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| author |   Hannes Frederic Sowa <hannes@stressinduktion.org> | 2013-10-23 11:06:55 +0200 |
|---|---|---|
| committer |   David S. Miller <davem@davemloft.net> | 2013-10-23 17:01:40 -0400 |
| commit | e7b519ba55aeb675daee1d304e80d752c385f7f0 (patch) | |
| tree | f9152523b9420b14557f22675b0e9ffab5d7b0b9 /net/ipv4 | |
| parent | Merge branch 'pci_set_drvdata' (diff) | |
| download | linux-dev-e7b519ba55aeb675daee1d304e80d752c385f7f0.tar.xz linux-dev-e7b519ba55aeb675daee1d304e80d752c385f7f0.zip | |
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 <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/ip_fragment.c | 1 |
1 files changed, 1 insertions, 0 deletions
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); |