[05/12] block/nbd: don't restrict TLS usage to IP sockets

Commit Message

Daniel P. Berrangé March 3, 2022, 4:03 p.m. UTC

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.

Signed-off-by: Daniel P. Berrangé <[e-mail]>
---
 block/nbd.c    | 8 ++------
 blockdev-nbd.c | 6 ------
 qemu-nbd.c     | 8 +++-----
 3 files changed, 5 insertions(+), 17 deletions(-)

Comments

Eric Blake March 4, 2022, 3:54 p.m. UTC | #1

On Thu, Mar 03, 2022 at 04:03:23PM +0000, Daniel P. Berrangé wrote:
> 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.
> 
> Signed-off-by: Daniel P. Berrangé <[e-mail]>
> ---
>  block/nbd.c    | 8 ++------
>  blockdev-nbd.c | 6 ------
>  qemu-nbd.c     | 8 +++-----
>  3 files changed, 5 insertions(+), 17 deletions(-)

Reviewed-by: Eric Blake <[e-mail]>

Patch

diff --git a/block/nbd.c b/block/nbd.c
index 113aa5d3af..3ede47dec9 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -1838,13 +1838,9 @@  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);
         }
     }
diff --git a/blockdev-nbd.c b/blockdev-nbd.c
index bdfa7ed3a5..9840d25a82 100644
--- a/blockdev-nbd.c
+++ b/blockdev-nbd.c
@@ -148,12 +148,6 @@  void nbd_server_start(SocketAddress *addr, const char *tls_creds,
         if (!nbd_server->tlscreds) {
             goto error;
         }
-
-        /* TODO SOCKET_ADDRESS_TYPE_FD where fd has AF_INET or AF_INET6 */
-        if (addr->type != SOCKET_ADDRESS_TYPE_INET) {
-            error_setg(errp, "TLS is only supported with IPv4/IPv6");
-            goto error;
-        }
     }
 
     nbd_server->tlsauthz = g_strdup(tls_authz);
diff --git a/qemu-nbd.c b/qemu-nbd.c
index be8043fb00..f4c5b247de 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -808,7 +808,9 @@  int main(int argc, char **argv)
 
     socket_activation = check_socket_activation();
     if (socket_activation == 0) {
-        setup_address_and_port(&bindto, &port);
+        if (!sockpath) {
+            setup_address_and_port(&bindto, &port);
+        }
     } else {
         /* Using socket activation - check user didn't use -p etc. */
         const char *err_msg = socket_activation_validate_opts(device, sockpath,
@@ -829,10 +831,6 @@  int main(int argc, char **argv)
     }
 
     if (tlscredsid) {
-        if (sockpath) {
-            error_report("TLS is only supported with IPv4/IPv6");
-            exit(EXIT_FAILURE);
-        }
         if (device) {
             error_report("TLS is not supported with a host device");
             exit(EXIT_FAILURE);