nss-mymachines: do not allow overlong machine names

https://github.com/systemd/systemd/issues/2002

diff --git a/src/nss-mymachines/nss-mymachines.c b/src/nss-mymachines/nss-mymachines.c
index 969fa96..c98a959 100644 (file)
--- a/src/nss-mymachines/nss-mymachines.c
+++ b/src/nss-mymachines/nss-mymachines.c
@@ -416,6 +416,9 @@ enum nss_status _nss_mymachines_getpwnam_r(
         if (!e || e == p)
                 goto not_found;
 
+        if (e - p > HOST_NAME_MAX - 1) /* -1 for the last dash */
+                goto not_found;
+
         r = parse_uid(e + 1, &uid);
         if (r < 0)
                 goto not_found;
@@ -573,6 +576,9 @@ enum nss_status _nss_mymachines_getgrnam_r(
         if (!e || e == p)
                 goto not_found;
 
+        if (e - p > HOST_NAME_MAX - 1)  /* -1 for the last dash */
+                goto not_found;
+
         r = parse_gid(e + 1, &gid);
         if (r < 0)
                 goto not_found;