1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/MYBERParser.m Tue Jun 02 13:16:28 2009 -0700
1.3 @@ -0,0 +1,298 @@
1.4 +//
1.5 +// MYBERParser.m
1.6 +// MYCrypto
1.7 +//
1.8 +// Created by Jens Alfke on 6/2/09.
1.9 +// Copyright 2009 Jens Alfke. All rights reserved.
1.10 +//
1.11 +
1.12 +#import "MYBERParser.h"
1.13 +#import "MYASN1Object.h"
1.14 +#import "MYOID.h"
1.15 +#import "MYErrorUtils.h"
1.16 +#import "CollectionUtils.h"
1.17 +#import "Test.h"
1.18 +
1.19 +
1.20 +#define MYBERParserException @"MYBERParserException"
1.21 +
1.22 +
1.23 +
1.24 +typedef struct {
1.25 + const uint8_t *nextChar;
1.26 + size_t length;
1.27 +} InputData;
1.28 +
1.29 +
1.30 +static void requireLength (size_t length, size_t expectedLength) {
1.31 + if (length != expectedLength)
1.32 + [NSException raise: MYBERParserException format: @"Unexpected value length"];
1.33 +}
1.34 +
1.35 +
1.36 +static const void* readOrDie (InputData *input, size_t len) {
1.37 + if (len > input->length)
1.38 + [NSException raise: MYBERParserException format: @"Unexpected EOF on input"];
1.39 + const void *bytes = input->nextChar;
1.40 + input->nextChar += len;
1.41 + input->length -= len;
1.42 + return bytes;
1.43 +}
1.44 +
1.45 +
1.46 +static NSData* readDataOrDie(InputData *input, size_t length) {
1.47 + return [NSMutableData dataWithBytes: readOrDie(input,length) length: length];
1.48 +}
1.49 +
1.50 +
1.51 +static NSString* readStringOrDie(InputData *input, size_t length, NSStringEncoding encoding) {
1.52 + NSString *str = [[NSString alloc] initWithBytes: readOrDie(input,length)
1.53 + length: length
1.54 + encoding: encoding];
1.55 + if (!str)
1.56 + [NSException raise: MYBERParserException format: @"Unparseable string"];
1.57 + return [str autorelease];
1.58 +}
1.59 +
1.60 +
1.61 +static uint32_t readBigEndianUnsignedInteger (InputData *input, size_t length) {
1.62 + if (length == 0 || length > 4)
1.63 + [NSException raise: MYBERParserException format: @"Invalid integer length"];
1.64 + uint32_t result = 0;
1.65 + memcpy(((uint8_t*)&result)+(4-length), readOrDie(input, length), length);
1.66 + return result;
1.67 +}
1.68 +
1.69 +static int32_t readBigEndianSignedInteger (InputData *input, size_t length) {
1.70 + int32_t result = (int32_t) readBigEndianUnsignedInteger(input,length);
1.71 + uint8_t *dst = ((uint8_t*)&result)+(4-length);
1.72 + if (*dst & 0x80) { // sign-extend negative value
1.73 + while (--dst >= (uint8_t*)&result)
1.74 + *dst = 0xFF;
1.75 + }
1.76 + return result;
1.77 +}
1.78 +
1.79 +
1.80 +NSDateFormatter* MYBERGeneralizedTimeFormatter() {
1.81 + static NSDateFormatter *sFmt;
1.82 + if (!sFmt) {
1.83 + sFmt = [[NSDateFormatter alloc] init];
1.84 + sFmt.dateFormat = @"yyyyMMddHHmmss'Z'";
1.85 + sFmt.timeZone = [NSTimeZone timeZoneWithName: @"GMT"];
1.86 + }
1.87 + return sFmt;
1.88 +}
1.89 +
1.90 +NSDateFormatter* MYBERUTCTimeFormatter() {
1.91 + static NSDateFormatter *sFmt;
1.92 + if (!sFmt) {
1.93 + sFmt = [[NSDateFormatter alloc] init];
1.94 + sFmt.dateFormat = @"yyMMddHHmmss'Z'";
1.95 + sFmt.timeZone = [NSTimeZone timeZoneWithName: @"GMT"];
1.96 + }
1.97 + return sFmt;
1.98 +}
1.99 +
1.100 +static NSDate* parseDate (NSString *dateStr, unsigned tag) {
1.101 + NSDateFormatter *fmt = (tag==23 ?MYBERUTCTimeFormatter() :MYBERGeneralizedTimeFormatter());
1.102 + NSDate *date = [fmt dateFromString: dateStr];
1.103 + if (!date)
1.104 + [NSException raise: MYBERParserException format: @"Unparseable date '%@'", dateStr];
1.105 + return date;
1.106 +}
1.107 +
1.108 +
1.109 +static id parseBER(InputData *input) {
1.110 + struct {
1.111 + unsigned tag :5;
1.112 + unsigned isConstructed :1;
1.113 + unsigned tagClass :2;
1.114 + unsigned length :7;
1.115 + unsigned isLengthLong :1;
1.116 + } header;
1.117 + memcpy(&header, readOrDie(input,2), 2);
1.118 +
1.119 + if (header.tag == 0x1F)
1.120 + [NSException raise: MYBERParserException format: @"Long tags not supported"];
1.121 +
1.122 + // Parse the length:
1.123 + size_t length;
1.124 + if (!header.isLengthLong)
1.125 + length = header.length;
1.126 + else if (header.length == 0)
1.127 + [NSException raise: MYBERParserException format: @"Indefinite length not supported"];
1.128 + else
1.129 + length = NSSwapBigIntToHost(readBigEndianUnsignedInteger(input,header.length));
1.130 +
1.131 + Class defaultClass = [MYASN1Object class];
1.132 +
1.133 + // Tag values can be found in <Security/x509defs.h>. I'm not using them here because that
1.134 + // header does not exist on iPhone!
1.135 +
1.136 + if (header.isConstructed) {
1.137 + // Constructed:
1.138 + NSMutableArray *items = $marray();
1.139 + InputData subInput = {input->nextChar, length};
1.140 + while (subInput.length > 0) {
1.141 + [items addObject: parseBER(&subInput)];
1.142 + }
1.143 + input->nextChar += length;
1.144 + input->length -= length;
1.145 +
1.146 + switch (header.tag) {
1.147 + case 16: // sequence
1.148 + return items;
1.149 + case 17: // set
1.150 + return [NSSet setWithArray: items];
1.151 + default:
1.152 + return [[[MYASN1Object alloc] initWithTag: header.tag
1.153 + ofClass: header.tagClass
1.154 + components: items] autorelease];
1.155 + }
1.156 + } else {
1.157 + // Primitive:
1.158 + switch (header.tag) {
1.159 + case 1: { // boolean
1.160 + requireLength(length,1);
1.161 + return *(const uint8_t*)readOrDie(input, 1) ?$true :$false;
1.162 + }
1.163 + case 2: // integer
1.164 + case 10: // enum
1.165 + {
1.166 + if (length <= 4) {
1.167 + int32_t value = NSSwapBigIntToHost(readBigEndianSignedInteger(input,length));
1.168 + return [NSNumber numberWithInteger: value];
1.169 + } else {
1.170 + // Big integer!
1.171 + defaultClass = [MYASN1BigInteger class];
1.172 + break;
1.173 + }
1.174 + }
1.175 + case 3: // bitstring
1.176 + {
1.177 + UInt8 unusedBits = *(const UInt8*) readOrDie(input, 1);
1.178 + if (unusedBits)
1.179 + Log(@"Bit-string has %u unused bits", (unsigned)unusedBits);
1.180 + if (unusedBits > 7 || length < 1)
1.181 + [NSException raise: MYBERParserException format: @"Bogus bit-string"];
1.182 + return [[[MYBitString alloc] initWithBits: readDataOrDie(input, length-1)
1.183 + count: 8*(length-1) - unusedBits] autorelease];
1.184 + }
1.185 + case 4: // octetstring
1.186 + return readDataOrDie(input, length);
1.187 + case 5: // null
1.188 + requireLength(length,0);
1.189 + return [NSNull null];
1.190 + case 6: // OID
1.191 + return [[[MYOID alloc] initWithBEREncoding: readDataOrDie(input, length)] autorelease];
1.192 + case 12: // UTF8String
1.193 + return readStringOrDie(input,length,NSUTF8StringEncoding);
1.194 + case 18: // numeric string
1.195 + case 19: // printable string:
1.196 + return readStringOrDie(input,length,NSASCIIStringEncoding);
1.197 + case 23: // UTC time:
1.198 + case 24: // Generalized time:
1.199 + return parseDate(readStringOrDie(input,length,NSASCIIStringEncoding), header.tag);
1.200 + default:
1.201 + break;
1.202 + }
1.203 + }
1.204 +
1.205 + // Generic case -- create and return a MYASN1Object:
1.206 + NSData *value = readDataOrDie(input, length);
1.207 + id result = [[[defaultClass alloc] initWithTag: header.tag
1.208 + ofClass: header.tagClass
1.209 + constructed: header.isConstructed
1.210 + value: value] autorelease];
1.211 + if( defaultClass == [MYASN1Object class])
1.212 + Warn(@"parseBER: Returning default %@", result);
1.213 + return result;
1.214 +}
1.215 +
1.216 +
1.217 +id MYBERParse (NSData *ber, NSError **outError) {
1.218 + @try{
1.219 + InputData input = {ber.bytes, ber.length};
1.220 + return parseBER(&input);
1.221 + }@catch (NSException *x) {
1.222 + if ($equal(x.name, MYBERParserException)) {
1.223 + *outError = MYError(1,MYASN1ErrorDomain, @"%@", x.reason);
1.224 + } else {
1.225 + @throw(x);
1.226 + }
1.227 + }
1.228 + return nil;
1.229 +}
1.230 +
1.231 +
1.232 +
1.233 +
1.234 +#pragma mark -
1.235 +#pragma mark TEST CASES:
1.236 +
1.237 +
1.238 +#define $data(BYTES...) ({const uint8_t bytes[] = {BYTES}; [NSData dataWithBytes: bytes length: sizeof(bytes)];})
1.239 +
1.240 +TestCase(ParseBER) {
1.241 + CAssertEqual(MYBERParse($data(0x05, 0x00), nil),
1.242 + [NSNull null]);
1.243 + CAssertEqual(MYBERParse($data(0x01, 0x01, 0xFF), nil),
1.244 + $true);
1.245 + CAssertEqual(MYBERParse($data(0x01, 0x01, 0x00), nil),
1.246 + $false);
1.247 +
1.248 + // integers:
1.249 + CAssertEqual(MYBERParse($data(0x02, 0x01, 0x00), nil),
1.250 + $object(0));
1.251 + CAssertEqual(MYBERParse($data(0x02, 0x01, 0x48), nil),
1.252 + $object(72));
1.253 + CAssertEqual(MYBERParse($data(0x02, 0x01, 0x80), nil),
1.254 + $object(-128));
1.255 + CAssertEqual(MYBERParse($data(0x02, 0x02, 0x00, 0x80), nil),
1.256 + $object(128));
1.257 + CAssertEqual(MYBERParse($data(0x02, 0x02, 0x30,0x39), nil),
1.258 + $object(12345));
1.259 + CAssertEqual(MYBERParse($data(0x02, 0x02, 0xCF, 0xC7), nil),
1.260 + $object(-12345));
1.261 + CAssertEqual(MYBERParse($data(0x02, 0x04, 0x07, 0x5B, 0xCD, 0x15), nil),
1.262 + $object(123456789));
1.263 + CAssertEqual(MYBERParse($data(0x02, 0x04, 0xF8, 0xA4, 0x32, 0xEB), nil),
1.264 + $object(-123456789));
1.265 + CAssertEqual(MYBERParse($data(0x02, 0x04, 0xF8, 0xA4, 0x32, 0xEB), nil),
1.266 + $object(-123456789));
1.267 +
1.268 + // octet strings:
1.269 + CAssertEqual(MYBERParse($data(0x04, 0x05, 'h', 'e', 'l', 'l', 'o'), nil),
1.270 + [@"hello" dataUsingEncoding: NSASCIIStringEncoding]);
1.271 + CAssertEqual(MYBERParse($data(0x04, 0x00), nil),
1.272 + [NSData data]);
1.273 + CAssertEqual(MYBERParse($data(0x0C, 0x05, 'h', 'e', 'l', 'l', 'o'), nil),
1.274 + @"hello");
1.275 +
1.276 + // sequences:
1.277 + CAssertEqual(MYBERParse($data(0x30, 0x06, 0x02, 0x01, 0x48, 0x01, 0x01, 0xFF), nil),
1.278 + $array($object(72), $true));
1.279 + CAssertEqual(MYBERParse($data(0x30, 0x10,
1.280 + 0x30, 0x06, 0x02, 0x01, 0x48, 0x01, 0x01, 0xFF,
1.281 + 0x30, 0x06, 0x02, 0x01, 0x48, 0x01, 0x01, 0xFF), nil),
1.282 + $array( $array($object(72), $true), $array($object(72), $true)));
1.283 +}
1.284 +
1.285 +
1.286 +TestCase(ParseCert) {
1.287 + NSData *cert = [NSData dataWithContentsOfFile: @"../../Tests/selfsigned.cer"];
1.288 + NSError *error = nil;
1.289 + id parsed = MYBERParse(cert,&error);
1.290 + CAssert(parsed);
1.291 + CAssertNil(error);
1.292 + NSString *dump = [MYASN1Object dump: parsed];
1.293 + CAssert(dump);
1.294 +
1.295 + cert = [NSData dataWithContentsOfFile: @"../../Tests/iphonedev.cer"];
1.296 + parsed = MYBERParse(cert,&error);
1.297 + CAssert(parsed);
1.298 + CAssertNil(error);
1.299 + dump = [MYASN1Object dump: parsed];
1.300 + CAssert(dump);
1.301 +}