使用免费SSL证书让网站支持HTTPS访问

下面是使用Let’s Encrypt提供的SSL证书,记录配置SSL的安装实践过程。

下面两种方法均在 CentOS7 环境下操作滴。

certbot-auto

刚看到新闻,Let’s Encrypt发布的 ACME v2 现已正式支持通配符HTTPS证书,就立马使用上了 certbot

安装

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# 下载
wget https://dl.eff.org/certbot-auto

# 设为可执行权限
chmod a+x certbot-auto

申请证书

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# 注xxx.com请根据自己的域名自行更改
./certbot-auto --server https://acme-v02.api.letsencrypt.org/directory -d "*.xxx.com" --manual --preferred-challenges dns-01 certonly

从服务器到目的地的出站端口 443 是否被防火墙阻止

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nc -vz acme-v02.api.letsencrypt.org 443 -w2
# Ncat: Version 7.50 ( https://nmap.org/ncat )
# Ncat: Connected to 23.77.214.183:443.
# Ncat: 0 bytes sent, 0 bytes received in 0.07 seconds.

执行完这一步之后,会下载一些需要的依赖,稍等片刻之后,会提示输入邮箱

邮箱很重要,主要用于安全提醒,以及续期提醒

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Complete!
Creating virtual environment...
Installing Python packages...
Installation succeeded.
Saving debug log to /var/log/letsencrypt/letsencrypt.log
Plugins selected: Authenticator manual, Installer None
Enter email address (used for urgent renewal and security notices) (Enter 'c' to
- cancel):
+ cancel): 这里填写邮箱地址

-------------------------------------------------------------------------------
Please read the Terms of Service at
https://letsencrypt.org/documents/LE-SA-v1.2-November-15-2017.pdf. You must
agree in order to register with the ACME server at
https://acme-v02.api.letsencrypt.org/directory
-------------------------------------------------------------------------------
- (A)gree/(C)ancel:
+ (A)gree/(C)ancel: A

-------------------------------------------------------------------------------
Would you be willing to share your email address with the Electronic Frontier
Foundation, a founding partner of the Let's Encrypt project and the non-profit
organization that develops Certbot? We'd like to send you email about EFF and
our work to encrypt the web, protect its users and defend digital rights.
-------------------------------------------------------------------------------
- (Y)es/(N)o:
+ (Y)es/(N)o: Y
Obtaining a new certificate
Performing the following challenges:
dns-01 challenge for showgold.com

-------------------------------------------------------------------------------
NOTE: The IP of this machine will be publicly logged as having requested this
certificate. If you're running certbot in manual mode on a machine that is not
your server, please ensure you're okay with that.

Are you OK with your IP being logged?
-------------------------------------------------------------------------------
- (Y)es/(N)o:
+ (Y)es/(N)o: Y

-------------------------------------------------------------------------------
Please deploy a DNS TXT record under the name
+ _acme-challenge.xxx.com
with the following value:

+ VBsfRHG______4t_drxcEFQlyOS0puAlJFypAYQTA

Before continuing, verify the record is deployed.
-------------------------------------------------------------------------------
Press Enter to Continue
+ 不要心急着按回车,先执行dig _acme-challenge.xxx.com txt确认解析记录是否生效,生效之后再回去按回车确认
Waiting for verification...

IMPORTANT NOTES:
- Congratulations! Your certificate and chain have been saved at:
+ /etc/letsencrypt/live/xxx.com/fullchain.pem
Your key file has been saved at:
+ /etc/letsencrypt/live/xxx.com/privkey.pem
Your cert will expire on 2018-06-13. To obtain a new or tweaked
version of this certificate in the future, simply run certbot-auto
again. To non-interactively renew *all* of your certificates, run
+ "certbot-auto renew"
- If you like Certbot, please consider supporting our work by:

Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
Donating to EFF: https://eff.org/donate-le

注意:
申请通配符证书是要经过DNS认证的,按照提示,前往域名后台添加对应的DNS TXT记录。
添加之后,不要心急着按回车,先执行 dig xxxx.xxx.com txt确认解析记录是否生效,生效之后再回去按回车确认

看到 Congratulations 你就大功告成了!

续期HTTPS证书

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certbot-auto renew
certbot-auto delete -d chat.xxx.cn # 删除证书
./certbot-auto delete --cert-name xxx.com # 删除证书重新生成

⚠️ 注意这里会有升级操作,并且有安装 Python 包,有时候会非常慢,不要停止,停止操作可能会造成麻烦。

查看证书过期时间

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openssl x509 -noout -dates -in /etc/letsencrypt/live/<你的域名>/cert.pem

nginx应用该证书的例子

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server {
server_name xxx.com;
listen 443 http2 ssl;
ssl on;
ssl_certificate /etc/letsencrypt/live/xxx.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/xxx.com/privkey.pem;

location / {
proxy_pass http://127.0.0.1:6666;
}
}

无法应用到主域名

如需把主域名也增加到证书的覆盖范围,请在开始申请证书步骤的那个指令把主域名也加上-d "xxx.com",如下:

需要注意的是,这样的话需要修改两次解析记录

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./certbot-auto --server https://acme-v02.api.letsencrypt.org/directory -d "*.xxx.com" -d "xxx.com" --manual --preferred-challenges dns-01 certonly

certbot-nginx

安装 EPEL 仓库

首先要安装 Let's Encrypt 证书用的工具,这个可以在CentOS 的 EPEL 仓库里找到它,在找到它之前,先检查是否存在 EPEL 源:

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# 进入目录检查是否存在 EPEL 源,一般情况文件名称 epel.repo
cd /etc/yum.repos.d/

如果不存在可以直接安装

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sudo yum install epel-release -y

安装签发证书工具

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sudo yum install certbot-nginx -y
# 查看版本
certbot --version
# certbot 0.21.1

申请证书

报nginx命令不存在错误

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sudo certbot --nginx
# Saving debug log to /var/log/letsencrypt/letsencrypt.log
# The nginx plugin is not working; there may be problems with your existing configuration.
# The error was: NoInstallationError()
# 如果你报上面错误运行下面,命令解决问题
which nginx # 查看目录
#输出 /usr/local/nginx/sbin/nginx
yum info nginx

解决方法

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ln -s /usr/local/nginx/sbin/nginx /usr/bin/nginx
ln -s /usr/local/nginx/conf/ /etc/nginx

报nginx配置文件目录不对错误

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sudo certbot --nginx
# Saving debug log to /var/log/letsencrypt/letsencrypt.log
# Error while running nginx -c /etc/nginx/nginx.conf -t.

# nginx: [emerg] open() "/etc/nginx/nginx.conf" failed (2: No such file or directory)
# nginx: configuration file /etc/nginx/nginx.conf test failed

# The nginx plugin is not working; there may be problems with your existing configuration.
# The error was: MisconfigurationError('Error while running nginx -c /etc/nginx/nginx.conf -t.\n\nnginx: [emerg] open() "/etc/nginx/nginx.conf" failed (2: No such file or directory)\nnginx: configuration file /etc/nginx/nginx.conf test failed\n',)

解决方法,这个解决方法就是让certbot认为你的,你的配置存在,并且将SSL配置写入你的nginx配置文件中,然后拷贝配置到你的默认 nginx 配置中。哈哈为了方便 nginx 启动不用指定配置,也没有看到 certbot 工具提供指定目录的命令,暂时我就这么解决吧。

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# nginx 默认配置文件目录不 /etc/nginx/ 目录下,
# 需要拷贝/usr/local/nginx/conf目录下的全部文件
# 复制到/etc/nginx/目录下
cp -r /usr/local/nginx/conf/* /etc/nginx/

# 编辑开机启动将所有目录换成/etc/nginx/
vim /lib/systemd/system/nginx.service
cp /lib/systemd/system/nginx.service{,.bak}

# 测试配置是否正确
nginx -t -c /etc/nginx/nginx.conf

正确之后将nginx中的 SSL 配置复制到你的原来正在运行的配置中,在默认安装目录配置/usr/local/nginx/conf/。会在配置中生成如下内容,主要是复制这个。

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{
ssl_certificate /etc/letsencrypt/live/chat.wangchujiang.com/fullchain.pem; # managed by Certbot
ssl_certificate_key /etc/letsencrypt/live/chat.wangchujiang.com/privkey.pem; # managed by Certbot
}

正式申请申请证书

首先运行证书生成命令,选择你要配置SSL证书的网站,这个是基于你网站已经在nginx中配置好了的情况。

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sudo certbot --nginx certonly
# Saving debug log to /var/log/letsencrypt/letsencrypt.log
# Plugins selected: Authenticator nginx, Installer nginx
# Starting new HTTPS connection (1): acme-v01.api.letsencrypt.org
#
# Which names would you like to activate HTTPS for?
# -------------------------------------------------------------------------------
# 1: chat.wangchujiang.com
# 2: g.wangchujiang.com
# 3: pan.wangchujiang.com
# -------------------------------------------------------------------------------
# Select the appropriate numbers separated by commas and/or spaces, or leave input
# blank to select all options shown (Enter 'c' to cancel): 2

上面选择了g.wangchujiang.com生成证书,下面是验证过程,添加 certonly参数表示只生成证书。

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# Obtaining a new certificate
# Performing the following challenges:
# tls-sni-01 challenge for g.wangchujiang.com
# Waiting for verification...
# Cleaning up challenges
#
# IMPORTANT NOTES:
# - Congratulations! Your certificate and chain have been saved at:
# /etc/letsencrypt/live/g.wangchujiang.com/fullchain.pem
# Your key file has been saved at:
# /etc/letsencrypt/live/g.wangchujiang.com/privkey.pem
# Your cert will expire on 2018-03-13. To obtain a new or tweaked
# version of this certificate in the future, simply run certbot
# again. To non-interactively renew *all* of your certificates, run
# "certbot renew"
# - If you like Certbot, please consider supporting our work by:
#
# Donating to ISRG / Let's Encrypt: https://letsencrypt.org/donate
# Donating to EFF: https://eff.org/donate-le

上面生成成功了,可以添加到 nginx 配置中,这下完事儿了,下面是一端nginx的配置实例。

配置nginx

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# http 重定向到 https
server {
listen 80;
server_name g.wangchujiang.com;
rewrite ^ https://$http_host$request_uri? permanent;
# Enables or disables emitting nginx version on error pages and in the "Server" response header field.
server_tokens off;
}
# https 的配置
server {
listen 443 ssl;
server_name g.wangchujiang.com;

ssl_certificate /etc/letsencrypt/live/g.wangchujiang.com/fullchain.pem;
ssl_certificate_key /etc/letsencrypt/live/g.wangchujiang.com/privkey.pem;
# 禁止在header中出现服务器版本,防止黑客利用版本漏洞攻击
server_tokens off;
# 设置ssl/tls会话缓存的类型和大小。如果设置了这个参数一般是shared,buildin可能会参数内存碎片,默认是none,和off差不多,停用缓存。如shared:SSL:10m表示我所有的nginx工作进程共享ssl会话缓存,官网介绍说1M可以存放约4000个sessions。
ssl_session_cache shared:SSL:1m;

# 客户端可以重用会话缓存中ssl参数的过期时间,内网系统默认5分钟太短了,可以设成30m即30分钟甚至4h。
ssl_session_timeout 5m;

# 选择加密套件,不同的浏览器所支持的套件(和顺序)可能会不同。
# 这里指定的是OpenSSL库能够识别的写法,你可以通过 openssl -v cipher 'RC4:HIGH:!aNULL:!MD5'(后面是你所指定的套件加密算法) 来看所支持算法。
ssl_ciphers HIGH:!aNULL:!MD5;

# 设置协商加密算法时,优先使用我们服务端的加密套件,而不是客户端浏览器的加密套件。
ssl_prefer_server_ciphers on;

location / {
root html;
index index.html index.htm;
}
}

参考阅读

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