Vulnerability CVE-2024-26609
Published: 2024-03-11

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

netfilter: nf_tables: reject QUEUE/DROP verdict parameters

This reverts commit e0abdadcc6e1.

core.c:nf_hook_slow assumes that the upper 16 bits of NF_DROP
verdicts contain a valid errno, i.e. -EPERM, -EHOSTUNREACH or similar,
or 0.

Due to the reverted commit, its possible to provide a positive
value, e.g. NF_ACCEPT (1), which results in use-after-free.

Its not clear to me why this commit was made.

NF_QUEUE is not used by nftables; "queue" rules in nftables
will result in use of "nft_queue" expression.

If we later need to allow specifiying errno values from userspace
(do not know why), this has to call NF_DROP_GETERR and check that
"err <= 0" holds true.

 References:
https://git.kernel.org/stable/c/8365e9d92b85fda975a5ece7a3a139cb964018c8
https://git.kernel.org/stable/c/4e66422f1b56149761dc76030e6345d1cca6f869
https://git.kernel.org/stable/c/55a60251fa50d4e68175e36666b536a602ce4f6c
https://git.kernel.org/stable/c/960cf4f812530f01f6acc6878ceaa5404c06af7b
https://git.kernel.org/stable/c/8e34430e33b8a80bc014f3efe29cac76bc30a4b4
https://git.kernel.org/stable/c/6653118b176a00915125521c6572ae8e507621db
https://git.kernel.org/stable/c/f05a497e7bc8851eeeb3a58da180ba469efebb05
https://git.kernel.org/stable/c/f342de4e2f33e0e39165d8639387aa6c19dff660
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