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authorEric Dumazet <edumazet@google.com>2019-03-27 08:21:30 -0700
committerDavid S. Miller <davem@davemloft.net>2019-03-28 17:00:45 -0700
commit355b98553789b646ed97ad801a619ff898471b92 (patch)
tree433cd3a5856dfdcc1022cb5cc2e7c1aa0bf383e3 /net
parent6289d0facd9ebce4cc83e5da39e15643ee998dc5 (diff)
downloadlinux-355b98553789b646ed97ad801a619ff898471b92.tar.bz2
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 <edumazet@google.com> Reported-by: Amit Klein <aksecurity@gmail.com> Reported-by: Benny Pinkas <benny@pinkas.net> Cc: Pavel Emelyanov <xemul@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/core/net_namespace.c1
1 files changed, 1 insertions, 0 deletions
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);