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
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * TrIPE 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 General Public License for more details.
22 * You should have received a copy of the GNU General Public License
23 * along with TrIPE; if not, write to the Free Software Foundation,
24 * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
27 /*----- Header files ------------------------------------------------------*/
31 /*----- Key groups --------------------------------------------------------*/
33 /* The key-loading functions here must fill in the kdata slot @g@ and
34 * either @kpriv@ or @kpub@ as appropriate. The caller will take care of
35 * determining @kpub@ given a private key, and of ensuring that @kpriv@ is
36 * null for a public key.
39 typedef struct kgops {
41 int (*loadpriv)(key_data *, kdata *, dstr *, dstr *);
42 int (*loadpub)(key_data *, kdata *, dstr *, dstr *);
47 * Arguments: @ty@, @TY@ = key type name (lower- and upper-case)
48 * @which@, @WHICH@ = `pub' or `priv' (and upper-case)
49 * @setgroup@ = code to initialize @kd->g@
50 * @setpriv@ = code to initialize @kd->kpriv@
51 * @setpub@ = code to initialize @kd->kpub@
53 * Use: Generates the body of one of the (rather tedious) key loading
54 * functions. See the description of @KEYTYPES@ below for the
58 #define KLOAD(ty, TY, which, WHICH, setgroup, setpriv, setpub) \
59 static int kg##ty##_##which(key_data *d, kdata *kd, dstr *t, dstr *e) \
61 key_packstruct kps[TY##_##WHICH##FETCHSZ]; \
66 /* --- Initialize things we've not set up yet --- */ \
68 kd->g = 0; kd->kpub = 0; \
70 /* --- Unpack the key --- */ \
72 kp = key_fetchinit(ty##_##which##fetch, kps, &p); \
73 if ((rc = key_unpack(kp, d, t)) != 0) { \
74 a_format(e, "unpack-failed", "%s", key_strerror(rc), A_END); \
78 /* --- Extract the pieces of the key --- */ \
82 kd->kpub = G_CREATE(kd->g); \
85 /* --- We win --- */ \
91 if (kd->kpub) G_DESTROY(kd->g, kd->kpub); \
92 if (kd->g) G_DESTROYGROUP(kd->g); \
100 /* --- @KEYTYPES@ --- *
102 * A list of the various key types, and how to unpack them. Each entry in
103 * the list has the form
105 * _(ty, TY, setgroup, setpriv, setpub)
107 * The @ty@ and @TY@ are lower- and upper-case versions of the key type name,
108 * and there should be @key_fetchdef@s called @ty_{priv,pub}fetch@.
110 * The @setgroup@, @setpriv@ and @setpub@ items are code fragments which are
111 * passed to @KLOAD@ to build appropriate key-loading methods. By the time
112 * these code fragments are run, the key has been unpacked from the incoming
113 * key data using @ty_whichfetch@ into a @ty_which@ structure named @p@.
114 * They can report errors by writing an appropriate token sequence to @e@ and
118 #define KEYTYPES(_) \
120 /* --- Diffie-Hellman --- */ \
123 { kd->g = group_prime(&p.dp); }, \
124 { kd->kpriv = MP_COPY(p.x); }, \
125 { if (G_FROMINT(kd->g, kd->kpub, p.y)) { \
126 a_format(e, "bad-public-vector", A_END); \
131 /* --- Elliptic curves --- */ \
134 { ec_info ei; const char *err; \
135 if ((err = ec_getinfo(&ei, p.cstr)) != 0) { \
136 a_format(e, "decode-failed", "%s", err, A_END); \
139 kd->g = group_ec(&ei); \
141 { kd->kpriv = MP_COPY(p.x); }, \
142 { if (G_FROMEC(kd->g, kd->kpub, &p.p)) { \
143 a_format(e, "bad-public-vector", A_END); \
148 #define KEYTYPE_DEF(ty, TY, setgroup, setpriv, setpub) \
149 KLOAD(ty, TY, priv, PRIV, setgroup, setpriv, \
150 { G_EXP(kd->g, kd->kpub, kd->g->g, kd->kpriv); }) \
151 KLOAD(ty, TY, pub, PUB, setgroup, { }, setpub) \
152 static const kgops kg##ty##_ops = { #ty, kg##ty##_priv, kg##ty##_pub };
153 KEYTYPES(KEYTYPE_DEF)
155 /* --- Table of supported key types --- */
157 static const kgops *kgtab[] = {
158 #define KEYTYPE_ENTRY(ty, TY, setgroup, setpriv, setpub) &kg##ty##_ops,
159 KEYTYPES(KEYTYPE_ENTRY)
164 /*----- Algswitch stuff ---------------------------------------------------*/
166 /* --- @algs_get@ --- *
168 * Arguments: @algswitch *a@ = where to put the algorithms
169 * @dstr *e@ = where to write errror tokens
170 * @key_file *kf@ = key file
171 * @key *k@ = key to inspect
173 * Returns: Zero if OK; nonzero on error.
175 * Use: Extracts an algorithm choice from a key.
178 static int algs_get(algswitch *a, dstr *e, key_file *kf, key *k)
181 const bulkcrypto *bulk;
186 /* --- Hash function --- */
188 if ((p = key_getattr(kf, k, "hash")) == 0) p = "rmd160";
189 if ((a->h = ghash_byname(p)) == 0) {
190 a_format(e, "unknown-hash", "%s", p, A_END);
194 /* --- Symmetric encryption for key derivation --- */
196 if ((p = key_getattr(kf, k, "mgf")) == 0) {
198 dstr_putf(&d, "%s-mgf", a->h->name);
201 if ((a->mgf = gcipher_byname(p)) == 0) {
202 a_format(e, "unknown-mgf-cipher", "%s", p, A_END);
206 /* --- Bulk crypto transform --- */
208 if ((p = key_getattr(kf, k, "bulk")) == 0) p = "v0";
209 for (bulk = bulktab; bulk->name && strcmp(p, bulk->name) != 0; bulk++);
211 a_format(e, "unknown-bulk-transform", "%s", p, A_END);
216 /* --- Symmetric encryption for bulk data --- */
218 if (!(a->bulk->prim & BCP_CIPHER))
221 if ((p = key_getattr(kf, k, "cipher")) == 0) p = "blowfish-cbc";
222 if ((a->c = gcipher_byname(p)) == 0) {
223 a_format(e, "unknown-cipher", "%s", p, A_END);
228 /* --- Message authentication for bulk data --- */
230 if (!(a->bulk->prim & BCP_MAC)) {
234 if ((p = key_getattr(kf, k, "mac")) != 0) {
237 if ((q = strchr(d.buf, '/')) != 0)
239 if ((a->m = gmac_byname(d.buf)) == 0) {
240 a_format(e, "unknown-mac", "%s", d.buf, A_END);
244 a->tagsz = a->m->hashsz;
246 unsigned long n = strtoul(q, &qq, 0);
248 a_format(e, "bad-tag-length-string", "%s", q, A_END);
251 if (n%8 || n/8 > a->m->hashsz) {
252 a_format(e, "bad-tag-length", "%lu", n, A_END);
259 dstr_putf(&d, "%s-hmac", a->h->name);
260 if ((a->m = gmac_byname(d.buf)) == 0) {
261 a_format(e, "no-hmac-for-hash", "%s", a->h->name, A_END);
264 a->tagsz = a->h->hashsz/2;
268 /* --- All done --- */
276 /* --- @algs_check@ --- *
278 * Arguments: @algswitch *a@ = a choice of algorithms
279 * @dstr *e@ = where to write error tokens
280 * @const group *g@ = the group we're working in
282 * Returns: Zero if OK; nonzero on error.
284 * Use: Checks an algorithm choice for sensibleness. This also
285 * derives some useful information from the choices, and you
286 * must call this before committing the algorithm selection
287 * for use by @keyset@ functions.
290 static int algs_check(algswitch *a, dstr *e, const group *g)
292 /* --- Check the bulk crypto transform --- */
294 if (a->bulk->check(a, e)) return (-1);
296 /* --- Derive the key sizes --- *
298 * Must ensure that we have non-empty keys. This isn't ideal, but it
299 * provides a handy sanity check. Also must be based on a 64- or 128-bit
300 * block cipher or we can't do the data expiry properly.
303 a->hashsz = a->h->hashsz;
304 if (a->c && (a->cksz = keysz(a->hashsz, a->c->keysz)) == 0) {
305 a_format(e, "cipher", "%s", a->c->name,
306 "no-key-size", "%lu", (unsigned long)a->hashsz,
310 if (a->m && (a->mksz = keysz(a->hashsz, a->m->keysz)) == 0) {
311 a_format(e, "mac", "%s", a->m->name,
312 "no-key-size", "%lu", (unsigned long)a->hashsz,
317 /* --- Derive the data limit --- */
319 if (a->c && a->c->blksz < 16) a->expsz = MEG(64);
320 else a->expsz = MEG(2048);
322 /* --- Ensure the MGF accepts hashes as keys --- */
324 if (keysz(a->hashsz, a->mgf->keysz) != a->hashsz) {
325 a_format(e, "mgf", "%s", a->mgf->name,
326 "restrictive-key-schedule",
331 /* --- All ship-shape and Bristol-fashion --- */
336 /* --- @km_samealgsp@ --- *
338 * Arguments: @const kdata *kdx, *kdy@ = two key data objects
340 * Returns: Nonzero if their two algorithm selections are the same.
342 * Use: Checks sameness of algorithm selections: used to ensure that
343 * peers are using sensible algorithms.
346 int km_samealgsp(const kdata *kdx, const kdata *kdy)
348 const algswitch *a = &kdx->algs, *aa = &kdy->algs;
350 return (group_samep(kdx->g, kdy->g) && a->c == aa->c &&
351 a->mgf == aa->mgf && a->h == aa->h &&
352 a->m == aa->m && a->tagsz == aa->tagsz);
355 /*----- Key data and key nodes --------------------------------------------*/
357 typedef struct keyhalf {
359 int (*load)(const kgops *, key_data *, kdata *, dstr *, dstr *);
366 /* --- @kh_loadpub@, @kh_loadpriv@ --- *
368 * Arguments: @const kgops *ko@ = key-group operations for key type
369 * @key_data *d@ = key data object as stored in keyring
370 * @kdata *kd@ = our key-data object to fill in
371 * @dstr *t@ = the key tag name
372 * @dstr *e@ = a string to write error tokens to
374 * Returns: Zero on success, @-1@ on error.
376 * Use: These functions handle the main difference between public and
377 * private key halves. They are responsible for setting @g@,
378 * @kpriv@ and @kpub@ appropriately in all keys, handling the
379 * mismatch between the largely half-indifferent calling code
380 * and the group-specific loading functions.
382 * The function @kh_loadpriv@ is also responsible for checking
383 * the group for goodness. We don't bother checking public
384 * keys, because each public key we actually end up using must
385 * share a group with a private key which we'll already have
389 static int kh_loadpub(const kgops *ko, key_data *d, kdata *kd,
394 if ((rc = ko->loadpub(d, kd, t, e)) != 0)
396 if (group_check(kd->g, kd->kpub)) {
397 a_format(e, "bad-public-group-element", A_END);
404 G_DESTROY(kd->g, kd->kpub);
405 G_DESTROYGROUP(kd->g);
410 static int kh_loadpriv(const kgops *ko, key_data *d, kdata *kd,
416 if ((rc = ko->loadpriv(d, kd, t, e)) != 0)
418 if ((err = G_CHECK(kd->g, &rand_global)) != 0) {
419 a_format(e, "bad-group", "%s", err, A_END);
426 G_DESTROY(kd->g, kd->kpub);
427 G_DESTROYGROUP(kd->g);
432 static struct keyhalf
433 priv = { "private", kh_loadpriv },
434 pub = { "public", kh_loadpub };
436 /* --- @keymoan@ --- *
438 * Arguments: @const char *file@ = name of the file
439 * @int line@ = line number in file
440 * @const char *msg@ = error message
441 * @void *p@ = argument pointer (indicates which keyring)
445 * Use: Reports an error message about loading a key file.
448 static void keymoan(const char *file, int line, const char *msg, void *p)
453 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", file,
454 "io-error", "?ERRNO", A_END);
456 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", file, "line", "%d", line,
461 /* --- @kh_reopen@ --- *
463 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure
465 * Returns: Zero on success, @-1@ on error.
467 * Use: Reopens the key file for the appropriate key half. If this
468 * fails, everything is left as it was; if it succeeds, then the
469 * old file is closed (if it was non-null) and the new one put
473 static int kh_reopen(keyhalf *kh)
475 key_file *kf = CREATE(key_file);
477 if (key_open(kf, kh->kr, KOPEN_READ, keymoan, kh)) {
478 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", kh->kr,
479 "io-error", "?ERRNO", A_END);
492 /* --- @kh_init@ --- *
494 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure to set up
495 * @const char *kr@ = name of the keyring file
499 * Use: Initialize a keyhalf structure, maintaining the private or
500 * public keys. Intended to be called during initialization:
501 * exits if there's some kind of problem.
504 static void kh_init(keyhalf *kh, const char *kr)
507 fwatch_init(&kh->w, kr);
508 sym_create(&kh->tab);
512 die(EXIT_FAILURE, "failed to load %s keyring `%s'", kh->kind, kr);
515 /* --- @kh_load@ --- *
517 * Arguments: @keyhalf *kh@ = pointer to keyhalf
518 * @const char *tag@ = key tag to be loaded
519 * @int complainp@ = whether to complain about missing keys
521 * Returns: Pointer to a @kdata@ structure if successful, or null on
524 * Use: Attempts to load a key from the current key file. This
525 * function always reads data from the file: it's used when
526 * there's a cache miss from @kh_find@, and when refreshing the
527 * known keys in @kh_refresh@. The returned kdata has a
528 * reference count of exactly 1, and has no home knode.
531 static kdata *kh_load(keyhalf *kh, const char *tag, int complainp)
541 /* --- Find the key and grab its tag --- */
543 if (key_qtag(kh->kf, tag, &t, &k, &d)) {
545 a_warn("KEYMGMT", "%s-keyring", kh->kind, "%s", kh->kr,
546 "key-not-found", "%s", tag, A_END);
551 /* --- Find the key's group type and the appropriate operations --- *
553 * There are several places to look for the key type. The most obvious is
554 * the `kx-group' key attribute. But there's also the key type itself, for
555 * compatibility reasons.
558 ty = key_getattr(kh->kf, k, "kx-group");
559 if (!ty && strncmp(k->type, "tripe-", 6) == 0) ty = k->type + 6;
562 for (ko = kgtab; *ko; ko++)
563 if (strcmp((*ko)->ty, ty) == 0) goto foundko;
564 a_warn("KEYMGMT", "%s-keyring", kh->kind,
565 "%s", kh->kr, "key", "%s", t.buf,
566 "unknown-group-type", "%s", ty, A_END);
571 if (kh->load(*ko, *d, kd, &t, &e)) {
572 a_warn("KEYMGMT", "%s-keyring", kh->kind,
573 "%s", kh->kr, "key" "%s", t.buf,
574 "*%s", e.buf, A_END);
578 if (algs_get(&kd->algs, &e, kh->kf, k) ||
579 (kd->kpriv && algs_check(&kd->algs, &e, kd->g))) {
580 a_warn("KEYMGMT", "%s-keyring", kh->kind,
581 "%s", kh->kr, "key", "%s", t.buf,
582 "*%s", e.buf, A_END);
586 kd->tag = xstrdup(t.buf);
587 kd->indexsz = mp_octets(kd->g->r);
592 IF_TRACING(T_KEYMGMT, {
593 trace(T_KEYMGMT, "keymgmt: loaded %s key `%s'", kh->kind, t.buf);
594 IF_TRACING(T_CRYPTO, {
595 trace(T_CRYPTO, "crypto: r = %s", mpstr(kd->g->r));
596 trace(T_CRYPTO, "crypto: h = %s", mpstr(kd->g->h));
598 trace(T_CRYPTO, "crypto: x = %s", mpstr(kd->kpriv));
599 trace(T_CRYPTO, "crypto: cipher = %s", kd->algs.c->name);
600 trace(T_CRYPTO, "crypto: mgf = %s", kd->algs.mgf->name);
601 trace(T_CRYPTO, "crypto: hash = %s", kd->algs.h->name);
602 trace(T_CRYPTO, "crypto: mac = %s/%lu",
603 kd->algs.m->name, (unsigned long)kd->algs.tagsz * 8);
610 if (kd->kpriv) mp_drop(kd->kpriv);
611 G_DESTROY(kd->g, kd->kpub);
612 G_DESTROYGROUP(kd->g);
623 /* --- @kh_find@ --- *
625 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
626 * @const char *tag@ = key to be obtained
627 * @int complainp@ = whether to complain about missing keys
629 * Returns: A pointer to the kdata, or null on error.
631 * Use: Obtains kdata, maybe from the cache. This won't update a
632 * stale cache entry, though @kh_refresh@ ought to have done
633 * that already. The returned kdata object may be shared with
634 * other users. (One of this function's responsibilities, over
635 * @kh_load@, is to set the home knode of a freshly loaded
639 static kdata *kh_find(keyhalf *kh, const char *tag, int complainp)
645 kn = sym_find(&kh->tab, tag, -1, sizeof(knode), &f);
648 if (kn->f & KNF_BROKEN) {
650 trace(T_KEYMGMT, "keymgmt: key `%s' marked as broken", tag); )
656 T( trace(T_KEYMGMT, "keymgmt: %scache hit for key `%s'",
657 kd ? "" : "negative ", tag); )
660 kd = kh_load(kh, tag, complainp);
674 /* --- @kh_refresh@ --- *
676 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
678 * Returns: Zero if nothing needs to be done; nonzero if peers should
679 * refresh their keys.
681 * Use: Refreshes cached keys from files.
683 * Each active knode is examined to see if a new key is
684 * available: the return value is nonzero if any new keys are.
685 * A key is considered new if its algorithms, public key, or
686 * expiry time are/is different.
688 * Stub knodes (with no kdata attached) are removed, so that a
689 * later retry can succeed if the file has been fixed. (This
690 * doesn't count as a change, since no peers should be relying
691 * on a nonexistent key.)
694 static int kh_refresh(keyhalf *kh)
701 if (!fwatch_update(&kh->w, kh->kr) || kh_reopen(kh))
704 T( trace(T_KEYMGMT, "keymgmt: rescan %s keyring `%s'", kh->kind, kh->kr); )
705 for (sym_mkiter(&i, &kh->tab); (kn = sym_next(&i)) != 0; ) {
707 T( trace(T_KEYMGMT, "keymgmt: discard stub entry for key `%s'",
709 sym_remove(&kh->tab, kn);
712 if ((kd = kh_load(kh, SYM_NAME(kn), 1)) == 0) {
713 if (!(kn->f & KNF_BROKEN)) {
714 T( trace(T_KEYMGMT, "keymgmt: failed to load new key `%s': "
715 "marking it as broken",
721 kn->f &= ~KNF_BROKEN;
722 if (kd->t_exp == kn->kd->t_exp &&
723 km_samealgsp(kd, kn->kd) &&
724 G_EQ(kd->g, kd->kpub, kn->kd->kpub)) {
725 T( trace(T_KEYMGMT, "keymgmt: key `%s' unchanged", SYM_NAME(kn)); )
728 T( trace(T_KEYMGMT, "keymgmt: loaded new version of key `%s'",
739 /*----- Main code ---------------------------------------------------------*/
741 const char *tag_priv;
744 /* --- @km_init@ --- *
746 * Arguments: @const char *privkr@ = private keyring file
747 * @const char *pubkr@ = public keyring file
748 * @const char *ptag@ = default private-key tag
752 * Use: Initializes the key-management machinery, loading the
753 * keyrings and so on.
756 void km_init(const char *privkr, const char *pubkr, const char *ptag)
758 const gchash *const *hh;
760 for (hh = ghashtab; *hh; hh++) {
761 if ((*hh)->hashsz > MAXHASHSZ) {
762 die(EXIT_FAILURE, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d",
763 (*hh)->name, (unsigned long)(*hh)->hashsz, MAXHASHSZ);
767 kh_init(&priv, privkr);
768 kh_init(&pub, pubkr);
771 if ((master = km_findpriv(ptag)) == 0) exit(EXIT_FAILURE);
774 /* --- @km_reload@ --- *
778 * Returns: Zero if OK, nonzero to force reloading of keys.
780 * Use: Checks the keyrings to see if they need reloading.
788 if (kh_refresh(&priv)) {
797 if (kh_refresh(&pub))
802 /* --- @km_findpub@, @km_findpriv@ --- *
804 * Arguments: @const char *tag@ = key tag to load
806 * Returns: Pointer to the kdata object if successful, or null on error.
808 * Use: Fetches a public or private key from the keyring.
811 kdata *km_findpub(const char *tag) { return (kh_find(&pub, tag, 1)); }
813 kdata *km_findpriv(const char *tag)
817 /* Unpleasantness for the sake of compatibility. */
818 if (!tag && (kd = kh_find(&priv, "tripe", 0)) != 0) return (kd);
819 else return (kh_find(&priv, tag ? tag : "tripe-dh", 1));
822 /* --- @km_tag@ --- *
824 * Arguments: @kdata *kd@ - pointer to the kdata object
826 * Returns: A pointer to the short tag by which the kdata was loaded.
829 const char *km_tag(kdata *kd) { return (SYM_NAME(kd->kn)); }
831 /* --- @km_ref@ --- *
833 * Arguments: @kdata *kd@ = pointer to the kdata object
837 * Use: Claim a new reference to a kdata object.
840 void km_ref(kdata *kd) { kd->ref++; }
842 /* --- @km_unref@ --- *
844 * Arguments: @kdata *kd@ = pointer to the kdata object
848 * Use: Releases a reference to a kdata object.
851 void km_unref(kdata *kd)
853 if (--kd->ref) return;
854 if (kd->kpriv) mp_drop(kd->kpriv);
855 G_DESTROY(kd->g, kd->kpub);
857 G_DESTROYGROUP(kd->g);
860 /*----- That's all, folks -------------------------------------------------*/