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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/inet_connection_sock.c
parent0a14842f5a3c0e88a1e59fac5c3025db39721f74 (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/inet_connection_sock.c')
-rw-r--r--net/ipv4/inet_connection_sock.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 8514db54a7f4..3282cb2de393 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -354,20 +354,20 @@ struct dst_entry *inet_csk_route_req(struct sock *sk,
{
struct rtable *rt;
const struct inet_request_sock *ireq = inet_rsk(req);
- struct ip_options *opt = inet_rsk(req)->opt;
+ struct ip_options_rcu *opt = inet_rsk(req)->opt;
struct net *net = sock_net(sk);
struct flowi4 fl4;
flowi4_init_output(&fl4, sk->sk_bound_dev_if, sk->sk_mark,
RT_CONN_FLAGS(sk), RT_SCOPE_UNIVERSE,
sk->sk_protocol, inet_sk_flowi_flags(sk),
- (opt && opt->srr) ? opt->faddr : ireq->rmt_addr,
+ (opt && opt->opt.srr) ? opt->opt.faddr : ireq->rmt_addr,
ireq->loc_addr, ireq->rmt_port, inet_sk(sk)->inet_sport);
security_req_classify_flow(req, flowi4_to_flowi(&fl4));
rt = ip_route_output_flow(net, &fl4, sk);
if (IS_ERR(rt))
goto no_route;
- if (opt && opt->is_strictroute && rt->rt_dst != rt->rt_gateway)
+ if (opt && opt->opt.is_strictroute && rt->rt_dst != rt->rt_gateway)
goto route_err;
return &rt->dst;

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