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From 0f7eb8a3cb853edf31ec23d26623b195603814b2 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 5 Apr 2012 22:17:46 +0000
Subject: [PATCH 067/165] 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: Ben Hutchings <ben@decadent.org.uk>
---
net/netlink/af_netlink.c | 24 +++++++++++++-----------
1 files changed, 13 insertions(+), 11 deletions(-)
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 1201b6d..a99fb41 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;
@@ -1684,10 +1690,8 @@ 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;
}
@@ -1701,10 +1705,8 @@ 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);
--
1.7.7.6
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