diff options
| author | Eric Dumazet <eric.dumazet@gmail.com> | 2011-04-21 09:45:37 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2011-04-28 13:16:35 -0700 |
| commit | f6d8bd051c391c1c0458a30b2a7abcd939329259 (patch) | |
| tree | 1dc4daecdeb0b42c2c6b59d7d6b41e091c11db5f /net/ipv4/syncookies.c | |
| parent | 0a14842f5a3c0e88a1e59fac5c3025db39721f74 (diff) | |
inet: add RCU protection to inet->opt
We lack proper synchronization to manipulate inet->opt ip_options
Problem is ip_make_skb() calls ip_setup_cork() and
ip_setup_cork() possibly makes a copy of ipc->opt (struct ip_options),
without any protection against another thread manipulating inet->opt.
Another thread can change inet->opt pointer and free old one under us.
Use RCU to protect inet->opt (changed to inet->inet_opt).
Instead of handling atomic refcounts, just copy ip_options when
necessary, to avoid cache line dirtying.
We cant insert an rcu_head in struct ip_options since its included in
skb->cb[], so this patch is large because I had to introduce a new
ip_options_rcu structure.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/syncookies.c')
| -rw-r--r-- | net/ipv4/syncookies.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/syncookies.c b/net/ipv4/syncookies.c index 71e029691908..26461492a847 100644 --- a/net/ipv4/syncookies.c +++ b/net/ipv4/syncookies.c @@ -321,10 +321,10 @@ struct sock *cookie_v4_check(struct sock *sk, struct sk_buff *skb, * the ACK carries the same options again (see RFC1122 4.2.3.8) */ if (opt && opt->optlen) { - int opt_size = sizeof(struct ip_options) + opt->optlen; + int opt_size = sizeof(struct ip_options_rcu) + opt->optlen; ireq->opt = kmalloc(opt_size, GFP_ATOMIC); - if (ireq->opt != NULL && ip_options_echo(ireq->opt, skb)) { + if (ireq->opt != NULL && ip_options_echo(&ireq->opt->opt, skb)) { kfree(ireq->opt); ireq->opt = NULL; } |