xnu-1699.22.73.tar.gz

[apple/xnu.git] / bsd / kern / kern_priv.c

diff --git a/bsd/kern/kern_priv.c b/bsd/kern/kern_priv.c
new file mode 100644 (file)
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+++ b/bsd/kern/kern_priv.c
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+/*
+ * Copyright (c) 2010 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ * 
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ * 
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ * 
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ * 
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
+ */
+/*-
+ * Copyright (c) 2006 nCircle Network Security, Inc.
+ * Copyright (c) 2009 Robert N. M. Watson
+ * All rights reserved.
+ *
+ * This software was developed by Robert N. M. Watson for the TrustedBSD
+ * Project under contract to nCircle Network Security, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR, NCIRCLE NETWORK SECURITY,
+ * INC., OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
+ * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/priv.h>
+#include <sys/proc.h>
+#include <sys/systm.h>
+#include <sys/kauth.h>
+
+#if CONFIG_MACF
+#include <security/mac_framework.h>
+#endif
+
+/*
+ * Check a credential for privilege.  Lots of good reasons to deny privilege;
+ * only a few to grant it.
+ */
+int
+priv_check_cred(kauth_cred_t cred, int priv, __unused int flags)
+{
+       int error;
+
+       /*
+        * We first evaluate policies that may deny the granting of
+        * privilege unilaterally.
+        */
+#if CONFIG_MACF
+       error = mac_priv_check(cred, priv);
+       if (error)
+               goto out;
+#endif
+
+       /*
+        * Having determined if privilege is restricted by various policies,
+        * now determine if privilege is granted.  At this point, any policy
+        * may grant privilege.  For now, we allow short-circuit boolean
+        * evaluation, so may not call all policies.  Perhaps we should.
+        */
+       if (kauth_cred_getuid(cred) == 0) {
+               error = 0;
+               goto out;
+       }
+
+       /*
+        * Now check with MAC, if enabled, to see if a policy module grants
+        * privilege.
+        */
+#if CONFIG_MACF
+       if (mac_priv_grant(cred, priv) == 0) {
+               error = 0;
+               goto out;
+       }
+#endif
+
+       /*
+        * The default is deny, so if no policies have granted it, reject
+        * with a privilege error here.
+        */
+       error = EPERM;
+out:
+       return (error);
+}