CVE-2023-52924

Description

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 nf_tables_set_elem_destroy(), 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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

References

• https://git.kernel.org/stable/c/94313a196b44184b5b52c1876da6a537701b425a ↗
• https://git.kernel.org/stable/c/1da4874d05da1526b11b82fc7f3c7ac38749ddf8 ↗
• https://git.kernel.org/stable/c/b15ea4017af82011dd55225ce77cce3d4dfc169c ↗
• https://git.kernel.org/stable/c/7c7e658a36f8b1522bd3586d8137e5f93a25ddc5 ↗
• https://git.kernel.org/stable/c/59dab3bf0b8fc08eb802721c0532f13dd89209b8 ↗
• https://git.kernel.org/stable/c/bd156ce9553dcaf2d6ee2c825d1a5a1718e86524 ↗
• https://git.kernel.org/stable/c/24138933b97b055d486e8064b4a1721702442a9b ↗