connection to oracle from mono on linux

crazyminsc · Post by **crazyminsc** » Wed 20 May 2009 15:48

hello we are considering to buy this product because of the actual state of default mono oracle client but we are experiencing some dificulties with both OCI and direct connection mode.

when using direct mode it burns up on:

Code: Select all

Unhandled Exception: System.Security.Cryptography.CryptographicException: This is a known weak, or semi-weak, key.
  at System.Security.Cryptography.DESTransform..ctor (System.Security.Cryptography.SymmetricAlgorithm symmAlgo, Boolean encryption, System.Byte[] key, System.Byte[] iv) [0x00000]
  at System.Security.Cryptography.DESCryptoServiceProvider.CreateEncryptor (System.Byte[] rgbKey, System.Byte[] rgbIV) [0x00000]

we havent' found much info about this issue on the net.

the OCI mode fails at:

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Unhandled Exception: System.InvalidOperationException: Can not obtain Oracle client information from registry. Make sure that Oracle Client Software is installed, or use Direct mode of connecting to server.
  at Devart.Data.Oracle.OracleHomeCollection.a () [0x00000]
  at Devart.Data.Oracle.OracleInternalConnection..ctor (Devart.Data.Oracle.x connectionOptions, Devart.Data.Oracle.OracleInternalConnection proxyConnection) [0x00000]

we have tried to create some mono registry keys but the error is the same.

note: when using the mono implementation of System.Data.OracleClient was just fair enough to export oracle variables and everything worked.

any ideas what are we doing wrong ?

thank you

Shalex · Post by **Shalex** » Thu 21 May 2009 09:36

We will investigate the problems and notify you about the results as soon as possible.

Shalex · Post by **Shalex** » Fri 22 May 2009 13:27

We support only the Direct mode under Mono (the OCI mode is not available).
1. Could you please tell us the Mono version, the Linux distribution type and its version you use?
2. Please post here more full call stack you obtain when the error occurs.

crazyminsc · Post by **crazyminsc** » Mon 25 May 2009 08:01

oh sorry i pasted only one part of this message. the full format looks like this

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Unhandled Exception: System.Security.Cryptography.CryptographicException: This is a known weak, or semi-weak, k  .
  at System.Security.Cryptography.DESTransform..ctor (System.Security.Cryptography.SymmetricAlgorithm symmAlgo,  oolean encryption, System.Byte[] key, System.Byte[] iv) [0x00000]
  at System.Security.Cryptography.DESCryptoServiceProvider.CreateEncryptor (System.Byte[] rgbKey, System.Byte[]  gbIV) [0x00000]
  at xc.r.b (System.Byte[] A_0) [0x00000]
  at xc.r.b (System.String A_0, System.String A_1) [0x00000]
  at xc.r.a () [0x00000]
  at xc.i.a () [0x00000]
  at Devart.Data.Oracle.ac.a (Devart.Data.Oracle.x A_0, Devart.Data.Oracle.at A_1) [0x00000]
  at Devart.Data.Oracle.OracleInternalConnection..ctor (Devart.Data.Oracle.x connectionOptions, Devart.Data.Ora  e.OracleInternalConnection proxyConnection) [0x00000]

we are using it on mono 2.4 build from source (just the released version, not svn) on CentOS 4/ RHEL 4 , but we are pretty sure it will it will do on other distributions as well. But i will test it for sure.

crazyminsc · Post by **crazyminsc** » Thu 28 May 2009 00:29

i have tried the opensuse 11.1 distribution with latest official mono packages and the error remains the same.

it throws the error:

Code: Select all

Unhandled Exception: System.Security.Cryptography.CryptographicException: This is a known weak, or semi-weak, key.
  at System.Security.Cryptography.DESTransform..ctor (System.Security.Cryptography.SymmetricAlgorithm symmAlgo, Boolean encryption, System.Byte[] key, System.Byte[] iv) [0x00000]
  at System.Security.Cryptography.DESCryptoServiceProvider.CreateEncryptor (System.Byte[] rgbKey, System.Byte[] rgbIV) [0x00000]
  at xc.r.b (System.Byte[] A_0) [0x00000]
  at xc.r.b (System.String A_0, System.String A_1) [0x00000]
  at xc.r.a () [0x00000]
  at xc.i.a () [0x00000]
  at Devart.Data.Oracle.ac.a (Devart.Data.Oracle.x A_0, Devart.Data.Oracle.at A_1) [0x00000]
  at Devart.Data.Oracle.OracleInternalConnection..ctor (Devart.Data.Oracle.x connectionOptions, Devart.Data.Oracle.OracleInternalConnection proxyConnection) [0x00000]

somewhere after it connects to the oracle database.

Thank you for any suggerstions

Shalex · Post by **Shalex** » Thu 28 May 2009 09:56

It seems like mono considers the Oracle key as a weak key. Could you please execute the following code?

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      DES des = new DESCryptoServiceProvider();
      des.Mode = CipherMode.CBC;
      des.IV = new byte[8];
      des.Padding = PaddingMode.Zeros;
      byte[] knownKey = new byte[]{1, 35, 69, 103, 137, 171, 205, 239};
      ICryptoTransform cryptoTransform = des.CreateEncryptor(knownKey, new byte[8]);

Please notify us about the results.

crazyminsc · Post by **crazyminsc** » Thu 28 May 2009 12:52

this code works without error.

Shalex · Post by **Shalex** » Fri 29 May 2009 13:33

We cannot reproduce the problem. Please try the sample we have sent you at your e-mail. Please notify us about the results.

crazyminsc · Post by **crazyminsc** » Mon 01 Jun 2009 15:28

solved. your program worked.

the problem was because of empty password in the configuration of our application. So the framework was encrypting empty passsword.

Thank you very for your time.

(yes i look like a complete fool

)