netlink: use jhash as hashfn for rhashtable
authorDaniel Borkmann <dborkman@redhat.com>
Wed, 10 Dec 2014 15:33:10 +0000 (16:33 +0100)
committerDavid S. Miller <davem@davemloft.net>
Wed, 10 Dec 2014 20:17:45 +0000 (15:17 -0500)
commit7f19fc5e0b617593dcda0d9956adc78b559ef1f5
treeb70a8c285a3d413e90f4329db76b1cc777d1de03
parent7d339890e79fd9a0508f2781e318b57dfb44b810
netlink: use jhash as hashfn for rhashtable

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@gondor.apana.org.au>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/netlink/af_netlink.c