From: Thomas Egerer <thomas.egerer@secunet.com>
Date: Fri, 6 Sep 2024 11:29:40 +0000 (+0200)
Subject: array: Don't use realloc() with zero size in array_compress()
X-Git-Tag: 6.0.0rc1~50
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cf7fb47788dfb83bb5d8bd0bffdb582e381a2f0a;p=thirdparty%2Fstrongswan.git

array: Don't use realloc() with zero size in array_compress()

The behavior of realloc(3) with zero size was apparently implementation
defined.  While glibc documents the behavior as equivalent to free(3),
that might not apply to other C libraries.  With C17, this behavior has
been deprecated, and with C23, the behavior is now undefined.  It's also
why valgrind warns about this use.

Hence, when array_compress() would call realloc() with a zero size, we
now call free() explicitly and set the pointer to NULL.

Signed-off-by: Thomas Egerer <thomas.egerer@secunet.com>
---

diff --git a/src/libstrongswan/collections/array.c b/src/libstrongswan/collections/array.c
index 8acc8051d5..8b6c6d7397 100644
--- a/src/libstrongswan/collections/array.c
+++ b/src/libstrongswan/collections/array.c
@@ -197,7 +197,17 @@ void array_compress(array_t *array)
 		}
 		if (tail)
 		{
-			array->data = realloc(array->data, get_size(array, array->count));
+			size_t size = get_size(array, array->count);
+
+			if (size)
+			{
+				array->data = realloc(array->data, size);
+			}
+			else
+			{
+				free(array->data);
+				array->data = NULL;
+			}
 			array->tail = 0;
 		}
 	}