MYCrypto: MYDEREncoder.m@90a70925562b

     1 //

     2 //  MYDEREncoder.m

     3 //  MYCrypto

     4 //

     5 //  Created by Jens Alfke on 5/29/09.

     6 //  Copyright 2009 Jens Alfke. All rights reserved.

     7 //

     9 #import "MYDEREncoder.h"

    10 #import "MYASN1Object.h"

    11 #import "MYBERParser.h"

    12 #import "MYOID.h"

    13 #import "MYErrorUtils.h"

    16 #define MYDEREncoderException @"MYDEREncoderException"

    19 @interface MYDEREncoder ()

    20 - (void) _encode: (id)object;

    21 @property (retain) NSError *error;

    22 @end

    25 @implementation MYDEREncoder

    28 - (id) initWithRootObject: (id)rootObject

    29 {

    30     self = [super init];

    31     if (self != nil) {

    32         _rootObject = [rootObject retain];

    33     }

    34     return self;

    35 }

    37 + (NSData*) encodeRootObject: (id)rootObject error: (NSError**)outError {

    38     MYDEREncoder *encoder = [[self alloc] initWithRootObject: rootObject];

    39     NSData *output = [encoder.output copy];

    40     if (outError) *outError = [[encoder.error retain] autorelease];

    41     [encoder release];

    42     return [output autorelease];

    43 }

    45 - (void) dealloc

    46 {

    47     [_rootObject release];

    48     [_output release];

    49     [super dealloc];

    50 }

    54 static unsigned sizeOfUnsignedInt (UInt64 n) {

    55     unsigned bytes = 0;

    56     for (; n; n >>= 8)

    57         bytes++;

    58     return bytes;

    59 }

    61 static unsigned encodeUnsignedInt (UInt64 n, UInt8 buf[], BOOL padHighBit) {

    62     unsigned size = MAX(1U, sizeOfUnsignedInt(n));

    63     UInt64 bigEndian = NSSwapHostLongLongToBig(n);

    64     const UInt8* src = (UInt8*)&bigEndian + (8-size);

    65     UInt8 *dst = &buf[0];

    66     if (padHighBit && (*src & 0x80)) {

    67         *dst++ = 0;

    68         size++;

    69     }

    70     memcpy(dst, src, size);

    71     return size;

    72 }

    74 static unsigned encodeSignedInt (SInt64 n, UInt8 buf[]) {

    75     if (n >= 0)

    76         return encodeUnsignedInt(n, buf, YES);

    77     else {

    78         unsigned size = MAX(1U, sizeOfUnsignedInt(~n));

    79         UInt64 bigEndian = NSSwapHostLongLongToBig(n);

    80         const UInt8* src = (UInt8*)&bigEndian + (8-size);

    81         UInt8 *dst = &buf[0];

    82         if (!(*src & 0x80)) {

    83             *dst++ = 0xFF;

    84             size++;

    85         }

    86         memcpy(dst, src, size);

    87         return size;

    88     }

    89 }

    92 - (void) _writeTag: (unsigned)tag

    93              class: (unsigned)tagClass

    94        constructed: (BOOL) constructed

    95             length: (size_t)length

    96 {

    97     struct {

    98         unsigned tag            :5;

    99         unsigned isConstructed  :1;

   100         unsigned tagClass       :2;

   101         unsigned length         :7;

   102         unsigned isLengthLong   :1;

   103         UInt8    extraLength[9];

   104     } header;

   105     size_t headerSize = 2;

   107     header.tag = tag;

   108     header.isConstructed = constructed;

   109     header.tagClass = tagClass;

   110     if (length < 128) {

   111         header.isLengthLong = NO;

   112         header.length = length;

   113     } else {

   114         header.isLengthLong = YES;

   115         header.length = encodeUnsignedInt(length, header.extraLength, NO);

   116         headerSize += header.length;

   117     }

   118     [_output appendBytes: &header length: headerSize];

   119 }

   121 - (void) _writeTag: (unsigned)tag

   122              class: (unsigned)tagClass

   123        constructed: (BOOL) constructed

   124              bytes: (const void*)bytes

   125             length: (size_t)length

   126 {

   127     [self _writeTag: tag class: tagClass constructed: constructed length: length];

   128     [_output appendBytes: bytes length: length];

   129 }

   131 - (void) _writeTag: (unsigned)tag

   132              class: (unsigned)tagClass

   133        constructed: (BOOL) constructed

   134               data: (NSData*)data

   135 {

   136     Assert(data);

   137     [self _writeTag: tag class: tagClass constructed: constructed bytes: data.bytes length: data.length];

   138 }

   141 - (void) _encodeNumber: (NSNumber*)number {

   142     // Special-case detection of booleans by pointer equality, because otherwise they appear

   143     // identical to 0 and 1:

   144     if (number==$true || number==$false) {

   145         UInt8 value = number==$true ?0xFF :0x00;

   146         [self _writeTag: 1 class: 0 constructed: NO bytes: &value length: 1];

   147         return;

   148     }

   150     const char *type = number.objCType;

   151     if (strlen(type) == 1) {

   152         switch(type[0]) {

   153             case 'c':

   154             case 'i':

   155             case 's':

   156             case 'l':

   157             case 'q':

   158             {   // Signed integers:

   159                 UInt8 buf[9];

   160                 size_t size = encodeSignedInt(number.longLongValue, buf);

   161                 [self _writeTag: 2 class: 0 constructed: NO bytes: buf length: size];

   162                 return;

   163             }

   164             case 'C':

   165             case 'I':

   166             case 'S':

   167             case 'L':

   168             case 'Q':

   169             {   // Unsigned integers:

   170                 UInt8 buf[9];

   171                 size_t size = encodeUnsignedInt(number.unsignedLongLongValue, buf, YES);

   172                 [self _writeTag: 2 class: 0 constructed: NO bytes: buf length: size];

   173                 return;

   174             }

   175             case 'B':

   176             {   // bool

   177                 UInt8 value = number.boolValue ?0xFF :0x00;

   178                 [self _writeTag: 1 class: 0 constructed: NO bytes: &value length: 1];

   179                 return;

   180             }

   181         }

   182     }

   183     [NSException raise: MYDEREncoderException format: @"Can't DER-encode value %@ (typecode=%s)", number,type];

   184 }

   187 - (void) _encodeString: (NSString*)string {

   188     NSData *data = [string dataUsingEncoding: NSASCIIStringEncoding];

   189     if (data)

   190         [self _writeTag: 19 class: 0 constructed: NO data: data];

   191     else

   192         [self _writeTag: 12 class: 0 constructed: NO data: [string dataUsingEncoding: NSUTF8StringEncoding]];

   193 }

   196 - (void) _encodeBitString: (MYBitString*)bitString {

   197     NSUInteger bitCount = bitString.bitCount;

   198     [self _writeTag: 3 class: 0 constructed: NO length: 1 + (bitCount/8)];

   199     UInt8 unused = (8 - (bitCount % 8)) % 8;

   200     [_output appendBytes: &unused length: 1];

   201     [_output appendBytes: bitString.bits.bytes length: bitCount/8];

   202 }

   204 - (void) _encodeDate: (NSDate*)date {

   205     NSString *dateStr = [MYBERGeneralizedTimeFormatter() stringFromDate: date];

   206     Log(@"Encoded %@ as '%@'",date,dateStr);//TEMP

   207     [self _writeTag: 24 class: 0 constructed: NO data: [dateStr dataUsingEncoding: NSASCIIStringEncoding]];

   208 }

   211 - (void) _encodeCollection: (id)collection tag: (unsigned)tag class: (unsigned)tagClass {

   212     MYDEREncoder *subEncoder = [[[self class] alloc] init];

   213     for (id object in collection)

   214         [subEncoder _encode: object];

   215     [self _writeTag: tag class: tagClass constructed: YES data: subEncoder.output];

   216     [subEncoder release];

   217 }

   220 - (void) _encode: (id)object {

   221     if (!_output)

   222         _output = [[NSMutableData alloc] initWithCapacity: 1024];

   223     if ([object isKindOfClass: [NSNumber class]]) {

   224         [self _encodeNumber: object];

   225     } else if ([object isKindOfClass: [NSData class]]) {

   226         [self _writeTag: 4 class: 0 constructed: NO data: object];

   227     } else if ([object isKindOfClass: [MYBitString class]]) {

   228         [self _encodeBitString: object];

   229     } else if ([object isKindOfClass: [NSString class]]) {

   230         [self _encodeString: object];

   231     } else if ([object isKindOfClass: [NSDate class]]) {

   232         [self _encodeDate: object];

   233     } else if ([object isKindOfClass: [NSNull class]]) {

   234         [self _writeTag: 5 class: 0 constructed: NO bytes: NULL length: 0];

   235     } else if ([object isKindOfClass: [NSArray class]]) {

   236         [self _encodeCollection: object tag: 16 class: 0];

   237     } else if ([object isKindOfClass: [NSSet class]]) {

   238         [self _encodeCollection: object tag: 17 class: 0];

   239     } else if ([object isKindOfClass: [MYOID class]]) {

   240         [self _writeTag: 6 class: 0 constructed: NO data: [object DEREncoding]];

   241     } else if ([object isKindOfClass: [MYASN1Object class]]) {

   242         MYASN1Object *asn = object;

   243         if (asn.components)

   244             [self _encodeCollection: asn.components tag: asn.tag class: asn.tagClass];

   245         else

   246             [self _writeTag: asn.tag

   247                       class: asn.tagClass

   248                 constructed: asn.constructed

   249                        data: asn.value];

   250     } else {

   251         [NSException raise: MYDEREncoderException format: @"Can't DER-encode a %@", [object class]];

   252     }

   253 }

   256 - (NSData*) output {

   257     if (!_output && !_error) {

   258         @try{

   259             [self _encode: _rootObject];

   260         }@catch (NSException *x) {

   261             if ($equal(x.name, MYDEREncoderException)) {

   262                 self.error = MYError(2,MYASN1ErrorDomain, @"%@", x.reason);

   263                 return nil;

   264             } else

   265                 @throw(x);

   266         }

   267     }

   268     return _output;

   269 }

   271 @synthesize error=_error;

   274 @end

   278 #define $data(BYTES...)    ({const uint8_t bytes[] = {BYTES}; [NSData dataWithBytes: bytes length: sizeof(bytes)];})

   280 TestCase(DEREncoder) {

   281     CAssertEqual([MYDEREncoder encodeRootObject: [NSNull null] error: nil],

   282                  $data(0x05, 0x00));

   283     CAssertEqual([MYDEREncoder encodeRootObject: $true error: nil],

   284                  $data(0x01, 0x01, 0xFF));

   285     CAssertEqual([MYDEREncoder encodeRootObject: $false error: nil],

   286                  $data(0x01, 0x01, 0x00));

   288     // Integers:

   289     CAssertEqual([MYDEREncoder encodeRootObject: $object(0) error: nil],

   290                  $data(0x02, 0x01, 0x00));

   291     CAssertEqual([MYDEREncoder encodeRootObject: $object(1) error: nil],

   292                  $data(0x02, 0x01, 0x01));

   293     CAssertEqual([MYDEREncoder encodeRootObject: $object(-1) error: nil],

   294                  $data(0x02, 0x01, 0xFF));

   295     CAssertEqual([MYDEREncoder encodeRootObject: $object(72) error: nil],

   296                   $data(0x02, 0x01, 0x48));

   297     CAssertEqual([MYDEREncoder encodeRootObject: $object(-128) error: nil],

   298                  $data(0x02, 0x01, 0x80));

   299     CAssertEqual([MYDEREncoder encodeRootObject: $object(128) error: nil],

   300                  $data(0x02, 0x02, 0x00, 0x80));

   301     CAssertEqual([MYDEREncoder encodeRootObject: $object(255) error: nil],

   302                  $data(0x02, 0x02, 0x00, 0xFF));

   303     CAssertEqual([MYDEREncoder encodeRootObject: $object(-256) error: nil],

   304                  $data(0x02, 0x02, 0xFF, 0x00));

   305     CAssertEqual([MYDEREncoder encodeRootObject: $object(12345) error: nil],

   306                  $data(0x02, 0x02, 0x30,0x39));

   307     CAssertEqual([MYDEREncoder encodeRootObject: $object(-12345) error: nil],

   308                  $data(0x02, 0x02, 0xCF, 0xC7));

   309     CAssertEqual([MYDEREncoder encodeRootObject: $object(123456789) error: nil],

   310                  $data(0x02, 0x04, 0x07, 0x5B, 0xCD, 0x15));

   311     CAssertEqual([MYDEREncoder encodeRootObject: $object(-123456789) error: nil],

   312                  $data(0x02, 0x04, 0xF8, 0xA4, 0x32, 0xEB));

   313     CAssertEqual([MYDEREncoder encodeRootObject: $object(-123456789) error: nil],

   314                  $data(0x02, 0x04, 0xF8, 0xA4, 0x32, 0xEB));

   316     // Strings:

   317     CAssertEqual([MYDEREncoder encodeRootObject: @"hello" error: nil],

   318                  $data(0x13, 0x05, 'h', 'e', 'l', 'l', 'o'));

   319     CAssertEqual([MYDEREncoder encodeRootObject: @"thérè" error: nil],

   320                  $data(0x0C, 0x07, 't', 'h', 0xC3, 0xA9, 'r', 0xC3, 0xA8));

   322     // Dates:

   323     CAssertEqual([MYDEREncoder encodeRootObject: [NSDate dateWithTimeIntervalSinceReferenceDate: 265336576]

   324                                           error: nil],

   325                  $data(0x18, 0x0F, '2', '0', '0', '9', '0', '5', '3', '0', '0', '0', '3', '6', '1', '6', 'Z'));

   327     // Sequences:

   328     CAssertEqual([MYDEREncoder encodeRootObject: $array($object(72), $true) error: nil],

   329                  $data(0x30, 0x06,  0x02, 0x01, 0x48,  0x01, 0x01, 0xFF));

   330     CAssertEqual([MYDEREncoder encodeRootObject: $array( $array($object(72), $true),

   331                                                          $array($object(72), $true))

   332                                           error: nil],

   333                  $data(0x30, 0x10,

   334                        0x30, 0x06,  0x02, 0x01, 0x48,  0x01, 0x01, 0xFF,

   335                        0x30, 0x06,  0x02, 0x01, 0x48,  0x01, 0x01, 0xFF));

   336 }

   339 TestCase(EncodeCert) {

   340     NSError *error = nil;

   341     NSData *cert = [NSData dataWithContentsOfFile: @"../../Tests/iphonedev.cer"];  //TEMP

   342     id certObjects = MYBERParse(cert,&error);

   343     CAssertNil(error);

   344     Log(@"Decoded as:\n%@", [MYASN1Object dump: certObjects]);

   345     NSData *encoded = [MYDEREncoder encodeRootObject: certObjects error: &error];

   346     CAssertNil(error);

   347     id reDecoded = MYBERParse(encoded, &error);

   348     CAssertNil(error);

   349     Log(@"Re-decoded as:\n%@", [MYASN1Object dump: reDecoded]);

   350     [encoded writeToFile: @"../../Tests/iphonedev_reencoded.cer" atomically: YES];

   351     CAssertEqual(encoded,cert);

   352 }

author	Jens Alfke <jens@mooseyard.com>
	Wed Jun 03 17:20:53 2009 -0700 (2009-06-03)
changeset 17	90a70925562b
parent 16	c409dbc4f068
child 18	a06e44b9b898
permissions	-rw-r--r--