NULL Pointer Dereference Affecting kernel-default-livepatch package, versions <6.4.0-150600.23.38.1


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.03% (8th percentile)

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  • Snyk IDSNYK-SLES156-KERNELDEFAULTLIVEPATCH-8723074
  • published14 Feb 2025
  • disclosed13 Feb 2025

Introduced: 13 Feb 2025

CVE-2024-49978  (opens in a new tab)
CWE-476  (opens in a new tab)

How to fix?

Upgrade SLES:15.6 kernel-default-livepatch to version 6.4.0-150600.23.38.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default-livepatch package and not the kernel-default-livepatch package as distributed by SLES. See How to fix? for SLES:15.6 relevant fixed versions and status.

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

gso: fix udp gso fraglist segmentation after pull from frag_list

Detect gso fraglist skbs with corrupted geometry (see below) and pass these to skb_segment instead of skb_segment_list, as the first can segment them correctly.

Valid SKB_GSO_FRAGLIST skbs

  • consist of two or more segments
  • the head_skb holds the protocol headers plus first gso_size
  • one or more frag_list skbs hold exactly one segment
  • all but the last must be gso_size

Optional datapath hooks such as NAT and BPF (bpf_skb_pull_data) can modify these skbs, breaking these invariants.

In extreme cases they pull all data into skb linear. For UDP, this causes a NULL ptr deref in __udpv4_gso_segment_list_csum at udp_hdr(seg->next)->dest.

Detect invalid geometry due to pull, by checking head_skb size. Don't just drop, as this may blackhole a destination. Convert to be able to pass to regular skb_segment.

CVSS Base Scores

version 3.1