From 42d64e1add3a1ce8a787116036163b8724362145 Mon Sep 17 00:00:00 2001 From: Paul Moore Date: Thu, 26 Sep 2013 17:00:46 -0400 Subject: [PATCH] selinux: correct locking in selinux_netlbl_socket_connect) The SELinux/NetLabel glue code has a locking bug that affects systems with NetLabel enabled, see the kernel error message below. This patch corrects this problem by converting the bottom half socket lock to a more conventional, and correct for this call-path, lock_sock() call. =============================== [ INFO: suspicious RCU usage. ] 3.11.0-rc3+ #19 Not tainted ------------------------------- net/ipv4/cipso_ipv4.c:1928 suspicious rcu_dereference_protected() usage! other info that might help us debug this: rcu_scheduler_active = 1, debug_locks = 0 2 locks held by ping/731: #0: (slock-AF_INET/1){+.-...}, at: [...] selinux_netlbl_socket_connect #1: (rcu_read_lock){.+.+..}, at: [<...>] netlbl_conn_setattr stack backtrace: CPU: 1 PID: 731 Comm: ping Not tainted 3.11.0-rc3+ #19 Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 0000000000000001 ffff88006f659d28 ffffffff81726b6a ffff88003732c500 ffff88006f659d58 ffffffff810e4457 ffff88006b845a00 0000000000000000 000000000000000c ffff880075aa2f50 ffff88006f659d90 ffffffff8169bec7 Call Trace: [] dump_stack+0x54/0x74 [] lockdep_rcu_suspicious+0xe7/0x120 [] cipso_v4_sock_setattr+0x187/0x1a0 [] netlbl_conn_setattr+0x187/0x190 [] ? netlbl_conn_setattr+0x5/0x190 [] selinux_netlbl_socket_connect+0xae/0xc0 [] selinux_socket_connect+0x135/0x170 [] ? might_fault+0x57/0xb0 [] security_socket_connect+0x16/0x20 [] SYSC_connect+0x73/0x130 [] ? sysret_check+0x22/0x5d [] ? trace_hardirqs_on_caller+0xfd/0x1c0 [] ? trace_hardirqs_on_thunk+0x3a/0x3f [] SyS_connect+0xe/0x10 [] system_call_fastpath+0x16/0x1b Cc: stable@vger.kernel.org Signed-off-by: Paul Moore --- security/selinux/netlabel.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/security/selinux/netlabel.c b/security/selinux/netlabel.c index da4b8b233280..6235d052338b 100644 --- a/security/selinux/netlabel.c +++ b/security/selinux/netlabel.c @@ -442,8 +442,7 @@ int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr) sksec->nlbl_state != NLBL_CONNLABELED) return 0; - local_bh_disable(); - bh_lock_sock_nested(sk); + lock_sock(sk); /* connected sockets are allowed to disconnect when the address family * is set to AF_UNSPEC, if that is what is happening we want to reset @@ -464,7 +463,6 @@ int selinux_netlbl_socket_connect(struct sock *sk, struct sockaddr *addr) sksec->nlbl_state = NLBL_CONNLABELED; socket_connect_return: - bh_unlock_sock(sk); - local_bh_enable(); + release_sock(sk); return rc; }