CVE-2023-52924

Source
https://nvd.nist.gov/vuln/detail/CVE-2023-52924
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-52924.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2023-52924
Downstream
Related
Published
2025-02-05T10:15:21Z
Modified
2025-08-09T20:01:26Z
Summary
[none]
Details

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

netfilter: nf_tables: don't skip expired elements during walk

There is an asymmetry between commit/abort and preparation phase if the following conditions are met:

  1. set is a verdict map ("1.2.3.4 : jump foo")
  2. timeouts are enabled

In this case, following sequence is problematic:

  1. element E in set S refers to chain C
  2. userspace requests removal of set S
  3. kernel does a set walk to decrement chain->use count for all elements from preparation phase
  4. kernel does another set walk to remove elements from the commit phase (or another walk to do a chain->use increment for all elements from abort phase)

If E has already expired in 1), it will be ignored during list walk, so its use count won't have been changed.

Then, when set is culled, ->destroy callback will zap the element via nftablessetelemdestroy(), but this function is only safe for elements that have been deactivated earlier from the preparation phase: lack of earlier deactivate removes the element but leaks the chain use count, which results in a WARN splat when the chain gets removed later, plus a leak of the nft_chain structure.

Update pipapo_get() not to skip expired elements, otherwise flush command reports bogus ENOENT errors.

References

Affected packages