This is a note to let you know that I've just added the patch titled
netlink: use jhash as hashfn for rhashtable
to the 3.18-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
netlink-use-jhash-as-hashfn-for-rhashtable.patch
and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Sun Dec 14 08:37:47 PST 2014
From: Daniel Borkmann <dborkman@xxxxxxxxxx>
Date: Wed, 10 Dec 2014 16:33:10 +0100
Subject: netlink: use jhash as hashfn for rhashtable
From: Daniel Borkmann <dborkman@xxxxxxxxxx>
[ Upstream commit 7f19fc5e0b617593dcda0d9956adc78b559ef1f5 ]
For netlink, we shouldn't be using arch_fast_hash() as a hashing
discipline, but rather jhash() instead.
Since netlink sockets can be opened by any user, a local attacker
would be able to easily create collisions with the DPDK-derived
arch_fast_hash(), which trades off performance for security by
using crc32 CPU instructions on x86_64.
While it might have a legimite use case in other places, it should
be avoided in netlink context, though. As rhashtable's API is very
flexible, we could later on still decide on other hashing disciplines,
if legitimate.
Reference: http://thread.gmane.org/gmane.linux.kernel/1844123
Fixes: e341694e3eb5 ("netlink: Convert netlink_lookup() to use RCU protected hash table")
Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Daniel Borkmann <dborkman@xxxxxxxxxx>
Acked-by: Thomas Graf <tgraf@xxxxxxx>
Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/netlink/af_netlink.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -3130,7 +3130,7 @@ static int __init netlink_proto_init(voi
.head_offset = offsetof(struct netlink_sock, node),
.key_offset = offsetof(struct netlink_sock, portid),
.key_len = sizeof(u32), /* portid */
- .hashfn = arch_fast_hash,
+ .hashfn = jhash,
.max_shift = 16, /* 64K */
.grow_decision = rht_grow_above_75,
.shrink_decision = rht_shrink_below_30,
Patches currently in stable-queue which might be from dborkman@xxxxxxxxxx are
queue-3.18/net-sctp-use-max_header-for-headroom-reserve-in-output-path.patch
queue-3.18/netlink-use-jhash-as-hashfn-for-rhashtable.patch
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