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1 /*
2  * Author: Tatu Ylonen <ylo@cs.hut.fi>
3  * Copyright (c) 1994 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4  *                    All rights reserved
5  * Identity and host key generation and maintenance.
6  *
7  * As far as I am concerned, the code I have written for this software
8  * can be used freely for any purpose.  Any derived versions of this
9  * software must be clearly marked as such, and if the derived work is
10  * incompatible with the protocol description in the RFC file, it must be
11  * called by a name other than "ssh" or "Secure Shell".
12  */
13
14 #include "includes.h"
15 RCSID("$OpenBSD: ssh-keygen.c,v 1.31 2000/09/07 20:27:54 deraadt Exp $");
16
17 #include <openssl/evp.h>
18 #include <openssl/pem.h>
19 #include <openssl/rsa.h>
20 #include <openssl/dsa.h>
21
22 #include "ssh.h"
23 #include "xmalloc.h"
24 #include "key.h"
25 #include "rsa.h"
26 #include "dsa.h"
27 #include "authfile.h"
28 #include "uuencode.h"
29
30 /* Number of bits in the RSA/DSA key.  This value can be changed on the command line. */
31 int bits = 1024;
32
33 /*
34  * Flag indicating that we just want to change the passphrase.  This can be
35  * set on the command line.
36  */
37 int change_passphrase = 0;
38
39 /*
40  * Flag indicating that we just want to change the comment.  This can be set
41  * on the command line.
42  */
43 int change_comment = 0;
44
45 int quiet = 0;
46
47 /* Flag indicating that we just want to see the key fingerprint */
48 int print_fingerprint = 0;
49
50 /* The identity file name, given on the command line or entered by the user. */
51 char identity_file[1024];
52 int have_identity = 0;
53
54 /* This is set to the passphrase if given on the command line. */
55 char *identity_passphrase = NULL;
56
57 /* This is set to the new passphrase if given on the command line. */
58 char *identity_new_passphrase = NULL;
59
60 /* This is set to the new comment if given on the command line. */
61 char *identity_comment = NULL;
62
63 /* Dump public key file in format used by real and the original SSH 2 */
64 int convert_to_ssh2 = 0;
65 int convert_from_ssh2 = 0;
66 int print_public = 0;
67 int dsa_mode = 0;
68
69 /* argv0 */
70 #ifdef HAVE___PROGNAME
71 extern char *__progname;
72 #else /* HAVE___PROGNAME */
73 static const char *__progname = "ssh-keygen";
74 #endif /* HAVE___PROGNAME */
75
76 char hostname[MAXHOSTNAMELEN];
77
78 void
79 ask_filename(struct passwd *pw, const char *prompt)
80 {
81         char buf[1024];
82         snprintf(identity_file, sizeof(identity_file), "%s/%s",
83             pw->pw_dir,
84             dsa_mode ? SSH_CLIENT_ID_DSA: SSH_CLIENT_IDENTITY);
85         printf("%s (%s): ", prompt, identity_file);
86         fflush(stdout);
87         if (fgets(buf, sizeof(buf), stdin) == NULL)
88                 exit(1);
89         if (strchr(buf, '\n'))
90                 *strchr(buf, '\n') = 0;
91         if (strcmp(buf, "") != 0)
92                 strlcpy(identity_file, buf, sizeof(identity_file));
93         have_identity = 1;
94 }
95
96 int
97 try_load_key(char *filename, Key *k)
98 {
99         int success = 1;
100         if (!load_private_key(filename, "", k, NULL)) {
101                 char *pass = read_passphrase("Enter passphrase: ", 1);
102                 if (!load_private_key(filename, pass, k, NULL)) {
103                         success = 0;
104                 }
105                 memset(pass, 0, strlen(pass));
106                 xfree(pass);
107         }
108         return success;
109 }
110
111 #define SSH_COM_MAGIC_BEGIN "---- BEGIN SSH2 PUBLIC KEY ----"
112 #define SSH_COM_MAGIC_END   "---- END SSH2 PUBLIC KEY ----"
113
114 void
115 do_convert_to_ssh2(struct passwd *pw)
116 {
117         Key *k;
118         int len;
119         unsigned char *blob;
120         struct stat st;
121
122         if (!have_identity)
123                 ask_filename(pw, "Enter file in which the key is");
124         if (stat(identity_file, &st) < 0) {
125                 perror(identity_file);
126                 exit(1);
127         }
128         k = key_new(KEY_DSA);
129         if (!try_load_key(identity_file, k)) {
130                 fprintf(stderr, "load failed\n");
131                 exit(1);
132         }
133         dsa_make_key_blob(k, &blob, &len);
134         fprintf(stdout, "%s\n", SSH_COM_MAGIC_BEGIN);
135         fprintf(stdout,
136             "Comment: \"%d-bit DSA, converted from openssh by %s@%s\"\n",
137             BN_num_bits(k->dsa->p),
138             pw->pw_name, hostname);
139         dump_base64(stdout, blob, len);
140         fprintf(stdout, "%s\n", SSH_COM_MAGIC_END);
141         key_free(k);
142         xfree(blob);
143         exit(0);
144 }
145
146 void
147 do_convert_from_ssh2(struct passwd *pw)
148 {
149         Key *k;
150         int blen;
151         char line[1024], *p;
152         char blob[8096];
153         char encoded[8096];
154         struct stat st;
155         int escaped = 0;
156         FILE *fp;
157
158         if (!have_identity)
159                 ask_filename(pw, "Enter file in which the key is");
160         if (stat(identity_file, &st) < 0) {
161                 perror(identity_file);
162                 exit(1);
163         }
164         fp = fopen(identity_file, "r");
165         if (fp == NULL) {
166                 perror(identity_file);
167                 exit(1);
168         }
169         encoded[0] = '\0';
170         while (fgets(line, sizeof(line), fp)) {
171                 if (!(p = strchr(line, '\n'))) {
172                         fprintf(stderr, "input line too long.\n");
173                         exit(1);
174                 }
175                 if (p > line && p[-1] == '\\')
176                         escaped++;
177                 if (strncmp(line, "----", 4) == 0 ||
178                     strstr(line, ": ") != NULL) {
179                         fprintf(stderr, "ignore: %s", line);
180                         continue;
181                 }
182                 if (escaped) {
183                         escaped--;
184                         fprintf(stderr, "escaped: %s", line);
185                         continue;
186                 }
187                 *p = '\0';
188                 strlcat(encoded, line, sizeof(encoded));
189         }
190         blen = uudecode(encoded, (unsigned char *)blob, sizeof(blob));
191         if (blen < 0) {
192                 fprintf(stderr, "uudecode failed.\n");
193                 exit(1);
194         }
195         k = dsa_key_from_blob(blob, blen);
196         if (!key_write(k, stdout))
197                 fprintf(stderr, "key_write failed");
198         key_free(k);
199         fprintf(stdout, "\n");
200         fclose(fp);
201         exit(0);
202 }
203
204 void
205 do_print_public(struct passwd *pw)
206 {
207         Key *k;
208         int len;
209         unsigned char *blob;
210         struct stat st;
211
212         if (!have_identity)
213                 ask_filename(pw, "Enter file in which the key is");
214         if (stat(identity_file, &st) < 0) {
215                 perror(identity_file);
216                 exit(1);
217         }
218         k = key_new(KEY_DSA);
219         if (!try_load_key(identity_file, k)) {
220                 fprintf(stderr, "load failed\n");
221                 exit(1);
222         }
223         dsa_make_key_blob(k, &blob, &len);
224         if (!key_write(k, stdout))
225                 fprintf(stderr, "key_write failed");
226         key_free(k);
227         xfree(blob);
228         fprintf(stdout, "\n");
229         exit(0);
230 }
231
232 void
233 do_fingerprint(struct passwd *pw)
234 {
235         /* XXX RSA1 only */
236
237         FILE *f;
238         Key *public;
239         char *comment = NULL, *cp, *ep, line[16*1024];
240         int i, skip = 0, num = 1, invalid = 1;
241         unsigned int ignore;
242         struct stat st;
243
244         if (!have_identity)
245                 ask_filename(pw, "Enter file in which the key is");
246         if (stat(identity_file, &st) < 0) {
247                 perror(identity_file);
248                 exit(1);
249         }
250         public = key_new(KEY_RSA);
251         if (load_public_key(identity_file, public, &comment)) {
252                 printf("%d %s %s\n", BN_num_bits(public->rsa->n),
253                     key_fingerprint(public), comment);
254                 key_free(public);
255                 exit(0);
256         }
257
258         f = fopen(identity_file, "r");
259         if (f != NULL) {
260                 while (fgets(line, sizeof(line), f)) {
261                         i = strlen(line) - 1;
262                         if (line[i] != '\n') {
263                                 error("line %d too long: %.40s...", num, line);
264                                 skip = 1;
265                                 continue;
266                         }
267                         num++;
268                         if (skip) {
269                                 skip = 0;
270                                 continue;
271                         }
272                         line[i] = '\0';
273
274                         /* Skip leading whitespace, empty and comment lines. */
275                         for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
276                                 ;
277                         if (!*cp || *cp == '\n' || *cp == '#')
278                                 continue ;
279                         i = strtol(cp, &ep, 10);
280                         if (i == 0 || ep == NULL || (*ep != ' ' && *ep != '\t')) {
281                                 int quoted = 0;
282                                 comment = cp;
283                                 for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
284                                         if (*cp == '\\' && cp[1] == '"')
285                                                 cp++;   /* Skip both */
286                                         else if (*cp == '"')
287                                                 quoted = !quoted;
288                                 }
289                                 if (!*cp)
290                                         continue;
291                                 *cp++ = '\0';
292                         }
293                         ep = cp;
294                         if (auth_rsa_read_key(&cp, &ignore, public->rsa->e, public->rsa->n)) {
295                                 invalid = 0;
296                                 comment = *cp ? cp : comment;
297                                 printf("%d %s %s\n", key_size(public),
298                                     key_fingerprint(public),
299                                     comment ? comment : "no comment");
300                         }
301                 }
302                 fclose(f);
303         }
304         key_free(public);
305         if (invalid) {
306                 printf("%s is not a valid key file.\n", identity_file);
307                 exit(1);
308         }
309         exit(0);
310 }
311
312 /*
313  * Perform changing a passphrase.  The argument is the passwd structure
314  * for the current user.
315  */
316 void
317 do_change_passphrase(struct passwd *pw)
318 {
319         char *comment;
320         char *old_passphrase, *passphrase1, *passphrase2;
321         struct stat st;
322         Key *private;
323         Key *public;
324         int type = dsa_mode ? KEY_DSA : KEY_RSA;
325
326         if (!have_identity)
327                 ask_filename(pw, "Enter file in which the key is");
328         if (stat(identity_file, &st) < 0) {
329                 perror(identity_file);
330                 exit(1);
331         }
332
333         if (type == KEY_RSA) {
334                 /* XXX this works currently only for RSA */
335                 public = key_new(type);
336                 if (!load_public_key(identity_file, public, NULL)) {
337                         printf("%s is not a valid key file.\n", identity_file);
338                         exit(1);
339                 }
340                 /* Clear the public key since we are just about to load the whole file. */
341                 key_free(public);
342         }
343
344         /* Try to load the file with empty passphrase. */
345         private = key_new(type);
346         if (!load_private_key(identity_file, "", private, &comment)) {
347                 if (identity_passphrase)
348                         old_passphrase = xstrdup(identity_passphrase);
349                 else
350                         old_passphrase = read_passphrase("Enter old passphrase: ", 1);
351                 if (!load_private_key(identity_file, old_passphrase, private, &comment)) {
352                         memset(old_passphrase, 0, strlen(old_passphrase));
353                         xfree(old_passphrase);
354                         printf("Bad passphrase.\n");
355                         exit(1);
356                 }
357                 memset(old_passphrase, 0, strlen(old_passphrase));
358                 xfree(old_passphrase);
359         }
360         printf("Key has comment '%s'\n", comment);
361
362         /* Ask the new passphrase (twice). */
363         if (identity_new_passphrase) {
364                 passphrase1 = xstrdup(identity_new_passphrase);
365                 passphrase2 = NULL;
366         } else {
367                 passphrase1 =
368                         read_passphrase("Enter new passphrase (empty for no passphrase): ", 1);
369                 passphrase2 = read_passphrase("Enter same passphrase again: ", 1);
370
371                 /* Verify that they are the same. */
372                 if (strcmp(passphrase1, passphrase2) != 0) {
373                         memset(passphrase1, 0, strlen(passphrase1));
374                         memset(passphrase2, 0, strlen(passphrase2));
375                         xfree(passphrase1);
376                         xfree(passphrase2);
377                         printf("Pass phrases do not match.  Try again.\n");
378                         exit(1);
379                 }
380                 /* Destroy the other copy. */
381                 memset(passphrase2, 0, strlen(passphrase2));
382                 xfree(passphrase2);
383         }
384
385         /* Save the file using the new passphrase. */
386         if (!save_private_key(identity_file, passphrase1, private, comment)) {
387                 printf("Saving the key failed: %s: %s.\n",
388                        identity_file, strerror(errno));
389                 memset(passphrase1, 0, strlen(passphrase1));
390                 xfree(passphrase1);
391                 key_free(private);
392                 xfree(comment);
393                 exit(1);
394         }
395         /* Destroy the passphrase and the copy of the key in memory. */
396         memset(passphrase1, 0, strlen(passphrase1));
397         xfree(passphrase1);
398         key_free(private);               /* Destroys contents */
399         xfree(comment);
400
401         printf("Your identification has been saved with the new passphrase.\n");
402         exit(0);
403 }
404
405 /*
406  * Change the comment of a private key file.
407  */
408 void
409 do_change_comment(struct passwd *pw)
410 {
411         char new_comment[1024], *comment;
412         Key *private;
413         Key *public;
414         char *passphrase;
415         struct stat st;
416         FILE *f;
417
418         if (!have_identity)
419                 ask_filename(pw, "Enter file in which the key is");
420         if (stat(identity_file, &st) < 0) {
421                 perror(identity_file);
422                 exit(1);
423         }
424         /*
425          * Try to load the public key from the file the verify that it is
426          * readable and of the proper format.
427          */
428         public = key_new(KEY_RSA);
429         if (!load_public_key(identity_file, public, NULL)) {
430                 printf("%s is not a valid key file.\n", identity_file);
431                 exit(1);
432         }
433
434         private = key_new(KEY_RSA);
435         if (load_private_key(identity_file, "", private, &comment))
436                 passphrase = xstrdup("");
437         else {
438                 if (identity_passphrase)
439                         passphrase = xstrdup(identity_passphrase);
440                 else if (identity_new_passphrase)
441                         passphrase = xstrdup(identity_new_passphrase);
442                 else
443                         passphrase = read_passphrase("Enter passphrase: ", 1);
444                 /* Try to load using the passphrase. */
445                 if (!load_private_key(identity_file, passphrase, private, &comment)) {
446                         memset(passphrase, 0, strlen(passphrase));
447                         xfree(passphrase);
448                         printf("Bad passphrase.\n");
449                         exit(1);
450                 }
451         }
452         printf("Key now has comment '%s'\n", comment);
453
454         if (identity_comment) {
455                 strlcpy(new_comment, identity_comment, sizeof(new_comment));
456         } else {
457                 printf("Enter new comment: ");
458                 fflush(stdout);
459                 if (!fgets(new_comment, sizeof(new_comment), stdin)) {
460                         memset(passphrase, 0, strlen(passphrase));
461                         key_free(private);
462                         exit(1);
463                 }
464                 if (strchr(new_comment, '\n'))
465                         *strchr(new_comment, '\n') = 0;
466         }
467
468         /* Save the file using the new passphrase. */
469         if (!save_private_key(identity_file, passphrase, private, new_comment)) {
470                 printf("Saving the key failed: %s: %s.\n",
471                        identity_file, strerror(errno));
472                 memset(passphrase, 0, strlen(passphrase));
473                 xfree(passphrase);
474                 key_free(private);
475                 xfree(comment);
476                 exit(1);
477         }
478         memset(passphrase, 0, strlen(passphrase));
479         xfree(passphrase);
480         key_free(private);
481
482         strlcat(identity_file, ".pub", sizeof(identity_file));
483         f = fopen(identity_file, "w");
484         if (!f) {
485                 printf("Could not save your public key in %s\n", identity_file);
486                 exit(1);
487         }
488         if (!key_write(public, f))
489                 fprintf(stderr, "write key failed");
490         key_free(public);
491         fprintf(f, " %s\n", new_comment);
492         fclose(f);
493
494         xfree(comment);
495
496         printf("The comment in your key file has been changed.\n");
497         exit(0);
498 }
499
500 void
501 usage(void)
502 {
503         printf("Usage: %s [-lpqxXydc] [-b bits] [-f file] [-C comment] [-N new-pass] [-P pass]\n", __progname);
504         exit(1);
505 }
506
507 /*
508  * Main program for key management.
509  */
510 int
511 main(int ac, char **av)
512 {
513         char dotsshdir[16 * 1024], comment[1024], *passphrase1, *passphrase2;
514         struct passwd *pw;
515         int opt;
516         struct stat st;
517         FILE *f;
518         Key *private;
519         Key *public;
520         extern int optind;
521         extern char *optarg;
522
523         init_rng();
524
525         SSLeay_add_all_algorithms();
526
527         /* we need this for the home * directory.  */
528         pw = getpwuid(getuid());
529         if (!pw) {
530                 printf("You don't exist, go away!\n");
531                 exit(1);
532         }
533         if (gethostname(hostname, sizeof(hostname)) < 0) {
534                 perror("gethostname");
535                 exit(1);
536         }
537
538         while ((opt = getopt(ac, av, "dqpclRxXyb:f:P:N:C:")) != EOF) {
539                 switch (opt) {
540                 case 'b':
541                         bits = atoi(optarg);
542                         if (bits < 512 || bits > 32768) {
543                                 printf("Bits has bad value.\n");
544                                 exit(1);
545                         }
546                         break;
547
548                 case 'l':
549                         print_fingerprint = 1;
550                         break;
551
552                 case 'p':
553                         change_passphrase = 1;
554                         break;
555
556                 case 'c':
557                         change_comment = 1;
558                         break;
559
560                 case 'f':
561                         strlcpy(identity_file, optarg, sizeof(identity_file));
562                         have_identity = 1;
563                         break;
564
565                 case 'P':
566                         identity_passphrase = optarg;
567                         break;
568
569                 case 'N':
570                         identity_new_passphrase = optarg;
571                         break;
572
573                 case 'C':
574                         identity_comment = optarg;
575                         break;
576
577                 case 'q':
578                         quiet = 1;
579                         break;
580
581                 case 'R':
582                         if (rsa_alive() == 0)
583                                 exit(1);
584                         else
585                                 exit(0);
586                         break;
587
588                 case 'x':
589                         convert_to_ssh2 = 1;
590                         break;
591
592                 case 'X':
593                         convert_from_ssh2 = 1;
594                         break;
595
596                 case 'y':
597                         print_public = 1;
598                         break;
599
600                 case 'd':
601                         dsa_mode = 1;
602                         break;
603
604                 case '?':
605                 default:
606                         usage();
607                 }
608         }
609         if (optind < ac) {
610                 printf("Too many arguments.\n");
611                 usage();
612         }
613         if (change_passphrase && change_comment) {
614                 printf("Can only have one of -p and -c.\n");
615                 usage();
616         }
617         /* check if RSA support is needed and exists */
618         if (dsa_mode == 0 && rsa_alive() == 0) {
619                 fprintf(stderr,
620                         "%s: no RSA support in libssl and libcrypto.  See ssl(8).\n",
621                         __progname);
622                 exit(1);
623         }
624         if (print_fingerprint)
625                 do_fingerprint(pw);
626         if (change_passphrase)
627                 do_change_passphrase(pw);
628         if (change_comment)
629                 do_change_comment(pw);
630         if (convert_to_ssh2)
631                 do_convert_to_ssh2(pw);
632         if (convert_from_ssh2)
633                 do_convert_from_ssh2(pw);
634         if (print_public)
635                 do_print_public(pw);
636
637         arc4random_stir();
638
639         if (dsa_mode != 0) {
640                 if (!quiet)
641                         printf("Generating DSA parameter and key.\n");
642                 public = private = dsa_generate_key(bits);
643                 if (private == NULL) {
644                         fprintf(stderr, "dsa_generate_keys failed");
645                         exit(1);
646                 }
647         } else {
648                 if (quiet)
649                         rsa_set_verbose(0);
650                 /* Generate the rsa key pair. */
651                 public = key_new(KEY_RSA);
652                 private = key_new(KEY_RSA);
653                 rsa_generate_key(private->rsa, public->rsa, bits);
654         }
655
656         if (!have_identity)
657                 ask_filename(pw, "Enter file in which to save the key");
658
659         /* Create ~/.ssh directory if it doesn\'t already exist. */
660         snprintf(dotsshdir, sizeof dotsshdir, "%s/%s", pw->pw_dir, SSH_USER_DIR);
661         if (strstr(identity_file, dotsshdir) != NULL &&
662             stat(dotsshdir, &st) < 0) {
663                 if (mkdir(dotsshdir, 0700) < 0)
664                         error("Could not create directory '%s'.", dotsshdir);
665                 else if (!quiet)
666                         printf("Created directory '%s'.\n", dotsshdir);
667         }
668         /* If the file already exists, ask the user to confirm. */
669         if (stat(identity_file, &st) >= 0) {
670                 char yesno[3];
671                 printf("%s already exists.\n", identity_file);
672                 printf("Overwrite (y/n)? ");
673                 fflush(stdout);
674                 if (fgets(yesno, sizeof(yesno), stdin) == NULL)
675                         exit(1);
676                 if (yesno[0] != 'y' && yesno[0] != 'Y')
677                         exit(1);
678         }
679         /* Ask for a passphrase (twice). */
680         if (identity_passphrase)
681                 passphrase1 = xstrdup(identity_passphrase);
682         else if (identity_new_passphrase)
683                 passphrase1 = xstrdup(identity_new_passphrase);
684         else {
685 passphrase_again:
686                 passphrase1 =
687                         read_passphrase("Enter passphrase (empty for no passphrase): ", 1);
688                 passphrase2 = read_passphrase("Enter same passphrase again: ", 1);
689                 if (strcmp(passphrase1, passphrase2) != 0) {
690                         /* The passphrases do not match.  Clear them and retry. */
691                         memset(passphrase1, 0, strlen(passphrase1));
692                         memset(passphrase2, 0, strlen(passphrase2));
693                         xfree(passphrase1);
694                         xfree(passphrase2);
695                         printf("Passphrases do not match.  Try again.\n");
696                         goto passphrase_again;
697                 }
698                 /* Clear the other copy of the passphrase. */
699                 memset(passphrase2, 0, strlen(passphrase2));
700                 xfree(passphrase2);
701         }
702
703         if (identity_comment) {
704                 strlcpy(comment, identity_comment, sizeof(comment));
705         } else {
706                 /* Create default commend field for the passphrase. */
707                 snprintf(comment, sizeof comment, "%s@%s", pw->pw_name, hostname);
708         }
709
710         /* Save the key with the given passphrase and comment. */
711         if (!save_private_key(identity_file, passphrase1, private, comment)) {
712                 printf("Saving the key failed: %s: %s.\n",
713                     identity_file, strerror(errno));
714                 memset(passphrase1, 0, strlen(passphrase1));
715                 xfree(passphrase1);
716                 exit(1);
717         }
718         /* Clear the passphrase. */
719         memset(passphrase1, 0, strlen(passphrase1));
720         xfree(passphrase1);
721
722         /* Clear the private key and the random number generator. */
723         if (private != public) {
724                 key_free(private);
725         }
726         arc4random_stir();
727
728         if (!quiet)
729                 printf("Your identification has been saved in %s.\n", identity_file);
730
731         strlcat(identity_file, ".pub", sizeof(identity_file));
732         f = fopen(identity_file, "w");
733         if (!f) {
734                 printf("Could not save your public key in %s\n", identity_file);
735                 exit(1);
736         }
737         if (!key_write(public, f))
738                 fprintf(stderr, "write key failed");
739         fprintf(f, " %s\n", comment);
740         fclose(f);
741
742         if (!quiet) {
743                 printf("Your public key has been saved in %s.\n",
744                     identity_file);
745                 printf("The key fingerprint is:\n");
746                 printf("%s %s\n", key_fingerprint(public), comment);
747         }
748
749         key_free(public);
750         exit(0);
751 }
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