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