/* Copyright (C)  1998  Transarc Corporation.  All rights reserved.
 *
 */

/* Security related utilities for the Windows platform */

#include <param.h>
#include <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);
    }
}