On Wed, 2016-09-28 at 10:56 -0400, Aaron Conole wrote:
> Eric Dumazet <eric.duma...@gmail.com> writes:
>
> > On Wed, 2016-09-28 at 09:12 -0400, Aaron Conole wrote:
> >> It's possible for nf_hook_entry_head to return NULL. If two
> >> nf_unregister_net_hook calls happen simultaneously with a single hook
> >> entry in the list, both will enter the nf_hook_mutex critical section.
> >> The first will successfully delete the head, but the second will see
> >> this NULL pointer and attempt to dereference.
> >>
> >> This fix ensures that no null pointer dereference could occur when such
> >> a condition happens.
> >>
> >> Signed-off-by: Aaron Conole <acon...@bytheb.org>
> >> ---
> >> net/netfilter/core.c | 2 +-
> >> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>
> >> diff --git a/net/netfilter/core.c b/net/netfilter/core.c
> >> index 360c63d..e58e420 100644
> >> --- a/net/netfilter/core.c
> >> +++ b/net/netfilter/core.c
> >> @@ -160,7 +160,7 @@ void nf_unregister_net_hook(struct net *net, const
> >> struct nf_hook_ops *reg)
> >>
> >> mutex_lock(&nf_hook_mutex);
> >> hooks_entry = nf_hook_entry_head(net, reg);
> >> - if (hooks_entry->orig_ops == reg) {
> >> + if (hooks_entry && hooks_entry->orig_ops == reg) {
> >> nf_set_hooks_head(net, reg,
> >> nf_entry_dereference(hooks_entry->next));
> >> goto unlock;
> >
> > When was the bug added exactly ?
>
> Sunday, on the nf-next tree.
>
> > For all bug fixes, you need to add a Fixes: tag.
> >
> > Like :
> >
> > Fixes: e3b37f11e6e4 ("netfilter: replace list_head with single linked list")
>
> I would but it's in nf-next tree, and I'm not sure how pulls go. If
> they are done via patch imports, then the sha sums will be wrong and the
> commit message will be misleading. If the sums are preserved, then I
> can resubmit with this information.
>
I gave the (12 digits) sha-1 as present in David Miller net-next tree.
https://git.kernel.org/cgit/linux/kernel/git/davem/net-next.git/commit/?id=e3b37f11e6e4e6b6f02cc762f182ce233d2c1c9d
This wont change, because David never rebases his tree under normal
operations.
Thanks.
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