mdw@git.distorted.org.uk Git - 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/macros.h>
  38 #include <mLib/sub.h>
  39 #include <mLib/sym.h>
  40
  41 #include "key.h"
  42
  43 /*----- Useful macros -----------------------------------------------------*/
  44
  45 #define KEY_WRITE(f) do {                                               \
  46      if (!((f)->f & KF_WRITE))                                          \
  47        return (KERR_READONLY);                                          \
  48    } while (0)
  49
  50 #define KEY_MODIFY(f) do { (f)->f |= KF_MODIFIED; } while (0)
  51
  52 #define KEY_LOAD(n) ((n) * 2)
  53
  54 /*----- Iteration and iterators -------------------------------------------*/
  55
  56 /* --- @key_mkiter@ --- *
  57  *
  58  * Arguments:   @key_iter *i@ = pointer to iterator object
  59  *              @key_file *f@ = pointer to file structure
  60  *
  61  * Returns:     ---
  62  *
  63  * Use:         Initializes a key iterator.  The keys are returned by
  64  *              @key_next@.
  65  */
  66
  67 void key_mkiter(key_iter *i, key_file *f)
  68 {
  69   HASH_MKITER(&i->i, &f->byid);
  70   i->t = time(0);
  71 }
  72
  73 /* --- @key_next@ --- *
  74  *
  75  * Arguments:   @key_iter *i@ = pointer to iterator object
  76  *
  77  * Returns:     Pointer to next key, or null.
  78  *
  79  * Use:         Returns the next key in some arbitrary sequence.
  80  */
  81
  82 key *key_next(key_iter *i)
  83 {
  84   hash_base *b;
  85   key *k;
  86   do {
  87     HASH_NEXT(&i->i, b);
  88     k = (key *)b;
  89   } while (k && KEY_EXPIRED(i->t, k->exp) && KEY_EXPIRED(i->t, k->del));
  90   return (k);
  91 }
  92
  93 /*----- Lookup ------------------------------------------------------------*/
  94
  95 /* --- @key_bytype@ --- *
  96  *
  97  * Arguments:   @key_file *f@ = key file we want a key from
  98  *              @const char *type@ = type string for desired key
  99  *
 100  * Returns:     Pointer to the best key to use, or null.
 101  *
 102  * Use:         Looks up a key by its type.  Returns the key with the latest
 103  *              expiry time.  This function will not return an expired key.
 104  */
 105
 106 key *key_bytype(key_file *f, const char *type)
 107 {
 108   time_t now = time(0);
 109   key *k;
 110   key_ref *kr;
 111
 112   if ((kr = sym_find(&f->bytype, type, -1, 0, 0)) == 0)
 113     return (0);
 114   for (k = kr->k; k && KEY_EXPIRED(now, k->exp); k = k->next)
 115     ;
 116   return (k);
 117 }
 118
 119 /* --- @key_byid@ --- *
 120  *
 121  * Arguments:   @key_file *f@ = key file to find a key from
 122  *              @uint32 id@ = id to look for
 123  *
 124  * Returns:     Key with matching id.
 125  *
 126  * Use:         Returns a key given its id.  This function will return an
 127  *              expired key, but not a deleted one.
 128  */
 129
 130 key *key_byid(key_file *f, uint32 id)
 131 {
 132   time_t t = time(0);
 133   hash_base **bin, *b;
 134
 135   bin = HASH_BIN(&f->byid, id);
 136   for (b = *bin; b; b = b->next) {
 137     if (b->hash == id) {
 138       key *k = (key *)b;
 139       if (KEY_EXPIRED(t, k->exp) && KEY_EXPIRED(t, k->del))
 140         return (0);
 141       return (k);
 142     }
 143   }
 144   return (0);
 145 }
 146
 147 /* --- @key_bytag@ --- *
 148  *
 149  * Arguments:   @key_file *f@ = key file to find a key from
 150  *              @const char *tag@ = pointer to tag string
 151  *
 152  * Returns:     Key with matching id or tag.
 153  *
 154  * Use:         Returns a key given its tag or id.  This function will return
 155  *              an expired key, but not a deleted one.
 156  */
 157
 158 key *key_bytag(key_file *f, const char *tag)
 159 {
 160   time_t t = time(0);
 161   char *p;
 162   uint32 id;
 163   enum { GUESS = -1, TAG, ID, TYPE }; int lookup;
 164   key_ref *kr;
 165   key *k;
 166
 167   if (STRNCMP(tag, ==, "tag:", 4)) { lookup = TAG; tag += 4; }
 168   else if (STRNCMP(tag, ==, "id:", 3)) { lookup = ID; tag += 3; }
 169   else if (STRNCMP(tag, ==, "type:", 5)) { lookup = TYPE; tag += 5; }
 170   else lookup = GUESS;
 171
 172   if ((lookup == GUESS || lookup == TAG) &&
 173       (kr = sym_find(&f->bytag, tag, -1, 0, 0)) != 0 &&
 174       !(KEY_EXPIRED(t, kr->k->exp) && KEY_EXPIRED(t, kr->k->del)))
 175     return (kr->k);
 176
 177   if (lookup == GUESS || lookup == ID) {
 178     id = strtoul(tag, &p, 16);
 179     if (!*p && (k = key_byid(f, id)) != 0) return (k);
 180   }
 181
 182   if ((lookup == GUESS || lookup == TYPE) && (k = key_bytype(f, tag)) != 0)
 183     return (k);
 184
 185   return (0);
 186 }
 187
 188 /* --- @key_qtag@ --- *
 189  *
 190  * Arguments:   @key_file *f@ = key file to find a key from
 191  *              @const char *tag@ = pointer to tag string
 192  *              @dstr *d@ = pointer to string for full tag name
 193  *              @key **k@ = where to store the key pointer
 194  *              @key_data ***kd@ = where to store the key data pointer
 195  *
 196  * Returns:     Zero if OK, nonzero if it failed.
 197  *
 198  * Use:         Performs a full lookup on a qualified tag name.  The tag is
 199  *              qualified by the names of subkeys, separated by dots.  Hence,
 200  *              a qualified tag is ID|TAG[.TAG...].  The various result
 201  *              pointers can be null to indicate that the result isn't
 202  *              interesting.
 203  */
 204
 205 int key_qtag(key_file *f, const char *tag, dstr *d, key **k, key_data ***kd)
 206 {
 207   dstr dd = DSTR_INIT;
 208   const char *q;
 209   key *kk;
 210   key_data **kkd;
 211
 212   /* --- Find the end of the base tag --- */
 213
 214   if ((q = strchr(tag, '.')) == 0)
 215     DPUTS(&dd, tag);
 216   else {
 217     DPUTM(&dd, tag, q - tag);
 218     DPUTZ(&dd);
 219     q++;
 220   }
 221
 222   /* --- Look up the key tag --- */
 223
 224   if ((kk = key_bytag(f, dd.buf)) == 0) {
 225     dstr_destroy(&dd);
 226     return (-1);
 227   }
 228
 229   /* --- Set the various initial bits of result up --- */
 230
 231   if (d)
 232     key_fulltag(kk, d);
 233   if (k)
 234     *k = kk;
 235   kkd = &kk->k;
 236
 237   /* --- Now dig through the rest of the tag --- */
 238
 239   if (q) {
 240     while (*q) {
 241       key_struct *ks;
 242
 243       /* --- Stick on the next bit of the fullqtag --- */
 244
 245       DRESET(&dd);
 246       while (*q && *q != '.') {
 247         DPUTC(&dd, *q);
 248         q++;
 249       }
 250       DPUTZ(&dd);
 251       if (d) {
 252         DPUTC(d, '.');
 253         DPUTD(d, &dd);
 254       }
 255
 256       /* --- Look up the subkey --- */
 257
 258       if ((*kkd)->e != KENC_STRUCT) {
 259         kkd = 0;
 260         break;
 261       }
 262       if ((ks = sym_find(&(*kkd)->u.s, dd.buf, -1, 0, 0)) == 0) {
 263         kkd = 0;
 264         break;
 265       }
 266       kkd = &ks->k;
 267     }
 268   }
 269
 270   /* --- Return the results --- */
 271
 272   dstr_destroy(&dd);
 273   if (!kkd)
 274     return (-1);
 275   if (kd)
 276     *kd = kkd;
 277   return (0);
 278 }
 279
 280 /*----- Miscellaneous functions -------------------------------------------*/
 281
 282 /* --- @key_delete@ --- *
 283  *
 284  * Arguments:   @key_file *f@ = pointer to file block
 285  *              @key *k@ = key to delete
 286  *
 287  * Returns:     Error code (one of the @KERR@ constants).
 288  *
 289  * Use:         Removes the given key from the list.  The key file must be
 290  *              writable.  (Due to the horridness of the data structures,
 291  *              deleted keys aren't actually removed, just marked so that
 292  *              they can't be looked up or iterated over.  One upshot of
 293  *              this is that they don't get written back to the file when
 294  *              it's closed.)
 295  */
 296
 297 int key_delete(key_file *f, key *k)
 298 {
 299   KEY_WRITE(f);
 300   k->exp = KEXP_EXPIRE;
 301   k->del = KEXP_EXPIRE;
 302   KEY_MODIFY(f);
 303   return (0);
 304 }
 305
 306 /* --- @key_expired@ --- *
 307  *
 308  * Arguments:   @key *k@ = pointer to key block
 309  *
 310  * Returns:     Zero if the key is OK, nonzero if it's expired.
 311  */
 312
 313 int key_expired(key *k)
 314 {
 315   time_t now = time(0);
 316   return (KEY_EXPIRED(now, k->exp) || KEY_EXPIRED(now, k->del));
 317 }
 318
 319 /* --- @key_expire@ --- *
 320  *
 321  * Arguments:   @key_file *f@ = pointer to file block
 322  *              @key *k@ = pointer to key block
 323  *
 324  * Returns:     Error code (one of the @KERR@ constants).
 325  *
 326  * Use:         Immediately marks the key as expired.  It may be removed
 327  *              immediately, if it is no longer required, and will be removed
 328  *              by a tidy operation when it is no longer required.  The key
 329  *              file must be writable.
 330  */
 331
 332 int key_expire(key_file *f, key *k)
 333 {
 334   KEY_WRITE(f);
 335   k->exp = KEXP_EXPIRE;
 336   if (k->del == KEXP_FOREVER)
 337     k->del = KEXP_EXPIRE;
 338   KEY_MODIFY(f);
 339   return (0);
 340 }
 341
 342 /* --- @key_used@ --- *
 343  *
 344  * Arguments:   @key_file *f@ = pointer to key file
 345  *              @key *k@ = pointer to key block
 346  *              @time_t t@ = when key can be removed
 347  *
 348  * Returns:     Zero if OK, nonzero on failure.
 349  *
 350  * Use:         Marks a key as being required until a given time.  Even
 351  *              though the key may expire before then (and won't be returned
 352  *              by type after that time), it will still be available when
 353  *              requested explicitly by id.  The key file must be writable.
 354  *
 355  *              The only (current) reason for failure is attempting to use
 356  *              a key which can expire for something which can't.
 357  */
 358
 359 int key_used(key_file *f, key *k, time_t t)
 360 {
 361   KEY_WRITE(f);
 362   if (t == KEXP_FOREVER) {
 363     if (k->exp != KEXP_FOREVER)
 364       return (KERR_WILLEXPIRE);
 365   } else if (k->del >= t)
 366     return (0);
 367
 368   k->del = t;
 369   KEY_MODIFY(f);
 370   return (0);
 371 }
 372
 373 /* --- @key_fingerprint@ --- *
 374  *
 375  * Arguments:   @key *k@ = the key to fingerprint
 376  *              @ghash *h@ = the hash to use
 377  *              @const key_filter *kf@ = filter to apply
 378  *
 379  * Returns:     Nonzero if the key slightly matched the filter.
 380  *
 381  * Use:         Updates the hash context with the key contents.
 382  */
 383
 384 static int abyname(const void *a, const void *b) {
 385   key_attr *const *x = a, *const *y = b;
 386   return (strcmp(SYM_NAME(*x), SYM_NAME(*y)));
 387 }
 388
 389 int key_fingerprint(key *k, ghash *h, const key_filter *kf)
 390 {
 391   dstr d = DSTR_INIT;
 392   int rc = 0;
 393   key_attr *a, **v;
 394   size_t n, i;
 395   sym_iter ai;
 396
 397   if (!key_encode(k->k, &d, kf))
 398     goto done;
 399   rc = 1;
 400   GH_HASHSTR(h, "catacomb-key-fingerprint:");
 401   GH_HASHU32(h, k->id);
 402   GH_HASHSTR8(h, k->type);
 403   GH_HASH(h, d.buf, d.len);
 404   for (n = 0, sym_mkiter(&ai, &k->a); (a = sym_next(&ai)) != 0; n++);
 405   if (n) {
 406     v = xmalloc(n * sizeof(*v));
 407     for (i = 0, sym_mkiter(&ai, &k->a); (a = sym_next(&ai)) != 0; i++)
 408       v[i] = a;
 409     qsort(v, n, sizeof(*v), abyname);
 410     for (i = 0; i < n; i++) {
 411       GH_HASHSTR8(h, SYM_NAME(v[i]));
 412       GH_HASHSTR16(h, v[i]->p);
 413     }
 414     xfree(v);
 415   }
 416 done:
 417   dstr_destroy(&d);
 418   return (rc);
 419 }
 420
 421 /*----- That's all, folks -------------------------------------------------*/