CVE-2021-46974
kernel: bpf: Fix masking negation logic upon negative dst register
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · February 27, 2024
Updated · August 5, 2026
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.
Statement
No Red Hat Products are affected by this vulnerability.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 2.3CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:L
CWE-20 · Improper Input Validation