d28421fe977e555e3bff1d62b2f1752ad807c050
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 -------------------------------------------------*/