From 956a79d503998a763dd71847f2f9eb19349c2aba Mon Sep 17 00:00:00 2001
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Sat, 29 May 2010 00:20:48 -0700
Subject: net: fix sk_forward_alloc corruptions
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commit 2903037400a26e7c0cc93ab75a7d62abfacdf485 upstream.

As David found out, sock_queue_err_skb() should be called with socket
lock hold, or we risk sk_forward_alloc corruption, since we use non
atomic operations to update this field.

This patch adds bh_lock_sock()/bh_unlock_sock() pair to three spots.
(BH already disabled)

1) skb_tstamp_tx()
2) Before calling ip_icmp_error(), in __udp4_lib_err()
3) Before calling ipv6_icmp_error(), in __udp6_lib_err()

Reported-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: 单卫 <shanwei88@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/core/skbuff.c | 4 ++++
 net/ipv4/udp.c    | 2 ++
 net/ipv6/udp.c    | 6 ++++--
 3 files changed, 10 insertions(+), 2 deletions(-)

(limited to 'net')

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a807f8c53fb..50a85e31bf6 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3008,7 +3008,11 @@ void skb_tstamp_tx(struct sk_buff *orig_skb,
 	memset(serr, 0, sizeof(*serr));
 	serr->ee.ee_errno = ENOMSG;
 	serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;
+
+	bh_lock_sock(sk);
 	err = sock_queue_err_skb(sk, skb);
+	bh_unlock_sock(sk);
+
 	if (err)
 		kfree_skb(skb);
 }
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 0ac88332d56..4a7fd783f98 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -441,7 +441,9 @@ void __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
 		if (!harderr || sk->sk_state != TCP_ESTABLISHED)
 			goto out;
 	} else {
+		bh_lock_sock(sk);
 		ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
+		bh_unlock_sock(sk);
 	}
 	sk->sk_err = err;
 	sk->sk_error_report(sk);
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 9cc6289acae..12d8791daf9 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -337,9 +337,11 @@ void __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
 	if (sk->sk_state != TCP_ESTABLISHED && !np->recverr)
 		goto out;
 
-	if (np->recverr)
+	if (np->recverr) {
+		bh_lock_sock(sk);
 		ipv6_icmp_error(sk, skb, err, uh->dest, ntohl(info), (u8 *)(uh+1));
-
+		bh_unlock_sock(sk);
+	}
 	sk->sk_err = err;
 	sk->sk_error_report(sk);
 out:
-- 
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