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authorEric Dumazet <edumazet@google.com>2015-01-21 14:45:42 +0300
committerDavid S. Miller <davem@davemloft.net>2015-01-26 11:44:08 +0300
commit1dc7b90f7cd050ef6d5e511e652347e52874469c (patch)
tree5362ed5e14526d303ba83fc1f596f69fb63933ba /net/ipv6/ipv6_sockglue.c
parent607954b084d4ad5e6a2e0f795de7803d9c6ae37f (diff)
downloadlinux-1dc7b90f7cd050ef6d5e511e652347e52874469c.tar.xz
ipv6: tcp: fix race in IPV6_2292PKTOPTIONS
IPv6 TCP sockets store in np->pktoptions skbs, and use skb_set_owner_r() to charge the skb to socket. It means that destructor must be called while socket is locked. Therefore, we cannot use skb_get() or atomic_inc(&skb->users) to protect ourselves : kfree_skb() might race with other users manipulating sk->sk_forward_alloc Fix this race by holding socket lock for the duration of ip6_datagram_recv_ctl() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/ipv6_sockglue.c')
-rw-r--r--net/ipv6/ipv6_sockglue.c8
1 files changed, 2 insertions, 6 deletions
diff --git a/net/ipv6/ipv6_sockglue.c b/net/ipv6/ipv6_sockglue.c
index 66980d8d98d1..8d766d9100cb 100644
--- a/net/ipv6/ipv6_sockglue.c
+++ b/net/ipv6/ipv6_sockglue.c
@@ -996,13 +996,9 @@ static int do_ipv6_getsockopt(struct sock *sk, int level, int optname,
lock_sock(sk);
skb = np->pktoptions;
if (skb)
- atomic_inc(&skb->users);
- release_sock(sk);
-
- if (skb) {
ip6_datagram_recv_ctl(sk, &msg, skb);
- kfree_skb(skb);
- } else {
+ release_sock(sk);
+ if (!skb) {
if (np->rxopt.bits.rxinfo) {
struct in6_pktinfo src_info;
src_info.ipi6_ifindex = np->mcast_oif ? np->mcast_oif :