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 /*----- Global variables --------------------------------------------------*/
39 /*----- Static variables --------------------------------------------------*/
41 static key_file
*kf_pub
;
42 static const char *kr_priv
, *kr_pub
, *tag_priv
;
43 static fwatch w_priv
, w_pub
;
45 /*----- Key groups --------------------------------------------------------*/
47 typedef struct kgops
{
49 int (*loadpriv
)(key_data
*, group
**, mp
**, dstr
*, dstr
*);
50 int (*loadpub
)(key_data
*, group
**, ge
**, dstr
*, dstr
*);
53 /* --- Diffie-Hellman --- */
55 static int kgdh_priv(key_data
*kd
, group
**g
, mp
**x
, dstr
*t
, dstr
*e
)
57 key_packstruct kps
[DH_PRIVFETCHSZ
];
62 kp
= key_fetchinit(dh_privfetch
, kps
, &dp
);
63 if ((rc
= key_unpack(kp
, kd
, t
)) != 0) {
64 a_format(e
, "unpack-failed", "%s", key_strerror(rc
), A_END
);
67 *g
= group_prime(&dp
.dp
);
78 static int kgdh_pub(key_data
*kd
, group
**g
, ge
**p
, dstr
*t
, dstr
*e
)
80 key_packstruct kps
[DH_PUBFETCHSZ
];
85 kp
= key_fetchinit(dh_pubfetch
, kps
, &dp
);
86 if ((rc
= key_unpack(kp
, kd
, t
)) != 0) {
87 a_format(e
, "unpack-failed", "%s", key_strerror(rc
), A_END
);
90 *g
= group_prime(&dp
.dp
);
92 if (G_FROMINT(*g
, *p
, dp
.y
)) {
93 a_format(e
, "bad-public-vector", A_END
);
108 static const kgops kgdh_ops
= { "dh", kgdh_priv
, kgdh_pub
};
110 /* --- Elliptic curve --- */
112 static int kgec_priv(key_data
*kd
, group
**g
, mp
**x
, dstr
*t
, dstr
*e
)
114 key_packstruct kps
[EC_PRIVFETCHSZ
];
121 kp
= key_fetchinit(ec_privfetch
, kps
, &ep
);
122 if ((rc
= key_unpack(kp
, kd
, t
)) != 0) {
123 a_format(e
, "unpack-failed", "%s", key_strerror(rc
), A_END
);
126 if ((err
= ec_getinfo(&ei
, ep
.cstr
)) != 0) {
127 a_format(e
, "decode-failed", "%s", err
, A_END
);
141 static int kgec_pub(key_data
*kd
, group
**g
, ge
**p
, dstr
*t
, dstr
*e
)
143 key_packstruct kps
[EC_PUBFETCHSZ
];
150 kp
= key_fetchinit(ec_pubfetch
, kps
, &ep
);
151 if ((rc
= key_unpack(kp
, kd
, t
)) != 0) {
152 a_format(e
, "unpack-failed", "%s", key_strerror(rc
), A_END
);
155 if ((err
= ec_getinfo(&ei
, ep
.cstr
)) != 0) {
156 a_format(e
, "decode-failed", "%s", err
, A_END
);
161 if (G_FROMEC(*g
, *p
, &ep
.p
)) {
162 a_format(e
, "bad-public-vector", A_END
);
177 static const kgops kgec_ops
= { "ec", kgec_priv
, kgec_pub
};
179 /* --- Table of supported key types --- */
181 static const kgops
*kgtab
[] = { &kgdh_ops
, &kgec_ops
, 0 };
183 /*----- Algswitch stuff ---------------------------------------------------*/
185 /* --- @algs_get@ --- *
187 * Arguments: @algswitch *a@ = where to put the algorithms
188 * @dstr *e@ = where to write errror tokens
189 * @key_file *kf@ = key file
190 * @key *k@ = key to inspect
192 * Returns: Zero if OK; nonzero on error.
194 * Use: Extracts an algorithm choice from a key.
197 static int algs_get(algswitch
*a
, dstr
*e
, key_file
*kf
, key
*k
)
204 /* --- Symmetric encryption for bulk data --- */
206 if ((p
= key_getattr(kf
, k
, "cipher")) == 0) p
= "blowfish-cbc";
207 if ((a
->c
= gcipher_byname(p
)) == 0) {
208 a_format(e
, "unknown-cipher", "%s", p
, A_END
);
212 /* --- Hash function --- */
214 if ((p
= key_getattr(kf
, k
, "hash")) == 0) p
= "rmd160";
215 if ((a
->h
= ghash_byname(p
)) == 0) {
216 a_format(e
, "unknown-hash", "%s", p
, A_END
);
220 /* --- Symmetric encryption for key derivation --- */
222 if ((p
= key_getattr(kf
, k
, "mgf")) == 0) {
224 dstr_putf(&d
, "%s-mgf", a
->h
->name
);
227 if ((a
->mgf
= gcipher_byname(p
)) == 0) {
228 a_format(e
, "unknown-mgf-cipher", "%s", p
, A_END
);
232 /* --- Message authentication for bulk data --- */
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;
273 /* --- @algs_check@ --- *
275 * Arguments: @algswitch *a@ = a choice of algorithms
276 * @dstr *e@ = where to write error tokens
277 * @const group *g@ = the group we're working in
279 * Returns: Zero if OK; nonzero on error.
281 * Use: Checks an algorithm choice for sensibleness. This also
282 * derives some useful information from the choices, and you
283 * must call this before committing the algorithm selection
284 * for use by @keyset@ functions.
287 static int algs_check(algswitch
*a
, dstr
*e
, const group
*g
)
289 /* --- Derive the key sizes --- *
291 * Must ensure that we have non-empty keys. This isn't ideal, but it
292 * provides a handy sanity check. Also must be based on a 64- or 128-bit
293 * block cipher or we can't do the data expiry properly.
296 a
->hashsz
= a
->h
->hashsz
;
297 if ((a
->cksz
= keysz(a
->hashsz
, a
->c
->keysz
)) == 0) {
298 a_format(e
, "cipher", "%s", a
->c
->name
,
299 "no-key-size", "%lu", (unsigned long)a
->hashsz
,
303 if ((a
->mksz
= keysz(a
->hashsz
, a
->m
->keysz
)) == 0) {
304 a_format(e
, "mac", "%s", a
->m
->name
,
305 "no-key-size", "%lu", (unsigned long)a
->hashsz
,
310 /* --- Derive the data limit --- */
312 if (a
->c
->blksz
< 16) a
->expsz
= MEG(64);
313 else a
->expsz
= MEG(2048);
315 /* --- Ensure the MGF accepts hashes as keys --- */
317 if (keysz(a
->hashsz
, a
->mgf
->keysz
) != a
->hashsz
) {
318 a_format(e
, "mgf", "%s", a
->mgf
->name
,
319 "restrictive-key-schedule",
324 /* --- All ship-shape and Bristol-fashion --- */
329 /* --- @algs_samep@ --- *
331 * Arguments: @const algswitch *a, *aa@ = two algorithm selections
333 * Returns: Nonzero if the two selections are the same.
335 * Use: Checks sameness of algorithm selections: used to ensure that
336 * peers are using sensible algorithms.
339 static int algs_samep(const algswitch
*a
, const algswitch
*aa
)
341 return (a
->c
== aa
->c
&& a
->mgf
== aa
->mgf
&& a
->h
== aa
->h
&&
342 a
->m
== aa
->m
&& a
->tagsz
== aa
->tagsz
);
345 /*----- Main code ---------------------------------------------------------*/
347 /* --- @keymoan@ --- *
349 * Arguments: @const char *file@ = name of the file
350 * @int line@ = line number in file
351 * @const char *msg@ = error message
352 * @void *p@ = argument pointer (indicates which keyring)
356 * Use: Reports an error message about loading a key file.
359 static void keymoan(const char *file
, int line
, const char *msg
, void *p
)
361 const char *kind
= p
;
364 a_warn("KEYMGMT", "%s-keyring", kind
, "%s", file
,
365 "io-error", "?ERRNO", A_END
);
367 a_warn("KEYMGMT", "%s-keyring", kind
, "%s", file
, "line", "%d", line
,
374 * Arguments: @key_file *kf@ = pointer to key file
375 * @key *k@ = pointer to key
376 * @const char **tyr@ = where to put the type string
378 * Returns: Pointer to indicated key-group options, or null.
380 * Use: Looks up a key's group indicator and tries to find a matching
384 static const kgops
*keykg(key_file
*kf
, key
*k
, const char **tyr
)
389 /* --- Look up the key type in the table --- *
391 * There are several places to look for this. The most obvious is the
392 * `kx-group' key attribute. But there's also the key type itself.
395 ty
= key_getattr(kf
, k
, "kx-group");
396 if (!ty
&& strncmp(k
->type
, "tripe-", 6) == 0) ty
= k
->type
+ 6;
400 for (ko
= kgtab
; *ko
; ko
++) {
401 if (strcmp((*ko
)->ty
, ty
) == 0)
407 /* --- @loadpriv@ --- *
409 * Arguments: @dstr *d@ = string to write errors in
411 * Returns: Zero if OK, nonzero on error.
413 * Use: Loads the private key from its keyfile.
416 static int loadpriv(void)
427 const char *err
, *tag
, *ty
;
430 /* --- Open the private key file --- */
432 if (key_open(&kf
, kr_priv
, KOPEN_READ
, keymoan
, "private"))
435 /* --- Find the private key --- */
438 key_qtag(&kf
, tag
= tag_priv
, &t
, &k
, &kd
) :
439 key_qtag(&kf
, tag
= "tripe", &t
, &k
, &kd
) &&
440 key_qtag(&kf
, tag
= "tripe-dh", &t
, &k
, &kd
)) {
441 a_warn("KEYMGMT", "private-keyring", "%s", kr_priv
,
442 "key-not-found", "%s", tag
, A_END
);
446 /* --- Look up the key type in the table --- */
448 if ((ko
= keykg(&kf
, k
, &ty
)) == 0) {
449 a_warn("KEYMGMT", "private-keyring",
450 "%s", kr_priv
, "key", "%s", t
.buf
,
451 "unknown-group-type", "%s", ty
, A_END
);
455 /* --- Load the key --- */
457 if (ko
->loadpriv(*kd
, &g
, &x
, &t
, &e
)) {
458 a_warn("KEYMGMT", "private-keyring",
459 "%s", kr_priv
, "key", "%s", t
.buf
,
460 "*%s", e
.buf
, A_END
);
464 /* --- Check that the key is sensible --- */
466 if ((err
= G_CHECK(g
, &rand_global
)) != 0) {
467 a_warn("KEYMGMT", "private-keyring",
468 "%s", kr_priv
, "key", "%s", t
.buf
,
469 "bad-group", "%s", err
, A_END
);
473 /* --- Collect the algorithms --- */
475 if (algs_get(&a
, &e
, &kf
, k
) ||
476 algs_check(&a
, &e
, g
)) {
477 a_warn("KEYMGMT", "private-keyring",
478 "%s", kr_priv
, "key", "%s", t
.buf
,
479 "*%s", e
.buf
, A_END
);
483 /* --- Good, we're happy --- *
485 * Dodginess! We change the group over here, but don't free any old group
486 * elements. This assumes that the new group is basically the same as the
487 * old one, and will happily adopt the existing elements. If it isn't,
488 * then we lose badly. Check this, then.
492 if (!group_samep(g
, gg
)) {
493 a_warn("KEYMGMT", "private-keyring",
494 "%s", kr_priv
, "key", "%s", t
.buf
,
495 "changed-group", A_END
);
506 G_EXP(g
, kpub
, g
->g
, x
);
507 indexsz
= mp_octets(g
->r
);
509 /* --- Dump out the group --- */
511 IF_TRACING(T_KEYMGMT
, {
512 trace(T_KEYMGMT
, "keymgmt: extracted private key `%s'", t
.buf
);
513 IF_TRACING(T_CRYPTO
, {
514 trace(T_CRYPTO
, "crypto: r = %s", mpstr(g
->r
));
515 trace(T_CRYPTO
, "crypto: h = %s", mpstr(g
->h
));
516 trace(T_CRYPTO
, "crypto: x = %s", mpstr(x
));
517 trace(T_CRYPTO
, "crypto: cipher = %s", a
.c
->name
);
518 trace(T_CRYPTO
, "crypto: mgf = %s", a
.mgf
->name
);
519 trace(T_CRYPTO
, "crypto: hash = %s", a
.h
->name
);
520 trace(T_CRYPTO
, "crypto: mac = %s/%lu",
521 a
.m
->name
, (unsigned long)a
.tagsz
* 8);
525 /* --- Success! --- */
532 /* --- Tidy up --- */
540 if (g
) G_DESTROYGROUP(g
);
544 /* --- @loadpub@ --- *
546 * Arguments: @dstr *d@ = string to write errors to
548 * Returns: Zero if OK, nonzero on error.
550 * Use: Reloads the public keyring.
553 static int loadpub(void)
555 key_file
*kf
= CREATE(key_file
);
557 if (key_open(kf
, kr_pub
, KOPEN_READ
, keymoan
, "public")) {
562 T( trace(T_KEYMGMT
, "keymgmt: loaded public keyring `%s'", kr_pub
); )
566 /* --- @km_reload@ --- *
570 * Returns: Zero if OK, nonzero to force reloading of keys.
572 * Use: Checks the keyrings to see if they need reloading.
580 /* --- Check the private key first --- */
582 if (fwatch_update(&w_priv
, kr_priv
)) {
583 T( trace(T_KEYMGMT
, "keymgmt: private keyring updated: reloading..."); )
588 /* --- Now check the public keys --- */
590 if (fwatch_update(&w_pub
, kr_pub
)) {
591 T( trace(T_KEYMGMT
, "keymgmt: public keyring updated: reloading..."); )
605 /* --- @km_init@ --- *
607 * Arguments: @const char *priv@ = private keyring file
608 * @const char *pub@ = public keyring file
609 * @const char *tag@ = tag to load
613 * Use: Initializes, and loads the private key.
616 void km_init(const char *priv
, const char *pub
, const char *tag
)
618 const gchash
*const *hh
;
623 fwatch_init(&w_priv
, kr_priv
);
624 fwatch_init(&w_pub
, kr_pub
);
626 for (hh
= ghashtab
; *hh
; hh
++) {
627 if ((*hh
)->hashsz
> MAXHASHSZ
) {
628 die(EXIT_FAILURE
, "INTERNAL ERROR: %s hash length %lu > MAXHASHSZ %d",
629 (*hh
)->name
, (unsigned long)(*hh
)->hashsz
, MAXHASHSZ
);
633 if (loadpriv() || loadpub())
637 /* --- @km_getpubkey@ --- *
639 * Arguments: @const char *tag@ = public key tag to load
640 * @ge *kpub@ = where to put the public key
641 * @time_t *t_exp@ = where to put the expiry time
643 * Returns: Zero if OK, nonzero if it failed.
645 * Use: Fetches a public key from the keyring.
648 int km_getpubkey(const char *tag
, ge
*kpub
, time_t *t_exp
)
661 /* --- Find the key --- */
663 if (key_qtag(kf_pub
, tag
, &t
, &k
, &kd
)) {
664 a_warn("KEYMGMT", "public-keyring", "%s", kr_pub
,
665 "key-not-found", "%s", tag
, A_END
);
669 /* --- Look up the key type in the table --- */
671 if ((ko
= keykg(kf_pub
, k
, &ty
)) == 0) {
672 a_warn("KEYMGMT", "public-keyring",
673 "%s", kr_pub
, "key", "%s", t
.buf
,
674 "unknown-group-type", "%s", ty
, A_END
);
678 /* --- Load the key --- */
680 if (ko
->loadpub(*kd
, &g
, &p
, &t
, &e
)) {
681 a_warn("KEYMGMT", "public-keyring",
682 "%s", kr_pub
, "key", "%s", t
.buf
,
683 "*%s", e
.buf
, A_END
);
687 /* --- Ensure that the group is correct --- *
689 * Dodginess! We assume that if this works, our global group is willing to
690 * adopt this public element. Probably reasonable.
693 if (!group_samep(gg
, g
)) {
694 a_warn("KEYMGMT", "public-keyring",
695 "%s", kr_pub
, "key", "%s", t
.buf
,
696 "*%s", e
.buf
, A_END
);
700 /* --- Check the public group element --- */
702 if (group_check(gg
, p
)) {
703 a_warn("KEYMGMT", "public-keyring",
704 "%s", kr_pub
, "key", "%s", t
.buf
,
705 "bad-public-group-element",
710 /* --- Check the algorithms --- */
712 if (algs_get(&a
, &e
, kf_pub
, k
)) {
713 a_warn("KEYMGMT", "public-keyring",
714 "%s", kr_pub
, "key", "%s", t
.buf
,
715 "*%s", e
.buf
, A_END
);
718 if (!algs_samep(&a
, &algs
)) {
719 a_warn("KEYMGMT", "public-keyring",
720 "%s", kr_pub
, "key", "%s", t
.buf
,
721 "algorithm-mismatch", A_END
);
725 /* --- Dump the public key --- */
727 IF_TRACING(T_KEYMGMT
, {
728 trace(T_KEYMGMT
, "keymgmt: extracted public key `%s'", t
.buf
);
729 trace(T_CRYPTO
, "crypto: p = %s", gestr(gg
, p
));
732 /* --- OK, accept the public key --- */
738 /* --- Tidy up --- */
741 if (p
) G_DESTROY(g
, p
);
742 if (g
) G_DESTROYGROUP(g
);
748 /*----- That's all, folks -------------------------------------------------*/