SFAuthorization

SFAuthorization.cs

//
// SFAuthorization.cs
//
// Author:
//   Aaron Bockover <abock@xamarin.com>
//
// Copyright 2017 Microsoft. All rights reserved.

using System;

using Foundation;
using Security;

namespace SecurityFoundation
{
	// @interface SFAuthorization : NSObject <NSCoding>
	[BaseType (typeof (NSObject))]
	interface SFAuthorization : INSCoding
	{
		// +(id)authorization;
		[Static]
		[Export ("authorization")]
		SFAuthorization Authorization { get; }

		// -(AuthorizationRef)authorizationRef;
		// TODO: This should return a `Security.Authorization` instead, but the
		// ref is owned by this `SFAuthorization`. `Security.Authorization` needs
		// a .ctor that does allows the wrapper to not take ownership of the ref.
		[Internal]
		[Export ("authorizationRef")]
		IntPtr AuthorizationRef { get; }

		// +(id)authorizationWithFlags:(AuthorizationFlags)flags rights:(const AuthorizationRights *)rights environment:(const AuthorizationEnvironment *)environment;
		[Static]
		[Internal]
		[Export ("authorizationWithFlags:rights:environment:")]
		SFAuthorization AuthorizationWithFlags (AuthorizationFlags flags, IntPtr rights, IntPtr environment);

		// -(id)initWithFlags:(AuthorizationFlags)flags rights:(const AuthorizationRights *)rights environment:(const AuthorizationEnvironment *)environment;
		[Internal]
		[Export ("initWithFlags:rights:environment:")]
		IntPtr Constructor (AuthorizationFlags flags, IntPtr rights, IntPtr environment);

		// -(void)invalidateCredentials;
		[Export ("invalidateCredentials")]
		void InvalidateCredentials ();

		// -(BOOL)obtainWithRight:(AuthorizationString)rightName flags:(AuthorizationFlags)flags error:(NSError **)error;
		[Internal]
		[Export ("obtainWithRight:flags:error:")]
		bool ObtainWithRight (IntPtr rightName, AuthorizationFlags flags, out NSError error);

		// -(BOOL)obtainWithRights:(const AuthorizationRights *)rights flags:(AuthorizationFlags)flags environment:(const AuthorizationEnvironment *)environment authorizedRights:(AuthorizationRights **)authorizedRights error:(NSError **)error;
		[Internal]
		[Export ("obtainWithRights:flags:environment:authorizedRights:error:")]
		bool ObtainWithRights (IntPtr rights, AuthorizationFlags flags, IntPtr environment, IntPtr authorizedRights, out NSError error);
	}
}

SFAuthorization_Extensions.cs

//
// SFAuthorization_Extensions.cs
//
// Author:
//   Aaron Bockover <abock@xamarin.com>
//
// Copyright 2017 Microsoft. All rights reserved.

using System;
using System.Text;
using System.Runtime.InteropServices;

using Foundation;
using Security;

namespace SecurityFoundation
{
	partial class SFAuthorization
	{
		// TODO: wrappers for the other internal rights APIs

		public unsafe void ObtainWithRight (string rightName, AuthorizationFlags flags, out NSError error)
		{
			if (rightName == null)
				throw new ArgumentNullException (nameof (rightName));

			var utf8 = new byte [Encoding.UTF8.GetByteCount (rightName) + 1];
			Encoding.UTF8.GetBytes (rightName, 0, rightName.Length, utf8, 0);

			fixed (byte* utf8Pointer = utf8) {
				if (!ObtainWithRight (new IntPtr (utf8Pointer), flags, out error))
					throw new NSErrorException (error);
			}
		}

		const int kAuthorizationExternalFormLength = 32;

		[DllImport (ObjCRuntime.Constants.SecurityLibrary)]
		static extern int AuthorizationMakeExternalForm (IntPtr authorizationRef, IntPtr extForm);

		// FIXME: there should be a `Security.Authorization.MakeExternalForm`, and this
		// helper should simply exist as `NSData MakeExternalForm () => Authorization.MakeExternalForm ()`;
		// see the note in the `SFAuthorization` binding scaffolding.
		public NSData MakeExternalForm ()
		{
			var extForm = Marshal.AllocHGlobal (kAuthorizationExternalFormLength);
			var result = AuthorizationMakeExternalForm (AuthorizationRef, extForm);
			if (result == 0)
				return NSData.FromBytesNoCopy (extForm, kAuthorizationExternalFormLength, true);

			Marshal.FreeHGlobal (extForm);
			throw new Exception ($"AuthorizationMakeExternalForm returned {result}");
		}
	}
}