3 * Key loading and storing
5 * (c) 2001 Straylight/Edgeware
8 /*----- Licensing notice --------------------------------------------------*
10 * This file is part of Trivial IP Encryption (TrIPE).
12 * TrIPE is free software: you can redistribute it and/or modify it under
13 * the terms of the GNU General Public License as published by the Free
14 * Software Foundation; either version 3 of the License, or (at your
15 * option) any later version.
17 * TrIPE is distributed in the hope that it will be useful, but WITHOUT
18 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
19 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
22 * You should have received a copy of the GNU General Public License
23 * along with TrIPE. If not, see <https://www.gnu.org/licenses/>.
26 /*----- Header files ------------------------------------------------------*/
30 /*----- Algswitch stuff ---------------------------------------------------*/
32 /* --- @algs_get@ --- *
34 * Arguments: @algswitch *a@ = where to put the algorithms
35 * @dstr *e@ = where to write error tokens
36 * @key_file *kf@ = key file
37 * @key *k@ = key to inspect
39 * Returns: Zero if OK; nonzero on error.
41 * Use: Extracts an algorithm choice from a key.
44 static int algs_get(algswitch *a, dstr *e, key_file *kf, key *k)
48 dstr d = DSTR_INIT, dd = DSTR_INIT;
51 /* --- Hash function --- */
53 if ((p = key_getattr(kf, k, "hash")) == 0) p = "rmd160";
54 if ((a->h = ghash_byname(p)) == 0) {
55 a_format(e, "unknown-hash", "%s", p, A_END);
59 /* --- Symmetric encryption for key derivation --- */
61 if ((p = key_getattr(kf, k, "mgf")) == 0) {
63 dstr_putf(&d, "%s-mgf", a->h->name);
66 if ((a->mgf = gcipher_byname(p)) == 0) {
67 a_format(e, "unknown-mgf-cipher", "%s", p, A_END);
71 /* --- Bulk crypto transform --- */
73 if ((p = key_getattr(kf, k, "bulk")) == 0) p = "v0";
74 for (bops = bulktab; bops->name && strcmp(p, bops->name) != 0; bops++);
76 a_format(e, "unknown-bulk-transform", "%s", p, A_END);
79 if ((a->bulk = bops->getalgs(a, e, kf, k)) == 0) goto done;
82 /* --- All done --- */
91 /* --- @algs_check@ --- *
93 * Arguments: @algswitch *a@ = a choice of algorithms
94 * @dstr *e@ = where to write error tokens
95 * @const dhgrp *grp@ = the group we're working in
97 * Returns: Zero if OK; nonzero on error.
99 * Use: Checks an algorithm choice for sensibleness. This also
100 * derives some useful information from the choices, and you
101 * must call this before committing the algorithm selection
102 * for use by @keyset@ functions.
105 static int algs_check(algswitch *a, dstr *e, const dhgrp *grp)
107 a->hashsz = a->h->hashsz;
109 if (keysz(a->hashsz, a->mgf->keysz) != a->hashsz) {
110 a_format(e, "mgf", "%s", a->mgf->name,
111 "restrictive-key-schedule",
116 if (a->bulk->ops->checkalgs(a->bulk, a, e)) return (-1);
121 /* --- @km_samealgsp@ --- *
123 * Arguments: @const kdata *kdx, *kdy@ = two key data objects
125 * Returns: Nonzero if their two algorithm selections are the same.
127 * Use: Checks sameness of algorithm selections: used to ensure that
128 * peers are using sensible algorithms.
131 int km_samealgsp(const kdata *kdx, const kdata *kdy)
133 const algswitch *a = &kdx->algs, *aa = &kdy->algs;
135 return (kdx->grp->ops == kdy->grp->ops &&
136 kdx->grp->ops->samegrpp(kdx->grp, kdy->grp) &&
137 a->mgf == aa->mgf && a->h == aa->h &&
138 a->bulk->ops == aa->bulk->ops &&
139 a->bulk->ops->samealgsp(a->bulk, aa->bulk));
142 /*----- Key data and key nodes --------------------------------------------*/
144 typedef struct keyhalf {
146 int (*load)(key_file *, key *, key_data *,
147 const dhops *, kdata *, dstr *, dstr *);
154 /* --- @kh_loadpub@, @kh_loadpriv@ --- *
156 * Arguments: @const dhops *dh@ = Diffie--Hellman operations for key type
157 * @key_file *kf@ = key file from which the key was loaded
158 * @key *k@ = the key object we're loading
159 * @key_data *d@ = the key data to load
160 * @kdata *kd@ = our key-data object to fill in
161 * @dstr *t@ = the key tag name
162 * @dstr *e@ = a string to write error tokens to
164 * Returns: Zero on success, @-1@ on error.
166 * Use: These functions handle the main difference between public and
167 * private key halves. They are responsible for setting @grp@,
168 * @k@ and @K@ appropriately in all keys, handling the mismatch
169 * between the largely half-indifferent calling code and the
170 * group-specific loading functions.
172 * The function @kh_loadpriv@ is also responsible for checking
173 * the group for goodness. We don't bother checking public
174 * keys, because each public key we actually end up using must
175 * share a group with a private key which we'll already have
179 static int kh_loadpub(key_file *kf, key *k, key_data *d,
180 const dhops *dh, kdata *kd, dstr *t, dstr *e)
184 if ((rc = dh->ldpub(kf, k, d, kd, t, e)) != 0)
187 if (kd->grp->ops->checkge(kd->grp, kd->K)) {
188 a_format(e, "bad-public-group-element", A_END);
194 kd->grp->ops->freege(kd->grp, kd->K);
195 kd->grp->ops->freegrp(kd->grp);
200 static int kh_loadpriv(key_file *kf, key *k, key_data *d,
201 const dhops *dh, kdata *kd, dstr *t, dstr *e)
208 if ((rc = dh->ldpriv(kf, k, d, kd, t, e)) != 0)
211 if ((err = kd->grp->ops->checkgrp(kd->grp)) != 0) {
212 a_format(e, "bad-group", "%s", err, A_END);
215 K = kd->grp->ops->mul(kd->grp, kd->k, 0);
216 ok = kd->grp->ops->eq(kd->grp, kd->K, K);
217 kd->grp->ops->freege(kd->grp, K);
219 a_format(e, "incorrect-public-key", A_END);
225 kd->grp->ops->freesc(kd->grp, kd->k);
226 kd->grp->ops->freege(kd->grp, kd->K);
227 kd->grp->ops->freegrp(kd->grp);
232 static struct keyhalf
233 priv = { "private", kh_loadpriv },
234 pub = { "public", kh_loadpub };
236 /* --- @keymoan@ --- *
238 * Arguments: @const char *file@ = name of the file
239 * @int line@ = line number in file
240 * @const char *msg@ = error message
241 * @void *p@ = argument pointer (indicates which keyring)
245 * Use: Reports an error message about loading a key file.
248 static void keymoan(const char *file, int line, const char *msg, void *p)
253 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", file,
254 "io-error", "?ERRNO", A_END);
256 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", file, "line", "%d", line,
261 /* --- @kh_reopen@ --- *
263 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure
265 * Returns: Zero on success, @-1@ on error.
267 * Use: Reopens the key file for the appropriate key half. If this
268 * fails, everything is left as it was; if it succeeds, then the
269 * old file is closed (if it was non-null) and the new one put
273 static int kh_reopen(keyhalf *kh)
275 key_file *kf = CREATE(key_file);
277 if (key_open(kf, kh->kr, KOPEN_READ, keymoan, kh)) {
278 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", kh->kr,
279 "io-error", "?ERRNO", A_END);
292 /* --- @kh_init@ --- *
294 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure to set up
295 * @const char *kr@ = name of the keyring file
299 * Use: Initialize a keyhalf structure, maintaining the private or
300 * public keys. Intended to be called during initialization:
301 * exits if there's some kind of problem.
304 static void kh_init(keyhalf *kh, const char *kr)
307 fwatch_init(&kh->w, kr);
308 sym_create(&kh->tab);
312 die(EXIT_FAILURE, "failed to load %s keyring `%s'", kh->kind, kr);
315 /* --- @kh_load@ --- *
317 * Arguments: @keyhalf *kh@ = pointer to keyhalf
318 * @const char *tag@ = key tag to be loaded
319 * @int complainp@ = whether to complain about missing keys
321 * Returns: Pointer to a @kdata@ structure if successful, or null on
324 * Use: Attempts to load a key from the current key file. This
325 * function always reads data from the file: it's used when
326 * there's a cache miss from @kh_find@, and when refreshing the
327 * known keys in @kh_refresh@. The returned kdata has a
328 * reference count of exactly 1, and has no home knode.
331 static kdata *kh_load(keyhalf *kh, const char *tag, int complainp)
342 /* --- Find the key and grab its tag --- */
344 if (key_qtag(kh->kf, tag, &t, &k, &d)) {
346 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", kh->kr,
347 "key-not-found", "%s", tag, A_END);
352 /* --- Find the key's group type and the appropriate operations --- *
354 * There are several places to look for the key type. The most obvious is
355 * the `kx-group' key attribute. But there's also the key type itself, for
356 * compatibility reasons.
359 ty = key_getattr(kh->kf, k, "kx-group");
360 if (!ty && strncmp(k->type, "tripe-", 6) == 0) ty = k->type + 6;
363 for (dh = dhtab; dh->name; dh++)
364 if (strcmp(dh->name, ty) == 0) goto founddh;
365 a_warn("KEYMGMT", "%s-keyring", kh->kind,
366 "%s", kh->kr, "key", "%s", t.buf,
367 "unknown-group-type", "%s", ty, A_END);
372 if (kh->load(kh->kf, k, *d, dh, kd, &t, &e)) {
373 a_warn("KEYMGMT", "%s-keyring", kh->kind,
374 "%s", kh->kr, "key", "%s", t.buf,
375 "*%s", e.buf, A_END);
379 if (algs_get(&kd->algs, &e, kh->kf, k) ||
380 algs_check(&kd->algs, &e, kd->grp)) {
381 a_warn("KEYMGMT", "%s-keyring", kh->kind,
382 "%s", kh->kr, "key", "%s", t.buf,
383 "*%s", e.buf, A_END);
387 kd->tag = xstrdup(t.buf);
392 IF_TRACING(T_KEYMGMT, {
393 trace(T_KEYMGMT, "keymgmt: loaded %s key `%s'", kh->kind, t.buf);
394 IF_TRACING(T_CRYPTO, {
398 trace(T_CRYPTO, "crypto: k = %s", g->ops->scstr(g, kd->k));
399 trace(T_CRYPTO, "crypto: K = %s", g->ops->gestr(g, kd->K));
400 kd->algs.bulk->ops->tracealgs(kd->algs.bulk);
407 if (kd->k) kd->grp->ops->freesc(kd->grp, kd->k);
408 kd->grp->ops->freege(kd->grp, kd->K);
409 kd->grp->ops->freegrp(kd->grp);
420 /* --- @kh_find@ --- *
422 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
423 * @const char *tag@ = key to be obtained
424 * @int complainp@ = whether to complain about missing keys
426 * Returns: A pointer to the kdata, or null on error.
428 * Use: Obtains kdata, maybe from the cache. This won't update a
429 * stale cache entry, though @kh_refresh@ ought to have done
430 * that already. The returned kdata object may be shared with
431 * other users. (One of this function's responsibilities, over
432 * @kh_load@, is to set the home knode of a freshly loaded
436 static kdata *kh_find(keyhalf *kh, const char *tag, int complainp)
442 kn = sym_find(&kh->tab, tag, -1, sizeof(knode), &f);
445 if (kn->f & KNF_BROKEN) {
447 trace(T_KEYMGMT, "keymgmt: key `%s' marked as broken", tag); )
453 T( trace(T_KEYMGMT, "keymgmt: %scache hit for key `%s'",
454 kd ? "" : "negative ", tag); )
457 kd = kh_load(kh, tag, complainp);
471 /* --- @kh_refresh@ --- *
473 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
475 * Returns: Zero if nothing needs to be done; nonzero if peers should
476 * refresh their keys.
478 * Use: Refreshes cached keys from files.
480 * Each active knode is examined to see if a new key is
481 * available: the return value is nonzero if any new keys are.
482 * A key is considered new if its algorithms, public key, or
483 * expiry time are/is different.
485 * Stub knodes (with no kdata attached) are removed, so that a
486 * later retry can succeed if the file has been fixed. (This
487 * doesn't count as a change, since no peers should be relying
488 * on a nonexistent key.)
491 static int kh_refresh(keyhalf *kh)
498 if (!fwatch_update(&kh->w, kh->kr) || kh_reopen(kh))
501 T( trace(T_KEYMGMT, "keymgmt: rescan %s keyring `%s'", kh->kind, kh->kr); )
502 for (sym_mkiter(&i, &kh->tab); (kn = sym_next(&i)) != 0; ) {
504 T( trace(T_KEYMGMT, "keymgmt: discard stub entry for key `%s'",
506 sym_remove(&kh->tab, kn);
509 if ((kd = kh_load(kh, SYM_NAME(kn), 1)) == 0) {
510 if (!(kn->f & KNF_BROKEN)) {
511 T( trace(T_KEYMGMT, "keymgmt: failed to load new key `%s': "
512 "marking it as broken",
518 kn->f &= ~KNF_BROKEN;
519 if (kd->t_exp == kn->kd->t_exp &&
520 km_samealgsp(kd, kn->kd) &&
521 kd->grp->ops->eq(kd->grp, kd->K, kn->kd->K)) {
522 T( trace(T_KEYMGMT, "keymgmt: key `%s' unchanged", SYM_NAME(kn)); )
525 T( trace(T_KEYMGMT, "keymgmt: loaded new version of key `%s'",
536 /*----- Main code ---------------------------------------------------------*/
538 const char *tag_priv;
541 /* --- @km_init@ --- *
543 * Arguments: @const char *privkr@ = private keyring file
544 * @const char *pubkr@ = public keyring file
545 * @const char *ptag@ = default private-key tag
549 * Use: Initializes the key-management machinery, loading the
550 * keyrings and so on.
553 void km_init(const char *privkr, const char *pubkr, const char *ptag)
555 const gchash *const *hh;
557 for (hh = ghashtab; *hh; hh++) {
558 if ((*hh)->hashsz > MAXHASHSZ) {
559 die(EXIT_FAILURE, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d",
560 (*hh)->name, (unsigned long)(*hh)->hashsz, MAXHASHSZ);
564 kh_init(&priv, privkr);
565 kh_init(&pub, pubkr);
568 if ((master = km_findpriv(ptag)) == 0) exit(EXIT_FAILURE);
571 /* --- @km_reload@ --- *
575 * Returns: Zero if OK, nonzero to force reloading of keys.
577 * Use: Checks the keyrings to see if they need reloading.
585 if (kh_refresh(&priv)) {
594 if (kh_refresh(&pub))
599 /* --- @km_findpub@, @km_findpriv@ --- *
601 * Arguments: @const char *tag@ = key tag to load
603 * Returns: Pointer to the kdata object if successful, or null on error.
605 * Use: Fetches a public or private key from the keyring.
608 kdata *km_findpub(const char *tag) { return (kh_find(&pub, tag, 1)); }
610 kdata *km_findpriv(const char *tag)
614 /* Unpleasantness for the sake of compatibility. */
615 if (!tag && (kd = kh_find(&priv, "tripe", 0)) != 0) return (kd);
616 else return (kh_find(&priv, tag ? tag : "tripe-dh", 1));
619 /* --- @km_tag@ --- *
621 * Arguments: @kdata *kd@ - pointer to the kdata object
623 * Returns: A pointer to the short tag by which the kdata was loaded.
626 const char *km_tag(kdata *kd) { return (SYM_NAME(kd->kn)); }
628 /* --- @km_ref@ --- *
630 * Arguments: @kdata *kd@ = pointer to the kdata object
634 * Use: Claim a new reference to a kdata object.
637 void km_ref(kdata *kd) { kd->ref++; }
639 /* --- @km_unref@ --- *
641 * Arguments: @kdata *kd@ = pointer to the kdata object
645 * Use: Releases a reference to a kdata object.
648 void km_unref(kdata *kd)
650 if (--kd->ref) return;
651 if (kd->k) kd->grp->ops->freesc(kd->grp, kd->k);
652 kd->grp->ops->freege(kd->grp, kd->K);
653 kd->grp->ops->freegrp(kd->grp);
658 /*----- That's all, folks -------------------------------------------------*/