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Subject[28/75] SELinux: Fix RCU deref check warning in sel_netport_insert()
3.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: David Howells <dhowells@redhat.com>

commit 50345f1ea9cda4618d9c26e590a97ecd4bc7ac75 upstream.

Fix the following bug in sel_netport_insert() where rcu_dereference() should
be rcu_dereference_protected() as sel_netport_lock is held.

===================================================
[ INFO: suspicious rcu_dereference_check() usage. ]
---------------------------------------------------
security/selinux/netport.c:127 invoked rcu_dereference_check() without protection!

other info that might help us debug this:

rcu_scheduler_active = 1, debug_locks = 0
1 lock held by ossec-rootcheck/3323:
#0: (sel_netport_lock){+.....}, at: [<ffffffff8117d775>] sel_netport_sid+0xbb/0x226

stack backtrace:
Pid: 3323, comm: ossec-rootcheck Not tainted 3.1.0-rc8-fsdevel+ #1095
Call Trace:
[<ffffffff8105cfb7>] lockdep_rcu_dereference+0xa7/0xb0
[<ffffffff8117d871>] sel_netport_sid+0x1b7/0x226
[<ffffffff8117d6ba>] ? sel_netport_avc_callback+0xbc/0xbc
[<ffffffff8117556c>] selinux_socket_bind+0x115/0x230
[<ffffffff810a5388>] ? might_fault+0x4e/0x9e
[<ffffffff810a53d1>] ? might_fault+0x97/0x9e
[<ffffffff81171cf4>] security_socket_bind+0x11/0x13
[<ffffffff812ba967>] sys_bind+0x56/0x95
[<ffffffff81380dac>] ? sysret_check+0x27/0x62
[<ffffffff8105b767>] ? trace_hardirqs_on_caller+0x11e/0x155
[<ffffffff81076fcd>] ? audit_syscall_entry+0x17b/0x1ae
[<ffffffff811b5eae>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff81380d7b>] system_call_fastpath+0x16/0x1b

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paul Moore <paul@paul-moore.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: James Morris <jmorris@namei.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
security/selinux/netport.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/security/selinux/netport.c
+++ b/security/selinux/netport.c
@@ -123,7 +123,9 @@ static void sel_netport_insert(struct se
if (sel_netport_hash[idx].size == SEL_NETPORT_HASH_BKT_LIMIT) {
struct sel_netport *tail;
tail = list_entry(
- rcu_dereference(sel_netport_hash[idx].list.prev),
+ rcu_dereference_protected(
+ sel_netport_hash[idx].list.prev,
+ lockdep_is_held(&sel_netport_lock)),
struct sel_netport, list);
list_del_rcu(&tail->list);
kfree_rcu(tail, rcu);



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