Add a testcase which validates that the same buffer can be passed to

rijndael_blockDecrypt() as both input and output.

This property is important because inside rijndael we can get away
with allocating just a 16 byte "work" buffer on the stack (which
is very cheap), whereas the calling code would need to allocate the
full sized buffer, and in all likelyhood would have to do so with
an expensive malloc(9).

sys/crypto/rijndael/Makefile

@@ -0,0 +1,12 @@
+# $FreeBSD$
+
+PROG=test00
+NOMAN=1
+SRCS= ${PROG}.c rijndael-alg-fst.c rijndael-api-fst.c
+
+CFLAGS += -I${.CURDIR}/../.. -g -static
+
+.include <bsd.prog.mk>
+
+test:	${PROG}
+	./${PROG}

sys/crypto/rijndael/test00.c

@@ -0,0 +1,75 @@
+/*-
+ * Copyright (c) 2003 Poul-Henning Kamp
+ * 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.
+ *
+ * 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.
+ *
+ * $FreeBSD$
+ *
+ * This test checks for inplace decryption working.  This is the case
+ * where the same buffer is passed as input and output to
+ * rijndael_blockDecrypt().
+ */
+
+#include <stdio.h>
+#include <sys/param.h>
+#include <sys/types.h>
+
+#include <crypto/rijndael/rijndael.h>
+
+#define LL 32 
+int
+main(int argc, char **argv)
+{
+	keyInstance ki;
+	cipherInstance ci;
+	uint8_t key[16];
+	uint8_t in[LL];
+	uint8_t out[LL];
+	int i, j;
+
+	rijndael_cipherInit(&ci, MODE_CBC, NULL);
+	for (i = 0; i < 16; i++)
+		key[i] = i;
+	rijndael_makeKey(&ki, DIR_DECRYPT, 128, key);
+	for (i = 0; i < LL; i++)
+		in[i] = i;
+	rijndael_blockDecrypt(&ci, &ki, in, LL * 8, out);
+	for (i = 0; i < LL; i++)
+		printf("%02x", out[i]);
+	putchar('\n');
+	rijndael_blockDecrypt(&ci, &ki, in, LL * 8, in);
+	j = 0;
+	for (i = 0; i < LL; i++) {
+		printf("%02x", in[i]);
+		if (in[i] != out[i])
+			j++;
+	}
+	putchar('\n');
+	if (j != 0) {
+		fprintf(stderr,
+		    "Error: inplace decryption fails in %d places\n", j);
+		return (1);
+	} else {
+		return (0);
+	}
+}