CVE-2024-49978

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux9fd1ff5d2ac7181844735806b0a703c942365291 < 080e6c9a3908de193a48f646c5ce1bfb15676ffcaffected
LinuxLinux9fd1ff5d2ac7181844735806b0a703c942365291 < af3122f5fdc0d00581d6e598a668df6bf54c9daaaffected
LinuxLinux9fd1ff5d2ac7181844735806b0a703c942365291 < 33e28acf42ee863f332a958bfc2f1a284a3659dfaffected
LinuxLinux9fd1ff5d2ac7181844735806b0a703c942365291 < 3cd00d2e3655fad3bda96dc1ebf17b6495f86feaaffected
LinuxLinux9fd1ff5d2ac7181844735806b0a703c942365291 < a1e40ac5b5e9077fe1f7ae0eb88034db0f9ae1abaffected
LinuxLinux5.6affected
LinuxLinux0 < 5.6unaffected
LinuxLinux6.1.113 <= 6.1.*unaffected
LinuxLinux6.6.55 <= 6.6.*unaffected
LinuxLinux6.10.14 <= 6.10.*unaffected
LinuxLinux6.11.3 <= 6.11.*unaffected
LinuxLinux6.12 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References