Fix the build with gcc-12 -Wuse-after-free
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
diff --git a/programs/test/metatest.c b/programs/test/metatest.c
index 2973cce..b8dffa9 100644
--- a/programs/test/metatest.c
+++ b/programs/test/metatest.c
@@ -46,6 +46,12 @@
*/
volatile int false_but_the_compiler_does_not_know = 0;
+/* Hide calls to calloc/free from static checkers such as
+ * `gcc-12 -Wuse-after-free`, to avoid compile-time complaints about
+ * code where we do mean to cause a runtime error. */
+void * (* volatile calloc_but_the_compiler_does_not_know)(size_t, size_t) = mbedtls_calloc;
+void(*volatile free_but_the_compiler_does_not_know)(void *) = mbedtls_free;
+
/* Set n bytes at the address p to all-bits-zero, in such a way that
* the compiler should not know that p is all-bits-zero. */
static void set_to_zero_but_the_compiler_does_not_know(volatile void *p, size_t n)
@@ -98,9 +104,9 @@
void read_after_free(const char *name)
{
(void) name;
- volatile char *p = mbedtls_calloc(1, 1);
+ volatile char *p = calloc_but_the_compiler_does_not_know(1, 1);
*p = 'a';
- mbedtls_free((void *) p);
+ free_but_the_compiler_does_not_know((void *) p);
/* Undefined behavior (read after free) */
mbedtls_printf("%u\n", (unsigned) *p);
}
@@ -108,11 +114,11 @@
void double_free(const char *name)
{
(void) name;
- volatile char *p = mbedtls_calloc(1, 1);
+ volatile char *p = calloc_but_the_compiler_does_not_know(1, 1);
*p = 'a';
- mbedtls_free((void *) p);
+ free_but_the_compiler_does_not_know((void *) p);
/* Undefined behavior (double free) */
- mbedtls_free((void *) p);
+ free_but_the_compiler_does_not_know((void *) p);
}
void read_uninitialized_stack(const char *name)
@@ -132,7 +138,7 @@
void memory_leak(const char *name)
{
(void) name;
- volatile char *p = mbedtls_calloc(1, 1);
+ volatile char *p = calloc_but_the_compiler_does_not_know(1, 1);
mbedtls_printf("%u\n", (unsigned) *p);
/* Leak of a heap object */
}