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authorEric Dumazet <eric.dumazet@gmail.com>2012-04-05 22:17:46 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-04-27 09:51:19 -0700
commit19a8321ccebc1db80a75d32d0235f2beb646d8f7 (patch)
tree6f013ba8b378bc033fd5c1f58e3252b40750c7fd
parent589336f3c7731b608e860e984f753909b00efad7 (diff)
netlink: fix races after skb queueing
[ Upstream commit 4a7e7c2ad540e54c75489a70137bf0ec15d3a127 ] As soon as an skb is queued into socket receive_queue, another thread can consume it, so we are not allowed to reference skb anymore, or risk use after free. Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/netlink/af_netlink.c24
1 files changed, 13 insertions, 11 deletions
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 6ef64adf7362..24bc620b539a 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -830,12 +830,19 @@ int netlink_attachskb(struct sock *sk, struct sk_buff *skb,
return 0;
}
-int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
+static int __netlink_sendskb(struct sock *sk, struct sk_buff *skb)
{
int len = skb->len;
skb_queue_tail(&sk->sk_receive_queue, skb);
sk->sk_data_ready(sk, len);
+ return len;
+}
+
+int netlink_sendskb(struct sock *sk, struct sk_buff *skb)
+{
+ int len = __netlink_sendskb(sk, skb);
+
sock_put(sk);
return len;
}
@@ -960,8 +967,7 @@ static inline int netlink_broadcast_deliver(struct sock *sk,
if (atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf &&
!test_bit(0, &nlk->state)) {
skb_set_owner_r(skb, sk);
- skb_queue_tail(&sk->sk_receive_queue, skb);
- sk->sk_data_ready(sk, skb->len);
+ __netlink_sendskb(sk, skb);
return atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf;
}
return -1;
@@ -1682,10 +1688,8 @@ static int netlink_dump(struct sock *sk)
if (sk_filter(sk, skb))
kfree_skb(skb);
- else {
- skb_queue_tail(&sk->sk_receive_queue, skb);
- sk->sk_data_ready(sk, skb->len);
- }
+ else
+ __netlink_sendskb(sk, skb);
return 0;
}
@@ -1697,10 +1701,8 @@ static int netlink_dump(struct sock *sk)
if (sk_filter(sk, skb))
kfree_skb(skb);
- else {
- skb_queue_tail(&sk->sk_receive_queue, skb);
- sk->sk_data_ready(sk, skb->len);
- }
+ else
+ __netlink_sendskb(sk, skb);
if (cb->done)
cb->done(cb);