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prionPRIOn knowledge basePRION:CVE-2021-46974
HistoryFeb 27, 2024 - 7:04 p.m.

Spoofing

2024-02-2719:04:00
PRIOn knowledge base
www.prio-n.com
6
spoofing
linux
kernel
vulnerability
bpf
masking
negation

7.1 High

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

10.4%

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.

7.1 High

AI Score

Confidence

Low

0.0004 Low

EPSS

Percentile

10.4%