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authorJesse Gross <jesse@nicira.com>2014-12-16 18:25:32 -0800
committerDavid S. Miller <davem@davemloft.net>2014-12-18 12:38:13 -0500
commit12069401d895ff84076a50189ca842c0696b84b2 (patch)
treed93c1ec4635a9d2d64fff54d376e40da3a72e13e
parent7ed767f73192d6daf673c6d885cd02d5f280ac1f (diff)
geneve: Fix races between socket add and release.
Currently, searching for a socket to add a reference to is not synchronized with deletion of sockets. This can result in use after free if there is another operation that is removing a socket at the same time. Solving this requires both holding the appropriate lock and checking the refcount to ensure that it has not already hit zero. Inspired by a related (but not exactly the same) issue in the VXLAN driver. Fixes: 0b5e8b8e ("net: Add Geneve tunneling protocol driver") CC: Andy Zhou <azhou@nicira.com> Signed-off-by: Jesse Gross <jesse@nicira.com> Acked-by: Thomas Graf <tgraf@suug.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--net/ipv4/geneve.c13
1 files changed, 7 insertions, 6 deletions
diff --git a/net/ipv4/geneve.c b/net/ipv4/geneve.c
index 5a47188b01e9..95e47c97585e 100644
--- a/net/ipv4/geneve.c
+++ b/net/ipv4/geneve.c
@@ -296,6 +296,7 @@ struct geneve_sock *geneve_sock_add(struct net *net, __be16 port,
geneve_rcv_t *rcv, void *data,
bool no_share, bool ipv6)
{
+ struct geneve_net *gn = net_generic(net, geneve_net_id);
struct geneve_sock *gs;
gs = geneve_socket_create(net, port, rcv, data, ipv6);
@@ -305,15 +306,15 @@ struct geneve_sock *geneve_sock_add(struct net *net, __be16 port,
if (no_share) /* Return error if sharing is not allowed. */
return ERR_PTR(-EINVAL);
+ spin_lock(&gn->sock_lock);
gs = geneve_find_sock(net, port);
- if (gs) {
- if (gs->rcv == rcv)
- atomic_inc(&gs->refcnt);
- else
+ if (gs && ((gs->rcv != rcv) ||
+ !atomic_add_unless(&gs->refcnt, 1, 0)))
gs = ERR_PTR(-EBUSY);
- } else {
+ spin_unlock(&gn->sock_lock);
+
+ if (!gs)
gs = ERR_PTR(-EINVAL);
- }
return gs;
}