CVE-2021-47653

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

media: davinci: vpif: fix use-after-free on driver unbind

The driver allocates and registers two platform device structures during probe, but the devices were never deregistered on driver unbind.

This results in a use-after-free on driver unbind as the device structures were allocated using devres and would be freed by driver core when remove() returns.

Fix this by adding the missing deregistration calls to the remove() callback and failing probe on registration errors.

Note that the platform device structures must be freed using a proper release callback to avoid leaking associated resources like device names.

Weakness

The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.

Affected Software

Potential Mitigations

References

• https://git.kernel.org/stable/c/43acb728bbc40169d2e2425e84a80068270974be
• https://git.kernel.org/stable/c/6512c3c39cb6b573b791ce45365818a38b76afbe
• https://git.kernel.org/stable/c/9ffc602e14d7b9f7e7cb2f67e18dfef9ef8af676
• https://git.kernel.org/stable/c/b5a3bb7f6f164eb6ee74ef4898dcd019b2063448