2 files changed, 17 insertions, 1 deletions
diff --git a/src/lib/idmap/sss_idmap.c b/src/lib/idmap/sss_idmap.c
index c589bd45..d7254e3e 100644
--- a/src/lib/idmap/sss_idmap.c
+++ b/src/lib/idmap/sss_idmap.c
@@ -280,6 +280,15 @@ fail:
     return IDMAP_OUT_OF_MEMORY;
 }
 
+static bool sss_idmap_sid_is_builtin(const char *sid)
+{
+    if (strncmp(sid, "S-1-5-32-", 9) == 0) {
+        return true;
+    }
+
+    return false;
+}
+
 enum idmap_error_code sss_idmap_sid_to_unix(struct sss_idmap_ctx *ctx,
                                             const char *sid,
                                             uint32_t *id)
@@ -293,6 +302,10 @@ enum idmap_error_code sss_idmap_sid_to_unix(struct sss_idmap_ctx *ctx,
 
     idmap_domain_info = ctx->idmap_domain_info;
 
+    if (sid && sss_idmap_sid_is_builtin(sid)) {
+        return IDMAP_BUILTIN_SID;
+    }
+
     while (idmap_domain_info != NULL) {
         dom_len = strlen(idmap_domain_info->sid);
         if (strlen(sid) > dom_len && sid[dom_len] == '-' &&
diff --git a/src/lib/idmap/sss_idmap.h b/src/lib/idmap/sss_idmap.h
index 6b7cbe50..22a4d548 100644
--- a/src/lib/idmap/sss_idmap.h
+++ b/src/lib/idmap/sss_idmap.h
@@ -68,7 +68,10 @@ enum idmap_error_code {
     IDMAP_SID_UNKNOWN,
 
     /** The provided UID or GID could not be mapped */
-    IDMAP_NO_RANGE
+    IDMAP_NO_RANGE,
+
+    /** The provided SID is a built-in one */
+    IDMAP_BUILTIN_SID
 };
 
 /**