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

commit d4c98c077c7fb2dfdece7d605e694b5ea2665085 upstream.

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: Jeongjun Park <aha310510@gmail.com>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jeongjun Park 2026-01-19 17:25:52 +09:00 committed by Greg Kroah-Hartman
parent b5fc86d753
commit 4949e32387
1 changed files with 18 additions and 4 deletions
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22
drivers/gpu/drm/exynos/exynos_drm_vidi.c
View File

@ -262,13 +262,27 @@ 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;