Implement rsize_t / RSIZE_MAX (almost) correctly.

The caveat is needed because if you include one of these headers on a system that defines rsize_t without having the correct incantations in your configure.ac, you are going to have a bad time.  But there is no good general solution to the problem.

configure.ac

@@ -51,6 +51,9 @@ AC_TYPE_UINT8_T
 AC_TYPE_UINTMAX_T
 AC_TYPE_UINTPTR_T
 
+AC_CHECK_TYPES([rsize_t], [], [], [[#include <stdint.h>]])
+AC_CHECK_DECL([RSIZE_MAX], [], [], [[#include <stdint.h>]])
+
 ############################################################################
 #
 # Headers and functions

include/cryb/Makefile.am

@@ -24,6 +24,7 @@ cryb_HEADERS += \
 	endian.h \
 	memcpy_s.h \
 	memset_s.h \
+	rsize.h \
 	strchrnul.h \
 	string.h \
 	strlcat.h \

include/cryb/memcpy_s.h

@@ -34,9 +34,13 @@
 #include <cryb/to.h>
 #endif
 
+#ifndef CRYB_RSIZE_H_INCLUDED
+#include <cryb/rsize.h>
+#endif
+
 CRYB_BEGIN
 
-int cryb_memcpy_s(void *, size_t, const void *, size_t);
+int cryb_memcpy_s(void *, rsize_t, const void *, rsize_t);
 
 #if !HAVE_MEMCPY_S
 #undef memcpy_s

include/cryb/memset_s.h

@@ -34,9 +34,13 @@
 #include <cryb/to.h>
 #endif
 
+#ifndef CRYB_RSIZE_H_INCLUDED
+#include <cryb/rsize.h>
+#endif
+
 CRYB_BEGIN
 
-int cryb_memset_s(void *, size_t, int, size_t);
+int cryb_memset_s(void *, rsize_t, int, rsize_t);
 
 #if !HAVE_MEMSET_S
 #undef memset_s

include/cryb/rsize.h

@@ -0,0 +1,41 @@
+/*-
+ * Copyright (c) 2018 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.
+ */
+
+#ifndef CRYB_RSIZE_H_INCLUDED
+#define CRYB_RSIZE_H_INCLUDED
+
+#if !HAVE_RSIZE_T
+typedef size_t rsize_t;
+#endif
+
+#if !HAVE_RSIZE_MAX
+#define RSIZE_MAX (SIZE_MAX >> 1)
+#endif
+
+#endif

lib/core/cryb_memcpy_s.c

@@ -45,7 +45,7 @@
  * range with zeroes on error.
  */
 int
-cryb_memcpy_s(void *d, size_t dsz, const void *s, size_t n)
+cryb_memcpy_s(void *d, rsize_t dsz, const void *s, rsize_t n)
 {
 	unsigned int i;
 
@@ -53,20 +53,20 @@ cryb_memcpy_s(void *d, size_t dsz, const void *s, size_t n)
 	if (d == NULL)
 		return (EINVAL);
 CRYB_DISABLE_COVERAGE
-	if (dsz > SIZE_MAX)
+	if (dsz > RSIZE_MAX)
 		return (ERANGE);
 CRYB_RESTORE_COVERAGE
 	/* recoverable errors */
 	if (s == NULL || n > dsz ||
 CRYB_DISABLE_COVERAGE
-	    n > SIZE_MAX ||
+	    n > RSIZE_MAX ||
 CRYB_RESTORE_COVERAGE
 	    (s >= d && s < d + dsz) || (d >= s && d < s + n)) {
 		memset_s(d, dsz, 0, dsz);
 		if (n > dsz)
 			return (EOVERFLOW);
 CRYB_DISABLE_COVERAGE
-		if (n > SIZE_MAX)
+		if (n > RSIZE_MAX)
 			return (ERANGE);
 CRYB_RESTORE_COVERAGE
 		return (EINVAL);

lib/core/cryb_memset_s.c

@@ -44,14 +44,14 @@
  * is overwritten even if the data will never be read.
  */
 int
-cryb_memset_s(void *d, size_t dsz, int ch, size_t n)
+cryb_memset_s(void *d, rsize_t dsz, int ch, rsize_t n)
 {
 	unsigned int i;
 
 	if (d == NULL)
 		return (EINVAL);
 CRYB_DISABLE_COVERAGE
-	if (dsz > SIZE_MAX || n > SIZE_MAX)
+	if (dsz > RSIZE_MAX || n > RSIZE_MAX)
 		return (ERANGE);
 CRYB_RESTORE_COVERAGE
 	for (i = 0; i < n && i < dsz; ++i)

t/t_memcpy_s.c

@@ -44,11 +44,11 @@
 struct t_plain_case {
 	const char *desc;
 	const char in[T_BUF_LEN];
-	size_t dsz;
+	rsize_t dsz;
 	const char s[T_BUF_LEN];
-	size_t len;
+	rsize_t len;
 	const char out[T_BUF_LEN];
-	size_t outlen;
+	rsize_t outlen;
 	int ret;
 };
 
@@ -115,7 +115,8 @@ t_memcpy_s(char **desc CRYB_UNUSED, void *arg)
 struct t_overlap_case {
 	const char *desc;
 	const char *in;
-	size_t s_off, s_len, d_off, d_len;
+	size_t s_off, d_off;
+	rsize_t s_len, d_len;
 	const char out[T_BUF_LEN];
 	int ret;
 };