搭建私有CA

一、实验目的

搭建私有CA并使其可以实现公司内部的的签名服务。

二、实验环境：

系统架构：Centos7（服务器）、Centos6（需要申请证书的服务器）
需要的软件包：openssl、openssl-libs、libssl

三、配置文件解析

搭建CA需要/etc/pki/tls/openssl.cnf文件，该配置文件 由openssl-libs生成

该配置文件中我们主要关注一下这些选项，我只列出了需要关注的，源配置文件不关注的不要修改

[ ca ]
default_ca      = CA_default            这里代表默认的ca 策略
[ CA_default ]
dir             = /etc/pki/CA           定义CA的目录
    certs           = $dir/certs            定义证书的存放位置$dir表示上一个选项dir，之后的也是同样的意思
crl_dir         = $dir/crl              定义吊销证书的目录
database        = $dir/index.txt        证书数据库文件，注意：默认这个文件是不存在的需要手动创建，如果不创建，在签名证书时会报错
new_certs_dir   = $dir/newcerts         新证书的存放位置，每次签发证书之后都会在这个目录和$dir/certs目录生成同样的证书，但是这里是以编号命名的
certificate     = $dir/cacert.pem       自签或上级颁发的证书存放位置，注意：这里是自己的证书
serial          = $dir/serial           存放证书编号的位置，注意：默认这个文件不存在，需要手动创建，且需要初始化一个16进制的序号，我们一般都使用00作为初始化的默认值
crlnumber       = $dir/crlnumber        存放吊销证书编号的目录，注意是编号
crl             = $dir/crl.pem          吊销的证书
private_key     = $dir/private/cakey.pem自己的私有秘钥
RANDFILE        = $dir/private/.rand    自己的随机数文件，这个默认不需要改
x509_extensions = usr_cert              # The extentions to add to the cert
default_days    = 365                   # 默认的证书有效期
default_crl_days= 30                    # 默认多少天发布一次crl（吊销）
default_md      = sha256                # 使用默认的单项加密算法
policy          = policy_match          # 策略，这里是一个映射，映射的是“[ policy_match ]”
[ policy_match ]                        #默认的申请ca的策略
countryName             = match         #国家
stateOrProvinceName     = match         #州或省
organizationName        = match         #组织名称
organizationalUnitName  = optional      #组织的名称
commonName              = supplied      #域名
emailAddress            = optional      #电子邮件
[ policy_anything ]                      #默认的申请ca的策略
countryName             = optional
stateOrProvinceName     = optional
localityName            = optional
organizationName        = optional
organizationalUnitName  = optional
commonName              = supplied
emailAddress            = optional

如果要更换policy的策略，可以自己写，也可以借助默认的修改一下即可

四、修改openssl.cnf文件

一般私有CA都是用在公司内部的，作为自己公司的证书服务器，所以policy我们使用系统默认的策略“policy_match”，即countryName、stateOrProvinceName 、organizationName 都是完全匹配的，因为，我们不需要为其他公司授权，所以权限放小一点。

default_days 我们修改证书有效期为20年     ： default_days = 7300

五、配置私有CA

配置CA的步骤如下：

1、生成自己的私钥文件
2、生成自签名证书

1、搭建CA

[root@newhostname tls]# (umask 066;openssl genrsa -out /etc/pki/CA/private/cakey.pem)
Generating RSA private key, 2048 bit long modulus
.................................................+++
.........................................................+++
e is 65537 (0x10001)

生成自己的私钥文件，注意：私钥文件必须保存在与配置文件标注的位置，且文件名必须相同

[root@newhostname tls]# openssl req -new -x509 -key /etc/pki/CA/private/cakey.pem -out /etc/pki/CA/certs/cacert.pem -days 7300
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]:zh
State or Province Name (full name) []:beijing
Locality Name (eg, city) [Default City]:beijing
Organization Name (eg, company) [Default Company Ltd]:xedj
Organizational Unit Name (eg, section) []:xedj
Common Name (eg, your name or your server's hostname) []:*.xedj.com
Email Address []:

req 表示请求，详细参数可以通过man req来查看；
-new表示生成一个新的证书
-key 指定加密要使用的私钥文件
-x509表示自签名
-days 表示证书的有效期，因为改过配置文件，所以不加这项默认也是20年
注意，输出位置必须是配置文件指定的位置指定的名字，否则后面会报错

2、现在我们查看一下我们生成的证书

[root@newhostname certs]# cat /etc/pki/CA/certs/cacert.pem
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
[root@newhostname certs]# 

证书经过私钥加过密，什么都看不出来，必须通过一下方式来查看

[root@newhostname certs]# openssl x509 -in /etc/pki/CA/certs/cacert.pem -noout -text
Certificate:
    Data:
        Version: 3 (0x2)
        Serial Number:
            ac:f8:01:78:f5:9e:c6:8d
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: C=zh, ST=beijing, L=beijing, O=xedj, OU=xedj, CN=*.xedj.com
        Validity
            Not Before: Jan  8 12:35:19 2018 GMT
            Not After : Jan  3 12:35:19 2038 GMT
        Subject: C=zh, ST=beijing, L=beijing, O=xedj, OU=xedj, CN=*.xedj.com
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:bd:52:f3:e5:99:7d:5d:5a:5c:cb:96:d6:bf:22:
                    eb:12:b7:d7:1f:e9:99:e2:12:41:1a:b5:ec:2c:5a:
                    4b:12:6d:da:7c:70:16:18:74:5c:fc:c4:b7:2a:11:
                    9a:e5:32:da:ff:5a:44:c7:45:64:3a:ad:ce:7f:f4:
                    c8:47:d9:33:36:dd:86:ea:dd:05:5d:03:78:b6:5c:
                    e8:93:20:33:23:8e:99:1f:72:78:c7:5e:03:a9:4d:
                    7c:1f:bd:61:5a:76:e3:06:bc:40:72:3c:ae:18:cb:
                    58:dd:f9:c5:b9:f1:85:31:a2:99:8f:87:d1:2d:3c:
                    18:e1:cf:0a:5e:7c:44:49:47:45:76:6e:37:c7:0a:
                    c1:fa:66:1e:fa:57:c9:f5:5b:0b:aa:4e:e1:4d:22:
                    a0:07:a7:c0:45:27:ee:4b:2d:75:ac:27:a3:d4:ba:
                    73:9a:64:a4:93:1a:ab:a3:dd:b3:16:52:66:b0:b9:
                    85:bd:7a:88:94:cb:75:3b:5c:c8:42:93:67:fd:75:
                    a1:35:82:3b:27:d0:d8:ad:5a:94:3d:06:9c:94:9f:
                    b0:24:f1:1c:41:23:be:ea:3f:bb:99:dd:2d:a8:a4:
                    65:fc:6a:e8:bc:5e:39:0e:26:88:57:ff:7c:d4:f0:
                    f5:74:d5:9b:22:80:b0:b9:03:3e:ce:1b:7d:e3:7b:
                    9d:8f
                Exponent: 65537 (0x10001)
        X509v3 extensions:
            X509v3 Subject Key Identifier:
                31:CA:40:4F:54:7B:76:6C:01:DF:F1:39:C7:8A:CA:2F:A2:4D:C0:9D
            X509v3 Authority Key Identifier:
                keyid:31:CA:40:4F:54:7B:76:6C:01:DF:F1:39:C7:8A:CA:2F:A2:4D:C0:9D

            X509v3 Basic Constraints:
                CA:TRUE
    Signature Algorithm: sha256WithRSAEncryption
         ae:ae:b0:88:56:6d:b0:24:8d:fe:b2:10:82:f9:5d:90:de:65:
         72:d2:21:ac:8b:58:17:3c:cb:02:2b:4a:ee:00:f3:3a:43:4f:
         90:9e:48:41:f4:48:75:92:8e:7b:98:9a:c0:eb:ca:d1:ed:13:
         ba:c6:d1:9f:63:af:48:b5:21:f0:9b:0b:1f:49:83:80:31:26:
         75:3c:b8:c9:2b:9b:34:39:53:d1:bf:eb:a6:67:47:57:2e:14:
         08:3c:24:b6:46:4a:30:bd:be:83:f3:13:90:53:aa:1e:df:f6:
         77:ec:05:8c:6a:0f:eb:e1:03:61:9a:26:69:60:ef:cd:ac:48:
         e0:14:54:df:c9:8c:84:d0:b7:8c:1f:25:62:e7:bf:8c:f9:b0:
         5a:72:68:47:37:f0:e2:09:52:f8:5a:1b:bd:43:e1:61:13:96:
         77:ec:10:a6:ee:6f:23:7b:3e:3c:92:d8:ae:f1:d6:8f:df:83:
         2e:0d:9d:12:24:70:0f:1b:f0:6d:10:11:3f:c1:96:32:2d:c0:
         b3:8b:6c:35:bf:b4:88:29:8a:da:75:96:0d:a3:fe:6f:e0:b6:
         76:18:48:bf:32:a9:aa:8a:4f:61:a6:69:78:4a:10:5f:ed:df:
         55:cd:e3:72:94:91:cc:fe:ea:a9:87:76:83:dd:e8:0c:25:6b:
         98:18:eb:1b
[root@newhostname certs]# 

x509是用来表示证书显示和签署实用程序
-noout用来消除编码的版本
-text使用它text的格式打印输出

通过上面的命令就可以查看我们刚才输入的证书的各种信息

[root@newhostname certs]# echo 01 >/etc/pki/CA/serial
[root@newhostname certs]# touch /etc/pki/CA/index.txt

前面第三节有注释这这个文件是做什么的，这里不再赘述

六、其他人通过搭建的私有CA申请证书

执行步骤：

1、预申请服务器生成自己的私钥
2、生成证书请求文件
3、将请求文件发送给私有CA
4、CA签名并返还生成的证书给请求者

[root@joker-6-01 ~]# (umaks 066;openssl genrsa -out /etc/pki/CA/private/zhang.pem 2048)
-bash: umaks: command not found
Generating RSA private key, 2048 bit long modulus
........................................................+++
......................+++
e is 65537 (0x10001)

生成私钥文件

[root@joker-6-01 ~]# openssl req -new -key /etc/pki/CA/private/zhang.pem  -out /etc/pki/CA/certs/zhang.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]:zh
State or Province Name (full name) []:beijing
Locality Name (eg, city) [Default City]:beijing
Organization Name (eg, company) [Default Company Ltd]:xedj
Organizational Unit Name (eg, section) []:xedj
Common Name (eg, your name or your server's hostname) []*.xedj.com               ^ Email Address []:

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

生成证书请求文件

现在我们查看一下这个请求文件

[root@joker-6-01 ~]# cat /etc/pki/CA/certs/zhang.csr
-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----

1总的来说生成证书请求文件与CA生成自签证书只差一个 -x509参数

下面将预申请服务器的请求文件发送到CA，用CA来签名

[root@joker-6-01 security]# scp /etc/pki/CA/certs/zhang.csr 172.18.30.253:~
root@172.18.30.253's password:
Permission denied, please try again.
root@172.18.30.253's password:
zhang.csr                                        100% 1001     1.0KB/s   00:00  

我们这里只是做实验，就使用scp来传输文件了

在CA服务器上生成自签证书的时候，我把目录搞错了；自签证书必须和配置文件一致，放对位置，现在把证书移到正确位置
mv /etc/pki/CA/certs/cacert.pem /etc/pki/CA/

下免在CA机器上做签名操作
[root@newhostname CA]# openssl ca -in ~/zhang.csr -out /etc/pki/CA/certs/zhang.crt  -days 365
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: Jan  8 15:48:14 2018 GMT
            Not After : Jan  8 15:48:14 2019 GMT
        Subject:
            countryName               = zh
            stateOrProvinceName       = beijing
            organizationName          = xedj
            organizationalUnitName    = xedj
            commonName                = *.xedj.com
        X509v3 extensions:
            X509v3 Basic Constraints:
                CA:FALSE
            Netscape Comment:
                OpenSSL Generated Certificate
            X509v3 Subject Key Identifier:
                FD:72:7A:F5:46:8C:69:C2:A2:74:3C:4C:0D:BF:6A:A1:84:70:C7:9F
            X509v3 Authority Key Identifier:
                keyid:31:CA:40:4F:54:7B:76:6C:01:DF:F1:39:C7:8A:CA:2F:A2:4D:C0:9D

Certificate is to be certified until Jan  8 15:48:14 2019 GMT (365 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

签名成功，现在可以签过名的证书返回给原服务器
[root@newhostname certs]# scp /etc/pki/CA/certs/zhang.crt 172.18.30.254:/etc/pki/CA/certs/
root@172.18.30.254's password:
zhang.crt                                                                                                  100% 4437     6.3MB/s   00:00 

查看数据库和现在的编号
[root@newhostname CA]# cat serial
02
[root@newhostname CA]# cat index.txt
V       190108154814Z           01      unknown /C=zh/ST=beijing/O=xedj/OU=xedj/CN=*.xedj.com
[root@newhostname CA]# echo 01 > /etc/pki/CA/crlnumber 初始化吊销证书序号

七、吊销证书

步骤：

1、查看要吊销证书的编号，确保不会吊销错
2、进行吊销操作

[root@newhostname CA]# cat index.txt
V       190108154814Z           01      unknown /C=zh/ST=beijing/O=xedj/OU=xedj/CN=*.xedj.com

查看数据库文件
第三列是证书序号即生成时serial序号，第五列是证书的主题，吊销时要确保主题是我们钥吊销的证书主题

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

吊销完成
-revoke 后面为serial序号命名的pem文件（这个具体也是根据配置文件来做的）

[root@newhostname CA]# openssl ca -gencrl -out /etc/pki/CA/crl.pem
Using configuration from /etc/pki/tls/openssl.cnf
 、
更新证书吊销列表

[root@newhostname CA]# openssl  crl -in /etc/pki/CA/crl.pem -noout -text

查看以吊销的证书

八、操作总结

1、(umask 066;openssl genrsa -out /etc/pki/CA/private/cakey.pem)       创建ca私钥
2、openssl req -new -x509 -key /etc/pki/CA/private/cakey.pem -out /etc/pki/CA/certs/cacert.pem -days 7300       生成CA的自签证书
3、openssl x509 -in /etc/pki/CA/certs/cacert.pem -noout -text     查看自签证书内容|
4、echo 01 >/etc/pki/CA/serial
touch /etc/pki/CA/index.txt           创建证书编号和数据库文件
5、(umaks 066;openssl genrsa -out /etc/pki/CA/private/zhang.pem 2048)      需要签名的服务器生成自己的私钥文件
6、openssl req -new -key /etc/pki/CA/private/zhang.pem -out /etc/pki/CA/certs/zhang.csr      通过私钥文件生成证书请求文件
7、openssl ca -in ~/zhang.csr -out /etc/pki/CA/certs/zhang.crt -days 365     将上一部生成的证书传送到CA服务器，并做签名操作
8、将做过签名证书返还给申请的服务器
9、cat index.txt    查看数据库文件
10、echo 01 > /etc/pki/CA/crlnumber 初始化吊销证书序号
11、openssl ca -revoke /etc/pki/CA/newcerts/01.pem         根据主题信息吊销需要吊销的证书|
12、openssl ca -gencrl -out /etc/pki/CA/crl.pem         更新吊销证书列表
13、openssl crl -in /etc/pki/CA/crl.pem -noout -text   查看吊销的证书