Messages in this thread | | | Date | Tue, 22 Apr 2014 21:30:05 -0400 | From | Richard Guy Briggs <> | Subject | Re: [PATCH 2/6] netlink: have netlink per-protocol bind function return an error code. |
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On 14/04/22, David Miller wrote: > From: Richard Guy Briggs <rgb@redhat.com> > Date: Fri, 18 Apr 2014 13:34:06 -0400 > > > @@ -1449,6 +1453,26 @@ static int netlink_bind(struct socket *sock, struct sockaddr *addr, > > if (!nladdr->nl_groups && (nlk->groups == NULL || !(u32)nlk->groups[0])) > > return 0; > > > > + if (nlk->netlink_bind && nladdr->nl_groups) { > > + int i; > > + > > + for (i = 0; i < nlk->ngroups; i++) { > > + int undo; > > + > > + if (!test_bit(i, (long unsigned int *)&nladdr->nl_groups)) > > + continue; > > + err = nlk->netlink_bind(i); > > + if (!err) > > + continue; > > + if (!nlk->portid) > > + netlink_remove(sk); > > + for (undo = 0; undo < i; undo++) > > + if (nlk->netlink_unbind) > > + nlk->netlink_unbind(undo); > > + return err; > > + } > > + } > > + > > It took me a while to figure out why you need to do the netlink_remove() in > the error path. > > I think it's really asking for trouble to allow the socket to have temporary > visibility if we end up signalling an error.
The risk seems small, but I agree it is sloppy.
> It seems safest if we only do the autobind/insert once we are absolutely > certain that the bind() will fully succeed. This means that you have to > do this bind validation loop before autobind/insert.
Ok, done. This revision ends up being a bit cleaner than the previous one because I've refactored out the unbind loop into netlink_unbind() due to it needing to be called if the netlink_insert/autobind() fails as well. In the factorization process I noticed that unrequested groups were being unnecessarily unbound. It also provoked assigning the var "groups" from "nladdr->nl_groups" making things easier to read.
> Please make this change and resubmit this series, thanks.
Compiled and tested. New patchset to follow.
- RGB
-- Richard Guy Briggs <rbriggs@redhat.com> Senior Software Engineer, Kernel Security, AMER ENG Base Operating Systems, Red Hat Remote, Ottawa, Canada Voice: +1.647.777.2635, Internal: (81) 32635, Alt: +1.613.693.0684x3545
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