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// Go MySQL Driver - A MySQL-Driver for Go's database/sql package
//
// Copyright 2018 The Go-MySQL-Driver Authors. All rights reserved.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this file,
// You can obtain one at http://mozilla.org/MPL/2.0/.
package mysql
import (
"crypto/rand"
"crypto/rsa"
"crypto/sha1"
"crypto/sha256"
"crypto/x509"
"encoding/pem"
"sync"
)
// server pub keys registry
var (
serverPubKeyLock sync.RWMutex
serverPubKeyRegistry map[string]*rsa.PublicKey
)
// RegisterServerPubKey registers a server RSA public key which can be used to
// send data in a secure manner to the server without receiving the public key
// in a potentially insecure way from the server first.
// Registered keys can afterwards be used adding serverPubKey=<name> to the DSN.
//
// Note: The provided rsa.PublicKey instance is exclusively owned by the driver
// after registering it and may not be modified.
//
// data, err := ioutil.ReadFile("mykey.pem")
// if err != nil {
// log.Fatal(err)
// }
//
// block, _ := pem.Decode(data)
// if block == nil || block.Type != "PUBLIC KEY" {
// log.Fatal("failed to decode PEM block containing public key")
// }
//
// pub, err := x509.ParsePKIXPublicKey(block.Bytes)
// if err != nil {
// log.Fatal(err)
// }
//
// if rsaPubKey, ok := pub.(*rsa.PublicKey); ok {
// mysql.RegisterServerPubKey("mykey", rsaPubKey)
// } else {
// log.Fatal("not a RSA public key")
// }
//
func RegisterServerPubKey(name string, pubKey *rsa.PublicKey) {
serverPubKeyLock.Lock()
if serverPubKeyRegistry == nil {
serverPubKeyRegistry = make(map[string]*rsa.PublicKey)
}
serverPubKeyRegistry[name] = pubKey
serverPubKeyLock.Unlock()
}
// DeregisterServerPubKey removes the public key registered with the given name.
func DeregisterServerPubKey(name string) {
serverPubKeyLock.Lock()
if serverPubKeyRegistry != nil {
delete(serverPubKeyRegistry, name)
}
serverPubKeyLock.Unlock()
}
func getServerPubKey(name string) (pubKey *rsa.PublicKey) {
serverPubKeyLock.RLock()
if v, ok := serverPubKeyRegistry[name]; ok {
pubKey = v
}
serverPubKeyLock.RUnlock()
return
}
// Hash password using pre 4.1 (old password) method
// https://github.com/atcurtis/mariadb/blob/master/mysys/my_rnd.c
type myRnd struct {
seed1, seed2 uint32
}
const myRndMaxVal = 0x3FFFFFFF
// Pseudo random number generator
func newMyRnd(seed1, seed2 uint32) *myRnd {
return &myRnd{
seed1: seed1 % myRndMaxVal,
seed2: seed2 % myRndMaxVal,
}
}
// Tested to be equivalent to MariaDB's floating point variant
// http://play.golang.org/p/QHvhd4qved
// http://play.golang.org/p/RG0q4ElWDx
func (r *myRnd) NextByte() byte {
r.seed1 = (r.seed1*3 + r.seed2) % myRndMaxVal
r.seed2 = (r.seed1 + r.seed2 + 33) % myRndMaxVal
return byte(uint64(r.seed1) * 31 / myRndMaxVal)
}
// Generate binary hash from byte string using insecure pre 4.1 method
func pwHash(password []byte) (result [2]uint32) {
var add uint32 = 7
var tmp uint32
result[0] = 1345345333
result[1] = 0x12345671
for _, c := range password {
// skip spaces and tabs in password
if c == ' ' || c == '\t' {
continue
}
tmp = uint32(c)
result[0] ^= (((result[0] & 63) + add) * tmp) + (result[0] << 8)
result[1] += (result[1] << 8) ^ result[0]
add += tmp
}
// Remove sign bit (1<<31)-1)
result[0] &= 0x7FFFFFFF
result[1] &= 0x7FFFFFFF
return
}
// Hash password using insecure pre 4.1 method
func scrambleOldPassword(scramble []byte, password string) []byte {
if len(password) == 0 {
return nil
}
scramble = scramble[:8]
hashPw := pwHash([]byte(password))
hashSc := pwHash(scramble)
r := newMyRnd(hashPw[0]^hashSc[0], hashPw[1]^hashSc[1])
var out [8]byte
for i := range out {
out[i] = r.NextByte() + 64
}
mask := r.NextByte()
for i := range out {
out[i] ^= mask
}
return out[:]
}
// Hash password using 4.1+ method (SHA1)
func scramblePassword(scramble []byte, password string) []byte {
if len(password) == 0 {
return nil
}
// stage1Hash = SHA1(password)
crypt := sha1.New()
crypt.Write([]byte(password))
stage1 := crypt.Sum(nil)
// scrambleHash = SHA1(scramble + SHA1(stage1Hash))
// inner Hash
crypt.Reset()
crypt.Write(stage1)
hash := crypt.Sum(nil)
// outer Hash
crypt.Reset()
crypt.Write(scramble)
crypt.Write(hash)
scramble = crypt.Sum(nil)
// token = scrambleHash XOR stage1Hash
for i := range scramble {
scramble[i] ^= stage1[i]
}
return scramble
}
// Hash password using MySQL 8+ method (SHA256)
func scrambleSHA256Password(scramble []byte, password string) []byte {
if len(password) == 0 {
return nil
}
// XOR(SHA256(password), SHA256(SHA256(SHA256(password)), scramble))
crypt := sha256.New()
crypt.Write([]byte(password))
message1 := crypt.Sum(nil)
crypt.Reset()
crypt.Write(message1)
message1Hash := crypt.Sum(nil)
crypt.Reset()
crypt.Write(message1Hash)
crypt.Write(scramble)
message2 := crypt.Sum(nil)
for i := range message1 {
message1[i] ^= message2[i]
}
return message1
}
func encryptPassword(password string, seed []byte, pub *rsa.PublicKey) ([]byte, error) {
plain := make([]byte, len(password)+1)
copy(plain, password)
for i := range plain {
j := i % len(seed)
plain[i] ^= seed[j]
}
sha1 := sha1.New()
return rsa.EncryptOAEP(sha1, rand.Reader, pub, plain, nil)
}
func (mc *mysqlConn) sendEncryptedPassword(seed []byte, pub *rsa.PublicKey) error {
enc, err := encryptPassword(mc.cfg.Passwd, seed, pub)
if err != nil {
return err
}
return mc.writeAuthSwitchPacket(enc, false)
}
func (mc *mysqlConn) auth(authData []byte, plugin string) ([]byte, bool, error) {
switch plugin {
case "caching_sha2_password":
authResp := scrambleSHA256Password(authData, mc.cfg.Passwd)
return authResp, false, nil
case "mysql_old_password":
if !mc.cfg.AllowOldPasswords {
return nil, false, ErrOldPassword
}
// Note: there are edge cases where this should work but doesn't;
// this is currently "wontfix":
// https://github.com/go-sql-driver/mysql/issues/184
authResp := scrambleOldPassword(authData[:8], mc.cfg.Passwd)
return authResp, true, nil
case "mysql_clear_password":
if !mc.cfg.AllowCleartextPasswords {
return nil, false, ErrCleartextPassword
}
// http://dev.mysql.com/doc/refman/5.7/en/cleartext-authentication-plugin.html
// http://dev.mysql.com/doc/refman/5.7/en/pam-authentication-plugin.html
return []byte(mc.cfg.Passwd), true, nil
case "mysql_native_password":
if !mc.cfg.AllowNativePasswords {
return nil, false, ErrNativePassword
}
// https://dev.mysql.com/doc/internals/en/secure-password-authentication.html
// Native password authentication only need and will need 20-byte challenge.
authResp := scramblePassword(authData[:20], mc.cfg.Passwd)
return authResp, false, nil
case "sha256_password":
if len(mc.cfg.Passwd) == 0 {
return nil, true, nil
}
if mc.cfg.tls != nil || mc.cfg.Net == "unix" {
// write cleartext auth packet
return []byte(mc.cfg.Passwd), true, nil
}
pubKey := mc.cfg.pubKey
if pubKey == nil {
// request public key from server
return []byte{1}, false, nil
}
// encrypted password
enc, err := encryptPassword(mc.cfg.Passwd, authData, pubKey)
return enc, false, err
default:
errLog.Print("unknown auth plugin:", plugin)
return nil, false, ErrUnknownPlugin
}
}
func (mc *mysqlConn) handleAuthResult(oldAuthData []byte, plugin string) error {
// Read Result Packet
authData, newPlugin, err := mc.readAuthResult()
if err != nil {
return err
}
// handle auth plugin switch, if requested
if newPlugin != "" {
// If CLIENT_PLUGIN_AUTH capability is not supported, no new cipher is
// sent and we have to keep using the cipher sent in the init packet.
if authData == nil {
authData = oldAuthData
} else {
// copy data from read buffer to owned slice
copy(oldAuthData, authData)
}
plugin = newPlugin
authResp, addNUL, err := mc.auth(authData, plugin)
if err != nil {
return err
}
if err = mc.writeAuthSwitchPacket(authResp, addNUL); err != nil {
return err
}
// Read Result Packet
authData, newPlugin, err = mc.readAuthResult()
if err != nil {
return err
}
// Do not allow to change the auth plugin more than once
if newPlugin != "" {
return ErrMalformPkt
}
}
switch plugin {
// https://insidemysql.com/preparing-your-community-connector-for-mysql-8-part-2-sha256/
case "caching_sha2_password":
switch len(authData) {
case 0:
return nil // auth successful
case 1:
switch authData[0] {
case cachingSha2PasswordFastAuthSuccess:
if err = mc.readResultOK(); err == nil {
return nil // auth successful
}
case cachingSha2PasswordPerformFullAuthentication:
if mc.cfg.tls != nil || mc.cfg.Net == "unix" {
// write cleartext auth packet
err = mc.writeAuthSwitchPacket([]byte(mc.cfg.Passwd), true)
if err != nil {
return err
}
} else {
pubKey := mc.cfg.pubKey
if pubKey == nil {
// request public key from server
data := mc.buf.takeSmallBuffer(4 + 1)
data[4] = cachingSha2PasswordRequestPublicKey
mc.writePacket(data)
// parse public key
data, err := mc.readPacket()
if err != nil {
return err
}
block, _ := pem.Decode(data[1:])
pkix, err := x509.ParsePKIXPublicKey(block.Bytes)
if err != nil {
return err
}
pubKey = pkix.(*rsa.PublicKey)
}
// send encrypted password
err = mc.sendEncryptedPassword(oldAuthData, pubKey)
if err != nil {
return err
}
}
return mc.readResultOK()
default:
return ErrMalformPkt
}
default:
return ErrMalformPkt
}
case "sha256_password":
switch len(authData) {
case 0:
return nil // auth successful
default:
block, _ := pem.Decode(authData)
pub, err := x509.ParsePKIXPublicKey(block.Bytes)
if err != nil {
return err
}
// send encrypted password
err = mc.sendEncryptedPassword(oldAuthData, pub.(*rsa.PublicKey))
if err != nil {
return err
}
return mc.readResultOK()
}
default:
return nil // auth successful
}
return err
}
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