Unverified Commit d4c98c07 authored by Jeongjun Park's avatar Jeongjun Park Committed by Inki Dae
Browse files

drm/exynos: vidi: fix to avoid directly dereferencing user pointer 



In vidi_connection_ioctl(), vidi->edid(user pointer) is directly
dereferenced in the kernel.

This allows arbitrary kernel memory access from the user space, so instead
of directly accessing the user pointer in the kernel, we should modify it
to copy edid to kernel memory using copy_from_user() and use it.

Cc: <stable@vger.kernel.org>
Signed-off-by: default avatarJeongjun Park <aha310510@gmail.com>
Signed-off-by: default avatarInki Dae <inki.dae@samsung.com>
parent d3968a0d

drivers/gpu/drm/exynos/exynos_drm_vidi.c

+18 −4
Original line number Diff line number Diff line
@@ -252,13 +252,27 @@ int vidi_connection_ioctl(struct drm_device *drm_dev, void *data, 


	if (vidi->connection) {

		const struct drm_edid *drm_edid;

		const struct edid *raw_edid;

		const void __user *edid_userptr = u64_to_user_ptr(vidi->edid);

		void *edid_buf;

		struct edid hdr;

		size_t size;



		raw_edid = (const struct edid *)(unsigned long)vidi->edid;

		size = (raw_edid->extensions + 1) * EDID_LENGTH;

		if (copy_from_user(&hdr, edid_userptr, sizeof(hdr)))

			return -EFAULT;



		drm_edid = drm_edid_alloc(raw_edid, size);

		size = (hdr.extensions + 1) * EDID_LENGTH;



		edid_buf = kmalloc(size, GFP_KERNEL);

		if (!edid_buf)

			return -ENOMEM;



		if (copy_from_user(edid_buf, edid_userptr, size)) {

			kfree(edid_buf);

			return -EFAULT;

		}



		drm_edid = drm_edid_alloc(edid_buf, size);

		kfree(edid_buf);

		if (!drm_edid)

			return -ENOMEM;