#if !BESTHTTP_DISABLE_ALTERNATE_SSL && (!UNITY_WEBGL || UNITY_EDITOR) #pragma warning disable using System; using System.Collections; using System.IO; using BestHTTP.SecureProtocol.Org.BouncyCastle.Asn1; using BestHTTP.SecureProtocol.Org.BouncyCastle.Asn1.Cms; using BestHTTP.SecureProtocol.Org.BouncyCastle.Asn1.X509; using BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto; using BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.Engines; using BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.IO; using BestHTTP.SecureProtocol.Org.BouncyCastle.Crypto.Signers; using BestHTTP.SecureProtocol.Org.BouncyCastle.Security; using BestHTTP.SecureProtocol.Org.BouncyCastle.Utilities; using BestHTTP.SecureProtocol.Org.BouncyCastle.X509; namespace BestHTTP.SecureProtocol.Org.BouncyCastle.Cms { /** * an expanded SignerInfo block from a CMS Signed message */ public class SignerInformation { private static readonly CmsSignedHelper Helper = CmsSignedHelper.Instance; private SignerID sid; private CmsProcessable content; private byte[] signature; private DerObjectIdentifier contentType; private byte[] calculatedDigest; private byte[] resultDigest; // Derived private Asn1.Cms.AttributeTable signedAttributeTable; private Asn1.Cms.AttributeTable unsignedAttributeTable; private readonly bool isCounterSignature; protected SignerInfo info; protected AlgorithmIdentifier digestAlgorithm; protected AlgorithmIdentifier encryptionAlgorithm; protected readonly Asn1Set signedAttributeSet; protected readonly Asn1Set unsignedAttributeSet; internal SignerInformation( SignerInfo info, DerObjectIdentifier contentType, CmsProcessable content, IDigestCalculator digestCalculator) { this.info = info; this.sid = new SignerID(); this.contentType = contentType; this.isCounterSignature = contentType == null; try { SignerIdentifier s = info.SignerID; if (s.IsTagged) { Asn1OctetString octs = Asn1OctetString.GetInstance(s.ID); sid.SubjectKeyIdentifier = octs.GetEncoded(); } else { Asn1.Cms.IssuerAndSerialNumber iAnds = Asn1.Cms.IssuerAndSerialNumber.GetInstance(s.ID); sid.Issuer = iAnds.Name; sid.SerialNumber = iAnds.SerialNumber.Value; } } catch (IOException) { throw new ArgumentException("invalid sid in SignerInfo"); } this.digestAlgorithm = info.DigestAlgorithm; this.signedAttributeSet = info.AuthenticatedAttributes; this.unsignedAttributeSet = info.UnauthenticatedAttributes; this.encryptionAlgorithm = info.DigestEncryptionAlgorithm; this.signature = (byte[])info.EncryptedDigest.GetOctets().Clone(); this.content = content; this.calculatedDigest = (digestCalculator != null) ? digestCalculator.GetDigest() : null; } /** * Protected constructor. In some cases clients have their own idea about how to encode * the signed attributes and calculate the signature. This constructor is to allow developers * to deal with that by extending off the class and overriding e.g. SignedAttributes property. * * @param baseInfo the SignerInformation to base this one on. */ protected SignerInformation(SignerInformation baseInfo) { this.info = baseInfo.info; this.content = baseInfo.content; this.contentType = baseInfo.contentType; this.isCounterSignature = baseInfo.IsCounterSignature; this.sid = baseInfo.sid; this.digestAlgorithm = info.DigestAlgorithm; this.signedAttributeSet = info.AuthenticatedAttributes; this.unsignedAttributeSet = info.UnauthenticatedAttributes; this.encryptionAlgorithm = info.DigestEncryptionAlgorithm; this.signature = (byte[])info.EncryptedDigest.GetOctets().Clone(); this.calculatedDigest = baseInfo.calculatedDigest; this.signedAttributeTable = baseInfo.signedAttributeTable; this.unsignedAttributeTable = baseInfo.unsignedAttributeTable; } public bool IsCounterSignature { get { return isCounterSignature; } } public DerObjectIdentifier ContentType { get { return contentType; } } public SignerID SignerID { get { return sid; } } /** * return the version number for this objects underlying SignerInfo structure. */ public int Version { get { return info.Version.IntValueExact; } } public AlgorithmIdentifier DigestAlgorithmID { get { return digestAlgorithm; } } /** * return the object identifier for the signature. */ public string DigestAlgOid { get { return digestAlgorithm.Algorithm.Id; } } /** * return the signature parameters, or null if there aren't any. */ public Asn1Object DigestAlgParams { get { Asn1Encodable ae = digestAlgorithm.Parameters; return ae == null ? null : ae.ToAsn1Object(); } } /** * return the content digest that was calculated during verification. */ public byte[] GetContentDigest() { if (resultDigest == null) { throw new InvalidOperationException("method can only be called after verify."); } return (byte[])resultDigest.Clone(); } public AlgorithmIdentifier EncryptionAlgorithmID { get { return encryptionAlgorithm; } } /** * return the object identifier for the signature. */ public string EncryptionAlgOid { get { return encryptionAlgorithm.Algorithm.Id; } } /** * return the signature/encryption algorithm parameters, or null if * there aren't any. */ public Asn1Object EncryptionAlgParams { get { Asn1Encodable ae = encryptionAlgorithm.Parameters; return ae == null ? null : ae.ToAsn1Object(); } } /** * return a table of the signed attributes - indexed by * the OID of the attribute. */ public Asn1.Cms.AttributeTable SignedAttributes { get { if (signedAttributeSet != null && signedAttributeTable == null) { signedAttributeTable = new Asn1.Cms.AttributeTable(signedAttributeSet); } return signedAttributeTable; } } /** * return a table of the unsigned attributes indexed by * the OID of the attribute. */ public Asn1.Cms.AttributeTable UnsignedAttributes { get { if (unsignedAttributeSet != null && unsignedAttributeTable == null) { unsignedAttributeTable = new Asn1.Cms.AttributeTable(unsignedAttributeSet); } return unsignedAttributeTable; } } /** * return the encoded signature */ public byte[] GetSignature() { return (byte[]) signature.Clone(); } /** * Return a SignerInformationStore containing the counter signatures attached to this * signer. If no counter signatures are present an empty store is returned. */ public SignerInformationStore GetCounterSignatures() { // TODO There are several checks implied by the RFC3852 comments that are missing /* The countersignature attribute MUST be an unsigned attribute; it MUST NOT be a signed attribute, an authenticated attribute, an unauthenticated attribute, or an unprotected attribute. */ Asn1.Cms.AttributeTable unsignedAttributeTable = UnsignedAttributes; if (unsignedAttributeTable == null) { return new SignerInformationStore(BestHTTP.SecureProtocol.Org.BouncyCastle.Utilities.Platform.CreateArrayList(0)); } IList counterSignatures = BestHTTP.SecureProtocol.Org.BouncyCastle.Utilities.Platform.CreateArrayList(); /* The UnsignedAttributes syntax is defined as a SET OF Attributes. The UnsignedAttributes in a signerInfo may include multiple instances of the countersignature attribute. */ Asn1EncodableVector allCSAttrs = unsignedAttributeTable.GetAll(CmsAttributes.CounterSignature); foreach (Asn1.Cms.Attribute counterSignatureAttribute in allCSAttrs) { /* A countersignature attribute can have multiple attribute values. The syntax is defined as a SET OF AttributeValue, and there MUST be one or more instances of AttributeValue present. */ Asn1Set values = counterSignatureAttribute.AttrValues; if (values.Count < 1) { // TODO Throw an appropriate exception? } foreach (Asn1Encodable asn1Obj in values) { /* Countersignature values have the same meaning as SignerInfo values for ordinary signatures, except that: 1. The signedAttributes field MUST NOT contain a content-type attribute; there is no content type for countersignatures. 2. The signedAttributes field MUST contain a message-digest attribute if it contains any other attributes. 3. The input to the message-digesting process is the contents octets of the DER encoding of the signatureValue field of the SignerInfo value with which the attribute is associated. */ SignerInfo si = SignerInfo.GetInstance(asn1Obj.ToAsn1Object()); string digestName = CmsSignedHelper.Instance.GetDigestAlgName(si.DigestAlgorithm.Algorithm.Id); counterSignatures.Add(new SignerInformation(si, null, null, new CounterSignatureDigestCalculator(digestName, GetSignature()))); } } return new SignerInformationStore(counterSignatures); } /** * return the DER encoding of the signed attributes. * @throws IOException if an encoding error occurs. */ public virtual byte[] GetEncodedSignedAttributes() { return signedAttributeSet == null ? null : signedAttributeSet.GetEncoded(Asn1Encodable.Der); } private bool DoVerify( AsymmetricKeyParameter key) { DerObjectIdentifier sigAlgOid = this.encryptionAlgorithm.Algorithm; Asn1Encodable sigParams = this.encryptionAlgorithm.Parameters; string digestName = Helper.GetDigestAlgName(this.EncryptionAlgOid); if (digestName.Equals(sigAlgOid.Id)) { digestName = Helper.GetDigestAlgName(this.DigestAlgOid); } IDigest digest = Helper.GetDigestInstance(digestName); ISigner sig; if (sigAlgOid.Equals(Asn1.Pkcs.PkcsObjectIdentifiers.IdRsassaPss)) { // RFC 4056 2.2 // When the id-RSASSA-PSS algorithm identifier is used for a signature, // the AlgorithmIdentifier parameters field MUST contain RSASSA-PSS-params. if (sigParams == null) throw new CmsException("RSASSA-PSS signature must specify algorithm parameters"); try { // TODO Provide abstract configuration mechanism // (via alternate SignerUtilities.GetSigner method taking ASN.1 params) Asn1.Pkcs.RsassaPssParameters pss = Asn1.Pkcs.RsassaPssParameters.GetInstance( sigParams.ToAsn1Object()); if (!pss.HashAlgorithm.Algorithm.Equals(this.digestAlgorithm.Algorithm)) throw new CmsException("RSASSA-PSS signature parameters specified incorrect hash algorithm"); if (!pss.MaskGenAlgorithm.Algorithm.Equals(Asn1.Pkcs.PkcsObjectIdentifiers.IdMgf1)) throw new CmsException("RSASSA-PSS signature parameters specified unknown MGF"); IDigest pssDigest = DigestUtilities.GetDigest(pss.HashAlgorithm.Algorithm); int saltLength = pss.SaltLength.IntValueExact; // RFC 4055 3.1 // The value MUST be 1, which represents the trailer field with hexadecimal value 0xBC if (!Asn1.Pkcs.RsassaPssParameters.DefaultTrailerField.Equals(pss.TrailerField)) throw new CmsException("RSASSA-PSS signature parameters must have trailerField of 1"); IAsymmetricBlockCipher rsa = new RsaBlindedEngine(); if (signedAttributeSet == null && calculatedDigest != null) { sig = PssSigner.CreateRawSigner(rsa, pssDigest, pssDigest, saltLength, PssSigner.TrailerImplicit); } else { sig = new PssSigner(rsa, pssDigest, saltLength); } } catch (Exception e) { throw new CmsException("failed to set RSASSA-PSS signature parameters", e); } } else { // TODO Probably too strong a check at the moment // if (sigParams != null) // throw new CmsException("unrecognised signature parameters provided"); string signatureName = digestName + "with" + Helper.GetEncryptionAlgName(this.EncryptionAlgOid); sig = Helper.GetSignatureInstance(signatureName); //sig = Helper.GetSignatureInstance(this.EncryptionAlgOid); //sig = SignerUtilities.GetSigner(sigAlgOid); } try { if (calculatedDigest != null) { resultDigest = calculatedDigest; } else { if (content != null) { content.Write(new DigestSink(digest)); } else if (signedAttributeSet == null) { // TODO Get rid of this exception and just treat content==null as empty not missing? throw new CmsException("data not encapsulated in signature - use detached constructor."); } resultDigest = DigestUtilities.DoFinal(digest); } } catch (IOException e) { throw new CmsException("can't process mime object to create signature.", e); } // RFC 3852 11.1 Check the content-type attribute is correct { Asn1Object validContentType = GetSingleValuedSignedAttribute( CmsAttributes.ContentType, "content-type"); if (validContentType == null) { if (!isCounterSignature && signedAttributeSet != null) throw new CmsException("The content-type attribute type MUST be present whenever signed attributes are present in signed-data"); } else { if (isCounterSignature) throw new CmsException("[For counter signatures,] the signedAttributes field MUST NOT contain a content-type attribute"); if (!(validContentType is DerObjectIdentifier)) throw new CmsException("content-type attribute value not of ASN.1 type 'OBJECT IDENTIFIER'"); DerObjectIdentifier signedContentType = (DerObjectIdentifier)validContentType; if (!signedContentType.Equals(contentType)) throw new CmsException("content-type attribute value does not match eContentType"); } } // RFC 3852 11.2 Check the message-digest attribute is correct { Asn1Object validMessageDigest = GetSingleValuedSignedAttribute( CmsAttributes.MessageDigest, "message-digest"); if (validMessageDigest == null) { if (signedAttributeSet != null) throw new CmsException("the message-digest signed attribute type MUST be present when there are any signed attributes present"); } else { if (!(validMessageDigest is Asn1OctetString)) { throw new CmsException("message-digest attribute value not of ASN.1 type 'OCTET STRING'"); } Asn1OctetString signedMessageDigest = (Asn1OctetString)validMessageDigest; if (!Arrays.AreEqual(resultDigest, signedMessageDigest.GetOctets())) throw new CmsException("message-digest attribute value does not match calculated value"); } } // RFC 3852 11.4 Validate countersignature attribute(s) { Asn1.Cms.AttributeTable signedAttrTable = this.SignedAttributes; if (signedAttrTable != null && signedAttrTable.GetAll(CmsAttributes.CounterSignature).Count > 0) { throw new CmsException("A countersignature attribute MUST NOT be a signed attribute"); } Asn1.Cms.AttributeTable unsignedAttrTable = this.UnsignedAttributes; if (unsignedAttrTable != null) { foreach (Asn1.Cms.Attribute csAttr in unsignedAttrTable.GetAll(CmsAttributes.CounterSignature)) { if (csAttr.AttrValues.Count < 1) throw new CmsException("A countersignature attribute MUST contain at least one AttributeValue"); // Note: We don't recursively validate the countersignature value } } } try { sig.Init(false, key); if (signedAttributeSet == null) { if (calculatedDigest != null) { if (sig is PssSigner) { sig.BlockUpdate(resultDigest, 0, resultDigest.Length); } else { // need to decrypt signature and check message bytes return VerifyDigest(resultDigest, key, this.GetSignature()); } } else if (content != null) { try { // TODO Use raw signature of the hash value instead content.Write(new SignerSink(sig)); } catch (SignatureException e) { throw new CmsStreamException("signature problem: " + e); } } } else { byte[] tmp = this.GetEncodedSignedAttributes(); sig.BlockUpdate(tmp, 0, tmp.Length); } return sig.VerifySignature(this.GetSignature()); } catch (InvalidKeyException e) { throw new CmsException("key not appropriate to signature in message.", e); } catch (IOException e) { throw new CmsException("can't process mime object to create signature.", e); } catch (SignatureException e) { throw new CmsException("invalid signature format in message: " + e.Message, e); } } private bool IsNull( Asn1Encodable o) { return (o is Asn1Null) || (o == null); } private DigestInfo DerDecode( byte[] encoding) { if (encoding[0] != (int)(Asn1Tags.Constructed | Asn1Tags.Sequence)) { throw new IOException("not a digest info object"); } DigestInfo digInfo = DigestInfo.GetInstance(Asn1Object.FromByteArray(encoding)); // length check to avoid Bleichenbacher vulnerability if (digInfo.GetEncoded().Length != encoding.Length) { throw new CmsException("malformed RSA signature"); } return digInfo; } private bool VerifyDigest( byte[] digest, AsymmetricKeyParameter key, byte[] signature) { string algorithm = Helper.GetEncryptionAlgName(this.EncryptionAlgOid); try { if (algorithm.Equals("RSA")) { IBufferedCipher c = CmsEnvelopedHelper.Instance.CreateAsymmetricCipher("RSA/ECB/PKCS1Padding"); c.Init(false, key); byte[] decrypt = c.DoFinal(signature); DigestInfo digInfo = DerDecode(decrypt); if (!digInfo.AlgorithmID.Algorithm.Equals(digestAlgorithm.Algorithm)) { return false; } if (!IsNull(digInfo.AlgorithmID.Parameters)) { return false; } byte[] sigHash = digInfo.GetDigest(); return Arrays.ConstantTimeAreEqual(digest, sigHash); } else if (algorithm.Equals("DSA")) { ISigner sig = SignerUtilities.GetSigner("NONEwithDSA"); sig.Init(false, key); sig.BlockUpdate(digest, 0, digest.Length); return sig.VerifySignature(signature); } else { throw new CmsException("algorithm: " + algorithm + " not supported in base signatures."); } } catch (SecurityUtilityException e) { throw e; } catch (GeneralSecurityException e) { throw new CmsException("Exception processing signature: " + e, e); } catch (IOException e) { throw new CmsException("Exception decoding signature: " + e, e); } } /** * verify that the given public key successfully handles and confirms the * signature associated with this signer. */ public bool Verify( AsymmetricKeyParameter pubKey) { if (pubKey.IsPrivate) throw new ArgumentException("Expected public key", "pubKey"); // Optional, but still need to validate if present GetSigningTime(); return DoVerify(pubKey); } /** * verify that the given certificate successfully handles and confirms * the signature associated with this signer and, if a signingTime * attribute is available, that the certificate was valid at the time the * signature was generated. */ public bool Verify( X509Certificate cert) { Asn1.Cms.Time signingTime = GetSigningTime(); if (signingTime != null) { cert.CheckValidity(signingTime.Date); } return DoVerify(cert.GetPublicKey()); } /** * Return the base ASN.1 CMS structure that this object contains. * * @return an object containing a CMS SignerInfo structure. */ public SignerInfo ToSignerInfo() { return info; } private Asn1Object GetSingleValuedSignedAttribute( DerObjectIdentifier attrOID, string printableName) { Asn1.Cms.AttributeTable unsignedAttrTable = this.UnsignedAttributes; if (unsignedAttrTable != null && unsignedAttrTable.GetAll(attrOID).Count > 0) { throw new CmsException("The " + printableName + " attribute MUST NOT be an unsigned attribute"); } Asn1.Cms.AttributeTable signedAttrTable = this.SignedAttributes; if (signedAttrTable == null) { return null; } Asn1EncodableVector v = signedAttrTable.GetAll(attrOID); switch (v.Count) { case 0: return null; case 1: Asn1.Cms.Attribute t = (Asn1.Cms.Attribute) v[0]; Asn1Set attrValues = t.AttrValues; if (attrValues.Count != 1) throw new CmsException("A " + printableName + " attribute MUST have a single attribute value"); return attrValues[0].ToAsn1Object(); default: throw new CmsException("The SignedAttributes in a signerInfo MUST NOT include multiple instances of the " + printableName + " attribute"); } } private Asn1.Cms.Time GetSigningTime() { Asn1Object validSigningTime = GetSingleValuedSignedAttribute( CmsAttributes.SigningTime, "signing-time"); if (validSigningTime == null) return null; try { return Asn1.Cms.Time.GetInstance(validSigningTime); } catch (ArgumentException) { throw new CmsException("signing-time attribute value not a valid 'Time' structure"); } } /** * Return a signer information object with the passed in unsigned * attributes replacing the ones that are current associated with * the object passed in. * * @param signerInformation the signerInfo to be used as the basis. * @param unsignedAttributes the unsigned attributes to add. * @return a copy of the original SignerInformationObject with the changed attributes. */ public static SignerInformation ReplaceUnsignedAttributes( SignerInformation signerInformation, Asn1.Cms.AttributeTable unsignedAttributes) { SignerInfo sInfo = signerInformation.info; Asn1Set unsignedAttr = null; if (unsignedAttributes != null) { unsignedAttr = new DerSet(unsignedAttributes.ToAsn1EncodableVector()); } return new SignerInformation( new SignerInfo( sInfo.SignerID, sInfo.DigestAlgorithm, sInfo.AuthenticatedAttributes, sInfo.DigestEncryptionAlgorithm, sInfo.EncryptedDigest, unsignedAttr), signerInformation.contentType, signerInformation.content, null); } /** * Return a signer information object with passed in SignerInformationStore representing counter * signatures attached as an unsigned attribute. * * @param signerInformation the signerInfo to be used as the basis. * @param counterSigners signer info objects carrying counter signature. * @return a copy of the original SignerInformationObject with the changed attributes. */ public static SignerInformation AddCounterSigners( SignerInformation signerInformation, SignerInformationStore counterSigners) { // TODO Perform checks from RFC 3852 11.4 SignerInfo sInfo = signerInformation.info; Asn1.Cms.AttributeTable unsignedAttr = signerInformation.UnsignedAttributes; Asn1EncodableVector v; if (unsignedAttr != null) { v = unsignedAttr.ToAsn1EncodableVector(); } else { v = new Asn1EncodableVector(); } Asn1EncodableVector sigs = new Asn1EncodableVector(); foreach (SignerInformation sigInf in counterSigners.GetSigners()) { sigs.Add(sigInf.ToSignerInfo()); } v.Add(new Asn1.Cms.Attribute(CmsAttributes.CounterSignature, new DerSet(sigs))); return new SignerInformation( new SignerInfo( sInfo.SignerID, sInfo.DigestAlgorithm, sInfo.AuthenticatedAttributes, sInfo.DigestEncryptionAlgorithm, sInfo.EncryptedDigest, new DerSet(v)), signerInformation.contentType, signerInformation.content, null); } } } #pragma warning restore #endif