搭建私有CA服务器

2016/05/11 https

搭建私有CA服务器

CA是什么

CA(Certificate Authority)证书颁发机构主要负责证书的颁发、管理以及归档和吊销。证书内包含了拥有证书者的姓名、地址、电子邮件帐号、公钥、证书有效期、发放证书的CA、CA的数字签名等信息。证书主要有三大功能:加密、签名、身份验证。

centos6.x上有关ssl证书的目录结构如下:

/etc/pki/CA/
├── certs
├── crl      吊销的证书
├── newcerts 存放CA签署(颁发)过的数字证书(证书备份目录)
└── private  用于存放CA的私钥

/etc/pki/tls/
├── cert.pem -> certs/ca-bundle.crt   软链接到certs/ca-bundle.crt
├── certs     该服务器上的证书存放目录,可以放置自己的证书和内置证书
│   ├── ca-bundle.crt 内置信任的证书
│   ├── ca-bundle.trust.crt
│   ├── make-dummy-cert
│   └── Makefile
├── misc
│   ├── CA
│   ├── c_hash
│   ├── c_info
│   ├── c_issuer
│   └── c_name
├── openssl.cnf openssl的CA主配置文件
└── private   证书密钥存放目录

CA要给别人颁发证书,首先自己得有一个作为根证书,我们得在一切工作之前修改好CA的配置文件、序列号、索引等等。

vi /etc/pki/tls/openssl.cnf

一.建立CA服务器

1.生成根密钥

为了安全起见,修改cakey.pem私钥文件权限为600或400,也可以使用子shell生成( umask 077; openssl genrsa -out private/cakey.pem 2048 ),下面不再重复。

cd /etc/pki/CA/
openssl genrsa -out private/cakey.pem 2048
或使用命令
( umask 077; openssl genrsa -out /etc/pki/CA/private/cakey.pem 2048 )

执行结果如下:

[root@localhost CA]# ( umask 077; openssl genrsa -out /etc/pki/CA/private/cakey.pem 2048 )
Generating RSA private key, 2048 bit long modulus
..................+++
...+++
e is 65537 (0x10001)

参数说明:

    ():表示此命令在子进程中运行,其目的是为了不改变当前Shell中的umask值;
    genrsa:生成私钥;
    -out:私钥的存放路径,cakey.pem:为密钥名,与配置文件中保持一致;
    2048:密钥长度,默认为1024。

2.生成根证书

使用req命令生成自签证书:会提示输入一些内容,因为是私有的,所以可以随便输入(之前修改的openssl.cnf会在这里呈现),最好记住能与后面保持一致 自签证书cacert.pem应该生成在/etc/pki/CA下。

openssl req -new -x509 -key /etc/pki/CA/private/cakey.pem -out cacert.pem -days 3650

执行结果如下:

[root@localhost CA]# openssl req -new -x509 -key /etc/pki/CA/private/cakey.pem -out /etc/pki/CA/cacert.pem -days 3650
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:beijing
Locality Name (eg, city) [Default City]:beijing
Organization Name (eg, company) [Default Company Ltd]:home
Organizational Unit Name (eg, section) []:homepart
Common Name (eg, your name or your server's hostname) []:home.home
Email Address []:home@home.home

参数说明:

    req:生成证书签署请求;
    -x509:生成自签署证书;
    -days n:证书的有效天数;
    -new:新请求;
    -key /path/to/keyfile:指定私钥文件;
    -out /path/to/somefile:输出文件位置。

3.初始化工作环境

touch /etc/pki/CA/index.txt /etc/pki/CA/serial   创建index.txt,serial文件
echo 01 > /etc/pki/CA/serial
mkdir -p /etc/pki/CA/csr/ 用来存放节点上传过来的csr证书请求目录

index.txt:索引文件,用于匹配证书编号; serial:证书序列号文件,只在首次生成证书时赋值。

二.节点生成证书

以上都是在CA服务器上做的操作,而且只需进行一次,现在转到nginx服务器上执行:

1.生成密钥对:

为我们的nginx web服务器生成ssl密钥

mkdir -p /etc/nginx/ssl
cd /etc/nginx/ssl
(umask 077; openssl genrsa -out /etc/nginx/ssl/nginx.key 2048) 生成私钥

执行结果:

[root@localhost ssl]# (umask 077; openssl genrsa -out /etc/nginx/ssl/nginx.key 2048)
Generating RSA private key, 2048 bit long modulus
..................+++
.................+++
e is 65537 (0x10001)

2.生成证书请求:

为nginx生成证书签署请求

openssl req -new -key /etc/nginx/ssl/nginx.key  -out /etc/nginx/ssl/nginx.csr

同样会提示输入一些内容,其它随便,除了Commone Name一定要是你要授予证书的服务器域名或主机名,challenge password不填。

执行结果如下:

[root@localhost ssl]# openssl req -new -key /etc/nginx/ssl/nginx.key  -out /etc/nginx/ssl/nginx.csr
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:CN
State or Province Name (full name) []:shanghai
Locality Name (eg, city) [Default City]:shanghai
Organization Name (eg, company) [Default Company Ltd]:mycompany
Organizational Unit Name (eg, section) []:tech
Common Name (eg, your name or your server's hostname) []:myweb.com
Email Address []:myweb@myweb.com

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:

3.把签署请求文件发送给CA服务器

接下来要把上一步生成的证书请求csr文件,发到CA服务器上(其中192.168.1.80为CA服务器)

scp /etc/nginx/ssl/nginx.csr 192.168.1.80:/etc/pki/CA/csr/nginx.csr
测试时节点和CA服务器是同一台,故使用如下命令
cp /etc/nginx/ssl/nginx.csr /etc/pki/CA/csr/nginx.csr

三.签署证书

1.在CA服务器上签署证书

私有CA根据请求来签署证书,在CA服务器上执行

openssl ca -in /etc/pki/CA/csr/nginx.csr  -out /etc/pki/CA/nginx.crt -days 3650

另外在极少数情况下,上面的命令生成的证书不能识别,试试下面的命令:
# openssl x509 -req -in /etc/pki/CA/csr/nginx.csr -CA /etc/pki/CA/cacert.pem -CAkey /etc/pki/CA/private/cakey.pem -CAcreateserial -out /etc/pki/CA/nginx2.crt

这里出错了,由于根证书是beijing而节点是shanghai

[root@localhost CA]# openssl ca -in /etc/pki/CA/csr/nginx.csr  -out /etc/pki/CA/nginx.crt -days 3650
Using configuration from /etc/pki/tls/openssl.cnf
Check that the request matches the signature
Signature ok
The stateOrProvinceName field needed to be the same in the
CA certificate (beijing) and the request (shanghai)

重新生成节点csr证书请求,设置区域为beijing 执行结果如下(成功):

[root@localhost CA]# openssl ca -in /etc/pki/CA/csr/nginx.csr  -out /etc/pki/CA/nginx.crt -days 3650                                                        Using configuration from /etc/pki/tls/openssl.cnf
Check that the request matches the signature
Signature ok
Certificate Details:
        Serial Number: 1 (0x1)
        Validity
            Not Before: Jun  2 10:21:22 2017 GMT
            Not After : May 31 10:21:22 2027 GMT
        Subject:
            countryName               = CN
            stateOrProvinceName       = beijing
            organizationName          = home
            organizationalUnitName    = home
            commonName                = *.test.com
            emailAddress              = my@test.com
        X509v3 extensions:
            X509v3 Basic Constraints: 
                CA:FALSE
            Netscape Comment: 
                OpenSSL Generated Certificate
            X509v3 Subject Key Identifier: 
                96:D7:60:53:1E:52:3E:89:4F:A0:A4:3D:81:CA:97:D5:D8:67:AE:93
            X509v3 Authority Key Identifier: 
                keyid:D5:71:B2:72:16:62:03:09:BB:6D:B2:14:5F:F2:3C:B5:AE:C1:BD:08

Certificate is to be certified until May 31 10:21:22 2027 GMT (3650 days)
Sign the certificate? [y/n]:y


1 out of 1 certificate requests certified, commit? [y/n]y
Write out database with 1 new entries
Data Base Updated

上面签发过程其实默认使用了-cert cacert.pem -keyfile cakey.pem,这两个文件就是前两步生成的位于/etc/pki/CA下的根密钥和根证书。

2.将crt证书发送给请求者

将生成的crt证书发回nginx服务器使用。192.168.137.61为nginx服务器地址

scp /etc/pki/CA/csr/nginx.crt  192.168.137.61:/etc/nginx/ssl/
同一台本机使用
cp /etc/pki/CA/nginx.crt /etc/nginx/ssl/

到此我们已经拥有了建立ssl安全连接所需要的所有文件,并且服务器的crt和key都位于配置的目录下,剩下的是如何使用证书的问题。

四.吊销证书

1.节点请求吊销

[root@localhost CA]#  openssl x509 -in /etc/nginx/ssl/nginx.crt  -noout -serial -subject         
serial=01
subject= /C=CN/ST=beijing/O=home/OU=home/CN=*.test.com/emailAddress=my@test.com

参数说明:

x509:证书格式
-in:要吊销的证书
-noout:不输出额外信息
-serial:显示序列号
-subject:显示subject信息

2.CA验证信息

2.1 节点提交的serial和subject信息来验证与index.txt文件中的信息是否一致

[root@localhost CA]# cat /etc/pki/CA/index.txt
V       270531102122Z           01      unknown /C=CN/ST=beijing/O=home/OU=home/CN=*.17coolz.com/emailAddress=my@test.com

2.2 吊销证书

openssl ca -revoke /etc/pki/CA/newcerts/01.pem

参数说明 -revoke:删除证书。 执行结果

[root@localhost CA]# openssl ca -revoke /etc/pki/CA/newcerts/01.pem
Using configuration from /etc/pki/tls/openssl.cnf
Revoking Certificate 01.
Data Base Updated

2.3 查看被吊销的证书列表

[root@localhost CA]# cat /etc/pki/CA/index.txt
R       270531102122Z   170602103652Z   01      unknown /C=CN/ST=beijing/O=home/OU=home/CN=*.17coolz.com/emailAddress=my@test.com

2.4 生成吊销证书的编号(如果是第一次吊销)

echo 00 > /etc/pki/CA/crlnumber

2.5 更新证书吊销列表

openssl ca -gencrl -out /etc/pki/CA/crl/ca.crl

执行结果:

[root@localhost CA]# openssl ca -gencrl -out /etc/pki/CA/crl/ca.crl
Using configuration from /etc/pki/tls/openssl.cnf

2.6 查看吊消crl文件内容

openssl crl -in crl/ca.crl -noout -text

执行结果

[root@localhost CA]# openssl crl -in /etc/pki/CA/crl/ca.crl -noout -text
Certificate Revocation List (CRL):
        Version 2 (0x1)
    Signature Algorithm: sha1WithRSAEncryption
        Issuer: /C=CN/ST=beijing/L=beijing/O=home/OU=homepart/CN=home.home/emailAddress=home@home.home
        Last Update: Jun  2 10:41:24 2017 GMT
        Next Update: Jul  2 10:41:24 2017 GMT
        CRL extensions:
            X509v3 CRL Number: 
                0
Revoked Certificates:
    Serial Number: 01
        Revocation Date: Jun  2 10:36:52 2017 GMT
    Signature Algorithm: sha1WithRSAEncryption
         a3:fc:cf:fd:08:44:d9:c0:fd:78:75:5f:79:3a:c3:16:17:da:
         b8:b1:cc:d8:67:28:73:75:4a:e1:11:e3:04:de:0a:36:4f:d6:
         de:ec:37:3b:0b:18:0f:24:18:d1:8b:c9:6a:f8:e0:d3:c6:cc:
         42:67:5b:15:34:da:f9:49:eb:19:73:33:4e:ef:eb:cb:82:12:
         4c:27:ee:5e:9d:50:5f:8b:0c:51:3a:05:e3:0f:fb:3c:0d:0b:
         8e:af:17:5e:b2:7d:30:af:e6:60:f2:6e:7f:b5:b5:9b:b1:f7:
         5e:d4:80:73:d3:cc:30:e1:78:71:db:81:a0:ad:49:6a:dc:5c:
         12:bf:31:0f:11:59:54:80:e9:74:36:f7:98:e2:86:f2:29:3f:
         b0:69:b8:a4:32:9d:1c:61:01:ed:0f:09:b0:10:be:f4:07:ac:
         32:91:9c:cc:35:cf:c3:cb:44:6b:86:22:81:7d:7a:71:9d:5c:
         34:da:30:47:5a:ce:0f:10:bc:2a:56:8f:41:85:de:95:48:5c:
         d3:b2:90:ae:4f:7e:7c:d1:53:5c:6f:67:cb:aa:cc:78:5b:1a:
         f6:31:5b:7e:04:03:73:da:6e:8d:00:d7:bf:db:75:6a:0e:44:
         be:c1:20:0f:72:40:4c:29:fc:aa:87:30:9e:84:55:e1:76:a2:
         00:05:39:18

参数说明

-text:以文本形式显示。

后话

如果你要自己做CA,别忘了客户端需要导入CA的证书(CA的证书是自签名的,导入它意味着你“信任”这个CA签署的证书)。而商业CA的一般不用,因为它们已经内置在你的浏览器中了。

参考:

http://www.178linux.com/12742
http://www.cnblogs.com/zhaojiedi1992/p/zhaojiedi_linux_011_ca.html
http://seanlook.com/2015/01/18/openssl-self-sign-ca/

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