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Commit 29030374 authored May 29, 2010 by Eric Dumazet Committed by David S. Miller May 29, 2010

net: fix sk_forward_alloc corruptions



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>

parent 7dfde179

net/core/skbuff.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -2992,7 +2992,11 @@ 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);
		}

net/ipv4/udp.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -634,7 +634,9 @@ 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);

net/ipv6/udp.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -466,9 +466,11 @@ 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: