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

1 files changed, 10 insertions, 9 deletions

diff --git a/src/bin/scripts/reindexdb.c b/src/bin/scripts/reindexdb.c
index 3c2a8ff0b8d..bb89614d526 100644
--- a/src/bin/scripts/reindexdb.c
+++ b/src/bin/scripts/reindexdb.c
@@ -245,17 +245,18 @@ reindex_one_database(const char *name, const char *dbname, const char *type,
 	PGconn	   *conn;
 
 	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false);
+						   progname, echo, false);
 
 	initPQExpBuffer(&sql);
 
-	appendPQExpBuffer(&sql, "REINDEX");
-	if (strcmp(type, "TABLE") == 0)
-		appendPQExpBuffer(&sql, " TABLE %s", name);
-	else if (strcmp(type, "INDEX") == 0)
-		appendPQExpBuffer(&sql, " INDEX %s", name);
+	appendPQExpBufferStr(&sql, "REINDEX ");
+	appendPQExpBufferStr(&sql, type);
+	appendPQExpBufferChar(&sql, ' ');
+	if (strcmp(type, "TABLE") == 0 ||
+		strcmp(type, "INDEX") == 0)
+		appendQualifiedRelation(&sql, name, conn, progname, echo);
 	else if (strcmp(type, "DATABASE") == 0)
-		appendPQExpBuffer(&sql, " DATABASE %s", fmtId(PQdb(conn)));
+		appendPQExpBufferStr(&sql, fmtId(PQdb(conn)));
 	appendPQExpBuffer(&sql, ";\n");
 
 	if (!executeMaintenanceCommand(conn, sql.data, echo))
@@ -289,7 +290,7 @@ 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);
 
@@ -326,7 +327,7 @@ reindex_system_catalogs(const char *dbname, const char *host, const char *port,
 	PQExpBufferData sql;
 
 	conn = connectDatabase(dbname, host, port, username, prompt_password,
-						   progname, false);
+						   progname, echo, false);
 
 	initPQExpBuffer(&sql);