Deadlock Affecting kernel-rt-devel package, versions <0:4.18.0-553.16.1.rt7.357.el8_10


Severity

Recommended
high

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.05% (17th percentile)

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  • Snyk IDSNYK-RHEL8-KERNELRTDEVEL-6541942
  • published4 Apr 2024
  • disclosed3 Apr 2024

Introduced: 3 Apr 2024

CVE-2024-26740  (opens in a new tab)
CWE-833  (opens in a new tab)
First added by Snyk

How to fix?

Upgrade RHEL:8 kernel-rt-devel to version 0:4.18.0-553.16.1.rt7.357.el8_10 or higher.
This issue was patched in RHSA-2024:5102.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-rt-devel package and not the kernel-rt-devel 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:

net/sched: act_mirred: use the backlog for mirred ingress

The test Davide added in commit ca22da2fbd69 ("act_mirred: use the backlog for nested calls to mirred ingress") hangs our testing VMs every 10 or so runs, with the familiar tcp_v4_rcv -> tcp_v4_rcv deadlock reported by lockdep.

The problem as previously described by Davide (see Link) is that if we reverse flow of traffic with the redirect (egress -> ingress) we may reach the same socket which generated the packet. And we may still be holding its socket lock. The common solution to such deadlocks is to put the packet in the Rx backlog, rather than run the Rx path inline. Do that for all egress -> ingress reversals, not just once we started to nest mirred calls.

In the past there was a concern that the backlog indirection will lead to loss of error reporting / less accurate stats. But the current workaround does not seem to address the issue.

CVSS Scores

version 3.1