net: fix sk_forward_alloc corruptions

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>

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index a807f8c53fb5369dcf0de836450a68eeb65a7b09..50a85e31bf61e4af9e730140a167b3e9eaccb746 100644 (file)
--- 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 0ac88332d56a3f52ee8e216f3db9c053ff274176..4a7fd783f9834a91130a2e198e639501a1f0c5b9 100644 (file)
--- 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 9cc6289acaedb235ee93187ec95b8845d202f888..12d8791daf91fcee153ef122f93016aa350d46a5 100644 (file)
--- 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: