From: David Miller <davem@davemloft.net>
To: jakub.kicinski@netronome.com
Cc: netdev@vger.kernel.org, oss-drivers@netronome.com,
borisp@mellanox.com, aviadye@mellanox.com,
john.fastabend@gmail.com, daniel@iogearbox.net,
syzbot+f8495bff23a879a6d0bd@syzkaller.appspotmail.com,
syzbot+6f50c99e8f6194bf363f@syzkaller.appspotmail.com,
ebiggers@kernel.org, herbert@gondor.apana.org.au,
glider@google.com, linux-crypto@vger.kernel.org
Subject: Re: [PATCH net v2] net/tls: fix sk_msg trim on fallback to copy mode
Date: Tue, 05 Nov 2019 18:08:29 -0800 (PST) [thread overview]
Message-ID: <20191105.180829.228337395055155315.davem@davemloft.net> (raw)
In-Reply-To: <20191104233657.21054-1-jakub.kicinski@netronome.com>
From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Mon, 4 Nov 2019 15:36:57 -0800
> sk_msg_trim() tries to only update curr pointer if it falls into
> the trimmed region. The logic, however, does not take into the
> account pointer wrapping that sk_msg_iter_var_prev() does nor
> (as John points out) the fact that msg->sg is a ring buffer.
>
> This means that when the message was trimmed completely, the new
> curr pointer would have the value of MAX_MSG_FRAGS - 1, which is
> neither smaller than any other value, nor would it actually be
> correct.
>
> Special case the trimming to 0 length a little bit and rework
> the comparison between curr and end to take into account wrapping.
>
> This bug caused the TLS code to not copy all of the message, if
> zero copy filled in fewer sg entries than memcopy would need.
>
> Big thanks to Alexander Potapenko for the non-KMSAN reproducer.
>
> v2:
> - take into account that msg->sg is a ring buffer (John).
>
> Link: https://lore.kernel.org/netdev/20191030160542.30295-1-jakub.kicinski@netronome.com/ (v1)
>
> Fixes: d829e9c4112b ("tls: convert to generic sk_msg interface")
> Reported-by: syzbot+f8495bff23a879a6d0bd@syzkaller.appspotmail.com
> Reported-by: syzbot+6f50c99e8f6194bf363f@syzkaller.appspotmail.com
> Co-developed-by: John Fastabend <john.fastabend@gmail.com>
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Applied and queued up for -stable, thanks Jakub.
prev parent reply other threads:[~2019-11-06 2:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-04 23:36 [PATCH net v2] net/tls: fix sk_msg trim on fallback to copy mode Jakub Kicinski
2019-11-05 14:48 ` John Fastabend
2019-11-06 2:08 ` David Miller [this message]
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