Re: [PATCH 16/20] audit: allow GET, SET, USER MSG operations in audit namespace

["Serge E. Hallyn" <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>]

Quoting Gao feng (gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org):
> 1, remove the permission check of pid namespace. it's no reason
>    to deny un-init pid namespace to operate audit subsystem.
> 
> 2, only allow init user namespace and init audit namespace to
>    operate list/add/del rule, tty set, trim, make equiv operations.
> 
> 3, allow audit namespace to get/set audit configuration, send
>    userspace audit message.
> 
> Signed-off-by: Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public.gmane.org>
> ---
>  kernel/audit.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/kernel/audit.c b/kernel/audit.c
> index 095f54d..c4d4291 100644
> --- a/kernel/audit.c
> +++ b/kernel/audit.c
> @@ -573,11 +573,7 @@ out:
>  static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
>  {
>  	int err = 0;
> -
> -	/* Only support the initial namespaces for now. */
> -	if ((current_user_ns() != &init_user_ns) ||
> -	    (task_active_pid_ns(current) != &init_pid_ns))
> -		return -EPERM;
> +	struct audit_namespace *ns = current->nsproxy->audit_ns;
>  
>  	switch (msg_type) {
>  	case AUDIT_LIST:
> @@ -586,6 +582,7 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
>  		return -EOPNOTSUPP;
>  	case AUDIT_GET:
>  	case AUDIT_SET:
> +		break;

So, these AUDIT_SET and AUDIT_GET go from requiring CAP_AUDIT_CONTROL
to not needing any privs at all?

>  	case AUDIT_LIST_RULES:
>  	case AUDIT_ADD_RULE:
>  	case AUDIT_DEL_RULE:
> @@ -594,13 +591,15 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type)
>  	case AUDIT_TTY_SET:
>  	case AUDIT_TRIM:
>  	case AUDIT_MAKE_EQUIV:
> -		if (!capable(CAP_AUDIT_CONTROL))
> +		if ((current_user_ns() != &init_user_ns) ||
> +		    (ns != &init_audit_ns) ||
> +		    !capable(CAP_AUDIT_CONTROL))
>  			err = -EPERM;
>  		break;
>  	case AUDIT_USER:
>  	case AUDIT_FIRST_USER_MSG ... AUDIT_LAST_USER_MSG:
>  	case AUDIT_FIRST_USER_MSG2 ... AUDIT_LAST_USER_MSG2:
> -		if (!capable(CAP_AUDIT_WRITE))
> +		if (!ns_capable(ns->user_ns, CAP_AUDIT_WRITE))
>  			err = -EPERM;
>  		break;
>  	default:  /* bad msg */
> -- 
> 1.8.3.1
> 
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