在Linux下使用subversion尝试链接VisualSVN server搭建的svn库，可能会报下面错误，

svn: OPTIONS of 'https://server.domain.local/svn/repo': SSL handshake failed: SSL error:
Key usage violation in certificate has been detected.
(https://server.domain.local)

google了这个问题，发现这个在VisualSVN的官网有说明，详细情况请参考https://www.visualsvn.com/support/topic/00056/。

遇到这个问题的原因是，

You may experience the issue if both of the following conditions are met:

• VisualSVN Server has a self-signed certificate applied and
• Subversion client is built against the GnuTLS library.

VisualSVN官网有下面说明，

GnuTLS library is an alternative to OpenSSL. Most Subversion clients for Windows are built against OpenSSL and are not affected by this issue. While some Subversion packages (available mostly on Linux-based operating systems such as Ubuntu and Debian) are built against GnuTLS and are affected.

解决该问题的方法是，

If you have to use a self-signed certificate please follow the instruction to generate a cerificate without specifying 'Key Usage' extension:

1. Add the following registry value to the Windows registry:

   • for 32-bit system:

     [HKEY_LOCAL_MACHINE\SOFTWARE\VisualSVN\VisualSVN Server]
     
     "CreateGnuTLSCompatibleCertificate"=dword:00000001
           

   • for 64-bit system:

     [HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\VisualSVN\VisualSVN Server]
     
     "CreateGnuTLSCompatibleCertificate"=dword:00000001
           

2. Start VisualSVN Server Manager.
3. Go to Action | Properties | Certificate.
4. Click Change certificate... and follow the wizard instructions to generate a new self-signed certificate.

The certificate will be generated without the 'Key Usage' extension and will be compatible both with GnuTLS and OpenSSL.