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Paolo Abeni authored
The RFC 8684 mandates that no-data DATA FIN packets should carry a DSS with 0 sequence number and data len equal to 1. Currently, on FIN retransmission we re-use the existing mapping; if the previous fin transmission was part of a partially acked data packet, we could end-up writing in the egress packet a non-compliant DSS. The above will be detected by a "Bad mapping" warning on the receiver side. This change addresses the issue explicitly checking for 0 len packet when adding the DATA_FIN option. Fixes: 6d0060f6 ("mptcp: Write MPTCP DSS headers to outgoing data packets") Reported-by: syzbot+42a07faa5923cfaeb9c9@syzkaller.appspotmail.com Tested-by:
Christoph Paasch <cpaasch@apple.com> Reviewed-by:
Christoph Paasch <cpaasch@apple.com> Reviewed-by:
Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by:
Paolo Abeni <pabeni@redhat.com> Signed-off-by:
David S. Miller <davem@davemloft.net>
9c29e361