Re: [TOMOYO #5 18/18] LSM expansion for TOMOYO Linux.

[Paul Moore <paul.moore@hp.com>]

On Saturday 17 November 2007 11:00:20 pm Tetsuo Handa wrote:
> Hello.

Hello.

> Paul Moore wrote:
> > Okay, well if that is the case I think you are going to have another
> > problem in that you could end up throwing away skbs that haven't been
> > through your security_post_recv_datagram() hook because you _always_
> > throw away the result of the second skb_peek().  Once again, if I'm wrong
> > please correct me.
>
> I didn't understand what's wrong with throwing away the result of
> the second skb_peek().

My concern is that you stated earlier that you needed to do the second 
skb_peek() because the first skb may have been removed from the socket queue 
while your LSM was making an access decision in 
security_post_recv_datagram().  If that is the case then the second call to 
skb_peek() will return a different skb then the one you passed to 
security_post_recv_datagram().  This is significant because you always throw 
away this second skb without first consulting the LSM via 
security_post_recv_datagram().

-- 
paul moore
linux security @ hp