On Wednesday, October 05, 2011 12:19:19 PM David Howells wrote:
> 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@xxxxxxxxxx>
> ---
>
> security/selinux/netport.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
Acked-by: Paul Moore <paul@xxxxxxxxxxxxxx>
> diff --git a/security/selinux/netport.c b/security/selinux/netport.c
> index 0b62bd1..7b9eb1f 100644
> --- a/security/selinux/netport.c
> +++ b/security/selinux/netport.c
> @@ -123,7 +123,9 @@ static void sel_netport_insert(struct sel_netport *port)
> 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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--
paul moore
www.paul-moore.com
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