* [PATCH v4] media:exynos4-is: Fix a use after free in isp_video_release
@ 2021-05-09 8:12 Lv Yunlong
0 siblings, 0 replies; only message in thread
From: Lv Yunlong @ 2021-05-09 8:12 UTC (permalink / raw)
To: s.nawrocki, mchehab, krzk
Cc: linux-media, linux-arm-kernel, linux-samsung-soc, linux-kernel,
Lv Yunlong
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 uses a variable 'is_singular_file' to avoid the uaf.
v3: https://lore.kernel.org/patchwork/patch/1419058/
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 | 7 +++++--
1 file changed, 5 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..3335fec509cb 100644
--- a/drivers/media/platform/exynos4-is/fimc-isp-video.c
+++ b/drivers/media/platform/exynos4-is/fimc-isp-video.c
@@ -306,17 +306,20 @@ 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);
- 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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