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

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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>
This commit is contained in:
Jeongjun Park 2026-01-19 17:25:52 +09:00 committed by Inki Dae
parent d3968a0d85
commit d4c98c077c
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1 changed files with 18 additions and 4 deletions
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22
drivers/gpu/drm/exynos/exynos_drm_vidi.c
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@ -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;