From: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
To: Vikash Garodia <quic_vgarodia@quicinc.com>,
Dikshita Agarwal <quic_dikshita@quicinc.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Stanimir Varbanov <stanimir.varbanov@linaro.org>,
Hans Verkuil <hans.verkuil@cisco.com>
Cc: linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org,
linux-kernel@vger.kernel.org,
Vedang Nagar <quic_vnagar@quicinc.com>
Subject: Re: [PATCH v3 1/2] media: venus: fix TOCTOU vulnerability when reading packets from shared memory
Date: Thu, 15 May 2025 13:47:12 +0100 [thread overview]
Message-ID: <bd704149-694f-4d89-90d9-a22307488743@linaro.org> (raw)
In-Reply-To: <b663539d-5ad6-399b-1e7b-0b8b9daca10d@quicinc.com>
On 15/05/2025 13:11, Vikash Garodia wrote:
>> But what if the "malicious" firmware only updated the data in the packet, not
>> the length - or another field we are not checking ?
> That does not cause any vulnerability. You can check and suggest if you see a
> vulnerability when the data outside length is an issue w.r.t vulnerability.
I don't believe you have identified a vulnerability here.
You read a length field, you check that length field against a MAX size.
Re-reading to see if the firmware wrote new bad data to the transmitted
packet in-memory is not a fix before or after the memcpy() because the
time you do that re-read is not fixed - locked wrt the freerunning firmware.
---
bod
next prev parent reply other threads:[~2025-05-15 12:47 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-14 13:38 [PATCH v3 0/2] venus driver fixes for vulnerabilities due to unexpected firmware payload Dikshita Agarwal
2025-05-14 13:38 ` [PATCH v3 1/2] media: venus: fix TOCTOU vulnerability when reading packets from shared memory Dikshita Agarwal
2025-05-15 9:17 ` Bryan O'Donoghue
2025-05-15 9:56 ` Vikash Garodia
2025-05-15 10:28 ` Bryan O'Donoghue
2025-05-15 12:11 ` Vikash Garodia
2025-05-15 12:47 ` Bryan O'Donoghue [this message]
2025-05-15 13:23 ` Vikash Garodia
2025-05-15 17:51 ` Bryan O'Donoghue
2025-05-15 18:25 ` Vikash Garodia
2025-05-16 10:11 ` Bryan O'Donoghue
2025-05-14 13:38 ` [PATCH v3 2/2] media: venus: Fix OOB read due to missing payload bound check Dikshita Agarwal
2025-05-17 21:41 ` Bryan O'Donoghue
2025-05-18 3:56 ` Vikash Garodia
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