Fall back to cn if gecos is not available

We were not fully compliant with section 5.3 of RFC 2307 which
states:

   An account's GECOS field is preferably determined by a value of the
   gecos attribute. If no gecos attribute exists, the value of the cn
   attribute MUST be used. (The existence of the gecos attribute allows
   information embedded in the GECOS field, such as a user's telephone
   number, to be returned to the client without overloading the cn
   attribute. It also accommodates directories where the common name
   does not contain the user's full name.)

1 files changed, 9 insertions, 0 deletions

diff --git a/src/providers/ldap/sdap_async_accounts.c b/src/providers/ldap/sdap_async_accounts.c
index 54416bb1..29a0f9f6 100644
--- a/src/providers/ldap/sdap_async_accounts.c
+++ b/src/providers/ldap/sdap_async_accounts.c
@@ -91,6 +91,15 @@ static int sdap_save_user(TALLOC_CTX *memctx,
     if (el->num_values == 0) gecos = NULL;
     else gecos = (const char *)el->values[0].data;
 
+    if (!gecos) {
+        /* Fall back to the user's full name */
+        ret = sysdb_attrs_get_el(
+                attrs,
+                opts->user_map[SDAP_AT_USER_FULLNAME].sys_name, &el);
+        if (ret) goto fail;
+        if (el->num_values > 0) gecos = (const char *)el->values[0].data;
+    }
+
     ret = sysdb_attrs_get_el(attrs,
                              opts->user_map[SDAP_AT_USER_HOME].sys_name, &el);
     if (ret) goto fail;