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authorEric Dumazet <eric.dumazet@gmail.com>2011-04-21 09:45:37 +0000
committerDavid S. Miller <davem@davemloft.net>2011-04-28 13:16:35 -0700
commitf6d8bd051c391c1c0458a30b2a7abcd939329259 (patch)
tree1dc4daecdeb0b42c2c6b59d7d6b41e091c11db5f /net/ipv4/af_inet.c
parent0a14842f5a3c0e88a1e59fac5c3025db39721f74 (diff)
downloadlinux-f6d8bd051c391c1c0458a30b2a7abcd939329259.tar.bz2
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/af_inet.c')
-rw-r--r--net/ipv4/af_inet.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 0413af3e2285..963a621e75c7 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -153,7 +153,7 @@ void inet_sock_destruct(struct sock *sk)
WARN_ON(sk->sk_wmem_queued);
WARN_ON(sk->sk_forward_alloc);
- kfree(inet->opt);
+ kfree(rcu_dereference_protected(inet->inet_opt, 1));
dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
sk_refcnt_debug_dec(sk);
}
@@ -1106,9 +1106,12 @@ static int inet_sk_reselect_saddr(struct sock *sk)
struct flowi4 fl4;
struct rtable *rt;
__be32 new_saddr;
+ struct ip_options_rcu *inet_opt;
- if (inet->opt && inet->opt->srr)
- daddr = inet->opt->faddr;
+ inet_opt = rcu_dereference_protected(inet->inet_opt,
+ sock_owned_by_user(sk));
+ if (inet_opt && inet_opt->opt.srr)
+ daddr = inet_opt->opt.faddr;
/* Query new route. */
rt = ip_route_connect(&fl4, daddr, 0, RT_CONN_FLAGS(sk),
@@ -1148,6 +1151,7 @@ int inet_sk_rebuild_header(struct sock *sk)
struct inet_sock *inet = inet_sk(sk);
struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
__be32 daddr;
+ struct ip_options_rcu *inet_opt;
int err;
/* Route is OK, nothing to do. */
@@ -1155,9 +1159,12 @@ int inet_sk_rebuild_header(struct sock *sk)
return 0;
/* Reroute. */
+ rcu_read_lock();
+ inet_opt = rcu_dereference(inet->inet_opt);
daddr = inet->inet_daddr;
- if (inet->opt && inet->opt->srr)
- daddr = inet->opt->faddr;
+ if (inet_opt && inet_opt->opt.srr)
+ daddr = inet_opt->opt.faddr;
+ rcu_read_unlock();
rt = ip_route_output_ports(sock_net(sk), sk, daddr, inet->inet_saddr,
inet->inet_dport, inet->inet_sport,
sk->sk_protocol, RT_CONN_FLAGS(sk),