malloc: Fix -Wuse-after-free warning in tst-mallocalign1 [BZ #26779]

The test leaks bits from the freed pointer via the return value
in ret, and the compiler correctly identifies this issue.
We switch the test to use TEST_VERIFY and terminate the test
if any of the pointers return an unexpected alignment.

This fixes another -Wuse-after-free error when compiling glibc
with gcc 12.

Tested on x86_64 and i686 without regression.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
(cherry picked from commit 3a7bed5f5a)
This commit is contained in:
Carlos O'Donell 2022-01-28 15:14:29 -05:00 committed by Florian Weimer
parent c5c666f349
commit 6484ae5b8c

View File

@ -20,6 +20,7 @@
#include <stdlib.h>
#include <inttypes.h>
#include <malloc-size.h>
#include <support/check.h>
static void *
test (size_t s)
@ -31,41 +32,42 @@ test (size_t s)
return p;
}
#define ALIGNED(p) (((uintptr_t )p & MALLOC_ALIGN_MASK) == 0)
static int
do_test (void)
{
void *p;
int ret = 0;
p = test (2);
ret |= (uintptr_t) p & MALLOC_ALIGN_MASK;
TEST_VERIFY (ALIGNED (p));
free (p);
p = test (8);
ret |= (uintptr_t) p & MALLOC_ALIGN_MASK;
TEST_VERIFY (ALIGNED (p));
free (p);
p = test (13);
ret |= (uintptr_t) p & MALLOC_ALIGN_MASK;
TEST_VERIFY (ALIGNED (p));
free (p);
p = test (16);
ret |= (uintptr_t) p & MALLOC_ALIGN_MASK;
TEST_VERIFY (ALIGNED (p));
free (p);
p = test (23);
ret |= (uintptr_t) p & MALLOC_ALIGN_MASK;
TEST_VERIFY (ALIGNED (p));
free (p);
p = test (43);
ret |= (uintptr_t) p & MALLOC_ALIGN_MASK;
TEST_VERIFY (ALIGNED (p));
free (p);
p = test (123);
ret |= (uintptr_t) p & MALLOC_ALIGN_MASK;
TEST_VERIFY (ALIGNED (p));
free (p);
return ret;
return 0;
}
#include <support/test-driver.c>