From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date: Fri, 18 Apr 2025 12:27:29 +0000 (-0300)
Subject: locale: Fix UB on insert_weights
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=915959c55d2ebe05b7a3b31f633fc17d4f7f913b;p=thirdparty%2Fglibc.git

locale: Fix UB on insert_weights

The ubsan triggers:

UBSAN: Undefined behaviour in programs/ld-collate.c:862:5 null pointer passed as argument 2, nonnull attribute declared at unknown:0:0,

The memcpy is only requires if current 'weights' is nonnull, so
check it before calling it.
---

diff --git a/locale/programs/ld-collate.c b/locale/programs/ld-collate.c
index 7de3ba064d..4fa08bd273 100644
--- a/locale/programs/ld-collate.c
+++ b/locale/programs/ld-collate.c
@@ -858,7 +858,8 @@ insert_weights (struct linereader *ldfile, struct element_t *elem,
 		  max += 10;
 		  newp = (struct element_t **)
 		    alloca (max * sizeof (struct element_t *));
-		  memcpy (newp, weights, cnt * sizeof (struct element_t *));
+		  if (weights != NULL)
+		    memcpy (newp, weights, cnt * sizeof (struct element_t *));
 		  weights = newp;
 		}
 	      weights[cnt++] = charelem;