Re: [PATCH 1/1] selinx: Add getattr to class udp_socket

[Stefano Brivio <sbrivio@redhat.com>]

On Thu,  1 May 2025 11:54:07 +0200
Janne Grunau <janne-psst@jannau.net> wrote:

> Commit 59cc89f ("udp, udp_flow: Track our specific address on socket
> interfaces") added a getsockname() call in udp_flow_new(). This requires
> getattr. Fixes "Flow 0 (UDP flow): Unable to determine local address:
> Permission denied" errors in muvm/passt on Fedora Linux 42 with SELinux.
> 
> The SELinux audit message is
> 
> | type=AVC msg=audit(1746083799.606:235): avc:  denied  { getattr } for
> |   pid=2961 comm="passt" laddr=127.0.0.1 lport=49221
> |   faddr=127.0.0.53 fport=53
> |   scontext=unconfined_u:unconfined_r:passt_t:s0-s0:c0.c1023
> |   tcontext=unconfined_u:unconfined_r:passt_t:s0-s0:c0.c1023
> |   tclass=udp_socket permissive=0
> 
> Fixes: 59cc89f ("udp, udp_flow: Track our specific address on socket interfaces")
> Signed-off-by: Janne Grunau <janne-psst@jannau.net>

Whoops. Applied. Thanks for fixing this, and welcome to the git log!

By the way, if somebody is wondering:

> ---
>  contrib/selinux/passt.te | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/contrib/selinux/passt.te b/contrib/selinux/passt.te
> index f8ea672..eb9ce72 100644
> --- a/contrib/selinux/passt.te
> +++ b/contrib/selinux/passt.te
> @@ -49,7 +49,7 @@ require {
>  	type proc_net_t;
>  	type node_t;
>  	class tcp_socket { create accept listen name_bind name_connect getattr ioctl };
> -	class udp_socket { create accept listen };
> +	class udp_socket { create accept listen getattr };
>  	class icmp_socket { bind create name_bind node_bind setopt read write };
>  	class sock_file { create unlink write };
>  
> @@ -133,7 +133,7 @@ allow passt_t node_t:icmp_socket { name_bind node_bind };
>  allow passt_t port_t:icmp_socket name_bind;
>  
>  allow passt_t self:tcp_socket { create getopt setopt connect bind listen accept shutdown read write getattr ioctl };
> -allow passt_t self:udp_socket { create getopt setopt connect bind read write };
> +allow passt_t self:udp_socket { create getopt setopt connect bind read write getattr };

...this already works with pasta's (pasta_t) profile because there we
need a bunch of other things (for "spliced" sockets) and I used the
create_stream_socket_perms macro instead, which already includes getattr.

But including getattr here is enough for passt, no need to allow
everything else.

>  allow passt_t self:icmp_socket { bind create setopt read write };
>  
>  allow passt_t user_tmp_t:dir { add_name write };

-- 
Stefano