CVE-2021-46974

bpf: Fix masking negation logic upon negative dst register

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix masking negation logic upon negative dst register The negation logic for the case where the off_reg is sitting in the dst register is not correct given then we cannot just invert the add to a sub or vice versa. As a fix, perform the final bitwise and-op unconditionally into AX from the off_reg, then move the pointer from the src to dst and finally use AX as the source for the original pointer arithmetic operation such that the inversion yields a correct result. The single non-AX mov in between is possible given constant blinding is retaining it as it's not an immediate based operation.

5.5
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.01%
Affected: Linux Linux
Affected: Linux Linux
Published at:
Updated at:

References

Frequently Asked Questions

What is the severity of CVE-2021-46974?
CVE-2021-46974 has been scored as a medium severity vulnerability.
How to fix CVE-2021-46974?
To fix CVE-2021-46974, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2021-46974 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2021-46974 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2021-46974?
CVE-2021-46974 affects Linux Linux, Linux Linux.
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