A detailed introduction to the authentication package and code of the mysql protocol

git

https://github.com/sea-boat/mysql-protocol

Overview

Mysql client requires an interactive process to log in to the mysql server. First, the server sends an initial handshake packet to the client. After receiving the handshake packet, the client returns an authentication packet to the server. As follows, the authentication package is analyzed here.

client                 server
   |-------connect------>|
   |                     |
   |<-----handshake------|
   |                     |
   |---authentication--->|
   |                     |

mysql communication message structure

##PayloadAuthentication Package

4              capability flags, CLIENT_PROTOCOL_41 always set
4              max-packet size
1              character set
string[23]     reserved (all [0])
string[NUL]    username
  if capabilities & CLIENT_PLUGIN_AUTH_LENENC_CLIENT_DATA {
lenenc-int     length of auth-response
string[n]      auth-response
  } else if capabilities & CLIENT_SECURE_CONNECTION {
1              length of auth-response
string[n]      auth-response
  } else {
string[NUL]    auth-response
  }
  if capabilities & CLIENT_CONNECT_WITH_DB {
string[NUL]    database
  }
  if capabilities & CLIENT_PLUGIN_AUTH {
string[NUL]    auth plugin name
  }
  if capabilities & CLIENT_CONNECT_ATTRS {
lenenc-int     length of all key-values
lenenc-str     key
lenenc-str     value
   if-more data in 'length of all key-values', more keys and value pairs
  }

More details: http://dev.mysql.com/doc/internals/en/connection-phase-packets.html#packet-Protocol::HandshakeResponse

Authentication package operation

1. Authentication package class

/**
 * 
 * @author seaboat
 * @date 2016-09-25
 * @version 1.0
 * <pre class="brush:php;toolbar:false"><b>email: </b>849586227@qq.com

 * 

blog: http://www.php.cn/;/pre>
 * 
mysql auth packet.
 */public class AuthPacket extends MySQLPacket {
    private static final byte[] FILLER = new byte[23];    
    public long clientFlags;    
    public long maxPacketSize;    
    public int charsetIndex;    
    public byte[] extra;    
    public String user;    
    public byte[] password;    
    public String database;    
    public void read(byte[] data) {
        MySQLMessage mm = new MySQLMessage(data);
        packetLength = mm.readUB3();
        packetId = mm.read();
        clientFlags = mm.readUB4();
        maxPacketSize = mm.readUB4();
        charsetIndex = (mm.read() & 0xff);        
        int current = mm.position();        
        int len = (int) mm.readLength();        
        if (len > 0 && len 

Encryption and decryption tool

/**
 * 
 * @author seaboat
 * @date 2016-09-25
 * @version 1.0
 * <pre class="brush:php;toolbar:false"><b>email: </b>849586227@qq.com
 * 
<b>blog: </b>http://www.php.cn/;/pre>
 * <p>a security util .</p>
 */public class SecurityUtil {

    public static final byte[] scramble411(byte[] pass, byte[] seed)            
    throws NoSuchAlgorithmException {
        MessageDigest md = MessageDigest.getInstance("SHA-1");        
        byte[] pass1 = md.digest(pass);
        md.reset();        
        byte[] pass2 = md.digest(pass1);
        md.reset();
        md.update(seed);        
        byte[] pass3 = md.digest(pass2);        
        for (int i = 0; i 

 Test class

/**
 * 
 * @author seaboat
 * @date 2016-09-25
 * @version 1.0
 * <pre class="brush:php;toolbar:false"><b>email: </b>849586227@qq.com
 * 
<b>blog: </b>http://www.php.cn/;/pre>
 * <p>test auth packet.</p>
 */public class AuthPacketTest {
    @Test
    public void produce() {        
    // handshake packet's rand1 and rand2
        byte[] rand1 = RandomUtil.randomBytes(8);        
        byte[] rand2 = RandomUtil.randomBytes(12);        
        byte[] seed = new byte[rand1.length + rand2.length];
        System.arraycopy(rand1, 0, seed, 0, rand1.length);
        System.arraycopy(rand2, 0, seed, rand1.length, rand2.length);

        AuthPacket auth = new AuthPacket();
        auth.packetId = 0;
        auth.clientFlags = getClientCapabilities();
        auth.maxPacketSize = 1024 * 1024 * 16;
        auth.user = "seaboat";        try {
            auth.password = SecurityUtil
                    .scramble411("seaboat".getBytes(), seed);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        auth.database = "test";

        ByteBuffer buffer = ByteBuffer.allocate(256);
        auth.write(buffer);
        buffer.flip();        byte[] bytes = new byte[buffer.remaining()];
        buffer.get(bytes, 0, bytes.length);
        String result = HexUtil.Bytes2HexString(bytes);
        System.out.println(result);
        assertTrue(Integer.valueOf(result.substring(0, 2), 16) == result
                .length() / 2 - 4);

        AuthPacket auth2 = new AuthPacket();
        auth2.read(bytes);
        assertTrue(auth2.database.equals("test"));
    }    protected int getClientCapabilities() {        
    int flag = 0;
        flag |= Capabilities.CLIENT_LONG_PASSWORD;
        flag |= Capabilities.CLIENT_FOUND_ROWS;
        flag |= Capabilities.CLIENT_LONG_FLAG;
        flag |= Capabilities.CLIENT_CONNECT_WITH_DB;
        flag |= Capabilities.CLIENT_ODBC;
        flag |= Capabilities.CLIENT_IGNORE_SPACE;
        flag |= Capabilities.CLIENT_PROTOCOL_41;
        flag |= Capabilities.CLIENT_INTERACTIVE;
        flag |= Capabilities.CLIENT_IGNORE_SIGPIPE;
        flag |= Capabilities.CLIENT_TRANSACTIONS;
        flag |= Capabilities.CLIENT_SECURE_CONNECTION;        
        return flag;
    }
}

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