/// <summary>
/// Calculates sha1 mic based on the MIME body part.
/// </summary>
/// <param name="bodyPart"></param>
/// <param name="digestMethod"></param>
/// <returns></returns>
public static Digest CalculateMic(MimeEntity bodyPart, SMimeDigestMethod digestMethod)
{
try
{
byte[] digest;
using (var m = new MemoryStream())
{
bodyPart.WriteTo(m);
m.Seek(0, SeekOrigin.Begin);
digest = BcHelper.Hash(m.ToArray(), digestMethod.GetAlgorithm());
}
return(Digest.Of(digestMethod.GetDigestMethod(), digest));
}
catch (IOException e)
{
throw new InvalidOperationException("Unable to read data from digest input. " + e.Message, e);
}
catch (Exception e)
{
throw new InvalidOperationException("Unable to handle mime body part. " + e.Message, e);
}
}
/// <summary>
/// Receives an AS2 Message in the form of a map of headers together with the payload,
/// which is made available in an input stream
/// <p>If persisting message to the Message Repository fails, we have to return negative MDN.</p>
/// </summary>
/// <param name="httpHeaders">the http headers received</param>
/// <param name="mimeMessage">supplies the MIME message</param>
/// <returns>MDN object to signal if everything is ok or if some error occurred while receiving</returns>
public MimeMessage Receive(IHeaderDictionary httpHeaders, MimeMessage mimeMessage)
{
Logger.Debug("Receiving message ..");
SMimeReader sMimeReader = new SMimeReader(mimeMessage);
// Get timestamp using signature as input
Timestamp t2 = this.timestampProvider.Generate(sMimeReader.GetSignature(), Direction.IN);
// Initiate MDN
MdnBuilder mdnBuilder = MdnBuilder.NewInstance(mimeMessage);
mdnBuilder.AddHeader(MdnHeader.Date, t2.GetDate());
// Extract Message-ID
TransmissionIdentifier transmissionIdentifier =
TransmissionIdentifier.FromHeader(httpHeaders[As2Header.MessageId]);
mdnBuilder.AddHeader(MdnHeader.OriginalMessageId, httpHeaders[As2Header.MessageId]);
// Extract signed digest and digest algorithm
SMimeDigestMethod digestMethod = sMimeReader.GetDigestMethod();
// Extract content headers
byte[] headerBytes = sMimeReader.GetBodyHeader();
Stream bodyStream = sMimeReader.GetBodyInputStream();
byte[] bodyBytes = bodyStream.ToBuffer();
mdnBuilder.AddHeader(MdnHeader.OriginalContentHeader, headerBytes);
// Extract SBDH
Mx.Peppol.Common.Model.Header header;
bodyStream.Seek(0, SeekOrigin.Begin);
using (var sbdReader = SbdReader.NewInstance(bodyStream))
{
header = sbdReader.Header;
// Perform validation of SBDH
this.transmissionVerifier.Verify(header, Direction.IN);
// Extract "fresh" InputStream
using (Stream payloadInputStream = sMimeReader.GetBodyInputStream())
{
// Persist content
this.persisterHandler.Persist(
transmissionIdentifier,
header,
new UnclosableInputStream(payloadInputStream));
}
// Fetch calculated digest
var s = SHA1.Create();
var hash = s.ComputeHash(headerBytes.Concat(bodyBytes).ToArray());
Digest calculatedDigest = Digest.Of(DigestMethod.Sha1, hash);
mdnBuilder.AddHeader(MdnHeader.ReceivedContentMic, new Mic(calculatedDigest));
var check = this.VerifySignature(mimeMessage.Body as MultipartSigned, out var signatures);
if (!check || signatures.Count != 1)
{
throw new NotSupportedException("Firma non valida");
}
var signature = signatures[0];
var certificate = signature.SignerCertificate as SecureMimeDigitalCertificate;
Debug.Assert(certificate != null, nameof(certificate) + " != null");
this.certificateValidator.Validate(Service.Ap, certificate.Certificate);
// Create receipt (MDN)
mdnBuilder.AddHeader(MdnHeader.Disposition, Disposition.Processed);
MimeMessage mdn = this.sMimeMessageFactory.CreateSignedMimeMessage(mdnBuilder.Build(), digestMethod);
mdn.Headers.Add(As2Header.As2Version, As2Header.Version);
mdn.Headers.Add(As2Header.As2From, httpHeaders[As2Header.As2To]);
mdn.Headers.Add(As2Header.As2To, httpHeaders[As2Header.As2From]);
return(mdn);
}
}
