CVE-2024-50038 Affecting kernel-rt-core package, versions *


Severity

Recommended
0.0
medium
0
10

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.04% (6th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELRTCORE-8286203
  • published23 Oct 2024
  • disclosed21 Oct 2024

Introduced: 21 Oct 2024

CVE-2024-50038  (opens in a new tab)
First added by Snyk

How to fix?

There is no fixed version for RHEL:8 kernel-rt-core.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-core package and not the kernel-rt-core package as distributed by RHEL. See How to fix? for RHEL:8 relevant fixed versions and status.

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

netfilter: xtables: avoid NFPROTO_UNSPEC where needed

syzbot managed to call xt_cluster match via ebtables:

WARNING: CPU: 0 PID: 11 at net/netfilter/xt_cluster.c:72 xt_cluster_mt+0x196/0x780 [..] ebt_do_table+0x174b/0x2a40

Module registers to NFPROTO_UNSPEC, but it assumes ipv4/ipv6 packet processing. As this is only useful to restrict locally terminating TCP/UDP traffic, register this for ipv4 and ipv6 family only.

Pablo points out that this is a general issue, direct users of the set/getsockopt interface can call into targets/matches that were only intended for use with ip(6)tables.

Check all UNSPEC matches and targets for similar issues:

  • matches and targets are fine except if they assume skb_network_header() is valid -- this is only true when called from inet layer: ip(6) stack pulls the ip/ipv6 header into linear data area.
  • targets that return XT_CONTINUE or other xtables verdicts must be restricted too, they are incompatbile with the ebtables traverser, e.g. EBT_CONTINUE is a completely different value than XT_CONTINUE.

Most matches/targets are changed to register for NFPROTO_IPV4/IPV6, as they are provided for use by ip(6)tables.

The MARK target is also used by arptables, so register for NFPROTO_ARP too.

While at it, bail out if connbytes fails to enable the corresponding conntrack family.

This change passes the selftests in iptables.git.

CVSS Scores

version 3.1