From: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
To: s.nawrocki@samsung.com, mchehab@kernel.org, krzk@kernel.org
Cc: linux-media@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org,
Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Subject: [PATCH v3] media:exynos4-is: Fix a use after free in isp_video_release
Date: Tue, 27 Apr 2021 06:27:34 -0700 [thread overview]
Message-ID: <20210427132734.5212-1-lyl2019@mail.ustc.edu.cn> (raw)
In isp_video_release, file->private_data is freed via
_vb2_fop_release()->v4l2_fh_release(). But the freed
file->private_data is still used in v4l2_fh_is_singular_file()
->v4l2_fh_is_singular(file->private_data), which is a use
after free bug.
My patch sets file->private_data to NULL after _vb2_fop_release()
to avoid the use after free, and uses a variable 'is_singular_file'
to keep the original function unchanged.
Fixes: 34947b8aebe3f ("[media] exynos4-is: Add the FIMC-IS ISP capture DMA driver")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
---
drivers/media/platform/exynos4-is/fimc-isp-video.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/media/platform/exynos4-is/fimc-isp-video.c b/drivers/media/platform/exynos4-is/fimc-isp-video.c
index 612b9872afc8..c07dcb0bccc2 100644
--- a/drivers/media/platform/exynos4-is/fimc-isp-video.c
+++ b/drivers/media/platform/exynos4-is/fimc-isp-video.c
@@ -306,17 +306,21 @@ static int isp_video_release(struct file *file)
struct fimc_is_video *ivc = &isp->video_capture;
struct media_entity *entity = &ivc->ve.vdev.entity;
struct media_device *mdev = entity->graph_obj.mdev;
+ bool is_singular_file;
mutex_lock(&isp->video_lock);
- if (v4l2_fh_is_singular_file(file) && ivc->streaming) {
+ is_singular_file = v4l2_fh_is_singular_file(file);
+
+ if (is_singular_file && ivc->streaming) {
media_pipeline_stop(entity);
ivc->streaming = 0;
}
_vb2_fop_release(file, NULL);
+ file->private_data = NULL;
- if (v4l2_fh_is_singular_file(file)) {
+ if (is_singular_file) {
fimc_pipeline_call(&ivc->ve, close);
mutex_lock(&mdev->graph_mutex);
--
2.25.1
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next reply other threads:[~2021-04-27 13:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210427132754eucas1p21042e4e176135e7b3f7b540dc9aadfbb@eucas1p2.samsung.com>
2021-04-27 13:27 ` Lv Yunlong [this message]
2021-04-27 13:48 ` [PATCH v3] media:exynos4-is: Fix a use after free in isp_video_release Sylwester Nawrocki
2021-05-05 9:31 ` Hans Verkuil
2021-05-06 7:19 ` lyl2019
2021-05-06 7:23 ` Hans Verkuil
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