decodekey.c

   1 /*
   2  * decodekey.c - Routines to further decode an OpenPGP key.
   3  *
   4  * Copyright 2002-2008 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, see <https://www.gnu.org/licenses/>.
  17  */
  18
  19 #include <assert.h>
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <time.h>
  24
  25 #include "decodekey.h"
  26 #include "hash.h"
  27 #include "keyid.h"
  28 #include "keystructs.h"
  29 #include "ll.h"
  30 #include "openpgp.h"
  31
  32 /*
  33  *      parse_subpackets - Parse the subpackets of a Type 4 signature.
  34  *      @data: The subpacket data.
  35  *      @len: The amount of data available to read.
  36  *      @parselen: The amount of data that was actually parsed.
  37  *      @keyid: A pointer to where we should return the keyid.
  38  *      @creationtime: A pointer to where we should return the creation time.
  39  *
  40  *      This function parses the subkey data of a Type 4 signature and fills
  41  *      in the supplied variables. It also returns the length of the data
  42  *      processed. If the value of any piece of data is not desired a NULL
  43  *      can be passed instead of a pointer to a storage area for that value.
  44  */
  45 onak_status_t parse_subpackets(unsigned char *data, size_t len,
  46                 size_t *parselen, uint64_t *keyid, time_t *creation)
  47 {
  48         int offset = 0;
  49         int length = 0;
  50         int packetlen = 0;
  51
  52         assert(data != NULL);
  53
  54         /* Make sure we actually have the 2 byte length field */
  55         if (len < 2) {
  56                 return ONAK_E_INVALID_PKT;
  57         }
  58
  59         length = (data[0] << 8) + data[1] + 2;
  60
  61         /* If the length is off the end of the data available, it's bogus */
  62         if (len < length) {
  63                 return ONAK_E_INVALID_PKT;
  64         }
  65
  66         *parselen = length;
  67
  68         offset = 2;
  69         while (offset < length) {
  70                 packetlen = data[offset++];
  71                 if (packetlen > 191 && packetlen < 255) {
  72                         packetlen = ((packetlen - 192) << 8) +
  73                                         data[offset++] + 192;
  74                 } else if (packetlen == 255) {
  75                         packetlen = data[offset++];
  76                         packetlen <<= 8;
  77                         packetlen |= data[offset++];
  78                         packetlen <<= 8;
  79                         packetlen |= data[offset++];
  80                         packetlen <<= 8;
  81                         packetlen |= data[offset++];
  82                 }
  83                 /* Check the supplied length is within the remaining data */
  84                 if (packetlen == 0 || (packetlen + offset) > length) {
  85                         return ONAK_E_INVALID_PKT;
  86                 }
  87                 switch (data[offset] & 0x7F) {
  88                 case OPENPGP_SIGSUB_CREATION:
  89                         /*
  90                          * Signature creation time.
  91                          */
  92                         if (creation != NULL) {
  93                                 *creation = data[offset + packetlen - 4];
  94                                 *creation <<= 8;
  95                                 *creation = data[offset + packetlen - 3];
  96                                 *creation <<= 8;
  97                                 *creation = data[offset + packetlen - 2];
  98                                 *creation <<= 8;
  99                                 *creation = data[offset + packetlen - 1];
 100                         }
 101                         break;
 102                         /*
 103                          * Signature expiration time. Might want to output this?
 104                          */
 105                         break;
 106                 case OPENPGP_SIGSUB_ISSUER:
 107                         if (keyid != NULL) {
 108                                 *keyid = data[offset+packetlen - 8];
 109                                 *keyid <<= 8;
 110                                 *keyid += data[offset+packetlen - 7];
 111                                 *keyid <<= 8;
 112                                 *keyid += data[offset+packetlen - 6];
 113                                 *keyid <<= 8;
 114                                 *keyid += data[offset+packetlen - 5];
 115                                 *keyid <<= 8;
 116                                 *keyid += data[offset+packetlen - 4];
 117                                 *keyid <<= 8;
 118                                 *keyid += data[offset+packetlen - 3];
 119                                 *keyid <<= 8;
 120                                 *keyid += data[offset+packetlen - 2];
 121                                 *keyid <<= 8;
 122                                 *keyid += data[offset+packetlen - 1];
 123                         }
 124                         break;
 125                 case OPENPGP_SIGSUB_EXPIRY:
 126                 case OPENPGP_SIGSUB_EXPORTABLE:
 127                 case OPENPGP_SIGSUB_TRUSTSIG:
 128                 case OPENPGP_SIGSUB_REGEX:
 129                 case OPENPGP_SIGSUB_REVOCABLE:
 130                 case OPENPGP_SIGSUB_CAPABILITIES:
 131                 case OPENPGP_SIGSUB_KEYEXPIRY:
 132                 case OPENPGP_SIGSUB_ARR:
 133                 case OPENPGP_SIGSUB_PREFSYM:
 134                 case OPENPGP_SIGSUB_REVOCATION_KEY:
 135                 case OPENPGP_SIGSUB_ISSUER_UID:
 136                 case OPENPGP_SIGSUB_URL:
 137                 case OPENPGP_SIGSUB_ISSUER_FINGER:
 138                 case OPENPGP_SIGSUB_NOTATION:
 139                 case OPENPGP_SIGSUB_PREFHASH:
 140                 case OPENPGP_SIGSUB_PREFCOMPRESS:
 141                 case OPENPGP_SIGSUB_KEYSERVER:
 142                 case OPENPGP_SIGSUB_PREFKEYSERVER:
 143                 case OPENPGP_SIGSUB_PRIMARYUID:
 144                 case OPENPGP_SIGSUB_POLICYURI:
 145                 case OPENPGP_SIGSUB_KEYFLAGS:
 146                 case OPENPGP_SIGSUB_SIGNER_UID:
 147                 case OPENPGP_SIGSUB_REVOKE_REASON:
 148                 case OPENPGP_SIGSUB_FEATURES:
 149                 case OPENPGP_SIGSUB_SIGNATURE_TARGET:
 150                 case OPENPGP_SIGSUB_EMBEDDED_SIG:
 151                         /*
 152                          * Various subpacket types we know about, but don't
 153                          * currently handle. Some are candidates for being
 154                          * supported if we add signature checking support.
 155                          */
 156                         break;
 157                 default:
 158                         /*
 159                          * We don't care about unrecognized packets unless bit
 160                          * 7 is set in which case we log a major error.
 161                          */
 162                         if (data[offset] & 0x80) {
 163                                 return ONAK_E_UNSUPPORTED_FEATURE;
 164                         }
 165                 }
 166                 offset += packetlen;
 167         }
 168
 169         return ONAK_E_OK;
 170 }
 171
 172 /**
 173  *      sig_info - Get info on a given OpenPGP signature packet
 174  *      @packet: The signature packet
 175  *      @keyid: A pointer for where to return the signature keyid
 176  *      @creation: A pointer for where to return the signature creation time
 177  *
 178  *      Gets any info about a signature packet; parses the subpackets for a v4
 179  *      key or pulls the data directly from v2/3. NULL can be passed for any
 180  *      values which aren't cared about.
 181  */
 182 onak_status_t sig_info(struct openpgp_packet *packet, uint64_t *keyid,
 183                 time_t *creation)
 184 {
 185         size_t length = 0;
 186         onak_status_t res;
 187
 188         if (packet != NULL) {
 189                 switch (packet->data[0]) {
 190                 case 2:
 191                 case 3:
 192                         if (keyid != NULL) {
 193                                 *keyid = packet->data[7];
 194                                 *keyid <<= 8;
 195                                 *keyid += packet->data[8];
 196                                 *keyid <<= 8;
 197                                 *keyid += packet->data[9];
 198                                 *keyid <<= 8;
 199                                 *keyid += packet->data[10];
 200                                 *keyid <<= 8;
 201                                 *keyid += packet->data[11];
 202                                 *keyid <<= 8;
 203                                 *keyid += packet->data[12];
 204                                 *keyid <<= 8;
 205                                 *keyid += packet->data[13];
 206                                 *keyid <<= 8;
 207                                 *keyid += packet->data[14];
 208                         }
 209                         if (creation != NULL) {
 210                                 *creation = packet->data[3];
 211                                 *creation <<= 8;
 212                                 *creation = packet->data[4];
 213                                 *creation <<= 8;
 214                                 *creation = packet->data[5];
 215                                 *creation <<= 8;
 216                                 *creation = packet->data[6];
 217                         }
 218                         break;
 219                 case 4:
 220                         res = parse_subpackets(&packet->data[4],
 221                                         packet->length - 4,
 222                                         &length, keyid, creation);
 223                         if (res != ONAK_E_OK) {
 224                                 return res;
 225                         }
 226                         res = parse_subpackets(&packet->data[length + 4],
 227                                         packet->length - (4 + length),
 228                                         &length, keyid, creation);
 229                         if (res != ONAK_E_OK) {
 230                                 return res;
 231                         }
 232                         break;
 233                 default:
 234                         break;
 235                 }
 236         }
 237
 238         return ONAK_E_OK;
 239 }
 240
 241 /**
 242  *      sig_keyid - Return the keyid for a given OpenPGP signature packet.
 243  *      @packet: The signature packet.
 244  *
 245  *      Returns the keyid for the supplied signature packet.
 246  */
 247 uint64_t sig_keyid(struct openpgp_packet *packet)
 248 {
 249         uint64_t keyid = 0;
 250
 251         sig_info(packet, &keyid, NULL);
 252
 253         return keyid;
 254 }
 255
 256
 257 /*
 258  * TODO: Abstract out; all our linked lists should be generic and then we can
 259  * llsize them.
 260  */
 261 int spsize(struct openpgp_signedpacket_list *list)
 262 {
 263         int size = 0;
 264         struct openpgp_signedpacket_list *cur;
 265
 266         for (cur = list; cur != NULL; cur = cur->next, size++) ;
 267
 268         return size;
 269 }
 270
 271 /**
 272  *      keyuids - Takes a key and returns an array of its UIDs
 273  *      @key: The key to get the uids of.
 274  *      @primary: A pointer to store the primary UID in.
 275  *
 276  *      keyuids takes a public key structure and builds an array of the UIDs
 277  *      on the key. It also attempts to work out the primary UID and returns a
 278  *      separate pointer to that particular element of the array.
 279  */
 280 char **keyuids(struct openpgp_publickey *key, char **primary)
 281 {
 282         struct openpgp_signedpacket_list *curuid = NULL;
 283         char buf[1024];
 284         char **uids = NULL;
 285         int count = 0;
 286
 287         if (primary != NULL) {
 288                 *primary = NULL;
 289         }
 290
 291         if (key != NULL && key->uids != NULL) {
 292                 uids = malloc((spsize(key->uids) + 1) * sizeof (char *));
 293
 294                 curuid = key->uids;
 295                 while (curuid != NULL) {
 296                         buf[0] = 0;
 297                         if (curuid->packet->tag == OPENPGP_PACKET_UID) {
 298                                 snprintf(buf, 1023, "%.*s",
 299                                                 (int) curuid->packet->length,
 300                                                 curuid->packet->data);
 301                                 uids[count++] = strdup(buf);
 302                         }
 303                         curuid = curuid -> next;
 304                 }
 305                 uids[count] = NULL;
 306
 307                 /*
 308                  * TODO: Parse subpackets for real primary ID (v4 keys)
 309                  */
 310                 if (primary != NULL) {
 311                         *primary = uids[0];
 312                 }
 313         }
 314
 315         return uids;
 316 }
 317
 318 /**
 319  *      keysubkeys - Takes a key and returns an array of its subkey keyids.
 320  *      @key: The key to get the subkeys of.
 321  *
 322  *      keysubkeys takes a public key structure and returns an array of the
 323  *      subkey keyids for that key.
 324  */
 325 struct openpgp_fingerprint *keysubkeys(struct openpgp_publickey *key)
 326 {
 327         struct openpgp_signedpacket_list *cursubkey = NULL;
 328         struct openpgp_fingerprint       *subkeys = NULL;
 329         int                               count = 0;
 330
 331         if (key != NULL && key->subkeys != NULL) {
 332                 subkeys = malloc((spsize(key->subkeys) + 1) *
 333                                 sizeof (struct openpgp_fingerprint));
 334                 cursubkey = key->subkeys;
 335                 while (cursubkey != NULL) {
 336                         get_fingerprint(cursubkey->packet, &subkeys[count++]);
 337                         cursubkey = cursubkey -> next;
 338                 }
 339                 subkeys[count].length = 0;
 340         }
 341
 342         return subkeys;
 343 }