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

netfilter: ebtables: fix OOB read in compat_mtw_from_user

Luxiao Xu says:

 The function compat_mtw_from_user() converts ebtables extensions from
 32-bit user structures to kernel native structures. However, it lacks
 proper validation of the user-supplied match_size/target_size.

 When certain extensions are processed, the kernel-side translation
 logic may perform memory accesses based on the extension's expected
 size. If the user provides a size smaller than what the extension
 requires, it results in an out-of-bounds read as reported by KASAN.

 This fix introduces a check to ensure match_size is at least as large
 as the extension's required compatsize. This covers matches, watchers,
 and targets, while maintaining compatibility with standard targets.

AFAIU this is relevant for matches that need to go though
match->compat_from_user() call.  Those that use plain memcpy with the
user-provided size are ok because the caller checks that size vs the
start of the next rule entry offset (which itself is checked vs. total
size copied from userspace).

The ->compat_from_user() callbacks assume they can read compatsize bytes,
so they need this extra check.

Based on an earlier patch from Luxiao Xu.

https://git.kernel.org/stable/c/21af4c030567d2e6c89bb927bc18b51fba52a400

https://git.kernel.org/stable/c/7ad0e463fc7eafae2141cc38054264636f8b3e94

https://git.kernel.org/stable/c/a27cb7325a6c69970041c7f8541fafed5a1ea3ec

https://git.kernel.org/stable/c/bf8e8eac7ede51dc318e06acef5a896dcbba7595

https://git.kernel.org/stable/c/d7a8fb6f10d55a1c37b0bf8c20cca24dffd76e00

https://git.kernel.org/stable/c/dad9ebf8107955bb54bd3f9cf22591b6ff37bac1

https://git.kernel.org/stable/c/f438d1786d657d57790c5d138d6db3fc9fdac392

https://git.kernel.org/stable/c/fcc4c043d137e7f1de4673dba1f3116e45377c67

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