netlink: don't send NETLINK_URELEASE for unbound sockets

Browse source

commit e272602039 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 <dima@ubnt.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Dmitry Ivanov 2016-04-07 09:31:38 +02:00 • committed by Greg Kroah-Hartman

parent 56b8eaa38b

commit 95415ac578

1 changed files with 1 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

net/netlink/af_netlink.c

View file