Improper Input Validation Affecting kernel-headers package, versions <0:6.1.115-126.197.amzn2023


Severity

Recommended
high

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-AMZN2023-KERNELHEADERS-9521774
  • published27 Mar 2025
  • disclosed7 Nov 2024

Introduced: 7 Nov 2024

CVE-2024-50163  (opens in a new tab)
CWE-20  (opens in a new tab)

How to fix?

Upgrade Amazon-Linux:2023 kernel-headers to version 0:6.1.115-126.197.amzn2023 or higher.
This issue was patched in ALAS2023-2025-794.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-headers package and not the kernel-headers package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

bpf: Make sure internal and UAPI bpf_redirect flags don't overlap

The bpf_redirect_info is shared between the SKB and XDP redirect paths, and the two paths use the same numeric flag values in the ri->flags field (specifically, BPF_F_BROADCAST == BPF_F_NEXTHOP). This means that if skb bpf_redirect_neigh() is used with a non-NULL params argument and, subsequently, an XDP redirect is performed using the same bpf_redirect_info struct, the XDP path will get confused and end up crashing, which syzbot managed to trigger.

With the stack-allocated bpf_redirect_info, the structure is no longer shared between the SKB and XDP paths, so the crash doesn't happen anymore. However, different code paths using identically-numbered flag values in the same struct field still seems like a bit of a mess, so this patch cleans that up by moving the flag definitions together and redefining the three flags in BPF_F_REDIRECT_INTERNAL to not overlap with the flags used for XDP. It also adds a BUILD_BUG_ON() check to make sure the overlap is not re-introduced by mistake.

CVSS Base Scores

version 3.1