medium
5.5
Advisory Published
Updated

CVE-2024-50163: bpf: Make sure internal and UAPI bpf_redirect flags don't overlap

First published: Thu Nov 07 2024(Updated: )

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.

Credit: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Affected SoftwareAffected VersionHow to fix
Linux Kernel>=5.14<5.15.170
Linux Kernel>=5.16<6.1.115
Linux Kernel>=6.2<6.6.59
Linux Kernel>=6.7<6.11.6
Linux Kernel=6.12-rc1
Linux Kernel=6.12-rc2
Linux Kernel=6.12-rc3
debian/linux
5.10.223-1
5.10.226-1
6.1.123-1
6.1.128-1
6.12.12-1
6.12.15-1
debian/linux-6.1
6.1.119-1~deb11u1

Remedy

https://git.kernel.org/stable/c/09d88791c7cd888d5195c84733caf9183dcfbd16

Remedy

https://git.kernel.org/stable/c/0fca5ed4be8e8bfbfb9bd97845af596bab7192d3

Remedy

https://git.kernel.org/stable/c/314dbee9fe4f5cee36435465de52c988d7caa466

Remedy

https://git.kernel.org/stable/c/4e1e428533845d48828bd3875c0e92e8565b9962

Remedy

https://git.kernel.org/stable/c/cec288e05ceac9a0d3a3a1fd279534b11844c826

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Reference Links

Frequently Asked Questions

  • What is the severity of CVE-2024-50163?

    CVE-2024-50163 has a medium severity rating due to potential security implications in the Linux kernel.

  • How do I fix CVE-2024-50163?

    To fix CVE-2024-50163, update your Linux kernel to a version that contains the patch for this vulnerability.

  • Which versions of the Linux kernel are affected by CVE-2024-50163?

    CVE-2024-50163 affects multiple versions of the Linux kernel between 5.14 and 6.12-rc3.

  • What components are impacted by CVE-2024-50163?

    CVE-2024-50163 impacts the bpf_redirect_info used in both SKB and XDP redirect paths.

  • Is CVE-2024-50163 a remote exploit vulnerability?

    CVE-2024-50163 could potentially allow an attacker to execute unauthorized actions, but specific exploit scenarios depend on the system's configuration.

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