[Gmp-commit] /var/hg/gmp: mini-gmp: Fix undefined NULL pointer arithmetic in ...

[mercurial at gmplib.org]

details:   /var/hg/gmp/rev/b06ade444025
changeset: 18487:b06ade444025
user:      Niels Möller <nisse at lysator.liu.se>
date:      Wed Aug 27 08:08:18 2025 +0200
description:
mini-gmp: Fix undefined NULL pointer arithmetic in mpz_import.

* mini-gmp/mini-gmp.c (mpz_import): Return early when count == 0, to avoid
undefined behavior with pointer arithmetic, if the corresponding
src pointer is NULL. Reported by Bruno Haible.

diffstat:

 mini-gmp/ChangeLog  |  6 ++++++
 mini-gmp/mini-gmp.c |  5 +++++
 2 files changed, 11 insertions(+), 0 deletions(-)

diffs (28 lines):

diff -r f1c983debf6c -r b06ade444025 mini-gmp/ChangeLog
--- a/mini-gmp/ChangeLog	Thu Jun 19 09:27:33 2025 +0200
+++ b/mini-gmp/ChangeLog	Wed Aug 27 08:08:18 2025 +0200
@@ -1,3 +1,9 @@
+2025-08-27  Niels Möller  <nisse at lysator.liu.se>
+
+	* mini-gmp.c (mpz_import): Return early when count == 0, to avoid
+	undefined behavior with pointer arithmetic, if the corresponding
+	src pointer is NULL. Reported by Bruno Haible.
+
 2025-06-19  Niels Möller  <nisse at lysator.liu.se>
 
 	* tests/t-gcd.c (test_one): Fix memory leak.
diff -r f1c983debf6c -r b06ade444025 mini-gmp/mini-gmp.c
--- a/mini-gmp/mini-gmp.c	Thu Jun 19 09:27:33 2025 +0200
+++ b/mini-gmp/mini-gmp.c	Wed Aug 27 08:08:18 2025 +0200
@@ -4515,6 +4515,11 @@
   assert (order == 1 || order == -1);
   assert (endian >= -1 && endian <= 1);
 
+  if (count == 0)
+    {
+      r->_mp_size = 0;
+      return;
+    }
   if (endian == 0)
     endian = gmp_detect_endian ();