From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Fri, 18 Apr 2025 12:29:21 +0000 (-0300)
Subject: locale: Fix UB on add_locale_uint32_array
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d5c20a5be6835a73f43ec09ee5d3e50379874b14;p=thirdparty%2Fglibc.git

locale: Fix UB on add_locale_uint32_array

The ubsan triggers:

UBSAN: Undefined behaviour in programs/locfile.c:644:3 null pointer passed as argument 2, nonnull attribute declared at unknown:0:0

The obstack_grow is only required if there is extra elements to be
inserted (n_elems > 0).
---

diff --git a/locale/programs/locfile.c b/locale/programs/locfile.c
index b54fcbbceb..7907c949ea 100644
--- a/locale/programs/locfile.c
+++ b/locale/programs/locfile.c
@@ -641,6 +641,8 @@ add_locale_uint32_array (struct locale_file *file,
 {
   align_locale_data (file, LOCFILE_ALIGN);
   record_offset (file);
+  if (n_elems == 0)
+    return;
   obstack_grow (&file->data, data, n_elems * sizeof (uint32_t));
   maybe_swap_uint32_obstack (&file->data, n_elems);
 }