Received-SPF: pass (google.com: domain of linux-kernel+bounces-156583-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.199.223 as permitted sender) client-ip=147.75.199.223;
Message-ID: <40e817d3-3a7a-4da5-9237-12915357e011@linaro.org>
Date: Wed, 24 Apr 2024 09:56:59 +0100
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] media: venus: fix use after free in vdec_close
Content-Language: en-US
To: Dikshita Agarwal <quic_dikshita@quicinc.com>,
 Stanimir Varbanov <stanimir.k.varbanov@gmail.com>,
 Vikash Garodia <quic_vgarodia@quicinc.com>,
 Bjorn Andersson <andersson@kernel.org>,
 Konrad Dybcio <konrad.dybcio@linaro.org>,
 Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org,
 linux-kernel@vger.kernel.org
References: <1713943070-24085-1-git-send-email-quic_dikshita@quicinc.com>
From: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
In-Reply-To: <1713943070-24085-1-git-send-email-quic_dikshita@quicinc.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit

On 24/04/2024 08:17, Dikshita Agarwal wrote:
> There appears to be a possible use after free with vdec_close().
> The firmware will add buffer release work to the work queue through
> HFI callbacks as a normal part of decoding. Randomly closing the
> decoder device from userspace during normal decoding can incur
> a read after free for inst.
> 
> Fix it by cancelling the work in vdec_close.
> 
> Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
> ---
>   drivers/media/platform/qcom/venus/vdec.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/media/platform/qcom/venus/vdec.c b/drivers/media/platform/qcom/venus/vdec.c
> index 29130a9..56f8a25 100644
> --- a/drivers/media/platform/qcom/venus/vdec.c
> +++ b/drivers/media/platform/qcom/venus/vdec.c
> @@ -1747,6 +1747,7 @@ static int vdec_close(struct file *file)
>   
>   	vdec_pm_get(inst);
>   
> +	cancel_work_sync(&inst->delayed_process_work);
>   	v4l2_m2m_ctx_release(inst->m2m_ctx);
>   	v4l2_m2m_release(inst->m2m_dev);
>   	vdec_ctrl_deinit(inst);

Needs a Fixes tag

---
bod