internal ExcelVbaProtection(ExcelVbaProject project)
 {
     _project = project;
     VisibilityState = true;
 }
Beispiel #2
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 /// <summary>
 /// Create an empty VBA project.
 /// </summary>
 public void CreateVBAProject()
 {
     if (_vba != null || _package.Package.PartExists(new Uri(ExcelVbaProject.PartUri, UriKind.Relative)))
     {
         throw (new InvalidOperationException("VBA project already exists."));
     }
                 
     _vba = new ExcelVbaProject(this);
     _vba.Create();
 }
        internal byte[] SignProject(ExcelVbaProject proj)
        {
            if (!Certificate.HasPrivateKey)
            {
                //throw (new InvalidOperationException("The certificate doesn't have a private key"));
                Certificate = null;
                return null;
            }
            var hash = GetContentHash(proj);

            BinaryWriter bw = new BinaryWriter(new MemoryStream());
            bw.Write((byte)0x30); //Constructed Type 
            bw.Write((byte)0x32); //Total length
            bw.Write((byte)0x30); //Constructed Type 
            bw.Write((byte)0x0E); //Length SpcIndirectDataContent
            bw.Write((byte)0x06); //Oid Tag Indentifier 
            bw.Write((byte)0x0A); //Lenght OId
            bw.Write(new byte[] { 0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0x37, 0x02, 0x01, 0x1D }); //Encoded Oid 1.3.6.1.4.1.311.2.1.29
            bw.Write((byte)0x04);   //Octet String Tag Identifier
            bw.Write((byte)0x00);   //Zero length

            bw.Write((byte)0x30); //Constructed Type (DigestInfo)
            bw.Write((byte)0x20); //Length DigestInfo
            bw.Write((byte)0x30); //Constructed Type (Algorithm)
            bw.Write((byte)0x0C); //length AlgorithmIdentifier
            bw.Write((byte)0x06); //Oid Tag Indentifier 
            bw.Write((byte)0x08); //Lenght OId
            bw.Write(new byte[] { 0x2A, 0x86, 0x48, 0x86, 0xF7, 0x0D, 0x02, 0x05 }); //Encoded Oid for 1.2.840.113549.2.5 (AlgorithmIdentifier MD5)
            bw.Write((byte)0x05);   //Null type identifier
            bw.Write((byte)0x00);   //Null length
            bw.Write((byte)0x04);   //Octet String Identifier
            bw.Write((byte)hash.Length);   //Hash length
            bw.Write(hash);                //Content hash

            ContentInfo contentInfo = new ContentInfo(((MemoryStream)bw.BaseStream).ToArray());
            contentInfo.ContentType.Value = "1.3.6.1.4.1.311.2.1.4";
            Verifier = new SignedCms(contentInfo);
            var signer = new CmsSigner(Certificate);
            Verifier.ComputeSignature(signer, false);
            return Verifier.Encode();
        }
 private byte[] GetContentHash(ExcelVbaProject proj)
 {
     //MS-OVBA 2.4.2
     var enc = System.Text.Encoding.GetEncoding(proj.CodePage);
     BinaryWriter bw = new BinaryWriter(new MemoryStream());
     bw.Write(enc.GetBytes(proj.Name));
     bw.Write(enc.GetBytes(proj.Constants));
     foreach (var reference in proj.References)
     {
         if (reference.ReferenceRecordID == 0x0D)
         {
             bw.Write((byte)0x7B);
         }
         if (reference.ReferenceRecordID == 0x0E)
         {
             //var r = (ExcelVbaReferenceProject)reference;
             //BinaryWriter bwTemp = new BinaryWriter(new MemoryStream());
             //bwTemp.Write((uint)r.Libid.Length);
             //bwTemp.Write(enc.GetBytes(r.Libid));              
             //bwTemp.Write((uint)r.LibIdRelative.Length);
             //bwTemp.Write(enc.GetBytes(r.LibIdRelative));
             //bwTemp.Write(r.MajorVersion);
             //bwTemp.Write(r.MinorVersion);
             foreach (byte b in BitConverter.GetBytes((uint)reference.Libid.Length))  //Length will never be an UInt with 4 bytes that aren't 0 (> 0x00FFFFFF), so no need for the rest of the properties.
             {
                 if (b != 0)
                 {
                     bw.Write(b);
                 }
                 else
                 {
                     break;
                 }
             }
         }
     }
     foreach (var module in proj.Modules)
     {
         var lines = module.Code.Split(new char[] { '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
         foreach (var line in lines)
         {
             if (!line.StartsWith("attribute", true, null))
             {
                 bw.Write(enc.GetBytes(line));
             }
         }
     }
     var buffer = (bw.BaseStream as MemoryStream).ToArray();
     var hp = System.Security.Cryptography.MD5CryptoServiceProvider.Create();
     return hp.ComputeHash(buffer);
 }
        //Create Oid from a bytearray
        //private string ReadHash(byte[] content)
        //{
        //    StringBuilder builder = new StringBuilder();
        //    int offset = 0x6;
        //    if (0 < (content.Length))
        //    {
        //        byte num = content[offset];
        //        byte num2 = (byte)(num / 40);
        //        builder.Append(num2.ToString(null, null));
        //        builder.Append(".");
        //        num2 = (byte)(num % 40);
        //        builder.Append(num2.ToString(null, null));
        //        ulong num3 = 0L;
        //        for (int i = offset + 1; i < content.Length; i++)
        //        {
        //            num2 = content[i];
        //            num3 = (ulong)(ulong)(num3 << 7) + ((byte)(num2 & 0x7f));
        //            if ((num2 & 0x80) == 0)
        //            {
        //                builder.Append(".");
        //                builder.Append(num3.ToString(null, null));
        //                num3 = 0L;
        //            }
        //            //1.2.840.113549.2.5
        //        }
        //    }


        //    string oId = builder.ToString();

        //    return oId;
        //}
        internal void Save(ExcelVbaProject proj)
        {
            if (Certificate == null || Certificate.HasPrivateKey==false)    //No signature. Remove any Signature part
            {
                if (Part != null)
                {
                    foreach (var r in Part.GetRelationships())
                    {
                        Part.DeleteRelationship(r.Id);
                    }
                    Part.Package.DeletePart(Part.Uri);
                }
                return;
            }
            var ms = new MemoryStream();
            var bw = new BinaryWriter(ms);

            byte[] certStore = GetCertStore();

            byte[] cert = SignProject(proj);
            bw.Write((uint)cert.Length);
            bw.Write((uint)44);                  //?? 36 ref inside cert ??
            bw.Write((uint)certStore.Length);    //cbSigningCertStore
            bw.Write((uint)(cert.Length + 44));  //certStoreOffset
            bw.Write((uint)0);                   //cbProjectName
            bw.Write((uint)(cert.Length + certStore.Length + 44));    //projectNameOffset
            bw.Write((uint)0);    //fTimestamp
            bw.Write((uint)0);    //cbTimestampUrl
            bw.Write((uint)(cert.Length + certStore.Length + 44 + 2));    //timestampUrlOffset
            bw.Write(cert);
            bw.Write(certStore);
            bw.Write((ushort)0);//rgchProjectNameBuffer
            bw.Write((ushort)0);//rgchTimestampBuffer
            bw.Write((ushort)0);
            bw.Flush();

            var rel = proj.Part.GetRelationshipsByType(schemaRelVbaSignature).FirstOrDefault();
            if (Part == null)
            {

                if (rel != null)
                {
                    Uri = rel.TargetUri;
                    Part = proj._pck.GetPart(rel.TargetUri);
                }
                else
                {
                    Uri = new Uri("/xl/vbaProjectSignature.bin", UriKind.Relative);
                    Part = proj._pck.CreatePart(Uri, ExcelPackage.schemaVBASignature);
                }
            }
            if (rel == null)
            {
                proj.Part.CreateRelationship(PackUriHelper.ResolvePartUri(proj.Uri, Uri), TargetMode.Internal, schemaRelVbaSignature);                
            }
            var b = ms.ToArray();
            Part.GetStream(FileMode.Create).Write(b, 0, b.Length);            
        }