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From: "Agarwal, Dikshita" <dikshita@qti.qualcomm.com>
To: 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>,
        Hans Verkuil <hans.verkuil@cisco.com>
Cc: "Bryan O'Donoghue" <bryan.odonoghue@linaro.org>,
        Stanimir Varbanov <stanimir.varbanov@linaro.org>,
        linux-media@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Dikshita Agarwal <quic_dikshita@quicinc.com>, stable@vger.kernel.org
Subject: [PATCH v2] media: venus: fix use after free in vdec_close
Date: Mon,  6 May 2024 11:11:50 +0530
Message-Id: <1714974110-19175-1-git-send-email-dikshita@qti.qualcomm.com>
Precedence: bulk

From: Dikshita Agarwal <quic_dikshita@quicinc.com>

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.

Cc: stable@vger.kernel.org
Fixes: af2c3834c ("media: venus: adding core part and helper functions")
Signed-off-by: Dikshita Agarwal <quic_dikshita@quicinc.com>
---
Changes since v1:
- Added fixes and stable tags

 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);
-- 
2.7.4