From 355b98553789b646ed97ad801a619ff898471b92 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Wed, 27 Mar 2019 08:21:30 -0700 Subject: netns: provide pure entropy for net_hash_mix() net_hash_mix() currently uses kernel address of a struct net, and is used in many places that could be used to reveal this address to a patient attacker, thus defeating KASLR, for the typical case (initial net namespace, &init_net is not dynamically allocated) I believe the original implementation tried to avoid spending too many cycles in this function, but security comes first. Also provide entropy regardless of CONFIG_NET_NS. Fixes: 0b4419162aa6 ("netns: introduce the net_hash_mix "salt" for hashes") Signed-off-by: Eric Dumazet Reported-by: Amit Klein Reported-by: Benny Pinkas Cc: Pavel Emelyanov Signed-off-by: David S. Miller --- net/core/net_namespace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'net') diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c index 17f36317363d..7e6dcc625701 100644 --- a/net/core/net_namespace.c +++ b/net/core/net_namespace.c @@ -304,6 +304,7 @@ static __net_init int setup_net(struct net *net, struct user_namespace *user_ns) refcount_set(&net->count, 1); refcount_set(&net->passive, 1); + get_random_bytes(&net->hash_mix, sizeof(u32)); net->dev_base_seq = 1; net->user_ns = user_ns; idr_init(&net->netns_ids); -- cgit v1.2.3-59-g8ed1b