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：

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

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