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From 01bffc013cdad1e0c45db7aa57efb2bee61f3338 Mon Sep 17 00:00:00 2001
From: Siddhesh Poyarekar <siddhesh@sourceware.org>
Date: Fri, 29 Oct 2021 14:53:55 +0530
Subject: [PATCH] Handle NULL input to malloc_usable_size [BZ #28506]
Hoist the NULL check for malloc_usable_size into its entry points in
malloc-debug and malloc and assume non-NULL in all callees. This fixes
BZ #28506
Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
(cherry picked from commit 88e316b06414ee7c944cd6f8b30b07a972b78499)
---
malloc/malloc-debug.c | 13 +++++++------
malloc/malloc.c | 25 +++++++++----------------
malloc/tst-malloc-usable.c | 22 +++++++++-------------
3 files changed, 25 insertions(+), 35 deletions(-)
diff --git a/malloc/malloc-debug.c b/malloc/malloc-debug.c
index 9922ef5..3d7e6d4 100644
--- a/malloc/malloc-debug.c
+++ b/malloc/malloc-debug.c
@@ -1,5 +1,6 @@
/* Malloc debug DSO.
Copyright (C) 2021 Free Software Foundation, Inc.
+ Copyright The GNU Toolchain Authors.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -399,17 +400,17 @@ strong_alias (__debug_calloc, calloc)
size_t
malloc_usable_size (void *mem)
{
+ if (mem == NULL)
+ return 0;
+
if (__is_malloc_debug_enabled (MALLOC_MCHECK_HOOK))
return mcheck_usable_size (mem);
if (__is_malloc_debug_enabled (MALLOC_CHECK_HOOK))
return malloc_check_get_size (mem);
- if (mem != NULL)
- {
- mchunkptr p = mem2chunk (mem);
- if (DUMPED_MAIN_ARENA_CHUNK (p))
- return chunksize (p) - SIZE_SZ;
- }
+ mchunkptr p = mem2chunk (mem);
+ if (DUMPED_MAIN_ARENA_CHUNK (p))
+ return chunksize (p) - SIZE_SZ;
return musable (mem);
}
diff --git a/malloc/malloc.c b/malloc/malloc.c
index e065785..7882c70 100644
--- a/malloc/malloc.c
+++ b/malloc/malloc.c
@@ -1,5 +1,6 @@
/* Malloc implementation for multiple threads without lock contention.
Copyright (C) 1996-2021 Free Software Foundation, Inc.
+ Copyright The GNU Toolchain Authors.
This file is part of the GNU C Library.
Contributed by Wolfram Gloger <wg@malloc.de>
and Doug Lea <dl@cs.oswego.edu>, 2001.
@@ -5009,20 +5010,13 @@ __malloc_trim (size_t s)
static size_t
musable (void *mem)
{
- mchunkptr p;
- if (mem != 0)
- {
- size_t result = 0;
-
- p = mem2chunk (mem);
+ mchunkptr p = mem2chunk (mem);
- if (chunk_is_mmapped (p))
- result = chunksize (p) - CHUNK_HDR_SZ;
- else if (inuse (p))
- result = memsize (p);
+ if (chunk_is_mmapped (p))
+ return chunksize (p) - CHUNK_HDR_SZ;
+ else if (inuse (p))
+ return memsize (p);
- return result;
- }
return 0;
}
@@ -5030,10 +5024,9 @@ musable (void *mem)
size_t
__malloc_usable_size (void *m)
{
- size_t result;
-
- result = musable (m);
- return result;
+ if (m == NULL)
+ return 0;
+ return musable (m);
}
#endif
diff --git a/malloc/tst-malloc-usable.c b/malloc/tst-malloc-usable.c
index a1074b7..b0d702b 100644
--- a/malloc/tst-malloc-usable.c
+++ b/malloc/tst-malloc-usable.c
@@ -2,6 +2,7 @@
MALLOC_CHECK_ exported to a positive value.
Copyright (C) 2012-2021 Free Software Foundation, Inc.
+ Copyright The GNU Toolchain Authors.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -21,29 +22,24 @@
#include <malloc.h>
#include <string.h>
#include <stdio.h>
+#include <support/support.h>
+#include <support/check.h>
static int
do_test (void)
{
size_t usable_size;
void *p = malloc (7);
- if (!p)
- {
- printf ("memory allocation failed\n");
- return 1;
- }
+ TEST_VERIFY_EXIT (p != NULL);
usable_size = malloc_usable_size (p);
- if (usable_size != 7)
- {
- printf ("malloc_usable_size: expected 7 but got %zu\n", usable_size);
- return 1;
- }
-
+ TEST_COMPARE (usable_size, 7);
memset (p, 0, usable_size);
free (p);
+
+ TEST_COMPARE (malloc_usable_size (NULL), 0);
+
return 0;
}
-#define TEST_FUNCTION do_test ()
-#include "../test-skeleton.c"
+#include "support/test-driver.c"
--
1.8.3.1
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