vfprintf: Fix memory with large width and precision [BZ #19931]
Commit Message
On 04/14/2016 06:17 PM, Paul Eggert wrote:
> On 04/14/2016 05:22 AM, Florian Weimer wrote:
>> + /* Deallocate any previously allocated buffer because it is
>> + too small. */
>> + if (__glibc_unlikely (workstart != NULL))
>> + free (workstart);
>> if (__glibc_unlikely (prec >= INT_MAX / sizeof (CHAR_T) - 32))
>
> Why don't we need a 'workstart = NULL' after freeing workstart, which is
> the pattern used elsewhere? If it's not needed here, it'd be helpful to
> have a comment saying why not.
Ugh, right. I swear it was there at some point. I've enhanced the test
to catch this.
Florian
Comments
On 04/15/2016 05:01 AM, Florian Weimer wrote:
> Ugh, right. I swear it was there at some point. I've enhanced the
> test to catch this.
Thanks, this looks good to me.
2016-04-15 Florian Weimer <fweimer@redhat.com>
[BZ #19931]
* stdio-common/tst-vfprintf-width-prec.c: New file.
* stdio-common/Makefile (tests): Add tst-vfprintf-width-prec.
(tests-special): Add tst-vfprintf-width-prec-mem.out.
(generated): Add mtrace-related files.
(tst-vfprintf-width-prec-ENV): Set MALLOC_TRACE.
(tst-%-mem.out): New pattern rule, replaces
tst-printf-bz18872-mem.out.
* stdio-common/vfprintf.c (vfprintf): When handling a precision
specifier, deallocate any previously allocated work buffer.
@@ -58,16 +58,18 @@ tests := tstscanf test_rdwr test-popen tstgetln test-fseek \
scanf16 scanf17 tst-setvbuf1 tst-grouping bug23 bug24 \
bug-vfprintf-nargs tst-long-dbl-fphex tst-fphex-wide tst-sprintf3 \
bug25 tst-printf-round bug23-2 bug23-3 bug23-4 bug26 tst-fmemopen3 \
- tst-printf-bz18872
+ tst-printf-bz18872 tst-vfprintf-width-prec
test-srcs = tst-unbputc tst-printf
ifeq ($(run-built-tests),yes)
tests-special += $(objpfx)tst-unbputc.out $(objpfx)tst-printf.out \
$(objpfx)tst-printf-bz18872-mem.out \
- $(objpfx)tst-setvbuf1-cmp.out
+ $(objpfx)tst-setvbuf1-cmp.out \
+ $(objpfx)tst-vfprintf-width-prec-mem.out
generated += tst-printf-bz18872.c tst-printf-bz18872.mtrace \
- tst-printf-bz18872-mem.out
+ tst-printf-bz18872-mem.out \
+ tst-vfprintf-width-prec.mtrace tst-vfprintf-width-prec-mem.out
endif
include ../Rules
@@ -86,6 +88,8 @@ $(objpfx)tst-swprintf.out: $(gen-locales)
endif
tst-printf-bz18872-ENV = MALLOC_TRACE=$(objpfx)tst-printf-bz18872.mtrace
+tst-vfprintf-width-prec-ENV = \
+ MALLOC_TRACE=$(objpfx)tst-vfprintf-width-prec.mtrace
$(objpfx)tst-unbputc.out: tst-unbputc.sh $(objpfx)tst-unbputc
$(SHELL) $< $(common-objpfx) '$(test-program-prefix)'; \
@@ -100,8 +104,8 @@ $(objpfx)tst-printf.out: tst-printf.sh $(objpfx)tst-printf
$(objpfx)tst-printf-bz18872.c: tst-printf-bz18872.sh
rm -f $@ && $(BASH) $^ > $@.new && mv $@.new $@
-$(objpfx)tst-printf-bz18872-mem.out: $(objpfx)tst-printf-bz18872.out
- $(common-objpfx)malloc/mtrace $(objpfx)tst-printf-bz18872.mtrace > $@; \
+$(objpfx)tst-%-mem.out: $(objpfx)tst-%.out
+ $(common-objpfx)malloc/mtrace $(objpfx)tst-$*.mtrace > $@; \
$(evaluate-test)
CFLAGS-vfprintf.c = -Wno-uninitialized
new file mode 100644
@@ -0,0 +1,107 @@
+/* Test for memory leak with large width and precision.
+ Copyright (C) 1991-2016 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 <mcheck.h>
+#include <stdio.h>
+#include <sys/resource.h>
+#include <wchar.h>
+
+static int
+do_test (void)
+{
+ mtrace ();
+
+ int ret;
+ {
+ char *result;
+ ret = asprintf (&result, "%133000.133001x", 17);
+ if (ret < 0)
+ {
+ printf ("error: asprintf: %m\n");
+ return 1;
+ }
+ free (result);
+ }
+ {
+ wchar_t *result = calloc (ret + 1, sizeof (wchar_t));
+ if (result == NULL)
+ {
+ printf ("error: calloc (%d, %zu): %m", ret + 1, sizeof (wchar_t));
+ return 1;
+ }
+
+ ret = swprintf (result, ret + 1, L"%133000.133001x", 17);
+ if (ret < 0)
+ {
+ printf ("error: swprintf: %d (%m)\n", ret);
+ return 1;
+ }
+ free (result);
+ }
+
+ /* Limit the size of the process, so that the second allocation will
+ fail. */
+ {
+ struct rlimit limit;
+ if (getrlimit (RLIMIT_AS, &limit) != 0)
+ {
+ printf ("getrlimit (RLIMIT_AS) failed: %m\n");
+ return 1;
+ }
+ long target = 200 * 1024 * 1024;
+ if (limit.rlim_cur == RLIM_INFINITY || limit.rlim_cur > target)
+ {
+ limit.rlim_cur = target;
+ if (setrlimit (RLIMIT_AS, &limit) != 0)
+ {
+ printf ("setrlimit (RLIMIT_AS) failed: %m\n");
+ return 1;
+ }
+ }
+ }
+
+ {
+ char *result;
+ ret = asprintf (&result, "%133000.999999999x", 17);
+ if (ret >= 0)
+ {
+ printf ("error: asprintf: incorrect result %d\n", ret);
+ return 1;
+ }
+ }
+ {
+ wchar_t result[100];
+ if (result == NULL)
+ {
+ printf ("error: calloc (%d, %zu): %m", ret + 1, sizeof (wchar_t));
+ return 1;
+ }
+
+ ret = swprintf (result, 100, L"%133000.999999999x", 17);
+ if (ret >= 0)
+ {
+ printf ("error: swprintf: incorrect result %d\n", ret);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
@@ -1564,6 +1564,11 @@ vfprintf (FILE *s, const CHAR_T *format, va_list ap)
prec = 0;
if (prec > width && prec > WORK_BUFFER_SIZE - 32)
{
+ /* Deallocate any previously allocated buffer because it is
+ too small. */
+ if (__glibc_unlikely (workstart != NULL))
+ free (workstart);
+ workstart = NULL;
if (__glibc_unlikely (prec >= INT_MAX / sizeof (CHAR_T) - 32))
{
__set_errno (EOVERFLOW);