git.distorted.org.uk Git - u/mdw/catacomb/blob - key/key-misc.c

   1 /* -*-c-*-
   2  *
   3  * Simple key management
   4  *
   5  * (c) 1999 Straylight/Edgeware
   6  */
   7
   8 /*----- Licensing notice --------------------------------------------------*
   9  *
  10  * This file is part of Catacomb.
  11  *
  12  * Catacomb is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU Library General Public License as
  14  * published by the Free Software Foundation; either version 2 of the
  15  * License, or (at your option) any later version.
  16  *
  17  * Catacomb is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU Library General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU Library General Public
  23  * License along with Catacomb; if not, write to the Free
  24  * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
  25  * MA 02111-1307, USA.
  26  */
  27
  28 /*----- Header files ------------------------------------------------------*/
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32 #include <string.h>
  33 #include <time.h>
  34
  35 #include <mLib/bits.h>
  36 #include <mLib/hash.h>
  37 #include <mLib/sub.h>
  38 #include <mLib/sym.h>
  39
  40 #include "key.h"
  41
  42 /*----- Useful macros -----------------------------------------------------*/
  43
  44 #define KEY_WRITE(f) do {                                               \
  45      if (!(f)->f & KF_WRITE)                                            \
  46        return (KERR_READONLY);                                          \
  47    } while (0)
  48
  49 #define KEY_MODIFY(f) do { (f)->f |= KF_MODIFIED; } while (0)
  50
  51 #define KEY_LOAD(n) ((n) * 2)
  52
  53 /*----- Iteration and iterators -------------------------------------------*/
  54
  55 /* --- @key_mkiter@ --- *
  56  *
  57  * Arguments:   @key_iter *i@ = pointer to iterator object
  58  *              @key_file *f@ = pointer to file structure
  59  *
  60  * Returns:     ---
  61  *
  62  * Use:         Initializes a key iterator.  The keys are returned by
  63  *              @key_next@.
  64  */
  65
  66 void key_mkiter(key_iter *i, key_file *f)
  67 {
  68   HASH_MKITER(&i->i, &f->byid);
  69   i->t = time(0);
  70 }
  71
  72 /* --- @key_next@ --- *
  73  *
  74  * Arguments:   @key_iter *i@ = pointer to iterator object
  75  *
  76  * Returns:     Pointer to next key, or null.
  77  *
  78  * Use:         Returns the next key in some arbitrary sequence.
  79  */
  80
  81 key *key_next(key_iter *i)
  82 {
  83   hash_base *b;
  84   key *k;
  85   do {
  86     HASH_NEXT(&i->i, b);
  87     k = (key *)b;
  88   } while (k && KEY_EXPIRED(i->t, k->exp) && KEY_EXPIRED(i->t, k->del));
  89   return (k);
  90 }
  91
  92 /*----- Lookup ------------------------------------------------------------*/
  93
  94 /* --- @key_bytype@ --- *
  95  *
  96  * Arguments:   @key_file *f@ = key file we want a key from
  97  *              @const char *type@ = type string for desired key
  98  *
  99  * Returns:     Pointer to the best key to use, or null.
 100  *
 101  * Use:         Looks up a key by its type.  Returns the key with the latest
 102  *              expiry time.  This function will not return an expired key.
 103  */
 104
 105 key *key_bytype(key_file *f, const char *type)
 106 {
 107   time_t now = time(0);
 108   key *k;
 109   key_ref *kr;
 110
 111   if ((kr = sym_find(&f->bytype, type, -1, 0, 0)) == 0)
 112     return (0);
 113   for (k = kr->k; k && KEY_EXPIRED(now, k->exp); k = k->next)
 114     ;
 115   return (k);
 116 }
 117
 118 /* --- @key_byid@ --- *
 119  *
 120  * Arguments:   @key_file *f@ = key file to find a key from
 121  *              @uint32 id@ = id to look for
 122  *
 123  * Returns:     Key with matching id.
 124  *
 125  * Use:         Returns a key given its id.  This function will return an
 126  *              expired key, but not a deleted one.
 127  */
 128
 129 key *key_byid(key_file *f, uint32 id)
 130 {
 131   time_t t = time(0);
 132   hash_base **bin, *b;
 133
 134   bin = HASH_BIN(&f->byid, id);
 135   for (b = *bin; b; b = b->next) {
 136     if (b->hash == id) {
 137       key *k = (key *)b;
 138       if (KEY_EXPIRED(t, k->exp) && KEY_EXPIRED(t, k->del))
 139         return (0);
 140       return (k);
 141     }
 142   }
 143   return (0);
 144 }
 145
 146 /* --- @key_bytag@ --- *
 147  *
 148  * Arguments:   @key_file *f@ = key file to find a key from
 149  *              @const char *tag@ = pointer to tag string
 150  *
 151  * Returns:     Key with matching id or tag.
 152  *
 153  * Use:         Returns a key given its tag or id.  This function will return
 154  *              an expired key, but not a deleted one.
 155  */
 156
 157 key *key_bytag(key_file *f, const char *tag)
 158 {
 159   time_t t = time(0);
 160   char *p;
 161   uint32 id;
 162   key_ref *kr = sym_find(&f->bytag, tag, -1, 0, 0);
 163
 164   if (kr && !(KEY_EXPIRED(t, kr->k->exp) && KEY_EXPIRED(t, kr->k->del)))
 165     return (kr->k);
 166   id = strtoul(tag, &p, 16);
 167   if (!*p)
 168     return (key_byid(f, id));
 169   return (key_bytype(f, tag));
 170 }
 171
 172 /* --- @key_qtag@ --- *
 173  *
 174  * Arguments:   @key_file *f@ = key file to find a key from
 175  *              @const char *tag@ = pointer to tag string
 176  *              @dstr *d@ = pointer to string for full tag name
 177  *              @key **k@ = where to store the key pointer
 178  *              @key_data ***kd@ = where to store the key data pointer
 179  *
 180  * Returns:     Zero if OK, nonzero if it failed.
 181  *
 182  * Use:         Performs a full lookup on a qualified tag name.  The tag is
 183  *              qualified by the names of subkeys, separated by dots.  Hence,
 184  *              a qualified tag is ID|TAG[.TAG...].  The various result
 185  *              pointers can be null to indicate that the result isn't
 186  *              interesting.
 187  */
 188
 189 int key_qtag(key_file *f, const char *tag, dstr *d, key **k, key_data ***kd)
 190 {
 191   dstr dd = DSTR_INIT;
 192   const char *q;
 193   key *kk;
 194   key_data **kkd;
 195
 196   /* --- Find the end of the base tag --- */
 197
 198   if ((q = strchr(tag, '.')) == 0)
 199     DPUTS(&dd, tag);
 200   else {
 201     DPUTM(&dd, tag, q - tag);
 202     DPUTZ(&dd);
 203     q++;
 204   }
 205
 206   /* --- Look up the key tag --- */
 207
 208   if ((kk = key_bytag(f, dd.buf)) == 0) {
 209     dstr_destroy(&dd);
 210     return (-1);
 211   }
 212
 213   /* --- Set the various initial bits of result up --- */
 214
 215   if (d)
 216     key_fulltag(kk, d);
 217   if (k)
 218     *k = kk;
 219   kkd = &kk->k;
 220
 221   /* --- Now dig through the rest of the tag --- */
 222
 223   if (q) {
 224     while (*q) {
 225       key_struct *ks;
 226
 227       /* --- Stick on the next bit of the fullqtag --- */
 228
 229       DRESET(&dd);
 230       while (*q && *q != '.') {
 231         DPUTC(&dd, *q);
 232         q++;
 233       }
 234       DPUTZ(&dd);
 235       if (d) {
 236         DPUTC(d, '.');
 237         DPUTD(d, &dd);
 238       }
 239
 240       /* --- Look up the subkey --- */
 241
 242       if ((*kkd)->e != KENC_STRUCT) {
 243         kkd = 0;
 244         break;
 245       }
 246       if ((ks = sym_find(&(*kkd)->u.s, dd.buf, -1, 0, 0)) == 0) {
 247         kkd = 0;
 248         break;
 249       }
 250       kkd = &ks->k;
 251     }
 252   }
 253
 254   /* --- Return the results --- */
 255
 256   dstr_destroy(&dd);
 257   if (!kkd)
 258     return (-1);
 259   if (kd)
 260     *kd = kkd;
 261   return (0);
 262 }
 263
 264 /*----- Miscellaneous functions -------------------------------------------*/
 265
 266 /* --- @key_delete@ --- *
 267  *
 268  * Arguments:   @key_file *f@ = pointer to file block
 269  *              @key *k@ = key to delete
 270  *
 271  * Returns:     Error code (one of the @KERR@ constants).
 272  *
 273  * Use:         Removes the given key from the list.  The key file must be
 274  *              writable.  (Due to the horridness of the data structures,
 275  *              deleted keys aren't actually removed, just marked so that
 276  *              they can't be looked up or iterated over.  One upshot of
 277  *              this is that they don't get written back to the file when
 278  *              it's closed.)
 279  */
 280
 281 int key_delete(key_file *f, key *k)
 282 {
 283   KEY_WRITE(f);
 284   k->exp = KEXP_EXPIRE;
 285   k->del = KEXP_EXPIRE;
 286   KEY_MODIFY(f);
 287   return (0);
 288 }
 289
 290 /* --- @key_expired@ --- *
 291  *
 292  * Arguments:   @key *k@ = pointer to key block
 293  *
 294  * Returns:     Zero if the key is OK, nonzero if it's expired.
 295  */
 296
 297 int key_expired(key *k)
 298 {
 299   time_t now = time(0);
 300   return (KEY_EXPIRED(now, k->exp) || KEY_EXPIRED(now, k->del));
 301 }
 302
 303 /* --- @key_expire@ --- *
 304  *
 305  * Arguments:   @key_file *f@ = pointer to file block
 306  *              @key *k@ = pointer to key block
 307  *
 308  * Returns:     Error code (one of the @KERR@ constants).
 309  *
 310  * Use:         Immediately marks the key as expired.  It may be removed
 311  *              immediately, if it is no longer required, and will be removed
 312  *              by a tidy operation when it is no longer required.  The key
 313  *              file must be writable.
 314  */
 315
 316 int key_expire(key_file *f, key *k)
 317 {
 318   KEY_WRITE(f);
 319   k->exp = KEXP_EXPIRE;
 320   if (k->del == KEXP_FOREVER)
 321     k->del = KEXP_EXPIRE;
 322   KEY_MODIFY(f);
 323   return (0);
 324 }
 325
 326 /* --- @key_used@ --- *
 327  *
 328  * Arguments:   @key_file *f@ = pointer to key file
 329  *              @key *k@ = pointer to key block
 330  *              @time_t t@ = when key can be removed
 331  *
 332  * Returns:     Zero if OK, nonzero on failure.
 333  *
 334  * Use:         Marks a key as being required until a given time.  Even
 335  *              though the key may expire before then (and won't be returned
 336  *              by type after that time), it will still be available when
 337  *              requested explicitly by id.  The key file must be writable.
 338  *
 339  *              The only (current) reason for failure is attempting to use
 340  *              a key which can expire for something which can't.
 341  */
 342
 343 int key_used(key_file *f, key *k, time_t t)
 344 {
 345   KEY_WRITE(f);
 346   if (t == KEXP_FOREVER) {
 347     if (k->exp != KEXP_FOREVER)
 348       return (KERR_WILLEXPIRE);
 349   } else if (k->del >= t)
 350     return (0);
 351
 352   k->del = t;
 353   KEY_MODIFY(f);
 354   return (0);
 355 }
 356
 357 /* --- @key_fingerprint@ --- *
 358  *
 359  * Arguments:   @key *k@ = the key to fingerprint
 360  *              @ghash *h@ = the hash to use
 361  *              @const key_filter *kf@ = filter to apply
 362  *
 363  * Returns:     Nonzero if the key slightly matched the filter.
 364  *
 365  * Use:         Updates the hash context with the key contents.
 366  */
 367
 368 static int abyname(const void *a, const void *b) {
 369   key_attr *const *x = a, *const *y = b;
 370   return (strcmp(SYM_NAME(*x), SYM_NAME(*y)));
 371 }
 372
 373 int key_fingerprint(key *k, ghash *h, const key_filter *kf)
 374 {
 375   dstr d = DSTR_INIT;
 376   int rc = 0;
 377   key_attr *a, **v;
 378   size_t n, i;
 379   sym_iter ai;
 380
 381   if (!key_encode(k->k, &d, kf))
 382     goto done;
 383   rc = 1;
 384   GH_HASHSTR(h, "catacomb-key-fingerprint:");
 385   GH_HASHU32(h, k->id);
 386   GH_HASHSTR8(h, k->type);
 387   GH_HASH(h, d.buf, d.len);
 388   for (n = 0, sym_mkiter(&ai, &k->a); (a = sym_next(&ai)) != 0; n++);
 389   if (n) {
 390     v = xmalloc(n * sizeof(*v));
 391     for (i = 0, sym_mkiter(&ai, &k->a); (a = sym_next(&ai)) != 0; i++)
 392       v[i] = a;
 393     qsort(v, n, sizeof(*v), abyname);
 394     for (i = 0; i < n; i++) {
 395       GH_HASHSTR8(h, SYM_NAME(v[i]));
 396       GH_HASHSTR16(h, v[i]->p);
 397     }
 398     xfree(v);
 399   }
 400 done:
 401   dstr_destroy(&d);
 402   return (rc);
 403 }
 404
 405 /*----- That's all, folks -------------------------------------------------*/