-o logfile: logging to separate logfile instead of stderr.
[tfcrypt.git] / tfcrypt.c
index 8608cf16011399202e66f08b8855211c6368a56e..b6bbe73de3cd3f3d38497fe2c8e11cd2697af735 100644 (file)
--- a/tfcrypt.c
+++ b/tfcrypt.c
@@ -2,7 +2,7 @@
  * tfcrypt -- high security Threefish encryption tool.
  *
  * tfcrypt is copyrighted:
- * Copyright (C) 2012-2018 Andrey Rys. All rights reserved.
+ * Copyright (C) 2012-2019 Andrey Rys. All rights reserved.
  *
  * tfcrypt is licensed to you under the terms of std. MIT/X11 license:
  *
 
 #include "tfcrypt.h"
 
+static tfc_byte svctr[TF_BLOCK_SIZE];
+
+static void open_log(const char *logfile)
+{
+       int fd;
+
+       fd = open(logfile, O_WRONLY | O_CREAT | O_LARGEFILE | O_TRUNC, 0666);
+       if (fd == -1) xerror(NO, NO, YES, "%s", logfile);
+       xclose(2);
+       if (dup2(fd, 2) == -1) xerror(NO, NO, YES, "dup2(%d, 2) for %s", fd, logfile);
+       xclose(fd);
+       do_statline_dynamic = NO;
+}
+
 static int getps_filter(struct getpasswd_state *getps, char chr, size_t pos)
 {
        if (chr == '\x03') {
@@ -51,20 +65,96 @@ static int getps_hex_filter(struct getpasswd_state *getps, char chr, size_t pos)
        return 0;
 }
 
+static inline int isctrlchr(int c)
+{
+       if (c == 9) return 0;
+       if (c >= 0 && c <= 31) return 1;
+       if (c == 127) return 1;
+       return 0;
+}
+
+static int getps_plain_filter(struct getpasswd_state *getps, char chr, size_t pos)
+{
+       int x;
+
+       x = getps_filter(getps, chr, pos);
+       if (x != 1) return x;
+
+       if (pos < getps->pwlen && !isctrlchr(chr))
+               write(getps->efd, &chr, sizeof(char));
+       return 1;
+}
+
+static int getps_plain_hex_filter(struct getpasswd_state *getps, char chr, size_t pos)
+{
+       int x;
+
+       x = getps_hex_filter(getps, chr, pos);
+       if (x != 1) return x;
+
+       if (pos < getps->pwlen && !isctrlchr(chr))
+               write(getps->efd, &chr, sizeof(char));
+       return 1;
+}
+
+static void make_hint(void *hint, size_t szhint, const void *data, size_t szdata)
+{
+       char t[TF_FROM_BITS(TF_MAX_BITS)];
+
+       skein(t, TF_MAX_BITS, NULL, data, szdata);
+       xor_shrink(hint, szhint, t, sizeof(t));
+       memset(t, 0, sizeof(t));
+}
+
+static void raw_say_hint(void *hint, size_t szhint, const void *data, size_t szdata, const char *prompt)
+{
+       make_hint(hint, szhint, data, szdata);
+       if (prompt) tfc_nfsay(stderr, "%s: ", prompt);
+       mehexdump(hint, szhint, szhint, 1);
+       memset(hint, 0, szhint);
+}
+
+static void say_hint(const void *data, size_t szdata, const char *prompt)
+{
+       char t[TF_SIZE_UNIT];
+       raw_say_hint(t, TF_SIZE_UNIT, data, szdata, prompt);
+       /* t[] is erased (automatically) */
+}
+
 int main(int argc, char **argv)
 {
        int c;
        double td;
        char *s, *d, *t, *stoi;
        size_t x, n;
+       tfc_fsize rwd;
 
        progname = basename(argv[0]);
 
        if (!isatty(2)) do_statline_dynamic = NO;
 
+       s = (char *)srcblk;
+       d = getenv("HOME");
+       if (!d) d = "";
+       n = PATH_MAX > sizeof(srcblk) ? sizeof(srcblk) : PATH_MAX;
+       if (xstrlcpy(s, d, n) >= n) goto _baddfname;
+       if (xstrlcat(s, "/.tfcrypt.defs", n) >= n) goto _baddfname;
+       read_defaults(s, YES);
+_baddfname:
+       memset(s, 0, n);
+
+       if (!strcmp(progname, "iotool")) {
+               do_edcrypt = TFC_DO_PLAIN;
+               password = YES;
+               ctr_mode = TFC_MODE_PLAIN;
+       }
+
        opterr = 0;
-       while ((c = getopt(argc, argv, "s:aU:C:r:K:t:TPkzxc:l:qedn:vV:pwE:O:S:AmM:R:Z:WHD:")) != -1) {
+       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) {
                switch (c) {
+                       case 'L':
+                               read_defaults(optarg, NO);
+                               break;
                        case 's':
                                saltf = optarg;
                                break;
@@ -78,6 +168,31 @@ int main(int argc, char **argv)
                                        counter_opt = TFC_CTR_HEAD;
                                else if (!strcasecmp(optarg, "rand"))
                                        counter_opt = TFC_CTR_RAND;
+                               else if (!strcasecmp(optarg, "zero"))
+                                       counter_opt = TFC_CTR_ZERO;
+                               else if (strchr(optarg, ':')) {
+                                       char *ss, chr;
+
+                                       counter_opt = TFC_CTR_SSET;
+                                       n = sizeof(ctr);
+
+                                       s = d = optarg; t = NULL;
+                                       while ((s = strtok_r(d, ",", &t))) {
+                                               if (d) d = NULL;
+
+                                               if (n == 0) break;
+                                               ss = strchr(s, ':');
+                                               if (!ss) continue;
+                                               *ss = 0; ss++;
+                                               chr = (char)strtoul(s, &stoi, 16);
+                                               if (!str_empty(stoi)) continue;
+                                               x = (size_t)strtoul(ss, &stoi, 10);
+                                               if (!str_empty(stoi)) continue;
+                                               if (x > n) x = n;
+                                               memset(ctr+(sizeof(ctr)-n), (int)chr, x);
+                                               n -= x;
+                                       }
+                               }
                                else counter_file = sksum_hashlist_file = optarg;
                                break;
                        case 'C':
@@ -101,10 +216,10 @@ int main(int argc, char **argv)
                                ctr_mode = TFC_MODE_PLAIN;
                                break;
                        case 'e':
-                               do_edcrypt = TFC_DO_ENCRYPT;
+                               if (do_edcrypt != TFC_DO_PLAIN) do_edcrypt = TFC_DO_ENCRYPT;
                                break;
                        case 'd':
-                               do_edcrypt = TFC_DO_DECRYPT;
+                               if (do_edcrypt != TFC_DO_PLAIN) do_edcrypt = TFC_DO_DECRYPT;
                                break;
                        case 'D':
                                macbits = strtoul(optarg, &stoi, 10);
@@ -144,10 +259,7 @@ int main(int argc, char **argv)
                                break;
                        case 't':
                                tweakf = optarg;
-                               break;
-                       case 'T':
-                               tfc_saltsz = 0;
-                               do_tfcrypt1 = YES;
+                               do_full_key = NO;
                                break;
                        case 'l':
                                if (maxlen != NOFSIZE) break;
@@ -171,6 +283,10 @@ int main(int argc, char **argv)
                                        catch_all_errors = YES;
                                        break;
                                }
+                               if (!strcmp(optarg, "xseek")) {
+                                       ignore_seek_errors = YES;
+                                       break;
+                               }
                                if (!strcmp(optarg, "exit"))
                                        error_action = TFC_ERRACT_EXIT;
                                else if (!strncmp(optarg, "cont", 4))
@@ -181,6 +297,9 @@ int main(int argc, char **argv)
                                        error_action = TFC_ERRACT_LSYNC;
                                else xerror(NO, YES, YES, "invalid error action %s specified", optarg);
                                break;
+                       case 'o':
+                               open_log(optarg);
+                               break;
                        case 'O':
                                s = d = optarg; t = NULL;
                                while ((s = strtok_r(d, ",", &t))) {
@@ -209,6 +328,12 @@ int main(int argc, char **argv)
                                                mac_pw_prompt = s+10;
                                        else if (!strcmp(s, "shorthex"))
                                                do_full_hexdump = NO;
+                                       else if (!strcmp(s, "fullkey"))
+                                               do_full_key = YES;
+                                       else if (!strcmp(s, "showsecrets"))
+                                               show_secrets = YES;
+                                       else if (!strncmp(s, "logfile", 7) && *(s+7) == '=')
+                                               open_log(s+8);
                                        else if (!strncmp(s, "iobs", 4) && *(s+4) == '=') {
                                                s += 5;
                                                blksize = (size_t)tfc_humanfsize(s, &stoi);
@@ -324,17 +449,47 @@ int main(int argc, char **argv)
                                                if (counter_opt == TFC_CTR_HEAD)
                                                        maxlen += TF_BLOCK_SIZE;
                                        }
+                                       else if (!strncmp(s, "ftrunc", 6) && *(s+6) == '=') {
+                                               s += 7;
+                                               if (!strcmp(s, "tail")) {
+                                                       do_ftrunc = TFC_FTRUNC_TAIL;
+                                                       ftrunc_dfd = NOFSIZE;
+                                               }
+                                               else {
+                                                       do_ftrunc = TFC_DO_FTRUNC;
+                                                       ftrunc_dfd = tfc_humanfsize(s, &stoi);
+                                                       if (!str_empty(stoi)) {
+                                                               ftrunc_dfd = tfc_fnamesize(s, YES);
+                                                               ftrunc_dfd = tfc_modifysize(ftrunc_dfd, strchr(s, ':'));
+                                                               if (ftrunc_dfd == NOFSIZE) xerror(NO, YES, YES,
+                                                               "%s: invalid ftrunc value", s);
+                                                       }
+                                                       else ftrunc_dfd = tfc_modifysize(ftrunc_dfd, strchr(s, ':'));
+                                               }
+                                       }
                                        else if (!strncmp(s, "xkey", 4) && *(s+4) == '=') {
                                                s += 5;
                                                maxkeylen = tfc_humanfsize(s, &stoi);
                                                if (!str_empty(stoi)) {
-                                                       maxkeylen = (size_t)tfc_fnamesize(s, YES);
-                                                       maxkeylen = (size_t)tfc_modifysize((tfc_fsize)maxkeylen, strchr(s, ':'));
+                                                       maxkeylen = tfc_fnamesize(s, YES);
+                                                       maxkeylen = tfc_modifysize(maxkeylen, strchr(s, ':'));
                                                        if (maxkeylen == NOSIZE)
                                                                xerror(NO, YES, YES,
                                                                "%s: invalid key length value", s);
                                                }
-                                               else maxkeylen = (size_t)tfc_modifysize((tfc_fsize)maxkeylen, strchr(s, ':'));
+                                               else maxkeylen = tfc_modifysize(maxkeylen, strchr(s, ':'));
+                                       }
+                                       else if (!strncmp(s, "okey", 4) && *(s+4) == '=') {
+                                               s += 5;
+                                               keyoffset = tfc_humanfsize(s, &stoi);
+                                               if (!str_empty(stoi)) {
+                                                       keyoffset = tfc_fnamesize(s, YES);
+                                                       keyoffset = tfc_modifysize(keyoffset, strchr(s, ':'));
+                                                       if (keyoffset == NOFSIZE)
+                                                               xerror(NO, YES, YES,
+                                                               "%s: invalid key offset value", s);
+                                               }
+                                               else keyoffset = tfc_modifysize(keyoffset, strchr(s, ':'));
                                        }
                                        else if (!strncmp(s, "xctr", 4) && *(s+4) == '=') {
                                                s += 5;
@@ -366,9 +521,11 @@ int main(int argc, char **argv)
                                        do_mac_file = optarg;
                                break;
                        case 'm':
+                       case 'u':
                                if (do_mac != TFC_MAC_VRFY)
                                        xerror(NO, YES, YES, "signature source was not specified");
                                do_mac = TFC_MAC_JUST_VRFY;
+                               if (c == 'u') do_mac = TFC_MAC_JUST_VRFY2;
                                break;
                        case 'R':
                        case 'Z':
@@ -413,6 +570,7 @@ int main(int argc, char **argv)
                        case 'q':
                                quiet = YES;
                                verbose = NO;
+                               do_full_hexdump = NO;
                                status_timer = 0;
                                break;
                        case 'v':
@@ -462,8 +620,6 @@ int main(int argc, char **argv)
                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 (tweakf && do_tfcrypt1 == NO)
-               xerror(NO, YES, YES, "Use -T with -t tweakfile to enable old tfcrypt mode!");
        if (ctr_mode == TFC_MODE_PLAIN
        && (do_edcrypt || do_mac || rawkey
        || mackey_opt || counter_opt || counter_file))
@@ -507,7 +663,7 @@ _nosalt:
                        lrem = lblock = sizeof(tmpdata);
                        if (error_action == TFC_ERRACT_SYNC) rdpos = tfc_fdgetpos(mkfd);
 _mkragain:             lio = xread(mkfd, pblk, lrem);
-                       if (lio == 0) do_stop = YES;
+                       if (lio == 0 && do_stop == NO) do_stop = YES;
                        if (lio != NOSIZE) ldone += lio;
                        else {
                                if (errno != EIO && catch_all_errors != YES)
@@ -544,20 +700,14 @@ _mkragain:                lio = xread(mkfd, pblk, lrem);
                getps.passwd = pwdask;
                getps.pwlen = sizeof(pwdask)-1;
                getps.echo = mac_pw_prompt ? mac_pw_prompt : "Enter MAC password: ";
-               getps.charfilter = getps_filter;
-               getps.maskchar = 'x';
+               getps.charfilter = (show_secrets == YES) ? getps_plain_filter : getps_filter;
+               getps.maskchar = (show_secrets == YES) ? 0 : 'x';
                getps.flags = GETP_WAITFILL;
                n = xgetpasswd(&getps);
                if (n == NOSIZE) xerror(NO, NO, YES, "getting MAC password");
                if (n == ((size_t)-2)) xexit(1);
+               if (verbose) say_hint(pwdask, n, "MAC password hint");
                skein(mackey, TF_MAX_BITS, NULL, pwdask, n);
-               if (verbose) {
-                       skein(tmpdata, TF_MAX_BITS, NULL, mackey, TF_FROM_BITS(TF_MAX_BITS));
-                       xor_shrink(tmpdata+TF_FROM_BITS(TF_MAX_BITS), TF_SIZE_UNIT, tmpdata, TF_FROM_BITS(TF_MAX_BITS));
-                       tfc_nfsay(stderr, "MAC password hint: ");
-                       mehexdump(tmpdata+TF_FROM_BITS(TF_MAX_BITS), TF_SIZE_UNIT, TF_SIZE_UNIT, 1);
-                       memset(tmpdata, 0, sizeof(tmpdata));
-               }
        }
 
        
@@ -587,16 +737,16 @@ _mkragain:                lio = xread(mkfd, pblk, lrem);
        else password = YES;
 
        errno = 0;
-       if (do_tfcrypt1 == YES && tweakf) {
+       if (do_full_key == NO && tweakf) {
                int twfd;
 
                if (!strcmp(tweakf, "-")) twfd = 0;
                else twfd = open(tweakf, O_RDONLY | O_LARGEFILE);
                if (twfd == -1) xerror(NO, NO, YES, "%s", tweakf);
-               lio = ldone = xread(twfd, key+TF_FROM_BITS(TF_MAX_BITS)+TF_SIZE_UNIT, 2*TF_SIZE_UNIT);
+               lio = ldone = xread(twfd, tweak, TF_TWEAK_SIZE);
                if (lio == NOSIZE) xerror(NO, NO, YES, "%s", tweakf);
-               if (ldone < 2*TF_SIZE_UNIT)
-                       xerror(NO, NO, YES, "%s: %zu bytes tweak required", tweakf, 2*TF_SIZE_UNIT);
+               if (ldone < TF_TWEAK_SIZE)
+                       xerror(NO, NO, YES, "%s: %zu bytes tweak required", tweakf, TF_TWEAK_SIZE);
                xclose(twfd);
        }
 
@@ -683,7 +833,7 @@ _ctrskip1:
                if (counter_opt == TFC_CTR_HEAD && ctr_mode != TFC_MODE_ECB)
                        iseek += ctrsz;
                if (lseek(sfd, iseek, SEEK_SET) == -1)
-                       xerror(YES, NO, NO, "%s: seek failed", srcfname);
+                       xerror(ignore_seek_errors, NO, NO, "%s: seek failed", srcfname);
        }
 
        if (ctr_mode == TFC_MODE_PLAIN) goto _plain;
@@ -739,12 +889,13 @@ _xts2keyaskstr:   memset(&getps, 0, sizeof(struct getpasswd_state));
                getps.passwd = (char *)pblk;
                getps.pwlen = n;
                getps.echo = pw_prompt ? pw_prompt : "Enter rawkey (str): ";
-               getps.charfilter = getps_filter;
-               getps.maskchar = 'x';
+               getps.charfilter = (show_secrets == YES) ? getps_plain_filter : getps_filter;
+               getps.maskchar = (show_secrets == YES) ? 0 : 'x';
                getps.flags = GETP_WAITFILL;
                n = xgetpasswd(&getps);
                if (n == NOSIZE) xerror(NO, NO, YES, "getting string rawkey");
                if (n == ((size_t)-2)) xexit(1);
+               if (verbose) say_hint(pblk, n, "Raw string key hint");
                if (ctr_mode == TFC_MODE_XTS) {
                        if (xtskeyset == NO) {
                                pblk = xtskey; n = sizeof(xtskey);
@@ -763,8 +914,8 @@ _rawkey_hex_again:
                getps.passwd = pwdask;
                getps.pwlen = (TF_FROM_BITS(TFC_KEY_BITS)*2);
                getps.echo = pw_prompt ? pw_prompt : "Enter rawkey (hex): ";
-               getps.charfilter = getps_hex_filter;
-               getps.maskchar = 'x';
+               getps.charfilter = (show_secrets == YES) ? getps_plain_hex_filter : getps_hex_filter;
+               getps.maskchar = (show_secrets == YES) ? 0 : 'x';
                getps.flags = GETP_WAITFILL;
                n = xgetpasswd(&getps);
                if (n == NOSIZE) xerror(NO, NO, YES, "getting hex rawkey");
@@ -775,6 +926,7 @@ _rawkey_hex_again:
                }
                hex2bin(pblk, pwdask);
                memset(pwdask, 0, sizeof(pwdask));
+               if (verbose) say_hint(pblk, n/2, "Raw hex key hint");
                if (ctr_mode == TFC_MODE_XTS) {
                        if (xtskeyset == NO) {
                                pblk = xtskey;
@@ -789,8 +941,8 @@ _pwdagain:  memset(&getps, 0, sizeof(struct getpasswd_state));
                getps.passwd = pwdask;
                getps.pwlen = sizeof(pwdask)-1;
                getps.echo = pw_prompt ? pw_prompt : "Enter password: ";
-               getps.charfilter = getps_filter;
-               getps.maskchar = 'x';
+               getps.charfilter = (show_secrets == YES) ? getps_plain_filter : getps_filter;
+               getps.maskchar = (show_secrets == YES) ? 0 : 'x';
                getps.flags = GETP_WAITFILL;
                n = xgetpasswd(&getps);
                if (n == NOSIZE) xerror(NO, NO, YES, "getting password");
@@ -809,12 +961,13 @@ _pwdagain:        memset(&getps, 0, sizeof(struct getpasswd_state));
                                goto _pwdagain;
                        }
                }
+               if (verbose) say_hint(pwdask, n, "Password hint");
                skein(key, TFC_KEY_BITS, mackey_opt ? mackey : NULL, pwdask, n);
                memset(pwdask, 0, sizeof(pwdask));
                memset(pwdagain, 0, sizeof(pwdagain));
        }
        else {
-               if (skeinfd(key, TFC_KEY_BITS, mackey_opt ? mackey : NULL, kfd, maxkeylen) != YES)
+               if (skeinfd(key, TFC_KEY_BITS, mackey_opt ? mackey : NULL, kfd, keyoffset, maxkeylen) != YES)
                        xerror(NO, NO, YES, "hashing key");
        }
 
@@ -883,25 +1036,26 @@ _xts2genkey:     if (xwrite(krfd, pblk, TF_FROM_BITS(TFC_KEY_BITS)) == NOSIZE) xerro
 
        tf_convkey(key);
        if (ctr_mode == TFC_MODE_XTS) tf_convkey(xtskey);
-       if (do_tfcrypt1 == YES) {
-               if (!tweakf) skein(key+TF_FROM_BITS(TF_MAX_BITS)+TF_SIZE_UNIT, 2*TF_UNIT_BITS, NULL, key, TF_FROM_BITS(TFC_KEY_BITS));
-               tf_key_tweak_compat(key);
+       if (do_full_key == NO) {
+               if (!tweakf) skein(tweak, TF_NR_TWEAK_BITS, NULL, key, TF_FROM_BITS(TFC_KEY_BITS));
+               tf_tweak_set(key, tweak);
        }
-       if (ctr_mode == TFC_MODE_STREAM) tfe_init_iv(&tfe, key, ctr);
        if (ctr_mode == TFC_MODE_ECB) goto _ctrskip2;
+
+       if (counter_opt == TFC_CTR_ZERO) memset(ctr, 0, ctrsz);
+
        tfc_data_to_words64(&iseek_blocks, sizeof(iseek_blocks));
        tf_ctr_set(ctr, &iseek_blocks, sizeof(iseek_blocks));
+       if (do_mac == TFC_MAC_JUST_VRFY2) memcpy(svctr, ctr, TF_BLOCK_SIZE);
 
-       switch (counter_opt) {
-               case TFC_CTR_SHOW:
-                       switch (do_outfmt) {
-                               case TFC_OUTFMT_B64: tfc_printbase64(stderr, ctr, ctrsz, YES); break;
-                               case TFC_OUTFMT_RAW: xwrite(2, ctr, ctrsz); break;
-                               case TFC_OUTFMT_HEX: mehexdump(ctr, ctrsz, ctrsz, YES); break;
-                       }
-                       break;
-               case TFC_CTR_RAND: tfc_getrandom(ctr, ctrsz); break;
+       if (counter_opt == TFC_CTR_SHOW) {
+               switch (do_outfmt) {
+                       case TFC_OUTFMT_B64: tfc_printbase64(stderr, ctr, ctrsz, YES); break;
+                       case TFC_OUTFMT_RAW: xwrite(2, ctr, ctrsz); break;
+                       case TFC_OUTFMT_HEX: mehexdump(ctr, ctrsz, ctrsz, YES); break;
+               }
        }
+       else if (counter_opt == TFC_CTR_RAND) tfc_getrandom(ctr, ctrsz);
 
 _ctrskip2:
        if (kfd != -1) {
@@ -926,7 +1080,7 @@ _plain:
 
        if (oseek) {
                if (lseek(dfd, oseek, SEEK_SET) == -1)
-                       xerror(YES, NO, NO, "%s: seek failed", dstfname);
+                       xerror(ignore_seek_errors, NO, NO, "%s: seek failed", dstfname);
        }
 
        for (x = 1; x < NSIG; x++) signal(x, SIG_IGN);
@@ -934,7 +1088,6 @@ _plain:
        sigact.sa_flags = SA_RESTART;
        sigact.sa_handler = print_crypt_status;
        sigaction(SIGUSR1, &sigact, NULL);
-       sigaction(SIGTSTP, &sigact, NULL);
        sigaction(SIGALRM, &sigact, NULL);
        if (status_timer) setup_next_alarm(status_timer);
        sigact.sa_handler = change_status_width;
@@ -945,11 +1098,14 @@ _plain:
                sigact.sa_handler = print_crypt_status;
                sigaction(SIGINT, &sigact, NULL);
                sigaction(SIGTERM, &sigact, NULL);
+               sigaction(SIGTSTP, &sigact, NULL);
        }
        else {
                sigact.sa_handler = exit_sigterm;
                sigaction(SIGINT, &sigact, NULL);
                sigaction(SIGTERM, &sigact, NULL);
+               sigact.sa_handler = handle_sigtstp;
+               sigaction(SIGTSTP, &sigact, NULL);
        }
        memset(&sigact, 0, sizeof(struct sigaction));
 
@@ -973,6 +1129,26 @@ _ctrwagain:       lio = xwrite(dfd, pblk, lrem);
                delta_processed += ldone;
        }
 
+       if (ctr_mode == TFC_MODE_STREAM) tfe_init_iv(&tfe, key, ctr);
+
+       if (do_mac == TFC_MAC_JUST_VRFY2) {
+               rwd = tfc_fdgetpos(sfd);
+               if (rwd == NOFSIZE) {
+                       tfc_esay("%s: WARNING: input is not seekable, disabling MAC testing mode", progname);
+                       do_mac = TFC_MAC_VRFY;
+               }
+               goto _nodecrypt_again_vrfy2;
+
+_decrypt_again_vrfy2:
+               if (lseek(sfd, (off_t)rwd, SEEK_SET) == ((off_t)-1)) {
+                       xerror(ignore_seek_errors, NO, YES, "MAC testing seek failed");
+               }
+               total_processed_src = rwd;
+               memcpy(ctr, svctr, TF_BLOCK_SIZE);
+               memset(svctr, 0, TF_BLOCK_SIZE);
+       }
+
+_nodecrypt_again_vrfy2:
        errno = 0;
        do_stop = NO;
        while (1) {
@@ -982,7 +1158,7 @@ _ctrwagain:        lio = xwrite(dfd, pblk, lrem);
                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 (lio == 0) do_stop = TFC_STOP_BEGAN;
+               if (lio == 0) do_stop = YES;
                if (lio != NOSIZE) ldone += lio;
                else {
                        if (errno != EIO && catch_all_errors != YES)
@@ -1042,7 +1218,7 @@ _ragain:  lio = xread(sfd, pblk, lrem);
 
                if (do_mac >= TFC_MAC_VRFY && ctr_mode < TFC_MODE_OCB)
                        skein_update(&sk, dstblk, ldone);
-               if (do_mac == TFC_MAC_JUST_VRFY) goto _nowrite;
+               if (do_mac >= TFC_MAC_JUST_VRFY) goto _nowrite;
 
                pblk = dstblk;
                lrem = ldone;
@@ -1056,14 +1232,16 @@ _wagain:        lio = xwrite(dfd, pblk, lrem);
                        lrem -= lio;
                        goto _wagain;
                }
+               total_written_dst += ldone;
 _nowrite:      total_processed_dst += ldone;
                delta_processed += ldone;
 
-               if (maxlen != NOFSIZE && total_processed_src >= maxlen) break;
+               if (maxlen != NOFSIZE && total_processed_src >= maxlen) {
+                       do_stop = YES;
+                       break;
+               }
        }
 
-       if (do_stop == TFC_STOP_FULL) goto _nomac;
-
        errno = 0;
        if (do_mac >= TFC_MAC_VRFY) {
                if (!do_mac_file) {
@@ -1139,10 +1317,18 @@ _macragain:             lio = xread(sfd, pblk, lrem);
                                        else mehexdump(macresult, TF_FROM_BITS(macbits), TF_FROM_BITS(macbits), YES);
                                }
                        }
+                       if (do_mac == TFC_MAC_JUST_VRFY2) {
+                               if (verbose) tfc_esay("%s: -u: MAC signature is valid, proceeding with decrypting it again", progname);
+                               do_mac = TFC_MAC_DROP;
+                               goto _decrypt_again_vrfy2;
+                       }
                }
                else {
-                       if (quiet == NO) tfc_esay("%s: signature is BAD: "
+                       if (quiet == NO) {
+                               tfc_esay("%s: signature is BAD: "
                                "wrong password, key, mode, or file is not signed", progname);
+                               if (do_mac == TFC_MAC_JUST_VRFY2) tfc_esay("%s: -u: MAC signature is invalid, not decrypting it again", progname);
+                       }
                        exitcode = 1;
                }
 
@@ -1208,12 +1394,7 @@ _macwagain:              lio = xwrite(dfd, pblk, lrem);
                memset(tmpdata, 0, sizeof(tmpdata));
        }
 
-_nomac:
-       if (verbose || status_timer || do_stop == TFC_STOP_FULL) print_crypt_status(0);
-
-       if (do_preserve_time) fcopy_matime(dfd, &s_stat);
-       xclose(sfd);
-       xclose(dfd);
+       if (verbose || status_timer || (do_stop == YES && quiet == NO)) print_crypt_status(0);
 
        xexit(exitcode);
        return -1;