Fix null pointer dereference in "\c" psql command.

The psql crash happened when no current connection existed.  (The second
new check is optional given today's undocumented NULL argument handling
in PQhost() etc.)  Back-patch to 9.0 (all supported versions).

diff --git a/src/bin/psql/command.c b/src/bin/psql/command.c
index cd4309c46556b1270f103a6cba95a9c6aa7f2d06..f24d0a79cc54d20cca587ef30009541432f9b376 100644 (file)
--- a/src/bin/psql/command.c
+++ b/src/bin/psql/command.c
@@ -1260,7 +1260,8 @@ do_connect(char *dbname, char *user, char *host, char *port)
         * syntax.
         */
        keep_password =
-               ((strcmp(user, PQuser(o_conn)) == 0) &&
+               (o_conn &&
+                (strcmp(user, PQuser(o_conn)) == 0) &&
                 (!host || strcmp(host, PQhost(o_conn)) == 0) &&
                 (strcmp(port, PQport(o_conn)) == 0) &&
                 !has_connection_string);