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         bool                             inpacket = false;
 198
 199         if (packets == NULL)
 200                 return ONAK_E_INVALID_PARAM;
 201
 202         curpacket = *packets;
 203         if (curpacket != NULL) {
 204                 while (curpacket->next != NULL) {
 205                         curpacket = curpacket->next;
 206                 }
 207         }
 208
 209         while (!rc && (maxnum == 0 || keys < maxnum) &&
 210                         !getchar_func(ctx, 1, &curchar)) {
 211                 if (!inpacket && (curchar & 0x80)) {
 212                         /*
 213                          * New packet. Record the fact we're in a packet and
 214                          * allocate memory for it.
 215                          */
 216                         inpacket = true;
 217                         if (curpacket != NULL) {
 218                                 curpacket->next = malloc(sizeof (*curpacket));
 219                                 packetend = &curpacket->next;
 220                                 curpacket = curpacket->next;
 221                         } else {
 222                                 *packets = curpacket =
 223                                         malloc(sizeof (*curpacket));
 224                                 packetend = packets;
 225                         }
 226                         memset(curpacket, 0, sizeof(*curpacket));
 227                         curpacket->packet =
 228                                 malloc(sizeof (*curpacket->packet));
 229                         memset(curpacket->packet, 0,
 230                                         sizeof(*curpacket->packet));
 231
 232                         curpacket->packet->newformat = (curchar & 0x40);
 233
 234                         /*
 235                          * TODO: Better error checking on getchar_func.
 236                          */
 237                         if (curpacket->packet->newformat) {
 238                                 curpacket->packet->tag = (curchar & 0x3F);
 239                                 rc = getchar_func(ctx, 1, &curchar);
 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                                         rc = getchar_func(ctx, 1, &curchar);
 259                                         curpacket->packet->length = curchar;
 260                                         curpacket->packet->length <<= 8;
 261                                         rc = getchar_func(ctx, 1, &curchar);
 262                                         curpacket->packet->length += curchar;
 263                                         curpacket->packet->length <<= 8;
 264                                         rc = getchar_func(ctx, 1, &curchar);
 265                                         curpacket->packet->length += curchar;
 266                                         curpacket->packet->length <<= 8;
 267                                         rc = getchar_func(ctx, 1, &curchar);
 268                                         curpacket->packet->length += curchar;
 269                                 }
 270                         } else {
 271                                 curpacket->packet->tag = (curchar & 0x3C) >> 2;
 272                                 switch (curchar & 3) {
 273                                 case 0:
 274                                         rc = getchar_func(ctx, 1, &curchar);
 275                                         curpacket->packet->length = curchar;
 276                                         break;
 277                                 case 1:
 278                                         rc = getchar_func(ctx, 1, &curchar);
 279                                         curpacket->packet->length = curchar;
 280                                         curpacket->packet->length <<= 8;
 281                                         rc = getchar_func(ctx, 1, &curchar);
 282                                         curpacket->packet->length += curchar;
 283                                         break;
 284                                 case 2:
 285                                         rc = getchar_func(ctx, 1, &curchar);
 286                                         curpacket->packet->length =
 287                                                 (curchar << 24);
 288                                         rc = getchar_func(ctx, 1, &curchar);
 289                                         curpacket->packet->length +=
 290                                                 (curchar << 16);
 291                                         rc = getchar_func(ctx, 1, &curchar);
 292                                         curpacket->packet->length +=
 293                                                 (curchar << 8);
 294                                         rc = getchar_func(ctx, 1, &curchar);
 295                                         curpacket->packet->length += curchar;
 296                                         break;
 297                                 case 3:
 298                                         rc = ONAK_E_UNSUPPORTED_FEATURE;
 299                                         free(curpacket->packet);
 300                                         curpacket->packet = NULL;
 301                                         break;
 302                                 }
 303                         }
 304
 305                         if (rc == 0) {
 306                                 if (curpacket->packet->tag ==
 307                                                 OPENPGP_PACKET_PUBLICKEY) {
 308                                         keys++;
 309                                 }
 310                                 curpacket->packet->data =
 311                                         malloc(curpacket->packet->length *
 312                                         sizeof(unsigned char));
 313                                 if (curpacket->packet->data == NULL) {
 314                                         rc = ONAK_E_NOMEM;
 315                                 } else {
 316                                         rc = getchar_func(ctx,
 317                                                 curpacket->packet->length,
 318                                                 curpacket->packet->data);
 319                                 }
 320                         }
 321                         inpacket = false;
 322                 } else {
 323                         rc = ONAK_E_INVALID_PKT;
 324                 }
 325         }
 326
 327         /* Trim the last packet if it doesn't actually exist */
 328         if (packetend != NULL && (*packetend)->packet == NULL) {
 329                 free(*packetend);
 330                 *packetend = NULL;
 331         }
 332
 333         return (rc);
 334 }
 335
 336 /**
 337  *      write_openpgp_stream - Reads a stream of OpenPGP packets.
 338  *      @putchar_func: The function to put the next character to the stream.
 339  *      @ctx: A pointer to the context structure for putchar_func.
 340  *      @packets: The list of packets.
 341  *
 342  *      This function uses putchar_func to write characters to an OpenPGP
 343  *      packet stream from a linked list of packets.
 344  */
 345 onak_status_t write_openpgp_stream(int (*putchar_func)(void *ctx, size_t count,
 346                                                 void *c),
 347                                 void *ctx,
 348                                 struct openpgp_packet_list *packets)
 349 {
 350         unsigned char   curchar = 0;
 351
 352         while (packets != NULL) {
 353                 curchar = 0x80;
 354                 if (packets->packet->newformat) {
 355                         curchar |= 0x40;
 356                         curchar |= packets->packet->tag;
 357                         putchar_func(ctx, 1, &curchar);
 358
 359                         if (packets->packet->length < 192) {
 360                                 curchar = packets->packet->length;
 361                                 putchar_func(ctx, 1, &curchar);
 362                         } else if (packets->packet->length > 191 &&
 363                                 packets->packet->length < 8383) {
 364                                 curchar = (((packets->packet->length - 192) &
 365                                          0xFF00) >> 8) + 192;
 366                                 putchar_func(ctx, 1, &curchar);
 367
 368                                 curchar = (packets->packet->length - 192) &
 369                                          0xFF;
 370                                 putchar_func(ctx, 1, &curchar);
 371                         } else if (packets->packet->length > 8382 &&
 372                                 packets->packet->length < 0xFFFFFFFF) {
 373                                 curchar = 255;
 374                                 putchar_func(ctx, 1, &curchar);
 375
 376                                 curchar = (packets->packet->length >> 24);
 377                                 curchar &= 0xFF;
 378                                 putchar_func(ctx, 1, &curchar);
 379
 380                                 curchar = (packets->packet->length >> 16);
 381                                 curchar &= 0xFF;
 382                                 putchar_func(ctx, 1, &curchar);
 383
 384                                 curchar = (packets->packet->length >> 8);
 385                                 curchar &= 0xFF;
 386                                 putchar_func(ctx, 1, &curchar);
 387
 388                                 curchar = packets->packet->length;
 389                                 curchar &= 0xFF;
 390                                 putchar_func(ctx, 1, &curchar);
 391                         } else {
 392                                 return ONAK_E_UNSUPPORTED_FEATURE;
 393                         }
 394                 } else {
 395                         curchar |= (packets->packet->tag << 2);
 396                         if (packets->packet->length < 256) {
 397                                 putchar_func(ctx, 1, &curchar);
 398                                 curchar = packets->packet->length;
 399                                 putchar_func(ctx, 1, &curchar);
 400                         } else if (packets->packet->length < 0x10000) {
 401                                 curchar |= 1;
 402                                 putchar_func(ctx, 1, &curchar);
 403                                 curchar = packets->packet->length >> 8;
 404                                 putchar_func(ctx, 1, &curchar);
 405                                 curchar = packets->packet->length & 0xFF;
 406                                 putchar_func(ctx, 1, &curchar);
 407                         } else {
 408                                 curchar |= 2;
 409                                 putchar_func(ctx, 1, &curchar);
 410                                 curchar = packets->packet->length >> 24;
 411                                 putchar_func(ctx, 1, &curchar);
 412                                 curchar = (packets->packet->length >> 16) & 0xFF;
 413                                 putchar_func(ctx, 1, &curchar);
 414                                 curchar = (packets->packet->length >> 8) & 0xFF;
 415                                 putchar_func(ctx, 1, &curchar);
 416                                 curchar = packets->packet->length & 0xFF;
 417                                 putchar_func(ctx, 1, &curchar);
 418                         }
 419                 }
 420
 421                 putchar_func(ctx, packets->packet->length,
 422                                 packets->packet->data);
 423                 packets = packets->next;
 424         }
 425
 426         return ONAK_E_OK;
 427 }
 428
 429 /**
 430  *      flatten_publickey - Convert a publickey to an OpenPGP packet list.
 431  *      @key: The public key.
 432  *      @packets: The outputted packet list.
 433  *
 434  *      This function converts public key structure to a linked list of OpenPGP
 435  *      packets ready for outputing or storage.
 436  */
 437 int flatten_publickey(struct openpgp_publickey *key,
 438                         struct openpgp_packet_list **packets,
 439                         struct openpgp_packet_list **list_end)
 440 {
 441         struct openpgp_signedpacket_list        *tmpsignedlist = NULL;
 442         struct openpgp_packet_list              *tmplist = NULL;
 443
 444         while (key != NULL) {
 445                 /*
 446                  * First write the public key packet out.
 447                  */
 448                 ADD_PACKET_TO_LIST((*list_end), packet_dup(key->publickey));
 449                 if (*packets == NULL) {
 450                         *packets = *list_end;
 451                 }
 452
 453                 /*
 454                  * Now do any signatures on the main key.
 455                  */
 456                 for (tmplist = key->sigs; tmplist != NULL;
 457                                 tmplist = tmplist->next) {
 458                         ADD_PACKET_TO_LIST((*list_end),
 459                                         packet_dup(tmplist->packet));
 460                 }
 461
 462                 /*
 463                  * Output any UIDs along with their signatures.
 464                  */
 465                 for (tmpsignedlist = key->uids; tmpsignedlist != NULL;
 466                                 tmpsignedlist = tmpsignedlist->next) {
 467
 468                         ADD_PACKET_TO_LIST((*list_end),
 469                                 packet_dup(tmpsignedlist->packet));
 470                         for (tmplist = tmpsignedlist->sigs; tmplist != NULL;
 471                                         tmplist = tmplist->next) {
 472                                 ADD_PACKET_TO_LIST((*list_end),
 473                                         packet_dup(tmplist->packet));
 474                         }
 475                 }
 476
 477                 /*
 478                  * Output any subkeys along with their signatures.
 479                  */
 480                 for (tmpsignedlist = key->subkeys; tmpsignedlist != NULL;
 481                                 tmpsignedlist = tmpsignedlist->next) {
 482
 483                         ADD_PACKET_TO_LIST((*list_end),
 484                                 packet_dup(tmpsignedlist->packet));
 485                         for (tmplist = tmpsignedlist->sigs; tmplist != NULL;
 486                                         tmplist = tmplist->next) {
 487                                 ADD_PACKET_TO_LIST((*list_end),
 488                                         packet_dup(tmplist->packet));
 489                         }
 490                 }
 491                 key = key->next;
 492         }
 493         return 0;
 494 }