Date:   Fri, 24 Feb 2023 13:06:25 -0800
From:   Jakub Kicinski <kuba@kernel.org>
To:     Sabrina Dubroca <sd@queasysnail.net>
Cc:     Hangyu Hua <hbh25y@gmail.com>, Florian Westphal <fw@strlen.de>,
        borisp@nvidia.com, john.fastabend@gmail.com, davem@davemloft.net,
        edumazet@google.com, pabeni@redhat.com, davejwatson@fb.com,
        aviadye@mellanox.com, ilyal@mellanox.com, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] net: tls: fix possible race condition between
 do_tls_getsockopt_conf() and do_tls_setsockopt_conf()
Message-ID: <20230224130625.6b5261b4@kernel.org>
In-Reply-To: <Y/kck0/+NB+Akpoy@hog>
References: <20230224105811.27467-1-hbh25y@gmail.com>
        <20230224120606.GI26596@breakpoint.cc>
        <20230224105508.4892901f@kernel.org>
        <Y/kck0/+NB+Akpoy@hog>
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On Fri, 24 Feb 2023 21:22:43 +0100 Sabrina Dubroca wrote:
> > Right, the bug and the fix seem completely bogus.
> > Please make sure the bugs are real and the fixes you sent actually 
> > fix them.  
> 
> I suggested a change of locking in do_tls_getsockopt_conf this
> morning [1]. The issue reported last seemed valid, but this patch is not
> at all what I had in mind.
> [1] https://lore.kernel.org/all/Y/ht6gQL+u6fj3dG@hog/

Ack, I read the messages out of order, sorry.

> do_tls_setsockopt_conf fills crypto_info immediately from what
> userspace gives us (and clears it on exit in case of failure), which
> getsockopt could see since it's not locking the socket when it checks
> TLS_CRYPTO_INFO_READY. So getsockopt would progress up to the point it
> finally locks the socket, but if setsockopt failed, we could have
> cleared TLS_CRYPTO_INFO_READY and freed iv/rec_seq.

Makes sense. We should just take the socket lock around all of
do_tls_getsockopt(), then?