// readSignedMessage reads a possibly signed message if mdin is non-zero then // that structure is updated and returned. Otherwise a fresh MessageDetails is // used. func readSignedMessage(packets *packet.Reader, mdin *MessageDetails, keyring KeyRing) (md *MessageDetails, err error) { if mdin == nil { mdin = new(MessageDetails) } md = mdin var p packet.Packet var h hash.Hash var wrappedHash hash.Hash FindLiteralData: for { p, err = packets.Next() if err != nil { return nil, err } switch p := p.(type) { case *packet.Compressed: packets.Push(p.Body) case *packet.OnePassSignature: if !p.IsLast { return nil, errors.UnsupportedError("nested signatures") } h, wrappedHash, err = hashForSignature(p.Hash, p.SigType) if err != nil { md = nil return } md.IsSigned = true md.SignedByKeyId = p.KeyId keys := keyring.KeysByIdUsage(p.KeyId, packet.KeyFlagSign) if len(keys) > 0 { md.SignedBy = &keys[0] } case *packet.LiteralData: md.LiteralData = p break FindLiteralData } } if md.SignedBy != nil { md.UnverifiedBody = &signatureCheckReader{packets, h, wrappedHash, md} } else if md.decrypted != nil { md.UnverifiedBody = checkReader{md} } else { md.UnverifiedBody = md.LiteralData.Body } return md, nil }