On Fri, Jun 3, 2016 at 12:24 PM, Eric Dumazet <eric.duma...@gmail.com> wrote: > On Fri, 2016-06-03 at 11:45 -0400, Neal Cardwell wrote: >> But I would also vote to tighten up the proposed logic slightly, and >> only check the seq of the incoming RST against the right edge of the >> *right-most* SACK block. That is, the code could loop through the >> tp->selective_acks to find the right-most of the right edges of the >> SACK blocks (the end_seq that has no other end_seq after() it). AFAICT >> it makes sense to expect that a legitimate incoming RST might match >> rcv_nxt, or might match the right-most edge of the right-most SACK. >> But allowing a RST to match a sequence of some SACK in the middle of >> the sequence range would seem to only increase the attack surface for >> RST attacks. > > Well, the most recent info would be in [0], no need to iterate, right ? > > So only look at the first sack block in the array, even if we have 3 or > 4 blocks there.
Yes, good point. It should only need to check the first SACK block in the selective_acks array. neal
