parsekey.c

   1 /*
   2  * parsekey.c - Routines to parse an OpenPGP key.
   3  *
   4  * Jonathan McDowell <noodles@earth.li>
   5  *
   6  * Copyright 2002 Project Purple
   7  *
   8  * $Id: parsekey.c,v 1.18 2004/01/04 18:47:35 noodles Exp $
   9  */
  10
  11 #include <assert.h>
  12 #include <stdbool.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16
  17 #include "keyid.h"
  18 #include "keystructs.h"
  19 #include "ll.h"
  20 #include "log.h"
  21 #include "mem.h"
  22 #include "parsekey.h"
  23
  24 /**
  25  *      parse_keys - Process a stream of packets for public keys + sigs.
  26  *      @packets: The packet list to parse.
  27  *      @keys: The returned list of public keys.
  28  *
  29  *      This function takes an list of OpenPGP packets and attempts to parse it
  30  *      into a list of public keys with signatures and subkeys.
  31  *
  32  *      Returns a count of how many keys we parsed.
  33  */
  34 int parse_keys(struct openpgp_packet_list *packets,
  35                 struct openpgp_publickey **keys)
  36 {
  37         struct openpgp_publickey *curkey = NULL;
  38         int count;
  39
  40         count = 0;
  41
  42         /*
  43          * If keys already has some keys in it then set curkey to the last one
  44          * so we add to the end of the list.
  45          */
  46         for (curkey = *keys; curkey != NULL && curkey->next != NULL;
  47                         curkey = curkey->next) ;
  48
  49         while (packets != NULL) {
  50                 switch (packets->packet->tag) {
  51                 case 2:
  52                         /*
  53                          * It's a signature packet. Add it to either the public
  54                          * key (it should be a revocation), to the current UID
  55                          * or the current subkey.
  56                          */
  57                         assert(curkey != NULL);
  58                         if (curkey->subkeys != NULL) {
  59                                 ADD_PACKET_TO_LIST_END(curkey->last_subkey,
  60                                         sig,
  61                                         packet_dup(packets->packet));
  62                         } else if (curkey->uids != NULL) {
  63                                 ADD_PACKET_TO_LIST_END(curkey->last_uid,
  64                                         sig,
  65                                         packet_dup(packets->packet));
  66                         } else {
  67                                 ADD_PACKET_TO_LIST_END(curkey,
  68                                         revocation,
  69                                         packet_dup(packets->packet));
  70                         }
  71                         break;
  72                 case 6:
  73                         /*
  74                          * It's a public key packet, so start a new key in our
  75                          * list.
  76                          */
  77                         if (curkey != NULL) {
  78                                 curkey->next = malloc(sizeof (*curkey));
  79                                 curkey = curkey->next;
  80                         } else {
  81                                 *keys = curkey =
  82                                         malloc(sizeof (*curkey));
  83                         }
  84                         memset(curkey, 0, sizeof(*curkey));
  85                         curkey->publickey = packet_dup(packets->packet);
  86                         count++;
  87                         break;
  88                 case 13:
  89                 case 17:
  90                         /*
  91                          * It's a UID packet (or a photo id, which is similar).
  92                          */
  93                         assert(curkey != NULL);
  94                         assert(curkey->subkeys == NULL);
  95                         ADD_PACKET_TO_LIST_END(curkey,
  96                                 uid,
  97                                 packet_dup(packets->packet));
  98                         break;
  99                 case 14:
 100                         /*
 101                          * It's a subkey packet.
 102                          */
 103                         assert(curkey != NULL);
 104                         ADD_PACKET_TO_LIST_END(curkey,
 105                                 subkey,
 106                                 packet_dup(packets->packet));
 107                         break;
 108                 case 12:
 109                 case 61:
 110                         /*
 111                          * One of:
 112                          *
 113                          * Trust packet. Ignore.
 114                          * Comment packet. Ignore.
 115                          */
 116                         break;
 117                 default:
 118                         logthing(LOGTHING_ERROR,
 119                                         "Unsupported packet type: %d",
 120                                         packets->packet->tag);
 121                 }
 122                 packets = packets->next;
 123         }
 124
 125         return count;
 126 }
 127
 128 /**
 129  *      debug_packet - Print debug info about a packet
 130  *      @packet: The packet to display.
 131  *
 132  *      This function takes an OpenPGP packet and displays some information
 133  *      about it to stdout. Useful for debugging purposes or curiousity about
 134  *      an OpenPGP packet stream.
 135  */
 136 int debug_packet(struct openpgp_packet *packet)
 137 {
 138         printf("\tNew format: %d, Tag: %u, Length: %d\n",
 139                         packet->newformat,
 140                         packet->tag,
 141                         packet->length);
 142
 143         return 0;
 144 }
 145
 146 /**
 147  *      read_openpgp_stream - Reads a stream of OpenPGP packets.
 148  *      @getchar_func: The function to get the next character from the stream.
 149  *      @ctx: A pointer to the context structure for getchar_func.
 150  *      @packets: The outputted list of packets.
 151  *      @maxnum: The maximum number of keys to read. 0 means unlimited.
 152  *
 153  *      This function uses getchar_func to read characters from an OpenPGP
 154  *      packet stream and reads the packets into a linked list of packets
 155  *      ready for parsing as a public key or whatever.
 156  */
 157 int read_openpgp_stream(int (*getchar_func)(void *ctx, size_t count,
 158                                 unsigned char *c),
 159                                 void *ctx,
 160                                 struct openpgp_packet_list **packets,
 161                                 int maxnum)
 162 {
 163         unsigned char                    curchar = 0;
 164         struct openpgp_packet_list      *curpacket = NULL;
 165         int                              rc = 0;
 166         int                              keys = 0;
 167         bool                             inpacket = false;
 168
 169         assert(packets != NULL);
 170         curpacket = *packets;
 171         if (curpacket != NULL) {
 172                 while (curpacket->next != NULL) {
 173                         curpacket = curpacket->next;
 174                 }
 175         }
 176
 177         while (!rc && (maxnum == 0 || keys < maxnum) &&
 178                         !getchar_func(ctx, 1, &curchar)) {
 179                 if (!inpacket && (curchar & 0x80)) {
 180                         /*
 181                          * New packet. Record the fact we're in a packet and
 182                          * allocate memory for it.
 183                          */
 184                         inpacket = true;
 185                         if (curpacket != NULL) {
 186                                 curpacket->next = malloc(sizeof (*curpacket));
 187                                 curpacket = curpacket->next;
 188                         } else {
 189                                 *packets = curpacket =
 190                                         malloc(sizeof (*curpacket));
 191                         }
 192                         memset(curpacket, 0, sizeof(*curpacket));
 193                         curpacket->packet =
 194                                 malloc(sizeof (*curpacket->packet));
 195                         memset(curpacket->packet, 0,
 196                                         sizeof(*curpacket->packet));
 197
 198                         curpacket->packet->newformat = (curchar & 0x40);
 199
 200                         /*
 201                          * TODO: Better error checking on getchar_func.
 202                          */
 203                         if (curpacket->packet->newformat) {
 204                                 curpacket->packet->tag = (curchar & 0x3F);
 205                                 rc = getchar_func(ctx, 1, &curchar);
 206                                 curpacket->packet->length = curchar;
 207                                 if (curpacket->packet->length > 191 &&
 208                                         curpacket->packet->length < 224) {
 209                                         rc = getchar_func(ctx, 1, &curchar);
 210                                         curpacket->packet->length -= 192;
 211                                         curpacket->packet->length <<= 8;
 212                                         curpacket->packet->length += curchar;
 213                                         curpacket->packet->length += 192;
 214                                 } else if (curpacket->packet->length > 223 &&
 215                                         curpacket->packet->length < 255) {
 216                                         logthing(LOGTHING_NOTICE,
 217                                                 "Partial length;"
 218                                                 " not supported.");
 219                                 } else if (curpacket->packet->length == 255) {
 220                                         /*
 221                                          * 5 byte length; ie 255 followed by 3
 222                                          * bytes of MSB length.
 223                                          */
 224                                         rc = getchar_func(ctx, 1, &curchar);
 225                                         curpacket->packet->length = curchar;
 226                                         curpacket->packet->length <<= 8;
 227                                         rc = getchar_func(ctx, 1, &curchar);
 228                                         curpacket->packet->length = curchar;
 229                                         curpacket->packet->length <<= 8;
 230                                         rc = getchar_func(ctx, 1, &curchar);
 231                                         curpacket->packet->length = curchar;
 232                                         curpacket->packet->length <<= 8;
 233                                         rc = getchar_func(ctx, 1, &curchar);
 234                                         curpacket->packet->length = curchar;
 235                                 }
 236                         } else {
 237                                 curpacket->packet->tag = (curchar & 0x3C) >> 2;
 238                                 switch (curchar & 3) {
 239                                 case 0:
 240                                         rc = getchar_func(ctx, 1, &curchar);
 241                                         curpacket->packet->length = curchar;
 242                                         break;
 243                                 case 1:
 244                                         rc = getchar_func(ctx, 1, &curchar);
 245                                         curpacket->packet->length = curchar;
 246                                         curpacket->packet->length <<= 8;
 247                                         rc = getchar_func(ctx, 1, &curchar);
 248                                         curpacket->packet->length += curchar;
 249                                         break;
 250                                 case 2:
 251                                         rc = getchar_func(ctx, 1, &curchar);
 252                                         curpacket->packet->length =
 253                                                 (curchar << 24);
 254                                         rc = getchar_func(ctx, 1, &curchar);
 255                                         curpacket->packet->length +=
 256                                                 (curchar << 16);
 257                                         rc = getchar_func(ctx, 1, &curchar);
 258                                         curpacket->packet->length +=
 259                                                 (curchar << 8);
 260                                         rc = getchar_func(ctx, 1, &curchar);
 261                                         curpacket->packet->length += curchar;
 262                                         break;
 263                                 case 3:
 264                                         logthing(LOGTHING_ERROR,
 265                                                 "Unsupported length type 3.");
 266                                         curpacket->packet->length = 0;
 267                                         curpacket->packet->data = NULL;
 268                                         rc = -1;
 269                                         break;
 270                                 }
 271                         }
 272
 273                         if (rc == 0) {
 274                                 if (curpacket->packet->tag == 6) {
 275                                         keys++;
 276                                 }
 277                                 curpacket->packet->data =
 278                                         malloc(curpacket->packet->length *
 279                                         sizeof(unsigned char));
 280                                 if (curpacket->packet->data == NULL) {
 281                                         logthing(LOGTHING_ERROR,
 282                                                 "Can't allocate memory for "
 283                                                 "packet!");
 284                                         rc = -1;
 285                                 } else {
 286                                         rc = getchar_func(ctx,
 287                                                 curpacket->packet->length,
 288                                                 curpacket->packet->data);
 289                                 }
 290                         }
 291                         inpacket = false;
 292                 } else {
 293                         logthing(LOGTHING_ERROR, "Unexpected character: 0x%X",
 294                                 curchar);
 295                         rc = 1;
 296                 }
 297         }
 298
 299         return (rc);
 300 }
 301
 302 /**
 303  *      write_openpgp_stream - Reads a stream of OpenPGP packets.
 304  *      @putchar_func: The function to put the next character to the stream.
 305  *      @ctx: A pointer to the context structure for putchar_func.
 306  *      @packets: The list of packets.
 307  *
 308  *      This function uses putchar_func to write characters to an OpenPGP
 309  *      packet stream from a linked list of packets.
 310  */
 311 int write_openpgp_stream(int (*putchar_func)(void *ctx, size_t count,
 312                                                 unsigned char *c),
 313                                 void *ctx,
 314                                 struct openpgp_packet_list *packets)
 315 {
 316         unsigned char   curchar = 0;
 317
 318         while (packets != NULL) {
 319                 curchar = 0x80;
 320                 if (packets->packet->newformat) {
 321                         curchar |= 0x40;
 322                         curchar |= packets->packet->tag;
 323                         putchar_func(ctx, 1, &curchar);
 324
 325                         if (packets->packet->length < 192) {
 326                                 curchar = packets->packet->length;
 327                                 putchar_func(ctx, 1, &curchar);
 328                         } else if (packets->packet->length > 191 &&
 329                                 packets->packet->length < 8383) {
 330                                 curchar = (((packets->packet->length - 192) &
 331                                          0xFF00) >> 8) + 192;
 332                                 putchar_func(ctx, 1, &curchar);
 333
 334                                 curchar = (packets->packet->length - 192) &
 335                                          0xFF;
 336                                 putchar_func(ctx, 1, &curchar);
 337                         } else {
 338                                 logthing(LOGTHING_ERROR,
 339                                         "Unsupported new format length.");
 340                         }
 341                 } else {
 342                         curchar |= (packets->packet->tag << 2);
 343                         if (packets->packet->length < 256) {
 344                                 putchar_func(ctx, 1, &curchar);
 345                                 curchar = packets->packet->length;
 346                                 putchar_func(ctx, 1, &curchar);
 347                         } else if (packets->packet->length < 0x10000) {
 348                                 curchar |= 1;
 349                                 putchar_func(ctx, 1, &curchar);
 350                                 curchar = packets->packet->length >> 8;
 351                                 putchar_func(ctx, 1, &curchar);
 352                                 curchar = packets->packet->length & 0xFF;
 353                                 putchar_func(ctx, 1, &curchar);
 354                         } else {
 355                                 curchar |= 2;
 356                                 putchar_func(ctx, 1, &curchar);
 357                                 curchar = packets->packet->length >> 24;
 358                                 putchar_func(ctx, 1, &curchar);
 359                                 curchar = (packets->packet->length >> 16) & 0xFF;
 360                                 putchar_func(ctx, 1, &curchar);
 361                                 curchar = (packets->packet->length >> 8) & 0xFF;
 362                                 putchar_func(ctx, 1, &curchar);
 363                                 curchar = packets->packet->length & 0xFF;
 364                                 putchar_func(ctx, 1, &curchar);
 365                         }
 366                 }
 367
 368                 putchar_func(ctx, packets->packet->length,
 369                                 packets->packet->data);
 370                 packets = packets->next;
 371         }
 372         return 0;
 373 }
 374
 375 /**
 376  *      flatten_publickey - Convert a publickey to an OpenPGP packet list.
 377  *      @key: The public key.
 378  *      @packets: The outputted packet list.
 379  *
 380  *      This function converts public key structure to a linked list of OpenPGP
 381  *      packets ready for outputing or storage.
 382  */
 383 int flatten_publickey(struct openpgp_publickey *key,
 384                         struct openpgp_packet_list **packets,
 385                         struct openpgp_packet_list **list_end)
 386 {
 387         struct openpgp_signedpacket_list        *tmpsignedlist = NULL;
 388         struct openpgp_packet_list              *tmplist = NULL;
 389
 390         while (key != NULL) {
 391                 /*
 392                  * First write the public key packet out.
 393                  */
 394                 ADD_PACKET_TO_LIST((*list_end), packet_dup(key->publickey));
 395                 if (*packets == NULL) {
 396                         *packets = *list_end;
 397                 }
 398
 399                 /*
 400                  * Now do any revocation signatures on the main key.
 401                  */
 402                 for (tmplist = key->revocations; tmplist != NULL;
 403                                 tmplist = tmplist->next) {
 404                         ADD_PACKET_TO_LIST((*list_end),
 405                                         packet_dup(tmplist->packet));
 406                 }
 407
 408                 /*
 409                  * Output any UIDs along with their signatures.
 410                  */
 411                 for (tmpsignedlist = key->uids; tmpsignedlist != NULL;
 412                                 tmpsignedlist = tmpsignedlist->next) {
 413
 414                         ADD_PACKET_TO_LIST((*list_end),
 415                                 packet_dup(tmpsignedlist->packet));
 416                         for (tmplist = tmpsignedlist->sigs; tmplist != NULL;
 417                                         tmplist = tmplist->next) {
 418                                 ADD_PACKET_TO_LIST((*list_end),
 419                                         packet_dup(tmplist->packet));
 420                         }
 421                 }
 422
 423                 /*
 424                  * Output any subkeys along with their signatures.
 425                  */
 426                 for (tmpsignedlist = key->subkeys; tmpsignedlist != NULL;
 427                                 tmpsignedlist = tmpsignedlist->next) {
 428
 429                         ADD_PACKET_TO_LIST((*list_end),
 430                                 packet_dup(tmpsignedlist->packet));
 431                         for (tmplist = tmpsignedlist->sigs; tmplist != NULL;
 432                                         tmplist = tmplist->next) {
 433                                 ADD_PACKET_TO_LIST((*list_end),
 434                                         packet_dup(tmplist->packet));
 435                         }
 436                 }
 437                 key = key->next;
 438         }
 439         return 0;
 440 }