Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Eric Dumazet <edumazet@google.com>,
        Keyu Man <kman001@ucr.edu>, Willy Tarreau <w@1wt.eu>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.13 055/113] ipv4: use siphash instead of Jenkins in fnhe_hashfun()
Date:   Wed,  1 Sep 2021 14:28:10 +0200
Message-Id: <20210901122303.804423454@linuxfoundation.org>
In-Reply-To: <20210901122301.984263453@linuxfoundation.org>
References: <20210901122301.984263453@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Eric Dumazet <edumazet@google.com>

[ Upstream commit 6457378fe796815c973f631a1904e147d6ee33b1 ]

A group of security researchers brought to our attention
the weakness of hash function used in fnhe_hashfun().

Lets use siphash instead of Jenkins Hash, to considerably
reduce security risks.

Also remove the inline keyword, this really is distracting.

Fixes: d546c621542d ("ipv4: harden fnhe_hashfun()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Keyu Man <kman001@ucr.edu>
Cc: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/ipv4/route.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index 78d1e5afc452..d8811e1fbd6c 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -600,14 +600,14 @@ static struct fib_nh_exception *fnhe_oldest(struct fnhe_hash_bucket *hash)
 	return oldest;
 }
 
-static inline u32 fnhe_hashfun(__be32 daddr)
+static u32 fnhe_hashfun(__be32 daddr)
 {
-	static u32 fnhe_hashrnd __read_mostly;
-	u32 hval;
+	static siphash_key_t fnhe_hash_key __read_mostly;
+	u64 hval;
 
-	net_get_random_once(&fnhe_hashrnd, sizeof(fnhe_hashrnd));
-	hval = jhash_1word((__force u32)daddr, fnhe_hashrnd);
-	return hash_32(hval, FNHE_HASH_SHIFT);
+	net_get_random_once(&fnhe_hash_key, sizeof(fnhe_hash_key));
+	hval = siphash_1u32((__force u32)daddr, &fnhe_hash_key);
+	return hash_64(hval, FNHE_HASH_SHIFT);
 }
 
 static void fill_route_from_fnhe(struct rtable *rt, struct fib_nh_exception *fnhe)
-- 
2.30.2