In the Linux kernel, the following vulnerability has been resolved:
staging: most: video: avoid double free on video register failure
comp_register_videodev() allocates a video_device with video_device_alloc() and releases it if video_register_device() fails.
This can double free the video_device when __video_register_device() reaches device_register() and that call fails:
video_register_device() -> __video_register_device() -> device_register() fails -> put_device(&vdev->dev) -> v4l2_device_release() -> vdev->release(vdev) -> video_device_release(vdev)
comp_register_videodev() -> video_device_release(mdev->vdev)
Use video_device_release_empty() while registering the device so that registration failure paths do not free mdev->vdev through vdev->release(). comp_register_videodev() then releases mdev->vdev exactly once on failure. Restore video_device_release() after successful registration so the registered device keeps its normal lifetime handling.
This issue was found by a static analysis tool I am developing.
References
- https://git.kernel.org/stable/c/009d58b73500d0b49f6ae3833f8afcb0ebd9ddbb
- https://git.kernel.org/stable/c/43078449ad6236d839e4d707954d2e36b10a6706
- https://git.kernel.org/stable/c/430ad4ea06a0767fb44a08e2212ceb3a996607ee
- https://git.kernel.org/stable/c/46ea51f5b2ee1a3b40c05b7c750cbc5cabe94062
- https://git.kernel.org/stable/c/4928096212b78262dbbeab3b3abf2352278ce22d
- https://git.kernel.org/stable/c/7cb1c5b32a2bfde961fff8d5204526b609bcb30a
- https://git.kernel.org/stable/c/7fc162453cfb7b8e93edb16287a84ba0130cac38
- https://git.kernel.org/stable/c/80ed79787da3311f76b4d71d0ce7ab992a9e134d