])
 		static const bool translate_columns[] = {false, true};
 
 		conn = connectDatabase(dbname, host, port, username, prompt_password,
-							   progname, false, false);
+							   progname, echo, false, false);
 
 		printfPQExpBuffer(&sql, "SELECT lanname as \"%s\", "
 				"(CASE WHEN lanpltrusted THEN '%s' ELSE '%s' END) as \"%s\" "
@@ -182,13 +182,7 @@ main(int argc, char *argv[])
 			*p += ('a' - 'A');
 
 	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false, false);
-
-	/*
-	 * Force schema search path to be just pg_catalog, so that we don't have
-	 * to be paranoid about search paths below.
-	 */
-	executeCommand(conn, "SET search_path = pg_catalog;", progname, echo);
+						   progname, echo, false, false);
 
 	/*
 	 * Make sure the language is installed

src/bin/scripts/dropuser.c

@@ -129,7 +129,7 @@ main(int argc, char *argv[])
 					  (if_exists ? "IF EXISTS " : ""), fmtId(dropuser));
 
 	conn = connectDatabase("postgres", host, port, username, prompt_password,
-						   progname, false, false);
+						   progname, echo, false, false);
 
 	if (echo)
 		printf("%s\n", sql.data);

src/bin/scripts/reindexdb.c

@@ -282,23 +282,24 @@ reindex_one_database(const char *name, const char *dbname, const char *type,
 	PGconn	   *conn;
 
 	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false, false);
+						   progname, echo, false, false);
 
 	initPQExpBuffer(&sql);
 
-	appendPQExpBufferStr(&sql, "REINDEX");
+	appendPQExpBufferStr(&sql, "REINDEX ");
 
 	if (verbose)
-		appendPQExpBufferStr(&sql, " (VERBOSE)");
+		appendPQExpBufferStr(&sql, "(VERBOSE) ");
 
-	if (strcmp(type, "TABLE") == 0)
-		appendPQExpBuffer(&sql, " TABLE %s", name);
-	else if (strcmp(type, "INDEX") == 0)
-		appendPQExpBuffer(&sql, " INDEX %s", name);
+	appendPQExpBufferStr(&sql, type);
+	appendPQExpBufferChar(&sql, ' ');
+	if (strcmp(type, "TABLE") == 0 ||
+		strcmp(type, "INDEX") == 0)
+		appendQualifiedRelation(&sql, name, conn, progname, echo);
 	else if (strcmp(type, "SCHEMA") == 0)
-		appendPQExpBuffer(&sql, " SCHEMA %s", name);
+		appendPQExpBufferStr(&sql, name);
 	else if (strcmp(type, "DATABASE") == 0)
-		appendPQExpBuffer(&sql, " DATABASE %s", fmtId(PQdb(conn)));
+		appendPQExpBufferStr(&sql, fmtId(PQdb(conn)));
 	appendPQExpBufferChar(&sql, ';');
 
 	if (!executeMaintenanceCommand(conn, sql.data, echo))
@@ -335,7 +336,7 @@ reindex_all_databases(const char *maintenance_db,
 	int			i;
 
 	conn = connectMaintenanceDatabase(maintenance_db, host, port, username,
-									  prompt_password, progname);
+									  prompt_password, progname, echo);
 	result = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", progname, echo);
 	PQfinish(conn);
 
@@ -372,7 +373,7 @@ reindex_system_catalogs(const char *dbname, const char *host, const char *port,
 	PQExpBufferData sql;
 
 	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false, false);
+						   progname, echo, false, false);
 
 	initPQExpBuffer(&sql);
 

src/bin/scripts/t/010_clusterdb.pl

@@ -26,5 +26,5 @@ $node->safe_psql('postgres',
 );
 $node->issues_sql_like(
 	[ 'clusterdb', '-t', 'test1' ],
-	qr/statement: CLUSTER test1;/,
+	qr/statement: CLUSTER public\.test1;/,
 	'cluster specific table');

src/bin/scripts/t/090_reindexdb.pl

@@ -24,11 +24,11 @@ $node->safe_psql('postgres',
 	'CREATE TABLE test1 (a int); CREATE INDEX test1x ON test1 (a);');
 $node->issues_sql_like(
 	[ 'reindexdb', '-t', 'test1', 'postgres' ],
-	qr/statement: REINDEX TABLE test1;/,
+	qr/statement: REINDEX TABLE public\.test1;/,
 	'reindex specific table');
 $node->issues_sql_like(
 	[ 'reindexdb', '-i', 'test1x', 'postgres' ],
-	qr/statement: REINDEX INDEX test1x;/,
+	qr/statement: REINDEX INDEX public\.test1x;/,
 	'reindex specific index');
 $node->issues_sql_like(
 	[ 'reindexdb', '-S', 'pg_catalog', 'postgres' ],
@@ -40,5 +40,5 @@ $node->issues_sql_like(
 	'reindex system tables');
 $node->issues_sql_like(
 	[ 'reindexdb', '-v', '-t', 'test1', 'postgres' ],
-	qr/statement: REINDEX \(VERBOSE\) TABLE test1;/,
+	qr/statement: REINDEX \(VERBOSE\) TABLE public\.test1;/,
 	'reindex with verbose output');

src/bin/scripts/t/100_vacuumdb.pl

@@ -3,7 +3,7 @@ use warnings;
 
 use PostgresNode;
 use TestLib;
-use Test::More tests => 18;
+use Test::More tests => 23;
 
 program_help_ok('vacuumdb');
 program_version_ok('vacuumdb');
@@ -26,10 +26,32 @@ $node->issues_sql_like(
 	qr/statement: VACUUM \(FREEZE\);/,
 	'vacuumdb -F');
 $node->issues_sql_like(
-	[ 'vacuumdb', '-z', 'postgres' ],
-	qr/statement: VACUUM \(ANALYZE\);/,
-	'vacuumdb -z');
+	[ 'vacuumdb', '-zj2', 'postgres' ],
+	qr/statement: VACUUM \(ANALYZE\) pg_catalog\./,
+	'vacuumdb -zj2');
 $node->issues_sql_like(
 	[ 'vacuumdb', '-Z', 'postgres' ],
 	qr/statement: ANALYZE;/,
 	'vacuumdb -Z');
+$node->command_ok([qw(vacuumdb -Z --table=pg_am dbname=template1)],
+	'vacuumdb with connection string');
+
+$node->command_fails([qw(vacuumdb -Zt pg_am;ABORT postgres)],
+	'trailing command in "-t", without COLUMNS');
+# Unwanted; better if it failed.
+$node->command_ok([qw(vacuumdb -Zt pg_am(amname);ABORT postgres)],
+	'trailing command in "-t", with COLUMNS');
+
+$node->safe_psql('postgres', q|
+  CREATE TABLE "need""q(uot" (")x" text);
+
+  CREATE FUNCTION f0(int) RETURNS int LANGUAGE SQL AS 'SELECT $1 * $1';
+  CREATE FUNCTION f1(int) RETURNS int LANGUAGE SQL AS 'SELECT f0($1)';
+  CREATE TABLE funcidx (x int);
+  INSERT INTO funcidx VALUES (0),(1),(2),(3);
+  CREATE INDEX i0 ON funcidx ((f1(x)));
+|);
+$node->command_ok([qw|vacuumdb -Z --table="need""q(uot"(")x") postgres|],
+	'column list');
+$node->command_fails([qw|vacuumdb -Zt funcidx postgres|],
+	'unqualifed name via functional index');

src/bin/scripts/vacuumdb.c

@@ -59,7 +59,9 @@ static void vacuum_all_databases(vacuumingOptions *vacopts,
 					 const char *progname, bool echo, bool quiet);
 
 static void prepare_vacuum_command(PQExpBuffer sql, PGconn *conn,
-					   vacuumingOptions *vacopts, const char *table);
+					   vacuumingOptions *vacopts, const char *table,
+					   bool table_pre_qualified,
+					   const char *progname, bool echo);
 
 static void run_vacuum_command(PGconn *conn, const char *sql, bool echo,
 				   const char *table, const char *progname, bool async);
@@ -359,7 +361,7 @@ vacuum_one_database(const char *dbname, vacuumingOptions *vacopts,
 		   (stage >= 0 && stage < ANALYZE_NUM_STAGES));
 
 	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false, true);
+						   progname, echo, false, true);
 
 	if (!quiet)
 	{
@@ -431,7 +433,7 @@ vacuum_one_database(const char *dbname, vacuumingOptions *vacopts,
 		for (i = 1; i < concurrentCons; i++)
 		{
 			conn = connectDatabase(dbname, host, port, username, prompt_password,
-								   progname, false, true);
+								   progname, echo, false, true);
 			init_slot(slots + i, conn, progname);
 		}
 	}
@@ -457,7 +459,8 @@ vacuum_one_database(const char *dbname, vacuumingOptions *vacopts,
 		ParallelSlot *free_slot;
 		const char *tabname = cell ? cell->val : NULL;
 
-		prepare_vacuum_command(&sql, conn, vacopts, tabname);
+		prepare_vacuum_command(&sql, conn, vacopts, tabname,
+							   tables == &dbtables, progname, echo);
 
 		if (CancelRequested)
 		{
@@ -548,8 +551,8 @@ vacuum_all_databases(vacuumingOptions *vacopts,
 	int			stage;
 	int			i;
 
-	conn = connectMaintenanceDatabase(maintenance_db, host, port,
-									  username, prompt_password, progname);
+	conn = connectMaintenanceDatabase(maintenance_db, host, port, username,
+									  prompt_password, progname, echo);
 	result = executeQuery(conn,
 			"SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;",
 						  progname, echo);
@@ -612,8 +615,10 @@ vacuum_all_databases(vacuumingOptions *vacopts,
  * quoted.  The command is semicolon-terminated.
  */
 static void
-prepare_vacuum_command(PQExpBuffer sql, PGconn *conn, vacuumingOptions *vacopts,
-					   const char *table)
+prepare_vacuum_command(PQExpBuffer sql, PGconn *conn,
+					   vacuumingOptions *vacopts, const char *table,
+					   bool table_pre_qualified,
+					   const char *progname, bool echo)
 {
 	resetPQExpBuffer(sql);
 
@@ -669,7 +674,13 @@ prepare_vacuum_command(PQExpBuffer sql, PGconn *conn, vacuumingOptions *vacopts,
 	}
 
 	if (table)
-		appendPQExpBuffer(sql, " %s", table);
+	{
+		appendPQExpBufferChar(sql, ' ');
+		if (table_pre_qualified)
+			appendPQExpBufferStr(sql, table);
+		else
+			appendQualifiedRelation(sql, table, conn, progname, echo);
+	}
 	appendPQExpBufferChar(sql, ';');
 }
 

src/fe_utils/string_utils.c

@@ -927,8 +927,9 @@ processSQLNamePattern(PGconn *conn, PQExpBuffer buf, const char *pattern,
 	}
 
 	/*
-	 * Now decide what we need to emit.  Note there will be a leading "^(" in
-	 * the patterns in any case.
+	 * Now decide what we need to emit.  We may run under a hostile
+	 * search_path, so qualify EVERY name.  Note there will be a leading "^("
+	 * in the patterns in any case.
 	 */
 	if (namebuf.len > 2)
 	{
@@ -941,15 +942,18 @@ processSQLNamePattern(PGconn *conn, PQExpBuffer buf, const char *pattern,
 			WHEREAND();
 			if (altnamevar)
 			{
-				appendPQExpBuffer(buf, "(%s ~ ", namevar);
+				appendPQExpBuffer(buf,
+								  "(%s OPERATOR(pg_catalog.~) ", namevar);
 				appendStringLiteralConn(buf, namebuf.data, conn);
-				appendPQExpBuffer(buf, "\n        OR %s ~ ", altnamevar);
+				appendPQExpBuffer(buf,
+								  "\n        OR %s OPERATOR(pg_catalog.~) ",
+								  altnamevar);
 				appendStringLiteralConn(buf, namebuf.data, conn);
 				appendPQExpBufferStr(buf, ")\n");
 			}
 			else
 			{
-				appendPQExpBuffer(buf, "%s ~ ", namevar);
+				appendPQExpBuffer(buf, "%s OPERATOR(pg_catalog.~) ", namevar);
 				appendStringLiteralConn(buf, namebuf.data, conn);
 				appendPQExpBufferChar(buf, '\n');
 			}
@@ -965,7 +969,7 @@ processSQLNamePattern(PGconn *conn, PQExpBuffer buf, const char *pattern,
 		if (strcmp(schemabuf.data, "^(.*)$") != 0 && schemavar)
 		{
 			WHEREAND();
-			appendPQExpBuffer(buf, "%s ~ ", schemavar);
+			appendPQExpBuffer(buf, "%s OPERATOR(pg_catalog.~) ", schemavar);
 			appendStringLiteralConn(buf, schemabuf.data, conn);
 			appendPQExpBufferChar(buf, '\n');
 		}

src/include/fe_utils/connect.h

@@ -0,0 +1,28 @@
+/*-------------------------------------------------------------------------
+ *
+ * Interfaces in support of FE/BE connections.
+ *
+ *
+ * Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * src/include/fe_utils/connect.h
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef CONNECT_H
+#define CONNECT_H
+
+/*
+ * This SQL statement installs an always-secure search path, so malicious
+ * users can't take control.  CREATE of an unqualified name will fail, because
+ * this selects no creation schema.  This does not demote pg_temp, so it is
+ * suitable where we control the entire FE/BE connection but not suitable in
+ * SECURITY DEFINER functions.  This is portable to PostgreSQL 7.3, which
+ * introduced schemas.  When connected to an older version from code that
+ * might work with the old server, skip this.
+ */
+#define ALWAYS_SECURE_SEARCH_PATH_SQL \
+	"SELECT pg_catalog.set_config('search_path', '', false)"
+
+#endif							/* CONNECT_H */

src/tools/findoidjoins/findoidjoins.c

@@ -7,6 +7,7 @@
  */
 #include "postgres_fe.h"
 
+#include "fe_utils/connect.h"
 #include "libpq-fe.h"
 #include "pqexpbuffer.h"
 
@@ -44,6 +45,14 @@ main(int argc, char **argv)
 		exit(EXIT_FAILURE);
 	}
 
+	res = PQexec(conn, ALWAYS_SECURE_SEARCH_PATH_SQL);
+	if (!res || PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		fprintf(stderr, "sql error:  %s\n", PQerrorMessage(conn));
+		exit(EXIT_FAILURE);
+	}
+	PQclear(res);
+
 	/* Get a list of relations that have OIDs */
 
 	printfPQExpBuffer(&sql, "%s",