From: Andrey Rys <rys@lynxlynx.ru>
Date: Sun, 28 Aug 2022 13:45:24 +0000 (+0200)
Subject: -X: add simple XOR mode (embedded xor tool)
X-Git-Url: https://jxself.org/git/?a=commitdiff_plain;h=b0637473e28d682b2ec870dd62cc05eb749842d0;p=tfcrypt.git

-X: add simple XOR mode (embedded xor tool)
---

diff --git a/VERSION b/VERSION
index 3fdcd7c..38b10c1 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-67
+68
diff --git a/tfc_error.c b/tfc_error.c
index 6f994ef..953ba07 100644
--- a/tfc_error.c
+++ b/tfc_error.c
@@ -114,7 +114,7 @@ void usage(void)
 
 	if (optopt == 'V') {
 		tfc_say("tfcrypt toolkit, version %s.", _TFCRYPT_VERSION);
-		if (ctr_mode != TFC_MODE_PLAIN) {
+		if (do_edcrypt != TFC_DO_PLAIN) {
 			char shash[64];
 
 			hash_defaults(shash, sizeof(shash));
@@ -210,6 +210,22 @@ void usage(void)
 		tfc_say("no error checking is performed.");
 		tfc_say("\n");
 	}
+	else if (!strcmp(progname, "xor")) {
+		is_embedded_prog = YES;
+		tfc_say("usage: %s [sourceX] [sourceY] [output]", progname);
+		tfc_say("\n");
+		tfc_say("tfcrypt embedded high performance XOR tool.");
+		tfc_say("It does XOR (multiply modulo 2) of each byte from sourceX");
+		tfc_say("each byte of sourceY and writes output.");
+		tfc_say("If filenames omitted, it is assumed to operate over");
+		tfc_say("standard in to standard out.");
+		tfc_say("If any of source files is shorter than another,");
+		tfc_say("then output is truncated to length of the shortest one.");
+		tfc_say("\n");
+		tfc_say("No error checking is performed.");
+		tfc_say("Please use iotool options there.");
+		tfc_say("\n");
+	}
 	else if (!strcmp(progname, "tfbench")) {
 		is_embedded_prog = YES;
 		tfc_say("usage: %s seconds", progname);
@@ -364,6 +380,7 @@ void usage(void)
 	tfc_say("    xctr=val: specify size in bytes of initial counter prepended or read.");
 	tfc_say("    fullkey: occupy tweak space by key space, extending key size by 256 bits.");
 	tfc_say("  -P: plain IO mode: disable encryption/decryption code at all.");
+	tfc_say("  -X: XOR IO mode: same as -P but do XOR of two streams.");
 	tfc_say("\n");
 	tfc_say("Default is to ask for password, then encrypt stdin into stdout.");
 	tfc_say("Some cmdline parameters may be mutually exclusive, or they can");
diff --git a/tfc_misc.c b/tfc_misc.c
index 5902896..2aa58df 100644
--- a/tfc_misc.c
+++ b/tfc_misc.c
@@ -107,6 +107,7 @@ tfc_yesno tfc_is_freestream(int mode)
 {
 	switch (mode) {
 		case TFC_MODE_PLAIN:
+		case TFC_MODE_XOR:
 		case TFC_MODE_STREAM: return YES;
 	}
 
diff --git a/tfc_random.c b/tfc_random.c
index 0a529d4..99612d3 100644
--- a/tfc_random.c
+++ b/tfc_random.c
@@ -150,7 +150,7 @@ void gen_write_bytes(const char *foutname, tfc_fsize offset, tfc_fsize nrbytes)
 			xerror(ignore_seek_errors, NO, NO, "%s: seek failed", foutname);
 	}
 
-	if (ctr_mode == TFC_MODE_PLAIN) memset(srcblk, 0, sizeof(srcblk));
+	if (do_edcrypt == TFC_DO_PLAIN) memset(srcblk, 0, sizeof(srcblk));
 
 	if (verbose) tfc_nfsay(stderr, "%s: writing %lld bytes to %s ... ",
 		tfc_format_pid(progname), nrbytes, foutname);
@@ -162,7 +162,7 @@ void gen_write_bytes(const char *foutname, tfc_fsize offset, tfc_fsize nrbytes)
 		pblk = srcblk;
 		lblock = lrem = blk_len_adj(nrbytes, total_processed_src, blksize);
 
-		if (ctr_mode != TFC_MODE_PLAIN) tfc_getrandom(srcblk, lblock);
+		if (do_edcrypt != TFC_DO_PLAIN) tfc_getrandom(srcblk, lblock);
 
 		if (error_action == TFC_ERRACT_SYNC) wrpos = tfc_fdgetpos(fd);
 _wagain:	lio = xwrite(fd, pblk, lrem);
diff --git a/tfc_signal.c b/tfc_signal.c
index 1e02534..aaacb2b 100644
--- a/tfc_signal.c
+++ b/tfc_signal.c
@@ -66,6 +66,7 @@ void print_crypt_status(int signal)
 		case TFC_DO_DECRYPT: oper_mode = "decrypted"; break;
 		default:
 			if (ctr_mode == TFC_MODE_PLAIN) oper_mode = "written";
+			else if (ctr_mode == TFC_MODE_XOR) oper_mode = "xored";
 			else if (ctr_mode == TFC_MODE_SKSUM) oper_mode = "hashed";
 			else oper_mode = NULL;
 			break;
diff --git a/tfcrypt.c b/tfcrypt.c
index 45438cb..a540db4 100644
--- a/tfcrypt.c
+++ b/tfcrypt.c
@@ -130,6 +130,7 @@ static void say_hint(const void *data, size_t szdata, const char *prompt)
 
 int main(int argc, char **argv)
 {
+	tfc_yesno flipfd;
 	int c;
 	double td;
 	char *s, *d, *t, *stoi;
@@ -152,12 +153,18 @@ _baddfname:
 
 	if (!strcmp(progname, "iotool")) {
 		do_edcrypt = TFC_DO_PLAIN;
-		password = YES;
 		ctr_mode = TFC_MODE_PLAIN;
 	}
 
+	if (!strcmp(progname, "xor")) {
+		do_edcrypt = TFC_DO_PLAIN;
+		ctr_mode = TFC_MODE_XOR;
+		/* xor: default to stdin if invoked without args */
+		kfd = 0;
+	}
+
 	opterr = 0;
-	while ((c = getopt(argc, argv, "L:s:aU:C:r:K:t:Pkzxc:l:qedn:vV:pwE:o:O:S:AmuM:R:Z:WHD:")) != -1) {
+	while ((c = getopt(argc, argv, "L:s:aU:C:r:K:t:PXkzxc:l:qedn:vV:pwE:o:O:S:AmuM:R:Z:WHD:")) != -1) {
 		switch (c) {
 			case 'L':
 				read_defaults(optarg, NO);
@@ -218,9 +225,14 @@ _baddfname:
 				else xerror(NO, YES, YES, "%s: invalid mode of operation", optarg);
 				break;
 			case 'P':
+			case 'X':
 				do_edcrypt = TFC_DO_PLAIN;
-				password = YES;
-				ctr_mode = TFC_MODE_PLAIN;
+				if (c == 'X') {
+					ctr_mode = TFC_MODE_XOR;
+					/* xor: default to stdin if invoked without args */
+					kfd = 0;
+				}
+				else ctr_mode = TFC_MODE_PLAIN;
 				break;
 			case 'e':
 				if (do_edcrypt != TFC_DO_PLAIN) do_edcrypt = TFC_DO_ENCRYPT;
@@ -404,7 +416,7 @@ _baddfname:
 							"%s: invalid iseek value", s);
 						}
 						else iseek = tfc_modifysize(iseek, strchr(s, ':'));
-						if (ctr_mode != TFC_MODE_PLAIN && iseek % TF_BLOCK_SIZE)
+						if (do_edcrypt != TFC_DO_PLAIN && iseek % TF_BLOCK_SIZE)
 							xerror(NO, YES, YES,
 								"%s: not round to TF block size "
 								"of %u bytes",
@@ -474,7 +486,7 @@ _baddfname:
 							"%s: invalid iseek value", s);
 						}
 						else iseek = tfc_modifysize(iseek, strchr(s, ':'));
-						if (ctr_mode != TFC_MODE_PLAIN && iseek % TF_BLOCK_SIZE)
+						if (do_edcrypt != TFC_DO_PLAIN && iseek % TF_BLOCK_SIZE)
 							xerror(NO, YES, YES,
 								"%s: not round to TF block size "
 								"of %u bytes",
@@ -675,9 +687,8 @@ _baddfname:
 		xerror(NO, YES, YES, "Cannot encrypt and read CTR from source!");
 	if (overwrite_source && counter_opt == TFC_CTR_RAND)
 		xerror(NO, YES, YES, "Cannot embed a CTR into file when overwriting it!");
-	if (ctr_mode == TFC_MODE_PLAIN
-	&& (do_edcrypt || do_mac || rawkey
-	|| mackey_opt || counter_opt || counter_file))
+	if (do_edcrypt == TFC_DO_PLAIN
+	&& (do_mac || saltf || rawkey || mackey_opt || counter_opt || counter_file))
 		xerror(NO, YES, YES, "Encryption facility is disabled when in plain IO mode.");
 
 	errno = 0;
@@ -777,10 +788,18 @@ _mkragain:		lio = xread(mkfd, pblk, lrem);
 	idx = optind;
 
 	if (argv[idx]) {
-		if (password || rawkey > TFC_RAWKEY_KEYFILE) goto _nokeyfd;
+		if ((do_edcrypt == TFC_DO_PLAIN && ctr_mode == TFC_MODE_PLAIN)
+		|| password
+		|| rawkey > TFC_RAWKEY_KEYFILE) goto _nokeyfd;
 		if (!strcmp(argv[idx], "-")) kfd = 0;
 		else kfd = xopen(argv[idx], O_RDONLY | O_LARGEFILE);
 
+		if (do_edcrypt == TFC_DO_PLAIN && ctr_mode == TFC_MODE_XOR) {
+			/* out: don't erase kfname if xor */
+			idx++;
+			goto _nokeyfd;
+		}
+
 		lio = strnlen(argv[idx], PATH_MAX);
 		memset(argv[idx], '*', lio);
 
@@ -880,7 +899,7 @@ _ctrskip1:
 			xerror(ignore_seek_errors, NO, NO, "%s: seek failed", srcfname);
 	}
 
-	if (ctr_mode == TFC_MODE_PLAIN) goto _plain;
+	if (do_edcrypt == TFC_DO_PLAIN) goto _plain;
 
 	if (verbose) tfc_esay("%s: hashing password", tfc_format_pid(progname));
 
@@ -1181,20 +1200,23 @@ _decrypt_again_vrfy2:
 		memset(svctr, 0, TF_BLOCK_SIZE);
 	}
 
+#define FLFD(x, y) (flipfd ? y : x)
 _nodecrypt_again_vrfy2:
 	loopcnt = 1;
 	errno = 0;
 	do_stop = NO;
+	flipfd = NO;
 	while (1) {
 		if (do_stop) break;
+		if (ctr_mode == TFC_MODE_XOR) flipfd = NO;
 		pblk = srcblk;
-		ldone = 0;
+_nextblk:	ldone = 0;
 		lrem = lblock = blk_len_adj(maxlen, total_processed_src, blksize);
-		if (error_action == TFC_ERRACT_SYNC) rdpos = tfc_fdgetpos(sfd);
-_ragain:	lio = xread(sfd, pblk, lrem);
+		if (error_action == TFC_ERRACT_SYNC) rdpos = tfc_fdgetpos(FLFD(sfd, kfd));
+_ragain:	lio = xread(FLFD(sfd, kfd), pblk, lrem);
 		if (lio == 0) {
-			if ((do_read_loops != 0 && sfd != 0) && (loopcnt < do_read_loops)) {
-				lseek(sfd, 0L, SEEK_SET);
+			if ((do_read_loops != 0 && FLFD(sfd, kfd) != 0) && (loopcnt < do_read_loops)) {
+				lseek(FLFD(sfd, kfd), 0L, SEEK_SET);
 				loopcnt++;
 				goto _ragain;
 			}
@@ -1212,8 +1234,8 @@ _ragain:	lio = xread(sfd, pblk, lrem);
 					xerror(YES, NO, NO, "%s", srcfname);
 					lio = ldone = lrem = lblock;
 					memset(srcblk, 0, lio);
-					if (rdpos == NOFSIZE) lseek(sfd, lio, SEEK_CUR);
-					else lseek(sfd, rdpos + lio, SEEK_SET);
+					if (rdpos == NOFSIZE) lseek(FLFD(sfd, kfd), lio, SEEK_CUR);
+					else lseek(FLFD(sfd, kfd), rdpos + lio, SEEK_SET);
 					break;
 				default: xerror(NO, NO, NO, "%s", srcfname); break;
 			}
@@ -1232,6 +1254,13 @@ _ragain:	lio = xread(sfd, pblk, lrem);
 			memset(srcblk+orig, 0, sizeof(srcblk)-orig);
 		}
 
+		if (ctr_mode == TFC_MODE_XOR && flipfd == NO) {
+			if (do_stop) blksize = ldone;
+			flipfd = YES;
+			pblk = dstblk;
+			goto _nextblk;
+		}
+
 		if (do_mac == TFC_MAC_SIGN) skein_update(&sk, srcblk, ldone);
 
 		if (ctr_mode == TFC_MODE_CTR) tf_ctr_crypt(key, ctr, dstblk, srcblk, ldone);
@@ -1256,6 +1285,9 @@ _ragain:	lio = xread(sfd, pblk, lrem);
 		else if (ctr_mode == TFC_MODE_PLAIN)
 			memcpy(dstblk, srcblk, ldone);
 
+		else if (ctr_mode == TFC_MODE_XOR)
+			xor_block(dstblk, srcblk, ldone);
+
 		if (do_mac >= TFC_MAC_VRFY) skein_update(&sk, dstblk, ldone);
 		if (do_mac >= TFC_MAC_JUST_VRFY) goto _nowrite;
 
diff --git a/tfcrypt.h b/tfcrypt.h
index ad12ef8..2dd2c68 100644
--- a/tfcrypt.h
+++ b/tfcrypt.h
@@ -233,7 +233,7 @@ enum { TFC_MACKEY_RAWKEY = 1, TFC_MACKEY_PASSWORD, TFC_MACKEY_FILE };
 enum { TFC_RAWKEY_KEYFILE = 1, TFC_RAWKEY_ASKSTR, TFC_RAWKEY_ASKHEX };
 enum { TFC_OUTFMT_HEX = 1, TFC_OUTFMT_B64, TFC_OUTFMT_RAW };
 enum {
-	TFC_MODE_SKSUM = -2, TFC_MODE_PLAIN = -1, TFC_MODE_CTR = 1,
+	TFC_MODE_SKSUM = -3, TFC_MODE_XOR = -2, TFC_MODE_PLAIN = -1, TFC_MODE_CTR = 1,
 	TFC_MODE_STREAM, TFC_MODE_XTS, TFC_MODE_ECB, TFC_MODE_CBC, TFC_MODE_PCBC
 };
 enum { TFC_CTR_SHOW = 1, TFC_CTR_HEAD, TFC_CTR_RAND, TFC_CTR_ZERO, TFC_CTR_SSET };