CVE-2021-46974

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description The issue is related to the Linux kernel's bpf (Berkeley Packet Filter) functionality, specifically with the masking negation logic when the off reg is in the dst register. The negation logic is not correct, and as a fix, a final bitwise and-op is performed unconditionally into AX from the off reg, then the pointer is moved from the src to dst, and finally AX is used as the source for the original pointer arithmetic operation. This ensures the inversion yields a correct result. The single non-AX mov in between is possible due to constant blinding retaining it as it's not an immediate based operation.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.