netdev - Re: [RFC PATCH v2 1/8] landlock: Fix non-TCP sockets restriction

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20241204.xoog3Quei4ta@digikod.net>
Date: Wed, 4 Dec 2024 20:30:41 +0100
From: Mickaël Salaün <mic@...ikod.net>
To: Mikhail Ivanov <ivanov.mikhail1@...wei-partners.com>
Cc: gnoack@...gle.com, willemdebruijn.kernel@...il.com, matthieu@...fet.re, 
	linux-security-module@...r.kernel.org, netdev@...r.kernel.org, netfilter-devel@...r.kernel.org, 
	yusongping@...wei.com, artem.kuzin@...wei.com, konstantin.meskhidze@...wei.com
Subject: Re: [RFC PATCH v2 1/8] landlock: Fix non-TCP sockets restriction

On Thu, Oct 17, 2024 at 07:04:47PM +0800, Mikhail Ivanov wrote:
> Do not check TCP access right if socket protocol is not IPPROTO_TCP.
> LANDLOCK_ACCESS_NET_BIND_TCP and LANDLOCK_ACCESS_NET_CONNECT_TCP
> should not restrict bind(2) and connect(2) for non-TCP protocols
> (SCTP, MPTCP, SMC).
> 
> sk_is_tcp() is used for this to check address family of the socket
> before doing INET-specific address length validation. This is required
> for error consistency.
> 
> Closes: https://github.com/landlock-lsm/linux/issues/40
> Fixes: fff69fb03dde ("landlock: Support network rules with TCP bind and connect")
> Signed-off-by: Mikhail Ivanov <ivanov.mikhail1@...wei-partners.com>
> ---
> 
> Changes since v1:
> * Validate socket family (=INET{,6}) before any other checks
>   with sk_is_tcp().
> ---
>  security/landlock/net.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/security/landlock/net.c b/security/landlock/net.c
> index fdc1bb0a9c5d..1e80782ba239 100644
> --- a/security/landlock/net.c
> +++ b/security/landlock/net.c
> @@ -66,8 +66,8 @@ static int current_check_access_socket(struct socket *const sock,
>  	if (WARN_ON_ONCE(dom->num_layers < 1))
>  		return -EACCES;
>  
> -	/* Checks if it's a (potential) TCP socket. */
> -	if (sock->type != SOCK_STREAM)
> +	/* Do not restrict non-TCP sockets. */

You can remove this comment because the following check is explicit.

> +	if (!sk_is_tcp(sock->sk))
>  		return 0;
>  
>  	/* Checks for minimal header length to safely read sa_family. */
> -- 
> 2.34.1
> 
>