From 56b8eaa38b04f147a6b825a73a31b826b6051604 Mon Sep 17 00:00:00 2001 From: Dmitry Ivanov Date: Wed, 6 Apr 2016 17:23:18 +0300 Subject: nl80211: check netlink protocol in socket release notification commit 8f815cdde3e550e10c2736990d791f60c2ce43eb upstream. A non-privileged user can create a netlink socket with the same port_id as used by an existing open nl80211 netlink socket (e.g. as used by a hostapd process) with a different protocol number. Closing this socket will then lead to the notification going to nl80211's socket release notification handler, and possibly cause an action such as removing a virtual interface. Fix this issue by checking that the netlink protocol is NETLINK_GENERIC. Since generic netlink has no notifier chain of its own, we can't fix the problem more generically. Fixes: 026331c4d9b5 ("cfg80211/mac80211: allow registering for and sending action frames") Signed-off-by: Dmitry Ivanov [rewrite commit message] Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/wireless/nl80211.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net') diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index 75b0d23ee882..5d89f13a98db 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -13161,7 +13161,7 @@ static int nl80211_netlink_notify(struct notifier_block * nb, struct wireless_dev *wdev; struct cfg80211_beacon_registration *reg, *tmp; - if (state != NETLINK_URELEASE) + if (state != NETLINK_URELEASE || notify->protocol != NETLINK_GENERIC) return NOTIFY_DONE; rcu_read_lock(); -- cgit v1.2.3 From 95415ac5786f483c7c69145ae644bc64c2240776 Mon Sep 17 00:00:00 2001 From: Dmitry Ivanov Date: Thu, 7 Apr 2016 09:31:38 +0200 Subject: netlink: don't send NETLINK_URELEASE for unbound sockets commit e27260203912b40751fa353d009eaa5a642c739f upstream. All existing users of NETLINK_URELEASE use it to clean up resources that were previously allocated to a socket via some command. As a result, no users require getting this notification for unbound sockets. Sending it for unbound sockets, however, is a problem because any user (including unprivileged users) can create a socket that uses the same ID as an existing socket. Binding this new socket will fail, but if the NETLINK_URELEASE notification is generated for such sockets, the users thereof will be tricked into thinking the socket that they allocated the resources for is closed. In the nl80211 case, this will cause destruction of virtual interfaces that still belong to an existing hostapd process; this is the case that Dmitry noticed. In the NFC case, it will cause a poll abort. In the case of netlink log/queue it will cause them to stop reporting events, as if NFULNL_CFG_CMD_UNBIND/NFQNL_CFG_CMD_UNBIND had been called. Fix this problem by checking that the socket is bound before generating the NETLINK_URELEASE notification. Signed-off-by: Dmitry Ivanov Signed-off-by: Johannes Berg Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/netlink/af_netlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'net') diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 59651af8cc27..992b35fb8615 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -1305,7 +1305,7 @@ static int netlink_release(struct socket *sock) skb_queue_purge(&sk->sk_write_queue); - if (nlk->portid) { + if (nlk->portid && nlk->bound) { struct netlink_notify n = { .net = sock_net(sk), .protocol = sk->sk_protocol, -- cgit v1.2.3 From 03d86237007729b006808e8eab90e96a565deee4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Fri, 4 Mar 2016 17:20:13 +1100 Subject: sunrpc/cache: drop reference when sunrpc_cache_pipe_upcall() detects a race commit a6ab1e8126d205238defbb55d23661a3a5c6a0d8 upstream. sunrpc_cache_pipe_upcall() can detect a race if CACHE_PENDING is no longer set. In this case it aborts the queuing of the upcall. However it has already taken a new counted reference on "h" and doesn't "put" it, even though it frees the data structure holding the reference. So let's delay the "cache_get" until we know we need it. Fixes: f9e1aedc6c79 ("sunrpc/cache: remove races with queuing an upcall.") Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/cache.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c index 21e20353178e..63fb5ee212cf 100644 --- a/net/sunrpc/cache.c +++ b/net/sunrpc/cache.c @@ -1182,14 +1182,14 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h) } crq->q.reader = 0; - crq->item = cache_get(h); crq->buf = buf; crq->len = 0; crq->readers = 0; spin_lock(&queue_lock); - if (test_bit(CACHE_PENDING, &h->flags)) + if (test_bit(CACHE_PENDING, &h->flags)) { + crq->item = cache_get(h); list_add_tail(&crq->q.list, &detail->queue); - else + } else /* Lost a race, no longer PENDING, so don't enqueue */ ret = -EAGAIN; spin_unlock(&queue_lock); -- cgit v1.2.3