[Libguestfs] [libnbd PATCH 1/2] uri: Reject nbd:unix:/path/to/socket as invalid URI

libxml2 parses it as valid per RFC 3986, as the nbd: scheme with no authority and a relative path. This string has been used with qemu to request a Unix socket, such that nbdkit --run produces it for $nbd (compared to $unixsocket), but accepting it as a URI means that we instead try to connect to a TCP socket with a default authority (localhost, port 10809), and nbdkit ignores the path element 'unix:/path/to/socket' and you end up with a connection (or an attempt) to a completely different server. All scheme://authority forms have a path that is either empty or begins with '/'. This does not reject 'nbd:/path/to/socket' (with no authority but an absolute path), but at least that form has not been in use by qemu. Reported-by: Martin Kletzander <mkletzan(a)redhat.com&gt; --- lib/connect.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/lib/connect.c b/lib/connect.c index 96ed1ca..8b19e1e 100644 --- a/lib/connect.c +++ b/lib/connect.c @@ -291,12 +291,14 @@ nbd_unlocked_aio_connect_uri (struct nbd_handle *h, const char *raw_uri) * nbd_unlocked_set_tls_* to match... */ - /* Export name. */ + /* Export name. Insist on the scheme://[authority][/absname] form. */ if (uri->path) { if (uri->path[0] == '/') r = nbd_unlocked_set_export_name (h, &uri->path[1]); - else - r = nbd_unlocked_set_export_name (h, uri->path); + else { + set_error (EINVAL, "URI must begin with '%s://'", uri->scheme); + goto cleanup; + } } else r = nbd_unlocked_set_export_name (h, ""); -- 2.20.1