Re: [PATCH 1/1] Smack: Assign smack_known_web as default smk_in label for kernel thread's socket

[Casey Schaufler <casey@schaufler-ca.com>]

On 1/22/2015 6:40 AM, Marcin Lis wrote:
> This change fixes the bug associated with sockets owned by kernel threads. These
> sockets, created usually by network devices' drivers tasks, received smk_in
> label from the task that created them - the "floor" label in the most cases. The
> result was that they were not able to receive data packets because of missing
> smack rules. The main reason of the access deny is that the socket smk_in label
> is placed as the object during smk check, kernel thread's capabilities are
> omitted.
>
> Signed-off-by: Marcin Lis <m.lis@samsung.com>

Applied to git://git.gitorious.org/smack-next/kernel.git#smack-for-4.1

> ---
>  security/smack/smack_lsm.c |   15 ++++++++++++++-
>  1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index a688f7b..535a06a 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -2452,7 +2452,20 @@ static int smack_inode_setsecurity(struct inode *inode, const char *name,
>  static int smack_socket_post_create(struct socket *sock, int family,
>  				    int type, int protocol, int kern)
>  {
> -	if (family != PF_INET || sock->sk == NULL)
> +	struct socket_smack *ssp;
> +
> +	if (sock->sk == NULL)
> +		return 0;
> +
> +	/*
> +	 * Sockets created by kernel threads receive web label.
> +	 */
> +	if (unlikely(current->flags & PF_KTHREAD)) {
> +		ssp = sock->sk->sk_security;
> +		ssp->smk_in = &smack_known_web;
> +	}
> +
> +	if (family != PF_INET)
>  		return 0;
>  	/*
>  	 * Set the outbound netlbl.