netfilter: xt_u32: validate user space input

mainline inclusion
from mainline-v6.6-rc1
commit 69c5d284
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I85CAT
CVE: CVE-2023-39192

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=69c5d284f67089b4750d28ff6ac6f52ec224b330



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The xt_u32 module doesn't validate the fields in the xt_u32 structure.
An attacker may take advantage of this to trigger an OOB read by setting
the size fields with a value beyond the arrays boundaries.

Add a checkentry function to validate the structure.

This was originally reported by the ZDI project (ZDI-CAN-18408).

Fixes: 1b50b8a3 ("[NETFILTER]: Add u32 match")
Cc: stable@vger.kernel.org
Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Lu Wei <luwei32@huawei.com>