ucert.c

   1 /*
   2  * Copyright (C) 2018 Daniel Golle <daniel@makrotopia.org>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 3
   6  * as published by the Free Software Foundation
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  */
  13
  14 #define _GNU_SOURCE
  15
  16 #include <fcntl.h>
  17 #include <dlfcn.h>
  18 #include <stdio.h>
  19 #include <stdbool.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <getopt.h>
  23 #include <stdint.h>
  24 #include <unistd.h>
  25 #include <inttypes.h>
  26 #include <sys/stat.h>
  27 #include <sys/wait.h>
  28
  29 #include <json-c/json.h>
  30 #include <libubox/blob.h>
  31 #include <libubox/utils.h>
  32 #include <libubox/list.h>
  33 #include <libubox/vlist.h>
  34 #include <libubox/blobmsg_json.h>
  35
  36 #include "usign.h"
  37
  38 #define CERT_BUF_LEN 4096
  39
  40 static enum {
  41         CMD_APPEND,
  42         CMD_DUMP,
  43         CMD_ISSUE,
  44         CMD_REVOKE,
  45         CMD_VERIFY,
  46         CMD_NONE,
  47 } cmd = CMD_NONE;
  48
  49 static bool quiet;
  50
  51 /*
  52  * ucert structure
  53  * |               BLOB                    |
  54  * |    SIGNATURE    |       PAYLOAD       |
  55  * |                 |[ BLOBMSG CONTAINER ]|
  56  * |                 |[[T,i,v,e,f,pubkey ]]|
  57  */
  58 enum cert_attr {
  59         CERT_ATTR_SIGNATURE,
  60         CERT_ATTR_PAYLOAD,
  61         CERT_ATTR_MAX
  62 };
  63
  64 static const struct blob_attr_info cert_policy[CERT_ATTR_MAX] = {
  65         [CERT_ATTR_SIGNATURE] = { .type = BLOB_ATTR_BINARY },
  66         [CERT_ATTR_PAYLOAD] = { .type = BLOB_ATTR_NESTED },
  67 };
  68
  69 enum cert_cont_attr {
  70         CERT_CT_ATTR_PAYLOAD,
  71         CERT_CT_ATTR_MAX
  72 };
  73
  74 static const struct blobmsg_policy cert_cont_policy[CERT_CT_ATTR_MAX] = {
  75         [CERT_CT_ATTR_PAYLOAD] = { .name = "ucert", .type = BLOBMSG_TYPE_TABLE },
  76 };
  77
  78 enum cert_payload_attr {
  79         CERT_PL_ATTR_CERTTYPE,
  80         CERT_PL_ATTR_CERTID,
  81         CERT_PL_ATTR_VALIDFROMTIME,
  82         CERT_PL_ATTR_EXPIRETIME,
  83         CERT_PL_ATTR_PUBKEY,
  84         CERT_PL_ATTR_KEY_FINGERPRINT,
  85         CERT_PL_ATTR_MAX
  86 };
  87
  88 enum certtype_id {
  89         CERTTYPE_UNSPEC,
  90         CERTTYPE_AUTH,
  91         CERTTYPE_REVOKE
  92 };
  93
  94 static const struct blobmsg_policy cert_payload_policy[CERT_PL_ATTR_MAX] = {
  95         [CERT_PL_ATTR_CERTTYPE] = { .name = "certtype", .type = BLOBMSG_TYPE_INT32 },
  96         [CERT_PL_ATTR_CERTID] = { .name = "certid", .type = BLOBMSG_TYPE_INT32 },
  97         [CERT_PL_ATTR_VALIDFROMTIME] = { .name = "validfrom", .type = BLOBMSG_TYPE_INT64 },
  98         [CERT_PL_ATTR_EXPIRETIME] = { .name = "expiresat", .type = BLOBMSG_TYPE_INT64 },
  99         [CERT_PL_ATTR_PUBKEY] = { .name = "pubkey", .type = BLOBMSG_TYPE_STRING },
 100         [CERT_PL_ATTR_KEY_FINGERPRINT] = { .name = "fingerprint", .type = BLOBMSG_TYPE_STRING },
 101 };
 102
 103 /* list to store certificate chain at runtime */
 104 struct cert_object {
 105         struct list_head list;
 106         struct blob_attr *cert[CERT_ATTR_MAX];
 107 };
 108
 109 /* write buffer to file */
 110 static int write_file(const char *filename, void *buf, size_t len, bool append) {
 111         FILE *f;
 112         size_t outlen;
 113
 114         f = fopen(filename, append?"a":"w");
 115         if (!f)
 116                 return 1;
 117
 118         outlen = fwrite(buf, 1, len, f);
 119         fclose(f);
 120         return (outlen == len);
 121 }
 122
 123 /* load certfile into list */
 124 static int cert_load(const char *certfile, struct list_head *chain) {
 125         FILE *f;
 126         struct blob_attr *certtb[CERT_ATTR_MAX];
 127         struct blob_attr *bufpt;
 128         struct cert_object *cobj;
 129         char filebuf[CERT_BUF_LEN];
 130         int ret = 0, pret = 0;
 131         int len, pos = 0;
 132
 133         f = fopen(certfile, "r");
 134         if (!f)
 135                 return 1;
 136
 137         len = fread(&filebuf, 1, CERT_BUF_LEN - 1, f);
 138         if (len < 64)
 139                 return 1;
 140
 141         ret = ferror(f) || !feof(f);
 142         fclose(f);
 143         if (ret)
 144                 return 1;
 145
 146         bufpt = (struct blob_attr *)filebuf;
 147         do {
 148                 pret = blob_parse(bufpt, certtb, cert_policy, CERT_ATTR_MAX);
 149                 if (pret <= 0)
 150                         /* no attributes found */
 151                         break;
 152
 153                 if (pos + blob_pad_len(bufpt) > len)
 154                         /* blob exceeds filebuffer */
 155                         break;
 156                 else
 157                         pos += blob_pad_len(bufpt);
 158
 159                 cobj = calloc(1, sizeof(*cobj));
 160                 memcpy(cobj->cert, &certtb, sizeof(certtb));
 161                 list_add_tail(&cobj->list, chain);
 162                 ret += pret;
 163                 bufpt = blob_next(bufpt);
 164         /* repeat parsing while there is still enough remaining data in buffer */
 165         } while(len > pos + sizeof(struct blob_attr));
 166
 167         return (ret <= 0);
 168 }
 169
 170 /* append signature to certfile */
 171 static int cert_append(const char *certfile, const char *sigfile) {
 172         FILE *fs;
 173         char filebuf[CERT_BUF_LEN];
 174         struct blob_buf sigbuf;
 175         int len;
 176         int ret;
 177
 178         fs = fopen(sigfile, "r");
 179         if (!fs)
 180                 return 1;
 181
 182         len = fread(&filebuf, 1, CERT_BUF_LEN - 1, fs);
 183         ret = ferror(fs) || !feof(fs) || (len < 64);
 184         fclose(fs);
 185         if (ret)
 186                 return 1;
 187
 188         blob_buf_init(&sigbuf, 0);
 189         blob_put(&sigbuf, CERT_ATTR_SIGNATURE, filebuf, len);
 190         ret = write_file(certfile, sigbuf.head, blob_raw_len(sigbuf.head), true);
 191         blob_buf_free(&sigbuf);
 192         return ret;
 193 }
 194
 195 /* verify the signature of a single chain element */
 196 static int cert_verify_blob(struct blob_attr *cert[CERT_ATTR_MAX],
 197                        const char *pubkeyfile, const char *pubkeydir) {
 198         int i;
 199         char msgfname[256], sigfname[256];
 200         int ret;
 201         char tmpdir[] = "/tmp/ucert-XXXXXX";
 202
 203         if (mkdtemp(tmpdir) == NULL)
 204                 return errno;
 205
 206         snprintf(msgfname, sizeof(msgfname) - 1, "%s/%s", tmpdir, "payload");
 207         snprintf(sigfname, sizeof(sigfname) - 1, "%s/%s", tmpdir, "payload.sig");
 208
 209         for (i = 0; i < CERT_ATTR_MAX; i++) {
 210                 struct blob_attr *v = cert[i];
 211
 212                 if (!v)
 213                         break;
 214
 215                 switch(cert_policy[i].type) {
 216                 case BLOB_ATTR_BINARY:
 217                         write_file(sigfname, blob_data(v), blob_len(v), false);
 218                         break;
 219                 case BLOB_ATTR_NESTED:
 220                         write_file(msgfname, blob_data(v), blob_len(v), false);
 221                         break;
 222                 }
 223         }
 224
 225         ret = usign_v(msgfname, pubkeyfile, pubkeydir, sigfname, quiet);
 226
 227         unlink(msgfname);
 228         unlink(sigfname);
 229         rmdir(tmpdir);
 230
 231         return ret;
 232 }
 233
 234 /* verify cert chain (and message) */
 235 static int chain_verify(const char *msgfile, const char *pubkeyfile,
 236                         const char *pubkeydir, struct list_head *chain) {
 237         struct cert_object *cobj;
 238         struct blob_attr *containertb[CERT_CT_ATTR_MAX];
 239         struct blob_attr *payloadtb[CERT_PL_ATTR_MAX];
 240         char tmpdir[] = "/tmp/ucert-XXXXXX";
 241         char chainedpubkey[256] = {0};
 242         char chainedfp[17] = {0};
 243         char extsigfile[256] = {0};
 244         int ret = 1;
 245         int checkmsg = 0;
 246
 247         if (mkdtemp(tmpdir) == NULL)
 248                 return errno;
 249
 250         if (msgfile)
 251                 checkmsg = -1;
 252
 253         list_for_each_entry(cobj, chain, list) {
 254                 /* blob has payload, verify that using signature */
 255                 if (cobj->cert[CERT_ATTR_PAYLOAD]) {
 256                         struct timeval tv;
 257                         uint64_t validfrom;
 258                         uint64_t expiresat;
 259                         uint32_t certtype;
 260
 261                         ret = cert_verify_blob(cobj->cert, chainedpubkey[0]?chainedpubkey:pubkeyfile, pubkeydir);
 262                         if (ret)
 263                                 goto clean_and_return;
 264
 265                         blobmsg_parse(cert_cont_policy,
 266                                       ARRAY_SIZE(cert_cont_policy),
 267                                       containertb,
 268                                       blob_data(cobj->cert[CERT_ATTR_PAYLOAD]),
 269                                       blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
 270                         if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
 271                                 ret = 1;
 272                                 fprintf(stderr, "no ucert in signed payload\n");
 273                                 goto clean_and_return;
 274                         }
 275                         blobmsg_parse(cert_payload_policy,
 276                                       ARRAY_SIZE(cert_payload_policy),
 277                                       payloadtb,
 278                                       blobmsg_data(containertb[CERT_CT_ATTR_PAYLOAD]),
 279                                       blobmsg_data_len(containertb[CERT_CT_ATTR_PAYLOAD]));
 280
 281                         if (!payloadtb[CERT_PL_ATTR_CERTTYPE] ||
 282                             !payloadtb[CERT_PL_ATTR_VALIDFROMTIME] ||
 283                             !payloadtb[CERT_PL_ATTR_EXPIRETIME] ||
 284                             !payloadtb[CERT_PL_ATTR_PUBKEY]) {
 285                                 ret = 1;
 286                                 fprintf(stderr, "missing mandatory ucert attributes\n");
 287                                 goto clean_and_return;
 288                         }
 289                         certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
 290                         validfrom = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_VALIDFROMTIME]);
 291                         expiresat = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_EXPIRETIME]);
 292
 293                         if (certtype != CERTTYPE_AUTH) {
 294                                 ret = 2;
 295                                 fprintf(stderr, "wrong certificate type\n");
 296                                 goto clean_and_return;
 297                         }
 298
 299                         gettimeofday(&tv, NULL);
 300                         if (tv.tv_sec < validfrom ||
 301                             tv.tv_sec >= expiresat) {
 302                                 ret = 3;
 303                                 fprintf(stderr, "certificate expired\n");
 304                                 goto clean_and_return;
 305                         }
 306
 307                         snprintf(chainedpubkey, sizeof(chainedpubkey) - 1, "%s/%s", tmpdir, "chained-pubkey");
 308                         write_file(chainedpubkey,
 309                                    blobmsg_data(payloadtb[CERT_PL_ATTR_PUBKEY]),
 310                                    blobmsg_data_len(payloadtb[CERT_PL_ATTR_PUBKEY]),
 311                                    false);
 312
 313                         if (usign_f_pubkey(chainedfp, chainedpubkey)) {
 314                                 if (!quiet)
 315                                         fprintf(stderr, "cannot get fingerprint for chained key\n");
 316                                 ret = 2;
 317                                 goto clean_and_return;
 318                         }
 319                         if (pubkeydir && _usign_key_is_revoked(chainedfp, pubkeydir)) {
 320                                 if (!quiet)
 321                                         fprintf(stderr, "key %s has been revoked!\n", chainedfp);
 322                                 ret = 4;
 323                                 goto clean_and_return;
 324                         }
 325                 } else {
 326                 /* blob doesn't have payload, verify message using signature */
 327                         if (msgfile) {
 328                                 snprintf(extsigfile, sizeof(extsigfile) - 1, "%s/%s", tmpdir, "ext-sig");
 329                                 write_file(extsigfile,
 330                                            blob_data(cobj->cert[CERT_ATTR_SIGNATURE]),
 331                                            blob_len(cobj->cert[CERT_ATTR_SIGNATURE]),
 332                                            false);
 333                                 checkmsg = ret = usign_v(msgfile,
 334                                               chainedpubkey[0]?chainedpubkey:pubkeyfile,
 335                                               pubkeydir, extsigfile, quiet);
 336                                 unlink(extsigfile);
 337                         } else {
 338                                 fprintf(stderr, "stray trailing signature without anything to verify!\n");
 339                                 ret = 1;
 340                         };
 341                 }
 342         }
 343
 344         if (checkmsg == -1)
 345                 fprintf(stderr, "missing signature to verify message!\n");
 346
 347 clean_and_return:
 348         if (chainedpubkey[0])
 349                 unlink(chainedpubkey);
 350         rmdir(tmpdir);
 351         return ret | checkmsg;
 352 }
 353
 354 /* dump single chain element to console */
 355 static void cert_dump_blob(struct blob_attr *cert[CERT_ATTR_MAX]) {
 356         int i;
 357
 358         for (i = 0; i < CERT_ATTR_MAX; i++) {
 359                 struct blob_attr *v = cert[i];
 360
 361                 if (!v)
 362                         continue;
 363
 364                 switch(cert_policy[i].type) {
 365                 case BLOB_ATTR_BINARY:
 366                         fprintf(stdout, "signature:\n---\n%s---\n", (char *) blob_data(v));
 367                         break;
 368                 case BLOB_ATTR_NESTED:
 369                         fprintf(stdout, "payload:\n---\n%s\n---\n", blobmsg_format_json_indent(blob_data(v), false, 0));
 370                         break;
 371                 }
 372         }
 373 }
 374
 375 /* dump certfile to console */
 376 static int cert_dump(const char *certfile) {
 377         struct cert_object *cobj;
 378         static LIST_HEAD(certchain);
 379         unsigned int count = 0;
 380
 381         if (cert_load(certfile, &certchain)) {
 382                 fprintf(stderr, "cannot parse cert\n");
 383                 return 1;
 384         }
 385
 386         list_for_each_entry(cobj, &certchain, list) {
 387                 fprintf(stderr, "=== CHAIN ELEMENT %02u ===\n", ++count);
 388                 cert_dump_blob(cobj->cert);
 389                 fprintf(stderr, "========================\n");
 390         }
 391
 392         return 0;
 393 }
 394
 395 /* issue an auth certificate for pubkey */
 396 static int cert_issue(const char *certfile, const char *pubkeyfile, const char *seckeyfile) {
 397         struct blob_buf certbuf;
 398         struct blob_buf payloadbuf;
 399         struct timeval tv;
 400         struct stat st;
 401         int pklen, siglen;
 402         int revoker = 1;
 403         void *c;
 404         FILE *pkf, *sigf;
 405         char pkb[512];
 406         char sigb[512];
 407         char fname[256], sfname[256];
 408         char pkfp[17];
 409         char tmpdir[] = "/tmp/ucert-XXXXXX";
 410
 411         if (stat(certfile, &st) == 0) {
 412                 fprintf(stderr, "certfile %s exists, won't overwrite.\n", certfile);
 413                 return -1;
 414         }
 415
 416         pkf = fopen(pubkeyfile, "r");
 417         if (!pkf)
 418                 return -1;
 419
 420         pklen = fread(pkb, 1, 512, pkf);
 421         pkb[pklen] = '\0';
 422
 423         if (pklen < 32)
 424                 return -1;
 425
 426         fclose(pkf);
 427
 428         if (usign_f_pubkey(pkfp, pubkeyfile))
 429                 return -1;
 430
 431         gettimeofday(&tv, NULL);
 432
 433         if (mkdtemp(tmpdir) == NULL)
 434                 return errno;
 435
 436         while (revoker >= 0) {
 437                 blob_buf_init(&payloadbuf, 0);
 438                 c = blobmsg_open_table(&payloadbuf, "ucert");
 439                 blobmsg_add_u32(&payloadbuf, "certtype", revoker?CERTTYPE_REVOKE:CERTTYPE_AUTH);
 440                 blobmsg_add_u64(&payloadbuf, "validfrom", tv.tv_sec);
 441                 if (!revoker) {
 442                         blobmsg_add_u64(&payloadbuf, "expiresat", tv.tv_sec + 60 * 60 * 24 * 365);
 443                         blobmsg_add_string(&payloadbuf, "pubkey", pkb);
 444                 } else {
 445                         blobmsg_add_string(&payloadbuf, "fingerprint", pkfp);
 446                 }
 447
 448                 blobmsg_close_table(&payloadbuf, c);
 449
 450                 snprintf(fname, sizeof(fname) - 1, "%s/%s", tmpdir, revoker?"revoker":"payload");
 451                 write_file(fname, blob_data(payloadbuf.head), blob_len(payloadbuf.head), false);
 452
 453                 snprintf(sfname, sizeof(sfname) - 1, "%s/%s", tmpdir, revoker?"revoker.sig":"payload.sig");
 454                 if (usign_s(fname, seckeyfile, sfname, quiet))
 455                         return 1;
 456
 457                 sigf = fopen(sfname, "r");
 458                 if (!sigf)
 459                         return 1;
 460
 461                 siglen = fread(sigb, 1, 1024, sigf);
 462                 if (siglen < 1)
 463                         return 1;
 464
 465                 sigb[siglen] = '\0';
 466                 fclose(sigf);
 467
 468                 unlink(fname);
 469                 unlink(sfname);
 470
 471                 blob_buf_init(&certbuf, 0);
 472                 blob_put(&certbuf, CERT_ATTR_SIGNATURE, sigb, siglen);
 473                 blob_put(&certbuf, CERT_ATTR_PAYLOAD, blob_data(payloadbuf.head), blob_len(payloadbuf.head));
 474                 snprintf(fname, sizeof(fname) - 1, "%s%s", certfile, revoker?".revoke":"");
 475                 write_file(fname, certbuf.head, blob_raw_len(certbuf.head), false);
 476                 blob_buf_free(&certbuf);
 477                 blob_buf_free(&payloadbuf);
 478
 479                 revoker--;
 480         }
 481
 482         rmdir(tmpdir);
 483
 484         return 0;
 485 }
 486
 487 /* process revoker certificate */
 488 static int cert_process_revoker(const char *certfile, const char *pubkeydir) {
 489         static LIST_HEAD(certchain);
 490         struct cert_object *cobj;
 491         struct blob_attr *containertb[CERT_CT_ATTR_MAX];
 492         struct blob_attr *payloadtb[CERT_PL_ATTR_MAX];
 493         struct stat st;
 494         struct timeval tv;
 495         uint64_t validfrom;
 496         uint32_t certtype;
 497         char *fingerprint;
 498         char rfname[512];
 499
 500         int ret;
 501
 502         if (cert_load(certfile, &certchain)) {
 503                 fprintf(stderr, "cannot parse cert\n");
 504                 return 1;
 505         }
 506
 507         list_for_each_entry(cobj, &certchain, list) {
 508                 /* blob has payload, verify that using signature */
 509                 if (!cobj->cert[CERT_ATTR_PAYLOAD])
 510                         return 2;
 511                 ret = cert_verify_blob(cobj->cert, NULL, pubkeydir);
 512                 if (ret)
 513                         return ret;
 514
 515                 blobmsg_parse(cert_cont_policy,
 516                               ARRAY_SIZE(cert_cont_policy),
 517                               containertb,
 518                               blob_data(cobj->cert[CERT_ATTR_PAYLOAD]),
 519                               blob_len(cobj->cert[CERT_ATTR_PAYLOAD]));
 520                 if (!containertb[CERT_CT_ATTR_PAYLOAD]) {
 521                         fprintf(stderr, "no ucert in signed payload\n");
 522                         return 2;
 523                 }
 524
 525                 blobmsg_parse(cert_payload_policy,
 526                               ARRAY_SIZE(cert_payload_policy),
 527                               payloadtb,
 528                               blobmsg_data(containertb[CERT_CT_ATTR_PAYLOAD]),
 529                               blobmsg_data_len(containertb[CERT_CT_ATTR_PAYLOAD]));
 530
 531                 if (!payloadtb[CERT_PL_ATTR_CERTTYPE] ||
 532                     !payloadtb[CERT_PL_ATTR_VALIDFROMTIME] ||
 533                     !payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]) {
 534                         fprintf(stderr, "missing mandatory ucert attributes\n");
 535                         return 2;
 536                 }
 537
 538                 certtype = blobmsg_get_u32(payloadtb[CERT_PL_ATTR_CERTTYPE]);
 539                 validfrom = blobmsg_get_u64(payloadtb[CERT_PL_ATTR_VALIDFROMTIME]);
 540                 fingerprint = blobmsg_get_string(payloadtb[CERT_PL_ATTR_KEY_FINGERPRINT]);
 541
 542                 if (certtype != CERTTYPE_REVOKE) {
 543                         fprintf(stderr, "wrong certificate type\n");
 544                         return 2;
 545                 }
 546
 547                 gettimeofday(&tv, NULL);
 548                 if (tv.tv_sec < validfrom) {
 549                         return 3;
 550                 }
 551
 552                 snprintf(rfname, sizeof(rfname)-1, "%s/%s", pubkeydir, fingerprint);
 553                 /* check if entry in pubkeydir exists */
 554                 if (stat(rfname, &st) == 0) {
 555                         if (_usign_key_is_revoked(fingerprint, pubkeydir)) {
 556                                 if (!quiet)
 557                                         fprintf(stdout, "existing revoker deadlink for key %s\n", fingerprint);
 558                                 continue;
 559                         };
 560
 561                         /* remove any other entry */
 562                         if (unlink(rfname))
 563                                 return -1;
 564                 }
 565
 566                 ret = symlink(".revoked.", rfname);
 567                 if (ret)
 568                         return ret;
 569
 570                 if (!quiet)
 571                         fprintf(stdout, "created revoker deadlink for key %s\n", fingerprint);
 572         };
 573
 574         return ret;
 575 }
 576
 577 /* load and verify certfile (and message) */
 578 static int cert_verify(const char *certfile, const char *pubkeyfile, const char *pubkeydir, const char *msgfile) {
 579         static LIST_HEAD(certchain);
 580
 581         if (cert_load(certfile, &certchain)) {
 582                 fprintf(stderr, "cannot parse cert\n");
 583                 return 1;
 584         }
 585
 586         return chain_verify(msgfile, pubkeyfile, pubkeydir, &certchain);
 587 }
 588
 589 /* output help */
 590 static int usage(const char *cmd)
 591 {
 592         fprintf(stderr,
 593                 "Usage: %s <command> <options>\n"
 594                 "Commands:\n"
 595                 "  -A:                  append signature (needs -c and -x)\n"
 596                 "  -D:                  dump (needs -c)\n"
 597                 "  -I:                  issue cert and revoker (needs -c and -p and -s)\n"
 598                 "  -R:                  process revoker certificate (needs -c and -P)\n"
 599                 "  -V:                  verify (needs -c and -p|-P, may have -m)\n"
 600                 "Options:\n"
 601                 "  -c <file>:           certificate file\n"
 602                 "  -m <file>:           message file (verify only)\n"
 603                 "  -p <file>:           public key file\n"
 604                 "  -P <path>:           public key directory (verify only)\n"
 605                 "  -q:                  quiet (do not print verification result, use return code only)\n"
 606                 "  -s <file>:           secret key file (issue only)\n"
 607                 "  -x <file>:           signature file\n"
 608                 "\n",
 609                 cmd);
 610         return 1;
 611 }
 612
 613 /* parse command line options and call functions */
 614 int main(int argc, char *argv[]) {
 615         int ch;
 616         const char *msgfile = NULL;
 617         const char *sigfile = NULL;
 618         const char *pubkeyfile = NULL;
 619         const char *pubkeydir = NULL;
 620         const char *certfile = NULL;
 621         const char *seckeyfile = NULL;
 622
 623         quiet = false;
 624         while ((ch = getopt(argc, argv, "ADIRVc:m:p:P:qs:x:")) != -1) {
 625                 switch (ch) {
 626                 case 'A':
 627                         if (cmd != CMD_NONE)
 628                                 return usage(argv[0]);
 629                         cmd = CMD_APPEND;
 630                         break;
 631                 case 'D':
 632                         if (cmd != CMD_NONE)
 633                                 return usage(argv[0]);
 634                         cmd = CMD_DUMP;
 635                         break;
 636                 case 'I':
 637                         if (cmd != CMD_NONE)
 638                                 return usage(argv[0]);
 639                         cmd = CMD_ISSUE;
 640                         break;
 641                 case 'R':
 642                         if (cmd != CMD_NONE)
 643                                 return usage(argv[0]);
 644                         cmd = CMD_REVOKE;
 645                         break;
 646                 case 'V':
 647                         if (cmd != CMD_NONE)
 648                                 return usage(argv[0]);
 649                         cmd = CMD_VERIFY;
 650                         break;
 651                 case 'c':
 652                         if (certfile || cmd == CMD_NONE)
 653                                 return usage(argv[0]);
 654                         certfile = optarg;
 655                         break;
 656                 case 'm':
 657                         if (msgfile || cmd != CMD_VERIFY)
 658                                 return usage(argv[0]);
 659                         msgfile = optarg;
 660                         break;
 661                 case 'p':
 662                         if (pubkeyfile || (cmd != CMD_VERIFY && cmd != CMD_ISSUE) || cmd == CMD_NONE)
 663                                 return usage(argv[0]);
 664                         pubkeyfile = optarg;
 665                         break;
 666                 case 'P':
 667                         if (pubkeydir || (cmd != CMD_VERIFY && cmd != CMD_REVOKE) || cmd == CMD_NONE)
 668                                 return usage(argv[0]);
 669                         pubkeydir = optarg;
 670                         break;
 671                 case 'q':
 672                         if (quiet || cmd == CMD_NONE)
 673                                 return usage(argv[0]);
 674                         quiet = true;
 675                         break;
 676                 case 's':
 677                         if (seckeyfile || cmd != CMD_ISSUE || cmd == CMD_NONE)
 678                                 return usage(argv[0]);
 679                         seckeyfile = optarg;
 680                         break;
 681                 case 'x':
 682                         if (sigfile || cmd != CMD_APPEND || cmd == CMD_NONE)
 683                                 return usage(argv[0]);
 684                         sigfile = optarg;
 685                         break;
 686                 default:
 687                         return usage(argv[0]);
 688                 }
 689         }
 690
 691         switch (cmd) {
 692         case CMD_APPEND:
 693                 if (certfile && sigfile)
 694                         return cert_append(certfile, sigfile);
 695                 else
 696                         return usage(argv[0]);
 697         case CMD_DUMP:
 698                 if (certfile)
 699                         return cert_dump(certfile);
 700                 else
 701                         return usage(argv[0]);
 702         case CMD_ISSUE:
 703                 if (certfile && pubkeyfile && seckeyfile)
 704                         return cert_issue(certfile, pubkeyfile, seckeyfile);
 705                 else
 706                         return usage(argv[0]);
 707         case CMD_REVOKE:
 708                 if (certfile && pubkeydir)
 709                         return cert_process_revoker(certfile, pubkeydir);
 710                 else
 711                         return usage(argv[0]);
 712         case CMD_VERIFY:
 713                 if (certfile && (pubkeyfile || pubkeydir))
 714                         return cert_verify(certfile, pubkeyfile, pubkeydir, msgfile);
 715                 else
 716                         return usage(argv[0]);
 717         case CMD_NONE:
 718                 return usage(argv[0]);
 719         }
 720
 721         /* unreachable */
 722         return usage(argv[0]);
 723 }