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