xfrm: add rcu protection to sk->sk_policy[]
XFRM can deal with SYNACK messages, sent while listener socket
is not locked. We add proper rcu protection to __xfrm_sk_clone_policy()
and xfrm_sk_policy_lookup()
This might serve as the first step to remove xfrm.xfrm_policy_lock
use in fast path.
Fixes: fa76ce7328b2 ("inet: get rid of central tcp/dccp listener timer")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index 8bae1ef..d6f6e50 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -1142,12 +1142,14 @@
return xfrm_route_forward(skb, AF_INET6);
}
-int __xfrm_sk_clone_policy(struct sock *sk);
+int __xfrm_sk_clone_policy(struct sock *sk, const struct sock *osk);
-static inline int xfrm_sk_clone_policy(struct sock *sk)
+static inline int xfrm_sk_clone_policy(struct sock *sk, const struct sock *osk)
{
- if (unlikely(sk->sk_policy[0] || sk->sk_policy[1]))
- return __xfrm_sk_clone_policy(sk);
+ sk->sk_policy[0] = NULL;
+ sk->sk_policy[1] = NULL;
+ if (unlikely(osk->sk_policy[0] || osk->sk_policy[1]))
+ return __xfrm_sk_clone_policy(sk, osk);
return 0;
}
@@ -1155,12 +1157,16 @@
static inline void xfrm_sk_free_policy(struct sock *sk)
{
- if (unlikely(sk->sk_policy[0] != NULL)) {
- xfrm_policy_delete(sk->sk_policy[0], XFRM_POLICY_MAX);
+ struct xfrm_policy *pol;
+
+ pol = rcu_dereference_protected(sk->sk_policy[0], 1);
+ if (unlikely(pol != NULL)) {
+ xfrm_policy_delete(pol, XFRM_POLICY_MAX);
sk->sk_policy[0] = NULL;
}
- if (unlikely(sk->sk_policy[1] != NULL)) {
- xfrm_policy_delete(sk->sk_policy[1], XFRM_POLICY_MAX+1);
+ pol = rcu_dereference_protected(sk->sk_policy[1], 1);
+ if (unlikely(pol != NULL)) {
+ xfrm_policy_delete(pol, XFRM_POLICY_MAX+1);
sk->sk_policy[1] = NULL;
}
}
@@ -1170,7 +1176,7 @@
#else
static inline void xfrm_sk_free_policy(struct sock *sk) {}
-static inline int xfrm_sk_clone_policy(struct sock *sk) { return 0; }
+static inline int xfrm_sk_clone_policy(struct sock *sk, const struct sock *osk) { return 0; }
static inline int xfrm6_route_forward(struct sk_buff *skb) { return 1; }
static inline int xfrm4_route_forward(struct sk_buff *skb) { return 1; }
static inline int xfrm6_policy_check(struct sock *sk, int dir, struct sk_buff *skb)