Hi Paolo, On 26/11/2020 15:17, Paolo Abeni wrote:
If an msk listener receives an MPJ carrying an invalid token, it will zero the request socket msk entry. That should later cause fallback and subflow reset - as per RFC - at subflow_syn_recv_sock() time due to failing hmac validation.Since commit 4cf8b7e48a09 ("subflow: introduce and use mptcp_can_accept_new_subflow()"), we unconditionally dereference - in mptcp_can_accept_new_subflow - the subflow request msk before performing hmac validation. In the above scenario we hit a NULL ptr dereference. Address the issue doing the hmac validation earlier. Fixes: 4cf8b7e48a09 ("subflow: introduce and use mptcp_can_accept_new_subflow()") Tested-by: Davide Caratti <dcara...@redhat.com> Signed-off-by: Paolo Abeni <pab...@redhat.com>
Good catch! Thank you for the patch! Reviewed-by: Matthieu Baerts <matthieu.bae...@tessares.net> Cheers, Matt -- Tessares | Belgium | Hybrid Access Solutions www.tessares.net
