搭建私有CA服务器

1 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。

2 搭建CA服务器

2.1 配置文件查看

default_ca      = CA_default            # The default ca section                                          # ca的配置使用哪个片段。

####################################################################
[ CA_default ]

dir             = /etc/pki/CA           # Where everything is kept                                        # ca的主目录
certs           = $dir/certs            # Where the issued certs are kept                                 # 证书的保存位置
crl_dir         = $dir/crl              # Where the issued crl are kept
database        = $dir/index.txt        # database index file.                                            # 证书的索引文件
#unique_subject = no                    # Set to 'no' to allow creation of                                # 是否运行相同的subject信息的证书请求
                                        # several ctificates with same subject.
new_certs_dir   = $dir/newcerts         # default place for new certs.                                    # 最新的证书放置位置

certificate     = $dir/cacert.pem       # The CA certificate                                              # ca的自己给自己签发的证书（自签证书）
serial          = $dir/serial           # The current serial number                                       # 当前序列号
crlnumber       = $dir/crlnumber        # the current crl number
                                        # must be commented out to leave a V1 CRL
crl             = $dir/crl.pem          # The current CRL                                                 # 当前证书吊销列表
private_key     = $dir/private/cakey.pem# The private key                                                 # ca自己的私钥位置
RANDFILE        = $dir/private/.rand    # private random number file

x509_extensions = usr_cert              # The extentions to add to the cert

default_days    =                    # how long to certify for                                         # 默认颁发证书时间

policy          = policy_match                                                                            # 证书办法策略，这个片段下面就有

# For the CA policy
[ policy_match ]
countryName             = match                                                                           # match代表证书签发单位和证书请求单位的对应项目必须相同，其他的影响不大。
stateOrProvinceName     = match
organizationName        = match
organizationalUnitName  = optional
commonName              = supplied
emailAddress            = optional

countryName_default             = XX                                                                      # 默认国家，2为字母。下面还有其他的默认配置项目，比如默认省，默认市，默认公司等等。

2.2 生成秘钥

[root@localhost CA]# cd /etc/pki/CA/               #切换到CA目录
[root@localhost CA]# (umask ; openssl genrsa -out private/cakey.pem )  #调用openssl子命令genrsa生成私钥
Generating RSA private key,  bit long modulus
..+++
...................................................................................................................................................................................................................+++
e is  (0x10001)

注：上述命令使用（）扩着，表示在当前shell的子shell执行,()内的设定只在子shell内生效，每个命令使用“；”分割 ， umask指定掩码， -out选项指定了生成的私钥存放位置，不指定是输出到终端的。2048 指定秘钥的长度，默认是1024。

2.2 生成自签证书

[root@localhost CA]# openssl req -new -x509 -key private/cakey.pem -out cacert.pem -days
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 ( letter code) [GB]:CN
State or Province Name (full name) [Berkshire]:ZHENGZHOU
Locality Name (eg, city) [Newbury]:
[root@localhost CA]# openssl req -new -x509 -key private/cakey.pem -out cacert.pem -days
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 ( letter code) [GB]:CN
State or Province Name (full name) [Berkshire]:HENAN
Locality Name (eg, city) [Newbury]:ZHENGZHOU
Organization Name (eg, company) [My Company Ltd]:ZKYT
Organizational Unit Name (eg, section) []:TECH
Common Name (eg, your name or your server's hostname) []:ca.linuxpanda.com
Email Address []:caadmin@linuxpanda.com

• 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：输出证书文件位置

2.3 查看自己的证书

[root@localhost CA]$ openssl x509 -in cacert.pem  -noout -text

2.4 初始化工作环境

[root@localhost CA]# touch index.txt serial   #创建index.txt,serial文件
[root@localhost CA]# echo  >serial          #写入初始值

[root@localhost CA]# mkdir csr crl newcerts        #创建目录csr,crl newcerts

• 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
• csr:证书请求目录
• crl:吊销列表目标
• newcerts：证书目录

3.节点申请证书

3.1生成密钥对

[root@localhost CA]# cd /etc/httpd/ssl                       #进入httpd的配置子目录ssl
-bash: cd: /etc/httpd/ssl: No such file or directory
[root@localhost CA]# ls
cacert.pem  index.txt  private  serial
[root@localhost CA]# cd /etc/httpd/　　　　　　　　　　　　　　　#查看目录情况
[root@localhost httpd]# ls
conf  conf.d  logs  modules  run　　
[root@localhost httpd]# mkdir ssl　　　　　　　　　　　　　　    #创建ssl目录，用于存放秘钥
[root@localhost httpd]# (umask ; openssl genrsa -out ssl/httpd.key ) #生成私钥
Generating RSA private key,  bit long modulus
.+++
............................+++
e is  (0x10001)

3.2生成证书请求

[root@localhost httpd]# openssl req -new -key ssl/httpd.key  -out ssl/httpd.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 ( letter code) [GB]:CN
State or Province Name (full name) [Berkshire]:HENAN
Locality Name (eg, city) [Newbury]:ZHENGZHOU
Organization Name (eg, company) [My Company Ltd]:ZKYT
Organizational Unit Name (eg, section) []:TECH
Common Name (eg, your name or your server's hostname) []:tech1.linuxpanda.com
Email Address []:

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

3.3证书请求文件发送到服务器

[root@localhost httpd]# scp ssl/httpd.csr 192.168.137.100:/etc/pki/CA/csr/httpd.csr
root@192.168.137.100's password:
httpd.csr                                                                                                                                                         %      .0KB/s   :
[root@localhost httpd]# ls /etc/pki/CA/csr
httpd.csr

4 CA服务器签署证书

4.1 CA服务器上签署证书

[root@localhost CA]# openssl ca -in csr/httpd.csr  -out httpd.crt -days
Using configuration from /etc/pki/tls/openssl.cnf
Error opening CA private key ../../CA/private/cakey.pem
:error::system library:fopen:No such file or directory:bss_file.c::fopen('../../CA/private/cakey.pem','r')
:error::BIO routines:FILE_CTRL:system lib:bss_file.c::
unable to load CA private key
[root@localhost CA]# vim /etc/pki/tls/
cert.pem     certs/       misc/        openssl.cnf  private/
[root@localhost CA]# vim /etc/pki/tls/openssl.cnf      #编辑配置文件，修改../../CA 为 /etc/pki/CA 即可
[root@localhost CA]# openssl ca -in csr/httpd.csr  -out httpd.crt -days
Using configuration from /etc/pki/tls/openssl.cnf
I am unable to access the /etc/pki/CA/newcerts directory          #没有创建newcerts 目录
/etc/pki/CA/newcerts: No such file or directory
[root@localhost CA]# mkdir newcerts                               #创建目录newcerts
[root@localhost CA]# openssl ca -in csr/httpd.csr  -out httpd.crt -days
Using configuration from /etc/pki/tls/openssl.cnf
Check that the request matches the signature
Signature ok
Certificate Details:
        Serial Number:  (0x1)
        Validity
            Not Before: Mar  ::  GMT
            Not After : Mar  ::  GMT
        Subject:
            countryName               = CN
            stateOrProvinceName       = HENAN
            organizationName          = ZKYT
            organizationalUnitName    = TECH
            commonName                = tech1.linuxpanda.com
        X509v3 extensions:
            X509v3 Basic Constraints:
                CA:FALSE
            Netscape Comment:
                OpenSSL Generated Certificate
            X509v3 Subject Key Identifier:
                B3:E9::1A::::F1:A2::B4::C6:FD:5A:AF:8E::CB:C3
            X509v3 Authority Key Identifier:
                keyid::0F:4A:D3::3F::D7:FA::3C:0A::9B:6F:6A::::

Certificate is to be certified until Mar  ::  GMT ( days)
Sign the certificate? [y/n]:y

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

4.2将证书发送给请求者

[root@localhost CA]# scp httpd.crt  192.168.137.100:/etc/httpd/ssl
root@192.168.137.100's password:
httpd.crt      

5 吊销证书

5.1节点请求吊销

[root@localhost CA]# openssl x509 -in httpd.crt  -noout -serial -subject
serial=
subject= /C=CN/ST=HENAN/O=ZKYT/OU=TECH/CN=tech1.linuxpanda.com

• 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

5.2节点提交的serial和subject信息是否和index.txt的信息一致

[root@localhost CA]# cat index.txt
V    180325021521Z            unknown    /C=CN/ST=HENAN/O=ZKYT/OU=TECH/CN=tech1.linuxpanda.com

5.3 吊销证书

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

5.4生成吊销证书的编号（如果是第一次吊销）

root@localhost CA]# echo  > crlnumber

5.5更新吊销证书列表

我们虽然上面已经吊销了证书， 但是别人是无法知道的。 只能通过crl来让别人知道谁谁谁的证书被吊销了。

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

5.6查看crl文件内容

[root@localhost CA]# openssl crl -in crl/ca.crl -noout -text
Certificate Revocation List (CRL):
        Version  (0x1)
        Signature Algorithm: sha1WithRSAEncryption
        Issuer: /C=CN/ST=HENAN/L=ZHENGZHOU/O=ZKYT/OU=TECH/CN=ca.linuxpanda.com/emailAddress=caadmin@linuxpanda.com
        Last Update: Mar  ::  GMT
        Next Update: Apr  ::  GMT
        CRL extensions:
            X509v3 CRL Number: 

Revoked Certificates:
    Serial Number:
        Revocation Date: Mar  ::  GMT
    Signature Algorithm: sha1WithRSAEncryption
        :::c1:0e:9d:f5::b9:b5:ae:2b:be:ce:::8d:e7:
        7a::eb:e0::5b:bd::aa::e5:dd:a6::f4:4c:e0:e5:
        c2::2d::ff:2e::ad::9d:::0f:6d:dc:0f:a7:fc:
        e8::0e:6f:f2:cf:a8:ed::ea:ff::bb:4b::c7:a1::
        :b0:::0c:cc:db:5b:f9:b3:::e5:fd:bd:f7::a2:
        4a::d9:b9:ad:7d:a7::::c2:bb:::dd:c3:::
        :b2:f9:dc:7f:4c:d7::::ad:bd:::e6:8d:1c:9d:
        e1:d8:ab:::a8::c7:a1::2a:b4:fb:dd:c4:b9:::
        :2c:e5::7f:::1d:e5::a7:::d7:a8:8b:a5:5f:
        da::4e:7c:f8:::a7:5e:2a::c1:b2::c8:c1::df:
        :fa:2d:ba::e4:b8:::d0:fb:e3:9e:c9:3b::6b:ae:
        8a:a5:b6:6e:9e::ed:5d::ab:6f:a9::6d:b2::5d::
        ce:0f::3e:f6:e6:f5:e8:a5:ef:d2:d1:d7:eb:bc:e7::1b:
        fc::6b::b2::c2::8a:e3:::f9::a5:6e:a1:4d:
        2d::e2: