mcs/class/corlib/CommonCrypto/CommonCrypto.cs

   1 // CommonCrypto bindings for MonoMac and MonoTouch
   2 //
   3 // Authors:
   4 //      Sebastien Pouliot  <sebastien@xamarin.com>
   5 //
   6 // Copyright 2012-2014 Xamarin Inc.
   7
   8 using System;
   9 using System.Security.Cryptography;
  10 using System.Runtime.InteropServices;
  11
  12 namespace Crimson.CommonCrypto {
  13
  14         // int32_t -> CommonCryptor.h
  15         enum CCCryptorStatus {
  16             Success                     = 0,
  17         ParamError              = -4300,
  18             BufferTooSmall      = -4301,
  19         MemoryFailure   = -4302,
  20         AlignmentError  = -4303,
  21         DecodeError             = -4304,
  22         Unimplemented   = -4305
  23         }
  24
  25         // uint32_t -> CommonCryptor.h
  26         // note: not exposed publicly so it can stay signed
  27         enum CCOperation {
  28                 Encrypt = 0,
  29                 Decrypt,
  30         }
  31
  32         // uint32_t -> CommonCryptor.h
  33         // note: not exposed publicly so it can stay signed
  34         enum CCAlgorithm {
  35                 AES128 = 0,
  36                 DES,
  37                 TripleDES,
  38                 CAST,
  39                 RC4,
  40                 RC2,
  41                 Blowfish
  42         }
  43
  44         // uint32_t -> CommonCryptor.h
  45         // note: not exposed publicly so it can stay signed
  46         [Flags]
  47         enum CCOptions {
  48                 None                    = 0,
  49                 PKCS7Padding    = 1,
  50                 ECBMode                 = 2
  51         }
  52
  53         static class Cryptor {
  54
  55                 const string libSystem = "/usr/lib/libSystem.dylib";
  56
  57                 // size_t was changed to IntPtr for 32/64 bits size difference - even if mono is (moslty) used in 32bits only on OSX today
  58                 // not using `nint` to be able to resue this outside (if needed)
  59
  60                 [DllImport (libSystem)]
  61                 extern internal static CCCryptorStatus CCCryptorCreate (CCOperation op, CCAlgorithm alg, CCOptions options, /* const void* */ byte[] key, /* size_t */ IntPtr keyLength, /* const void* */ byte[] iv, /* CCCryptorRef* */ ref IntPtr cryptorRef);
  62
  63                 [DllImport (libSystem)]
  64                 extern internal static CCCryptorStatus CCCryptorRelease (/* CCCryptorRef */ IntPtr cryptorRef);
  65
  66                 [DllImport (libSystem)]
  67                 extern internal static CCCryptorStatus CCCryptorUpdate (/* CCCryptorRef */ IntPtr cryptorRef, /* const void* */ byte[] dataIn, /* size_t */ IntPtr dataInLength, /* void* */ byte[] dataOut, /* size_t */ IntPtr dataOutAvailable, /* size_t* */ ref IntPtr dataOutMoved);
  68
  69                 [DllImport (libSystem)]
  70                 extern internal static CCCryptorStatus CCCryptorUpdate (/* CCCryptorRef */ IntPtr cryptorRef, /* const void* */ IntPtr dataIn, /* size_t */ IntPtr dataInLength, /* void* */ IntPtr dataOut, /* size_t */ IntPtr dataOutAvailable, /* size_t* */ ref IntPtr dataOutMoved);
  71
  72                 [DllImport (libSystem)]
  73                 extern internal static CCCryptorStatus CCCryptorFinal (/* CCCryptorRef */ IntPtr cryptorRef, /* void* */ byte[] dataOut, /* size_t */ IntPtr dataOutAvailable, /* size_t* */ ref IntPtr dataOutMoved);
  74
  75                 [DllImport (libSystem)]
  76                 extern internal static int CCCryptorGetOutputLength (/* CCCryptorRef */ IntPtr cryptorRef, /* size_t */ IntPtr inputLength, bool final);
  77
  78                 [DllImport (libSystem)]
  79                 extern internal static CCCryptorStatus CCCryptorReset (/* CCCryptorRef */ IntPtr cryptorRef, /* const void* */ IntPtr iv);
  80
  81                 // helper method to reduce the amount of generate code for each cipher algorithm
  82                 static internal IntPtr Create (CCOperation operation, CCAlgorithm algorithm, CCOptions options, byte[] key, byte[] iv)
  83                 {
  84                         if (key == null)
  85                                 throw new CryptographicException ("A null key was provided");
  86
  87                         // unlike the .NET framework CommonCrypto does not support two-keys triple-des (128 bits) ref: #6967
  88                         if ((algorithm == CCAlgorithm.TripleDES) && (key.Length == 16)) {
  89                                 byte[] key3 = new byte [24];
  90                                 Buffer.BlockCopy (key, 0, key3, 0, 16);
  91                                 Buffer.BlockCopy (key, 0, key3, 16, 8);
  92                                 key = key3;
  93                         }
  94
  95                         IntPtr cryptor = IntPtr.Zero;
  96                         CCCryptorStatus status = Cryptor.CCCryptorCreate (operation, algorithm, options, key, (IntPtr) key.Length, iv, ref cryptor);
  97                         if (status != CCCryptorStatus.Success)
  98                                 throw new CryptographicUnexpectedOperationException ();
  99                         return cryptor;
 100                 }
 101
 102                 // size_t was changed to IntPtr for 32/64 bits size difference - even if mono is (moslty) used in 32bits only on OSX today
 103                 [DllImport ("/System/Library/Frameworks/Security.framework/Security")]
 104                 extern internal static /* int */ int SecRandomCopyBytes (/* SecRandomRef */ IntPtr rnd, /* size_t */ IntPtr count, /* uint8_t* */ byte[] bytes);
 105
 106                 static internal void GetRandom (byte[] buffer)
 107                 {
 108                         if (SecRandomCopyBytes (IntPtr.Zero, (IntPtr) buffer.Length, buffer) != 0)
 109                                 throw new CryptographicException (Marshal.GetLastWin32Error ()); // errno
 110                 }
 111         }
 112
 113 #if !MONOTOUCH && !XAMMAC
 114         static class KeyBuilder {
 115                 static public byte[] Key (int size)
 116                 {
 117                         byte[] buffer = new byte [size];
 118                         Cryptor.GetRandom (buffer);
 119                         return buffer;
 120                 }
 121
 122                 static public byte[] IV (int size)
 123                 {
 124                         byte[] buffer = new byte [size];
 125                         Cryptor.GetRandom (buffer);
 126                         return buffer;
 127                 }
 128         }
 129 #endif
 130 }