在笔者之前的博文《关于httpd 2.x，mod_auth_mysql模块的安装配置以及对aes加密的支持》中，所提及到的mod_auth_mysql模块，是专门用于Apache httpd的第三方认证模块。在本文中，将介绍在Nginx上面相对应的一个模块，nginx_auth_mysql。
准备工作
下载nginx_auth_mysql的源代码
CentOS7服务器，nginx源码包(笔者使用nginx1.12.0稳定版)
支持nginx的编译环境，并安装有openssl开发包
存在libmysqlclient以及libmysqld动态库
nginx_auth_mysql的源代码文件如下所示：
$ ls config crypt_private.c crypt_private.h LICENSE ngx_http_auth_mysql_module.c README
查看一下config配置文件，其内容如下所示：
$ cat config.bak ngx_addon_name=ngx_http_auth_mysql_module HTTP_MODULES="$HTTP_MODULES ngx_http_auth_mysql_module" NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_auth_mysql_module.c $ngx_addon_dir/crypt_private.c" CORE_LIBS="$CORE_LIBS -lcrypto -lmysqlclient" USE_MD5=YES
由上述配置文件的格式，可以看出是专门进行静态编译的第三方模块。由于在Nginx 1.9.11版本之后，已经支持以动态模块的方式来支持第三方扩展，并且由上述配置文件的内容，初步判定可以将其修改为动态模块的编译配置，因此这里将其编译为动态库，以供Nginx进行加载。
关于配置文件的修改以及动静模块的转换，参照如下两篇文章：
经过修改之后的config文件内容如下所示：
ngx_addon_name=ngx_http_auth_mysql_module if test -n "$ngx_module_link"; then ngx_module_type=HTTP ngx_module_name=$ngx_addon_name ngx_module_srcs="$ngx_addon_dir/ngx_http_auth_mysql_module.c $ngx_addon_dir/crypt_private.c" ngx_module_incs="/usr/include/mysql" ngx_module_libs="-lcrypto -lmysqlclient -lmysqld -L/usr/lib64/mysql" . auto/module else HTTP_MODULES="$HTTP_MODULES ngx_http_auth_mysql_module" NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_auth_mysql_module.c $ngx_addon_dir/crypt_private.c" CORE_LIBS="$CORE_LIBS -lcrypto -lmysqlclient" USE_MD5=YES fi
在编译的时候，添加上--add-dynamic-module选项，将模块添加进来。笔者这里使用的是--add-dynamic-module=/root/nginx-1.12.0/nginx_auth_mysql，其中的nginx_auth_mysql目录用于存放模块的源代码。
在进行编译的过程中，笔者遇到了如下错误：
/root/nginx-1.12.0/nginx_auth_mysql/ngx_http_auth_mysql_module.c: In function ‘ngx_http_auth_mysql_check_md5’: /root/nginx-1.12.0/nginx_auth_mysql/ngx_http_auth_mysql_module.c:488:19: error: ‘MD5_DIGEST_LENGTH’ undeclared (first use in this function) u_char md5_str[2*MD5_DIGEST_LENGTH + 1]; ^ /root/nginx-1.12.0/nginx_auth_mysql/ngx_http_auth_mysql_module.c:488:19: note: each undeclared identifier is reported only once for each function it appears in /root/nginx-1.12.0/nginx_auth_mysql/ngx_http_auth_mysql_module.c:489:9: error: unused variable ‘md5_digest’ [-Werror=unused-variable] u_char md5_digest[MD5_DIGEST_LENGTH]; ^ /root/nginx-1.12.0/nginx_auth_mysql/ngx_http_auth_mysql_module.c:488:9: error: unused variable ‘md5_str’ [-Werror=unused-variable] u_char md5_str[2*MD5_DIGEST_LENGTH + 1];
从上面的报错结果来看，可以发现，是MD5_DIGEST_LENGTH没有定义，甚是奇怪……
经过排查，在ngx_http_auth_mysql_module.c文件里面，所引用的头文件当中，似乎确实并未包含MD5_DIGEST_LENGTH的定义，ngx_md5.h的全部内容如下所示：
$ cat ngx_md5.h
/*
* Copyright (C) Igor Sysoev
* Copyright (C) Nginx, Inc.
*/
#ifndef _NGX_MD5_H_INCLUDED_
#define _NGX_MD5_H_INCLUDED_
#include <ngx_config.h>
#include <ngx_core.h>
typedef struct {
uint64_t bytes;
uint32_t a, b, c, d;
u_char buffer[64];
} ngx_md5_t;
void ngx_md5_init(ngx_md5_t *ctx);
void ngx_md5_update(ngx_md5_t *ctx, const void *data, size_t size);
void ngx_md5_final(u_char result[16], ngx_md5_t *ctx);
#endif /* _NGX_MD5_H_INCLUDED_ */通过对比一个老版本的nginx源代码，发现确实有所不同，下面的是老版本的nginx的头文件，可以看出，引用了openssl的md5头文件定义：
...... ...... #if (NGX_HAVE_MD5) #if (NGX_HAVE_OPENSSL_MD5_H) #include <openssl/md5.h> #else #include <md5.h> #endif ...... ......
通过查阅md5头文件，得到其定义的值为16，因此，在nginx-1.12.0的ngx_md5.h里面，添加如下定义：
#define MD5_DIGEST_LENGTH 16
保存之后，重新编译，成功通过。
编译完成之后，在objs文件夹里面生成了所需要的模块:
$ ls objs/ | grep auth ngx_http_auth_mysql_module_modules.c ngx_http_auth_mysql_module_modules.o ngx_http_auth_mysql_module.so
将ngx_http_auth_mysql_module.so拷贝到对应的模块目录里面，至此完成了初步的模块安装任务。
配置内容
在nginx.conf文件中的main段里面添加如下一行，代表需要加载该模块：
load_module modules/ngx_http_auth_mysql_module.so;
笔者使用默认主机/auth路径下的auth.html进行测试：
$ cat /opt/nginx/html/auth/auth.html <h1>auth page</h1>
在该模块的README文档中，详细介绍了模块使用的配置参数，如下所示：
== CONFIGURATION ==
It is activated by adding several configuration options:
auth_mysql_realm: HTTP basic authentiaction realm. Required.
auth_mysql_host: the host of the MySQL server. Default is 127.0.0.1.
auth_mysql_port: on which port to connect to the MySQL server. Default is 3306.
auth_mysql_user: username for connection to the MySQL server. Default is root.
auth_mysql_password: password for connection to the MySQL server. Default is empty.
auth_mysql_database: name of the database. Required.
auth_mysql_table: name of the table, which holds the user record.
You can have more than one table separated by comas. Default is users.auth_mysql_user_column: name of the username column. Default is username.
auth_mysql_password_column: name of the password column. Default is password.
auth_mysql_conditions: Additional SQL conditions. They will be placed after and AND.
Default is empty string.auth_mysql_group_table: name of the table, which holds the groups information.
You can have more than one table separated by comas. Default is the users table.auth_mysql_group_column: name of the group name column. Default is name.
auth_mysql_group_conditions: Additional SQL conditions applied only in group queries.
They will be placed after an AND. Default is empty string.auth_mysql_encryption_type: the format of the password field. Should be one of:
none: the password is stored in plaintext in the database;
md5: in the database is stored a md5 hash of the password;
phpass: a portable php hash of the password is stored. See:
http://www.openwall.com/phpass/ for more information.
The default is md5.auth_mysql_allowed_users: whitespace delimited list of allowed users.
auth_mysql_allowed_groups: whitespace delimited list of allowed groups.
If both allowed_users and allowed_groups are defined, either of them has to satisfied.
笔者这里使用mysql数据库创建认证用户的内容如下所示，创建nginx数据库，在nginx数据库里面添加一个nginx_auth的数据表，存放user字段和password字段，并且password字段用md5进行加密：
$ mysql Welcome to the MariaDB monitor. Commands end with ; or \g. Your MariaDB connection id is 3337 Server version: 5.5.44-MariaDB MariaDB Server Copyright (c) 2000, 2015, Oracle, MariaDB Corporation Ab and others. Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement. MariaDB [(none)]> use nginx; Reading table information for completion of table and column names You can turn off this feature to get a quicker startup with -A Database changed MariaDB [nginx]> show tables; +-----------------+ | Tables_in_nginx | +-----------------+ | nginx_auth | +-----------------+ 1 row in set (0.00 sec) MariaDB [nginx]> select * from nginx_auth; +------+----------------------------------+ | user | password | +------+----------------------------------+ | tom | d077f244ddf8r70e5ea758bd8352fcd8 | +------+----------------------------------+ 1 row in set (0.00 sec)
在nginx.conf配置文件当中使用的配置如下所示：
......
......
location /auth {
root /opt/nginx/html;
index auth.html;
auth_mysql_realm "authentication";
auth_mysql_host "192.168.5.181";
auth_mysql_port "3306";
auth_mysql_user "nginx";
auth_mysql_password "nginx";
auth_mysql_database "nginx";
auth_mysql_table "nginx_auth";
auth_mysql_user_column "user";
auth_mysql_password_column "password";
auth_mysql_encryption_type "md5";
}
......
......reload一下nginx，利用curl命令进行测试，得到的结果如下所示，可见模块正常运行：
$ curl -u tom:right_password http://192.168.5.181/auth/ <h1>auth page</h1> $ curl -u tom:wrong_password http://192.168.5.181/auth/ <html> <head><title>401 Authorization Required</title></head> <body bgcolor="white"> <center><h1>401 Authorization Required</h1></center> <hr><center>nginx/1.12.0</center> </body> </html>
其他事项
在httpd上面使用的mod_auth_mysql模块，自带了aes加密算法，但是在nginx上面使用的此模块，默认却没有添加该项功能，不过该模块的作者在README中提到：
== WRITING A NEW ECNRYPTION TYPE ==
Add an entry in thengx_http_auth_mysql_enctypesarray. It has to be a struct
with two elements:
ngx_str_t id
The name under which it should be referenced in the config file
ngx_uint_t (*checker)(ngx_http_request_t *r, ngx_str_t sent_password, ngx_str_t actual_password)
A function, which given the request (mostly used for logging and memory allocation through its r->pool),
the password sent by the user and the password in the database has to determine whether they match.
If they match it should return NGX_OK, if they don’t it should return NGX_DECLINED. If other error
occures, it should log it and return NGX_ERR.Currently salts aren‘t supported, but if there are schemes, which require them it is quite easy.Questions/patches may be sent to Nikolay Bachiyski, nikolay@automattic.com
似乎只能等待牛人进行二次开发了......
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原文地址：http://jiangche00.blog.51cto.com/4377920/1941560
