drm/exynos: vidi: use priv->vidi_dev for ctx lookup in vidi_connection_ioctl()

Overview

In the Linux kernel, the following vulnerability has been resolved:

drm/exynos: vidi: use priv->vidi_dev for ctx lookup in vidi_connection_ioctl()

vidi_connection_ioctl() retrieves the driver_data from drm_dev->dev to obtain a struct vidi_context pointer. However, drm_dev->dev is the exynos-drm master device, and the driver_data contained therein is not the vidi component device, but a completely different device.

This can lead to various bugs, ranging from null pointer dereferences and garbage value accesses to, in unlucky cases, out-of-bounds errors, use-after-free errors, and more.

To resolve this issue, we need to store/delete the vidi device pointer in exynos_drm_private->vidi_dev during bind/unbind, and then read this exynos_drm_private->vidi_dev within ioctl() to obtain the correct struct vidi_context pointer.

Affected

• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < 2987642c5213508c6c9e718324c0d5289a92c474
• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < 65d1213baffa363f2eb1117b1dc7acc573b890f8
• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < 875fa28690e93ed5296c31d3344556c6bb867234
• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < 21ca24ba51a2c28bcc4df9d7e5a40b0eb66ab76d
• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < e1aed617eb80b49eac2f8c7bb7a0990f641dd59b
• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < b5fc86d753dd4c281a943b92f0eef02d31af03d7
• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < a540f767642f75240a6c35f6a65b69e44cfcea9d
• Linux >= cf67cc9a29ac19c98bc4fa0e6d14b0c1f592d322 < d3968a0d85b211e197f2f4f06268a7031079e0d0
• Linux 4.3

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.