Logic error in .NET lib's CreateSensitiveComposite() when passing an externally-generated AES key

[crballentine-ess]

While trying to troubleshoot C# code that's calling TssObject.Create() to prepare an externally-generated AES key for TPM import, I found what I believe to be a logic error in CreateSensitiveComposite() which is called by Create().

I believe the bug to be in the else if (keyData.Length != keySize) in the code block below. That condition should use == rather than != otherwise a properly-sized keyData byte array will cause the else{} block to execute resulting in an exception.

        else if (pub.type == TpmAlgId.Symcipher)
        {
            var symDef = (SymDefObject)pub.parameters;
            if (symDef.Algorithm != TpmAlgId.Aes)
            {
                throw new ArgumentException("Unsupported symmetric algorithm");
            }

            int keySize = (symDef.KeyBits + 7) / 8;
            if (keyData == null)
            {
                keyData = Globs.GetRandomBytes(keySize);
            }
            else if (keyData.Length != keySize)
            {
                keyData = Globs.CopyData(keyData);
            }
            else
            {
                throw new ArgumentException("Wrong symmetric key length");
            }
            newSens = new Tpm2bSymKey(keyData);
        }