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 error 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
)
182 dstr d
= DSTR_INIT
, dd
= DSTR_INIT
;
185 /* --- Hash function --- */
187 if ((p
= key_getattr(kf
, k
, "hash")) == 0) p
= "rmd160";
188 if ((a
->h
= ghash_byname(p
)) == 0) {
189 a_format(e
, "unknown-hash", "%s", p
, A_END
);
193 /* --- Symmetric encryption for key derivation --- */
195 if ((p
= key_getattr(kf
, k
, "mgf")) == 0) {
197 dstr_putf(&d
, "%s-mgf", a
->h
->name
);
200 if ((a
->mgf
= gcipher_byname(p
)) == 0) {
201 a_format(e
, "unknown-mgf-cipher", "%s", p
, A_END
);
205 /* --- Bulk crypto transform --- */
207 if ((p
= key_getattr(kf
, k
, "bulk")) == 0) p
= "v0";
208 for (bops
= bulktab
; bops
->name
&& strcmp(p
, bops
->name
) != 0; bops
++);
210 a_format(e
, "unknown-bulk-transform", "%s", p
, A_END
);
213 if ((a
->bulk
= bops
->getalgs(a
, e
, kf
, k
)) == 0) goto done
;
216 /* --- All done --- */
225 /* --- @algs_check@ --- *
227 * Arguments: @algswitch *a@ = a choice of algorithms
228 * @dstr *e@ = where to write error tokens
229 * @const group *g@ = the group we're working in
231 * Returns: Zero if OK; nonzero on error.
233 * Use: Checks an algorithm choice for sensibleness. This also
234 * derives some useful information from the choices, and you
235 * must call this before committing the algorithm selection
236 * for use by @keyset@ functions.
239 static int algs_check(algswitch
*a
, dstr
*e
, const group
*g
)
241 a
->hashsz
= a
->h
->hashsz
;
243 if (keysz(a
->hashsz
, a
->mgf
->keysz
) != a
->hashsz
) {
244 a_format(e
, "mgf", "%s", a
->mgf
->name
,
245 "restrictive-key-schedule",
250 if (a
->bulk
->ops
->checkalgs(a
->bulk
, a
, e
)) return (-1);
255 /* --- @km_samealgsp@ --- *
257 * Arguments: @const kdata *kdx, *kdy@ = two key data objects
259 * Returns: Nonzero if their two algorithm selections are the same.
261 * Use: Checks sameness of algorithm selections: used to ensure that
262 * peers are using sensible algorithms.
265 int km_samealgsp(const kdata
*kdx
, const kdata
*kdy
)
267 const algswitch
*a
= &kdx
->algs
, *aa
= &kdy
->algs
;
269 return (group_samep(kdx
->g
, kdy
->g
) &&
270 a
->mgf
== aa
->mgf
&& a
->h
== aa
->h
&&
271 a
->bulk
->ops
== aa
->bulk
->ops
&&
272 a
->bulk
->ops
->samealgsp(a
->bulk
, aa
->bulk
));
275 /*----- Key data and key nodes --------------------------------------------*/
277 typedef struct keyhalf
{
279 int (*load
)(const kgops
*, key_data
*, kdata
*, dstr
*, dstr
*);
286 /* --- @kh_loadpub@, @kh_loadpriv@ --- *
288 * Arguments: @const kgops *ko@ = key-group operations for key type
289 * @key_data *d@ = key data object as stored in keyring
290 * @kdata *kd@ = our key-data object to fill in
291 * @dstr *t@ = the key tag name
292 * @dstr *e@ = a string to write error tokens to
294 * Returns: Zero on success, @-1@ on error.
296 * Use: These functions handle the main difference between public and
297 * private key halves. They are responsible for setting @g@,
298 * @kpriv@ and @kpub@ appropriately in all keys, handling the
299 * mismatch between the largely half-indifferent calling code
300 * and the group-specific loading functions.
302 * The function @kh_loadpriv@ is also responsible for checking
303 * the group for goodness. We don't bother checking public
304 * keys, because each public key we actually end up using must
305 * share a group with a private key which we'll already have
309 static int kh_loadpub(const kgops
*ko
, key_data
*d
, kdata
*kd
,
314 if ((rc
= ko
->loadpub(d
, kd
, t
, e
)) != 0)
316 if (group_check(kd
->g
, kd
->kpub
)) {
317 a_format(e
, "bad-public-group-element", A_END
);
324 G_DESTROY(kd
->g
, kd
->kpub
);
325 G_DESTROYGROUP(kd
->g
);
330 static int kh_loadpriv(const kgops
*ko
, key_data
*d
, kdata
*kd
,
336 if ((rc
= ko
->loadpriv(d
, kd
, t
, e
)) != 0)
338 if ((err
= G_CHECK(kd
->g
, &rand_global
)) != 0) {
339 a_format(e
, "bad-group", "%s", err
, A_END
);
346 G_DESTROY(kd
->g
, kd
->kpub
);
347 G_DESTROYGROUP(kd
->g
);
352 static struct keyhalf
353 priv
= { "private", kh_loadpriv
},
354 pub
= { "public", kh_loadpub
};
356 /* --- @keymoan@ --- *
358 * Arguments: @const char *file@ = name of the file
359 * @int line@ = line number in file
360 * @const char *msg@ = error message
361 * @void *p@ = argument pointer (indicates which keyring)
365 * Use: Reports an error message about loading a key file.
368 static void keymoan(const char *file
, int line
, const char *msg
, void *p
)
373 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", file
,
374 "io-error", "?ERRNO", A_END
);
376 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", file
, "line", "%d", line
,
381 /* --- @kh_reopen@ --- *
383 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure
385 * Returns: Zero on success, @-1@ on error.
387 * Use: Reopens the key file for the appropriate key half. If this
388 * fails, everything is left as it was; if it succeeds, then the
389 * old file is closed (if it was non-null) and the new one put
393 static int kh_reopen(keyhalf
*kh
)
395 key_file
*kf
= CREATE(key_file
);
397 if (key_open(kf
, kh
->kr
, KOPEN_READ
, keymoan
, kh
)) {
398 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", kh
->kr
,
399 "io-error", "?ERRNO", A_END
);
412 /* --- @kh_init@ --- *
414 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure to set up
415 * @const char *kr@ = name of the keyring file
419 * Use: Initialize a keyhalf structure, maintaining the private or
420 * public keys. Intended to be called during initialization:
421 * exits if there's some kind of problem.
424 static void kh_init(keyhalf
*kh
, const char *kr
)
427 fwatch_init(&kh
->w
, kr
);
428 sym_create(&kh
->tab
);
432 die(EXIT_FAILURE
, "failed to load %s keyring `%s'", kh
->kind
, kr
);
435 /* --- @kh_load@ --- *
437 * Arguments: @keyhalf *kh@ = pointer to keyhalf
438 * @const char *tag@ = key tag to be loaded
439 * @int complainp@ = whether to complain about missing keys
441 * Returns: Pointer to a @kdata@ structure if successful, or null on
444 * Use: Attempts to load a key from the current key file. This
445 * function always reads data from the file: it's used when
446 * there's a cache miss from @kh_find@, and when refreshing the
447 * known keys in @kh_refresh@. The returned kdata has a
448 * reference count of exactly 1, and has no home knode.
451 static kdata
*kh_load(keyhalf
*kh
, const char *tag
, int complainp
)
461 /* --- Find the key and grab its tag --- */
463 if (key_qtag(kh
->kf
, tag
, &t
, &k
, &d
)) {
465 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", kh
->kr
,
466 "key-not-found", "%s", tag
, A_END
);
471 /* --- Find the key's group type and the appropriate operations --- *
473 * There are several places to look for the key type. The most obvious is
474 * the `kx-group' key attribute. But there's also the key type itself, for
475 * compatibility reasons.
478 ty
= key_getattr(kh
->kf
, k
, "kx-group");
479 if (!ty
&& strncmp(k
->type
, "tripe-", 6) == 0) ty
= k
->type
+ 6;
482 for (ko
= kgtab
; *ko
; ko
++)
483 if (strcmp((*ko
)->ty
, ty
) == 0) goto foundko
;
484 a_warn("KEYMGMT", "%s-keyring", kh
->kind
,
485 "%s", kh
->kr
, "key", "%s", t
.buf
,
486 "unknown-group-type", "%s", ty
, A_END
);
491 if (kh
->load(*ko
, *d
, kd
, &t
, &e
)) {
492 a_warn("KEYMGMT", "%s-keyring", kh
->kind
,
493 "%s", kh
->kr
, "key", "%s", t
.buf
,
494 "*%s", e
.buf
, A_END
);
498 if (algs_get(&kd
->algs
, &e
, kh
->kf
, k
) ||
499 (kd
->kpriv
&& algs_check(&kd
->algs
, &e
, kd
->g
))) {
500 a_warn("KEYMGMT", "%s-keyring", kh
->kind
,
501 "%s", kh
->kr
, "key", "%s", t
.buf
,
502 "*%s", e
.buf
, A_END
);
506 kd
->tag
= xstrdup(t
.buf
);
507 kd
->indexsz
= mp_octets(kd
->g
->r
);
512 IF_TRACING(T_KEYMGMT
, {
513 trace(T_KEYMGMT
, "keymgmt: loaded %s key `%s'", kh
->kind
, t
.buf
);
514 IF_TRACING(T_CRYPTO
, {
515 trace(T_CRYPTO
, "crypto: r = %s", mpstr(kd
->g
->r
));
516 trace(T_CRYPTO
, "crypto: h = %s", mpstr(kd
->g
->h
));
518 trace(T_CRYPTO
, "crypto: x = %s", mpstr(kd
->kpriv
));
519 kd
->algs
.bulk
->ops
->tracealgs(kd
->algs
.bulk
);
526 if (kd
->kpriv
) mp_drop(kd
->kpriv
);
527 G_DESTROY(kd
->g
, kd
->kpub
);
528 G_DESTROYGROUP(kd
->g
);
539 /* --- @kh_find@ --- *
541 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
542 * @const char *tag@ = key to be obtained
543 * @int complainp@ = whether to complain about missing keys
545 * Returns: A pointer to the kdata, or null on error.
547 * Use: Obtains kdata, maybe from the cache. This won't update a
548 * stale cache entry, though @kh_refresh@ ought to have done
549 * that already. The returned kdata object may be shared with
550 * other users. (One of this function's responsibilities, over
551 * @kh_load@, is to set the home knode of a freshly loaded
555 static kdata
*kh_find(keyhalf
*kh
, const char *tag
, int complainp
)
561 kn
= sym_find(&kh
->tab
, tag
, -1, sizeof(knode
), &f
);
564 if (kn
->f
& KNF_BROKEN
) {
566 trace(T_KEYMGMT
, "keymgmt: key `%s' marked as broken", tag
); )
572 T( trace(T_KEYMGMT
, "keymgmt: %scache hit for key `%s'",
573 kd ?
"" : "negative ", tag
); )
576 kd
= kh_load(kh
, tag
, complainp
);
590 /* --- @kh_refresh@ --- *
592 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
594 * Returns: Zero if nothing needs to be done; nonzero if peers should
595 * refresh their keys.
597 * Use: Refreshes cached keys from files.
599 * Each active knode is examined to see if a new key is
600 * available: the return value is nonzero if any new keys are.
601 * A key is considered new if its algorithms, public key, or
602 * expiry time are/is different.
604 * Stub knodes (with no kdata attached) are removed, so that a
605 * later retry can succeed if the file has been fixed. (This
606 * doesn't count as a change, since no peers should be relying
607 * on a nonexistent key.)
610 static int kh_refresh(keyhalf
*kh
)
617 if (!fwatch_update(&kh
->w
, kh
->kr
) || kh_reopen(kh
))
620 T( trace(T_KEYMGMT
, "keymgmt: rescan %s keyring `%s'", kh
->kind
, kh
->kr
); )
621 for (sym_mkiter(&i
, &kh
->tab
); (kn
= sym_next(&i
)) != 0; ) {
623 T( trace(T_KEYMGMT
, "keymgmt: discard stub entry for key `%s'",
625 sym_remove(&kh
->tab
, kn
);
628 if ((kd
= kh_load(kh
, SYM_NAME(kn
), 1)) == 0) {
629 if (!(kn
->f
& KNF_BROKEN
)) {
630 T( trace(T_KEYMGMT
, "keymgmt: failed to load new key `%s': "
631 "marking it as broken",
637 kn
->f
&= ~KNF_BROKEN
;
638 if (kd
->t_exp
== kn
->kd
->t_exp
&&
639 km_samealgsp(kd
, kn
->kd
) &&
640 G_EQ(kd
->g
, kd
->kpub
, kn
->kd
->kpub
)) {
641 T( trace(T_KEYMGMT
, "keymgmt: key `%s' unchanged", SYM_NAME(kn
)); )
644 T( trace(T_KEYMGMT
, "keymgmt: loaded new version of key `%s'",
655 /*----- Main code ---------------------------------------------------------*/
657 const char *tag_priv
;
660 /* --- @km_init@ --- *
662 * Arguments: @const char *privkr@ = private keyring file
663 * @const char *pubkr@ = public keyring file
664 * @const char *ptag@ = default private-key tag
668 * Use: Initializes the key-management machinery, loading the
669 * keyrings and so on.
672 void km_init(const char *privkr
, const char *pubkr
, const char *ptag
)
674 const gchash
*const *hh
;
676 for (hh
= ghashtab
; *hh
; hh
++) {
677 if ((*hh
)->hashsz
> MAXHASHSZ
) {
678 die(EXIT_FAILURE
, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d",
679 (*hh
)->name
, (unsigned long)(*hh
)->hashsz
, MAXHASHSZ
);
683 kh_init(&priv
, privkr
);
684 kh_init(&pub
, pubkr
);
687 if ((master
= km_findpriv(ptag
)) == 0) exit(EXIT_FAILURE
);
690 /* --- @km_reload@ --- *
694 * Returns: Zero if OK, nonzero to force reloading of keys.
696 * Use: Checks the keyrings to see if they need reloading.
704 if (kh_refresh(&priv
)) {
713 if (kh_refresh(&pub
))
718 /* --- @km_findpub@, @km_findpriv@ --- *
720 * Arguments: @const char *tag@ = key tag to load
722 * Returns: Pointer to the kdata object if successful, or null on error.
724 * Use: Fetches a public or private key from the keyring.
727 kdata
*km_findpub(const char *tag
) { return (kh_find(&pub
, tag
, 1)); }
729 kdata
*km_findpriv(const char *tag
)
733 /* Unpleasantness for the sake of compatibility. */
734 if (!tag
&& (kd
= kh_find(&priv
, "tripe", 0)) != 0) return (kd
);
735 else return (kh_find(&priv
, tag ? tag
: "tripe-dh", 1));
738 /* --- @km_tag@ --- *
740 * Arguments: @kdata *kd@ - pointer to the kdata object
742 * Returns: A pointer to the short tag by which the kdata was loaded.
745 const char *km_tag(kdata
*kd
) { return (SYM_NAME(kd
->kn
)); }
747 /* --- @km_ref@ --- *
749 * Arguments: @kdata *kd@ = pointer to the kdata object
753 * Use: Claim a new reference to a kdata object.
756 void km_ref(kdata
*kd
) { kd
->ref
++; }
758 /* --- @km_unref@ --- *
760 * Arguments: @kdata *kd@ = pointer to the kdata object
764 * Use: Releases a reference to a kdata object.
767 void km_unref(kdata
*kd
)
769 if (--kd
->ref
) return;
770 if (kd
->kpriv
) mp_drop(kd
->kpriv
);
771 G_DESTROY(kd
->g
, kd
->kpub
);
773 G_DESTROYGROUP(kd
->g
);
777 /*----- That's all, folks -------------------------------------------------*/