|| ||Eric Dumazet <erdnetdev-AT-gmail.com> |
|| ||Zhiyun Qian <zhiyunq-AT-umich.edu> |
|| ||Re: TCP sequence number inference attack on Linux |
|| ||Fri, 21 Dec 2012 16:01:21 -0800|
|| ||Article, Thread
On Fri, 2012-12-21 at 18:52 -0500, Zhiyun Qian wrote:
> It seems that it is not straightforward to simply move tcp_ack()
> before tcp_validate_incoming() as tcp_ack() currently assumes the tcp
> sequence number is already validated and it may adjust certain states
> purely depending on the ACK number. I guess the solution is to extract
> all safety checks out and put at the very beginning. The rest of the
> code in tcp_validate_incoming() and tcp_ack() may still need to
> perform the redundant checks since if some state changes are dependent
> on the sequence number or ACK number (e.g., window update).
> I'm willing to help on this. Perhaps I can draft an initial patch and
> you can help take a look before I submit it?
I began coding a serie of patches.
Part of the problem comes from a 'fast path' idea that was nice 20 years
ago but no longer a real killer these days.
So some tests are duplicated, others are not correctly done.
For example, the fast path misses the more complete tests done in
Its a big mess.
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