Messages in this thread Patch in this message | | | Date | Wed, 09 May 2012 06:51:39 +0100 | From | Ben Hutchings <> | Subject | [ 070/167] [PATCH 10/26] netlink: fix races after skb queueing |
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3.2-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <eric.dumazet@gmail.com>
[ 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 file 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); -- 1.7.10
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