From: John Fastabend <john.fastabend@gmail.com>
To: Jann Horn <jannh@google.com>, Boris Pismenny <borisp@nvidia.com>,
John Fastabend <john.fastabend@gmail.com>,
Jakub Kicinski <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>
Cc: David Howells <dhowells@redhat.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] tls: fix NULL deref on tls_sw_splice_eof() with empty record
Date: Sun, 26 Nov 2023 15:56:46 -0800 [thread overview]
Message-ID: <6563db3e1d1ef_68d9b208cf@john.notmuch> (raw)
In-Reply-To: <CAG48ez3dn7CAfTmfziBUd_aFfcM1LOYsUuYrKykZAvTv=AAodg@mail.gmail.com>
Jann Horn wrote:
> On Wed, Nov 22, 2023 at 10:44 PM Jann Horn <jannh@google.com> wrote:
> > syzkaller discovered that if tls_sw_splice_eof() is executed as part of
> > sendfile() when the plaintext/ciphertext sk_msg are empty, the send path
> > gets confused because the empty ciphertext buffer does not have enough
> > space for the encryption overhead. This causes tls_push_record() to go on
> > the `split = true` path (which is only supposed to be used when interacting
> > with an attached BPF program), and then get further confused and hit the
> > tls_merge_open_record() path, which then assumes that there must be at
> > least one populated buffer element, leading to a NULL deref.
>
> Ah, and in case you're looking for the corresponding syzkaller report,
> you can find that at
> <https://lore.kernel.org/all/000000000000347a250608e8a4d1@google.com/T/>.
I'm a bit slow, but looks good to me as well. Thanks a lot.
Acked-by: John Fastabend <john.fastabend@gmail.com>
next prev parent reply other threads:[~2023-11-26 23:56 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-22 21:44 [PATCH net] tls: fix NULL deref on tls_sw_splice_eof() with empty record Jann Horn
2023-11-22 21:58 ` Jann Horn
2023-11-26 23:56 ` John Fastabend [this message]
2023-11-23 17:00 ` patchwork-bot+netdevbpf
2023-11-27 9:04 ` David Howells
2023-11-27 13:10 ` Jann Horn
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