On Mon, Oct 02, 2017 at 12:20:51PM -0700, Eric Dumazet wrote:
> From: Eric Dumazet <eduma...@google.com>
>
> Starting from linux-4.4, 3WHS no longer takes the listener lock.
>
> Since this time, we might hit a use-after-free in sk_filter_charge(),
> if the filter we got in the memcpy() of the listener content
> just happened to be replaced by a thread changing listener BPF filter.
>
> To fix this, we need to make sure the filter refcount is not already
> zero before incrementing it again.
>
> Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
> Signed-off-by: Eric Dumazet <eduma...@google.com>
Thanks for the fix!
Acked-by: Alexei Starovoitov <a...@kernel.org>
