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0c06bea919
peernet2id_alloc() is racy without rtnl_lock() as refcount_read(&peer->count)
under net->nsid_lock does not guarantee, peer is alive:
rcu_read_lock()
peernet2id_alloc() ..
spin_lock_bh(&net->nsid_lock) ..
refcount_read(&peer->count) (!= 0) ..
.. put_net()
.. cleanup_net()
.. for_each_net(tmp)
.. spin_lock_bh(&tmp->nsid_lock)
.. __peernet2id(tmp, net) == -1
.. ..
.. ..
__peernet2id_alloc(alloc == true) ..
.. ..
rcu_read_unlock() ..
.. synchronize_rcu()
.. kmem_cache_free(net)
After the above situation, net::netns_id contains id pointing to freed memory,
and any other dereferencing by the id will operate with this freed memory.
Currently, peernet2id_alloc() is used under rtnl_lock() everywhere except
ovs_vport_cmd_fill_info(), and this race can't occur. But peernet2id_alloc()
is generic interface, and better we fix it before someone really starts
use it in wrong context.
v2: Don't place refcount_read(&net->count) under net->nsid_lock
as suggested by Eric W. Biederman <ebiederm@xmission.com>
v3: Rebase on top of net-next
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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| .. | ||
| datagram.c | ||
| dev_addr_lists.c | ||
| dev_ioctl.c | ||
| dev.c | ||
| devlink.c | ||
| drop_monitor.c | ||
| dst_cache.c | ||
| dst.c | ||
| ethtool.c | ||
| fib_notifier.c | ||
| fib_rules.c | ||
| filter.c | ||
| flow_dissector.c | ||
| gen_estimator.c | ||
| gen_stats.c | ||
| gro_cells.c | ||
| hwbm.c | ||
| link_watch.c | ||
| lwt_bpf.c | ||
| lwtunnel.c | ||
| Makefile | ||
| neighbour.c | ||
| net_namespace.c | ||
| net-procfs.c | ||
| net-sysfs.c | ||
| net-sysfs.h | ||
| net-traces.c | ||
| netclassid_cgroup.c | ||
| netevent.c | ||
| netpoll.c | ||
| netprio_cgroup.c | ||
| pktgen.c | ||
| ptp_classifier.c | ||
| request_sock.c | ||
| rtnetlink.c | ||
| scm.c | ||
| secure_seq.c | ||
| skbuff.c | ||
| sock_diag.c | ||
| sock_reuseport.c | ||
| sock.c | ||
| stream.c | ||
| sysctl_net_core.c | ||
| timestamping.c | ||
| tso.c | ||
| utils.c | ||
| xdp.c | ||