[20/21] net: fix sk_forward_alloc corruptions
From: Greg KH <gregkh@linuxfoundation.org>
Date: 2012-02-10 22:53:25
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2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet <redacted> 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 <redacted> Signed-off-by: Eric Dumazet <redacted> Signed-off-by: David S. Miller <davem@davemloft.net> Cc: ������ <redacted> 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(-)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c@@ -3008,7 +3008,11 @@ void skb_tstamp_tx(struct sk_buff *orig_ 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); } --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c
@@ -441,7 +441,9 @@ void __udp4_lib_err(struct sk_buff *skb, 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); --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c
@@ -337,9 +337,11 @@ void __udp6_lib_err(struct sk_buff *skb, 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: