From e7b519ba55aeb675daee1d304e80d752c385f7f0 Mon Sep 17 00:00:00 2001 From: Hannes Frederic Sowa Date: Wed, 23 Oct 2013 11:06:55 +0200 Subject: [PATCH] ipv4: initialize ip4_frags hash secret as late as possible Defer the generation of the first hash secret for the ipv4 fragmentation cache as late as possible. ip4_frags.rnd gets initial seeded by inet_frags_init and regulary reseeded by inet_frag_secret_rebuild. Either we call ipqhashfn directly from ip_fragment.c in which case we initialize the secret directly. If we first get called by inet_frag_secret_rebuild we install a new secret by a manual call to get_random_bytes. This secret will be overwritten as soon as the first call to ipqhashfn happens. This is safe because we won't race while publishing the new secrets with anyone else. Cc: Eric Dumazet Cc: "David S. Miller" Signed-off-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/ipv4/ip_fragment.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c index b66910aaef4d..2481993a4970 100644 --- a/net/ipv4/ip_fragment.c +++ b/net/ipv4/ip_fragment.c @@ -106,6 +106,7 @@ struct ip4_create_arg { static unsigned int ipqhashfn(__be16 id, __be32 saddr, __be32 daddr, u8 prot) { + net_get_random_once(&ip4_frags.rnd, sizeof(ip4_frags.rnd)); return jhash_3words((__force u32)id << 16 | prot, (__force u32)saddr, (__force u32)daddr, ip4_frags.rnd) & (INETFRAGS_HASHSZ - 1); -- 2.39.5