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authorEric Dumazet <eric.dumazet@gmail.com>2011-04-21 13:45:37 +0400
committerDavid S. Miller <davem@davemloft.net>2011-04-29 00:16:35 +0400
commitf6d8bd051c391c1c0458a30b2a7abcd939329259 (patch)
tree1dc4daecdeb0b42c2c6b59d7d6b41e091c11db5f /net/ipv4/syncookies.c
parent0a14842f5a3c0e88a1e59fac5c3025db39721f74 (diff)
downloadlinux-f6d8bd051c391c1c0458a30b2a7abcd939329259.tar.xz
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.c4
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;
}