TbsCertificateAsn.cs

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using System.Collections.Generic;
using System.Formats.Asn1;
using System.Security.Cryptography.Asn1;
 
namespace System.Security.Cryptography.X509Certificates.Asn1;
 
internal struct TbsCertificateAsn
{
    internal int Version;
 
    internal ReadOnlyMemory<byte> SerialNumber;
 
    internal System.Security.Cryptography.Asn1.AlgorithmIdentifierAsn SignatureAlgorithm;
 
    internal ReadOnlyMemory<byte> Issuer;
 
    internal ValidityAsn Validity;
 
    internal ReadOnlyMemory<byte> Subject;
 
    internal System.Security.Cryptography.Asn1.SubjectPublicKeyInfoAsn SubjectPublicKeyInfo;
 
    internal ReadOnlyMemory<byte>? IssuerUniqueId;
 
    internal ReadOnlyMemory<byte>? SubjectUniqueId;
 
    internal X509ExtensionAsn[] Extensions;
 
    private static ReadOnlySpan<byte> DefaultVersion => new byte[3] { 2, 1, 0 };
 
    internal void Encode(AsnWriter writer)
    {
        Encode(writer, Asn1Tag.Sequence);
    }
 
    internal void Encode(AsnWriter writer, Asn1Tag tag)
    {
        writer.PushSequence(tag);
        AsnWriter asnWriter = new AsnWriter(AsnEncodingRules.DER);
        asnWriter.WriteInteger(Version);
        if (!asnWriter.EncodedValueEquals(DefaultVersion))
        {
            writer.PushSequence(new Asn1Tag(TagClass.ContextSpecific, 0));
            asnWriter.CopyTo(writer);
            writer.PopSequence(new Asn1Tag(TagClass.ContextSpecific, 0));
        }
        writer.WriteInteger(SerialNumber.Span);
        SignatureAlgorithm.Encode(writer);
        if (!Asn1Tag.TryDecode(Issuer.Span, out var tag2, out var bytesConsumed) || !tag2.HasSameClassAndValue(new Asn1Tag(UniversalTagNumber.Sequence)))
        {
            throw new CryptographicException();
        }
        try
        {
            writer.WriteEncodedValue(Issuer.Span);
        }
        catch (ArgumentException inner)
        {
            throw new CryptographicException(System.SR.Cryptography_Der_Invalid_Encoding, inner);
        }
        Validity.Encode(writer);
        if (!Asn1Tag.TryDecode(Subject.Span, out var tag3, out bytesConsumed) || !tag3.HasSameClassAndValue(new Asn1Tag(UniversalTagNumber.Sequence)))
        {
            throw new CryptographicException();
        }
        try
        {
            writer.WriteEncodedValue(Subject.Span);
        }
        catch (ArgumentException inner2)
        {
            throw new CryptographicException(System.SR.Cryptography_Der_Invalid_Encoding, inner2);
        }
        SubjectPublicKeyInfo.Encode(writer);
        if (IssuerUniqueId.HasValue)
        {
            writer.WriteBitString(IssuerUniqueId.Value.Span, 0, new Asn1Tag(TagClass.ContextSpecific, 1));
        }
        if (SubjectUniqueId.HasValue)
        {
            writer.WriteBitString(SubjectUniqueId.Value.Span, 0, new Asn1Tag(TagClass.ContextSpecific, 2));
        }
        if (Extensions != null)
        {
            writer.PushSequence(new Asn1Tag(TagClass.ContextSpecific, 3));
            writer.PushSequence();
            for (int i = 0; i < Extensions.Length; i++)
            {
                Extensions[i].Encode(writer);
            }
            writer.PopSequence();
            writer.PopSequence(new Asn1Tag(TagClass.ContextSpecific, 3));
        }
        writer.PopSequence(tag);
    }
 
    internal static void Decode(ref System.Formats.Asn1.AsnValueReader reader, ReadOnlyMemory<byte> rebind, out TbsCertificateAsn decoded)
    {
        Decode(ref reader, Asn1Tag.Sequence, rebind, out decoded);
    }
 
    internal static void Decode(ref System.Formats.Asn1.AsnValueReader reader, Asn1Tag expectedTag, ReadOnlyMemory<byte> rebind, out TbsCertificateAsn decoded)
    {
        try
        {
            DecodeCore(ref reader, expectedTag, rebind, out decoded);
        }
        catch (AsnContentException inner)
        {
            throw new CryptographicException(System.SR.Cryptography_Der_Invalid_Encoding, inner);
        }
    }
 
    private static void DecodeCore(ref System.Formats.Asn1.AsnValueReader reader, Asn1Tag expectedTag, ReadOnlyMemory<byte> rebind, out TbsCertificateAsn decoded)
    {
        decoded = default(TbsCertificateAsn);
        System.Formats.Asn1.AsnValueReader reader2 = reader.ReadSequence(expectedTag);
        ReadOnlySpan<byte> span = rebind.Span;
        System.Formats.Asn1.AsnValueReader asnValueReader;
        if (reader2.HasData && reader2.PeekTag().HasSameClassAndValue(new Asn1Tag(TagClass.ContextSpecific, 0)))
        {
            asnValueReader = reader2.ReadSequence(new Asn1Tag(TagClass.ContextSpecific, 0));
            if (!asnValueReader.TryReadInt32(out decoded.Version))
            {
                asnValueReader.ThrowIfNotEmpty();
            }
            asnValueReader.ThrowIfNotEmpty();
        }
        else
        {
            System.Formats.Asn1.AsnValueReader asnValueReader2 = new System.Formats.Asn1.AsnValueReader(DefaultVersion, AsnEncodingRules.DER);
            if (!asnValueReader2.TryReadInt32(out decoded.Version))
            {
                asnValueReader2.ThrowIfNotEmpty();
            }
        }
        ReadOnlySpan<byte> value = reader2.ReadIntegerBytes();
        decoded.SerialNumber = (span.Overlaps(value, out var elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
        System.Security.Cryptography.Asn1.AlgorithmIdentifierAsn.Decode(ref reader2, rebind, out decoded.SignatureAlgorithm);
        if (!reader2.PeekTag().HasSameClassAndValue(new Asn1Tag(UniversalTagNumber.Sequence)))
        {
            throw new CryptographicException();
        }
        value = reader2.ReadEncodedValue();
        decoded.Issuer = (span.Overlaps(value, out elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
        ValidityAsn.Decode(ref reader2, rebind, out decoded.Validity);
        if (!reader2.PeekTag().HasSameClassAndValue(new Asn1Tag(UniversalTagNumber.Sequence)))
        {
            throw new CryptographicException();
        }
        value = reader2.ReadEncodedValue();
        decoded.Subject = (span.Overlaps(value, out elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
        System.Security.Cryptography.Asn1.SubjectPublicKeyInfoAsn.Decode(ref reader2, rebind, out decoded.SubjectPublicKeyInfo);
        int unusedBitCount;
        if (reader2.HasData && reader2.PeekTag().HasSameClassAndValue(new Asn1Tag(TagClass.ContextSpecific, 1)))
        {
            if (reader2.TryReadPrimitiveBitString(out unusedBitCount, out value, new Asn1Tag(TagClass.ContextSpecific, 1)))
            {
                decoded.IssuerUniqueId = (span.Overlaps(value, out elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
            }
            else
            {
                decoded.IssuerUniqueId = reader2.ReadBitString(out unusedBitCount, new Asn1Tag(TagClass.ContextSpecific, 1));
            }
        }
        if (reader2.HasData && reader2.PeekTag().HasSameClassAndValue(new Asn1Tag(TagClass.ContextSpecific, 2)))
        {
            if (reader2.TryReadPrimitiveBitString(out unusedBitCount, out value, new Asn1Tag(TagClass.ContextSpecific, 2)))
            {
                decoded.SubjectUniqueId = (span.Overlaps(value, out elementOffset) ? rebind.Slice(elementOffset, value.Length) : ((ReadOnlyMemory<byte>)value.ToArray()));
            }
            else
            {
                decoded.SubjectUniqueId = reader2.ReadBitString(out unusedBitCount, new Asn1Tag(TagClass.ContextSpecific, 2));
            }
        }
        if (reader2.HasData && reader2.PeekTag().HasSameClassAndValue(new Asn1Tag(TagClass.ContextSpecific, 3)))
        {
            asnValueReader = reader2.ReadSequence(new Asn1Tag(TagClass.ContextSpecific, 3));
            System.Formats.Asn1.AsnValueReader reader3 = asnValueReader.ReadSequence();
            List<X509ExtensionAsn> list = new List<X509ExtensionAsn>();
            while (reader3.HasData)
            {
                X509ExtensionAsn.Decode(ref reader3, rebind, out var decoded2);
                list.Add(decoded2);
            }
            decoded.Extensions = list.ToArray();
            asnValueReader.ThrowIfNotEmpty();
        }
        reader2.ThrowIfNotEmpty();
    }
}