CVE-2021-46974
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…
Does this matter?
Lower severity and a low EPSS score (0.25%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 5.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.25% probability · 16th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/0e2dfdc74a7f4036127356d42ea59388f153f42cPatch
- https://git.kernel.org/stable/c/2cfa537674cd1051a3b8111536d77d0558f33d5dPatch
- https://git.kernel.org/stable/c/4d542ddb88fb2f39bf7f14caa2902f3e8d06f6baPatch
- https://git.kernel.org/stable/c/53e0db429b37a32b8fc706d0d90eb4583ad13848Patch
- https://git.kernel.org/stable/c/6eba92a4d4be8feb4dc33976abac544fa99d6eccPatch
- https://git.kernel.org/stable/c/7cf64d8679ca1cb20cf57d6a88bfee79a0922a66Patch
- https://git.kernel.org/stable/c/b9b34ddbe2076ade359cd5ce7537d5ed019e9807Patch
- https://git.kernel.org/stable/c/0e2dfdc74a7f4036127356d42ea59388f153f42cPatch
- https://git.kernel.org/stable/c/2cfa537674cd1051a3b8111536d77d0558f33d5dPatch
- https://git.kernel.org/stable/c/4d542ddb88fb2f39bf7f14caa2902f3e8d06f6baPatch
- https://git.kernel.org/stable/c/53e0db429b37a32b8fc706d0d90eb4583ad13848Patch
- https://git.kernel.org/stable/c/6eba92a4d4be8feb4dc33976abac544fa99d6eccPatch
- https://git.kernel.org/stable/c/7cf64d8679ca1cb20cf57d6a88bfee79a0922a66Patch
- https://git.kernel.org/stable/c/b9b34ddbe2076ade359cd5ce7537d5ed019e9807Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.