parsekey.c

   1 /*
   2  * parsekey.c - Routines to parse an OpenPGP key.
   3  *
   4  * Copyright 2002-2004,2007-2008,2011 Jonathan McDowell <noodles@earth.li>
   5  *
   6  * This program is free software: you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; version 2 of the License.
   9  *
  10  * This program is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program; if not, write to the Free Software Foundation, Inc., 51
  17  * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  */
  19
  20 #include <stdbool.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24
  25 #include "keystructs.h"
  26 #include "ll.h"
  27 #include "mem.h"
  28 #include "onak.h"
  29 #include "openpgp.h"
  30 #include "parsekey.h"
  31
  32 /**
  33  *      parse_keys - Process a stream of packets for public keys + sigs.
  34  *      @packets: The packet list to parse.
  35  *      @keys: The returned list of public keys.
  36  *
  37  *      This function takes an list of OpenPGP packets and attempts to parse it
  38  *      into a list of public keys with signatures and subkeys.
  39  *
  40  *      Returns a count of how many keys we parsed.
  41  */
  42 int parse_keys(struct openpgp_packet_list *packets,
  43                 struct openpgp_publickey **keys)
  44 {
  45         struct openpgp_publickey *curkey = NULL;
  46         int count;
  47
  48         count = 0;
  49
  50         /*
  51          * If keys already has some keys in it then set curkey to the last one
  52          * so we add to the end of the list.
  53          */
  54         for (curkey = *keys; curkey != NULL && curkey->next != NULL;
  55                         curkey = curkey->next) ;
  56
  57         while (packets != NULL) {
  58                 switch (packets->packet->tag) {
  59                 case OPENPGP_PACKET_SIGNATURE:
  60                         /*
  61                          * It's a signature packet. Add it to either the public
  62                          * key, to the current UID or the current subkey.
  63                          */
  64                         if (curkey == NULL)
  65                                 return ONAK_E_INVALID_PARAM;
  66                         if (curkey->subkeys != NULL) {
  67                                 ADD_PACKET_TO_LIST_END(curkey->last_subkey,
  68                                         sig,
  69                                         packet_dup(packets->packet));
  70                         } else if (curkey->uids != NULL) {
  71                                 ADD_PACKET_TO_LIST_END(curkey->last_uid,
  72                                         sig,
  73                                         packet_dup(packets->packet));
  74                         } else {
  75                                 ADD_PACKET_TO_LIST_END(curkey,
  76                                         sig,
  77                                         packet_dup(packets->packet));
  78                                 /*
  79                                  * This is a signature on the public key; check
  80                                  * if it's a revocation.
  81                                  */
  82                                 if (packets->packet->data[0] == 3 &&
  83                                         packets->packet->data[2] ==
  84                                                 OPENPGP_SIGTYPE_KEY_REV) {
  85                                         /*
  86                                          * Type 3 key, 0x20 == revocation
  87                                          */
  88                                         curkey->revoked = true;
  89                                 } else if (packets->packet->data[0] == 4 &&
  90                                         packets->packet->data[1] ==
  91                                                 OPENPGP_SIGTYPE_KEY_REV) {
  92                                         /*
  93                                          * Type 4 key, 0x20 == revocation
  94                                          */
  95                                         curkey->revoked = true;
  96                                 }
  97                         }
  98                         break;
  99                 case OPENPGP_PACKET_PUBLICKEY:
 100                         /*
 101                          * It's a public key packet, so start a new key in our
 102                          * list.
 103                          */
 104                         if (curkey != NULL) {
 105                                 curkey->next = malloc(sizeof (*curkey));
 106                                 curkey = curkey->next;
 107                         } else {
 108                                 *keys = curkey =
 109                                         malloc(sizeof (*curkey));
 110                         }
 111                         memset(curkey, 0, sizeof(*curkey));
 112                         curkey->publickey = packet_dup(packets->packet);
 113                         count++;
 114                         break;
 115                 case OPENPGP_PACKET_UID:
 116                 case OPENPGP_PACKET_UAT:
 117                         /*
 118                          * It's a UID packet (or a photo id, which is similar).
 119                          */
 120                         if (curkey == NULL)
 121                                 return ONAK_E_INVALID_PARAM;
 122                         if (curkey->subkeys != NULL)
 123                                 return ONAK_E_INVALID_PARAM;
 124                         ADD_PACKET_TO_LIST_END(curkey,
 125                                 uid,
 126                                 packet_dup(packets->packet));
 127                         break;
 128                 case OPENPGP_PACKET_PUBLICSUBKEY:
 129                         /*
 130                          * It's a subkey packet.
 131                          */
 132                         if (curkey == NULL)
 133                                 return ONAK_E_INVALID_PARAM;
 134                         ADD_PACKET_TO_LIST_END(curkey,
 135                                 subkey,
 136                                 packet_dup(packets->packet));
 137                         break;
 138                 case OPENPGP_PACKET_TRUST:
 139                 case OPENPGP_PACKET_COMMENT:
 140                         /*
 141                          * One of:
 142                          *
 143                          * Trust packet. Ignore.
 144                          * Comment packet. Ignore.
 145                          */
 146                         break;
 147                 default:
 148                         /* Unsupported packet. Do what? Ignore for now. */
 149                         break;
 150                 }
 151                 packets = packets->next;
 152         }
 153
 154         return count;
 155 }
 156
 157 /**
 158  *      debug_packet - Print debug info about a packet
 159  *      @packet: The packet to display.
 160  *
 161  *      This function takes an OpenPGP packet and displays some information
 162  *      about it to stdout. Useful for debugging purposes or curiousity about
 163  *      an OpenPGP packet stream.
 164  */
 165 int debug_packet(struct openpgp_packet *packet)
 166 {
 167         printf("\tNew format: %d, Tag: %u, Length: %zd\n",
 168                         packet->newformat,
 169                         packet->tag,
 170                         packet->length);
 171
 172         return 0;
 173 }
 174
 175 /**
 176  *      read_openpgp_stream - Reads a stream of OpenPGP packets.
 177  *      @getchar_func: The function to get the next character from the stream.
 178  *      @ctx: A pointer to the context structure for getchar_func.
 179  *      @packets: The outputted list of packets.
 180  *      @maxnum: The maximum number of keys to read. 0 means unlimited.
 181  *
 182  *      This function uses getchar_func to read characters from an OpenPGP
 183  *      packet stream and reads the packets into a linked list of packets
 184  *      ready for parsing as a public key or whatever.
 185  */
 186 onak_status_t read_openpgp_stream(int (*getchar_func)(void *ctx, size_t count,
 187                                 void *c),
 188                                 void *ctx,
 189                                 struct openpgp_packet_list **packets,
 190                                 int maxnum)
 191 {
 192         unsigned char                    curchar = 0;
 193         struct openpgp_packet_list      *curpacket = NULL, **packetend = NULL;
 194         onak_status_t                    rc = ONAK_E_OK;
 195         int                              keys = 0;
 196
 197         if (packets == NULL)
 198                 return ONAK_E_INVALID_PARAM;
 199
 200         curpacket = *packets;
 201         if (curpacket != NULL) {
 202                 while (curpacket->next != NULL) {
 203                         curpacket = curpacket->next;
 204                 }
 205         }
 206
 207         while (rc == ONAK_E_OK && (maxnum == 0 || keys < maxnum) &&
 208                         !getchar_func(ctx, 1, &curchar)) {
 209                 if (curchar & 0x80) {
 210                         /*
 211                          * New packet. Allocate memory for it.
 212                          */
 213                         if (curpacket != NULL) {
 214                                 curpacket->next = malloc(sizeof (*curpacket));
 215                                 packetend = &curpacket->next;
 216                                 curpacket = curpacket->next;
 217                         } else {
 218                                 *packets = curpacket =
 219                                         malloc(sizeof (*curpacket));
 220                                 packetend = packets;
 221                         }
 222                         memset(curpacket, 0, sizeof(*curpacket));
 223                         curpacket->packet =
 224                                 malloc(sizeof (*curpacket->packet));
 225                         memset(curpacket->packet, 0,
 226                                         sizeof(*curpacket->packet));
 227
 228                         curpacket->packet->newformat = (curchar & 0x40);
 229
 230                         /*
 231                          * TODO: Better error checking on getchar_func.
 232                          */
 233                         if (curpacket->packet->newformat) {
 234                                 curpacket->packet->tag = (curchar & 0x3F);
 235                                 if (getchar_func(ctx, 1, &curchar)) {
 236                                         rc = ONAK_E_INVALID_PKT;
 237                                         break;
 238                                 }
 239                                 curpacket->packet->length = curchar;
 240                                 if (curpacket->packet->length > 191 &&
 241                                         curpacket->packet->length < 224) {
 242                                         rc = getchar_func(ctx, 1, &curchar);
 243                                         curpacket->packet->length -= 192;
 244                                         curpacket->packet->length <<= 8;
 245                                         curpacket->packet->length += curchar;
 246                                         curpacket->packet->length += 192;
 247                                 } else if (curpacket->packet->length > 223 &&
 248                                         curpacket->packet->length < 255) {
 249                                         free(curpacket->packet);
 250                                         curpacket->packet = NULL;
 251                                         rc = ONAK_E_UNSUPPORTED_FEATURE;
 252                                 } else if (curpacket->packet->length == 255) {
 253                                         /*
 254                                          * 5 byte length; ie 255 followed by 3
 255                                          * bytes of MSB length.
 256                                          */
 257                                         if (getchar_func(ctx, 1, &curchar)) {
 258                                                 rc = ONAK_E_INVALID_PKT;
 259                                                 break;
 260                                         }
 261                                         curpacket->packet->length = curchar;
 262                                         curpacket->packet->length <<= 8;
 263                                         if (getchar_func(ctx, 1, &curchar)) {
 264                                                 rc = ONAK_E_INVALID_PKT;
 265                                                 break;
 266                                         }
 267                                         curpacket->packet->length += curchar;
 268                                         curpacket->packet->length <<= 8;
 269                                         if (getchar_func(ctx, 1, &curchar)) {
 270                                                 rc = ONAK_E_INVALID_PKT;
 271                                                 break;
 272                                         }
 273                                         curpacket->packet->length += curchar;
 274                                         curpacket->packet->length <<= 8;
 275                                         if (getchar_func(ctx, 1, &curchar)) {
 276                                                 rc = ONAK_E_INVALID_PKT;
 277                                                 break;
 278                                         }
 279                                         curpacket->packet->length += curchar;
 280                                 }
 281                         } else {
 282                                 curpacket->packet->tag = (curchar & 0x3C) >> 2;
 283                                 switch (curchar & 3) {
 284                                 case 0:
 285                                         if (getchar_func(ctx, 1, &curchar)) {
 286                                                 rc = ONAK_E_INVALID_PKT;
 287                                                 break;
 288                                         }
 289                                         curpacket->packet->length = curchar;
 290                                         break;
 291                                 case 1:
 292                                         if (getchar_func(ctx, 1, &curchar)) {
 293                                                 rc = ONAK_E_INVALID_PKT;
 294                                                 break;
 295                                         }
 296                                         curpacket->packet->length = curchar;
 297                                         curpacket->packet->length <<= 8;
 298                                         if (getchar_func(ctx, 1, &curchar)) {
 299                                                 rc = ONAK_E_INVALID_PKT;
 300                                                 break;
 301                                         }
 302                                         curpacket->packet->length += curchar;
 303                                         break;
 304                                 case 2:
 305                                         if (getchar_func(ctx, 1, &curchar)) {
 306                                                 rc = ONAK_E_INVALID_PKT;
 307                                                 break;
 308                                         }
 309                                         curpacket->packet->length =
 310                                                 ((unsigned) curchar << 24);
 311                                         if (getchar_func(ctx, 1, &curchar)) {
 312                                                 rc = ONAK_E_INVALID_PKT;
 313                                                 break;
 314                                         }
 315                                         curpacket->packet->length +=
 316                                                 (curchar << 16);
 317                                         if (getchar_func(ctx, 1, &curchar)) {
 318                                                 rc = ONAK_E_INVALID_PKT;
 319                                                 break;
 320                                         }
 321                                         curpacket->packet->length +=
 322                                                 (curchar << 8);
 323                                         if (getchar_func(ctx, 1, &curchar)) {
 324                                                 rc = ONAK_E_INVALID_PKT;
 325                                                 break;
 326                                         }
 327                                         curpacket->packet->length += curchar;
 328                                         break;
 329                                 case 3:
 330                                         rc = ONAK_E_UNSUPPORTED_FEATURE;
 331                                         free(curpacket->packet);
 332                                         curpacket->packet = NULL;
 333                                         break;
 334                                 }
 335                         }
 336
 337                         if (rc == 0) {
 338                                 if (curpacket->packet->tag ==
 339                                                 OPENPGP_PACKET_PUBLICKEY) {
 340                                         keys++;
 341                                 }
 342                                 curpacket->packet->data =
 343                                         malloc(curpacket->packet->length *
 344                                         sizeof(unsigned char));
 345                                 if (curpacket->packet->data == NULL) {
 346                                         rc = ONAK_E_NOMEM;
 347                                 } else {
 348                                         rc = getchar_func(ctx,
 349                                                 curpacket->packet->length,
 350                                                 curpacket->packet->data);
 351                                 }
 352                         }
 353                 } else {
 354                         rc = ONAK_E_INVALID_PKT;
 355                 }
 356                 if (rc == ONAK_E_OK) {
 357                         /* Make sure the packet version is sane */
 358                         switch (curpacket->packet->tag) {
 359                         case OPENPGP_PACKET_ENCRYPTED_MDC:
 360                                 /* These packets must be v1 */
 361                                 if (curpacket->packet->data[0] != 1) {
 362                                         rc = ONAK_E_INVALID_PKT;
 363                                 }
 364                                 break;
 365                         case OPENPGP_PACKET_PKSESSIONKEY:
 366                         case OPENPGP_PACKET_ONEPASSSIG:
 367                                 /* These packets must be v3 */
 368                                 if (curpacket->packet->data[0] != 3) {
 369                                         rc = ONAK_E_INVALID_PKT;
 370                                 }
 371                                 break;
 372                         case OPENPGP_PACKET_SYMSESSIONKEY:
 373                                 /* These packets must be v4 */
 374                                 if (curpacket->packet->data[0] != 4) {
 375                                         rc = ONAK_E_INVALID_PKT;
 376                                 }
 377                                 break;
 378                         case OPENPGP_PACKET_SIGNATURE:
 379                         case OPENPGP_PACKET_SECRETKEY:
 380                         case OPENPGP_PACKET_PUBLICKEY:
 381                                 /* Must be v2 -> v4 */
 382                                 if (curpacket->packet->data[0] < 2 ||
 383                                         curpacket->packet->data[0] > 4) {
 384                                         rc = ONAK_E_INVALID_PKT;
 385                                 }
 386                                 break;
 387                         default:
 388                                 break;
 389                         }
 390                 }
 391         }
 392
 393         if (packetend != NULL) {
 394                 if ((*packetend)->packet != NULL) {
 395                         /* If we got an invalid final packet, discard it. */
 396                         if ((*packetend)->packet->data != NULL &&
 397                                         rc != ONAK_E_OK) {
 398                                 free((*packetend)->packet->data);
 399                                 (*packetend)->packet->data = NULL;
 400                         }
 401                         /* If we didn't get any data, clean it up. */
 402                         if ((*packetend)->packet->data == NULL) {
 403                                 free((*packetend)->packet);
 404                                 (*packetend)->packet = NULL;
 405                         }
 406                 }
 407                 /* Trim the last packet if it doesn't actually exist */
 408                 if ((*packetend)->packet == NULL) {
 409                         free(*packetend);
 410                         *packetend = NULL;
 411                 }
 412         }
 413
 414         return (rc);
 415 }
 416
 417 /**
 418  *      write_openpgp_stream - Reads a stream of OpenPGP packets.
 419  *      @putchar_func: The function to put the next character to the stream.
 420  *      @ctx: A pointer to the context structure for putchar_func.
 421  *      @packets: The list of packets.
 422  *
 423  *      This function uses putchar_func to write characters to an OpenPGP
 424  *      packet stream from a linked list of packets.
 425  */
 426 onak_status_t write_openpgp_stream(int (*putchar_func)(void *ctx, size_t count,
 427                                                 void *c),
 428                                 void *ctx,
 429                                 struct openpgp_packet_list *packets)
 430 {
 431         unsigned char   curchar = 0;
 432
 433         while (packets != NULL) {
 434                 curchar = 0x80;
 435                 if (packets->packet->newformat) {
 436                         curchar |= 0x40;
 437                         curchar |= packets->packet->tag;
 438                         putchar_func(ctx, 1, &curchar);
 439
 440                         if (packets->packet->length < 192) {
 441                                 curchar = packets->packet->length;
 442                                 putchar_func(ctx, 1, &curchar);
 443                         } else if (packets->packet->length > 191 &&
 444                                 packets->packet->length < 8383) {
 445                                 curchar = (((packets->packet->length - 192) &
 446                                          0xFF00) >> 8) + 192;
 447                                 putchar_func(ctx, 1, &curchar);
 448
 449                                 curchar = (packets->packet->length - 192) &
 450                                          0xFF;
 451                                 putchar_func(ctx, 1, &curchar);
 452                         } else if (packets->packet->length > 8382 &&
 453                                 packets->packet->length < 0xFFFFFFFF) {
 454                                 curchar = 255;
 455                                 putchar_func(ctx, 1, &curchar);
 456
 457                                 curchar = (packets->packet->length >> 24);
 458                                 curchar &= 0xFF;
 459                                 putchar_func(ctx, 1, &curchar);
 460
 461                                 curchar = (packets->packet->length >> 16);
 462                                 curchar &= 0xFF;
 463                                 putchar_func(ctx, 1, &curchar);
 464
 465                                 curchar = (packets->packet->length >> 8);
 466                                 curchar &= 0xFF;
 467                                 putchar_func(ctx, 1, &curchar);
 468
 469                                 curchar = packets->packet->length;
 470                                 curchar &= 0xFF;
 471                                 putchar_func(ctx, 1, &curchar);
 472                         } else {
 473                                 return ONAK_E_UNSUPPORTED_FEATURE;
 474                         }
 475                 } else {
 476                         curchar |= (packets->packet->tag << 2);
 477                         if (packets->packet->length < 256) {
 478                                 putchar_func(ctx, 1, &curchar);
 479                                 curchar = packets->packet->length;
 480                                 putchar_func(ctx, 1, &curchar);
 481                         } else if (packets->packet->length < 0x10000) {
 482                                 curchar |= 1;
 483                                 putchar_func(ctx, 1, &curchar);
 484                                 curchar = packets->packet->length >> 8;
 485                                 putchar_func(ctx, 1, &curchar);
 486                                 curchar = packets->packet->length & 0xFF;
 487                                 putchar_func(ctx, 1, &curchar);
 488                         } else {
 489                                 curchar |= 2;
 490                                 putchar_func(ctx, 1, &curchar);
 491                                 curchar = packets->packet->length >> 24;
 492                                 putchar_func(ctx, 1, &curchar);
 493                                 curchar = (packets->packet->length >> 16) & 0xFF;
 494                                 putchar_func(ctx, 1, &curchar);
 495                                 curchar = (packets->packet->length >> 8) & 0xFF;
 496                                 putchar_func(ctx, 1, &curchar);
 497                                 curchar = packets->packet->length & 0xFF;
 498                                 putchar_func(ctx, 1, &curchar);
 499                         }
 500                 }
 501
 502                 putchar_func(ctx, packets->packet->length,
 503                                 packets->packet->data);
 504                 packets = packets->next;
 505         }
 506
 507         return ONAK_E_OK;
 508 }
 509
 510 /**
 511  *      flatten_publickey - Convert a publickey to an OpenPGP packet list.
 512  *      @key: The public key.
 513  *      @packets: The outputted packet list.
 514  *
 515  *      This function converts public key structure to a linked list of OpenPGP
 516  *      packets ready for outputing or storage.
 517  */
 518 int flatten_publickey(struct openpgp_publickey *key,
 519                         struct openpgp_packet_list **packets,
 520                         struct openpgp_packet_list **list_end)
 521 {
 522         struct openpgp_signedpacket_list        *tmpsignedlist = NULL;
 523         struct openpgp_packet_list              *tmplist = NULL;
 524
 525         while (key != NULL) {
 526                 /*
 527                  * First write the public key packet out.
 528                  */
 529                 ADD_PACKET_TO_LIST((*list_end), packet_dup(key->publickey));
 530                 if (*packets == NULL) {
 531                         *packets = *list_end;
 532                 }
 533
 534                 /*
 535                  * Now do any signatures on the main key.
 536                  */
 537                 for (tmplist = key->sigs; tmplist != NULL;
 538                                 tmplist = tmplist->next) {
 539                         ADD_PACKET_TO_LIST((*list_end),
 540                                         packet_dup(tmplist->packet));
 541                 }
 542
 543                 /*
 544                  * Output any UIDs along with their signatures.
 545                  */
 546                 for (tmpsignedlist = key->uids; tmpsignedlist != NULL;
 547                                 tmpsignedlist = tmpsignedlist->next) {
 548
 549                         ADD_PACKET_TO_LIST((*list_end),
 550                                 packet_dup(tmpsignedlist->packet));
 551                         for (tmplist = tmpsignedlist->sigs; tmplist != NULL;
 552                                         tmplist = tmplist->next) {
 553                                 ADD_PACKET_TO_LIST((*list_end),
 554                                         packet_dup(tmplist->packet));
 555                         }
 556                 }
 557
 558                 /*
 559                  * Output any subkeys along with their signatures.
 560                  */
 561                 for (tmpsignedlist = key->subkeys; tmpsignedlist != NULL;
 562                                 tmpsignedlist = tmpsignedlist->next) {
 563
 564                         ADD_PACKET_TO_LIST((*list_end),
 565                                 packet_dup(tmpsignedlist->packet));
 566                         for (tmplist = tmpsignedlist->sigs; tmplist != NULL;
 567                                         tmplist = tmplist->next) {
 568                                 ADD_PACKET_TO_LIST((*list_end),
 569                                         packet_dup(tmplist->packet));
 570                         }
 571                 }
 572                 key = key->next;
 573         }
 574         return 0;
 575 }