s3-winbindd: Add new module idmap_rfc2307

This module allows querying id mappings from LDAP servers as described
in RFC 2307. The LDAP records can be queried from an Active Directory
Server or from a stand-alone LDAP server.

Reviewed-by: Andrew Bartlett <abartlet@samba.org>

5 files changed, 886 insertions, 1 deletions

diff --git a/source3/Makefile.in b/source3/Makefile.in
index 576cce9bd8..7350ada9f8 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -2695,6 +2695,10 @@ bin/ad.@SHLIBEXT@: $(BINARY_PREREQS) winbindd/idmap_ad.o
 	@echo "Building plugin $@"
 	@$(SHLD_MODULE) winbindd/idmap_ad.o
 
+bin/rfc2307.@SHLIBEXT@: $(BINARY_PREREQS) winbindd/idmap_rfc2307.o
+	@echo "Building plugin $@"
+	@$(SHLD_MODULE) winbindd/idmap_rfc2307.o
+
 bin/hash.@SHLIBEXT@: $(BINARY_PREREQS) $(IDMAP_HASH_OBJ)
 	@echo "Building plugin $@"
 	@$(SHLD_MODULE) $(IDMAP_HASH_OBJ)
diff --git a/source3/configure.in b/source3/configure.in
index 8c3b36cc55..88c71d422f 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -6389,6 +6389,7 @@ SMB_MODULE(idmap_nss, winbindd/idmap_nss.o, "bin/nss.$SHLIBEXT", IDMAP)
 SMB_MODULE(idmap_rid, winbindd/idmap_rid.o, "bin/rid.$SHLIBEXT", IDMAP)
 SMB_MODULE(idmap_autorid, winbindd/idmap_autorid.o, "bin/autorid.$SHLIBEXT", IDMAP)
 SMB_MODULE(idmap_ad, winbindd/idmap_ad.o, "bin/ad.$SHLIBEXT", IDMAP)
+SMB_MODULE(idmap_rfc2307, winbindd/idmap_rfc2307.o, "bin/rfc2307.$SHLIBEXT", IDMAP)
 SMB_MODULE(idmap_hash, \$(IDMAP_HASH_OBJ), "bin/hash.$SHLIBEXT", IDMAP)
 SMB_SUBSYSTEM(IDMAP, winbindd/idmap.o)
 
diff --git a/source3/winbindd/idmap_rfc2307.c b/source3/winbindd/idmap_rfc2307.c
new file mode 100644
index 0000000000..2b7a593a15
--- /dev/null
+++ b/source3/winbindd/idmap_rfc2307.c
@@ -0,0 +1,870 @@
+/*
+ * Unix SMB/CIFS implementation.
+ *
+ * Id mapping using LDAP records as defined in RFC 2307
+ *
+ * The SID<->uid/gid mapping is performed in two steps: 1) Query the
+ * AD server for the name<->sid mapping. 2) Query an LDAP server
+ * according to RFC 2307 for the name<->uid/gid mapping.
+ *
+ * Copyright (C) Christof Schmitt 2012,2013
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "includes.h"
+#include "winbindd.h"
+#include "ads.h"
+#include "idmap.h"
+#include "smbldap.h"
+#include "nsswitch/winbind_client.h"
+#include "lib/winbind_util.h"
+
+/*
+ * Config and connection info per domain.
+ */
+struct idmap_rfc2307_context {
+	const char *bind_path_user;
+	const char *bind_path_group;
+	const char *ldap_domain;
+	bool cn_realm;
+	bool user_cn;
+	const char *realm;
+
+	/*
+	 * Pointer to ldap struct in ads or smbldap_state, has to be
+	 * updated after connecting to server
+	 */
+	LDAP *ldap;
+
+	/* Optional function to check connection to server */
+	NTSTATUS (*check_connection)(struct idmap_domain *dom);
+
+	/* Issue ldap query */
+	NTSTATUS (*search)(struct idmap_rfc2307_context *ctx,
+			   const char *bind_path, const char *expr,
+			   const char **attrs, LDAPMessage **res);
+
+	/* Access to LDAP in AD server */
+	ADS_STRUCT *ads;
+
+	/* Access to stand-alone LDAP server */
+	struct smbldap_state *smbldap_state;
+};
+
+/*
+ * backend functions for LDAP queries through ADS
+ */
+
+static NTSTATUS idmap_rfc2307_ads_check_connection(struct idmap_domain *dom)
+{
+	struct idmap_rfc2307_context *ctx;
+	const char *dom_name = dom->name;
+	ADS_STATUS status;
+
+	DEBUG(10, ("ad_idmap_cached_connection: called for domain '%s'\n",
+		   dom->name));
+
+	ctx = talloc_get_type(dom->private_data, struct idmap_rfc2307_context);
+	dom_name = ctx->ldap_domain ? ctx->ldap_domain : dom->name;
+
+	status = ads_idmap_cached_connection(&ctx->ads, dom_name);
+	if (ADS_ERR_OK(status)) {
+		ctx->ldap = ctx->ads->ldap.ld;
+		if (ctx->cn_realm) {
+			ctx->realm = ctx->ads->server.realm;
+		}
+	} else {
+		DEBUG(1, ("Could not connect to domain %s: %s\n", dom->name,
+			  ads_errstr(status)));
+	}
+
+	return ads_ntstatus(status);
+}
+
+static NTSTATUS idmap_rfc2307_ads_search(struct idmap_rfc2307_context *ctx,
+					 const char *bind_path,
+					 const char *expr,
+					 const char **attrs,
+					 LDAPMessage **result)
+{
+	ADS_STATUS status;
+
+	status = ads_do_search_retry(ctx->ads, bind_path,
+				     LDAP_SCOPE_SUBTREE, expr, attrs, result);
+	return ads_ntstatus(status);
+}
+
+static NTSTATUS idmap_rfc2307_init_ads(struct idmap_rfc2307_context *ctx,
+				       const char *cfg_opt)
+{
+	const char *ldap_domain;
+
+	ctx->search = idmap_rfc2307_ads_search;
+	ctx->check_connection = idmap_rfc2307_ads_check_connection;
+
+	ldap_domain = lp_parm_const_string(-1, cfg_opt, "ldap_domain",
+					      NULL);
+	if (ldap_domain) {
+		ctx->ldap_domain = talloc_strdup(ctx, ldap_domain);
+		if (ctx->ldap_domain == NULL) {
+			return NT_STATUS_NO_MEMORY;
+		}
+	}
+
+	return NT_STATUS_OK;
+}
+
+/*
+ * backend function for LDAP queries through stand-alone LDAP server
+ */
+
+static NTSTATUS idmap_rfc2307_ldap_search(struct idmap_rfc2307_context *ctx,
+					  const char *bind_path,
+					  const char *expr,
+					  const char **attrs,
+					  LDAPMessage **result)
+{
+	int ret;
+
+	ret = smbldap_search(ctx->smbldap_state, bind_path, LDAP_SCOPE_SUBTREE,
+			     expr, attrs, 0, result);
+	ctx->ldap = ctx->smbldap_state->ldap_struct;
+
+	if (ret == LDAP_SUCCESS) {
+		return NT_STATUS_OK;
+	}
+
+	return NT_STATUS_LDAP(ret);
+}
+
+static bool idmap_rfc2307_get_uint32(LDAP *ldap, LDAPMessage *entry,
+				     const char *field, uint32 *value)
+{
+	bool b;
+	char str[20];
+
+	b = smbldap_get_single_attribute(ldap, entry, field, str, sizeof(str));
+
+	if (b) {
+		*value = atoi(str);
+	}
+
+	return b;
+}
+
+static NTSTATUS idmap_rfc2307_init_ldap(struct idmap_rfc2307_context *ctx,
+					struct idmap_domain *dom,
+					const char *config_option)
+{
+	NTSTATUS ret;
+	char *url;
+	char *secret = NULL;
+	const char *ldap_url, *user_dn, *ldap_realm;
+	TALLOC_CTX *mem_ctx = ctx;
+
+	ldap_url = lp_parm_const_string(-1, config_option, "ldap_url", NULL);
+	if (!ldap_url) {
+		DEBUG(1, ("ERROR: missing idmap ldap url\n"));
+		return NT_STATUS_UNSUCCESSFUL;
+	}
+
+	url = talloc_strdup(talloc_tos(), ldap_url);
+
+	user_dn = lp_parm_const_string(-1, config_option, "ldap_user_dn", NULL);
+	if (user_dn) {
+		secret = idmap_fetch_secret("ldap", dom->name, user_dn);
+		if (!secret) {
+			ret = NT_STATUS_ACCESS_DENIED;
+			goto done;
+		}
+	}
+
+	/* assume anonymous if we don't have a specified user */
+	ret = smbldap_init(mem_ctx, winbind_event_context(), url,
+			   (user_dn == NULL), user_dn, secret,
+			   &ctx->smbldap_state);
+	SAFE_FREE(secret);
+	if (!NT_STATUS_IS_OK(ret)) {
+		DEBUG(1, ("ERROR: smbldap_init (%s) failed!\n", url));
+		goto done;
+	}
+
+	ctx->search = idmap_rfc2307_ldap_search;
+
+	if (ctx->cn_realm) {
+		ldap_realm = lp_parm_const_string(-1, config_option,
+						  "ldap_realm", NULL);
+		if (!ldap_realm) {
+			DEBUG(1, ("ERROR: cn_realm set, "
+				  "but ldap_realm is missing\n"));
+			ret = NT_STATUS_UNSUCCESSFUL;
+			goto done;
+		}
+		ctx->realm = talloc_strdup(mem_ctx, ldap_realm);
+		if (!ctx->realm) {
+			ret = NT_STATUS_NO_MEMORY;
+		}
+	}
+
+done:
+	talloc_free(url);
+	return ret;
+}
+
+/*
+ * common code for stand-alone LDAP and ADS
+ */
+
+static void idmap_rfc2307_map_sid_results(struct idmap_rfc2307_context *ctx,
+					  TALLOC_CTX *mem_ctx,
+					  struct id_map **ids,
+					  LDAPMessage *result,
+					  const char *dom_name,
+					  const char **attrs, int type)
+{
+	int count, i;
+	LDAPMessage *entry;
+
+	count = ldap_count_entries(ctx->ldap, result);
+
+	for (i = 0; i < count; i++) {
+		char *name;
+		enum lsa_SidType lsa_type;
+		struct id_map *map;
+		uint32_t id;
+		bool b;
+
+		if (i == 0) {
+			entry = ldap_first_entry(ctx->ldap, result);
+		} else {
+			entry = ldap_next_entry(ctx->ldap, result);
+		}
+		if (!entry) {
+			DEBUG(2, ("Unable to fetch entry.\n"));
+			break;
+		}
+
+		name = smbldap_talloc_single_attribute(ctx->ldap, entry,
+						       attrs[0], mem_ctx);
+		if (!name) {
+			DEBUG(1, ("Could not get user name\n"));
+			continue;
+		}
+
+		b = idmap_rfc2307_get_uint32(ctx->ldap, entry, attrs[1], &id);
+		if (!b) {
+			DEBUG(1, ("Could not pull id for record %s\n", name));
+			continue;
+		}
+
+		map = idmap_find_map_by_id(ids, type, id);
+		if (!map) {
+			DEBUG(1, ("Could not find id %d, name %s\n", id, name));
+			continue;
+		}
+
+		if (ctx->cn_realm) {
+			/* Strip @realm from user or group name */
+			char *delim;
+
+			delim = strchr(name, '@');
+			if (delim) {
+				*delim = '\0';
+			}
+		}
+
+		/* by default calls to winbindd are disabled
+		   the following call will not recurse so this is safe */
+		(void)winbind_on();
+		/* Lookup name from PDC using lsa_lookup_names() */
+		b = winbind_lookup_name(dom_name, name, map->sid, &lsa_type);
+		(void)winbind_off();
+
+		if (!b) {
+			DEBUG(1, ("SID lookup failed for id %d, %s\n",
+				  id, name));
+			continue;
+		}
+
+		if (type == ID_TYPE_UID && lsa_type != SID_NAME_USER) {
+			DEBUG(1, ("Wrong type %d for user name %s\n",
+				  type, name));
+			continue;
+		}
+
+		if (type == ID_TYPE_GID && lsa_type != SID_NAME_DOM_GRP &&
+		    lsa_type != SID_NAME_ALIAS &&
+		    lsa_type != SID_NAME_WKN_GRP) {
+			DEBUG(1, ("Wrong type %d for group name %s\n",
+				  type, name));
+			continue;
+		}
+
+		map->status = ID_MAPPED;
+	}
+}
+
+/*
+ * Map unixids to names and then to sids.
+ */
+static NTSTATUS idmap_rfc2307_unixids_to_sids(struct idmap_domain *dom,
+					      struct id_map **ids)
+{
+	struct idmap_rfc2307_context *ctx;
+	char *fltr_usr = NULL, *fltr_grp = NULL;
+	TALLOC_CTX *mem_ctx;
+	int cnt_usr = 0, cnt_grp = 0, idx = 0, bidx = 0;
+	LDAPMessage *result = NULL;
+	NTSTATUS ret;
+
+	ctx = talloc_get_type(dom->private_data, struct idmap_rfc2307_context);
+	mem_ctx = talloc_new(ctx);
+	if (!mem_ctx) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if (ctx->check_connection) {
+		ret = ctx->check_connection(dom);
+		if (!NT_STATUS_IS_OK(ret)) {
+			goto out;
+		}
+	}
+
+again:
+	bidx = idx;
+
+	if (!fltr_usr) {
+		/* prepare new user query, see getpwuid() in RFC2307 */
+		fltr_usr = talloc_asprintf(mem_ctx,
+					     "(&(objectClass=posixAccount)(|");
+	}
+
+	if (!fltr_grp) {
+		/* prepare new group query, see getgrgid() in RFC2307 */
+		fltr_grp = talloc_asprintf(mem_ctx,
+					     "(&(objectClass=posixGroup)(|");
+	}
+
+	if (!fltr_usr || !fltr_grp) {
+		ret = NT_STATUS_NO_MEMORY;
+		goto out;
+	}
+
+	while (cnt_usr < IDMAP_LDAP_MAX_IDS &&
+	       cnt_grp < IDMAP_LDAP_MAX_IDS && ids[idx]) {
+
+		switch (ids[idx]->xid.type) {
+		case ID_TYPE_UID:
+			fltr_usr = talloc_asprintf_append_buffer(fltr_usr,
+					"(uidNumber=%d)", ids[idx]->xid.id);
+			cnt_usr++;
+			break;
+		case ID_TYPE_GID:
+			fltr_grp = talloc_asprintf_append_buffer(fltr_grp,
+					"(gidNumber=%d))", ids[idx]->xid.id);
+			cnt_grp++;
+			break;
+		default:
+			DEBUG(3, ("Error: unknown ID type %d\n",
+				  ids[idx]->xid.type));
+			ret = NT_STATUS_UNSUCCESSFUL;
+			goto out;
+		}
+
+		if (!fltr_usr || !fltr_grp) {
+			ret = NT_STATUS_NO_MEMORY;
+			goto out;
+		}
+
+		idx++;
+	}
+
+	if (cnt_usr == IDMAP_LDAP_MAX_IDS || (cnt_usr != 0 && !ids[idx])) {
+		const char *attrs[] = { NULL, /* uid or cn */
+					"uidNumber",
+					NULL };
+
+		fltr_usr = talloc_strdup_append(fltr_usr, "))");
+		if (!fltr_usr) {
+			ret = NT_STATUS_NO_MEMORY;
+			goto out;
+		}
+
+		attrs[0] = ctx->user_cn ? "cn" : "uid";
+		ret = ctx->search(ctx, ctx->bind_path_user, fltr_usr, attrs,
+				  &result);
+		if (!NT_STATUS_IS_OK(ret)) {
+			goto out;
+		}
+
+		idmap_rfc2307_map_sid_results(ctx, mem_ctx, &ids[bidx], result,
+					      dom->name, attrs, ID_TYPE_UID);
+		cnt_usr = 0;
+		TALLOC_FREE(fltr_usr);
+	}
+
+	if (cnt_grp == IDMAP_LDAP_MAX_IDS || (cnt_grp != 0 && !ids[idx])) {
+		const char *attrs[] = { "cn", "gidNumber", NULL };
+
+		fltr_grp = talloc_strdup_append(fltr_grp, "))");
+		if (!fltr_grp) {
+			ret = NT_STATUS_NO_MEMORY;
+			goto out;
+		}
+		ret = ctx->search(ctx, ctx->bind_path_group, fltr_grp, attrs,
+				  &result);
+		if (!NT_STATUS_IS_OK(ret)) {
+			goto out;
+		}
+
+		idmap_rfc2307_map_sid_results(ctx, mem_ctx, &ids[bidx], result,
+					      dom->name, attrs, ID_TYPE_GID);
+		cnt_grp = 0;
+		TALLOC_FREE(fltr_grp);
+	}
+
+	if (ids[idx]) {
+		goto again;
+	}
+
+	ret = NT_STATUS_OK;
+
+out:
+	talloc_free(mem_ctx);
+	return ret;
+}
+
+struct idmap_rfc2307_map {
+	struct id_map *map;
+	const char *name;
+	enum id_type type;
+};
+
+/*
+ * Lookup names for SIDS and store the data in the local mapping
+ * array.
+ */
+static NTSTATUS idmap_rfc_2307_sids_to_names(TALLOC_CTX *mem_ctx,
+					     struct id_map **ids,
+					     struct idmap_rfc2307_map *maps,
+					     struct idmap_rfc2307_context *ctx)
+{
+	int i;
+
+	for (i = 0; ids[i]; i++) {
+		const char *domain, *name;
+		enum lsa_SidType lsa_type;
+		struct id_map *id = ids[i];
+		struct idmap_rfc2307_map *map = &maps[i];
+		bool b;
+
+		/* by default calls to winbindd are disabled
+		   the following call will not recurse so this is safe */
+		(void)winbind_on();
+		b = winbind_lookup_sid(mem_ctx, ids[i]->sid, &domain, &name,
+				       &lsa_type);
+		(void)winbind_off();
+
+		if (!b) {
+			DEBUG(1, ("Lookup sid %s failed.\n",
+				  sid_string_dbg(ids[i]->sid)));
+			continue;
+		}
+
+		switch(lsa_type) {
+		case SID_NAME_USER:
+			id->xid.type = map->type = ID_TYPE_UID;
+			if (ctx->user_cn && ctx->cn_realm) {
+				name = talloc_asprintf(mem_ctx, "%s@%s",
+						       name, ctx->realm);
+			}
+			id->xid.type = map->type = ID_TYPE_UID;
+			break;
+
+		case SID_NAME_DOM_GRP:
+		case SID_NAME_ALIAS:
+		case SID_NAME_WKN_GRP:
+			if (ctx->cn_realm) {
+				name = talloc_asprintf(mem_ctx, "%s@%s",
+						       name, ctx->realm);
+			}
+			id->xid.type = map->type = ID_TYPE_GID;
+			break;
+
+		default:
+			DEBUG(1, ("Unknown lsa type %d for sid %s\n",
+				  lsa_type, sid_string_dbg(id->sid)));
+			id->status = ID_UNMAPPED;
+			continue;
+		}
+
+		map->map = id;
+		id->status = ID_UNKNOWN;
+		map->name = strupper_talloc(mem_ctx, name);
+
+		if (!map->name) {
+			return NT_STATUS_NO_MEMORY;
+		}
+	}
+
+	return NT_STATUS_OK;
+}
+
+/*
+ * Find id_map entry by looking up the name in the internal
+ * mapping array.
+ */
+static struct id_map* idmap_rfc2307_find_map(struct idmap_rfc2307_map *maps,
+					     enum id_type type,
+					     const char *name)
+{
+	int i;
+
+	DEBUG(10, ("Looking for name %s, type %d\n", name, type));
+
+	for (i = 0; i < IDMAP_LDAP_MAX_IDS; i++) {
+		if (maps[i].map == NULL) { /* end of the run */
+			return NULL;
+		}
+		DEBUG(10, ("Entry %d: name %s, type %d\n",
+			   i, maps[i].name, maps[i].type));
+		if (type == maps[i].type && strcmp(name, maps[i].name) == 0) {
+			return maps[i].map;
+		}
+	}
+
+	return NULL;
+}
+
+static void idmap_rfc2307_map_xid_results(struct idmap_rfc2307_context *ctx,
+					  TALLOC_CTX *mem_ctx,
+					  struct id_map **ids,
+					  struct idmap_rfc2307_map *maps,
+					  LDAPMessage *result,
+					  struct idmap_domain *dom,
+					  const char **attrs, enum id_type type)
+{
+	int count, i;
+	LDAPMessage *entry;
+
+	count = ldap_count_entries(ctx->ldap, result);
+
+	for (i = 0; i < count; i++) {
+		uint32_t id;
+		char *name;
+		bool b;
+		struct id_map *id_map;
+
+		if (i == 0) {
+			entry = ldap_first_entry(ctx->ldap, result);
+		} else {
+			entry = ldap_next_entry(ctx->ldap, result);
+		}
+		if (!entry) {
+			DEBUG(2, ("Unable to fetch entry.\n"));
+			break;
+		}
+
+		name = smbldap_talloc_single_attribute(ctx->ldap, entry,
+						       attrs[0], mem_ctx);
+		if (!name) {
+			DEBUG(1, ("Could not get user name\n"));
+			continue;
+		}
+
+		b = idmap_rfc2307_get_uint32(ctx->ldap, entry, attrs[1], &id);
+		if (!b) {
+			DEBUG(5, ("Could not pull id for record %s\n", name));
+			continue;
+		}
+
+		if (!idmap_unix_id_is_in_range(id, dom)) {
+			DEBUG(5, ("Requested id (%u) out of range (%u - %u).\n",
+				  id, dom->low_id, dom->high_id));
+			continue;
+		}
+
+		if (!strupper_m(name)) {
+			DEBUG(5, ("Could not convert %s to uppercase\n", name));
+			continue;
+		}
+		id_map = idmap_rfc2307_find_map(maps, type, name);
+		if (!id_map) {
+			DEBUG(0, ("Could not find mapping entry for name %s\n",
+				  name));
+			continue;
+		}
+
+		id_map->xid.id = id;
+		id_map->status = ID_MAPPED;
+	}
+}
+
+/*
+ * Map sids to names and then to unixids.
+ */
+static NTSTATUS idmap_rfc2307_sids_to_unixids(struct idmap_domain *dom,
+					      struct id_map **ids)
+{
+	struct idmap_rfc2307_context *ctx;
+	TALLOC_CTX *mem_ctx;
+	struct idmap_rfc2307_map *int_maps;
+	int cnt_usr = 0, cnt_grp = 0, idx = 0, bidx = 0;
+	char *fltr_usr = NULL, *fltr_grp = NULL;
+	NTSTATUS ret;
+	int i;
+
+	ctx = talloc_get_type(dom->private_data, struct idmap_rfc2307_context);
+	mem_ctx = talloc_new(talloc_tos());
+	if (!mem_ctx) {
+		return NT_STATUS_NO_MEMORY;
+	}
+
+	if (ctx->check_connection) {
+		ret = ctx->check_connection(dom);
+		if (!NT_STATUS_IS_OK(ret)) {
+			goto out;
+		}
+	}
+
+	for (i = 0; ids[i]; i++);
+	int_maps = talloc_zero_array(mem_ctx, struct idmap_rfc2307_map, i);
+	if (!int_maps) {
+		ret = NT_STATUS_NO_MEMORY;
+		goto out;
+	}
+
+	ret = idmap_rfc_2307_sids_to_names(mem_ctx, ids, int_maps, ctx);
+	if (!NT_STATUS_IS_OK(ret)) {
+		goto out;
+	}
+
+again:
+	if (!fltr_usr) {
+		/* prepare new user query, see getpwuid() in RFC2307 */
+		fltr_usr = talloc_asprintf(mem_ctx,
+					     "(&(objectClass=posixAccount)(|");
+	}
+
+	if (!fltr_grp) {
+		/* prepare new group query, see getgrgid() in RFC2307 */
+		fltr_grp = talloc_asprintf(mem_ctx,
+					     "(&(objectClass=posixGroup)(|");
+	}
+
+	if (!fltr_usr || !fltr_grp) {
+		ret = NT_STATUS_NO_MEMORY;
+		goto out;
+	}
+
+	while (cnt_usr < IDMAP_LDAP_MAX_IDS &&
+	       cnt_grp < IDMAP_LDAP_MAX_IDS && ids[idx]) {
+		struct id_map *id = ids[idx];
+		struct idmap_rfc2307_map *map = &int_maps[idx];
+
+		switch(id->xid.type) {
+		case ID_TYPE_UID:
+			fltr_usr = talloc_asprintf_append_buffer(fltr_usr,
+				     "(%s=%s)", (ctx->user_cn ? "cn" : "uid"),
+				      map->name);
+			cnt_usr++;
+			break;
+
+		case ID_TYPE_GID:
+			fltr_grp = talloc_asprintf_append_buffer(fltr_grp,
+					 "(cn=%s)", map->name);
+			cnt_grp++;
+			break;
+
+		default:
+			DEBUG(10, ("Nothing to do for SID %s, "
+				   "previous name lookup failed\n",
+				   sid_string_dbg(map->map->sid)));
+		}
+
+		if (!fltr_usr || !fltr_grp) {
+			ret = NT_STATUS_NO_MEMORY;
+			goto out;
+		}
+
+		idx++;
+	}
+
+	if (cnt_usr == IDMAP_LDAP_MAX_IDS || (cnt_usr != 0 && !ids[idx])) {
+		const char *attrs[] = { NULL, /* uid or cn */
+					"uidNumber",
+					NULL };
+		LDAPMessage *result;
+
+		fltr_usr = talloc_strdup_append(fltr_usr, "))");
+		if (!fltr_usr) {
+			ret = NT_STATUS_NO_MEMORY;
+			goto out;
+		}
+
+		attrs[0] = ctx->user_cn ? "cn" : "uid";
+		ret = ctx->search(ctx, ctx->bind_path_user, fltr_usr, attrs,
+				  &result);
+		if (!NT_STATUS_IS_OK(ret)) {
+			goto out;
+		}
+
+		idmap_rfc2307_map_xid_results(ctx, mem_ctx, &ids[bidx],
+					      int_maps, result, dom,
+					      attrs, ID_TYPE_UID);
+
+		cnt_usr = 0;
+		TALLOC_FREE(fltr_usr);
+	}
+
+	if (cnt_grp == IDMAP_LDAP_MAX_IDS || (cnt_grp != 0 && !ids[idx])) {
+		const char *attrs[] = {"cn", "gidNumber", NULL };
+		LDAPMessage *result;
+
+		fltr_grp = talloc_strdup_append(fltr_grp, "))");
+		if (!fltr_grp) {
+			ret = NT_STATUS_NO_MEMORY;
+			goto out;
+		}
+
+		ret = ctx->search(ctx, ctx->bind_path_group, fltr_grp, attrs,
+				  &result);
+		if (!NT_STATUS_IS_OK(ret)) {
+			goto out;
+		}
+
+		idmap_rfc2307_map_xid_results(ctx, mem_ctx, &ids[bidx],
+					      int_maps, result, dom,
+					      attrs, ID_TYPE_GID);
+		cnt_grp = 0;
+		TALLOC_FREE(fltr_grp);
+	}
+
+	if (ids[idx]) {
+		goto again;
+	}
+
+	ret = NT_STATUS_OK;
+
+out:
+	talloc_free(mem_ctx);
+	return ret;
+}
+
+static int idmap_rfc2307_context_destructor(struct idmap_rfc2307_context *ctx)
+{
+	if (ctx->ads != NULL) {
+		/* we own this ADS_STRUCT so make sure it goes away */
+		ctx->ads->is_mine = True;
+		ads_destroy( &ctx->ads );
+		ctx->ads = NULL;
+	}
+
+	if (ctx->smbldap_state != NULL) {
+		smbldap_free_struct(&ctx->smbldap_state);
+	}
+
+	return 0;
+}
+
+static NTSTATUS idmap_rfc2307_initialize(struct idmap_domain *domain)
+{
+	struct idmap_rfc2307_context *ctx;
+	char *cfg_opt;
+	const char *bind_path_user, *bind_path_group, *ldap_server;
+	NTSTATUS status;
+
+	ctx = talloc_zero(domain, struct idmap_rfc2307_context);
+	if (ctx == NULL) {
+		return NT_STATUS_NO_MEMORY;
+	}
+	talloc_set_destructor(ctx, idmap_rfc2307_context_destructor);
+
+	cfg_opt = talloc_asprintf(ctx, "idmap config %s", domain->name);
+	if (cfg_opt == NULL) {
+		status = NT_STATUS_NO_MEMORY;
+		goto err;
+	}
+
+	bind_path_user = lp_parm_const_string(-1, cfg_opt, "bind_path_user",
+					      NULL);
+	if (bind_path_user) {
+		ctx->bind_path_user = talloc_strdup(ctx, bind_path_user);
+		if (ctx->bind_path_user == NULL) {
+			status = NT_STATUS_NO_MEMORY;
+			goto err;
+		}
+	} else {
+		status = NT_STATUS_INVALID_PARAMETER;
+		goto err;
+	}
+
+	bind_path_group = lp_parm_const_string(-1, cfg_opt, "bind_path_group",
+					       NULL);
+	if (bind_path_group) {
+		ctx->bind_path_group = talloc_strdup(ctx, bind_path_group);
+		if (ctx->bind_path_group == NULL) {
+			status = NT_STATUS_NO_MEMORY;
+			goto err;
+		}
+	} else {
+		status = NT_STATUS_INVALID_PARAMETER;
+		goto err;
+	}
+
+	ldap_server = lp_parm_const_string(-1, cfg_opt, "ldap_server", NULL);
+	if (!ldap_server) {
+		status = NT_STATUS_INVALID_PARAMETER;
+		goto err;
+	}
+
+	if (strcmp(ldap_server, "stand-alone") == 0) {
+		status = idmap_rfc2307_init_ldap(ctx, domain, cfg_opt);
+
+	} else if (strcmp(ldap_server, "ad") == 0) {
+		status = idmap_rfc2307_init_ads(ctx, cfg_opt);
+
+	} else {
+		status = NT_STATUS_INVALID_PARAMETER;
+	}
+
+	if (!NT_STATUS_IS_OK(status)) {
+		goto err;
+	}
+
+	ctx->cn_realm = lp_parm_bool(-1, cfg_opt, "cn_realm", false);
+	ctx->user_cn = lp_parm_bool(-1, cfg_opt, "user_cn", false);
+
+	domain->private_data = ctx;
+	talloc_free(cfg_opt);
+	return NT_STATUS_OK;
+
+err:
+	talloc_free(cfg_opt);
+	talloc_free(ctx);
+	return status;
+}
+
+static struct idmap_methods rfc2307_methods = {
+	.init = idmap_rfc2307_initialize,
+	.unixids_to_sids = idmap_rfc2307_unixids_to_sids,
+	.sids_to_unixids = idmap_rfc2307_sids_to_unixids,
+};
+
+NTSTATUS idmap_rfc2307_init(void)
+{
+	return smb_register_idmap(SMB_IDMAP_INTERFACE_VERSION, "rfc2307",
+				  &rfc2307_methods);
+}
diff --git a/source3/winbindd/wscript_build b/source3/winbindd/wscript_build
index 7e807272a9..aacd859680 100644
--- a/source3/winbindd/wscript_build
+++ b/source3/winbindd/wscript_build
@@ -1,6 +1,7 @@
 #!/usr/bin/env python
 
 IDMAP_AD_SRC = '''idmap_ad.c'''
+IDMAP_RFC2307_SRC = '''idmap_rfc2307.c'''
 IDMAP_RID_SRC = '''idmap_rid.c'''
 IDMAP_PASSDB_SRC = '''idmap_passdb.c'''
 IDMAP_LDAP_SRC = '''idmap_ldap.c'''
@@ -43,6 +44,15 @@ bld.SAMBA3_MODULE('idmap_ad',
                  internal_module=bld.SAMBA3_IS_STATIC_MODULE('idmap_ad'),
                  enabled=bld.SAMBA3_IS_ENABLED_MODULE('idmap_ad') and bld.CONFIG_SET("HAVE_LDAP"))
 
+bld.SAMBA3_MODULE('idmap_rfc2307',
+                 subsystem='idmap',
+                 allow_undefined_symbols=True,
+                 source=IDMAP_RFC2307_SRC,
+                 init_function='',
+                 deps='ads',
+                 internal_module=bld.SAMBA3_IS_STATIC_MODULE('idmap_rfc2307'),
+                 enabled=bld.SAMBA3_IS_ENABLED_MODULE('idmap_rfc2307') and bld.CONFIG_SET("HAVE_LDAP"))
+
 bld.SAMBA3_MODULE('idmap_rid',
                  subsystem='idmap',
                  allow_undefined_symbols=True,
diff --git a/source3/wscript b/source3/wscript
index 42f532d9db..2cf71f0068 100644
--- a/source3/wscript
+++ b/source3/wscript
@@ -1688,7 +1688,7 @@ main() {
 				      vfs_commit
                                       vfs_crossrename vfs_linux_xfs_sgid
                                       vfs_time_audit idmap_autorid idmap_tdb2
-                                      idmap_rid idmap_hash'''))
+                                      idmap_rid idmap_hash idmap_rfc2307'''))
 
     if Options.options.developer:
         default_static_modules.extend(TO_LIST('charset_weird'))