From 967627e58a3730d143aa0b15693a54bb93f0d0e8 Mon Sep 17 00:00:00 2001
From: orignal <i2porignal@yandex.ru>
Date: Mon, 12 Feb 2024 21:55:30 -0500
Subject: [PATCH] read correct reply length and handle reply codes

---
 libi2pd/Socks5.h | 106 ++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 81 insertions(+), 25 deletions(-)

diff --git a/libi2pd/Socks5.h b/libi2pd/Socks5.h
index 84a23997..d611bff3 100644
--- a/libi2pd/Socks5.h
+++ b/libi2pd/Socks5.h
@@ -29,7 +29,87 @@ namespace transport
 	const size_t SOCKS5_UDP_IPV4_REQUEST_HEADER_SIZE = 10;
 	const size_t SOCKS5_UDP_IPV6_REQUEST_HEADER_SIZE = 22;
 
+	const uint8_t SOCKS5_REPLY_SUCCESS = 0x00;
+	const uint8_t SOCKS5_REPLY_SERVER_FAILURE = 0x01;
+	const uint8_t SOCKS5_REPLY_CONNECTION_NOT_ALLOWED = 0x02;
+	const uint8_t SOCKS5_REPLY_NETWORK_UNREACHABLE = 0x03;
+	const uint8_t SOCKS5_REPLY_HOST_UNREACHABLE = 0x04;
+	const uint8_t SOCKS5_REPLY_CONNECTION_REFUSED = 0x05;
+	const uint8_t SOCKS5_REPLY_TTL_EXPIRED = 0x06;
+	const uint8_t SOCKS5_REPLY_COMMAND_NOT_SUPPORTED = 0x07;
+	const uint8_t SOCKS5_REPLY_ADDRESS_TYPE_NOT_SUPPORTED = 0x08;
+	
 	// SOCKS5 handshake
+	template<typename Socket, typename Handler>
+	void Socks5ReadReply (Socket& s, Handler handler)
+	{
+		auto readbuff = std::make_shared<std::vector<int8_t> >(258); // max possible
+		boost::asio::async_read(s, boost::asio::buffer(readbuff->data (), 5), boost::asio::transfer_all(), // read 4 bytes of header + first byte of address
+			[readbuff, &s, handler](const boost::system::error_code& ec, std::size_t transferred)
+			{
+				if (!ec)
+				{    
+				    if ((*readbuff)[1] == SOCKS5_REPLY_SUCCESS)
+				    {
+						size_t len = 0;
+						switch ((*readbuff)[3]) // ATYP
+						{
+							case SOCKS5_ATYP_IPV4: len = 3; break; // address length 4 bytes
+							case SOCKS5_ATYP_IPV6: len = 15; break; // address length 16 bytes
+							case SOCKS5_ATYP_NAME: len += (*readbuff)[4]; break; // first byte of address is length
+							default: ;
+						}	
+						if (len)
+						{
+							len += 2; // port
+							boost::asio::async_read(s, boost::asio::buffer(readbuff->data (), len), boost::asio::transfer_all(),
+								[readbuff, &s, handler](const boost::system::error_code& ec, std::size_t transferred)
+								{
+									if (!ec)
+										handler (boost::system::error_code ()); // success
+									else
+										handler (boost::asio::error::make_error_code (boost::asio::error::connection_aborted));
+								});		
+						}	
+						else
+							handler (boost::asio::error::make_error_code (boost::asio::error::fault)); // unknown address type 
+				    }
+				    else	
+						switch ((*readbuff)[1]) // REP
+						{
+							case SOCKS5_REPLY_SERVER_FAILURE:
+								handler (boost::asio::error::make_error_code (boost::asio::error::access_denied ));
+							break;	
+							case SOCKS5_REPLY_CONNECTION_NOT_ALLOWED:
+								handler (boost::asio::error::make_error_code (boost::asio::error::no_permission));
+							break;	
+							case SOCKS5_REPLY_HOST_UNREACHABLE:
+								handler (boost::asio::error::make_error_code (boost::asio::error::host_unreachable));
+							break;
+							case SOCKS5_REPLY_NETWORK_UNREACHABLE:
+								handler (boost::asio::error::make_error_code (boost::asio::error::network_unreachable));
+							break;
+							case SOCKS5_REPLY_CONNECTION_REFUSED:
+								handler (boost::asio::error::make_error_code (boost::asio::error::connection_refused));
+							break;
+							case SOCKS5_REPLY_TTL_EXPIRED:
+								handler (boost::asio::error::make_error_code (boost::asio::error::timed_out));
+							break;	
+							case SOCKS5_REPLY_COMMAND_NOT_SUPPORTED:
+								handler (boost::asio::error::make_error_code (boost::asio::error::operation_not_supported));
+							break;	
+							case SOCKS5_REPLY_ADDRESS_TYPE_NOT_SUPPORTED:
+								handler (boost::asio::error::make_error_code (boost::asio::error::no_protocol_option));
+							break;	
+							default:
+				        		handler (boost::asio::error::make_error_code (boost::asio::error::connection_aborted)); 
+						}
+				}
+				else
+				   handler (ec); 
+			});
+	}	
+	
 	template<typename Socket, typename Handler>
 	void Socks5Connect (Socket& s, Handler handler, std::shared_ptr<std::vector<uint8_t> > buff, uint16_t port)
 	{
@@ -44,31 +124,7 @@ namespace transport
 				{
 		            (void) transferred;
 					if (!ec)
-		            {
-		                auto readbuff = std::make_shared<std::vector<int8_t> >(262); // max possible
-		                boost::asio::async_read(s, boost::asio::buffer(readbuff->data (), 7), boost::asio::transfer_all(), // read min reply size
-				            [readbuff, &s, handler](const boost::system::error_code& ec, std::size_t transferred)
-		                    {
-		                        if (!ec)
-		                        {
-		                            if (!(*readbuff)[1]) // succeeded
-		                            {
-		                                boost::system::error_code ec;
-							            size_t moreBytes = s.available(ec);
-							            if (!ec && moreBytes) // read remaining portion of reply
-								            boost::asio::read (s, boost::asio::buffer(readbuff->data (), moreBytes), boost::asio::transfer_all (), ec);
-		                                if (!ec)
-		                                    handler (boost::system::error_code ());
-		                                else                                    
-		                                   handler (boost::asio::error::make_error_code (boost::asio::error::connection_aborted));  
-		                            }
-		                            else
-		                                handler (boost::asio::error::make_error_code (boost::asio::error::connection_refused)); 
-		                        }
-		                        else
-		                           handler (ec); 
-		                    });
-		            }
+		           		Socks5ReadReply (s, handler);
 					else
 		                handler (ec);
 				});