netdev - [PATCH net 1/2] nft_set_pipapo: fix incorrect avx2 match of 5th field octet

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Message-Id: <20250410103647.1030244-2-pablo@netfilter.org>
Date: Thu, 10 Apr 2025 12:36:46 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net,
	netdev@...r.kernel.org,
	kuba@...nel.org,
	pabeni@...hat.com,
	edumazet@...gle.com,
	fw@...len.de,
	horms@...nel.org
Subject: [PATCH net 1/2] nft_set_pipapo: fix incorrect avx2 match of 5th field octet

From: Florian Westphal <fw@...len.de>

Given a set element like:

	icmpv6 . dead:beef:00ff::1

The value of 'ff' is irrelevant, any address will be matched
as long as the other octets are the same.

This is because of too-early register clobbering:
ymm7 is reloaded with new packet data (pkt[9])  but it still holds data
of an earlier load that wasn't processed yet.

The existing tests in nft_concat_range.sh selftests do exercise this code
path, but do not trigger incorrect matching due to the network prefix
limitation.

Fixes: 7400b063969b ("nft_set_pipapo: Introduce AVX2-based lookup implementation")
Reported-by: sontu mazumdar <sontu21@...il.com>
Closes: https://lore.kernel.org/netfilter/CANgxkqwnMH7fXra+VUfODT-8+qFLgskq3set1cAzqqJaV4iEZg@mail.gmail.com/T/#t
Reviewed-by: Stefano Brivio <sbrivio@...hat.com>
Signed-off-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
 net/netfilter/nft_set_pipapo_avx2.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/netfilter/nft_set_pipapo_avx2.c b/net/netfilter/nft_set_pipapo_avx2.c
index b8d3c3213efe..c15db28c5ebc 100644
--- a/net/netfilter/nft_set_pipapo_avx2.c
+++ b/net/netfilter/nft_set_pipapo_avx2.c
@@ -994,8 +994,9 @@ static int nft_pipapo_avx2_lookup_8b_16(unsigned long *map, unsigned long *fill,
 		NFT_PIPAPO_AVX2_BUCKET_LOAD8(5, lt,  8,  pkt[8], bsize);
 
 		NFT_PIPAPO_AVX2_AND(6, 2, 3);
+		NFT_PIPAPO_AVX2_AND(3, 4, 7);
 		NFT_PIPAPO_AVX2_BUCKET_LOAD8(7, lt,  9,  pkt[9], bsize);
-		NFT_PIPAPO_AVX2_AND(0, 4, 5);
+		NFT_PIPAPO_AVX2_AND(0, 3, 5);
 		NFT_PIPAPO_AVX2_BUCKET_LOAD8(1, lt, 10, pkt[10], bsize);
 		NFT_PIPAPO_AVX2_AND(2, 6, 7);
 		NFT_PIPAPO_AVX2_BUCKET_LOAD8(3, lt, 11, pkt[11], bsize);
-- 
2.30.2