From 4949e32387fe315b59ad5f422c9fc52836fbdd1e Mon Sep 17 00:00:00 2001 From: Jeongjun Park Date: Mon, 19 Jan 2026 17:25:52 +0900 Subject: [PATCH] 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: Signed-off-by: Jeongjun Park Signed-off-by: Inki Dae Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/exynos/exynos_drm_vidi.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/exynos/exynos_drm_vidi.c b/drivers/gpu/drm/exynos/exynos_drm_vidi.c index bf5ba5458917..37733f2ac0e7 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_vidi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_vidi.c @@ -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;