ipv6: prevent race between address creation and removal
There's a race in IPv6 automatic addess assignment. The address is created
with zero lifetime when it's added to various address lists. Before it gets
assigned the correct lifetime, there's a window where a new address may be
configured. This causes the semi-initiated address to be deleted in
addrconf_verify.
This was discovered as a reference leak caused by concurrent run of
__ipv6_ifa_notify for both RTM_NEWADDR and RTM_DELADDR with the same
address.
Fix this by setting the lifetime before the address is added to
inet6_addr_lst.
A few notes:
1. In addrconf_prefix_rcv, by setting update_lft to zero, the
if (update_lft) { ... } condition is no longer executed for newly
created addresses. This is okay, as the ifp fields are set in
ipv6_add_addr now and ipv6_ifa_notify is called (and has been called)
through addrconf_dad_start.
2. The removal of the whole block under ifp->lock in inet6_addr_add is okay,
too, as tstamp is initialized to jiffies in ipv6_add_addr.
Signed-off-by: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
1 file changed
