netfilter: nf_tables: reject QUEUE/DROP verdict parameters

netfilter: nf_tables: reject QUEUE/DROP verdict parameters

Origin: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git/commit?id=11351dcb86e3eec82492e20a63bb36f5a340dc85
Bug-Debian-Security: https://security-tracker.debian.org/tracker/CVE-2024-1086

commit f342de4e2f33e0e39165d8639387aa6c19dff660 upstream.

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.

Fixes: e0abdadcc6e1 ("netfilter: nf_tables: accept QUEUE/DROP verdict parameters")
Cc: stable@vger.kernel.org
Reported-by: Notselwyn <notselwyn@pwning.tech>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Gbp-Pq: Topic bugfix/all
Gbp-Pq: Name netfilter-nf_tables-reject-QUEUE-DROP-verdict-parame.patch