To fix the bug of OpenVPN 2.4.6 and particular version of kernel mode TAP driver on Linux, the TAP device must be up after the OpenVPN client is connected. However there is no direct push instruction to do so to OpenVPN client. Therefore we push the dummy IPv4 address (RFC7600) to the OpenVPN client to enforce the TAP driver UP state.
found by cppcheck
[src/Mayaqua/Mayaqua.c:753]: (style) Consecutive return, break, continue, goto or throw statements are unnecessary.
[src/Mayaqua/Mayaqua.c:484]: (style) The function 'IsUnicode' is never used.
[src/Mayaqua/Mayaqua.c:438]: (style) The function 'MayaquaDotNetMode' is never used.
[src/Mayaqua/Mayaqua.c:774]: (style) The function 'PrintOsInfo' is never used.
found by cppcheck
[src/Mayaqua/Cfg.c:669]: (style) Variable 'invalid_file' is assigned a value that is never used.
[src/Mayaqua/Cfg.c:2111]: (style) Variable 'v' is assigned a value that is never used.
[src/Mayaqua/Cfg.c:1114]: (style) The function 'CfgFolderToBufText' is never used.
[src/Mayaqua/Cfg.c:539]: (style) The function 'CfgRead' is never used.
[src/Mayaqua/Cfg.c:418]: (style) The function 'CfgSave' is never used.
[src/Mayaqua/Cfg.c:1425]: (style) The function 'CfgStrToType' is never used.
[src/Mayaqua/Cfg.c:708]: (style) The function 'CfgTest' is never used.
[src/Mayaqua/Cfg.c:704]: (style) The function 'CfgTest2' is never used.
[src/Mayaqua/Cfg.c:247]: (style) The function 'NewCfgRwW' is never used.
This allows an OpenVPN client to bypass a firewall which is aware of the protocol and is able to block it.
The XOR mask set on the server has to be the same on the client, otherwise it will not be able to connect with certain obfuscation modes.
A special OpenVPN client built with the "XOR patch" is required in order to use this function, because it has never been merged in the official OpenVPN repository.
Two parameters are added to the server configuration: "OpenVPNObfuscationMethod" and "OpenVPNObfuscationMask".
Their value can be retrieved with "OpenVpnObfuscationGet" and set with "OpenVpnObfuscationEnable" in the VPN Command Line Management Utility.
resolve possible null pointer dereference
found by cppcheck
[src/Cedar/Protocol.c:3138] -> [src/Cedar/Protocol.c:3071]: (warning) Either the condition 's!=NULL' is redundant or there is possible null pointer dereference: s.
[src/Cedar/Protocol.c:916]: (style) Variable 'save' is assigned a value that is never used.
[src/Cedar/Protocol.c:6242]: (style) Variable 'size' is assigned a value that is never used.
[src/Cedar/Protocol.c:778]: (style) Variable 'old_disable' is assigned a value that is never used.
[src/Cedar/Protocol.c:1021]: (style) Variable 'save' is assigned a value that is never used.
[src/Cedar/Protocol.c:3708]: (style) Variable 'is_vgc' is assigned a value that is never used.
[src/Cedar/Protocol.c:5785]: (style) Variable 's' is assigned a value that is never used.
[src/Cedar/Protocol.c:6164]: (style) The function 'SocksConnectEx' is never used.
[src/Cedar/Protocol.c:907]: (style) The function 'CompareNodeInfo' is never used.
[src/Cedar/Protocol.c:6968]: (style) The function 'ProxyConnect' is never used.
[src/Cedar/Protocol.c:3986]: (style) The function 'SecureDelete' is never used.
[src/Cedar/Protocol.c:4042]: (style) The function 'SecureEnum' is never used.
[src/Cedar/Protocol.c:4127]: (style) The function 'SecureWrite' is never used.
[src/Cedar/Protocol.c:6463]: (style) The function 'SocksConnect' is never used.
[src/Cedar/Protocol.c:7185]: (style) The function 'TcpConnectEx2' is never used.
[src/Cedar/Protocol.c:7206]: (style) The function 'TcpIpConnect' is never used.
