NginxLua实现WAF防火墙

Web应用防护系统（也称：网站应用级入侵防御系统 。英文：Web Application Firewall，简称： WAF）。利用国际上公认的一种说法：Web应用 防火墙是通过执行一系列针对HTTP/HTTPS的 安全策略来专门为Web应用提供保护的一款产品。

nginx+lua安装方法

方法一：安装nginx并整合lua模块

安装LuaJIT

LuaJIT的意思是Lua Just-In-Time，是即时的Lua代码解释器。必须去github下载否则运行是会出现报错，项目地址：https://github.com/openresty/luajit2

git clone https://github.com/openresty/luajit2.git
cd luajit2
make PREFIX=/usr/local/luajit
make install PREFIX=/usr/local/luajit

安装完成后将如下环境变量加入到/etc/profile中,并执行source /etc/profile

export LUAJIT_LIB=/usr/local/luajit/lib
export LUAJIT_INC=/usr/local/luajit/include/luajit-2.1

安装ngx_devel_kit(NDK)

版本地址:https://github.com/vision5/ngx_devel_kit/tags

下载并解压

cd /mnt
wget https://github.com/vision5/ngx_devel_kit/archive/v0.3.1.tar.gz
tar -xzvf v0.3.1.tar.gz

安装最新版的lua-nginx-module

版本地址：https://github.com/openresty/lua-nginx-module/tags

下载最新稳定版并解压

cd /mnt
wget https://github.com/openresty/lua-nginx-module/archive/v0.10.15.tar.gz
tar -xzvf v0.10.16rc5.tar.gz

编译Nginx并加入lua模块

cd /mnt/nginx-1.18.0
./configure  --prefix=/etc/nginx --sbin-path=/usr/sbin/nginx  --modules-path=/usr/lib64/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --pid-path=/var/run/nginx.pid --lock-path=/var/run/nginx.lock --user=nginx --group=nginx --with-http_gzip_static_module --with-http_realip_module --with-http_ssl_module --with-openssl=/mnt/openssl-1.1.1g --with-zlib=/mnt/zlib-1.2.11 --with-pcre=/mnt/pcre-8.44 --add-module=/mnt/lua-nginx-module-0.10.15 --add-module=/mnt/ngx_devel_kit-0.3.1

::: tip 提示

其中的openssl,pcre以及zlib需要额外下载并解压到/mnt目录下

:::

启动nginx发现报错

[root@k8s-node mnt]# nginx
nginx: error while loading shared libraries: libluajit-5.1.so.2: cannot open shared object file: No such file or directory

解决办法

echo "/usr/local/luajit/lib/" >> /etc/ld.so.conf
ldconfig

在默认的location中加入如下指令，访问测试

content_by_lua 'ngx.say("hello, lua")';

安装成功

方法二 ：直接安装OpenResty

::: tip

OpenResty是一个基于Nginx与 Lua 的高性能 Web 平台，其内部集成了大量精良的 Lua 库、第三方模块以及大多数的依赖项。用于方便地搭建能够处理超高并发、扩展性极高的动态 Web 应用、Web 服务和动态网关。

:::

最新版Openresty

cd /opt 
tar -xzvf openresty-1.15.8.3.tar.gz
./configure --prefix=/opt/openresty --with-pcre=/opt/pcre-8.44 --with-zlib=/opt/zlib-1.2.11 --with-openssl=/opt/openssl-1.1.1g --with-poll_module --with-http_v2_module --with-http_realip_module --with-http_addition_module --with-stream --with-stream_ssl_module --with-stream_ssl_preread_module --with-http_ssl_module

gmake
gmake install

按方法一测试可以访问即可

WAF模块安装

ngx_lua_waf项目地址：https://github.com/loveshell/ngx_lua_waf.git

这里以Openresty为例，Nginx方法类似

cd /opt/openresty/lualib
git clone https://github.com/loveshell/ngx_lua_waf.git waf

在openresry的nginx.conf配置文件中http{}代码块添加如下配置项：

lua_package_path "/opt/openresty/lualib/waf/?.lua";
lua_shared_dict limit 10m;
init_by_lua_file  "/opt/openresty/lualib/waf/init.lua";           
access_by_lua_file "/opt/openresty/lualib/waf/waf.lua";

整个waf目录结构如下：

[root@k8s-node lualib]# tree waf
waf
├── config.lua
├── init.lua
├── wafconf
│   ├── args
│   ├── cookie
│   ├── post
│   ├── url
│   ├── user-agent
│   └── whiteurl
└── waf.lua

1 directory, 9 files

config.lua中定义了整个waf的配置，详细如下：

#拦截规则的存放目录
RulePath = "/opt/openresty/lualib/waf/wafconf/"
#是否开启拦截日志记录
attacklog = "on"
#拦截日志的记录目录，nginx的worker进程需要对该目录有权限
logdir = "/opt/openresty/nginx/logs/"
#是否开启url拦截
UrlDeny="on"
#是否开启拦截重定向
Redirect="on"
#是否开启cookie攻击防护
CookieMatch="on"
#是否开启post攻击防护
postMatch="on"
whiteModule="on"
#禁止访问的文件扩展名
black_fileExt={"php","jsp"}
#IP地址白名单
ipWhitelist={"127.0.0.1"}
#IP地址黑名单
ipBlocklist={"1.0.0.1"}
#是否开启CC攻击防护
CCDeny="on"
#定义CC攻击速率，该例为每60秒100次请求,表示60秒内最多同一页面最多刷新100次，超过后自动拉入黑名单，60秒后解除,不影响访问其他页面
CCrate="100/60"
#定义重定向后的html页面
html=[[...]]

启动nginx发现报错

[root@jssong conf]# nginx
nginx: [alert] failed to load the 'resty.core' module (https://github.com/openresty/lua-resty-core); ensure you are using an OpenResty release from https://openresty.org/en/download.html (reason: ...openresty/lualib/lua-resty-core/lib/resty/core/regex.lua:14: module 'resty.lrucache' not found:
        no field package.preload['resty.lrucache']
        no file '/opt/openresty/lualib/waf/resty/lrucache.lua'
        no file '/opt/openresty/lualib/lua-resty-core/lib/resty/lrucache.lua'
        no file '/opt/openresty/site/lualib/resty/lrucache.so'
        no file '/opt/openresty/lualib/resty/lrucache.so'
        no file './resty/lrucache.so'
        no file '/usr/local/lib/lua/5.1/resty/lrucache.so'
        no file '/opt/openresty/luajit/lib/lua/5.1/resty/lrucache.so'
        no file '/usr/local/lib/lua/5.1/loadall.so'
        no file '/opt/openresty/site/lualib/resty.so'
        no file '/opt/openresty/lualib/resty.so'
        no file './resty.so'
        no file '/usr/local/lib/lua/5.1/resty.so'
        no file '/opt/openresty/luajit/lib/lua/5.1/resty.so'
        no file '/usr/local/lib/lua/5.1/loadall.so') in /opt/openresty/nginx/conf/nginx.conf:133

原因是因为缺少 lua-resty-core 模块，从而找不到这些信息，所以我们要下载lua-resty-core模块然后引入到openresty

cd /opt/openresty/lualib
git clone https://github.com/openresty/lua-resty-core.git

lua-resty-core结构目录如下，主要是用到lib下的lua

[root@jssong lualib]# tree lua-resty-core
lua-resty-core
├── dist.ini
├── lib
│   ├── ngx
│   │   ├── balancer.lua
│   │   ├── balancer.md
│   │   ├── base64.lua
│   │   ├── base64.md
│   │   ├── errlog.lua
│   │   ├── errlog.md
│   │   ├── ocsp.lua
│   │   ├── ocsp.md
│   │   ├── pipe.lua
│   │   ├── pipe.md
│   │   ├── process.lua
│   │   ├── process.md
│   │   ├── re.lua
│   │   ├── re.md
│   │   ├── req.lua
│   │   ├── req.md
│   │   ├── resp.lua
│   │   ├── resp.md
│   │   ├── semaphore.lua
│   │   ├── semaphore.md
│   │   ├── ssl
│   │   │   ├── session.lua
│   │   │   └── session.md
│   │   ├── ssl.lua
│   │   └── ssl.md
│   └── resty
│       ├── core
│       │   ├── base64.lua
│       │   ├── base.lua
│       │   ├── ctx.lua
│       │   ├── exit.lua
│       │   ├── hash.lua
│       │   ├── misc.lua
│       │   ├── ndk.lua
│       │   ├── phase.lua
│       │   ├── regex.lua
│       │   ├── request.lua
│       │   ├── response.lua
│       │   ├── shdict.lua
│       │   ├── time.lua
│       │   ├── uri.lua
│       │   ├── utils.lua
│       │   ├── var.lua
│       │   └── worker.lua
│       └── core.lua
├── Makefile
├── README.markdown
├── t
│   ├── balancer.t
│   ├── balancer-timeout.t
│   ├── cert
│   │   ├── chain
│   │   │   ├── chain-bad0.pem
│   │   │   ├── chain-bad2.pem
│   │   │   ├── chain.der
│   │   │   ├── chain.pem
│   │   │   ├── root-ca.crt
│   │   │   ├── test-com-bad.key.pem
│   │   │   ├── test-com.key.der
│   │   │   └── test-com.key.pem
│   │   ├── ocsp
│   │   │   ├── chain.pem
│   │   │   ├── ocsp-req.der
│   │   │   ├── ocsp-resp.der
│   │   │   ├── ocsp-resp-no-certs.der
│   │   │   ├── ocsp-resp-signed-by-orphaned.der
│   │   │   ├── ocsp-resp-signed-by-orphaned-no-certs.der
│   │   │   ├── revoked-chain.pem
│   │   │   ├── revoked-ocsp-resp.der
│   │   │   ├── test-com.crt
│   │   │   └── wrong-issuer-order-chain.pem
│   │   ├── test2.crt
│   │   ├── test2.key
│   │   ├── test.crt
│   │   ├── test.crt.der
│   │   ├── test.key
│   │   └── test.key.der
│   ├── count.t
│   ├── ctx.t
│   ├── decode-base64.t
│   ├── encode-base64.t
│   ├── errlog-raw-log.t
│   ├── errlog.t
│   ├── exit.t
│   ├── lib
│   │   └── helper.lua
│   ├── master-pid-single-process.t
│   ├── master-pid.t
│   ├── md5-bin.t
│   ├── md5.t
│   ├── misc.t
│   ├── ndk.t
│   ├── ngx-req.t
│   ├── ngx-resp.t
│   ├── ocsp.t
│   ├── os-getenv-hup.t
│   ├── os-getenv.t
│   ├── phase.t
│   ├── pipe-cpu-affinity.t
│   ├── pipe-stderr.t
│   ├── pipe-stdin.t
│   ├── pipe-stdout.t
│   ├── pipe.t
│   ├── process-type-cache.t
│   ├── process-type-hup.t
│   ├── process-type-master.t
│   ├── process-type-privileged-agent.t
│   ├── process-type-single.t
│   ├── process-type-worker.t
│   ├── re-base.t
│   ├── re-bugs.t
│   ├── re-find.t
│   ├── re-gmatch.t
│   ├── re-match.t
│   ├── re-opt.t
│   ├── request.t
│   ├── re-split.t
│   ├── response.t
│   ├── re-sub.t
│   ├── semaphore.t
│   ├── sha1-bin.t
│   ├── shared.t
│   ├── shdict.t
│   ├── ssl-session-fetch.t
│   ├── ssl-session-store.t
│   ├── ssl.t
│   ├── status.t
│   ├── stream
│   │   ├── balancer.t
│   │   ├── balancer-timeout.t
│   │   ├── errlog-raw-log.t
│   │   ├── errlog.t
│   │   ├── misc.t
│   │   ├── os-getenv-hup.t
│   │   ├── os-getenv.t
│   │   ├── re-base.t
│   │   ├── re-find.t
│   │   ├── re-gmatch.t
│   │   ├── re-match.t
│   │   ├── re-opt.t
│   │   ├── request.t
│   │   ├── re-split.t
│   │   ├── re-sub.t
│   │   ├── semaphore.t
│   │   ├── shdict.t
│   │   ├── ssl.t
│   │   └── time.t
│   ├── TestCore
│   │   └── Stream.pm
│   ├── TestCore.pm
│   ├── time.t
│   ├── uri.t
│   ├── utils.t
│   ├── var.t
│   ├── worker-count-5.t
│   └── worker.t
└── valgrind.suppress

在openrestry的配置文件nginx.conf配置文件中lua_package_path追加代码

lua_package_path "/opt/openresty/lualib/waf/?.lua;/opt/openresty/lualib/lua-resty-core/lib/?.lua;;";

启动nginx,报错消失。

拦截测试：

#出现拦截页面即表示安装成功
curl http://www.example.com/test.php?id=../etc/passwd

相关日志：

192.168.0.101 [2020-06-20 01:44:01] "GET localhost/index.php?id=/../../../etc/passwd" "-"  "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36" "\.\./"
?.lua;/opt/openresty/lualib/lua-resty-core/lib/?.lua;;";

启动nginx,报错消失。

拦截测试：

#出现拦截页面即表示安装成功
curl http://www.example.com/test.php?id=../etc/passwd

相关日志：

192.168.0.101 [2020-06-20 01:44:01] "GET localhost/index.php?id=/../../../etc/passwd" "-"  "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.106 Safari/537.36" "\.\./"