[PATCH] selinux: fix selinux_netlbl_inode_permission() locking

do not call a sleeping lock API in an RCU read section.
lock_sock_nested can sleep, its BH counterpart doesn't.
selinux_netlbl_inode_permission() needs to use the BH counterpart
unconditionally.

Compile tested.

From: Ingo Molnar <mingo@elte.hu>

added BH disabling, because this function can be called from non-atomic
contexts too, so a naked bh_lock_sock() would be deadlock-prone.

Boot-tested the resulting kernel.

Signed-off-by: Parag Warudkar <paragw@paragw.zapto.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index bdb7070dd3dc..ee0581557966 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2660,9 +2660,11 @@ int selinux_netlbl_inode_permission(struct inode *inode, int mask)
                 rcu_read_unlock();
                 return 0;
         }
-        lock_sock(sock->sk);
+        local_bh_disable();
+        bh_lock_sock_nested(sock->sk);
         rc = selinux_netlbl_socket_setsid(sock, sksec->sid);
-        release_sock(sock->sk);
+        bh_unlock_sock(sock->sk);
+        local_bh_enable();
         rcu_read_unlock();
 
         return rc;