rhel6.3下使用openssl来生成CA证书并颁发证书实例解析

一、配置OPENSSL
[root@test1 /]# rpm -qa|grep openssl
openssl-1.0.0-20.el6_2.5.i686
[root@test1 /]# cd /etc/pki/tls
[root@test1 tls]# ls
cert.pem  certs  misc  openssl.cnf  private
[root@test1 tls]# vim openssl.cnf
####################################################################
[ CA_default ]

dir             = /etc/pki/CA           # Where everything is kept  （CA中心的目录）
certs           = $dir/certs            # Where the issued certs are kept (证书保存目录）
crl_dir         = $dir/crl              # Where the issued crl are kept  (被吊销证书的目录)
database        = $dir/index.txt        # database index file.  (证书索引文件)
#unique_subject = no                    # Set to 'no' to allow creation of
                                        # several ctificates with same subject.
new_certs_dir   = $dir/newcerts         # default place for new certs.(经过CA中心签名的证书备份目录)

certificate     = $dir/my-ca.crt        # The CA certificate （CA的公钥文件名）
serial          = $dir/serial           # The current serial number （CA中心的颁发证书序列号）
crlnumber       = $dir/crlnumber        # the current crl number （已吊销证书序列号）
                                        # must be commented out to leave a V1 CRL
crl             = $dir/my-ca.crl        # The current CRL （证书吊销列表）
private_key     = $dir/private/my-ca.key # The private key （CA私钥文件）
RANDFILE        = $dir/private/.rand    # private random number file

x509_extensions = usr_cert              # The extentions to add to the cert

default_days    = 365                   # how long to certify for  （证书有效期）
default_crl_days= 30                    # how long before next CRL
default_md      = default               # use public key default MD
preserve        = no                    # keep passed DN ordering

[ policy_match ]       #此段为证书相关信息选项，其中match指定的项，要求被签名证书一定要与CA的对应项一致。
countryName  = match
stateOrProvinceName = match
organizationName = match
organizationalUnitName = optional
commonName  = supplied
emailAddress  = optional

#
[ req_distinguished_name ]
countryName                     = Country Name (2 letter code)
countryName_default             = CN    （国家代码需要自己修改）
countryName_min                 = 2
countryName_max                 = 2

stateOrProvinceName             = State or Province Name (full name)
stateOrProvinceName_default    = Hebei   （州或省名需要自己修改）

localityName                    = Locality Name (eg, city)
localityName_default    = Beijing    （地点名称需要自己修改）

0.organizationName              = Organization Name (eg, company)
0.organizationName_default      = Tianli Company    (组织或公司名需要自己修改)

[root@test1 tls]# cd ../CA/
[root@test1 CA]# ls
certs  crl  newcerts  private
注：需要有这几个目录，如果没有可以自己新建
[root@test1 CA]# touch index.txt
[root@test1 CA]# echo "00"> serial
[root@test1 CA]# ls
certs  crl  index.txt  newcerts  private  serial

二、创建密钥过程
创建私钥
[root@test1 CA]#(umask 077;openssl genrsa -out private/my-ca.key -des3 2048)
Generating RSA private key, 2048 bit long modulus
............................................................+++
..........+++
e is 65537 (0x10001)
Enter pass phrase for private/my-ca.key:
Verifying - Enter pass phrase for private/my-ca.key:

由私钥生成公钥
[root@test1 CA]#openssl req -new -x509 -key private/my-ca.key -days 365 > my-ca.crt
Enter pass phrase for private/my-ca.key:
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) [CN]:CN
State or Province Name (full name) []:Hebei
Locality Name (eg, city) [Beijing]:Beijing
Organization Name (eg, company) [Default Company Ltd]:Tianli Company
Organizational Unit Name (eg, section) []:
Common Name (eg, your name or your server's hostname) []:test1
Email Address []:
[root@test1 CA]# ls
certs  crl  index.txt  my-ca.crt  newcerts  private  serial

三、客户端验证CA服务
主机端(192.168.1.130)上：
[root@test1 CA]#yum -y install httpd
[root@test1 CA]#service httpd start
[root@test1 CA]#mkdir -p /var/www/html/yum
[root@test1 CA]#cp my-ca.crt /var/www/html/yum   将my-ca.crt,即公钥放到http服务器，供其他人下载

另外客户端(192.168.1.117)上：
[root@test2 Desktop]#openssl genrsa 1024 > test2.key
Generating RSA private key, 1024 bit long modulus
.....................++++++
.......++++++
e is 65537 (0x10001)

[root@test2 Desktop]#openssl req -new -key test2.key -out dovecot.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) []:Hebei
Locality Name (eg, city) [Default City]:Beijing
Organization Name (eg, company) [Default Company Ltd]:Tianli Company
Organizational Unit Name (eg, section) []:
Common Name (eg, your name or your server's hostname) []:test2
Email Address []:

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

[root@test2 Desktop]# scp dovecot.csr [email protected]:/root/
[email protected]'s password:
dovecot.csr                                   100%  668     0.7KB/s   00:00   

四、服务端签发CA证书
在CA认证服务器上
[root@test1 ~]# openssl ca -in dovecot.csr -out dovecot.cst
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/my-ca.key:
Check that the request matches the signature
Signature ok
Certificate Details:
        Serial Number: 1 (0x1)
        Validity
            Not Before: Jan 22 10:44:36 2013 GMT
            Not After : Jan 22 10:44:36 2014 GMT
        Subject:
            countryName               = CN
            stateOrProvinceName       = Hebei
            organizationName          = Tianli Company
            commonName                = test2
        X509v3 extensions:
            X509v3 Basic Constraints:
                CA:FALSE
            Netscape Comment:
                OpenSSL Generated Certificate
            X509v3 Subject Key Identifier:
                56:69:58:12:67:C7:FC:9E:AC:70:1D:2A:2C:56:A4:E1:61:97:B2:23
            X509v3 Authority Key Identifier:
                keyid:4C:45:25:5F:60:7F:F8:6E:6F:B4:53:C4:FB:BD:A3:C6:82:AE:2A:62

Certificate is to be certified until Jan 22 10:44:36 2014 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
最后签发成功。

补充：在签发证书的过程中容易出现的两个问题
[root@test1 ~]# openssl ca -in dovecot.csr -out dovecot.cst
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/my-ca.key:
unable to load number from /etc/pki/CA/serial
error while loading serial number
3078239980:error:0D066096:asn1 encoding routines:a2i_ASN1_INTEGER:short line:f_int.c:215:
提示error while loading serial number，一般是因为serial文件中没有赋初值
解决办法
[root@test1 ~]#cd /etc/pki/CA
[root@test1 CA]# echo "00" >serial
[root@test1 CA]# cat serial
00

还有一个问题在CA签名时，最后出现failed to update database错误
[root@test1 ~]#openssl ca -in dovecot.csr -out dovecot.crt
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/my-ca.key:
Check that the request matches the signature
Signature ok
Certificate Details:
        Serial Number: 2 (0x2)
        Validity
            Not Before: Jan 23 02:23:39 2013 GMT
            Not After : Jan 23 02:23:39 2014 GMT
        Subject:
            countryName               = CN
            stateOrProvinceName       = Hebei
            organizationName          = Tianli Company
            commonName                = test2
        X509v3 extensions:
            X509v3 Basic Constraints:
                CA:FALSE
            Netscape Comment:
                OpenSSL Generated Certificate
            X509v3 Subject Key Identifier:
                96:86:28:B7:ED:2E:96:79:32:88:7E:C3:23:37:02:BC:43:1C:76:87
            X509v3 Authority Key Identifier:
                keyid:4C:45:25:5F:60:7F:F8:6E:6F:B4:53:C4:FB:BD:A3:C6:82:AE:2A:62

Certificate is to be certified until Jan 23 02:23:39 2014 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

Certificate is to be certified until Jan 23 02:17:38 2014 GMT (365 days)
Sign the certificate? [y/n]:y
failed to update database
TXT_DB error number 2
遇到这个错误，只需要清空/etc/pki/CA/index.txt的内容再签发就可以成功了。

吊销证书：
[root@test1 ~]# openssl ca -revoke my-ca.crt
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/my-ca.key:
Adding Entry with serial number B443BCCFCD08C1CD to DB for /C=CN/ST=Hebei/L=Beijing/O=Default Company Ltd/CN=test1
Revoking Certificate B443BCCFCD08C1CD.
Data Base Updated

生成吊销证书列表
[root@test1 ~]# openssl ca -gencrl -out my-ca.crl
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/my-ca.key:
unable to load number from /etc/pki/CA/crlnumber
error while loading CRL number
3079087852:error:0D066096:asn1 encoding routines:a2i_ASN1_INTEGER:short line:f_int.c:215:
出现error while loading CRL number，解决办法给crlnumber赋值
[root@test1 ~]# echo "00" >/etc/pki/CA/crlnumber
[root@test1 ~]# openssl ca -gencrl -out my-ca.crl
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for /etc/pki/CA/private/my-ca.key:
[root@test1 ~]# ls
anaconda-ks.cfg  dovecot.csr  install.log         my-ca.crl  Public
dead.letter      dovecot.cst  install.log.syslog  my-ca.crt  Templates
Desktop          dovecot.pem  Music              test2.key
Documents        Downloads    Pictures   Videos
[root@test1 ~]# cat my-ca.crl
-----BEGIN X509 CRL-----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-----END X509 CRL-----

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