Re: [PATCH] LSM hooks for audit

On Wed, 2004-09-15 at 15:31, Serge E. Hallyn wrote: > > Sorry, I wasn't thinking in my initial response. These operations are > > exported via netlink, which is async, right? Hence, permission checks > > I was wondering about that. Based on the original code I assumed that > it was synchronous. > > Taking a second look at net/netlink, I guess not. > > Is there any reason why we can't find the task belonging to > NETLINK_CREDS(skb)->pid and send that along to the security_* hooks? Race conditions. Untrusted sender fires off a netlink message to set some value, then immediately exec's a privilege-changing program so that when the receiver evaluates the task's credentials, the task is running privileged. I think you either have to do all of your mediation at netlink_send time (as in the SELinux code) or get a security field into netlink_skb_parms (but then you have lifecycle management issues, which seems difficult to separate from having a general security field in the sk_buff itself).