internal static Oid?GetSharedOrNullOid(ref AsnValueReader asnValueReader, Asn1Tag?expectedTag = null)
{
#if NET
Asn1Tag tag = asnValueReader.PeekTag();
// This isn't a valid OID, so return null and let whatever's going to happen happen.
if (tag.IsConstructed)
{
return(null);
}
Asn1Tag expected = expectedTag.GetValueOrDefault(Asn1Tag.ObjectIdentifier);
Debug.Assert(
expected.TagClass != TagClass.Universal ||
expected.TagValue == (int)UniversalTagNumber.ObjectIdentifier,
$"{nameof(GetSharedOrNullOid)} was called with the wrong Universal class tag: {expectedTag}");
// Not the tag we're expecting, so don't match.
if (!tag.HasSameClassAndValue(expected))
{
return(null);
}
ReadOnlySpan <byte> contentBytes = asnValueReader.PeekContentBytes();
Oid?ret = contentBytes switch
{
internal static void ValidateDer(ReadOnlySpan <byte> encodedValue)
{
try
{
Asn1Tag tag;
AsnValueReader reader = new AsnValueReader(encodedValue, AsnEncodingRules.DER);
while (reader.HasData)
{
tag = reader.PeekTag();
// If the tag is in the UNIVERSAL class
//
// DER limits the constructed encoding to SEQUENCE and SET, as well as anything which gets
// a defined encoding as being an IMPLICIT SEQUENCE.
if (tag.TagClass == TagClass.Universal)
{
switch ((UniversalTagNumber)tag.TagValue)
{
case UniversalTagNumber.External:
case UniversalTagNumber.Embedded:
case UniversalTagNumber.Sequence:
case UniversalTagNumber.Set:
case UniversalTagNumber.UnrestrictedCharacterString:
if (!tag.IsConstructed)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding);
}
break;
default:
if (tag.IsConstructed)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding);
}
break;
}
}
if (tag.IsConstructed)
{
ValidateDer(reader.PeekContentBytes());
}
// Skip past the current value.
reader.ReadEncodedValue();
}
}
catch (AsnContentException e)
{
throw new CryptographicException(SR.Cryptography_Der_Invalid_Encoding, e);
}
}
public static void PeekContentBytes_InvalidLength()
{
byte[] badLength = "04040203".HexToByteArray();
AsnReader reader = new AsnReader(badLength, AsnEncodingRules.BER);
Assert.Throws <CryptographicException>(() => reader.PeekContentBytes());
Assert.Throws <CryptographicException>(
() =>
{
AsnValueReader valueReader = new AsnValueReader(badLength, AsnEncodingRules.BER);
valueReader.PeekContentBytes();
});
}
