From 01fe904c9afd26e79c1f73aa0ca2e3d785e5e319 Mon Sep 17 00:00:00 2001 From: Lv Yunlong Date: Sun, 9 May 2021 10:12:31 +0200 Subject: [PATCH] media: exynos4-is: Fix a use after free in isp_video_release 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 Signed-off-by: Hans Verkuil Signed-off-by: Mauro Carvalho Chehab --- 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 8d9dc597deaa..83688a7982f7 100644 --- a/drivers/media/platform/exynos4-is/fimc-isp-video.c +++ b/drivers/media/platform/exynos4-is/fimc-isp-video.c @@ -305,17 +305,20 @@ 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); -- 2.11.0