netdev - Re: BPF: ETLS: RECV FLOW

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Date:   Sun, 04 Aug 2019 20:43:49 -0700
From:   John Fastabend <john.fastabend@...il.com>
To:     Shridhar Venkatraman <shridhar@...mtree.com>,
        netdev@...r.kernel.org
Subject: Re: BPF: ETLS: RECV FLOW

Shridhar Venkatraman wrote:
> Hi,
> 
> The eTLS work has BPF integration which is great.
> However there is one spot where access to the clear text is not available.

Guessing eTLS is a typo for KTLS.

> 
> From kernel 4.20 - receiver BPF support added for KTLS.
> 
> a. receiver BPF is applied on encrypted message
> b. after applying BPF, message is decrypted
> c. BPF run logic on the decrypted plain message   - can we add this support ?
> d. then copy the decrypted message back to userspace.
> 
> code flow reference: tls receive message call flow:
> --------------------------------------------------------------
> 
> tls_sw_recvmsg
>   __tcp_bpf_recvmsg [ bpf exec function called on encrypted message ]
>   decrypt_skb_update
>   decrypt_internal
>   BPF_PROG_RUN on decrypted plain message - can we add this support ?
>   skb_copy_datagram_msg [ decrypted message copied back to userspace ]

Yes I'm aware of this I'll push patches this release cycle. At least that
is the plan. I have some internal patches I've been running for some time
but need to clean up an edge case. Hopefully should get to it this week
after fixing up a couple bugs first.

> 
> Thanks
> ps: I sent this to the bpf list as I don't know which one it should go to

sending to bpf list and CC netdev would work or just BPF list.

.John