3.18-stable review patch. If anyone has any objections, please let me know.
------------------ From: Daniel Borkmann <[email protected]> [ 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 <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Acked-by: Thomas Graf <[email protected]> Acked-by: Hannes Frederic Sowa <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- 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, -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
