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