rlm_ldap.c

RADIUS 服务器介绍 RADIUS服务器支持标准的RADIUS协议

/*
 * rlm_ldap.c LDAP authorization and authentication module.
 * 
 * 
 * This module is based on LDAP patch to Cistron radiusd by James Golovich 
 * <[e-mail]>, which in turn was based mostly on a Mysql+Cistron patch 
 * from <[e-mail]>
 * 
 * 17 Jan 2000,	Adrian Pavlykevych <[e-mail]>
 *	- OpenLDAP SDK porting, basic TLS support, LDAP authorization,
 *	  fault tolerance with multiple LDAP server support 
 * 24 May 2000,	Adrian Pavlykevych <[e-mail]> 
 *	- Converting to new configuration file format, futher improvements
 *	  in fault tolerance, threaded operation
 * 12 Dec 2000,	Adrian Pavlykevych <[e-mail]> 
 *	- Added preliminary support for multiple instances
 * 	- moved all instance configuration into dynamicly allocated structure
 *	- Removed connection maintenance thread and all attempts for multihreading
 *	  the module itself. OpenLDAP SDK is not thread safe when used with shared
 *	  LDAP connection.
 *	- Added configuration option for defining LDAP attribute of user object,
 *	  which controls remote access.
 * 16 Feb 2001, Hannu Laurila <[e-mail]>
 * 	- LDAP<->RADIUS attribute mappings are now read from a file
 *  	- Support for generic RADIUS check and reply attribute.
 * Jun 2001, Kostas Kalevras <[e-mail]>
 *	- Fix: check and reply attributes from LDAP _replace_ existing ones
 *	- Added "default_profile" directive, which points to radiusProfile 
 *	  object, which contains default values for RADIUS users
 *	- Added "profile_attribute" directive, which specifies user object 
 *	  attribute pointing to radiusProfile object.
 * Nov 2001, Kostas Kalevras <[e-mail]>
 *	- Added support for adding the user password to the check. Based on
 *	  the password_header directive rlm_ldap will strip the
 *	  password header if needed. This will make support for CHAP much easier.
 *	- Added module messages when we reject a user.
 *	- Added ldap_groupcmp to allow searching for user group membership.
 *	- Added ldap_xlat to allow ldap urls in xlat strings. Something like:
 *	  %{ldap:ldap:///dc=company,dc=com?cn?sub?uid=user}
 * Nov 2001, Gordon Tetlow <[e-mail]>
 *	- Do an xlat on the access_group attribute.
 * Dec 2001, Kostas Kalevras <[e-mail]>
 *	- Added ldap caching for the default/regular profiles and group entries.
 *	- Fixed a memory leak in ldap_xlat.
 *	- Removed dict_attrbyname from ldap_pairget. They are not needed.
 *	- Moved the radius_xlat's for filter and basedn in ldap_authenticate() to
 *	  the right place.
 *	- Made the module thread safe. We create a connection pool and each thread
 *	  will call ldap_get_conn to lock one of the ldap connections and release with
 *	  a call to ldap_release_conn when it has finished.
 *	- Request only the user attributes that interest us (radius attributes,regular
 *	  profile,user password and access attribute).
 * Mar 2002, Kostas Kalevras <[e-mail]>
 *	- Fixed a bug where the ldap server will kill the idle connections from the ldap
 *	  connection pool. We now check if ldap_search returns LDAP_SERVER_DOWN and try to
 *	  reconnect if it does. Bug noted by Dan Perik <[e-mail]>
 * May 2002, Kostas Kalevras <[e-mail]>
 *	- Instead of the Group attribute we now have the Ldap-Group attribute, to avoid
 *	  collisions with other modules
 *	- If perform_search fails check the ld != NULL before using it. Based on a bug report
 *	  by John <[e-mail]>
 * Jun 2002, Kostas Kalevras <[e-mail]>
 *	- Add the ability to do a paircmp on the check items. Add a compare_check_items boolean
 *	  configuration directive which defaults to no. If it is set then we will do a compare
 *	- Add another configuration directive. access_attr_used_for_allow. If it is set to yes
 *	  then the access_attr will be used to allow user access. If it is set to no then it will
 *	  be used to deny user access.
 *	- Remember to free inst->atts in ldap_detach()
 *	- Add a forgotten ldap_free_urldesc in ldap_xlat()
 *	- Add a variable locked in the LDAP_CONN structure. We use this to avoid deadlocks. The mutex
 *	  we are using is of type fast and can deadlock if the same thread tries to relock it. That
 *	  could happen in case of calls to xlat.
 *	- When ldap_search returns NO_SUCH_OBJECT don't return fail but notfound
 * Jul 2002, Kostas Kalevras <[e-mail]>
 *	- Fix the logic when we get an LDAP_SERVER_DOWN or we have conn->ld == NULL in perform_search
 *	- Try to minimize the penalty of having the ldap server go down. The comments before
 *	  MAX_FAILED_CONNS_* definitions should explain things.
 *	- Check for a number of error codes from ldap_search and log corresponding error messages
 *	  We should only reconnect when that can help things.
 *	- In ldap_groupcmp instead of first searching for the group object and then checking user
 *	  group membership combine them in one ldap search operation. That should make group
 *	  membership checks a lot faster.
 *	- Remember to do ldap_release_conn and ldap_msgfree when we do paircmp and the result is reject
 * Aug 2002, Kostas Kalevras <[e-mail]>
 *	- Add support for group membership attribute inside the user entry in ldap_groupcmp. The attribute
 *	  can either contain the name or the DN of the group. Added the groupmembership_attribute
 *	  configuration directive
 *	- Move the ldap_{get,release}_conn in ldap_groupcmp so that we hold a connection for the minimum time.
 *	- Now that ldap_groupcmp is complete we really don't need access_group. Removed it.
 *	- Remember to free groupmembership_attribute in ldap_detach
 *	- Don't delete existing generic attributes in ldap_pairget when adding new ones. Since generic attributes
 *	  have operators we don't need to try to be cleaver.
 * Sep 2002, Kostas Kalevras <[e-mail]>
 *	- Fix a crash in ldap_pairget when the attribute value is larger than the buffer size
 *	  Bug report by Stefan Radovanovici <[e-mail]>
 *	- If we add a check item then use the == operator. Based on an idea by Allister Maguire <[e-mail]>
 *	- Only add a failure message for bind as user failed in ldap_authenticate if the result of ldap_connect was
 *	  RLM_MODULE_REJECT
 *	- Make tls_mode a configurable option. Patch from John <[e-mail]>
 *	- Allow multiple regular profiles for an entry
 * Oct 2002, Kostas Kalevras <[e-mail]>
 *	- Disable cache after searching for the default profile
 *	- Use the MAX_FAILED_CONNS_* in ldap_authenticate() when calling ldap_connect()
 * Nov 2002, Kostas Kalevras <[e-mail]>
 *	- Set LDAP version to V3 before binding. Now freeradius should work with openldap21
 * Dec 2002, Kostas Kalevras <[e-mail]>
 *	- Set default values for the server and basedn parameters
 * Feb 2003, Kostas Kalevras <[e-mail]>
 *	- Add support for ldap_initialize. That way we can specify the server as an ldap url.
 *	  Based on ideas from Derrik Pates <[e-mail]>
 * Mar 2003, Kostas Kalevras <[e-mail]>
 * 	- Add an ldap_escape_func. Escape the * character from the filter so that we can avoid
 * 	  the trivial DoS of username=*
 * 	- Remove the caching code. It does not exist in openldap21.
 *	  Based on a report from Mike Denka <[e-mail]>
 * May 2003, Kostas Kalevras <[e-mail]>
 *	- Don't do a double free on the attribute maps. Bug noted by Derrik Pates <[e-mail]>
 *	- Apply a patch from Alexander M. Pravking <[e-mail]> to do an xlat on the
 *	  retrieved attributes.
 */
static const char rcsid[] = "$Id: rlm_ldap.c,v 1.108 2003/07/07 19:07:08 aland Exp $";

#include "autoconf.h"

#include	<sys/types.h>
#include	<sys/socket.h>
#include	<sys/time.h>
#include	<netinet/in.h>

#include	<stdio.h>
#include	<stdlib.h>
#include	<netdb.h>
#include	<pwd.h>
#include	<time.h>
#include	<ctype.h>
#include	<string.h>

#include	<lber.h>
#include        <ldap.h>

#include	<errno.h>
#include	<unistd.h>
#include	<pthread.h>

#include        "libradius.h"
#include	"radiusd.h"
#include	"conffile.h"
#include	"modules.h"
#include	"rad_assert.h"

#define MAX_FILTER_STR_LEN	1024
#define TIMELIMIT 5

/*
 * These are used in case ldap_search returns LDAP_SERVER_DOWN
 * In that case we do conn->failed_conns++ and then check it:
 * If conn->failed_conns <= MAX_FAILED_CONNS_START then we try
 * to reconnect
 * conn->failed_conns is also checked on entrance in perform_search:
 * If conn->failed_conns > MAX_FAILED_CONNS_START then we don't
 * try to do anything and we just do conn->failed_conns++ and
 * return RLM_MODULE_FAIL
 * if conn->failed_conns >= MAX_FAILED_CONNS_END then we give it
 * another chance and we set it to MAX_FAILED_CONNS_RESTART and
 * try to reconnect.
 *
 *
 * We are assuming that the majority of the LDAP_SERVER_DOWN cases
 * will either be an ldap connection timeout or a temporary ldap
 * server problem.
 * As a result we make a few attempts to reconnect hoping that the problem
 * will soon go away. If it does not go away then we just return
 * RLM_MODULE_FAIL on entrance in perform_search until conn->failed_conns
 * gets to MAX_FAILED_CONNS_END. After that we give it one more chance by
 * going back to MAX_FAILED_CONNS_RESTART
 *
 */

#define MAX_FAILED_CONNS_END		20
#define MAX_FAILED_CONNS_RESTART	4
#define MAX_FAILED_CONNS_START		5

/* linked list of mappings between RADIUS attributes and LDAP attributes */
struct TLDAP_RADIUS {
	char*                 attr;
	char*                 radius_attr;
	struct TLDAP_RADIUS*  next;
};
typedef struct TLDAP_RADIUS TLDAP_RADIUS;

typedef struct ldap_conn {
	LDAP		*ld;
	char		bound;
	char		locked;
	int		failed_conns;
	pthread_mutex_t	mutex;
} LDAP_CONN;

typedef struct {
	char           *server;
	int             port;
	int             timelimit;
	struct timeval  net_timeout;
	struct timeval  timeout;
	int             debug;
	int             tls_mode;
	int		start_tls;
	int		num_conns;
	int		do_comp;
	int		default_allow;
	int		failed_conns;
	int		is_url;
	char           *login;
	char           *password;
	char           *filter;
	char           *basedn;
	char           *default_profile;
	char           *profile_attr;
	char           *access_attr;
	char           *passwd_hdr;
	char           *passwd_attr;
	char           *dictionary_mapping;
	char	       *groupname_attr;
	char	       *groupmemb_filt;
	char           *groupmemb_attr;
	char		**atts;
	TLDAP_RADIUS   *check_item_map;
	TLDAP_RADIUS   *reply_item_map;
	LDAP_CONN	*conns;
	int             ldap_debug; /* Debug flag for LDAP SDK */
	char		*xlat_name; /* name used to xlat */
}               ldap_instance;

static CONF_PARSER module_config[] = {
	{"server", PW_TYPE_STRING_PTR, offsetof(ldap_instance,server), NULL, "localhost"},
	{"port", PW_TYPE_INTEGER, offsetof(ldap_instance,port), NULL, "389"},
	/* wait forever on network activity */
	{"net_timeout", PW_TYPE_INTEGER, offsetof(ldap_instance,net_timeout.tv_sec), NULL, "10"},
	/* wait forever for search results */
	{"timeout", PW_TYPE_INTEGER, offsetof(ldap_instance,timeout.tv_sec), NULL, "20"},
	/* allow server unlimited time for search (server-side limit) */
	{"timelimit", PW_TYPE_INTEGER, offsetof(ldap_instance,timelimit), NULL, "20"},
	{"identity", PW_TYPE_STRING_PTR, offsetof(ldap_instance,login), NULL, ""},
	{"start_tls", PW_TYPE_BOOLEAN, offsetof(ldap_instance,start_tls), NULL, "no"},
	{"password", PW_TYPE_STRING_PTR, offsetof(ldap_instance,password), NULL, ""},
	{"basedn", PW_TYPE_STRING_PTR, offsetof(ldap_instance,basedn), NULL, "o=notexist"},
	{"filter", PW_TYPE_STRING_PTR, offsetof(ldap_instance,filter), NULL, "(uid=%u)"},
	{"default_profile", PW_TYPE_STRING_PTR, offsetof(ldap_instance,default_profile), NULL, NULL},
	{"profile_attribute", PW_TYPE_STRING_PTR, offsetof(ldap_instance,profile_attr), NULL, NULL},
	{"password_header", PW_TYPE_STRING_PTR, offsetof(ldap_instance,passwd_hdr), NULL, NULL},
	{"password_attribute", PW_TYPE_STRING_PTR, offsetof(ldap_instance,passwd_attr), NULL, NULL},
	/* LDAP attribute name that controls remote access */
	{"access_attr", PW_TYPE_STRING_PTR, offsetof(ldap_instance,access_attr), NULL, NULL},
	/* file with mapping between LDAP and RADIUS attributes */
	{"groupname_attribute", PW_TYPE_STRING_PTR, offsetof(ldap_instance,groupname_attr), NULL, "cn"},
	{"groupmembership_filter", PW_TYPE_STRING_PTR, offsetof(ldap_instance,groupmemb_filt), NULL, "(|(&(objectClass=GroupOfNames)(member=%{Ldap-UserDn}))(&(objectClass=GroupOfUniqueNames)(uniquemember=%{Ldap-UserDn})))"},
	{"groupmembership_attribute", PW_TYPE_STRING_PTR, offsetof(ldap_instance,groupmemb_attr), NULL, NULL},
	{"dictionary_mapping", PW_TYPE_STRING_PTR, offsetof(ldap_instance,dictionary_mapping), NULL, "${confdir}/ldap.attrmap"},
	{"ldap_debug", PW_TYPE_INTEGER, offsetof(ldap_instance,ldap_debug), NULL, "0x0000"},
	{"ldap_connections_number", PW_TYPE_INTEGER, offsetof(ldap_instance,num_conns), NULL, "5"},
	{"compare_check_items", PW_TYPE_BOOLEAN, offsetof(ldap_instance,do_comp), NULL, "no"},
	{"access_attr_used_for_allow", PW_TYPE_BOOLEAN, offsetof(ldap_instance,default_allow), NULL, "yes"},

	{NULL, -1, 0, NULL, NULL}
};

#define ld_valid                ld_options.ldo_valid
#define LDAP_VALID_SESSION      0x2
#define LDAP_VALID(ld)  ( (ld)->ld_valid == LDAP_VALID_SESSION )

#ifdef FIELDCPY
static void     fieldcpy(char *, char **);
#endif
static VALUE_PAIR *ldap_pairget(LDAP *, LDAPMessage *, TLDAP_RADIUS *,VALUE_PAIR **,char);
static int ldap_groupcmp(void *, REQUEST *, VALUE_PAIR *, VALUE_PAIR *, VALUE_PAIR *, VALUE_PAIR **);
static int ldap_xlat(void *,REQUEST *, char *, char *,int, RADIUS_ESCAPE_STRING);
static LDAP    *ldap_connect(void *instance, const char *, const char *, int, int *);
static int     read_mappings(ldap_instance* inst);

static inline int ldap_get_conn(LDAP_CONN *conns,LDAP_CONN **ret,void *instance)
{
	ldap_instance *inst = instance;
	register int i = 0;

	for(;i<inst->num_conns;i++){
		if (conns[i].locked == 0 && pthread_mutex_trylock(&(conns[i].mutex)) == 0){
			*ret = &conns[i];
			conns[i].locked = 1;
			DEBUG("ldap_get_conn: Got Id: %d",i);
			return i;
		}
	}

	return -1;
}
	
static inline void ldap_release_conn(int i, LDAP_CONN *conns)
{
	DEBUG("ldap_release_conn: Release Id: %d",i);
	conns[i].locked = 0;
	pthread_mutex_unlock(&(conns[i].mutex));
}

/*************************************************************************
 *
 *	Function: rlm_ldap_instantiate
 *
 *	Purpose: Uses section of radiusd config file passed as parameter
 *		 to create an instance of the module.
 *
 *************************************************************************/
static int 
ldap_instantiate(CONF_SECTION * conf, void **instance)
{
	ldap_instance  *inst;
	int i = 0;
	int atts_num = 0;
	int reply_map_num = 0;
	int check_map_num = 0;
	int att_map[3] = {0,0,0};
	TLDAP_RADIUS *pair;
	char *xlat_name;

	inst = rad_malloc(sizeof *inst);
	if (!inst) {
		return -1;
	}
	memset(inst, 0, sizeof(*inst));

	if (cf_section_parse(conf, inst, module_config) < 0) {
		free(inst);
		return -1;
	}

	if (inst->server == NULL) {
		radlog(L_ERR, "rlm_ldap: missing 'server' directive.");
		free(inst);
		return -1;
	}
	inst->is_url = 0;
#ifdef HAVE_LDAP_INITIALIZE
	if (ldap_is_ldap_url(inst->server)){
		inst->is_url = 1;
		inst->port = 0;
	}
#endif
 
	inst->timeout.tv_usec = 0;
	inst->net_timeout.tv_usec = 0;
	/* workaround for servers which support LDAPS but not START TLS */
	if(inst->port == LDAPS_PORT)
		inst->tls_mode = LDAP_OPT_X_TLS_HARD;
	else
		inst->tls_mode = 0;
	inst->reply_item_map = NULL;
	inst->check_item_map = NULL;
	inst->conns = NULL;
	inst->failed_conns = 0;

	paircompare_register(PW_LDAP_GROUP, PW_USER_NAME, ldap_groupcmp, inst);
	DEBUG("conns: %p",inst->conns);

	xlat_name = cf_section_name2(conf);
	if (xlat_name == NULL) {
		xlat_name = cf_section_name1(conf);
		rad_assert(xlat_name != NULL); /* or all hell breaks loose */
	}
	inst->xlat_name = strdup(xlat_name);
	xlat_register(xlat_name,ldap_xlat,inst);

	if (inst->num_conns <= 0){
		radlog(L_ERR, "rlm_ldap: Invalid ldap connections number passed.");
		free(inst);
		return -1;
	}
	inst->conns = (LDAP_CONN *)malloc(sizeof(LDAP_CONN)*inst->num_conns);
	if (inst->conns == NULL){
		radlog(L_ERR, "rlm_ldap: Could not allocate memory. Aborting.");
		free(inst);
		return -1;
	}
	for(;i<inst->num_conns;i++){
		inst->conns[i].bound = 0;
		inst->conns[i].locked = 0;
		inst->conns[i].failed_conns = 0;
		inst->conns[i].ld = NULL;
		pthread_mutex_init(&inst->conns[i].mutex, NULL);
	}	

	if (read_mappings(inst) != 0) {
		radlog(L_ERR, "rlm_ldap: Reading dictionary mappings from file %s failed",
		       inst->dictionary_mapping);
		radlog(L_ERR, "rlm_ldap: Proceeding with no mappings");
	}
	
	pair = inst->check_item_map;
	while(pair != NULL){
		atts_num++;
		pair = pair->next;
	}
	check_map_num = (atts_num - 1);
	pair = inst->reply_item_map;
	while(pair != NULL){
		atts_num++;
		pair = pair->next;
	}
	reply_map_num = (atts_num - 1);
	if (inst->profile_attr)
		atts_num++;
	if (inst->passwd_attr)
		atts_num++;
	if (inst->access_attr)
		atts_num++;
	inst->atts = (char **)malloc(sizeof(char *)*(atts_num + 1));
	if (inst->atts == NULL){
		radlog(L_ERR, "rlm_ldap: Could not allocate memory. Aborting.");
		free(inst);
		return -1;
	}
	pair = inst->check_item_map;
	for(i=0;i<atts_num;i++){
		if (i <= check_map_num ){
			inst->atts[i] = pair->attr;
			if (i == check_map_num)
				pair = inst->reply_item_map;
			else
				pair = pair->next;
		}
		else if (i <= reply_map_num){
			inst->atts[i] = pair->attr;
			pair = pair->next;
		}
		else{
			if (inst->profile_attr && !att_map[0]){
				inst->atts[i] = inst->profile_attr;
				att_map[0] = 1;
			}
			else if (inst->passwd_attr && !att_map[1]){
				inst->atts[i] = inst->passwd_attr;