From e170b8c8c62064a16837c9838ef7a168fa9c9506 Mon Sep 17 00:00:00 2001 From: Noah Misch Date: Mon, 26 Feb 2018 07:39:44 -0800 Subject: 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 --- src/bin/pg_basebackup/streamutil.c | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'src/bin/pg_basebackup/streamutil.c') diff --git a/src/bin/pg_basebackup/streamutil.c b/src/bin/pg_basebackup/streamutil.c index 72d86570049..aa14dbbb75b 100644 --- a/src/bin/pg_basebackup/streamutil.c +++ b/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. -- cgit v1.2.3