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
   9 #include <assert.h>
  10 #include <stdbool.h>
  11 #include <stdio.h>
  12 #include <stdlib.h>
  13 #include <string.h>
  14 #include <time.h>
  15
  16 #include "decodekey.h"
  17 #include "hash.h"
  18 #include "keyid.h"
  19 #include "keystructs.h"
  20 #include "ll.h"
  21
  22 /*
  23  *      parse_subpackets - Parse the subpackets of a Type 4 signature.
  24  *      @data: The subpacket data.
  25  *      @keyid: A pointer to where we should return the keyid.
  26  *
  27  *      This function parses the subkey data of a Type 4 signature and fills
  28  *      in the supplied variables. It also returns the length of the data
  29  *      processed.
  30  */
  31 int parse_subpackets(unsigned char *data, uint64_t *keyid)
  32 {
  33         int offset = 0;
  34         int length = 0;
  35         int packetlen = 0;
  36
  37         assert(data != NULL);
  38
  39         length = (data[0] << 8) + data[1] + 2;
  40
  41         offset = 2;
  42         while (offset < length) {
  43                 packetlen = data[offset++];
  44                 if (packetlen > 191 && packetlen < 255) {
  45                         packetlen = ((packetlen - 192) << 8) +
  46                                         data[offset++] + 192;
  47                 } else if (packetlen == 255) {
  48                         packetlen = data[offset++];
  49                         packetlen <<= 8;
  50                         packetlen = data[offset++];
  51                         packetlen <<= 8;
  52                         packetlen = data[offset++];
  53                         packetlen <<= 8;
  54                         packetlen = data[offset++];
  55                 }
  56                 switch (data[offset]) {
  57                 case 2:
  58                         /*
  59                          * Signature creation time. Might want to output this?
  60                          */
  61                         break;
  62                 case 0x83:
  63                         /*
  64                          * Signature expiration time. Might want to output this?
  65                          */
  66                         break;
  67                 case 16:
  68                         *keyid = data[offset+packetlen - 8];
  69                         *keyid <<= 8;
  70                         *keyid += data[offset+packetlen - 7];
  71                         *keyid <<= 8;
  72                         *keyid += data[offset+packetlen - 6];
  73                         *keyid <<= 8;
  74                         *keyid += data[offset+packetlen - 5];
  75                         *keyid <<= 8;
  76                         *keyid += data[offset+packetlen - 4];
  77                         *keyid <<= 8;
  78                         *keyid += data[offset+packetlen - 3];
  79                         *keyid <<= 8;
  80                         *keyid += data[offset+packetlen - 2];
  81                         *keyid <<= 8;
  82                         *keyid += data[offset+packetlen - 1];
  83                         break;
  84                 case 23:
  85                         /*
  86                          * Key server preferences. Including no-modify.
  87                          */
  88                         break;
  89                 case 25:
  90                         /*
  91                          * Primary UID.
  92                          */
  93                         break;
  94                 default:
  95                         /*
  96                          * We don't care about unrecognized packets unless bit
  97                          * 7 is set in which case we prefer an error than
  98                          * ignoring it.
  99                          */
 100                         assert(!(data[offset] & 0x80));
 101                 }
 102                 offset += packetlen;
 103         }
 104
 105         return length;
 106 }
 107
 108 /**
 109  *      keysigs - Return the sigs on a given OpenPGP signature list.
 110  *      @curll: The current linked list. Can be NULL to create a new list.
 111  *      @sigs: The signature list we want the sigs on.
 112  *
 113  *      Returns a linked list of stats_key elements containing the sigs on the
 114  *      supplied OpenPGP packet list.
 115  */
 116 struct ll *keysigs(struct ll *curll,
 117                 struct openpgp_packet_list *sigs)
 118 {
 119         uint64_t keyid = 0;
 120
 121         while (sigs != NULL) {
 122                 keyid = sig_keyid(sigs->packet);
 123                 sigs = sigs->next;
 124                 curll = lladd(curll, createandaddtohash(keyid));
 125         }
 126
 127         return curll;
 128 }
 129
 130 /**
 131  *      sig_keyid - Return the keyid for a given OpenPGP signature packet.
 132  *      @packet: The signature packet.
 133  *
 134  *      Returns the keyid for the supplied signature packet.
 135  */
 136 uint64_t sig_keyid(struct openpgp_packet *packet)
 137 {
 138         int length = 0;
 139         uint64_t keyid = 0;
 140
 141         if (packet != NULL) {
 142                 keyid = 0;
 143                 switch (packet->data[0]) {
 144                 case 2:
 145                 case 3:
 146                         keyid = packet->data[7];
 147                         keyid <<= 8;
 148                         keyid += packet->data[8];
 149                         keyid <<= 8;
 150                         keyid += packet->data[9];
 151                         keyid <<= 8;
 152                         keyid += packet->data[10];
 153                         keyid <<= 8;
 154                         keyid += packet->data[11];
 155                         keyid <<= 8;
 156                         keyid += packet->data[12];
 157                         keyid <<= 8;
 158                         keyid += packet->data[13];
 159                         keyid <<= 8;
 160                         keyid += packet->data[14];
 161                         break;
 162                 case 4:
 163                         length = parse_subpackets(&packet->data[4],
 164                                         &keyid);
 165                         parse_subpackets(&packet->data[length + 4],
 166                                         &keyid);
 167                         /*
 168                          * Don't bother to look at the unsigned packets.
 169                          */
 170                         break;
 171                 default:
 172                         break;
 173                 }
 174         }
 175
 176         return keyid;
 177 }
 178
 179 /*
 180  * TODO: Abstract out; all our linked lists should be generic and then we can
 181  * llsize them.
 182  */
 183 int spsize(struct openpgp_signedpacket_list *list)
 184 {
 185         int size = 0;
 186         struct openpgp_signedpacket_list *cur;
 187
 188         for (cur = list; cur != NULL; cur = cur->next, size++) ;
 189
 190         return size;
 191 }
 192
 193 /**
 194  *      keyuids - Takes a key and returns an array of its UIDs
 195  *      @key: The key to get the uids of.
 196  *      @primary: A pointer to store the primary UID in.
 197  *
 198  *      keyuids takes a public key structure and builds an array of the UIDs
 199  *      on the key. It also attempts to work out the primary UID and returns a
 200  *      separate pointer to that particular element of the array.
 201  */
 202 char **keyuids(struct openpgp_publickey *key, char **primary)
 203 {
 204         struct openpgp_signedpacket_list *curuid = NULL;
 205         char buf[1024];
 206         char **uids = NULL;
 207         int count = 0;
 208
 209         if (key != NULL && key->uids != NULL) {
 210                 uids = malloc((spsize(key->uids) + 1) * sizeof (char *));
 211
 212                 curuid = key->uids;
 213                 while (curuid != NULL) {
 214                         buf[0] = 0;
 215                         if (curuid->packet->tag == 13) {
 216                                 snprintf(buf, 1023, "%.*s",
 217                                                 (int) curuid->packet->length,
 218                                                 curuid->packet->data);
 219                                 uids[count++] = strdup(buf);
 220                         }
 221                         curuid = curuid -> next;
 222                 }
 223                 uids[count] = NULL;
 224         }
 225         /*
 226          * TODO: Parse subpackets for real primary ID (v4 keys)
 227          */
 228         if (primary != NULL) {
 229                 *primary = uids[0];
 230         }
 231
 232         return uids;
 233 }