imap: Fixed a crash with tb-extra-mailbox-sep workaround and selecting "ns-prefix...

diff --git a/src/imap/imap-commands-util.c b/src/imap/imap-commands-util.c
index 2340949401c8399374eff90eb95b17ffa2dc0d64..1904e204140ee5c15d590d575a1acc746454661f 100644 (file)
--- a/src/imap/imap-commands-util.c
+++ b/src/imap/imap-commands-util.c
@@ -49,6 +49,7 @@ client_find_namespace(struct client_command_context *cmd, const char *mailbox,
        storage_name_len = strlen(storage_name);
        if ((cmd->client->set->parsed_workarounds &
                        WORKAROUND_TB_EXTRA_MAILBOX_SEP) != 0 &&
+           storage_name_len > 0 &&
            storage_name[storage_name_len-1] == ns->real_sep) {
                /* drop the extra trailing hierarchy separator */
                storage_name = t_strndup(storage_name, storage_name_len-1);