Re: [PATCH] cifs: Fix problem with encrypted RDMA data read

From: David Howells
Date: Wed Nov 16 2022 - 02:01:35 EST


Stefan Metzmacher <metze@xxxxxxxxx> wrote:

> I'm not sure I understand why this would fix anything when encryption is
> enabled.
>
> Is the payload still be offloaded as plaintext? Otherwise we wouldn't have
> use_rdma_mr... So this rather looks like a fix for the non encrypted case.

The "inline"[*] PDUs are encrypted, but the direct RDMA data transmission is
not. I'm not sure if this is a bug in ksmbd. As I understand it, encrypting
and decrypting the directly transferred data would need to be done by the NIC,
not the cifs driver.

David

[*] I don't know the correct RDMA terminology for these things.