作者：俊达
引言
MySQL支持使用TLS协议进行通信，该协议在数据库通信中具有关键作用。首先，TLS能够加密客户端与服务端之间的通信数据，涵盖了客户端发送至服务端的SQL请求以及服务端返回给客户端的数据，从而确保敏感信息的保密性和完整性。除此之外，TLS还允许客户端验证服务端的身份，确保安全连接。同时，TLS还使得服务端能够验证客户端的身份，实现双向认证，从而进一步增强了通信安全性和互信性。这些TLS功能在MySQL通信中发挥着重要作用，为数据传输提供了必要的保护和验证机制。
1 Server端开启SSL
服务端默认已经开启SSL，可以通过如下命令查看是否支持SSL：
参数have_ssl为 YES
| have_openssl | YES |
| have_ssl | YES |
| ssl_ca | ca.pem |
| ssl_capath | |
| ssl_cert | server-cert.pem |
| ssl_cipher | |
| ssl_crl | |
| ssl_crlpath | |
| ssl_key | server-key.pem |
参数说明：
| 参数 | 说明 |
|---|---|
| have_openssl | 和have_ssl一样 |
| have_ssl | YES: 启用SSL |
| DISABLED: 已经编译了SSL功能，但是没有开启 | |
| ssl_ca | CA文件，默认是ca.pem |
| ssl_capath | CA文件路径，默认为空。mysqld会从datadir查找ca.pem |
| ssl_cert | 服务端证书，默认server-cert.pem. |
| ssl_cipher | SSL加密方式，默认为空 |
| ssl_crl | certificate revocation lists文件，默认为空 |
| ssl_crlpath | certificate revocation lists文件路径，默认为空 |
| ssl_key | 服务端证书私钥，默认server-key.pem. |
server端启用SSL，需要ca.pem, server-cert.pem, server-key.pem 3个文件。
客户端需要有ca.pem, client-cert.pem, client-key.pem 3个文件。
2 客户端SSL
使用mysql客户端连接到服务端时，默认会使用加密通信，
登陆后输入 \s, 或者show status like 'ssl_cipher'，如果看Cipher信息，说明连接已经开启加密通信
[root@box1 mysql]# mysql -uroot -h127.0.0.1 -P3306 -phello
Server version: 5.7.32 MySQL Community Server (GPL)
...
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> \s
--------------
mysql Ver 14.14 Distrib 5.7.32, for Linux (x86_64) using EditLine wrapper
Connection id: 23
Current database:
Current user: root@localhost
SSL: Cipher in use is ECDHE-RSA-AES128-GCM-SHA256
Current pager: stdout
Using outfile: ''
Using delimiter: ;
Server version: 5.7.32 MySQL Community Server (GPL)
Protocol version: 10
Connection: 127.0.0.1 via TCP/IP
Server characterset: latin1
mysql> show status like 'ssl_cipher';
+---------------+-----------------------------+
| Variable_name | Value |
+---------------+-----------------------------+
| Ssl_cipher | ECDHE-RSA-AES128-GCM-SHA256 |
2.1 客户端禁用ssl通信
mysql客户端登陆时加上 --ssl-mode=disabled禁用TLS通信
mysql -uroot -h127.0.0.1 -P3306 -phello --ssl-mode=disabled
mysql> \s
--------------
mysql Ver 14.14 Distrib 5.7.32, for Linux (x86_64) using EditLine wrapper
Connection id: 25
Current database:
Current user: root@localhost
SSL: Not in use
Current pager: stdout
mysql> show status like 'ssl_cipher';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| Ssl_cipher | |
+---------------+-------+
2.2客户端要求验证服务端证书
客户端可以要求验证服务端的证书。
mysql客户端将ssl-mode参数设置为verify_ca或verify_identity, 同时需要提供用来签名的ca证书。
verify_ca的作用，是为了让服务端证明，他的证书是客户端参数中的指定的ca签名的。其他服务器无法冒充。
mysql -uroot -h127.0.0.1 -P3306 -phello --ssl-mode=verify_ca --ssl-ca=ca.pem
show status like 'ssl_cipher';
+---------------+-----------------------------+
| Variable_name | Value |
+---------------+-----------------------------+
| Ssl_cipher | ECDHE-RSA-AES128-GCM-SHA256 |
如果证书验证不通过，客户端连接会报错。服务端日志中也能看到相关报错信息。
### client
root@box1 mysql]# mysql -uroot -h127.0.0.1 -P3306 -phello --ssl-mode=verify_ca --ssl-ca=/data/mysql01/data/ca.pem
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 2026 (HY000): SSL connection error: error:00000001:lib(0):func(0):reason(1)
### server
[root@box1 mysql]# tail -1 /var/log/mysqld.log
2021-03-31T23:34:20.461350Z 28 [Note] Bad handshake
3 服务端要求验证客户端使用SSL登录
虽然服务端开启了SSL，但是默认情况下用户可以选择启用或不启用加密通信。
服务端可以强制要求客户端使用加密通信，也可以要求客户端证明自己的身份。
这可以在创建用户的时候指定。
CREATE USER 'user_1'@'%' identified by 'hello' require ssl;
CREATE USER 'user_2'@'%' identified by 'hello' require x509;
CREATE USER 'user_3'@'%' identified by 'hello' require cipher 'ECDHE-RSA-AES256-GCM-SHA384';
CREATE USER 'user_4'@'%' identified by 'hello' require cipher 'ECDHE-ECDSA-AES256-GCM-SHA384';
CREATE USER 'user_5'@'%' identified by 'hello' require issuer 'www.dtstack.com' ;
CREATE USER 'user_6'@'%' identified by 'hello' require subject '/CN=client.dtstack.com';
上面创建的用户中，
user_1必须开启SSL加密才能连接到服务器
user_2需要使用x509证书格式
user_3需要使用cipher ECDHE-RSA-AES256-GCM-SHA384
user_4需要使用cipher ECDHE-ECDSA-AES256-GCM-SHA384
user_5需要使用www.dtstack.com签发的证书
user_6需要使用subject为client.dtstack.com的证书
4测试用户信息
select user,host, ssl_type, ssl_cipher, x509_issuer, x509_subject from mysql.user where user like 'user%';
+--------+------+-----------+-------------------------------+-----------------+------------------------+
| user | host | ssl_type | ssl_cipher | x509_issuer | x509_subject |
+--------+------+-----------+-------------------------------+-----------------+------------------------+
| user_1 | % | ANY | | | |
| user_2 | % | X509 | | | |
| user_3 | % | SPECIFIED | ECDHE-RSA-AES256-GCM-SHA384 | | |
| user_4 | % | SPECIFIED | ECDHE-ECDSA-AES256-GCM-SHA384 | | |
| user_5 | % | SPECIFIED | | www.dtstack.com | client.dtstack.com |
| user_6 | % | SPECIFIED | | | /CN=client.dtstack.com |
+--------+------+-----------+-------------------------------+-----------------+------------------------+
4.1强制SSL
user_1登陆，如果不开启ssl-mode，登陆报错。使用SSL才能登陆
[root@box1 pki]# mysql -uuser_1 -phello -h127.0.0.1 --ssl-mode=disabled
mysql: [Warning] Using a password on the command line interface can be insecure.
ERROR 1045 (28000): Access denied for user 'user_1'@'localhost' (using password: YES)
[root@box1 pki]# mysql -uuser_1 -phello -h127.0.0.1
...
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> \s
...
Current user: user_1@localhost
SSL: Cipher in use is ECDHE-RSA-AES128-GCM-SHA256
4.2强制使用客户端证书
user_2需要x509证书才能登陆
[root@box1 pki]# mysql -uuser_2 -phello -h127.0.0.1
ERROR 1045 (28000): Access denied for user 'user_2'@'localhost' (using password: YES)
[root@box1 pki]# mysql -uuser_2 -phello -h127.0.0.1 --ssl-mode=required
ERROR 1045 (28000): Access denied for user 'user_2'@'localhost' (using password: YES)
[root@box1 pki]# mysql -uuser_2 -phello -h127.0.0.1 --ssl-cert=client-cert.pem --ssl-key=client-key.pem
...
Welcome to the MySQL monitor. Commands end with ; or \g.
mysql> \s
...
Current user: user_2@localhost
SSL: Cipher in use is ECDHE-RSA-AES128-GCM-SHA256
4.3 强制指定客户端cipher
user_3指定了cipher, 无法登陆。 可以从服务端alert.log查看登陆失败的原因。
[root@box1 pki]# mysql -uuser_3 -pxhello -h127.0.0.1 --ssl-mode=required --ssl-cert=client-cert.pem --ssl-key=client-key.pem
ERROR 1045 (28000): Access denied for user 'user_3'@'localhost' (using password: YES)
### 服务端日志
[root@box1 mysql]# tail -1 /var/log/mysqld.log2021-04-01T00:07:44.216859Z 51 [Note] X509 ciphers mismatch: should be 'ECDHE-RSA-AES256-GCM-SHA384' but is 'ECDHE-RSA-AES128-GCM-SHA256'
2021-04-01T00:07:44.216915Z 51 [Note] Access denied for user 'user_3'@'localhost' (using password: YES)
说明了cipher不满足要求。
my.cnf增加ssl_ciphper参数，重启服务
[root@box1 mysql]# tail -1 /etc/my.cnf
ssl_cipher=ECDHE-RSA-AES256-GCM-SHA384
[root@box1 mysql]# service mysqld restart
Redirecting to /bin/systemctl restart mysqld.service
-- 再次尝试登陆，可以看到SSL 使用的ciper变成了 ECDHE-RSA-AES256-GCM-SHA384
[root@box1 pki]# mysql -uuser_3 -phello -h127.0.0.1 --ssl-mode=required --ssl-cert=client-cert.pem --ssl-key=client-key.pem
...
mysql> \s
Current user: user_3@localhost
SSL: Cipher in use is ECDHE-RSA-AES256-GCM-SHA384
4.4验证客户端证书的subject 和 issuer
### client
[root@box1 pki]# mysql -uuser_5 -phello -h127.0.0.1 --ssl-mode=required --ssl-cert=client-cert.pem --ssl-key=client-key.pem
ERROR 1045 (28000): Access denied for user 'user_5'@'localhost' (using password: YES)
### server
[root@box1 mysql]# tail -2 /var/log/mysqld.log
2021-04-01T01:17:21.692560Z 6 [Note] X509 issuer mismatch: should be 'www.dtstack.com' but is '/C=CN/ST=HZ/L=ZJ/O=lazybug CO/OU=freecity/CN=www.dtstack.com/emailAddress=junda@dtstack.com'
2021-04-01T01:17:21.692607Z 6 [Note] Access denied for user 'user_5'@'localhost' (using password: YES)
### client
[root@box1 pki]# mysql -uuser_6 -phello -h127.0.0.1 --ssl-mode=required --ssl-cert=client-cert.pem --ssl-key=client-key.pem
ERROR 1045 (28000): Access denied for user 'user_6'@'localhost' (using password: YES)
### server
[root@box1 mysql]# tail -2 /var/log/mysqld.log
2021-04-01T01:20:41.297093Z 8 [Note] X509 subject mismatch: should be '/CN=client.dtstack.com' but is '/C=XX/L=Default City/O=Default Company Ltd'
2021-04-01T01:20:41.297144Z 8 [Note] Access denied for user 'user_6'@'localhost' (using password: YES)
重新生成client证书，指定subject
[root@box1 pki]# openssl req -subj /CN=client.dtstack.com -newkey rsa:2048 -days 3600 \
-nodes -keyout client-key.pem -out client-req.pem
writing new private key to 'client-key.pem'
[root@box1 pki]# openssl rsa -in client-key.pem -out client-key.pem
writing RSA key
[root@box1 pki]# openssl x509 -sha384 -req -in client-req.pem -days 3600 \
> -CA ca.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem
Signature ok
subject=/CN=client.dtstack.com
Getting CA Private Key
使用新的证书，就可以登录的数据库了：
[root@box1 pki]# mysql -uuser_6 -phello -h127.0.0.1 --ssl-mode=required --ssl-cert=client-cert.pem --ssl-key=client-key.pem
...
mysql> \s
Current user: user_6@localhost
SSL: Cipher in use is ECDHE-RSA-AES256-GCM-SHA384
附录：SSL证书相关命令
生成证书的命令
# Create clean environment
rm -rf newcerts
mkdir newcerts && cd newcerts
# Create CA certificate
openssl genrsa 2048 > ca-key.pem
openssl req -new -x509 -nodes -days 3600 \
-key ca-key.pem -out ca.pem
# Create server certificate, remove passphrase, and sign it
# server-cert.pem = public key, server-key.pem = private key
openssl req -newkey rsa:2048 -days 3600 \
-nodes -keyout server-key.pem -out server-req.pem
openssl rsa -in server-key.pem -out server-key.pem
openssl x509 -sha384 -req -in server-req.pem -days 3600 \
-CA ca.pem -CAkey ca-key.pem -set_serial 01 -out server-cert.pem
# Create client certificate, remove passphrase, and sign it
# client-cert.pem = public key, client-key.pem = private key
openssl req -subj /client.dtstack.com -newkey rsa:2048 -days 3600 \
-nodes -keyout client-key.pem -out client-req.pem
openssl rsa -in client-key.pem -out client-key.pem
openssl x509 -sha384 -req -in client-req.pem -days 3600 \
-CA ca.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem
openssl x509 -req -in client-req.pem -days 3600 \
-CA ca.pem -CAkey ca-key.pem -set_serial 01 -out client-cert.pem
查看证书信息
[root@box1 mysql]# openssl x509 -text -in server-cert.pem -noout
Certificate:
Data:
Version: 3 (0x2)
Serial Number: 2 (0x2)
Signature Algorithm: sha256WithRSAEncryption
Issuer: CN=MySQL_Server_5.7.32_Auto_Generated_CA_Certificate
Validity
Not Before: Mar 31 12:14:46 2021 GMT
Not After : Mar 29 12:14:46 2031 GMT
Subject: CN=MySQL_Server_5.7.32_Auto_Generated_Server_Certificate
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 bit)
Modulus:
[root@box1 pki]# openssl x509 -text -in client-cert.pem -noout
Certificate:
Data:
Version: 1 (0x0)
Serial Number: 1 (0x1)
Signature Algorithm: sha384WithRSAEncryption
Issuer: C=CN, ST=HZ, L=ZJ, O=lazybug CO, OU=freecity, CN=www.dtstack.com/emailAddress=junda@dtstack.com
Validity
Not Before: Apr 1 01:34:53 2021 GMT
Not After : Feb 8 01:34:53 2031 GMT
Subject: CN=client.dtstack.com
Subject Public Key Info:
Public Key Algorithm: rsaEncryption
Public-Key: (2048 b
验证证书
使用openssl verify命令验证证书有效性。CAfile是用于创建证书的ca文件。
[root@box1 pki]# openssl verify -CAfile ca.pem server-cert.pem client-cert.pem
server-cert.pem: OK
client-cert.pem: OK
如果ca文件和证书文件不匹配，验证会报错
[root@box1 pki]# openssl verify -CAfile /var/lib/backupca/ca.pem server-cert.pem client-cert.pem
server-cert.pem: C = CN, ST = ZJ, L = HZ, O = bugfree server, OU = land, CN = www.dtstack.com, emailAddress = server@dtstack.com
error 20 at 0 depth lookup:unable to get local issuer certificate
client-cert.pem: CN = client.dtstack.com
error 20 at 0 depth lookup:unable to get local issuer certificate