netdev - [PATCH v5 net 1/2] net: remove unnecessary rotation

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <d5d7d41ab1b618832ad33be4a8d62967692f950a.1502761278.git.shli@fb.com>
Date:   Mon, 14 Aug 2017 19:53:20 -0700
From:   Shaohua Li <shli@...nel.org>
To:     netdev@...r.kernel.org, davem@...emloft.net
Cc:     Kernel-team@...com, Shaohua Li <shli@...com>
Subject: [PATCH v5 net 1/2] net: remove unnecessary rotation

From: Shaohua Li <shli@...com>

According to David Miller, the rotation doesn't really help avoid
security problem, so delte it.

Suggested-by: David Miller <davem@...emloft.net>
Signed-off-by: Shaohua Li <shli@...com>
---
 include/net/ipv6.h | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index 6eac5cf..7548367 100644
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -790,12 +790,6 @@ static inline __be32 ip6_make_flowlabel(struct net *net, struct sk_buff *skb,
 
 	hash = skb_get_hash_flowi6(skb, fl6);
 
-	/* Since this is being sent on the wire obfuscate hash a bit
-	 * to minimize possbility that any useful information to an
-	 * attacker is leaked. Only lower 20 bits are relevant.
-	 */
-	rol32(hash, 16);
-
 	flowlabel = (__force __be32)hash & IPV6_FLOWLABEL_MASK;
 
 	if (net->ipv6.sysctl.flowlabel_state_ranges)
-- 
2.9.5