diff options
Diffstat (limited to 'crypto/src/asn1/ASN1StreamParser.cs')
| -rw-r--r-- | crypto/src/asn1/ASN1StreamParser.cs | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/crypto/src/asn1/ASN1StreamParser.cs b/crypto/src/asn1/ASN1StreamParser.cs new file mode 100644 index 000000000..a5e6e3164 --- /dev/null +++ b/crypto/src/asn1/ASN1StreamParser.cs @@ -0,0 +1,235 @@ +using System; +using System.IO; + +namespace Org.BouncyCastle.Asn1 +{ + public class Asn1StreamParser + { + private readonly Stream _in; + private readonly int _limit; + + private readonly byte[][] tmpBuffers; + + public Asn1StreamParser( + Stream inStream) + : this(inStream, Asn1InputStream.FindLimit(inStream)) + { + } + + public Asn1StreamParser( + Stream inStream, + int limit) + { + if (!inStream.CanRead) + throw new ArgumentException("Expected stream to be readable", "inStream"); + + this._in = inStream; + this._limit = limit; + this.tmpBuffers = new byte[16][]; + } + + public Asn1StreamParser( + byte[] encoding) + : this(new MemoryStream(encoding, false), encoding.Length) + { + } + + internal IAsn1Convertible ReadIndef(int tagValue) + { + // Note: INDEF => CONSTRUCTED + + // TODO There are other tags that may be constructed (e.g. BIT_STRING) + switch (tagValue) + { + case Asn1Tags.External: + return new DerExternalParser(this); + case Asn1Tags.OctetString: + return new BerOctetStringParser(this); + case Asn1Tags.Sequence: + return new BerSequenceParser(this); + case Asn1Tags.Set: + return new BerSetParser(this); + default: + throw new Asn1Exception("unknown BER object encountered: 0x" + tagValue.ToString("X")); + } + } + + internal IAsn1Convertible ReadImplicit(bool constructed, int tag) + { + if (_in is IndefiniteLengthInputStream) + { + if (!constructed) + throw new IOException("indefinite length primitive encoding encountered"); + + return ReadIndef(tag); + } + + if (constructed) + { + switch (tag) + { + case Asn1Tags.Set: + return new DerSetParser(this); + case Asn1Tags.Sequence: + return new DerSequenceParser(this); + case Asn1Tags.OctetString: + return new BerOctetStringParser(this); + } + } + else + { + switch (tag) + { + case Asn1Tags.Set: + throw new Asn1Exception("sequences must use constructed encoding (see X.690 8.9.1/8.10.1)"); + case Asn1Tags.Sequence: + throw new Asn1Exception("sets must use constructed encoding (see X.690 8.11.1/8.12.1)"); + case Asn1Tags.OctetString: + return new DerOctetStringParser((DefiniteLengthInputStream)_in); + } + } + + throw new Asn1Exception("implicit tagging not implemented"); + } + + internal Asn1Object ReadTaggedObject(bool constructed, int tag) + { + if (!constructed) + { + // Note: !CONSTRUCTED => IMPLICIT + DefiniteLengthInputStream defIn = (DefiniteLengthInputStream)_in; + return new DerTaggedObject(false, tag, new DerOctetString(defIn.ToArray())); + } + + Asn1EncodableVector v = ReadVector(); + + if (_in is IndefiniteLengthInputStream) + { + return v.Count == 1 + ? new BerTaggedObject(true, tag, v[0]) + : new BerTaggedObject(false, tag, BerSequence.FromVector(v)); + } + + return v.Count == 1 + ? new DerTaggedObject(true, tag, v[0]) + : new DerTaggedObject(false, tag, DerSequence.FromVector(v)); + } + + public virtual IAsn1Convertible ReadObject() + { + int tag = _in.ReadByte(); + if (tag == -1) + return null; + + // turn of looking for "00" while we resolve the tag + Set00Check(false); + + // + // calculate tag number + // + int tagNo = Asn1InputStream.ReadTagNumber(_in, tag); + + bool isConstructed = (tag & Asn1Tags.Constructed) != 0; + + // + // calculate length + // + int length = Asn1InputStream.ReadLength(_in, _limit); + + if (length < 0) // indefinite length method + { + if (!isConstructed) + throw new IOException("indefinite length primitive encoding encountered"); + + IndefiniteLengthInputStream indIn = new IndefiniteLengthInputStream(_in, _limit); + Asn1StreamParser sp = new Asn1StreamParser(indIn, _limit); + + if ((tag & Asn1Tags.Application) != 0) + { + return new BerApplicationSpecificParser(tagNo, sp); + } + + if ((tag & Asn1Tags.Tagged) != 0) + { + return new BerTaggedObjectParser(true, tagNo, sp); + } + + return sp.ReadIndef(tagNo); + } + else + { + DefiniteLengthInputStream defIn = new DefiniteLengthInputStream(_in, length); + + if ((tag & Asn1Tags.Application) != 0) + { + return new DerApplicationSpecific(isConstructed, tagNo, defIn.ToArray()); + } + + if ((tag & Asn1Tags.Tagged) != 0) + { + return new BerTaggedObjectParser(isConstructed, tagNo, new Asn1StreamParser(defIn)); + } + + if (isConstructed) + { + // TODO There are other tags that may be constructed (e.g. BitString) + switch (tagNo) + { + case Asn1Tags.OctetString: + // + // yes, people actually do this... + // + return new BerOctetStringParser(new Asn1StreamParser(defIn)); + case Asn1Tags.Sequence: + return new DerSequenceParser(new Asn1StreamParser(defIn)); + case Asn1Tags.Set: + return new DerSetParser(new Asn1StreamParser(defIn)); + case Asn1Tags.External: + return new DerExternalParser(new Asn1StreamParser(defIn)); + default: + // TODO Add DerUnknownTagParser class? + return new DerUnknownTag(true, tagNo, defIn.ToArray()); + } + } + + // Some primitive encodings can be handled by parsers too... + switch (tagNo) + { + case Asn1Tags.OctetString: + return new DerOctetStringParser(defIn); + } + + try + { + return Asn1InputStream.CreatePrimitiveDerObject(tagNo, defIn, tmpBuffers); + } + catch (ArgumentException e) + { + throw new Asn1Exception("corrupted stream detected", e); + } + } + } + + private void Set00Check( + bool enabled) + { + if (_in is IndefiniteLengthInputStream) + { + ((IndefiniteLengthInputStream) _in).SetEofOn00(enabled); + } + } + + internal Asn1EncodableVector ReadVector() + { + Asn1EncodableVector v = new Asn1EncodableVector(); + + IAsn1Convertible obj; + while ((obj = ReadObject()) != null) + { + v.Add(obj.ToAsn1Object()); + } + + return v; + } + } +} |