Re: [PATCH v2] selinux: vsock: Set SID for socket returned by accept()

[David Brazdil <dbrazdil@google.com>]

On Fri, Mar 19, 2021 at 01:05:41PM +0000, David Brazdil wrote:
> For AF_VSOCK, accept() currently returns sockets that are unlabelled.
> Other socket families derive the child's SID from the SID of the parent
> and the SID of the incoming packet. This is typically done as the
> connected socket is placed in the queue that accept() removes from.
> 
> Reuse the existing 'security_sk_clone' hook to copy the SID from the
> parent (server) socket to the child. There is no packet SID in this
> case.
> 
> Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
Cc: <stable@vger.kernel.org>
> Signed-off-by: David Brazdil <dbrazdil@google.com>
> ---
> Tested on Android AOSP and Fedora 33 with v5.12-rc3.
> Unit test is available here:
>   https://github.com/SELinuxProject/selinux-testsuite/pull/75
> 
> Changes since v1:
>   * reuse security_sk_clone instead of adding a new hook
> 
>  net/vmw_vsock/af_vsock.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
> index 5546710d8ac1..bc7fb9bf3351 100644
> --- a/net/vmw_vsock/af_vsock.c
> +++ b/net/vmw_vsock/af_vsock.c
> @@ -755,6 +755,7 @@ static struct sock *__vsock_create(struct net *net,
>  		vsk->buffer_size = psk->buffer_size;
>  		vsk->buffer_min_size = psk->buffer_min_size;
>  		vsk->buffer_max_size = psk->buffer_max_size;
> +		security_sk_clone(parent, sk);
>  	} else {
>  		vsk->trusted = ns_capable_noaudit(&init_user_ns, CAP_NET_ADMIN);
>  		vsk->owner = get_current_cred();
> -- 
> 2.31.0.rc2.261.g7f71774620-goog
>