public static void TagMustBeCorrect_Custom(AsnEncodingRules ruleSet)
{
byte[] inputData = { 0x87, 2, 0, 0x80 };
byte[] output = new byte[inputData.Length];
AsnReader reader = new AsnReader(inputData, ruleSet);
Asn1Tag wrongTag1 = new Asn1Tag(TagClass.Application, 0);
Asn1Tag wrongTag2 = new Asn1Tag(TagClass.ContextSpecific, 1);
Asn1Tag correctTag = new Asn1Tag(TagClass.ContextSpecific, 7);
AssertExtensions.Throws <ArgumentException>(
"expectedTag",
() => reader.TryReadPrimitiveOctetString(out _, Asn1Tag.Null));
AssertExtensions.Throws <ArgumentException>(
"expectedTag",
() => reader.TryReadOctetString(output, out _, Asn1Tag.Null));
AssertExtensions.Throws <ArgumentException>(
"expectedTag",
() => reader.ReadOctetString(Asn1Tag.Null));
Assert.True(reader.HasData, "HasData after bad universal tag");
Assert.Throws <AsnContentException>(() => reader.TryReadPrimitiveOctetString(out _));
Assert.Throws <AsnContentException>(() => reader.TryReadOctetString(output, out _));
Assert.Throws <AsnContentException>(() => reader.ReadOctetString());
Assert.True(reader.HasData, "HasData after default tag");
Assert.Throws <AsnContentException>(() => reader.TryReadPrimitiveOctetString(out _, wrongTag1));
Assert.Throws <AsnContentException>(() => reader.TryReadOctetString(output, out _, wrongTag1));
Assert.Throws <AsnContentException>(() => reader.ReadOctetString(wrongTag1));
Assert.True(reader.HasData, "HasData after wrong custom class");
Assert.Throws <AsnContentException>(() => reader.TryReadPrimitiveOctetString(out _, wrongTag2));
Assert.Throws <AsnContentException>(() => reader.TryReadOctetString(output, out _, wrongTag2));
Assert.Throws <AsnContentException>(() => reader.ReadOctetString(wrongTag2));
Assert.True(reader.HasData, "HasData after wrong custom tag value");
Assert.True(reader.TryReadPrimitiveOctetString(out ReadOnlyMemory <byte> value, correctTag));
Assert.Equal("0080", value.ByteArrayToHex());
Assert.False(reader.HasData, "HasData after reading value");
reader = new AsnReader(inputData, ruleSet);
Assert.True(reader.TryReadOctetString(output.AsSpan(1), out int written, correctTag));
Assert.Equal("0080", output.AsSpan(1, written).ByteArrayToHex());
Assert.False(reader.HasData, "HasData after reading value");
reader = new AsnReader(inputData, ruleSet);
byte[] output2 = reader.ReadOctetString(correctTag);
Assert.Equal("0080", output2.ByteArrayToHex());
Assert.False(reader.HasData, "HasData after reading value");
}
public static void TryCopyOctetStringBytes_ExtremelyNested()
{
byte[] dataBytes = new byte[4 * 16384];
// This will build 2^14 nested indefinite length values.
// In the end, none of them contain any content.
//
// For what it's worth, the initial algorithm succeeded at 1061, and StackOverflowed with 1062.
int end = dataBytes.Length / 2;
// UNIVERSAL OCTET STRING [Constructed]
const byte Tag = 0x20 | (byte)UniversalTagNumber.OctetString;
for (int i = 0; i < end; i += 2)
{
dataBytes[i] = Tag;
// Indefinite length
dataBytes[i + 1] = 0x80;
}
AsnReader reader = new AsnReader(dataBytes, AsnEncodingRules.BER);
int bytesWritten;
Assert.True(reader.TryReadOctetString(Span <byte> .Empty, out bytesWritten));
Assert.Equal(0, bytesWritten);
reader = new AsnReader(dataBytes, AsnEncodingRules.BER);
byte[] output2 = reader.ReadOctetString();
// It's Same (ReferenceEqual) on .NET Core, but just Equal on .NET Framework
Assert.Equal(Array.Empty <byte>(), output2);
}
internal static ReadOnlyMemory <byte> GetContent(
ReadOnlyMemory <byte> wrappedContent,
string contentType)
{
// Read the input.
//
// PKCS7's id-data is written in both PKCS#7 and CMS as an OCTET STRING wrapping
// the arbitrary bytes, so the OCTET STRING must always be present.
//
// For other types, CMS says to always write an OCTET STRING, and to put the properly
// encoded data within it.
// PKCS#7 originally ommitted the OCTET STRING wrapper for this model, so this is the
// dynamic adapter.
//
// See https://tools.ietf.org/html/rfc5652#section-5.2.1
byte[]? rented = null;
int bytesWritten = 0;
try
{
AsnReader reader = new AsnReader(wrappedContent, AsnEncodingRules.BER);
if (reader.TryReadPrimitiveOctetString(out ReadOnlyMemory <byte> inner))
{
return(inner);
}
rented = CryptoPool.Rent(wrappedContent.Length);
if (!reader.TryReadOctetString(rented, out bytesWritten))
{
Debug.Fail($"TryCopyOctetStringBytes failed with an array larger than the encoded value");
throw new CryptographicException();
}
return(rented.AsSpan(0, bytesWritten).ToArray());
}
catch (Exception) when(contentType != Oids.Pkcs7Data)
{
}
catch (AsnContentException e)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding, e);
}
finally
{
if (rented != null)
{
CryptoPool.Return(rented, bytesWritten);
}
}
// PKCS#7 encoding for something other than id-data.
Debug.Assert(contentType != Oids.Pkcs7Data);
return(wrappedContent);
}
public static void TryReadOctetStringBytes_Fails(AsnEncodingRules ruleSet, string inputHex)
{
byte[] inputData = inputHex.HexToByteArray();
AsnReader reader = new AsnReader(inputData, ruleSet);
bool didRead = reader.TryReadOctetString(
Span <byte> .Empty,
out int bytesWritten);
Assert.False(didRead, "reader.TryReadOctetString");
Assert.Equal(0, bytesWritten);
}
private static void TryReadOctetStringBytes_Throws_Helper(
AsnEncodingRules ruleSet,
byte[] input)
{
AsnReader reader = new AsnReader(input, ruleSet);
Assert.Throws <AsnContentException>(
() =>
{
reader.TryReadOctetString(
Span <byte> .Empty,
out int bytesWritten);
});
}
public static void TryReadOctetStringBytes_Success(
AsnEncodingRules ruleSet,
string inputHex,
string expectedHex)
{
byte[] inputData = inputHex.HexToByteArray();
byte[] output = new byte[expectedHex.Length / 2];
AsnReader reader = new AsnReader(inputData, ruleSet);
bool didRead = reader.TryReadOctetString(
output,
out int bytesWritten);
Assert.True(didRead, "reader.TryReadOctetString");
Assert.Equal(expectedHex, output.AsSpan(0, bytesWritten).ByteArrayToHex());
reader = new AsnReader(inputData, ruleSet);
byte[] output2 = reader.ReadOctetString();
Assert.Equal(output, output2);
}
public static void TryCopyOctetStringBytes_Success_CER_MaxPrimitiveLength()
{
// CER says that the maximum encoding length for an OctetString primitive
// is 1000.
//
// So we need 04 [1000] { 1000 anythings }
// 1000 => 0x3E8, so the length encoding is 82 03 E8.
// 1000 + 3 + 1 == 1004
byte[] input = new byte[1004];
input[0] = 0x04;
input[1] = 0x82;
input[2] = 0x03;
input[3] = 0xE8;
// Content
input[4] = 0x02;
input[5] = 0xA0;
input[1002] = 0xA5;
input[1003] = 0xFC;
byte[] output = new byte[1000];
AsnReader reader = new AsnReader(input, AsnEncodingRules.CER);
bool success = reader.TryReadOctetString(
output,
out int bytesWritten);
Assert.True(success, "reader.TryReadOctetString");
Assert.Equal(1000, bytesWritten);
Assert.Equal(
input.AsSpan(4).ByteArrayToHex(),
output.ByteArrayToHex());
reader = new AsnReader(input, AsnEncodingRules.CER);
byte[] output2 = reader.ReadOctetString();
Assert.Equal(output, output2);
}
public static void TryReadPrimitiveOctetStringBytes_Throws_CER_TooLong()
{
// CER says that the maximum encoding length for an OctetString primitive
// is 1000.
//
// So we need 04 [1001] { 1001 0x00s }
// 1001 => 0x3E9, so the length encoding is 82 03 E9.
// 1001 + 3 + 1 == 1005
byte[] input = new byte[1005];
input[0] = 0x04;
input[1] = 0x82;
input[2] = 0x03;
input[3] = 0xE9;
AsnReader reader = new AsnReader(input, AsnEncodingRules.CER);
Assert.Throws <AsnContentException>(
() => reader.TryReadPrimitiveOctetString(out ReadOnlyMemory <byte> contents));
Assert.Throws <AsnContentException>(
() => reader.TryReadOctetString(new byte[input.Length], out _));
Assert.Throws <AsnContentException>(() => reader.ReadOctetString());
}
internal static AlgorithmIdentifier ToPresentationObject(this AlgorithmIdentifierAsn asn)
{
int keyLength;
byte[] parameters = Array.Empty <byte>();
switch (asn.Algorithm)
{
case Oids.Rc2Cbc:
{
if (asn.Parameters == null)
{
keyLength = 0;
break;
}
Rc2CbcParameters rc2Params = Rc2CbcParameters.Decode(
asn.Parameters.Value,
AsnEncodingRules.BER);
int keySize = rc2Params.GetEffectiveKeyBits();
// These are the only values .NET Framework would set.
switch (keySize)
{
case 40:
case 56:
case 64:
case 128:
keyLength = keySize;
break;
default:
keyLength = 0;
break;
}
break;
}
case Oids.Rc4:
{
if (asn.Parameters == null)
{
keyLength = 0;
break;
}
int saltLen = 0;
try
{
AsnReader reader = new AsnReader(asn.Parameters.Value, AsnEncodingRules.BER);
// DER NULL is considered the same as not present.
// No call to ReadNull() is necessary because the serializer already verified that
// there's no data after the [AnyValue] value.
if (reader.PeekTag() != Asn1Tag.Null)
{
if (reader.TryReadPrimitiveOctetString(out ReadOnlyMemory <byte> contents))
{
saltLen = contents.Length;
}
else
{
Span <byte> salt = stackalloc byte[KeyLengths.Rc4Max_128Bit / 8];
if (!reader.TryReadOctetString(salt, out saltLen))
{
throw new CryptographicException();
}
}
}
}
catch (AsnContentException e)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding, e);
}
keyLength = KeyLengths.Rc4Max_128Bit - 8 * saltLen;
break;
}
case Oids.DesCbc:
keyLength = KeyLengths.Des_64Bit;
break;
case Oids.TripleDesCbc:
keyLength = KeyLengths.TripleDes_192Bit;
break;
case Oids.RsaOaep when !asn.HasNullEquivalentParameters():
keyLength = 0;
Debug.Assert(asn.Parameters != null);
parameters = asn.Parameters.Value.ToArray();
break;
default:
// .NET Framework doesn't set a keylength for AES, or any other algorithm than the ones
// listed here.
keyLength = 0;
break;
}
return(new AlgorithmIdentifier(new Oid(asn.Algorithm), keyLength)
{
Parameters = parameters
});
}
public static void TryCopyOctetStringBytes_Success_CER_MinConstructedLength()
{
// CER says that the maximum encoding length for an OctetString primitive
// is 1000, and that a constructed form must be used for values greater
// than 1000 bytes, with segments dividing up for each thousand
// [1000, 1000, ..., len%1000].
//
// So our smallest constructed form is 1001 bytes, [1000, 1]
//
// 24 80 (indefinite constructed octet string)
// 04 82 03 E9 (primitive octet string, 1000 bytes)
// [1000 content bytes]
// 04 01 (primitive octet string, 1 byte)
// pp
// 00 00 (end of contents, 0 bytes)
// 1011 total.
byte[] input = new byte[1011];
int offset = 0;
// CONSTRUCTED OCTET STRING (Indefinite)
input[offset++] = 0x24;
input[offset++] = 0x80;
// OCTET STRING (1000)
input[offset++] = 0x04;
input[offset++] = 0x82;
input[offset++] = 0x03;
input[offset++] = 0xE8;
// Primitive 1: (55 A0 :: A5 FC) (1000)
input[offset++] = 0x55;
input[offset] = 0xA0;
offset += 997;
input[offset++] = 0xA5;
input[offset++] = 0xFC;
// OCTET STRING (1)
input[offset++] = 0x04;
input[offset++] = 0x01;
// Primitive 2: One more byte
input[offset] = 0xF7;
byte[] expected = new byte[1001];
offset = 0;
expected[offset++] = 0x55;
expected[offset] = 0xA0;
offset += 997;
expected[offset++] = 0xA5;
expected[offset++] = 0xFC;
expected[offset] = 0xF7;
byte[] output = new byte[1001];
AsnReader reader = new AsnReader(input, AsnEncodingRules.CER);
bool success = reader.TryReadOctetString(
output,
out int bytesWritten);
Assert.True(success, "reader.TryReadOctetString");
Assert.Equal(1001, bytesWritten);
Assert.Equal(
expected.ByteArrayToHex(),
output.ByteArrayToHex());
reader = new AsnReader(input, AsnEncodingRules.CER);
byte[] output2 = reader.ReadOctetString();
Assert.Equal(output, output2);
}