glibc/malloc/tst-posix_memalign.c
Adhemerval Zanella 9bf8e29ca1 malloc: make malloc fail with requests larger than PTRDIFF_MAX (BZ#23741)
As discussed previously on libc-alpha [1], this patch follows up the idea
and add both the __attribute_alloc_size__ on malloc functions (malloc,
calloc, realloc, reallocarray, valloc, pvalloc, and memalign) and limit
maximum requested allocation size to up PTRDIFF_MAX (taking into
consideration internal padding and alignment).

This aligns glibc with gcc expected size defined by default warning
-Walloc-size-larger-than value which warns for allocation larger than
PTRDIFF_MAX.  It also aligns with gcc expectation regarding libc and
expected size, such as described in PR#67999 [2] and previously discussed
ISO C11 issues [3] on libc-alpha.

From the RFC thread [4] and previous discussion, it seems that consensus
is only to limit such requested size for malloc functions, not the system
allocation one (mmap, sbrk, etc.).

The implementation changes checked_request2size to check for both overflow
and maximum object size up to PTRDIFF_MAX. No additional checks are done
on sysmalloc, so it can still issue mmap with values larger than
PTRDIFF_T depending on the requested size.

The __attribute_alloc_size__ is for functions that return a pointer only,
which means it cannot be applied to posix_memalign (see remarks in GCC
PR#87683 [5]). The runtimes checks to limit maximum requested allocation
size does applies to posix_memalign.

Checked on x86_64-linux-gnu and i686-linux-gnu.

[1] https://sourceware.org/ml/libc-alpha/2018-11/msg00223.html
[2] https://gcc.gnu.org/bugzilla//show_bug.cgi?id=67999
[3] https://sourceware.org/ml/libc-alpha/2011-12/msg00066.html
[4] https://sourceware.org/ml/libc-alpha/2018-11/msg00224.html
[5] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87683

	[BZ #23741]
	* malloc/hooks.c (malloc_check, realloc_check): Use
	__builtin_add_overflow on overflow check and adapt to
	checked_request2size change.
	* malloc/malloc.c (__libc_malloc, __libc_realloc, _mid_memalign,
	__libc_pvalloc, __libc_calloc, _int_memalign): Limit maximum
	allocation size to PTRDIFF_MAX.
	(REQUEST_OUT_OF_RANGE): Remove macro.
	(checked_request2size): Change to inline function and limit maximum
	requested size to PTRDIFF_MAX.
	(__libc_malloc, __libc_realloc, _int_malloc, _int_memalign): Limit
	maximum allocation size to PTRDIFF_MAX.
	(_mid_memalign): Use _int_memalign call for overflow check.
	(__libc_pvalloc): Use __builtin_add_overflow on overflow check.
	(__libc_calloc): Use __builtin_mul_overflow for overflow check and
	limit maximum requested size to PTRDIFF_MAX.
	* malloc/malloc.h (malloc, calloc, realloc, reallocarray, memalign,
	valloc, pvalloc): Add __attribute_alloc_size__.
	* stdlib/stdlib.h (malloc, realloc, reallocarray, valloc): Likewise.
	* malloc/tst-malloc-too-large.c (do_test): Add check for allocation
	larger than PTRDIFF_MAX.
	* malloc/tst-memalign.c (do_test): Disable -Walloc-size-larger-than=
	around tests of malloc with negative sizes.
	* malloc/tst-posix_memalign.c (do_test): Likewise.
	* malloc/tst-pvalloc.c (do_test): Likewise.
	* malloc/tst-valloc.c (do_test): Likewise.
	* malloc/tst-reallocarray.c (do_test): Replace call to reallocarray
	with resulting size allocation larger than PTRDIFF_MAX with
	reallocarray_nowarn.
	(reallocarray_nowarn): New function.
	* NEWS: Mention the malloc function semantic change.
2019-04-18 17:30:06 -03:00

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3.1 KiB
C

/* Test for posix_memalign.
Copyright (C) 2013-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <libc-diag.h>
static int errors = 0;
static void
merror (const char *msg)
{
++errors;
printf ("Error: %s\n", msg);
}
static int
do_test (void)
{
void *p;
int ret;
unsigned long pagesize = getpagesize ();
unsigned long ptrval;
p = NULL;
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (7, 0)
/* GCC 7 warns about too-large allocations; here we want to test
that they fail. */
DIAG_IGNORE_NEEDS_COMMENT (7, "-Walloc-size-larger-than=");
#endif
/* An attempt to allocate a huge value should return ENOMEM and
p should remain NULL. */
ret = posix_memalign (&p, sizeof (void *), -1);
#if __GNUC_PREREQ (7, 0)
DIAG_POP_NEEDS_COMMENT;
#endif
if (ret != ENOMEM)
merror ("posix_memalign (&p, sizeof (void *), -1) succeeded.");
if (ret == ENOMEM && p != NULL)
merror ("returned an error but pointer was modified");
free (p);
p = NULL;
/* Test to expose integer overflow in malloc internals from BZ #15857. */
ret = posix_memalign (&p, pagesize, -pagesize);
if (ret != ENOMEM)
merror ("posix_memalign (&p, pagesize, -pagesize) succeeded.");
free (p);
p = NULL;
/* Test to expose integer overflow in malloc internals from BZ #16038. */
ret = posix_memalign (&p, -1, pagesize);
if (ret != EINVAL)
merror ("posix_memalign (&p, -1, pagesize) succeeded.");
free (p);
p = NULL;
/* A zero-sized allocation should succeed with glibc, returning zero
and setting p to a non-NULL value. */
ret = posix_memalign (&p, sizeof (void *), 0);
if (ret != 0 || p == NULL)
merror ("posix_memalign (&p, sizeof (void *), 0) failed.");
free (p);
ret = posix_memalign (&p, 0x300, 10);
if (ret != EINVAL)
merror ("posix_memalign (&p, 0x300, 10) succeeded.");
ret = posix_memalign (&p, 0, 10);
if (ret != EINVAL)
merror ("posix_memalign (&p, 0, 10) succeeded.");
p = NULL;
ret = posix_memalign (&p, 0x100, 10);
if (ret != 0)
merror ("posix_memalign (&p, 0x100, 10) failed.");
if (ret == 0 && p == NULL)
merror ("returned success but pointer is NULL");
ptrval = (unsigned long) p;
if (ret == 0 && (ptrval & 0xff) != 0)
merror ("pointer is not aligned to 0x100");
free (p);
return errors != 0;
}
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"