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 1.5 2004/03/23 12:35:11 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 20:
  88                         /*
  89                          * Annotation data.
  90                          */
  91                         break;
  92
  93                 case 23:
  94                         /*
  95                          * Key server preferences. Including no-modify.
  96                          */
  97                         break;
  98                 case 25:
  99                         /*
 100                          * Primary UID.
 101                          */
 102                         break;
 103                 default:
 104                         /*
 105                          * We don't care about unrecognized packets unless bit
 106                          * 7 is set in which case we log a major error.
 107                          */
 108                         if (data[offset] & 0x80) {
 109                                 logthing(LOGTHING_CRITICAL,
 110                                 "Critical subpacket type not parsed: 0x%X",
 111                                         data[offset]);
 112                         }
 113
 114                 }
 115                 offset += packetlen;
 116         }
 117
 118         return length;
 119 }
 120
 121 /**
 122  *      keysigs - Return the sigs on a given OpenPGP signature list.
 123  *      @curll: The current linked list. Can be NULL to create a new list.
 124  *      @sigs: The signature list we want the sigs on.
 125  *
 126  *      Returns a linked list of stats_key elements containing the sigs on the
 127  *      supplied OpenPGP packet list.
 128  */
 129 struct ll *keysigs(struct ll *curll,
 130                 struct openpgp_packet_list *sigs)
 131 {
 132         uint64_t keyid = 0;
 133
 134         while (sigs != NULL) {
 135                 keyid = sig_keyid(sigs->packet);
 136                 sigs = sigs->next;
 137                 curll = lladd(curll, createandaddtohash(keyid));
 138         }
 139
 140         return curll;
 141 }
 142
 143 /**
 144  *      sig_keyid - Return the keyid for a given OpenPGP signature packet.
 145  *      @packet: The signature packet.
 146  *
 147  *      Returns the keyid for the supplied signature packet.
 148  */
 149 uint64_t sig_keyid(struct openpgp_packet *packet)
 150 {
 151         int length = 0;
 152         uint64_t keyid = 0;
 153
 154         if (packet != NULL) {
 155                 keyid = 0;
 156                 switch (packet->data[0]) {
 157                 case 2:
 158                 case 3:
 159                         keyid = packet->data[7];
 160                         keyid <<= 8;
 161                         keyid += packet->data[8];
 162                         keyid <<= 8;
 163                         keyid += packet->data[9];
 164                         keyid <<= 8;
 165                         keyid += packet->data[10];
 166                         keyid <<= 8;
 167                         keyid += packet->data[11];
 168                         keyid <<= 8;
 169                         keyid += packet->data[12];
 170                         keyid <<= 8;
 171                         keyid += packet->data[13];
 172                         keyid <<= 8;
 173                         keyid += packet->data[14];
 174                         break;
 175                 case 4:
 176                         length = parse_subpackets(&packet->data[4],
 177                                         &keyid);
 178                         parse_subpackets(&packet->data[length + 4],
 179                                         &keyid);
 180                         /*
 181                          * Don't bother to look at the unsigned packets.
 182                          */
 183                         break;
 184                 default:
 185                         break;
 186                 }
 187         }
 188
 189         return keyid;
 190 }
 191
 192 /*
 193  * TODO: Abstract out; all our linked lists should be generic and then we can
 194  * llsize them.
 195  */
 196 int spsize(struct openpgp_signedpacket_list *list)
 197 {
 198         int size = 0;
 199         struct openpgp_signedpacket_list *cur;
 200
 201         for (cur = list; cur != NULL; cur = cur->next, size++) ;
 202
 203         return size;
 204 }
 205
 206 /**
 207  *      keyuids - Takes a key and returns an array of its UIDs
 208  *      @key: The key to get the uids of.
 209  *      @primary: A pointer to store the primary UID in.
 210  *
 211  *      keyuids takes a public key structure and builds an array of the UIDs
 212  *      on the key. It also attempts to work out the primary UID and returns a
 213  *      separate pointer to that particular element of the array.
 214  */
 215 char **keyuids(struct openpgp_publickey *key, char **primary)
 216 {
 217         struct openpgp_signedpacket_list *curuid = NULL;
 218         char buf[1024];
 219         char **uids = NULL;
 220         int count = 0;
 221
 222         *primary = NULL;
 223         if (key != NULL && key->uids != NULL) {
 224                 uids = malloc((spsize(key->uids) + 1) * sizeof (char *));
 225
 226                 curuid = key->uids;
 227                 while (curuid != NULL) {
 228                         buf[0] = 0;
 229                         if (curuid->packet->tag == 13) {
 230                                 snprintf(buf, 1023, "%.*s",
 231                                                 (int) curuid->packet->length,
 232                                                 curuid->packet->data);
 233                                 uids[count++] = strdup(buf);
 234                         }
 235                         curuid = curuid -> next;
 236                 }
 237                 uids[count] = NULL;
 238
 239                 /*
 240                  * TODO: Parse subpackets for real primary ID (v4 keys)
 241                  */
 242                 if (primary != NULL) {
 243                         *primary = uids[0];
 244                 }
 245         }
 246
 247         return uids;
 248 }