diff options
| author | Michal Kubeček <mkubecek@suse.cz> | 2015-03-23 15:14:00 +0100 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-04-27 16:48:23 -0400 |
| commit | b9a91574adb307476738fc991d6fbc2c0ac04779 (patch) | |
| tree | 22b8467a415ed56812b3f3f7c7913592e39ecc2d /net | |
| parent | 1ba15e10857b9186b491d3ee20cb98fe675034b5 (diff) | |
tcp: prevent fetching dst twice in early demux code
[ Upstream commit d0c294c53a771ae7e84506dfbd8c18c30f078735 ]
On s390x, gcc 4.8 compiles this part of tcp_v6_early_demux()
struct dst_entry *dst = sk->sk_rx_dst;
if (dst)
dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie);
to code reading sk->sk_rx_dst twice, once for the test and once for
the argument of ip6_dst_check() (dst_check() is inline). This allows
ip6_dst_check() to be called with null first argument, causing a crash.
Protect sk->sk_rx_dst access by READ_ONCE() both in IPv4 and IPv6
TCP early demux code.
Fixes: 41063e9dd119 ("ipv4: Early TCP socket demux.")
Fixes: c7109986db3c ("ipv6: Early TCP socket demux")
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'net')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 2 | ||||
| -rw-r--r-- | net/ipv6/tcp_ipv6.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index 944ce5edbfb7..a5fdfe9fa542 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -1514,7 +1514,7 @@ void tcp_v4_early_demux(struct sk_buff *skb) skb->sk = sk; skb->destructor = sock_edemux; if (sk->sk_state != TCP_TIME_WAIT) { - struct dst_entry *dst = sk->sk_rx_dst; + struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); if (dst) dst = dst_check(dst, 0); diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c index c1136022d8d9..3d60752ec5e3 100644 --- a/net/ipv6/tcp_ipv6.c +++ b/net/ipv6/tcp_ipv6.c @@ -1581,7 +1581,7 @@ static void tcp_v6_early_demux(struct sk_buff *skb) skb->sk = sk; skb->destructor = sock_edemux; if (sk->sk_state != TCP_TIME_WAIT) { - struct dst_entry *dst = sk->sk_rx_dst; + struct dst_entry *dst = READ_ONCE(sk->sk_rx_dst); if (dst) dst = dst_check(dst, inet6_sk(sk)->rx_dst_cookie); |