这个是笔者对论坛主机的FTP服务进行注册用户验证，论坛采用的是VBB，看了看VBB的密码加密方式，MD5，FAINT。
PROFTPD的MOD_SQL模块并不支持MD5。VBB是直接调用MYSQL的MD5()函数进行密码加密。怎么办？HACK！笔者用的PROFTPD是最新的Proftpd 1.2.8，mod_sql 版本是 4.10，查了一下 mod_sql.c 文件，发现增加一种验证方式还是很简单的，当然这个要归功mod_sql.c的程序架构设计得不错。
下面是笔者修改后得mod_sql.c的部分代码，有中文的地方是笔者加的。
#include "conf.h"
#include "privs.h"
#include "mod_sql.h"
#define _MOD_VERSION "mod_sql/4.10"
#ifdef HAVE_CRYPT_H
#include
#endif
#ifdef HAVE_LIMITS_H
#include
#endif
/**************/
/* 引入md5头文件 */
#include
/**************/
/* Uncomment the following define to allow OpenSSL hashed password checking;
* you'll also need to link with OpenSSL's crypto library ( -lcrypto )
*/
/* #define HAVE_OPENSSL */
#ifdef HAVE_OPENSSL
#include
#endif
/* default information for tables and fields */
#define MOD_SQL_DEF_USERTABLE "users"
#define MOD_SQL_DEF_USERNAMEFIELD "userid"
#define MOD_SQL_DEF_USERUIDFIELD "uid"
#define MOD_SQL_DEF_USERGIDFIELD "gid"
#define MOD_SQL_DEF_USERPASSWORDFIELD "password"
#define MOD_SQL_DEF_USERSHELLFIELD "shell"
#define MOD_SQL_DEF_USERHOMEDIRFIELD "homedir"
#define MOD_SQL_DEF_GROUPTABLE "groups"
#define MOD_SQL_DEF_GROUPNAMEFIELD "groupname"
#define MOD_SQL_DEF_GROUPGIDFIELD "gid"
#define MOD_SQL_DEF_GROUPMEMBERSFIELD "members"
/* default minimum id / default uid / default gid info.
* uids and gids less than MOD_SQL_MIN_USER_UID and
* MOD_SQL_MIN_USER_GID, respectively, get automatically
* mapped to the defaults, below. These can be
* overridden using directives
*/
#define MOD_SQL_MIN_USER_UID 999
#define MOD_SQL_MIN_USER_GID 999
#define MOD_SQL_DEF_UID 65533
#define MOD_SQL_DEF_GID 65533
#define MOD_SQL_BUFSIZE 32
/* Named Query defines */
#define SQL_SELECT_C "SELECT"
#define SQL_INSERT_C "INSERT"
#define SQL_UPDATE_C "UPDATE"
#define SQL_FREEFORM_C "FREEFORM"
/* authmask defines */
#define SQL_AUTH_USERS (1<<0)
#define SQL_AUTH_GROUPS (1<<1)
#define SQL_AUTH_USERS_DEFINITIVE (1<<2)
#define SQL_AUTH_GROUPS_DEFINITIVE (1<<3)
#define SQL_AUTH_USERSET (1<<4)
#define SQL_AUTH_GROUPSET (1<<5)
#define SQL_FAST_USERSET (1<<6)
#define SQL_FAST_GROUPSET (1<<7)
#define SQL_GROUPS (cmap.authmask & SQL_AUTH_GROUPS)
#define SQL_USERS (cmap.authmask & SQL_AUTH_USERS)
#define SQL_GROUPSET (cmap.authmask & SQL_AUTH_GROUPSET)
#define SQL_USERSET (cmap.authmask & SQL_AUTH_USERSET)
#define SQL_FASTGROUPS (cmap.authmask & SQL_FAST_GROUPSET)
#define SQL_FASTUSERS (cmap.authmask & SQL_FAST_USERSET)
#define SQL_GROUPGOD (cmap.authmask & SQL_AUTH_GROUPS_DEFINITIVE)
#define SQL_USERGOD (cmap.authmask & SQL_AUTH_USERS_DEFINITIVE)
/*
* externs, function signatures.. whatever necessary to make
* the compiler happy..
*/
extern pr_response_t *resp_list,*resp_err_list;
static char *_sql_where(pool *p, int cnt, ...);
MODRET cmd_getgrent(cmd_rec *);
MODRET cmd_setgrent(cmd_rec *);
pool *sql_pool;
/*
* cache typedefs
*/
#define CACHE_SIZE 13
typedef struct cache_entry {
struct cache_entry *list_next;
struct cache_entry *bucket_next;
void *data;
} cache_entry_t;
/* this struct holds invariant information for the current session */
static struct
{
/*
* info valid after getpwnam
*/
char *authuser; /* current authorized user */
struct passwd *authpasswd; /* and their passwd struct */
/*
* generic status information
*/
int status; /* is mod_sql on? */
int authmask; /* authentication mask.
* see set_sqlauthenticate for info */
/*
* user table and field information
*/
char *usrtable; /* user info table name */
char *usrfield; /* user name field */
char *pwdfield; /* user password field */
char *uidfield; /* user uid field */
char *gidfield; /* user gid field */
char *homedirfield; /* user homedir field */
char *shellfield; /* user login shell field */
char *userwhere; /* users where clause */
/*
* group table and field information
*/
char *grptable; /* group info table name */
char *grpfield; /* group name field */
char *grpgidfield; /* group gid field */
char *grpmembersfield; /* group members field */
char *groupwhere; /* groups where clause */
/*
* other information
*/
array_header *authlist; /* auth handler list */
char *defaulthomedir; /* default homedir if no field specified */
int buildhomedir; /* create homedir if it doesn't exist? */
uid_t minid; /* users UID must be this or greater */
uid_t minuseruid; /* users UID must be this or greater */
gid_t minusergid; /* users UID must be this or greater */
uid_t defaultuid; /* default UID if none in database */
gid_t defaultgid; /* default GID if none in database */
cache_entry_t *curr_group; /* next group in group array for getgrent */
cache_entry_t *curr_passwd; /* next passwd in passwd array for getpwent */
int group_cache_filled;
int passwd_cache_filled;
unsigned char negative_cache; /* cache negative as well as positive lookups */
/*
* mod_ratio data -- someday this needs to be removed from mod_sql
*/
char *sql_fstor; /* fstor int(11) NOT NULL DEFAULT '0', */
char *sql_fretr; /* fretr int(11) NOT NULL DEFAULT '0', */
char *sql_bstor; /* bstor int(11) NOT NULL DEFAULT '0', */
char *sql_bretr; /* bretr int(11) NOT NULL DEFAULT '0', */
char *sql_frate; /* frate int(11) NOT NULL DEFAULT '5', */
char *sql_fcred; /* fcred int(2) NOT NULL DEFAULT '15', */
char *sql_brate; /* brate int(11) NOT NULL DEFAULT '5', */
char *sql_bcred; /* bcred int(2) NOT NULL DEFAULT '150000', */
/*
* precomputed strings
*/
char *usrfields;
char *grpfields;
}
cmap;
/*
* cache functions
*/
typedef unsigned int ( * val_func ) ( const void * );
typedef int ( * cmp_func ) ( const void *, const void * );
typedef struct {
/* memory pool for this object */
pool *pool;
/* cache buckets */
cache_entry_t *buckets[ CACHE_SIZE ];
/* cache functions */
val_func hash_val;
cmp_func cmp;
/* list pointers */
cache_entry_t *head;
/* list size */
unsigned int nelts;
} cache_t;
cache_t *group_name_cache;
cache_t *group_gid_cache;
cache_t *passwd_name_cache;
cache_t *passwd_uid_cache;
static cache_t *make_cache( pool *p, val_func hash_val, cmp_func cmp )
{
cache_t *res;
if ( ( p == NULL ) || ( hash_val == NULL ) ||
( cmp == NULL ) )
return NULL;
res = ( cache_t * ) pcalloc( p, sizeof( cache_t ) );
res->pool = p;
res->hash_val = hash_val;
res->cmp = cmp;
res->head = NULL;
res->nelts = 0;
return res;
}
static cache_entry_t *cache_addentry( cache_t *cache, void *data )
{
cache_entry_t *entry;
int hashval;
if ( ( cache == NULL ) || ( data == NULL ) )
return NULL;
/* create the entry */
entry = ( cache_entry_t * ) pcalloc( cache->pool,
sizeof( cache_entry_t ) );
entry->data = data;
/* deal with the list */
if ( cache->head == NULL ) {
cache->head = entry;
} else {
entry->list_next = cache->head;
cache->head = entry;
}
/* deal with the buckets */
hashval = cache->hash_val( data ) % CACHE_SIZE;
if ( cache->buckets[ hashval ] == NULL ) {
cache->buckets[ hashval ] = entry;
} else {
entry->bucket_next = cache->buckets[ hashval ];
cache->buckets[ hashval ] = entry;
}
cache->nelts++;
return entry;
}
static void *cache_findvalue( cache_t *cache, void *data )
{
cache_entry_t *entry;
int hashval;
if ( ( cache == NULL ) || ( data == NULL ) ) return NULL;
hashval = cache->hash_val( data ) % CACHE_SIZE;
entry = cache->buckets[ hashval ];
while ( entry != NULL ) {
if ( cache->cmp( data, entry->data ) )
break;
else
entry = entry->bucket_next;
}
return ( ( entry == NULL ) ? NULL : entry->data );
}
cmd_rec *_sql_make_cmd(pool * cp, int argc, ...)
{
pool *newpool = NULL;
cmd_rec *c = NULL;
va_list args;
int i = 0;
newpool = make_sub_pool( cp );
c = pcalloc(newpool, sizeof(cmd_rec));
c->argc = argc;
c->stash_index = -1;
c->pool = newpool;
c->argv = pcalloc(newpool, sizeof(void *) * (argc));
c->tmp_pool = newpool;
va_start(args, argc);
for (i = 0; i < argc; i++)
c->argv[i] = (void *) va_arg(args, char *);
va_end(args);
return c;
}
void _sql_free_cmd( cmd_rec *cmd )
{
destroy_pool( cmd->pool );
return;
}
static void _sql_check_cmd(cmd_rec *cmd, char *msg)
{
if ((!cmd) || (!cmd->tmp_pool)) {
log_pri(PR_LOG_ERR, _MOD_VERSION ": '%s' was passed an invalid cmd_rec. "
"Shutting down.", msg);
sql_log(DEBUG_WARN, "'%s' was passed an invalid cmd_rec. Shutting down.",
msg);
end_login(1);
}
return;
}
static modret_t *_sql_check_response(modret_t * mr)
{
if (!MODRET_ISERROR(mr))
return mr;
sql_log(DEBUG_WARN, "%s", "unrecoverable backend error");
sql_log(DEBUG_WARN, "error: '%s'", mr->mr_numeric);
sql_log(DEBUG_WARN, "message: '%s'", mr->mr_message);
end_login(1);
/* make the compiler happy */
return NULL;
}
static modret_t * _sql_dispatch(cmd_rec *cmd, char *cmdname)
{
modret_t *mr = NULL;
int i = 0;
for(i = 0; sql_cmdtable[i].command; i++)
if(!strcmp(cmdname,sql_cmdtable[i].command)) {
pr_signals_block();
mr = sql_cmdtable[i].handler(cmd);
pr_signals_unblock();
return mr;
}
sql_log(DEBUG_WARN, "unknown backend handler '%s'", cmdname );
return ERROR(cmd);
}
static char *_sql_strip_spaces( pool *p, char *str )
{
char *start = NULL, *finish = NULL;
if (!str) return NULL;
/* first, find the non-whitespace start of the given string */
for (start = str; isspace((int) *start); start++);
/* now, find the non-whitespace end of the given string */
for (finish = &str[strlen(str)-1]; isspace((int) *finish); finish--);
*++finish = ';
/* the space-stripped string is, then, everything from start to finish */
return pstrdup( p, start );
}
/*****************************************************************
*
* AUTHENTICATION FUNCTIONS
*
*****************************************************************/
static modret_t *check_auth_crypt(cmd_rec * cmd, const char *c_clear,
const char *c_hash)
{
int success = 0;
if (*c_hash == ') return ERROR_INT(cmd, PR_AUTH_BADPWD);
success = !strcmp((char *) crypt(c_clear, c_hash), c_hash);
return success ? HANDLED(cmd) : ERROR_INT(cmd, PR_AUTH_BADPWD);
}
static modret_t *check_auth_plaintext(cmd_rec * cmd, const char *c_clear,
const char *c_hash)
{
int success = 0;
if (*c_hash == ' ) return ERROR_INT(cmd, PR_AUTH_BADPWD);
success = !strcmp(c_clear, c_hash);
return success ? HANDLED(cmd) : ERROR_INT(cmd, PR_AUTH_BADPWD);
}
static modret_t *check_auth_empty(cmd_rec * cmd, const char *c_clear,
const char *c_hash)
{
int success = 0;
success = !strcmp(c_hash, "");
return success ? HANDLED(cmd) : ERROR_INT(cmd, PR_AUTH_BADPWD);
}
static modret_t *check_auth_backend(cmd_rec * cmd, const char *c_clear,
const char *c_hash)
{
modret_t * mr = NULL;
if (*c_hash == ' ) return ERROR_INT(cmd, PR_AUTH_BADPWD);
mr = _sql_dispatch( _sql_make_cmd(cmd->tmp_pool, 3, "default",
c_clear, c_hash),
"sql_checkauth" );
return mr;
}
/******************************************************/
/* 增加 MD5 验证函数*, 简单之至, 照猫画虎*/
static modret_t *check_auth_md5(cmd_rec * cmd, const char *c_clear, const char *c_hash)
{
int success = 0;
size_t len = strlen(c_clear);
char buf[33];
/* specifically disallow empty passwords */
if (*c_hash == ' ) return ERROR_INT(cmd, PR_AUTH_BADPWD);
MD5Data(c_clear, len, buf); /* 调用MD5函数 */
success = !strcmp(buf, c_hash);
return success ? HANDLED(cmd) : ERROR_INT(cmd, PR_AUTH_BADPWD);
}
/****************************************************/
#ifdef HAVE_OPENSSL
static modret_t *check_auth_openssl(cmd_rec * cmd, const char *c_clear,
const char *c_hash)
{
/*
* c_clear : plaintext password provided by user
* c_hash : combination digest name and hashed
* value, of the form {digest}hash
*/
EVP_MD_CTX mdctx;
EVP_ENCODE_CTX EVP_Encode;
const EVP_MD *md;
unsigned char md_value[EVP_MAX_MD_SIZE];
int md_len, returnValue;
char buff[EVP_MAX_KEY_LENGTH];
char *digestname; /* ptr to name of the digest function */
char *hashvalue; /* ptr to hashed value we're comparing to */
char *copyhash; /* temporary copy of the c_hash string */
if (c_hash[0] != '{') {
return ERROR_INT(cmd, PR_AUTH_BADPWD);
}
/*
* we need a copy of c_hash
*/
copyhash = pstrdup(cmd->tmp_pool, c_hash);
digestname = copyhash + 1;
hashvalue = (char *) strchr(copyhash, '}');
if (hashvalue == NULL) {
return ERROR_INT(cmd, PR_AUTH_BADPWD);
}
*hashvalue = ';
hashvalue++;
OpenSSL_add_all_digests();
md = EVP_get_digestbyname(digestname);
if (!md) {
return ERROR_INT(cmd, PR_AUTH_BADPWD);
}
EVP_DigestInit(&mdctx, md);
EVP_DigestUpdate(&mdctx, c_clear, strlen(c_clear));
EVP_DigestFinal(&mdctx, md_value, &md_len);
EVP_EncodeInit(&EVP_Encode);
EVP_EncodeBlock(buff, md_value, md_len);
returnValue = strcmp(buff, hashvalue);
return returnValue ? ERROR_INT(cmd, PR_AUTH_BADPWD) : HANDLED(cmd);
}
#endif
/*
* support for general-purpose authentication schemes
*/
#define PLAINTEXT_AUTH_FLAG 1<<0
#define CRYPT_AUTH_FLAG 1<<1
#define BACKEND_AUTH_FLAG 1<<2
#define EMPTY_AUTH_FLAG 1<<3
/* 插入MD5验证模式,把OPENSSL往后推，OPENSSL本来是 1<<4 */
#define MD5_AUTH_FLAG 1<<4
/***************/
#ifdef HAVE_OPENSSL
#define OPENSSL_AUTH_FLAG 1<<5
#endif
typedef modret_t *(*auth_func_ptr) (cmd_rec *, const char *, const char *);
typedef struct
{
char *name;
auth_func_ptr check_function;
int flag;
}
auth_type_entry;
static auth_type_entry supported_auth_types[] = {
{"Plaintext", check_auth_plaintext, PLAINTEXT_AUTH_FLAG},
{"Crypt", check_auth_crypt, CRYPT_AUTH_FLAG},
{"Backend", check_auth_backend, BACKEND_AUTH_FLAG},
{"Empty", check_auth_empty, EMPTY_AUTH_FLAG},
{"MD5", check_auth_md5, MD5_AUTH_FLAG}, /* 这里往验证类型条目结构里增加MD5验证 */
#ifdef HAVE_OPENSSL
{"OpenSSL", check_auth_openssl, OPENSSL_AUTH_FLAG},
#endif
/*
* add additional encryption types below
*/
{NULL, NULL, 0}
};
static auth_type_entry *get_auth_entry(char *name)
{
auth_type_entry *ate = supported_auth_types;
while (ate->name) {
if (!strcasecmp(ate->name, name)) {
return ate;
}
ate++;
}
return NULL;
}
