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
)
185 /* --- Symmetric encryption for bulk data --- */
187 if ((p
= key_getattr(kf
, k
, "cipher")) == 0) p
= "blowfish-cbc";
188 if ((a
->c
= gcipher_byname(p
)) == 0) {
189 a_format(e
, "unknown-cipher", "%s", p
, A_END
);
193 /* --- Hash function --- */
195 if ((p
= key_getattr(kf
, k
, "hash")) == 0) p
= "rmd160";
196 if ((a
->h
= ghash_byname(p
)) == 0) {
197 a_format(e
, "unknown-hash", "%s", p
, A_END
);
201 /* --- Symmetric encryption for key derivation --- */
203 if ((p
= key_getattr(kf
, k
, "mgf")) == 0) {
205 dstr_putf(&d
, "%s-mgf", a
->h
->name
);
208 if ((a
->mgf
= gcipher_byname(p
)) == 0) {
209 a_format(e
, "unknown-mgf-cipher", "%s", p
, A_END
);
213 /* --- Message authentication for bulk data --- */
215 if ((p
= key_getattr(kf
, k
, "mac")) != 0) {
218 if ((q
= strchr(d
.buf
, '/')) != 0)
220 if ((a
->m
= gmac_byname(d
.buf
)) == 0) {
221 a_format(e
, "unknown-mac", "%s", d
.buf
, A_END
);
225 a
->tagsz
= a
->m
->hashsz
;
227 unsigned long n
= strtoul(q
, &qq
, 0);
229 a_format(e
, "bad-tag-length-string", "%s", q
, A_END
);
232 if (n
%8 || n
/8 > a
->m
->hashsz
) {
233 a_format(e
, "bad-tag-length", "%lu", n
, A_END
);
240 dstr_putf(&d
, "%s-hmac", a
->h
->name
);
241 if ((a
->m
= gmac_byname(d
.buf
)) == 0) {
242 a_format(e
, "no-hmac-for-hash", "%s", a
->h
->name
, A_END
);
245 a
->tagsz
= a
->h
->hashsz
/2;
254 /* --- @algs_check@ --- *
256 * Arguments: @algswitch *a@ = a choice of algorithms
257 * @dstr *e@ = where to write error tokens
258 * @const group *g@ = the group we're working in
260 * Returns: Zero if OK; nonzero on error.
262 * Use: Checks an algorithm choice for sensibleness. This also
263 * derives some useful information from the choices, and you
264 * must call this before committing the algorithm selection
265 * for use by @keyset@ functions.
268 static int algs_check(algswitch
*a
, dstr
*e
, const group
*g
)
270 /* --- Derive the key sizes --- *
272 * Must ensure that we have non-empty keys. This isn't ideal, but it
273 * provides a handy sanity check. Also must be based on a 64- or 128-bit
274 * block cipher or we can't do the data expiry properly.
277 a
->hashsz
= a
->h
->hashsz
;
278 if ((a
->cksz
= keysz(a
->hashsz
, a
->c
->keysz
)) == 0) {
279 a_format(e
, "cipher", "%s", a
->c
->name
,
280 "no-key-size", "%lu", (unsigned long)a
->hashsz
,
284 if ((a
->mksz
= keysz(a
->hashsz
, a
->m
->keysz
)) == 0) {
285 a_format(e
, "mac", "%s", a
->m
->name
,
286 "no-key-size", "%lu", (unsigned long)a
->hashsz
,
291 /* --- Derive the data limit --- */
293 if (a
->c
->blksz
< 16) a
->expsz
= MEG(64);
294 else a
->expsz
= MEG(2048);
296 /* --- Ensure the MGF accepts hashes as keys --- */
298 if (keysz(a
->hashsz
, a
->mgf
->keysz
) != a
->hashsz
) {
299 a_format(e
, "mgf", "%s", a
->mgf
->name
,
300 "restrictive-key-schedule",
305 /* --- All ship-shape and Bristol-fashion --- */
310 /* --- @km_samealgsp@ --- *
312 * Arguments: @const kdata *kdx, *kdy@ = two key data objects
314 * Returns: Nonzero if their two algorithm selections are the same.
316 * Use: Checks sameness of algorithm selections: used to ensure that
317 * peers are using sensible algorithms.
320 int km_samealgsp(const kdata
*kdx
, const kdata
*kdy
)
322 const algswitch
*a
= &kdx
->algs
, *aa
= &kdy
->algs
;
324 return (group_samep(kdx
->g
, kdy
->g
) && a
->c
== aa
->c
&&
325 a
->mgf
== aa
->mgf
&& a
->h
== aa
->h
&&
326 a
->m
== aa
->m
&& a
->tagsz
== aa
->tagsz
);
329 /*----- Key data and key nodes --------------------------------------------*/
331 typedef struct keyhalf
{
333 int (*load
)(const kgops
*, key_data
*, kdata
*, dstr
*, dstr
*);
340 /* --- @kh_loadpub@, @kh_loadpriv@ --- *
342 * Arguments: @const kgops *ko@ = key-group operations for key type
343 * @key_data *d@ = key data object as stored in keyring
344 * @kdata *kd@ = our key-data object to fill in
345 * @dstr *t@ = the key tag name
346 * @dstr *e@ = a string to write error tokens to
348 * Returns: Zero on success, @-1@ on error.
350 * Use: These functions handle the main difference between public and
351 * private key halves. They are responsible for setting @g@,
352 * @kpriv@ and @kpub@ appropriately in all keys, handling the
353 * mismatch between the largely half-indifferent calling code
354 * and the group-specific loading functions.
356 * The function @kh_loadpriv@ is also responsible for checking
357 * the group for goodness. We don't bother checking public
358 * keys, because each public key we actually end up using must
359 * share a group with a private key which we'll already have
363 static int kh_loadpub(const kgops
*ko
, key_data
*d
, kdata
*kd
,
368 if ((rc
= ko
->loadpub(d
, kd
, t
, e
)) != 0)
370 if (group_check(kd
->g
, kd
->kpub
)) {
371 a_format(e
, "bad-public-group-element");
378 G_DESTROY(kd
->g
, kd
->kpub
);
379 G_DESTROYGROUP(kd
->g
);
384 static int kh_loadpriv(const kgops
*ko
, key_data
*d
, kdata
*kd
,
390 if ((rc
= ko
->loadpriv(d
, kd
, t
, e
)) != 0)
392 if ((err
= G_CHECK(kd
->g
, &rand_global
)) != 0) {
393 a_format(e
, "bad-group", "%s", err
, A_END
);
400 G_DESTROY(kd
->g
, kd
->kpub
);
401 G_DESTROYGROUP(kd
->g
);
406 static struct keyhalf
407 priv
= { "private", kh_loadpriv
},
408 pub
= { "public", kh_loadpub
};
410 /* --- @keymoan@ --- *
412 * Arguments: @const char *file@ = name of the file
413 * @int line@ = line number in file
414 * @const char *msg@ = error message
415 * @void *p@ = argument pointer (indicates which keyring)
419 * Use: Reports an error message about loading a key file.
422 static void keymoan(const char *file
, int line
, const char *msg
, void *p
)
427 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", file
,
428 "io-error", "?ERRNO", A_END
);
430 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", file
, "line", "%d", line
,
435 /* --- @kh_reopen@ --- *
437 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure
439 * Returns: Zero on success, @-1@ on error.
441 * Use: Reopens the key file for the appropriate key half. If this
442 * fails, everything is left as it was; if it succeeds, then the
443 * old file is closed (if it was non-null) and the new one put
447 static int kh_reopen(keyhalf
*kh
)
449 key_file
*kf
= CREATE(key_file
);
451 if (key_open(kf
, kh
->kr
, KOPEN_READ
, keymoan
, kh
)) {
452 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", kh
->kr
,
453 "io-error", "?ERRNO", A_END
);
466 /* --- @kh_init@ --- *
468 * Arguments: @keyhalf *kh@ = pointer to keyhalf structure to set up
469 * @const char *kr@ = name of the keyring file
473 * Use: Initialize a keyhalf structure, maintaining the private or
474 * public keys. Intended to be called during initialization:
475 * exits if there's some kind of problem.
478 static void kh_init(keyhalf
*kh
, const char *kr
)
481 fwatch_init(&kh
->w
, kr
);
482 sym_create(&kh
->tab
);
486 die(EXIT_FAILURE
, "failed to load %s keyring `%s'", kh
->kind
, kr
);
489 /* --- @kh_load@ --- *
491 * Arguments: @keyhalf *kh@ = pointer to keyhalf
492 * @const char *tag@ = key tag to be loaded
493 * @int complainp@ = whether to complain about missing keys
495 * Returns: Pointer to a @kdata@ structure if successful, or null on
498 * Use: Attempts to load a key from the current key file. This
499 * function always reads data from the file: it's used when
500 * there's a cache miss from @kh_find@, and when refreshing the
501 * known keys in @kh_refresh@. The returned kdata has a
502 * reference count of exactly 1, and has no home knode.
505 static kdata
*kh_load(keyhalf
*kh
, const char *tag
, int complainp
)
515 /* --- Find the key and grab its tag --- */
517 if (key_qtag(kh
->kf
, tag
, &t
, &k
, &d
)) {
519 a_warn("KEYMGMT", "%s-keyring", kh
->kind
, "%s", kh
->kr
,
520 "key-not-found", "%s", tag
, A_END
);
525 /* --- Find the key's group type and the appropriate operations --- *
527 * There are several places to look for the key type. The most obvious is
528 * the `kx-group' key attribute. But there's also the key type itself, for
529 * compatibility reasons.
532 ty
= key_getattr(kh
->kf
, k
, "kx-group");
533 if (!ty
&& strncmp(k
->type
, "tripe-", 6) == 0) ty
= k
->type
+ 6;
536 for (ko
= kgtab
; *ko
; ko
++)
537 if (strcmp((*ko
)->ty
, ty
) == 0) goto foundko
;
538 a_warn("KEYMGMT", "%s-keyring", kh
->kind
,
539 "%s", kh
->kr
, "key", "%s", t
.buf
,
540 "unknown-group-type", "%s", ty
, A_END
);
545 if (kh
->load(*ko
, *d
, kd
, &t
, &e
)) {
546 a_warn("KEYMGMT", "%s-keyring", kh
->kind
,
547 "%s", kh
->kr
, "key" "%s", t
.buf
,
548 "*%s", e
.buf
, A_END
);
552 if (algs_get(&kd
->algs
, &e
, kh
->kf
, k
) ||
553 (kd
->kpriv
&& algs_check(&kd
->algs
, &e
, kd
->g
))) {
554 a_warn("KEYMGMT", "%s-keyring", kh
->kind
,
555 "%s", kh
->kr
, "key", "%s", t
.buf
,
556 "*%s", e
.buf
, A_END
);
560 kd
->tag
= xstrdup(t
.buf
);
561 kd
->indexsz
= mp_octets(kd
->g
->r
);
566 IF_TRACING(T_KEYMGMT
, {
567 trace(T_KEYMGMT
, "keymgmt: loaded %s key `%s'", kh
->kind
, t
.buf
);
568 IF_TRACING(T_CRYPTO
, {
569 trace(T_CRYPTO
, "crypto: r = %s", mpstr(kd
->g
->r
));
570 trace(T_CRYPTO
, "crypto: h = %s", mpstr(kd
->g
->h
));
572 trace(T_CRYPTO
, "crypto: x = %s", mpstr(kd
->kpriv
));
573 trace(T_CRYPTO
, "crypto: cipher = %s", kd
->algs
.c
->name
);
574 trace(T_CRYPTO
, "crypto: mgf = %s", kd
->algs
.mgf
->name
);
575 trace(T_CRYPTO
, "crypto: hash = %s", kd
->algs
.h
->name
);
576 trace(T_CRYPTO
, "crypto: mac = %s/%lu",
577 kd
->algs
.m
->name
, (unsigned long)kd
->algs
.tagsz
* 8);
584 if (kd
->kpriv
) mp_drop(kd
->kpriv
);
585 G_DESTROY(kd
->g
, kd
->kpub
);
586 G_DESTROYGROUP(kd
->g
);
597 /* --- @kh_find@ --- *
599 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
600 * @const char *tag@ = key to be obtained
601 * @int complainp@ = whether to complain about missing keys
603 * Returns: A pointer to the kdata, or null on error.
605 * Use: Obtains kdata, maybe from the cache. This won't update a
606 * stale cache entry, though @kh_refresh@ ought to have done
607 * that already. The returned kdata object may be shared with
608 * other users. (One of this function's responsibilities, over
609 * @kh_load@, is to set the home knode of a freshly loaded
613 static kdata
*kh_find(keyhalf
*kh
, const char *tag
, int complainp
)
619 kn
= sym_find(&kh
->tab
, tag
, -1, sizeof(knode
), &f
);
622 if (kn
->f
& KNF_BROKEN
) {
624 trace(T_KEYMGMT
, "keymgmt: key `%s' marked as broken", tag
); )
630 T( trace(T_KEYMGMT
, "keymgmt: %scache hit for key `%s'",
631 kd ?
"" : "negative ", tag
); )
634 kd
= kh_load(kh
, tag
, complainp
);
648 /* --- @kh_refresh@ --- *
650 * Arguments: @keyhalf *kh@ = pointer to the keyhalf
652 * Returns: Zero if nothing needs to be done; nonzero if peers should
653 * refresh their keys.
655 * Use: Refreshes cached keys from files.
657 * Each active knode is examined to see if a new key is
658 * available: the return value is nonzero if any new keys are.
659 * A key is considered new if its algorithms, public key, or
660 * expiry time are/is different.
662 * Stub knodes (with no kdata attached) are removed, so that a
663 * later retry can succeed if the file has been fixed. (This
664 * doesn't count as a change, since no peers should be relying
665 * on a nonexistent key.)
668 static int kh_refresh(keyhalf
*kh
)
675 if (!fwatch_update(&kh
->w
, kh
->kr
) || kh_reopen(kh
))
678 T( trace(T_KEYMGMT
, "keymgmt: rescan %s keyring `%s'", kh
->kind
, kh
->kr
); )
679 for (sym_mkiter(&i
, &kh
->tab
); (kn
= sym_next(&i
)) != 0; ) {
681 T( trace(T_KEYMGMT
, "keymgmt: discard stub entry for key `%s'",
683 sym_remove(&kh
->tab
, kn
);
686 if ((kd
= kh_load(kh
, SYM_NAME(kn
), 1)) == 0) {
687 if (!(kn
->f
& KNF_BROKEN
)) {
688 T( trace(T_KEYMGMT
, "keymgmt: failed to load new key `%s': "
689 "marking it as broken",
695 kn
->f
&= ~KNF_BROKEN
;
696 if (kd
->t_exp
== kn
->kd
->t_exp
&&
697 km_samealgsp(kd
, kn
->kd
) &&
698 G_EQ(kd
->g
, kd
->kpub
, kn
->kd
->kpub
)) {
699 T( trace(T_KEYMGMT
, "keymgmt: key `%s' unchanged", SYM_NAME(kn
)); )
702 T( trace(T_KEYMGMT
, "keymgmt: loaded new version of key `%s'",
713 /*----- Main code ---------------------------------------------------------*/
715 const char *tag_priv
;
718 /* --- @km_init@ --- *
720 * Arguments: @const char *privkr@ = private keyring file
721 * @const char *pubkr@ = public keyring file
722 * @const char *ptag@ = default private-key tag
726 * Use: Initializes the key-management machinery, loading the
727 * keyrings and so on.
730 void km_init(const char *privkr
, const char *pubkr
, const char *ptag
)
732 const gchash
*const *hh
;
734 for (hh
= ghashtab
; *hh
; hh
++) {
735 if ((*hh
)->hashsz
> MAXHASHSZ
) {
736 die(EXIT_FAILURE
, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d",
737 (*hh
)->name
, (unsigned long)(*hh
)->hashsz
, MAXHASHSZ
);
741 kh_init(&priv
, privkr
);
742 kh_init(&pub
, pubkr
);
745 if ((master
= km_findpriv(ptag
)) == 0) exit(EXIT_FAILURE
);
748 /* --- @km_reload@ --- *
752 * Returns: Zero if OK, nonzero to force reloading of keys.
754 * Use: Checks the keyrings to see if they need reloading.
762 if (kh_refresh(&priv
)) {
771 if (kh_refresh(&pub
))
776 /* --- @km_findpub@, @km_findpriv@ --- *
778 * Arguments: @const char *tag@ = key tag to load
780 * Returns: Pointer to the kdata object if successful, or null on error.
782 * Use: Fetches a public or private key from the keyring.
785 kdata
*km_findpub(const char *tag
) { return (kh_find(&pub
, tag
, 1)); }
787 kdata
*km_findpriv(const char *tag
)
791 /* Unpleasantness for the sake of compatibility. */
792 if (!tag
&& (kd
= kh_find(&priv
, "tripe", 0)) != 0) return (kd
);
793 else return (kh_find(&priv
, tag ? tag
: "tripe-dh", 1));
796 /* --- @km_tag@ --- *
798 * Arguments: @kdata *kd@ - pointer to the kdata object
800 * Returns: A pointer to the short tag by which the kdata was loaded.
803 const char *km_tag(kdata
*kd
) { return (SYM_NAME(kd
->kn
)); }
805 /* --- @km_ref@ --- *
807 * Arguments: @kdata *kd@ = pointer to the kdata object
811 * Use: Claim a new reference to a kdata object.
814 void km_ref(kdata
*kd
) { kd
->ref
++; }
816 /* --- @km_unref@ --- *
818 * Arguments: @kdata *kd@ = pointer to the kdata object
822 * Use: Releases a reference to a kdata object.
825 void km_unref(kdata
*kd
)
827 if (--kd
->ref
) return;
828 if (kd
->kpriv
) mp_drop(kd
->kpriv
);
829 G_DESTROY(kd
->g
, kd
->kpub
);
831 G_DESTROYGROUP(kd
->g
);
834 /*----- That's all, folks -------------------------------------------------*/