Re: [PATCH v3] tcp: verify the checksum of the first data segment in a new connection

On 6/14/18 5:05 PM, David Miller wrote:

From: Frank van der Linden <redacted>
Date: Tue, 12 Jun 2018 23:09:37 +0000

quoted

commit 079096f103fa ("tcp/dccp: install syn_recv requests into ehash
table") introduced an optimization for the handling of child sockets
created for a new TCP connection.

But this optimization passes any data associated with the last ACK of the
connection handshake up the stack without verifying its checksum, because it
calls tcp_child_process(), which in turn calls tcp_rcv_state_process()
directly.  These lower-level processing functions do not do any checksum
verification.

Insert a tcp_checksum_complete call in the TCP_NEW_SYN_RECEIVE path to
fix this.

Signed-off-by: Frank van der Linden <redacted>

Applied and queued up for -stable.

I know you mention the bug causing commit in your commit message,
but you should also still provide a proper Fixes: tag.  I took
care of it for you this time.

Thanks Dave, and thanks for reminding me of the Fixes: tag. Will add it
next time.

- Frank