| Message ID | 1418225592-29322-2-git-send-email-dborkman@redhat.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 63aa5c8..9642e52 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,
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> --- net/netlink/af_netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)