add support for -C (itercountk) option of loop-AES if libgcrypt is available

Signed-off-by: Ludwig Nussel <ludwig.nussel@suse.de>

Index: hashalot-0.3/Makefile.am
===================================================================
--- hashalot-0.3/Makefile.am.orig
+++ hashalot-0.3/Makefile.am
@@ -3,6 +3,9 @@ sbin_PROGRAMS = hashalot
 
 man_MANS = hashalot.1
 
+hashalot_CFLAGS = $(LIBGCRYPT_CFLAGS)
+hashalot_LDFLAGS = $(LIBGCRYPT_LIBS)
+
 hashalot_SOURCES = hashalot.c rmd160.c rmd160.h sha512.c sha512.h
 
 install-exec-hook:
Index: hashalot-0.3/configure.ac
===================================================================
--- hashalot-0.3/configure.ac.orig
+++ hashalot-0.3/configure.ac
@@ -8,5 +8,6 @@ AC_PROG_LN_S
 AC_HEADER_STDC
 AC_CHECK_HEADERS(libgen.h stdio.h stdlib.h string.h unistd.h assert.h sys/types.h sys/mman.h endian.h , , [ AC_MSG_ERROR(required header not found)])
 AC_CHECK_FUNCS(getopt snprintf , , [ AC_MSG_ERROR(required function not found)])
+AM_PATH_LIBGCRYPT(,[AC_DEFINE([HAVE_LIBGCRYPT], 1)])
 
 AC_OUTPUT(Makefile)
Index: hashalot-0.3/hashalot.c
===================================================================
--- hashalot-0.3/hashalot.c.orig
+++ hashalot-0.3/hashalot.c
@@ -25,6 +25,10 @@
 #include <sys/types.h>
 #include <sys/mman.h>
 
+#if HAVE_LIBGCRYPT
+#include <gcrypt.h>
+#endif
+
 #include "rmd160.h"
 #include "sha512.h"
 
@@ -97,9 +101,9 @@ show_usage(const char argv0[])
 
 	fprintf (stdout,
 		 "usage:\n"
-		 "    hashalot [ -x ] [ -s SALT ] [ -n _#bytes_ ] HASHTYPE\n"
+		 "    hashalot [ -x ] [ -s SALT ] [ -n _#bytes_ ] [ -C itercountk ] HASHTYPE\n"
 		 "  or\n"
-		 "    HASHTYPE [ -x ] [ -s SALT ] [ -n _#bytes_ ]\n"
+		 "    HASHTYPE [ -x ] [ -s SALT ] [ -n _#bytes_ ] [ -C itercountk ]\n"
 		 "\n"
 		 "supported values for HASHTYPE: ");
 
@@ -214,8 +218,9 @@ main(int argc, char *argv[]) 
 	size_t hashlen = 0;
 	phash_func_t func;
 	int hex_output = 0, c;
+	unsigned long itercountk = 0;
 
-	while ((c = getopt(argc, argv, "n:s:x")) != -1) {
+	while ((c = getopt(argc, argv, "n:s:xC:")) != -1) {
 		switch (c) {
 		case 'n':
 			hashlen = strtoul(optarg, &p, 0);
@@ -233,6 +238,9 @@ main(int argc, char *argv[]) 
 		case 'x':
 			hex_output++;
 			break;
+		case 'C':
+			itercountk = atoi(optarg);
+			break;
                 default:
                         show_usage(argv[0]);
 			exit(EXIT_FAILURE);
@@ -257,6 +265,8 @@ main(int argc, char *argv[]) 
 	 * plus a newline, plus a null */
 	passhash = xmalloc(2*hashlen + 2);
 
+	memset(passhash, 0, 2*hashlen+2);
+
 	/* try to lock memory so it doesn't get swapped out for sure */
 	if (mlockall(MCL_CURRENT | MCL_FUTURE) == -1) {
 		perror("mlockall");
@@ -268,6 +278,69 @@ main(int argc, char *argv[]) 
 	if (salt)
 		pass = salt_passphrase(pass, salt);
 	hashlen = func(passhash, hashlen, pass, strlen(pass));
+
+	if(itercountk) /* from loop-AES */
+	{
+#if HAVE_LIBGCRYPT
+		gcry_cipher_hd_t ctx; 
+		gcry_error_t err;
+		char tmp[32];
+		char out[32];
+
+		if(hashlen > 32) {
+			fprintf(stderr, "WARNING: hashlen truncated to 32\n");
+			hashlen = 32;
+		}
+
+		if(!gcry_check_version("1.1.0")) {
+			fprintf(stderr, "libgcrypt initialization failed\n");
+			exit(EXIT_FAILURE);
+		}
+
+		memset(out, 0, sizeof(out));
+		memcpy(out, passhash, hashlen);
+
+		err = gcry_cipher_open(&ctx, GCRY_CIPHER_AES, GCRY_CIPHER_MODE_CBC, 0);
+		if(err) 
+		{
+			fprintf(stderr, "can't initialize AES: %s\n", gcry_strerror (err));
+			exit(EXIT_FAILURE);
+		}
+
+		/*
+		 * Set up AES-256 encryption key using same password and hash function
+		 * as before but with password bit 0 flipped before hashing. That key
+		 * is then used to encrypt actual loop key 'itercountk' thousand times.
+		 */
+		pass[0] ^= 1;
+		func(&tmp[0], 32, pass, strlen(pass)); 
+		gcry_cipher_setkey(ctx, &tmp[0], 32);
+		itercountk *= 1000;
+		while(itercountk > 0) { 
+			gcry_cipher_reset(ctx);
+			gcry_cipher_setiv(ctx, NULL, 0);
+			/* encrypt both 128bit blocks with AES-256 */
+			gcry_cipher_encrypt(ctx, &out[ 0], 16, &out[ 0], 16); 
+			gcry_cipher_reset(ctx);
+			gcry_cipher_setiv(ctx, NULL, 0);
+			gcry_cipher_encrypt(ctx, &out[16], 16, &out[16], 16); 
+			/* exchange upper half of first block with lower half of second block */
+			memcpy(&tmp[0], &out[8], 8);
+			memcpy(&out[8], &out[16], 8);
+			memcpy(&out[16], &tmp[0], 8);
+			itercountk--;
+		}
+		memset(&tmp[0], 0, sizeof(tmp));
+
+		memcpy(passhash, out, hashlen);
+
+		gcry_cipher_close(ctx);
+#else
+		fprintf(stderr, "libgcrypt support is required for option -C\n");
+		exit(EXIT_FAILURE);
+#endif
+
+	}
 	memset (pass, 0, strlen (pass)); /* paranoia */
 	free(pass);