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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Colin Ian King <colin.king@canonical.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.4 009/107] ipv6: fix useless rol32 call on hash
Date:   Mon, 23 Jul 2018 14:41:03 +0200
Message-Id: <20180723122413.346242790@linuxfoundation.org>
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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Colin Ian King <colin.king@canonical.com>

[ Upstream commit 169dc027fb02492ea37a0575db6a658cf922b854 ]

The rol32 call is currently rotating hash but the rol'd value is
being discarded. I believe the current code is incorrect and hash
should be assigned the rotated value returned from rol32.

Thanks to David Lebrun for spotting this.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/ipv6.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -762,7 +762,7 @@ static inline __be32 ip6_make_flowlabel(
 	 * to minimize possbility that any useful information to an
 	 * attacker is leaked. Only lower 20 bits are relevant.
 	 */
-	rol32(hash, 16);
+	hash = rol32(hash, 16);
 
 	flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;