decodekey.c

   1 /*
   2  * decodekey.c - Routines to further decode an OpenPGP key.
   3  *
   4  * Jonathan McDowell <noodles@earth.li>
   5  *
   6  * Copyright 2002 Project Purple
   7  *
   8  * $Id: decodekey.c,v 1.4 2003/09/28 21:07:50 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 #include <time.h>
  17
  18 #include "decodekey.h"
  19 #include "hash.h"
  20 #include "keyid.h"
  21 #include "keystructs.h"
  22 #include "ll.h"
  23 #include "log.h"
  24
  25 /*
  26  *      parse_subpackets - Parse the subpackets of a Type 4 signature.
  27  *      @data: The subpacket data.
  28  *      @keyid: A pointer to where we should return the keyid.
  29  *
  30  *      This function parses the subkey data of a Type 4 signature and fills
  31  *      in the supplied variables. It also returns the length of the data
  32  *      processed.
  33  */
  34 int parse_subpackets(unsigned char *data, uint64_t *keyid)
  35 {
  36         int offset = 0;
  37         int length = 0;
  38         int packetlen = 0;
  39
  40         assert(data != NULL);
  41
  42         length = (data[0] << 8) + data[1] + 2;
  43
  44         offset = 2;
  45         while (offset < length) {
  46                 packetlen = data[offset++];
  47                 if (packetlen > 191 && packetlen < 255) {
  48                         packetlen = ((packetlen - 192) << 8) +
  49                                         data[offset++] + 192;
  50                 } else if (packetlen == 255) {
  51                         packetlen = data[offset++];
  52                         packetlen <<= 8;
  53                         packetlen = data[offset++];
  54                         packetlen <<= 8;
  55                         packetlen = data[offset++];
  56                         packetlen <<= 8;
  57                         packetlen = data[offset++];
  58                 }
  59                 switch (data[offset] & 0x7F) {
  60                 case 2:
  61                         /*
  62                          * Signature creation time. Might want to output this?
  63                          */
  64                         break;
  65                 case 3:
  66                         /*
  67                          * Signature expiration time. Might want to output this?
  68                          */
  69                         break;
  70                 case 16:
  71                         *keyid = data[offset+packetlen - 8];
  72                         *keyid <<= 8;
  73                         *keyid += data[offset+packetlen - 7];
  74                         *keyid <<= 8;
  75                         *keyid += data[offset+packetlen - 6];
  76                         *keyid <<= 8;
  77                         *keyid += data[offset+packetlen - 5];
  78                         *keyid <<= 8;
  79                         *keyid += data[offset+packetlen - 4];
  80                         *keyid <<= 8;
  81                         *keyid += data[offset+packetlen - 3];
  82                         *keyid <<= 8;
  83                         *keyid += data[offset+packetlen - 2];
  84                         *keyid <<= 8;
  85                         *keyid += data[offset+packetlen - 1];
  86                         break;
  87                 case 23:
  88                         /*
  89                          * Key server preferences. Including no-modify.
  90                          */
  91                         break;
  92                 case 25:
  93                         /*
  94                          * Primary UID.
  95                          */
  96                         break;
  97                 default:
  98                         /*
  99                          * We don't care about unrecognized packets unless bit
 100                          * 7 is set in which case we log a major error.
 101                          */
 102                         if (data[offset] & 0x80) {
 103                                 logthing(LOGTHING_CRITICAL,
 104                                 "Critical subpacket type not parsed: 0x%X",
 105                                         data[offset]);
 106                         }
 107
 108                 }
 109                 offset += packetlen;
 110         }
 111
 112         return length;
 113 }
 114
 115 /**
 116  *      keysigs - Return the sigs on a given OpenPGP signature list.
 117  *      @curll: The current linked list. Can be NULL to create a new list.
 118  *      @sigs: The signature list we want the sigs on.
 119  *
 120  *      Returns a linked list of stats_key elements containing the sigs on the
 121  *      supplied OpenPGP packet list.
 122  */
 123 struct ll *keysigs(struct ll *curll,
 124                 struct openpgp_packet_list *sigs)
 125 {
 126         uint64_t keyid = 0;
 127
 128         while (sigs != NULL) {
 129                 keyid = sig_keyid(sigs->packet);
 130                 sigs = sigs->next;
 131                 curll = lladd(curll, createandaddtohash(keyid));
 132         }
 133
 134         return curll;
 135 }
 136
 137 /**
 138  *      sig_keyid - Return the keyid for a given OpenPGP signature packet.
 139  *      @packet: The signature packet.
 140  *
 141  *      Returns the keyid for the supplied signature packet.
 142  */
 143 uint64_t sig_keyid(struct openpgp_packet *packet)
 144 {
 145         int length = 0;
 146         uint64_t keyid = 0;
 147
 148         if (packet != NULL) {
 149                 keyid = 0;
 150                 switch (packet->data[0]) {
 151                 case 2:
 152                 case 3:
 153                         keyid = packet->data[7];
 154                         keyid <<= 8;
 155                         keyid += packet->data[8];
 156                         keyid <<= 8;
 157                         keyid += packet->data[9];
 158                         keyid <<= 8;
 159                         keyid += packet->data[10];
 160                         keyid <<= 8;
 161                         keyid += packet->data[11];
 162                         keyid <<= 8;
 163                         keyid += packet->data[12];
 164                         keyid <<= 8;
 165                         keyid += packet->data[13];
 166                         keyid <<= 8;
 167                         keyid += packet->data[14];
 168                         break;
 169                 case 4:
 170                         length = parse_subpackets(&packet->data[4],
 171                                         &keyid);
 172                         parse_subpackets(&packet->data[length + 4],
 173                                         &keyid);
 174                         /*
 175                          * Don't bother to look at the unsigned packets.
 176                          */
 177                         break;
 178                 default:
 179                         break;
 180                 }
 181         }
 182
 183         return keyid;
 184 }
 185
 186 /*
 187  * TODO: Abstract out; all our linked lists should be generic and then we can
 188  * llsize them.
 189  */
 190 int spsize(struct openpgp_signedpacket_list *list)
 191 {
 192         int size = 0;
 193         struct openpgp_signedpacket_list *cur;
 194
 195         for (cur = list; cur != NULL; cur = cur->next, size++) ;
 196
 197         return size;
 198 }
 199
 200 /**
 201  *      keyuids - Takes a key and returns an array of its UIDs
 202  *      @key: The key to get the uids of.
 203  *      @primary: A pointer to store the primary UID in.
 204  *
 205  *      keyuids takes a public key structure and builds an array of the UIDs
 206  *      on the key. It also attempts to work out the primary UID and returns a
 207  *      separate pointer to that particular element of the array.
 208  */
 209 char **keyuids(struct openpgp_publickey *key, char **primary)
 210 {
 211         struct openpgp_signedpacket_list *curuid = NULL;
 212         char buf[1024];
 213         char **uids = NULL;
 214         int count = 0;
 215
 216         *primary = NULL;
 217         if (key != NULL && key->uids != NULL) {
 218                 uids = malloc((spsize(key->uids) + 1) * sizeof (char *));
 219
 220                 curuid = key->uids;
 221                 while (curuid != NULL) {
 222                         buf[0] = 0;
 223                         if (curuid->packet->tag == 13) {
 224                                 snprintf(buf, 1023, "%.*s",
 225                                                 (int) curuid->packet->length,
 226                                                 curuid->packet->data);
 227                                 uids[count++] = strdup(buf);
 228                         }
 229                         curuid = curuid -> next;
 230                 }
 231                 uids[count] = NULL;
 232
 233                 /*
 234                  * TODO: Parse subpackets for real primary ID (v4 keys)
 235                  */
 236                 if (primary != NULL) {
 237                         *primary = uids[0];
 238                 }
 239         }
 240
 241         return uids;
 242 }