diff -r 000000000000 -r c409dbc4f068 MYBERParser.m --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/MYBERParser.m Tue Jun 02 13:16:28 2009 -0700 @@ -0,0 +1,298 @@ +// +// MYBERParser.m +// MYCrypto +// +// Created by Jens Alfke on 6/2/09. +// Copyright 2009 Jens Alfke. All rights reserved. +// + +#import "MYBERParser.h" +#import "MYASN1Object.h" +#import "MYOID.h" +#import "MYErrorUtils.h" +#import "CollectionUtils.h" +#import "Test.h" + + +#define MYBERParserException @"MYBERParserException" + + + +typedef struct { + const uint8_t *nextChar; + size_t length; +} InputData; + + +static void requireLength (size_t length, size_t expectedLength) { + if (length != expectedLength) + [NSException raise: MYBERParserException format: @"Unexpected value length"]; +} + + +static const void* readOrDie (InputData *input, size_t len) { + if (len > input->length) + [NSException raise: MYBERParserException format: @"Unexpected EOF on input"]; + const void *bytes = input->nextChar; + input->nextChar += len; + input->length -= len; + return bytes; +} + + +static NSData* readDataOrDie(InputData *input, size_t length) { + return [NSMutableData dataWithBytes: readOrDie(input,length) length: length]; +} + + +static NSString* readStringOrDie(InputData *input, size_t length, NSStringEncoding encoding) { + NSString *str = [[NSString alloc] initWithBytes: readOrDie(input,length) + length: length + encoding: encoding]; + if (!str) + [NSException raise: MYBERParserException format: @"Unparseable string"]; + return [str autorelease]; +} + + +static uint32_t readBigEndianUnsignedInteger (InputData *input, size_t length) { + if (length == 0 || length > 4) + [NSException raise: MYBERParserException format: @"Invalid integer length"]; + uint32_t result = 0; + memcpy(((uint8_t*)&result)+(4-length), readOrDie(input, length), length); + return result; +} + +static int32_t readBigEndianSignedInteger (InputData *input, size_t length) { + int32_t result = (int32_t) readBigEndianUnsignedInteger(input,length); + uint8_t *dst = ((uint8_t*)&result)+(4-length); + if (*dst & 0x80) { // sign-extend negative value + while (--dst >= (uint8_t*)&result) + *dst = 0xFF; + } + return result; +} + + +NSDateFormatter* MYBERGeneralizedTimeFormatter() { + static NSDateFormatter *sFmt; + if (!sFmt) { + sFmt = [[NSDateFormatter alloc] init]; + sFmt.dateFormat = @"yyyyMMddHHmmss'Z'"; + sFmt.timeZone = [NSTimeZone timeZoneWithName: @"GMT"]; + } + return sFmt; +} + +NSDateFormatter* MYBERUTCTimeFormatter() { + static NSDateFormatter *sFmt; + if (!sFmt) { + sFmt = [[NSDateFormatter alloc] init]; + sFmt.dateFormat = @"yyMMddHHmmss'Z'"; + sFmt.timeZone = [NSTimeZone timeZoneWithName: @"GMT"]; + } + return sFmt; +} + +static NSDate* parseDate (NSString *dateStr, unsigned tag) { + NSDateFormatter *fmt = (tag==23 ?MYBERUTCTimeFormatter() :MYBERGeneralizedTimeFormatter()); + NSDate *date = [fmt dateFromString: dateStr]; + if (!date) + [NSException raise: MYBERParserException format: @"Unparseable date '%@'", dateStr]; + return date; +} + + +static id parseBER(InputData *input) { + struct { + unsigned tag :5; + unsigned isConstructed :1; + unsigned tagClass :2; + unsigned length :7; + unsigned isLengthLong :1; + } header; + memcpy(&header, readOrDie(input,2), 2); + + if (header.tag == 0x1F) + [NSException raise: MYBERParserException format: @"Long tags not supported"]; + + // Parse the length: + size_t length; + if (!header.isLengthLong) + length = header.length; + else if (header.length == 0) + [NSException raise: MYBERParserException format: @"Indefinite length not supported"]; + else + length = NSSwapBigIntToHost(readBigEndianUnsignedInteger(input,header.length)); + + Class defaultClass = [MYASN1Object class]; + + // Tag values can be found in . I'm not using them here because that + // header does not exist on iPhone! + + if (header.isConstructed) { + // Constructed: + NSMutableArray *items = $marray(); + InputData subInput = {input->nextChar, length}; + while (subInput.length > 0) { + [items addObject: parseBER(&subInput)]; + } + input->nextChar += length; + input->length -= length; + + switch (header.tag) { + case 16: // sequence + return items; + case 17: // set + return [NSSet setWithArray: items]; + default: + return [[[MYASN1Object alloc] initWithTag: header.tag + ofClass: header.tagClass + components: items] autorelease]; + } + } else { + // Primitive: + switch (header.tag) { + case 1: { // boolean + requireLength(length,1); + return *(const uint8_t*)readOrDie(input, 1) ?$true :$false; + } + case 2: // integer + case 10: // enum + { + if (length <= 4) { + int32_t value = NSSwapBigIntToHost(readBigEndianSignedInteger(input,length)); + return [NSNumber numberWithInteger: value]; + } else { + // Big integer! + defaultClass = [MYASN1BigInteger class]; + break; + } + } + case 3: // bitstring + { + UInt8 unusedBits = *(const UInt8*) readOrDie(input, 1); + if (unusedBits) + Log(@"Bit-string has %u unused bits", (unsigned)unusedBits); + if (unusedBits > 7 || length < 1) + [NSException raise: MYBERParserException format: @"Bogus bit-string"]; + return [[[MYBitString alloc] initWithBits: readDataOrDie(input, length-1) + count: 8*(length-1) - unusedBits] autorelease]; + } + case 4: // octetstring + return readDataOrDie(input, length); + case 5: // null + requireLength(length,0); + return [NSNull null]; + case 6: // OID + return [[[MYOID alloc] initWithBEREncoding: readDataOrDie(input, length)] autorelease]; + case 12: // UTF8String + return readStringOrDie(input,length,NSUTF8StringEncoding); + case 18: // numeric string + case 19: // printable string: + return readStringOrDie(input,length,NSASCIIStringEncoding); + case 23: // UTC time: + case 24: // Generalized time: + return parseDate(readStringOrDie(input,length,NSASCIIStringEncoding), header.tag); + default: + break; + } + } + + // Generic case -- create and return a MYASN1Object: + NSData *value = readDataOrDie(input, length); + id result = [[[defaultClass alloc] initWithTag: header.tag + ofClass: header.tagClass + constructed: header.isConstructed + value: value] autorelease]; + if( defaultClass == [MYASN1Object class]) + Warn(@"parseBER: Returning default %@", result); + return result; +} + + +id MYBERParse (NSData *ber, NSError **outError) { + @try{ + InputData input = {ber.bytes, ber.length}; + return parseBER(&input); + }@catch (NSException *x) { + if ($equal(x.name, MYBERParserException)) { + *outError = MYError(1,MYASN1ErrorDomain, @"%@", x.reason); + } else { + @throw(x); + } + } + return nil; +} + + + + +#pragma mark - +#pragma mark TEST CASES: + + +#define $data(BYTES...) ({const uint8_t bytes[] = {BYTES}; [NSData dataWithBytes: bytes length: sizeof(bytes)];}) + +TestCase(ParseBER) { + CAssertEqual(MYBERParse($data(0x05, 0x00), nil), + [NSNull null]); + CAssertEqual(MYBERParse($data(0x01, 0x01, 0xFF), nil), + $true); + CAssertEqual(MYBERParse($data(0x01, 0x01, 0x00), nil), + $false); + + // integers: + CAssertEqual(MYBERParse($data(0x02, 0x01, 0x00), nil), + $object(0)); + CAssertEqual(MYBERParse($data(0x02, 0x01, 0x48), nil), + $object(72)); + CAssertEqual(MYBERParse($data(0x02, 0x01, 0x80), nil), + $object(-128)); + CAssertEqual(MYBERParse($data(0x02, 0x02, 0x00, 0x80), nil), + $object(128)); + CAssertEqual(MYBERParse($data(0x02, 0x02, 0x30,0x39), nil), + $object(12345)); + CAssertEqual(MYBERParse($data(0x02, 0x02, 0xCF, 0xC7), nil), + $object(-12345)); + CAssertEqual(MYBERParse($data(0x02, 0x04, 0x07, 0x5B, 0xCD, 0x15), nil), + $object(123456789)); + CAssertEqual(MYBERParse($data(0x02, 0x04, 0xF8, 0xA4, 0x32, 0xEB), nil), + $object(-123456789)); + CAssertEqual(MYBERParse($data(0x02, 0x04, 0xF8, 0xA4, 0x32, 0xEB), nil), + $object(-123456789)); + + // octet strings: + CAssertEqual(MYBERParse($data(0x04, 0x05, 'h', 'e', 'l', 'l', 'o'), nil), + [@"hello" dataUsingEncoding: NSASCIIStringEncoding]); + CAssertEqual(MYBERParse($data(0x04, 0x00), nil), + [NSData data]); + CAssertEqual(MYBERParse($data(0x0C, 0x05, 'h', 'e', 'l', 'l', 'o'), nil), + @"hello"); + + // sequences: + CAssertEqual(MYBERParse($data(0x30, 0x06, 0x02, 0x01, 0x48, 0x01, 0x01, 0xFF), nil), + $array($object(72), $true)); + CAssertEqual(MYBERParse($data(0x30, 0x10, + 0x30, 0x06, 0x02, 0x01, 0x48, 0x01, 0x01, 0xFF, + 0x30, 0x06, 0x02, 0x01, 0x48, 0x01, 0x01, 0xFF), nil), + $array( $array($object(72), $true), $array($object(72), $true))); +} + + +TestCase(ParseCert) { + NSData *cert = [NSData dataWithContentsOfFile: @"../../Tests/selfsigned.cer"]; + NSError *error = nil; + id parsed = MYBERParse(cert,&error); + CAssert(parsed); + CAssertNil(error); + NSString *dump = [MYASN1Object dump: parsed]; + CAssert(dump); + + cert = [NSData dataWithContentsOfFile: @"../../Tests/iphonedev.cer"]; + parsed = MYBERParse(cert,&error); + CAssert(parsed); + CAssertNil(error); + dump = [MYASN1Object dump: parsed]; + CAssert(dump); +}