From: "Jonathan Lemon" <jlemon@flugsvamp.com>
To: "John Fastabend" <john.fastabend@gmail.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, ast@kernel.org,
daniel@iogearbox.net
Subject: Re: [bpf PATCH 6/9] bpf: sockmap/tls, tls_sw can create a plaintext buf > encrypt buf
Date: Thu, 09 Jan 2020 15:04:40 -0800 [thread overview]
Message-ID: <B265C993-B266-4CC7-B32A-C877667C545A@flugsvamp.com> (raw)
In-Reply-To: <157851813461.1732.9406594355094857662.stgit@ubuntu3-kvm2>
On 8 Jan 2020, at 13:15, John Fastabend wrote:
> It is possible to build a plaintext buffer using push helper that is larger
> than the allocated encrypt buffer. When this record is pushed to crypto
> layers this can result in a NULL pointer dereference because the crypto
> API expects the encrypt buffer is large enough to fit the plaintext
> buffer.
>
> To resolve catch the cases this can happen and split the buffer into two
> records to send individually. Unfortunately, there is still one case to
> handle where the split creates a zero sized buffer. In this case we merge
> the buffers and unmark the split. This happens when apply is zero and user
> pushed data beyond encrypt buffer. This fixes the original case as well
> because the split allocated an encrypt buffer larger than the plaintext
> buffer and the merge simply moves the pointers around so we now have
> a reference to the new (larger) encrypt buffer.
>
> Perhaps its not ideal but it seems the best solution for a fixes branch
> and avoids handling these two cases, (a) apply that needs split and (b)
> non apply case. The are edge cases anyways so optimizing them seems not
> necessary unless someone wants later in next branches.
>
> Fixes: d3b18ad31f93d ("tls: add bpf support to sk_msg handling")
> Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
next prev parent reply other threads:[~2020-01-09 23:11 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-08 21:13 [bpf PATCH 0/9] Fixes for sockmap/tls from more complex BPF progs John Fastabend
2020-01-08 21:14 ` [bpf PATCH 1/9] bpf: sockmap/tls, during free we may call tcp_bpf_unhash() in loop John Fastabend
2020-01-09 1:34 ` Song Liu
2020-01-08 21:14 ` [bpf PATCH 2/9] bpf: sockmap, ensure sock lock held during tear down John Fastabend
2020-01-09 17:10 ` Song Liu
2020-01-08 21:14 ` [bpf PATCH 3/9] bpf: sockmap/tls, push write_space updates through ulp updates John Fastabend
2020-01-09 10:33 ` Jakub Sitnicki
2020-01-09 21:22 ` John Fastabend
2020-01-10 13:40 ` Jakub Sitnicki
2020-01-08 21:14 ` [bpf PATCH 4/9] bpf: sockmap, skmsg helper overestimates push, pull, and pop bounds John Fastabend
2020-01-09 18:37 ` Song Liu
2020-01-08 21:15 ` [bpf PATCH 5/9] bpf: sockmap/tls, msg_push_data may leave end mark in place John Fastabend
2020-01-09 18:51 ` Song Liu
2020-01-08 21:15 ` [bpf PATCH 6/9] bpf: sockmap/tls, tls_sw can create a plaintext buf > encrypt buf John Fastabend
2020-01-09 23:04 ` Jonathan Lemon [this message]
2020-01-08 21:15 ` [bpf PATCH 7/9] bpf: sockmap/tls, skmsg can have wrapped skmsg that needs extra chaining John Fastabend
2020-01-09 23:13 ` Jonathan Lemon
2020-01-08 21:16 ` [bpf PATCH 8/9] bpf: sockmap/tls, tls_push_record can not handle zero length skmsg John Fastabend
2020-01-09 20:08 ` Song Liu
2020-01-09 21:25 ` John Fastabend
2020-01-10 23:20 ` John Fastabend
2020-01-08 21:16 ` [bpf PATCH 9/9] bpf: sockmap/tls, fix pop data with SK_DROP return code John Fastabend
2020-01-09 23:28 ` Jonathan Lemon
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