s3: shortcut gid_to_sid when "ldapsam:trusted = yes"

The normal gid_to_sid behaviour is to call sys_getgrgid()
to get the name for the given gid and then call the
getsamgrnam passdb method for the resulting name.

In the ldapsam:trusted case we can reduce the gid_to_sid
operation to one simple search for the gidNumber attribute
and only get the sambaSID attribute from the correspoinding
LDAP object. This reduces the number of ldap roundtrips
for this operation.

metze
(similar to commit 0fb99386d41241f62312d4bb535976344e5d6492)
(cherry picked from commit 479087716f50e8a1961163750b1d651dcd23dfc2)

1 files changed, 72 insertions, 0 deletions

diff --git a/source3/passdb/pdb_ldap.c b/source3/passdb/pdb_ldap.c
index 66db0eba02a..d9894c1f61b 100644
--- a/source3/passdb/pdb_ldap.c
+++ b/source3/passdb/pdb_ldap.c
@@ -5044,6 +5044,77 @@ static bool ldapsam_uid_to_sid(struct pdb_methods *methods, uid_t uid,
 	return ret;
 }
 
+/**
+ * Find the SID for a gid.
+ * This is shortcut is only used if ldapsam:trusted is set to true.
+ */
+static bool ldapsam_gid_to_sid(struct pdb_methods *methods, gid_t gid,
+			       DOM_SID *sid)
+{
+	struct ldapsam_privates *priv =
+		(struct ldapsam_privates *)methods->private_data;
+	char *filter;
+	const char *attrs[] = { "sambaSID", NULL };
+	LDAPMessage *result = NULL;
+	LDAPMessage *entry = NULL;
+	bool ret = false;
+	char *group_sid_string;
+	DOM_SID *group_sid;
+	int rc;
+	TALLOC_CTX *tmp_ctx = talloc_stackframe();
+
+	filter = talloc_asprintf(tmp_ctx,
+				 "(&(gidNumber=%u)"
+				 "(objectClass=%s))",
+				 (unsigned int)gid,
+				 LDAP_OBJ_GROUPMAP);
+	if (filter == NULL) {
+		DEBUG(3, ("talloc_asprintf failed\n"));
+		goto done;
+	}
+
+	rc = smbldap_search_suffix(priv->smbldap_state, filter, attrs, &result);
+	if (rc != LDAP_SUCCESS) {
+		goto done;
+	}
+	talloc_autofree_ldapmsg(tmp_ctx, result);
+
+	if (ldap_count_entries(priv2ld(priv), result) != 1) {
+		DEBUG(3, ("ERROR: Got %d entries for gid %u, expected one\n",
+			   ldap_count_entries(priv2ld(priv), result),
+			   (unsigned int)gid));
+		goto done;
+	}
+
+	entry = ldap_first_entry(priv2ld(priv), result);
+
+	group_sid_string = smbldap_talloc_single_attribute(priv2ld(priv), entry,
+							  "sambaSID", tmp_ctx);
+	if (group_sid_string == NULL) {
+		DEBUG(1, ("Could not find sambaSID in object '%s'\n",
+			  smbldap_talloc_dn(tmp_ctx, priv2ld(priv), entry)));
+		goto done;
+	}
+
+	group_sid = string_sid_talloc(tmp_ctx, group_sid_string);
+	if (group_sid == NULL) {
+		DEBUG(3, ("Error calling sid_string_talloc for sid '%s'\n",
+			  group_sid_string));
+		goto done;
+	}
+
+	sid_copy(sid, group_sid);
+
+	store_gid_sid_cache(sid, gid);
+	idmap_cache_set_sid2gid(sid, gid);
+
+	ret = true;
+
+ done:
+	TALLOC_FREE(tmp_ctx);
+	return ret;
+}
+
 
 /*
  * The following functions is called only if
@@ -6405,6 +6476,7 @@ NTSTATUS pdb_init_ldapsam(struct pdb_methods **pdb_method, const char *location)
 		(*pdb_method)->lookup_rids = ldapsam_lookup_rids;
 		(*pdb_method)->sid_to_id = ldapsam_sid_to_id;
 		(*pdb_method)->uid_to_sid = ldapsam_uid_to_sid;
+		(*pdb_method)->gid_to_sid = ldapsam_gid_to_sid;
 
 		if (lp_parm_bool(-1, "ldapsam", "editposix", False)) {
 			(*pdb_method)->create_user = ldapsam_create_user;