This commit adds a protocol interface to the server, its purpose is to manage TCP connections and the various third-party protocols.
More specifically, ProtoHandleConnection() takes care of exchanging the packets between the local and remote endpoint; the protocol implementation only has to parse them and act accordingly.
The interface knows which protocol is the connection for by calling IsPacketForMe(), a function implemented for each protocol.
A race condition in the DHCP server caused it to offer the same IP address to multiple clients when they connected at the same time, because an offered IP address was considered free until the final step (DHCP_ACK).
This commit introduces a list to keep track of the pending leases created during DHCP_OFFER, so that an IP address is guaranteed to be offered to a single client.
StrCat() appends a string to an already existing string. In order to know where the existing string ends, it uses StrLen() which in turn uses strlen(), a function considered unsafe because it doesn't stop until it finds the null character.
Since the string was allocated but not initialized, StrCat() was either:
- Working correctly.
- Copying only a part of the string.
- Making the program crash via strlen().
The fix consists in using StrCpy(), which starts writing at the beginning of the string.
found by cppcheck
[src/Cedar/DDNS.c:656]: (style) Condition 'ret==NULL' is always true
[src/Cedar/DDNS.c:515] -> [src/Cedar/DDNS.c:640]: (style) The expression 'use_https == false' is always true because 'use_https' and 'false' represent the same value.
[src/Cedar/DDNS.c:516] -> [src/Cedar/DDNS.c:648]: (style) The expression 'no_cert_verify == false' is always true because 'no_cert_verify' and 'false' represent the same value.
[src/Cedar/DDNS.c:816] -> [src/Cedar/DDNS.c:860]: (style) The expression 'no_cert_verify == false' is always true because 'no_cert_verify' and 'false' represent the same value.
[src/Cedar/DDNS.c:530]: (style) Variable 'use_vgs' is assigned a value that is never used.
[src/Cedar/DDNS.c:497]: (style) The function 'DCUpdateNow' is never used.
found by cppcheck
[src/Cedar/Account.c:523]: (style) The function 'GetUserPolicy' is never used.
[src/Cedar/Account.c:163]: (style) The function 'NormalizePolicyName' is never used.
found by cppcheck
[src/Cedar/Command.c:23220] -> [src/Cedar/Command.c:23232]: (style) Variable 'len' is reassigned a value before the old one has been used.
found by cppcheck
[src/Cedar/CM.c:4509]: (style) Variable 'easy' is assigned a value that is never used.
[src/Cedar/CM.c:4547]: (style) Variable 'hub_name' is assigned a value that is never used.
[src/Cedar/CM.c:4609]: (style) Variable 'is_account' is assigned a value that is never used.
[src/Cedar/CM.c:8545]: (style) The function 'CmLoadK' is never used.
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.
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.
1.0.0.1 is a real IP address, owned by CloudFlare and used for their DNS service.
This commit changes the IP address we push to 192.0.0.8, which is defined in RFC7600 as dummy IPv4 address.
found by cppcheck
[src/Cedar/Proto_IkePacket.c:958]: (style) The function 'IkeNewCertPayload' is never used.
[src/Cedar/Proto_IkePacket.c:942]: (style) The function 'IkeNewCertRequestPayload' is never used.
[src/Cedar/Proto_IkePacket.c:875]: (style) The function 'IkeNewNoticeErrorInvalidExchangeTypePayload' is never used.
[src/Cedar/Proto_IkePacket.c:2542]: (style) The function 'IkeNewSpi' is never used.
[src/Cedar/Proto_IkePacket.c:142]: (style) The function 'IkePhase1CryptIdToKeySize' is never used.
[src/Cedar/Proto_IkePacket.c:157]: (style) The function 'IkePhase2CryptIdToKeySize' is never used.
[src/Cedar/Proto_IkePacket.c:172]: (style) The function 'IkeStrToPhase1CryptId' is never used.
[src/Cedar/Proto_IkePacket.c:187]: (style) The function 'IkeStrToPhase1HashId' is never used.
[src/Cedar/Proto_IkePacket.c:196]: (style) The function 'IkeStrToPhase2CryptId' is never used.
[src/Cedar/Proto_IkePacket.c:211]: (style) The function 'IkeStrToPhase2HashId' is never used.
[src/Cedar/Proto_IkePacket.c:2168]: (style) Condition 'b==NULL' is always true
