Messages in this thread | | | Subject | Re: [PATCH 6/6] protect cap_netlink_recv from user namespaces | From | Eric Paris <> | Date | Mon, 07 Nov 2011 14:35:10 -0500 |
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On Fri, 2011-11-04 at 22:24 +0000, Serge Hallyn wrote: > From: Serge E. Hallyn <serge.hallyn@canonical.com> > > cap_netlink_recv() was granting privilege if a capability is in > current_cap(), regardless of the user namespace. Fix that by > targeting the capability check against the user namespace which > owns the skb. > > Caller passes the user ns down because sock_net is static inline defined in > net/sock.h, which we'd rather not #include at the cap_netlink_recv function.
This is wrong at least in relation to audit. I don't know the other code well enough to know if I think it's ok there. Lets say I have (CAP_SYS_ADMIN | CAP_SETUID | CAP_SETGID) and I create a new task with CLONE_NEWNAME. This task then immediately does the needful to remove all audit rules (which supposedly requires CAP_AUDIT_CONTROL). That's going to succeed because the task is init in it's namespace, aka:
/* The creator of the user namespace has all caps. */ if (targ_ns != &init_user_ns && targ_ns->creator == cred->user) return 0;
But it just screwed with a global resource. aka audit. I don't know the meaning of these others, but it seems to me probably most or all of them should be against the init_user_ns, not the namespace the skb came from....
What am I missing?
-Eric
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