[ 80/83] selinux: fix sel_netnode_insert() suspicious rcu dereference
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2012-11-22 18:40:14
Also in:
lkml
3.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Dave Jones <redacted>
commit 88a693b5c1287be4da937699cb82068ce9db0135 upstream.
===============================
[ INFO: suspicious RCU usage. ]
3.5.0-rc1+ #63 Not tainted
-------------------------------
security/selinux/netnode.c:178 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 1, debug_locks = 0
1 lock held by trinity-child1/8750:
#0: (sel_netnode_lock){+.....}, at: [<ffffffff812d8f8a>] sel_netnode_sid+0x16a/0x3e0
stack backtrace:
Pid: 8750, comm: trinity-child1 Not tainted 3.5.0-rc1+ #63
Call Trace:
[<ffffffff810cec2d>] lockdep_rcu_suspicious+0xfd/0x130
[<ffffffff812d91d1>] sel_netnode_sid+0x3b1/0x3e0
[<ffffffff812d8e20>] ? sel_netnode_find+0x1a0/0x1a0
[<ffffffff812d24a6>] selinux_socket_bind+0xf6/0x2c0
[<ffffffff810cd1dd>] ? trace_hardirqs_off+0xd/0x10
[<ffffffff810cdb55>] ? lock_release_holdtime.part.9+0x15/0x1a0
[<ffffffff81093841>] ? lock_hrtimer_base+0x31/0x60
[<ffffffff812c9536>] security_socket_bind+0x16/0x20
[<ffffffff815550ca>] sys_bind+0x7a/0x100
[<ffffffff816c03d5>] ? sysret_check+0x22/0x5d
[<ffffffff810d392d>] ? trace_hardirqs_on_caller+0x10d/0x1a0
[<ffffffff8133b09e>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<ffffffff816c03a9>] system_call_fastpath+0x16/0x1b
This patch below does what Paul McKenney suggested in the previous thread.
Signed-off-by: Dave Jones <redacted>
Reviewed-by: Paul E. McKenney <redacted>
Acked-by: Paul Moore <paul@paul-moore.com>
Cc: Eric Paris <redacted>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: James Morris <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
security/selinux/netnode.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/security/selinux/netnode.c
+++ b/security/selinux/netnode.c@@ -174,7 +174,8 @@ static void sel_netnode_insert(struct se if (sel_netnode_hash[idx].size == SEL_NETNODE_HASH_BKT_LIMIT) { struct sel_netnode *tail; tail = list_entry( - rcu_dereference(sel_netnode_hash[idx].list.prev), + rcu_dereference_protected(sel_netnode_hash[idx].list.prev, + lockdep_is_held(&sel_netnode_lock)), struct sel_netnode, list); list_del_rcu(&tail->list); kfree_rcu(tail, rcu);