Memory Leak Affecting kernel-cross-headers package, versions *

Note: Versions mentioned in the description apply only to the upstream kernel-cross-headers package and not the kernel-cross-headers package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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

media: v4l2-core: explicitly clear ioctl input data

As seen from a recent syzbot bug report, mistakes in the compat ioctl implementation can lead to uninitialized kernel stack data getting used as input for driver ioctl handlers.

The reported bug is now fixed, but it's possible that other related bugs are still present or get added in the future. As the drivers need to check user input already, the possible impact is fairly low, but it might still cause an information leak.

To be on the safe side, always clear the entire ioctl buffer before calling the conversion handler functions that are meant to initialize them.

• https://access.redhat.com/security/cve/CVE-2021-47339
• https://git.kernel.org/stable/c/7b53cca764f9b291b7907fcd39d9e66ad728ee0b
• https://git.kernel.org/stable/c/bfb48b54db25c3b4ef4bef5e0691464ebc4aa335
• https://git.kernel.org/stable/c/dc02c0b2bd6096f2f3ce63e1fc317aeda05f74d8