netdev - Re: [PATCH net] selinux: do not report error on connect(AF

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Date:   Wed, 8 May 2019 10:50:19 -0300
From:   Marcelo Ricardo Leitner <marcelo.leitner@...il.com>
To:     Paolo Abeni <pabeni@...hat.com>
Cc:     Paul Moore <paul@...l-moore.com>, selinux@...r.kernel.org,
        netdev@...r.kernel.org, Tom Deseyn <tdeseyn@...hat.com>,
        Richard Haines <richard_c_haines@...nternet.com>
Subject: Re: [PATCH net] selinux: do not report error on connect(AF_UNSPEC)

On Wed, May 08, 2019 at 03:32:51PM +0200, Paolo Abeni wrote:
> calling connect(AF_UNSPEC) on an already connected TCP socket is an
> established way to disconnect() such socket. After commit 68741a8adab9
> ("selinux: Fix ltp test connect-syscall failure") it no longer works
> and, in the above scenario connect() fails with EAFNOSUPPORT.
> 
> Fix the above falling back to the generic/old code when the address family
> is not AF_INET{4,6}, but leave the SCTP code path untouched, as it has
> specific constraints.
> 
> Fixes: 68741a8adab9 ("selinux: Fix ltp test connect-syscall failure")
> Reported-by: Tom Deseyn <tdeseyn@...hat.com>
> Signed-off-by: Paolo Abeni <pabeni@...hat.com>

Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@...il.com>

> ---
>  security/selinux/hooks.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index c61787b15f27..d82b87c16b0a 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -4649,7 +4649,7 @@ static int selinux_socket_connect_helper(struct socket *sock,
>  		struct lsm_network_audit net = {0,};
>  		struct sockaddr_in *addr4 = NULL;
>  		struct sockaddr_in6 *addr6 = NULL;
> -		unsigned short snum;
> +		unsigned short snum = 0;
>  		u32 sid, perm;
>  
>  		/* sctp_connectx(3) calls via selinux_sctp_bind_connect()
> @@ -4674,12 +4674,12 @@ static int selinux_socket_connect_helper(struct socket *sock,
>  			break;
>  		default:
>  			/* Note that SCTP services expect -EINVAL, whereas
> -			 * others expect -EAFNOSUPPORT.
> +			 * others must handle this at the protocol level:
> +			 * connect(AF_UNSPEC) on a connected socket is
> +			 * a documented way disconnect the socket.
>  			 */
>  			if (sksec->sclass == SECCLASS_SCTP_SOCKET)
>  				return -EINVAL;
> -			else
> -				return -EAFNOSUPPORT;
>  		}
>  
>  		err = sel_netport_sid(sk->sk_protocol, snum, &sid);
> -- 
> 2.20.1
>