[v1,1/3] String: tst-memset-overflow.c Add test for overflow case.
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Commit Message
The following commit:
author Noah Goldstein <goldstein.w.n@gmail.com>
Thu, 20 May 2021 17:13:51 +0000 (13:13 -0400)
commit 6abf27980a947f9b6e514d6b33b83059d39566ae
added a bug to memset so that if destination +
length overflowed memset would return early rather than throw a
Segmentation Fault as is expected behavior:
This commit adds a new test file: tst-memset-overflow.c that is
expected to Segmentation Fault if that bug is not present
Signed-off-by: Noah Goldstein <goldstein.w.n@gmail.com>
---
Currently the test will "FAIL" which is expected. I am unsure,
however, how to get the test to "PASS" while also inducing
Segmentation Faults.
string/Makefile | 2 +-
string/tst-memset-overflow.c | 156 +++++++++++++++++++++++++++++++++++
2 files changed, 157 insertions(+), 1 deletion(-)
create mode 100644 string/tst-memset-overflow.c
Comments
On Mon, 7 Jun 2021, Noah Goldstein via Libc-alpha wrote:
> Currently the test will "FAIL" which is expected. I am unsure,
> however, how to get the test to "PASS" while also inducing
> Segmentation Faults.
You can try defining EXPECTED_SIGNAL to SIGSEGV, though it wouldn't
surprise me if problems arise on some platforms (even if the string
function implementations are logically correct for this case).
On 6/7/21 12:40 PM, Noah Goldstein via Libc-alpha wrote:
> The following commit:
>
> author Noah Goldstein <goldstein.w.n@gmail.com>
> Thu, 20 May 2021 17:13:51 +0000 (13:13 -0400)
> commit 6abf27980a947f9b6e514d6b33b83059d39566ae
>
> added a bug to memset so that if destination +
> length overflowed memset would return early rather than throw a
> Segmentation Fault as is expected behavior:
>
> This commit adds a new test file: tst-memset-overflow.c that is
> expected to Segmentation Fault if that bug is not present
Similar to the memcmp patch, this is undefined behaviour, it doesn't
make sense to add a test for this or to explicitly modify memset to
guarantee a segfault if it has a performance impact.
Patch 2/3 looks like it could be included on its own since the new tests
don't seem to test undefined behaviour.
Siddhesh
@@ -63,7 +63,7 @@ tests := tester inl-tester noinl-tester testcopy test-ffs \
tst-strtok_r bug-strcoll2 tst-cmp tst-xbzero-opt \
test-endian-types test-endian-file-scope \
test-endian-sign-conversion tst-memmove-overflow \
- test-sig_np
+ tst-memset-overflow test-sig_np
# Both tests require the .mo translation files generated by msgfmt.
tests-translation := tst-strsignal \
new file mode 100644
@@ -0,0 +1,156 @@
+/* Test memset functions.
+ Copyright (C) 1999-2021 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Written by Jakub Jelinek <jakub@redhat.com>, 1999.
+
+ 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
+ <https://www.gnu.org/licenses/>. */
+
+#define TEST_MAIN
+#ifdef TEST_BZERO
+# ifdef TEST_EXPLICIT_BZERO
+# define TEST_NAME "explicit_bzero"
+# else
+# define TEST_NAME "bzero"
+# endif
+#else
+# ifndef WIDE
+# define TEST_NAME "memset"
+# else
+# define TEST_NAME "wmemset"
+# endif /* WIDE */
+#endif /* !TEST_BZERO */
+#define MIN_PAGE_SIZE 131072
+#include "test-string.h"
+
+#ifndef WIDE
+# define MEMSET memset
+# define CHAR char
+# define UCHAR unsigned char
+# define SIMPLE_MEMSET simple_memset
+# define MEMCMP memcmp
+# define BIG_CHAR CHAR_MAX
+#else
+# include <wchar.h>
+# define MEMSET wmemset
+# define CHAR wchar_t
+# define UCHAR wchar_t
+# define SIMPLE_MEMSET simple_wmemset
+# define MEMCMP wmemcmp
+# define BIG_CHAR WCHAR_MAX
+#endif /* WIDE */
+
+CHAR *SIMPLE_MEMSET (CHAR *, int, size_t);
+
+#ifdef TEST_BZERO
+typedef void (*proto_t) (char *, size_t);
+void simple_bzero (char *, size_t);
+void builtin_bzero (char *, size_t);
+
+IMPL (simple_bzero, 0)
+IMPL (builtin_bzero, 0)
+#ifdef TEST_EXPLICIT_BZERO
+IMPL (explicit_bzero, 1)
+#else
+IMPL (bzero, 1)
+#endif
+
+void
+simple_bzero (char *s, size_t n)
+{
+ SIMPLE_MEMSET (s, 0, n);
+}
+
+void
+builtin_bzero (char *s, size_t n)
+{
+ __builtin_bzero (s, n);
+}
+#else
+typedef CHAR *(*proto_t) (CHAR *, int, size_t);
+
+IMPL (SIMPLE_MEMSET, 0)
+# ifndef WIDE
+char *builtin_memset (char *, int, size_t);
+IMPL (builtin_memset, 0)
+# endif /* !WIDE */
+IMPL (MEMSET, 1)
+
+# ifndef WIDE
+char *
+builtin_memset (char *s, int c, size_t n)
+{
+ return __builtin_memset (s, c, n);
+}
+# endif /* !WIDE */
+#endif /* !TEST_BZERO */
+
+CHAR *
+inhibit_loop_to_libcall
+SIMPLE_MEMSET (CHAR *s, int c, size_t n)
+{
+ CHAR *r = s, *end = s + n;
+ while (r != end)
+ *r++ = c;
+ return s;
+}
+
+int
+test_main (void)
+{
+ size_t i, len;
+ const size_t one = 1;
+
+ test_init ();
+
+ printf ("%24s", "");
+ FOR_EACH_IMPL (impl, 0)
+ printf ("\t%s", impl->name);
+ putchar ('\n');
+
+ for (i = 1; i <= 2; ++i)
+ {
+ len = one << (8 * sizeof(size_t) - i);
+ FOR_EACH_IMPL (impl, 0)
+ {
+#ifdef TEST_BZERO
+ CALL (impl, (CHAR *) (buf1), len);
+#else
+ CALL (impl, (CHAR *) (buf1), 0, len);
+#endif
+ printf ("Should have thrown Segmentation Fault For (%p, %zu) %s",
+ buf1, len, impl->name);
+ ret = 1;
+ }
+ }
+ len = 0;
+ for (i = 8 * sizeof(size_t); i != 0; --i)
+ {
+ len |= (one << i);
+ FOR_EACH_IMPL (impl, 0)
+ {
+#ifdef TEST_BZERO
+ CALL (impl, (CHAR *) (buf1), len);
+#else
+ CALL (impl, (CHAR *) (buf1), 0, len);
+#endif
+ printf ("Should have thrown Segmentation Fault For (%p, %zu) %s",
+ buf1, len, impl->name);
+ ret = 1;
+ }
+ }
+ return ret;
+}
+
+#include <support/test-driver.c>