drm/amd/display: Avoid HDCP over-read and corruption

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Avoid HDCP over-read and corruption Instead of reading the desired 5 bytes of the actual target field, the code was reading 8. This could result in a corrupted value if the trailing 3 bytes were non-zero, so instead use an appropriately sized and zero-initialized bounce buffer, and read only 5 bytes before casting to u64.

References

• https://git.kernel.org/stable/c/c5b518f4b98dbb2bc31b6a55e6aaa1e0e2948f2e
• https://git.kernel.org/stable/c/44c7c901cb368a9f2493748f213b247b5872639f
• https://git.kernel.org/stable/c/3b2b93a485fb7a970bc8b5daef16f4cf579d172f
• https://git.kernel.org/stable/c/06888d571b513cbfc0b41949948def6cb81021b2