Add a memset_s() implementation (cf. C11 / WG14 N1381)

configure.ac

@@ -54,6 +54,11 @@ AC_CHECK_HEADERS([sys/uio.h sys/ktrace.h], [], [], [[
 ]])
 AC_CHECK_FUNCS([utrace])
 
+# C11 features
+# XXX our version has an incorrect prototype due to the lack of a test
+# for the existence of rsize_t and RSIZE_MAX.
+AC_CHECK_FUNCS([memset_s])
+
 ############################################################################
 #
 # Extra libraries

lib/core/Makefile.am

@@ -4,6 +4,7 @@ lib_LTLIBRARIES = libcryb-core.la
 
 libcryb_core_la_SOURCES = \
 	cryb_core.c \
+	cryb_memset_s.c \
 	string.c \
 	cryb_strlcat.c \
 	cryb_strlcpy.c \

lib/core/cryb_memset_s.c

@@ -0,0 +1,56 @@
+/*-
+ * Copyright (c) 2015 The University of Oslo
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+
+#include <cryb/memset_s.h>
+
+/*
+ * Like memset(), but checks for overflow and guarantees that the buffer
+ * is overwritten even if the data will never be read.
+ */
+int
+cryb_memset_s(void *s, size_t smax, int c, size_t n)
+{
+	unsigned int i;
+
+	if (s == NULL)
+		return (EINVAL);
+	for (i = 0; i < n && i < smax; ++i)
+		((volatile unsigned char *)s)[i] = (unsigned char)c;
+	if (n > smax)
+		return (EOVERFLOW);
+	return (0);
+}

t/Makefile.am

@@ -36,11 +36,12 @@ endif
 TESTS =
 
 # libcryb-core
-TESTS += t_ctype t_endian t_strlcat t_strlcmp t_strlcpy
+TESTS += t_ctype t_endian t_memset_s t_strlcat t_strlcmp t_strlcpy
 TESTS += t_string t_wstring
 EXTRA_DIST += t__string.c
 t_ctype_LDADD = $(libt) $(libcore)
 t_endian_LDADD = $(libt) $(libcore)
+t_memset_s_LDADD = $(libt) $(libcore)
 t_strlcat_LDADD = $(libt) $(libcore)
 t_strlcmp_LDADD = $(libt) $(libcore)
 t_strlcpy_LDADD = $(libt) $(libcore)

t/t_memset_s.c

@@ -0,0 +1,147 @@
+/*-
+ * Copyright (c) 2015 The University of Oslo
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote
+ *    products derived from this software without specific prior written
+ *    permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include "cryb/impl.h"
+
+#include <errno.h>
+#include <stdint.h>
+#include <string.h>
+
+#undef HAVE_MEMSET_S
+#include <cryb/memset_s.h>
+
+#include "t.h"
+
+#define T_BUF_LEN	32
+
+struct t_case {
+	const char *desc;
+	const char in[T_BUF_LEN];
+	size_t smax;
+	int c;
+	size_t len;
+	const char out[T_BUF_LEN];
+	size_t outlen;
+	int ret;
+};
+
+/***************************************************************************
+ * Test cases
+ */
+static struct t_case t_cases[] = {
+	{
+		.desc	= "zero",
+		.in	= "squeamish ossifrage",
+		.smax	= sizeof "squeamish ossifrage" - 1,
+		.c	= 'x',
+		.len	= 0,
+		.out	= "squeamish ossifrage",
+		.ret	= 0,
+	},
+	{
+		.desc	= "short",
+		.in	= "squeamish ossifrage",
+		.smax	= sizeof "squeamish ossifrage" - 1,
+		.c	= 'x',
+		.len	= 9,
+		.out	= "xxxxxxxxx ossifrage",
+		.ret	= 0,
+	},
+	{
+		.desc	= "exact",
+		.in	= "squeamish ossifrage",
+		.smax	= sizeof "squeamish ossifrage" - 1,
+		.c	= 'x',
+		.len	= sizeof "squeamish ossifrage" - 1,
+		.out	= "xxxxxxxxxxxxxxxxxxx",
+		.ret	= 0,
+	},
+	{
+		.desc	= "long",
+		.in	= "squeamish ossifrage",
+		.smax	= sizeof "squeamish ossifrage" - 1,
+		.c	= 'x',
+		.len	= sizeof "squeamish ossifrage" + 1,
+		.out	= "xxxxxxxxxxxxxxxxxxx",
+		.ret	= EOVERFLOW,
+	},
+};
+
+/***************************************************************************
+ * Test function
+ */
+static int
+t_memset_s(char **desc CRYB_UNUSED, void *arg)
+{
+	struct t_case *t = arg;
+	char buf[T_BUF_LEN];
+	int ret;
+
+	memcpy(buf, t->in, T_BUF_LEN);
+	ret = memset_s(buf, t->smax, t->c, t->len);
+	return (t_compare_i(t->ret, ret) &
+	    t_compare_mem(t->out, buf, T_BUF_LEN));
+}
+
+/***************************************************************************
+ * Test function (NULL)
+ */
+static int
+t_memset_s_null(char **desc CRYB_UNUSED, void *arg)
+{
+	int ret;
+
+	(void)arg;
+	ret = memset_s(NULL, 1, 0, 1);
+	return (t_compare_i(EINVAL, ret));
+}
+
+
+/***************************************************************************
+ * Boilerplate
+ */
+
+int
+t_prepare(int argc, char *argv[])
+{
+	int i, n;
+
+	(void)argc;
+	(void)argv;
+	t_add_test(t_memset_s_null, NULL, "null");
+	n = sizeof t_cases / sizeof t_cases[0];
+	for (i = 0; i < n; ++i)
+		t_add_test(t_memset_s, &t_cases[i], t_cases[i].desc);
+	return (0);
+}
+
+void
+t_cleanup(void)
+{
+}