block/nbd: don't restrict TLS usage to IP sockets

The TLS usage for NBD was restricted to IP sockets because validating
x509 certificates requires knowledge of the hostname that the client
is connecting to.

TLS does not have to use x509 certificates though, as PSK (pre-shared
keys) provide an alternative credential option. These have no
requirement for a hostname and can thus be trivially used for UNIX
sockets.

Furthermore, with the ability to overide the default hostname for
TLS validation in the previous patch, it is now also valid to want
to use x509 certificates with FD passing and UNIX sockets.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <20220304193610.3293146-6-berrange@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

1 files changed, 2 insertions, 6 deletions

diff --git a/block/nbd.c b/block/nbd.c
index 0a9b6cd..34b9429 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -1839,13 +1839,9 @@ static int nbd_process_options(BlockDriverState *bs, QDict *options,
             goto error;
         }
 
-        /* TODO SOCKET_ADDRESS_KIND_FD where fd has AF_INET or AF_INET6 */
-        if (s->saddr->type != SOCKET_ADDRESS_TYPE_INET) {
-            error_setg(errp, "TLS only supported over IP sockets");
-            goto error;
-        }
         s->tlshostname = g_strdup(qemu_opt_get(opts, "tls-hostname"));
-        if (!s->tlshostname) {
+        if (!s->tlshostname &&
+            s->saddr->type == SOCKET_ADDRESS_TYPE_INET) {
             s->tlshostname = g_strdup(s->saddr->u.inet.host);
         }
     }