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authorDaniel Borkmann <dborkman@redhat.com>2014-12-10 16:33:10 +0100
committerDavid S. Miller <davem@davemloft.net>2014-12-10 15:17:45 -0500
commit7f19fc5e0b617593dcda0d9956adc78b559ef1f5 (patch)
treeb70a8c285a3d413e90f4329db76b1cc777d1de03
parent7d339890e79fd9a0508f2781e318b57dfb44b810 (diff)
downloadlinux-7f19fc5e0b617593dcda0d9956adc78b559ef1f5.tar.gz
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>
-rw-r--r--net/netlink/af_netlink.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index cc9bcf008b03..ef5f77b44ec7 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -3129,7 +3129,7 @@ static int __init netlink_proto_init(void)
.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,