netdev - Re: various TLS bug fixes...

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Message-ID: <20190821155519.61d9feda@cakuba.netronome.com>
Date:   Wed, 21 Aug 2019 15:55:19 -0700
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     John Fastabend <john.fastabend@...il.com>
Cc:     David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: various TLS bug fixes...

On Wed, 21 Aug 2019 11:03:46 -0700, Jakub Kicinski wrote:
> On Tue, 20 Aug 2019 23:51:12 -0700, Jakub Kicinski wrote:
> > > If you have more details I can also spend some cycles looking into it.    
> > 
> > Awesome, I'll let you know what the details are as soon as I get them.  
> 
> Just a quick update on that.
> 
> The test case is nginx running with ktls offload.
> 
> The client (hurl or openssl client) requests a file of ~2M, but only
> 44K ever gets across (not even sure which side sees an error at this
> point, outputs are pretty quiet).

I had a look, it's this:

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 6848a8196711..8a05e4bf1c58 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -370,7 +370,8 @@ int tls_sw_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)

        lock_sock(sk);

-       if (tls_complete_pending_work(sk, tls_ctx, msg->msg_flags, &timeo))
+       ret = tls_complete_pending_work(sk, tls_ctx, msg->msg_flags, &timeo);
+       if (ret)
                goto send_end;

        if (unlikely(msg->msg_controllen)) {

Which is commit 150085791afb ("net/tls: Fixed return value when
tls_complete_pending_work() fails"). 

I also tried to test what we described previously for sk_write_space
and it seems to work okay (although TBH I'm not sure my testing is 100%
here, I can't reliably trigger that race in the first place).