/*
 * Copyright 2000, International Business Machines Corporation and others.
 * All Rights Reserved.
 * 
 * This software has been released under the terms of the IBM Public
 * License.  For details, see the LICENSE file in the top-level source
 * directory or online at http://www.openafs.org/dl/license10.html
 */

/* Security related utilities for the Windows platform */

#include <afs/param.h>
#include <afsconfig.h>


#include <afs/stds.h>

#include <stddef.h>
#include <stdlib.h>
#include <errno.h>

#include <windows.h>
#include <aclapi.h>

#include "secutil_nt.h"



/* local declarations */

static BOOL WorldGroupSidAllocate(PSID * sidPP);

static BOOL LocalAdminsGroupSidAllocate(PSID * sidPP);

static void
  BuildExplicitAccessWithSid(PEXPLICIT_ACCESS explicitAccessP,
			     PSID trusteeSidP, DWORD accessPerm,
			     ACCESS_MODE accessMode, DWORD inheritance);



/* --------------------  Exported functions ------------------------ */



/*
 * ObjectDaclEntryAdd() -- add an access-control entry to an object's DACL.
 *
 *     Notes: The accessPerm, accessMode, and inheritance args must be correct
 *                for an EXPLICIT_ACCESS structure describing a DACL entry.
 *            Caller must have READ_CONTRL/WRITE_DAC rights for object handle.
 *
 * RETURN CODES: Win32 status code (ERROR_SUCCESS if succeeds)
 */
DWORD
ObjectDaclEntryAdd(HANDLE objectHandle, SE_OBJECT_TYPE objectType,
		   WELLKNOWN_TRUSTEE_ID trustee, DWORD accessPerm,
		   ACCESS_MODE accessMode, DWORD inheritance)
{
    DWORD status = ERROR_SUCCESS;
    PSID trusteeSidP;

    /* allocate SID for (well-known) trustee */

    if (trustee == WorldGroup) {
	if (!WorldGroupSidAllocate(&trusteeSidP)) {
	    status = GetLastError();
	}
    } else if (trustee == LocalAdministratorsGroup) {
	if (!LocalAdminsGroupSidAllocate(&trusteeSidP)) {
	    status = GetLastError();
	}
    } else {
	status = ERROR_INVALID_PARAMETER;
    }

    if (status == ERROR_SUCCESS) {
	EXPLICIT_ACCESS accessEntry;
	PACL curDaclP, newDaclP;
	PSECURITY_DESCRIPTOR secP;

	/* initialize access information for trustee */

	BuildExplicitAccessWithSid(&accessEntry, trusteeSidP, accessPerm,
				   accessMode, inheritance);

	/* get object's current DACL */

	status =
	    GetSecurityInfo(objectHandle, objectType,
			    DACL_SECURITY_INFORMATION, NULL, NULL, &curDaclP,
			    NULL, &secP);

	if (status == ERROR_SUCCESS) {
	    /* merge access information into current DACL to form new DACL */
	    status = SetEntriesInAcl(1, &accessEntry, curDaclP, &newDaclP);

	    if (status == ERROR_SUCCESS) {
		/* replace object's current DACL with newly formed DACL */

		/* MS SP4 introduced a bug into SetSecurityInfo() so that it
		 * no longer operates correctly with named pipes.  Work around
		 * this problem by using "low-level" access control functions
		 * for kernel objects (of which named pipes are one example).
		 */

		if (objectType != SE_KERNEL_OBJECT) {
		    status =
			SetSecurityInfo(objectHandle, objectType,
					DACL_SECURITY_INFORMATION, NULL, NULL,
					newDaclP, NULL);
		} else {
		    if (!SetSecurityDescriptorDacl
			(secP, TRUE, newDaclP, FALSE)
			|| !SetKernelObjectSecurity(objectHandle,
						    DACL_SECURITY_INFORMATION,
						    secP)) {
			status = GetLastError();
		    }
		}

		(void)LocalFree((HLOCAL) newDaclP);
	    }

	    (void)LocalFree((HLOCAL) secP);
	}

	FreeSid(trusteeSidP);
    }

    return status;
}




/* --------------------  Local functions ------------------------ */

/*
 * WorldGroupSidAllocate() -- allocate and initialize SID for the
 *     well-known World group representing all users.
 *
 *     SID is freed via FreeSid()
 *
 * RETURN CODES: TRUE success, FALSE failure  (GetLastError() indicates why)
 */
static BOOL
WorldGroupSidAllocate(PSID * sidPP)
{
    SID_IDENTIFIER_AUTHORITY sidAuth = SECURITY_WORLD_SID_AUTHORITY;

    return AllocateAndInitializeSid(&sidAuth, 1, SECURITY_WORLD_RID, 0, 0, 0,
				    0, 0, 0, 0, sidPP);
}


/*
 * LocalAdminsGroupSidAllocate() -- allocate and initialize SID for the
 *     well-known local Administrators group.
 *
 *     SID is freed via FreeSid()
 *
 * RETURN CODES: TRUE success, FALSE failure  (GetLastError() indicates why)
 */
static BOOL
LocalAdminsGroupSidAllocate(PSID * sidPP)
{
    SID_IDENTIFIER_AUTHORITY sidAuth = SECURITY_NT_AUTHORITY;

    return AllocateAndInitializeSid(&sidAuth, 2, SECURITY_BUILTIN_DOMAIN_RID,
				    DOMAIN_ALIAS_RID_ADMINS, 0, 0, 0, 0, 0, 0,
				    sidPP);
}


/*
 * BuildExplicitAccessWithSid() - counterpart to the Win32 API function
 *     BuildExplicitAccessWithName() (surprisingly, MS doesn't provide this).
 */
static void
BuildExplicitAccessWithSid(PEXPLICIT_ACCESS explicitAccessP, PSID trusteeSidP,
			   DWORD accessPerm, ACCESS_MODE accessMode,
			   DWORD inheritance)
{
    if (explicitAccessP != NULL) {
	explicitAccessP->grfAccessPermissions = accessPerm;
	explicitAccessP->grfAccessMode = accessMode;
	explicitAccessP->grfInheritance = inheritance;
	BuildTrusteeWithSid(&explicitAccessP->Trustee, trusteeSidP);
    }
}
