acl: Don't break if mailbox listing returns an empty name.

diff --git a/src/plugins/acl/acl-mailbox-list.c b/src/plugins/acl/acl-mailbox-list.c
index 83cb6df0cba034a47542eb756fb1c537d64a943c..347c6d2e62d13568983853ab6ace9ff99b9bd4dd 100644 (file)
--- a/src/plugins/acl/acl-mailbox-list.c
+++ b/src/plugins/acl/acl-mailbox-list.c
@@ -224,7 +224,7 @@ acl_mailbox_list_iter_get_name(struct mailbox_list_iterate_context *ctx,
 
        name = mail_namespace_get_storage_name(ns, name);
        len = strlen(name);
-       if (name[len-1] == ns->real_sep) {
+       if (len > 0 && name[len-1] == ns->real_sep) {
                /* name ends with separator. this can happen if doing e.g.
                   LIST "" foo/% and it lists "foo/". */
                name = t_strndup(name, len-1);