linux-cve-announce - CVE-2025-38162: netfilter: nft_set_pipapo: prevent overflow in lookup table allocation

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Message-ID: <2025070340-CVE-2025-38162-cd74@gregkh>
Date: Thu,  3 Jul 2025 10:36:18 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-38162: netfilter: nft_set_pipapo: prevent overflow in lookup table allocation

From: Greg Kroah-Hartman <gregkh@...nel.org>

Description
===========

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

netfilter: nft_set_pipapo: prevent overflow in lookup table allocation

When calculating the lookup table size, ensure the following
multiplication does not overflow:

- desc->field_len[] maximum value is U8_MAX multiplied by
  NFT_PIPAPO_GROUPS_PER_BYTE(f) that can be 2, worst case.
- NFT_PIPAPO_BUCKETS(f->bb) is 2^8, worst case.
- sizeof(unsigned long), from sizeof(*f->lt), lt in
  struct nft_pipapo_field.

Then, use check_mul_overflow() to multiply by bucket size and then use
check_add_overflow() to the alignment for avx2 (if needed). Finally, add
lt_size_check_overflow() helper and use it to consolidate this.

While at it, replace leftover allocation using the GFP_KERNEL to
GFP_KERNEL_ACCOUNT for consistency, in pipapo_resize().

The Linux kernel CVE team has assigned CVE-2025-38162 to this issue.


Affected and fixed versions
===========================

	Issue introduced in 5.6 with commit 3c4287f62044a90e73a561aa05fc46e62da173da and fixed in 6.12.34 with commit c1360ac8156c0a3f2385baef91d8d26fd9d39701
	Issue introduced in 5.6 with commit 3c4287f62044a90e73a561aa05fc46e62da173da and fixed in 6.15.3 with commit 43fe1181f738295624696ae9ff611790edb65b5e
	Issue introduced in 5.6 with commit 3c4287f62044a90e73a561aa05fc46e62da173da and fixed in 6.16-rc1 with commit 4c5c6aa9967dbe55bd017bb509885928d0f31206

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2025-38162
will be updated if fixes are backported, please check that for the most
up to date information about this issue.


Affected files
==============

The file(s) affected by this issue are:
	net/netfilter/nft_set_pipapo.c


Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/c1360ac8156c0a3f2385baef91d8d26fd9d39701
	https://git.kernel.org/stable/c/43fe1181f738295624696ae9ff611790edb65b5e
	https://git.kernel.org/stable/c/4c5c6aa9967dbe55bd017bb509885928d0f31206