From: Andrey Rys <rys@lynxlynx.ru>
Date: Thu, 29 Nov 2018 07:46:28 +0000 (+0700)
Subject: Salt user keys or passwords.
X-Git-Url: https://jxself.org/git/?a=commitdiff_plain;h=add1a38544028f7f763b0ccf9ac354e8b45bec23;p=tfcrypt.git

Salt user keys or passwords.

Secretizing turns value was not enough, so it was decided
to add salt value which maybe hardcoded or loaded before key generation.
---

diff --git a/VERSION b/VERSION
index 0cfbf08..00750ed 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2
+3
diff --git a/tfc_error.c b/tfc_error.c
index 7c001da..048c0bb 100644
--- a/tfc_error.c
+++ b/tfc_error.c
@@ -151,6 +151,8 @@ void usage(void)
 	tfc_say("convert encrypted data into ASCII format to ease transmission.");
 	tfc_say("\n");
 	tfc_say("  -e, -d: encrypt, decrypt (it maybe required).");
+	tfc_say("  -s <file>: load tfcrypt salt from file.");
+	tfc_say("  -s disable: disable key salting at all.");
 	tfc_say("  -p: instead of using key, ask for password.");
 	tfc_say("  -k: use raw (%u byte) key instead of deriving it from arbitrary data.", TFC_U(TF_KEY_SIZE));
 	tfc_say("  -z: ask for key in plain C string form through password asker.");
diff --git a/tfc_vars.c b/tfc_vars.c
index 7f78b84..4986334 100644
--- a/tfc_vars.c
+++ b/tfc_vars.c
@@ -27,14 +27,11 @@
  */
 
 #include "tfcrypt.h"
+#include "tfcrypt_defs.h"
 
 char *progname;
 int exitcode;
 
-size_t nr_turns = TFC_NR_TURNS;
-int ctr_mode = TFC_CTR_MODE;
-size_t macbits = TF_MAX_BITS;
-
 tfc_byte key[TF_KEY_SIZE], ctr[TF_BLOCK_SIZE], xtskey[TF_KEY_SIZE], mackey[TF_FROM_BITS(TF_MAX_BITS)];
 struct skein sk;
 struct tfe_stream tfe;
@@ -67,7 +64,7 @@ tfc_yesno catch_all_errors, password, overwrite_source, do_fsync, do_pad, do_tfc
 tfc_yesno do_preserve_time, do_stats_in_gibs, do_statline_dynamic = YES, do_less_stats;
 tfc_yesno no_repeat, do_full_hexdump = YES, verbose, statline_was_shown;
 char *srcfname = TFC_STDIN_NAME, *dstfname = TFC_STDOUT_NAME, *do_mac_file, *counter_file, *sksum_hashlist_file;
-char *genkeyf, *mackeyf, *tweakf;
+char *saltf, *genkeyf, *mackeyf, *tweakf;
 char *pw_prompt, *mac_pw_prompt;
 tfc_useconds status_timer, bench_timer;
 tfc_useconds current_time, delta_time;
diff --git a/tfcrypt.c b/tfcrypt.c
index 6e30bc6..c544cfd 100644
--- a/tfcrypt.c
+++ b/tfcrypt.c
@@ -63,8 +63,11 @@ int main(int argc, char **argv)
 	if (!isatty(2)) do_statline_dynamic = NO;
 
 	opterr = 0;
-	while ((c = getopt(argc, argv, "aU:C:r:K:t:TPkzxc:l:qedn:vV:pwE:O:S:AmM:R:Z:WHD:")) != -1) {
+	while ((c = getopt(argc, argv, "s:aU:C:r:K:t:TPkzxc:l:qedn:vV:pwE:O:S:AmM:R:Z:WHD:")) != -1) {
 		switch (c) {
+			case 's':
+				saltf = optarg;
+				break;
 			case 'r':
 				randsource = optarg;
 				break;
@@ -143,6 +146,7 @@ int main(int argc, char **argv)
 				tweakf = optarg;
 				break;
 			case 'T':
+				tfc_saltsz = 0;
 				do_tfcrypt1 = YES;
 				break;
 			case 'l':
@@ -466,6 +470,23 @@ int main(int argc, char **argv)
 	errno = 0;
 	do_stop = NO;
 
+	if (saltf) {
+		int saltfd;
+
+		memset(tfc_salt, 0, TFC_MAX_SALT);
+		tfc_saltsz = 0;
+		if (!strcasecmp(saltf, "disable")) goto _nosalt;
+
+		if (!strcmp(saltf, "-")) saltfd = 0;
+		else saltfd = open(saltf, O_RDONLY | O_LARGEFILE);
+		if (saltfd == -1) xerror(NO, NO, YES, "%s", saltf);
+		lio = read(saltfd, tfc_salt, TFC_MAX_SALT - TF_FROM_BITS(TFC_KEY_BITS));
+		if (lio == NOSIZE) xerror(NO, NO, YES, "%s", saltf);
+		tfc_saltsz = lio;
+		xclose(saltfd);
+	}
+
+_nosalt:
 	if (mackey_opt == TFC_MACKEY_FILE && mackeyf) {
 		int mkfd = -1;
 		tfc_yesno do_stop;
@@ -786,9 +807,14 @@ _pwdagain:	memset(&getps, 0, sizeof(struct getpasswd_state));
 			xerror(NO, NO, YES, "hashing key");
 	}
 
-	if (nr_turns > 1 && rawkey == NO) {
-		for (x = 0; x < nr_turns; x++)
+	if (rawkey == NO) {
+		if (tfc_saltsz > 0) {
+			memcpy(tfc_salt+tfc_saltsz, key, TF_FROM_BITS(TFC_KEY_BITS));
+			skein(key, TFC_KEY_BITS, mackey_opt ? mackey : NULL, tfc_salt, tfc_saltsz+TF_FROM_BITS(TFC_KEY_BITS));
+		}
+		if (nr_turns > 1) for (x = 0; x < nr_turns; x++)
 			skein(key, TFC_KEY_BITS, mackey_opt ? mackey : NULL, key, TF_FROM_BITS(TFC_KEY_BITS));
+		memset(tfc_salt, 0, TFC_MAX_SALT);
 	}
 
 	if (ctr_mode == TFC_MODE_XTS && rawkey == NO) {
diff --git a/tfcrypt.h b/tfcrypt.h
index 9b1caf0..fcc75ee 100644
--- a/tfcrypt.h
+++ b/tfcrypt.h
@@ -72,18 +72,14 @@ typedef TF_BYTE_TYPE tfc_byte;
 typedef unsigned long long tfc_fsize;
 typedef unsigned long long tfc_useconds;
 
-#ifndef TFC_NR_TURNS
-#define TFC_NR_TURNS 262144
-#endif
-
-#ifndef TFC_CTR_MODE
-#define TFC_CTR_MODE TFC_MODE_XTS
-#endif
-
 #ifndef TFC_BLKSIZE
 #define TFC_BLKSIZE 65536
 #endif
 
+#ifndef TFC_MAX_SALT
+#define TFC_MAX_SALT (2048 + TF_KEY_SIZE)
+#endif
+
 #ifndef TFC_XTSBLOCKS
 #define TFC_XTSBLOCKS 32
 #endif
@@ -117,11 +113,14 @@ int xmhexdump(int to, const void *data, size_t szdata, int hgroup, int hexstr, i
 #define mhexdump(data, szdata, group, newline) xmhexdump(1, data, szdata, group, do_full_hexdump, newline)
 #define mehexdump(data, szdata, group, newline) xmhexdump(2, data, szdata, group, do_full_hexdump, newline)
 
-extern char *progname;
-extern int exitcode;
 extern size_t nr_turns;
 extern int ctr_mode;
 extern size_t macbits;
+extern size_t tfc_saltsz;
+extern tfc_byte tfc_salt[TFC_MAX_SALT];
+
+extern char *progname;
+extern int exitcode;
 extern tfc_byte key[TF_KEY_SIZE], ctr[TF_BLOCK_SIZE], xtskey[TF_KEY_SIZE], mackey[TF_FROM_BITS(TF_MAX_BITS)];
 extern struct skein sk;
 extern struct tfe_stream tfe;
@@ -148,7 +147,7 @@ extern tfc_yesno catch_all_errors, password, overwrite_source, do_fsync, do_pad,
 extern tfc_yesno do_preserve_time, do_stats_in_gibs, do_statline_dynamic, do_less_stats;
 extern tfc_yesno no_repeat, do_full_hexdump, verbose, statline_was_shown;
 extern char *srcfname, *dstfname, *do_mac_file, *counter_file, *sksum_hashlist_file;
-extern char *genkeyf, *mackeyf, *tweakf;
+extern char *saltf, *genkeyf, *mackeyf, *tweakf;
 extern char *pw_prompt, *mac_pw_prompt;
 extern tfc_useconds status_timer, bench_timer;
 extern tfc_useconds current_time, delta_time;
diff --git a/tfcrypt_defs.h b/tfcrypt_defs.h
new file mode 100644
index 0000000..28db479
--- /dev/null
+++ b/tfcrypt_defs.h
@@ -0,0 +1,15 @@
+#ifndef _TFCRYPT_DEFAULTS_HEADER
+#define _TFCRYPT_DEFAULTS_HEADER
+
+size_t nr_turns = 262144;
+int ctr_mode = TFC_MODE_XTS;
+size_t macbits = TF_MAX_BITS;
+size_t tfc_saltsz = 32;
+tfc_byte tfc_salt[TFC_MAX_SALT] = {
+	0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
+	0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
+	0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
+	0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
+};
+
+#endif