Commit | Line | Data |
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5c3f75ec | 1 | /* -*-c-*- |
5c3f75ec | 2 | * |
3 | * Catcrypt key-encapsulation | |
4 | * | |
5 | * (c) 2004 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
5c3f75ec | 9 | * |
10 | * This file is part of Catacomb. | |
11 | * | |
12 | * Catacomb is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU Library General Public License as | |
14 | * published by the Free Software Foundation; either version 2 of the | |
15 | * License, or (at your option) any later version. | |
45c0fd36 | 16 | * |
5c3f75ec | 17 | * Catacomb 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 Library General Public License for more details. | |
45c0fd36 | 21 | * |
5c3f75ec | 22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free | |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, | |
25 | * MA 02111-1307, USA. | |
26 | */ | |
27 | ||
28 | /*----- Header files ------------------------------------------------------*/ | |
29 | ||
cd6eca43 MW |
30 | #define _FILE_OFFSET_BITS 64 |
31 | ||
5c3f75ec | 32 | #include <stdlib.h> |
33 | ||
34 | #include <mLib/alloc.h> | |
35 | #include <mLib/dstr.h> | |
36 | #include <mLib/report.h> | |
37 | #include <mLib/sub.h> | |
38 | ||
39 | #include "mprand.h" | |
40 | #include "rand.h" | |
41 | ||
42 | #include "ec.h" | |
43 | #include "ec-keys.h" | |
44 | #include "dh.h" | |
45 | #include "rsa.h" | |
fc2d44af | 46 | #include "x25519.h" |
643eb1bb | 47 | #include "x448.h" |
5c3f75ec | 48 | |
49 | #include "rmd160.h" | |
50 | #include "blowfish-cbc.h" | |
d9d419b0 MW |
51 | #include "poly1305.h" |
52 | #include "salsa20.h" | |
53 | #include "chacha.h" | |
5c3f75ec | 54 | |
55 | #include "cc.h" | |
56 | ||
66ff643c MW |
57 | /*----- Bulk crypto -------------------------------------------------------*/ |
58 | ||
d9d419b0 MW |
59 | /* --- NaCl `secretbox' --- */ |
60 | ||
61 | typedef struct naclbox_encctx { | |
62 | bulk b; | |
63 | const gccipher *cc; | |
64 | gcipher *c; | |
65 | } naclbox_encctx; | |
66 | ||
67 | static bulk *naclbox_init(key *k, const char *calg, const char *halg) | |
68 | { | |
69 | naclbox_encctx *ctx = CREATE(naclbox_encctx); | |
70 | dstr t = DSTR_INIT; | |
71 | const char *q; | |
72 | ||
73 | key_fulltag(k, &t); | |
74 | ||
75 | if ((q = key_getattr(0, k, "cipher")) != 0) calg = q; | |
76 | if (!calg || strcmp(calg, "salsa20") == 0) ctx->cc = &salsa20; | |
77 | else if (strcmp(calg, "salsa20/12") == 0) ctx->cc = &salsa2012; | |
78 | else if (strcmp(calg, "salsa20/8") == 0) ctx->cc = &salsa208; | |
79 | else if (strcmp(calg, "chacha20") == 0) ctx->cc = &chacha20; | |
80 | else if (strcmp(calg, "chacha12") == 0) ctx->cc = &chacha12; | |
81 | else if (strcmp(calg, "chacha8") == 0) ctx->cc = &chacha8; | |
82 | else { | |
83 | die(EXIT_FAILURE, | |
84 | "unknown or inappropriate encryption scheme `%s' in key `%s'", | |
85 | calg, t.buf); | |
86 | } | |
87 | ||
88 | dstr_destroy(&t); | |
89 | return (&ctx->b); | |
90 | } | |
91 | ||
92 | static int naclbox_setup(bulk *b, gcipher *cx) | |
93 | { | |
94 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
95 | octet k[SALSA20_KEYSZ]; | |
96 | ||
97 | GC_ENCRYPT(cx, 0, k, sizeof(k)); | |
98 | ctx->c = GC_INIT(ctx->cc, k, sizeof(k)); | |
99 | return (0); | |
100 | } | |
101 | ||
102 | static size_t naclbox_overhead(bulk *b) { return (POLY1305_TAGSZ); } | |
103 | ||
104 | static void naclbox_destroy(bulk *b) | |
105 | { | |
106 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
107 | ||
108 | GC_DESTROY(ctx->c); | |
109 | DESTROY(ctx); | |
110 | } | |
111 | ||
112 | static const char *naclbox_encdoit(bulk *b, uint32 seq, buf *bb, | |
113 | const void *p, size_t sz) | |
114 | { | |
115 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
116 | octet t[32]; | |
117 | poly1305_key ak; | |
118 | poly1305_ctx a; | |
119 | octet *tag, *ct; | |
120 | ||
121 | STORE32(t, seq); STORE32(t + 4, 0); GC_SETIV(ctx->c, t); | |
122 | GC_ENCRYPT(ctx->c, 0, t, POLY1305_KEYSZ + POLY1305_MASKSZ); | |
123 | poly1305_keyinit(&ak, t, POLY1305_KEYSZ); | |
124 | poly1305_macinit(&a, &ak, t + POLY1305_KEYSZ); | |
125 | ||
126 | tag = buf_get(bb, POLY1305_TAGSZ); assert(tag); | |
127 | ct = buf_get(bb, sz); assert(ct); | |
128 | GC_ENCRYPT(ctx->c, p, ct, sz); | |
129 | poly1305_hash(&a, ct, sz); | |
130 | poly1305_done(&a, tag); | |
131 | return (0); | |
132 | } | |
133 | ||
134 | static const char *naclbox_decdoit(bulk *b, uint32 seq, buf *bb, | |
135 | const void *p, size_t sz) | |
136 | { | |
137 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
138 | buf bin; | |
139 | octet t[32]; | |
140 | poly1305_key ak; | |
141 | poly1305_ctx a; | |
142 | octet *tag, *ct, *pt; | |
143 | ||
144 | STORE32(t, seq); STORE32(t + 4, 0); GC_SETIV(ctx->c, t); | |
145 | GC_ENCRYPT(ctx->c, 0, t, POLY1305_KEYSZ + POLY1305_MASKSZ); | |
146 | poly1305_keyinit(&ak, t, POLY1305_KEYSZ); | |
147 | poly1305_macinit(&a, &ak, t + POLY1305_KEYSZ); | |
148 | ||
149 | buf_init(&bin, (/*unconst*/ void *)p, sz); | |
150 | if ((tag = buf_get(&bin, POLY1305_TAGSZ)) == 0) return ("no tag"); | |
151 | ct = BCUR(&bin); sz = BLEFT(&bin); | |
152 | poly1305_hash(&a, ct, sz); | |
153 | poly1305_done(&a, t); | |
154 | if (!ct_memeq(t, tag, POLY1305_TAGSZ)) return ("authentication failure"); | |
155 | pt = buf_get(bb, sz); assert(pt); | |
156 | GC_DECRYPT(ctx->c, ct, pt, sz); | |
157 | return (0); | |
158 | } | |
159 | ||
160 | static const bulkops naclbox_encops = { | |
161 | naclbox_init, naclbox_setup, naclbox_overhead, | |
162 | naclbox_encdoit, naclbox_destroy | |
163 | }, naclbox_decops = { | |
164 | naclbox_init, naclbox_setup, naclbox_overhead, | |
165 | naclbox_decdoit, naclbox_destroy | |
166 | }; | |
167 | ||
66ff643c MW |
168 | /* --- Generic composition --- */ |
169 | ||
170 | typedef struct gencomp_encctx { | |
171 | bulk b; | |
172 | const gccipher *cc; | |
173 | const gcmac *mc; | |
174 | gcipher *c, *cx; | |
175 | gmac *m; | |
176 | octet *t; size_t tsz; | |
177 | } gencomp_encctx; | |
178 | ||
179 | static bulk *gencomp_init(key *k, const char *calg, const char *halg) | |
180 | { | |
181 | gencomp_encctx *ctx = CREATE(gencomp_encctx); | |
182 | const char *q; | |
183 | dstr d = DSTR_INIT, t = DSTR_INIT; | |
184 | ||
185 | key_fulltag(k, &t); | |
186 | ||
187 | if ((q = key_getattr(0, k, "cipher")) != 0) calg = q; | |
188 | if (!calg) ctx->cc = &blowfish_cbc; | |
189 | else if ((ctx->cc = gcipher_byname(calg)) == 0) { | |
190 | die(EXIT_FAILURE, "encryption scheme `%s' not found in key `%s'", | |
191 | calg, t.buf); | |
192 | } | |
193 | ||
194 | dstr_reset(&d); | |
195 | if ((q = key_getattr(0, k, "mac")) == 0) { | |
196 | dstr_putf(&d, "%s-hmac", halg); | |
197 | q = d.buf; | |
198 | } | |
199 | if ((ctx->mc = gmac_byname(q)) == 0) { | |
200 | die(EXIT_FAILURE, | |
201 | "message authentication code `%s' not found in key `%s'", | |
202 | q, t.buf); | |
203 | } | |
204 | ||
205 | return (&ctx->b); | |
206 | } | |
207 | ||
208 | static int gencomp_setup(bulk *b, gcipher *cx) | |
209 | { | |
210 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
211 | size_t cn, mn, n; | |
212 | octet *kd; | |
213 | ||
214 | ctx->cx = cx; | |
215 | n = ctx->cc->blksz; | |
216 | cn = keysz(0, ctx->cc->keysz); if (cn > n) n = cn; | |
217 | mn = keysz(0, ctx->mc->keysz); if (mn > n) n = mn; | |
218 | ctx->t = kd = xmalloc(n); ctx->tsz = n; | |
219 | GC_ENCRYPT(cx, 0, kd, cn); | |
220 | ctx->c = GC_INIT(ctx->cc, kd, cn); | |
221 | GC_ENCRYPT(cx, 0, kd, mn); | |
222 | ctx->m = GM_KEY(ctx->mc, kd, mn); | |
223 | return (0); | |
224 | } | |
225 | ||
226 | static size_t gencomp_overhead(bulk *b) | |
227 | { | |
228 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
229 | return (ctx->cc->blksz + ctx->mc->hashsz); } | |
230 | ||
231 | static void gencomp_destroy(bulk *b) | |
232 | { | |
233 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
234 | ||
235 | GC_DESTROY(ctx->c); | |
236 | GC_DESTROY(ctx->m); | |
237 | xfree(ctx->t); | |
238 | DESTROY(ctx); | |
239 | } | |
240 | ||
241 | static const char *gencomp_encdoit(bulk *b, uint32 seq, buf *bb, | |
242 | const void *p, size_t sz) | |
243 | { | |
244 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
245 | octet *tag, *ct; | |
246 | ghash *h = GM_INIT(ctx->m); | |
247 | ||
248 | GH_HASHU32(h, seq); | |
249 | if (ctx->cc->blksz) { | |
250 | GC_ENCRYPT(ctx->cx, 0, ctx->t, ctx->cc->blksz); | |
251 | GC_SETIV(ctx->c, ctx->t); | |
252 | } | |
253 | tag = buf_get(bb, ctx->mc->hashsz); assert(tag); | |
254 | ct = buf_get(bb, sz); assert(ct); | |
255 | GC_ENCRYPT(ctx->c, p, ct, sz); | |
256 | GH_HASH(h, ct, sz); | |
257 | GH_DONE(h, tag); | |
258 | GH_DESTROY(h); | |
259 | return (0); | |
260 | } | |
261 | ||
262 | static const char *gencomp_decdoit(bulk *b, uint32 seq, buf *bb, | |
263 | const void *p, size_t sz) | |
264 | { | |
265 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
266 | buf bin; | |
267 | const octet *tag, *ct; | |
268 | octet *pt; | |
269 | ghash *h; | |
270 | int ok; | |
271 | ||
272 | buf_init(&bin, (/*unconst*/ void *)p, sz); | |
273 | if ((tag = buf_get(&bin, ctx->mc->hashsz)) == 0) return ("no tag"); | |
274 | ct = BCUR(&bin); sz = BLEFT(&bin); | |
275 | pt = buf_get(bb, sz); assert(pt); | |
276 | ||
277 | h = GM_INIT(ctx->m); | |
278 | GH_HASHU32(h, seq); | |
279 | GH_HASH(h, ct, sz); | |
280 | ok = ct_memeq(tag, GH_DONE(h, 0), ctx->mc->hashsz); | |
281 | GH_DESTROY(h); | |
282 | if (!ok) return ("authentication failure"); | |
283 | ||
284 | if (ctx->cc->blksz) { | |
285 | GC_ENCRYPT(ctx->cx, 0, ctx->t, ctx->cc->blksz); | |
286 | GC_SETIV(ctx->c, ctx->t); | |
287 | } | |
288 | GC_DECRYPT(ctx->c, ct, pt, sz); | |
289 | return (0); | |
290 | } | |
291 | ||
292 | static const bulkops gencomp_encops = { | |
293 | gencomp_init, gencomp_setup, gencomp_overhead, | |
294 | gencomp_encdoit, gencomp_destroy | |
295 | }, gencomp_decops = { | |
296 | gencomp_init, gencomp_setup, gencomp_overhead, | |
297 | gencomp_decdoit, gencomp_destroy | |
298 | }; | |
299 | ||
300 | const struct bulktab bulktab[] = { | |
301 | { "gencomp", &gencomp_encops, &gencomp_decops }, | |
d9d419b0 | 302 | { "naclbox", &naclbox_encops, &naclbox_decops }, |
66ff643c MW |
303 | { 0, 0, 0 } |
304 | }; | |
305 | ||
5c3f75ec | 306 | /*----- Key encapsulation -------------------------------------------------*/ |
307 | ||
308 | /* --- RSA --- */ | |
309 | ||
310 | typedef struct rsa_encctx { | |
311 | kem k; | |
312 | rsa_pubctx rp; | |
313 | } rsa_encctx; | |
314 | ||
315 | static kem *rsa_encinit(key *k, void *kd) | |
316 | { | |
317 | rsa_encctx *re = CREATE(rsa_encctx); | |
318 | rsa_pubcreate(&re->rp, kd); | |
319 | return (&re->k); | |
320 | } | |
321 | ||
322 | static int rsa_encdoit(kem *k, dstr *d, ghash *h) | |
323 | { | |
324 | rsa_encctx *re = (rsa_encctx *)k; | |
325 | mp *x = mprand_range(MP_NEW, re->rp.rp->n, &rand_global, 0); | |
326 | mp *y = rsa_pubop(&re->rp, MP_NEW, x); | |
327 | size_t n = mp_octets(re->rp.rp->n); | |
328 | dstr_ensure(d, n); | |
329 | mp_storeb(x, d->buf, n); | |
330 | GH_HASH(h, d->buf, n); | |
331 | mp_storeb(y, d->buf, n); | |
332 | d->len += n; | |
333 | mp_drop(x); | |
334 | mp_drop(y); | |
335 | return (0); | |
336 | } | |
337 | ||
338 | static const char *rsa_lengthcheck(mp *n) | |
339 | { | |
340 | if (mp_bits(n) < 1020) return ("key too short"); | |
341 | return (0); | |
342 | } | |
343 | ||
344 | static const char *rsa_enccheck(kem *k) | |
345 | { | |
346 | rsa_encctx *re = (rsa_encctx *)k; | |
347 | const char *e; | |
348 | if ((e = rsa_lengthcheck(re->rp.rp->n)) != 0) return (e); | |
349 | return (0); | |
350 | } | |
351 | ||
352 | static void rsa_encdestroy(kem *k) | |
353 | { | |
354 | rsa_encctx *re = (rsa_encctx *)k; | |
355 | rsa_pubdestroy(&re->rp); | |
356 | DESTROY(re); | |
357 | } | |
358 | ||
359 | static const kemops rsa_encops = { | |
360 | rsa_pubfetch, sizeof(rsa_pub), | |
361 | rsa_encinit, rsa_encdoit, rsa_enccheck, rsa_encdestroy | |
362 | }; | |
363 | ||
364 | typedef struct rsa_decctx { | |
365 | kem k; | |
366 | rsa_privctx rp; | |
367 | } rsa_decctx; | |
368 | ||
369 | static kem *rsa_decinit(key *k, void *kd) | |
370 | { | |
371 | rsa_decctx *rd = CREATE(rsa_decctx); | |
372 | rsa_privcreate(&rd->rp, kd, &rand_global); | |
373 | return (&rd->k); | |
374 | } | |
375 | ||
376 | static int rsa_decdoit(kem *k, dstr *d, ghash *h) | |
377 | { | |
378 | rsa_decctx *rd = (rsa_decctx *)k; | |
379 | mp *x = mp_loadb(MP_NEW, d->buf, d->len); | |
380 | size_t n; | |
381 | char *p; | |
382 | ||
383 | if (MP_CMP(x, >=, rd->rp.rp->n)) { | |
384 | mp_drop(x); | |
385 | return (-1); | |
386 | } | |
387 | n = mp_octets(rd->rp.rp->n); | |
388 | p = xmalloc(n); | |
389 | x = rsa_privop(&rd->rp, x, x); | |
390 | mp_storeb(x, p, n); | |
391 | GH_HASH(h, p, n); | |
392 | mp_drop(x); | |
393 | xfree(p); | |
394 | return (0); | |
395 | } | |
396 | ||
397 | static const char *rsa_deccheck(kem *k) | |
398 | { | |
399 | rsa_decctx *rd = (rsa_decctx *)k; | |
400 | const char *e; | |
401 | if ((e = rsa_lengthcheck(rd->rp.rp->n)) != 0) return (e); | |
402 | return (0); | |
403 | } | |
404 | ||
405 | static void rsa_decdestroy(kem *k) | |
406 | { | |
407 | rsa_decctx *rd = (rsa_decctx *)k; | |
408 | rsa_privdestroy(&rd->rp); | |
409 | DESTROY(rd); | |
410 | } | |
411 | ||
412 | static const kemops rsa_decops = { | |
413 | rsa_privfetch, sizeof(rsa_priv), | |
414 | rsa_decinit, rsa_decdoit, rsa_deccheck, rsa_decdestroy | |
415 | }; | |
416 | ||
417 | /* --- DH and EC --- */ | |
418 | ||
419 | typedef struct dh_encctx { | |
420 | kem k; | |
421 | group *g; | |
422 | mp *x; | |
423 | ge *y; | |
424 | } dh_encctx; | |
425 | ||
45c0fd36 | 426 | static dh_encctx *dh_doinit(key *k, const gprime_param *gp, mp *y, |
3688eb75 | 427 | group *(*makegroup)(const gprime_param *), |
428 | const char *what) | |
5c3f75ec | 429 | { |
430 | dh_encctx *de = CREATE(dh_encctx); | |
431 | dstr t = DSTR_INIT; | |
432 | ||
433 | key_fulltag(k, &t); | |
3688eb75 | 434 | if ((de->g = makegroup(gp)) == 0) |
435 | die(EXIT_FAILURE, "bad %s group in key `%s'", what, t.buf); | |
5c3f75ec | 436 | de->x = MP_NEW; |
437 | de->y = G_CREATE(de->g); | |
438 | if (G_FROMINT(de->g, de->y, y)) | |
439 | die(EXIT_FAILURE, "bad public key `%s'", t.buf); | |
440 | dstr_destroy(&t); | |
441 | return (de); | |
442 | } | |
443 | ||
444 | static dh_encctx *ec_doinit(key *k, const char *cstr, const ec *y) | |
445 | { | |
446 | dh_encctx *de = CREATE(dh_encctx); | |
447 | ec_info ei; | |
448 | const char *e; | |
449 | dstr t = DSTR_INIT; | |
450 | ||
451 | key_fulltag(k, &t); | |
452 | if ((e = ec_getinfo(&ei, cstr)) != 0 || | |
453 | (de->g = group_ec(&ei)) == 0) | |
454 | die(EXIT_FAILURE, "bad elliptic curve spec in key `%s': %s", t.buf, e); | |
455 | de->x = MP_NEW; | |
456 | de->y = G_CREATE(de->g); | |
457 | if (G_FROMEC(de->g, de->y, y)) | |
458 | die(EXIT_FAILURE, "bad public curve point `%s'", t.buf); | |
459 | dstr_destroy(&t); | |
460 | return (de); | |
461 | } | |
462 | ||
463 | static kem *dh_encinit(key *k, void *kd) | |
464 | { | |
465 | dh_pub *dp = kd; | |
3688eb75 | 466 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_prime, "prime"); |
467 | return (&de->k); | |
468 | } | |
469 | ||
470 | static kem *bindh_encinit(key *k, void *kd) | |
471 | { | |
472 | dh_pub *dp = kd; | |
473 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_binary, "binary"); | |
5c3f75ec | 474 | return (&de->k); |
475 | } | |
476 | ||
477 | static kem *ec_encinit(key *k, void *kd) | |
478 | { | |
479 | ec_pub *ep = kd; | |
480 | dh_encctx *de = ec_doinit(k, ep->cstr, &ep->p); | |
481 | return (&de->k); | |
482 | } | |
483 | ||
484 | static int dh_encdoit(kem *k, dstr *d, ghash *h) | |
485 | { | |
486 | dh_encctx *de = (dh_encctx *)k; | |
487 | mp *r = mprand_range(MP_NEW, de->g->r, &rand_global, 0); | |
488 | ge *x = G_CREATE(de->g); | |
489 | ge *y = G_CREATE(de->g); | |
490 | size_t n = de->g->noctets; | |
491 | buf b; | |
45c0fd36 | 492 | |
5c3f75ec | 493 | G_EXP(de->g, x, de->g->g, r); |
494 | G_EXP(de->g, y, de->y, r); | |
495 | dstr_ensure(d, n); | |
496 | buf_init(&b, d->buf, n); | |
497 | G_TORAW(de->g, &b, y); | |
498 | GH_HASH(h, BBASE(&b), BLEN(&b)); | |
499 | buf_init(&b, d->buf, n); | |
500 | G_TORAW(de->g, &b, x); | |
501 | GH_HASH(h, BBASE(&b), BLEN(&b)); | |
502 | d->len += BLEN(&b); | |
503 | mp_drop(r); | |
504 | G_DESTROY(de->g, x); | |
505 | G_DESTROY(de->g, y); | |
506 | return (0); | |
507 | } | |
508 | ||
509 | static const char *dh_enccheck(kem *k) | |
510 | { | |
511 | dh_encctx *de = (dh_encctx *)k; | |
512 | const char *e; | |
513 | if ((e = G_CHECK(de->g, &rand_global)) != 0) | |
514 | return (0); | |
515 | if (group_check(de->g, de->y)) | |
516 | return ("public key not in subgroup"); | |
517 | return (0); | |
518 | } | |
519 | ||
520 | static void dh_encdestroy(kem *k) | |
521 | { | |
522 | dh_encctx *de = (dh_encctx *)k; | |
523 | G_DESTROY(de->g, de->y); | |
524 | mp_drop(de->x); | |
525 | G_DESTROYGROUP(de->g); | |
6f313264 | 526 | DESTROY(de); |
5c3f75ec | 527 | } |
528 | ||
529 | static const kemops dh_encops = { | |
530 | dh_pubfetch, sizeof(dh_pub), | |
531 | dh_encinit, dh_encdoit, dh_enccheck, dh_encdestroy | |
532 | }; | |
533 | ||
3688eb75 | 534 | static const kemops bindh_encops = { |
535 | dh_pubfetch, sizeof(dh_pub), | |
536 | bindh_encinit, dh_encdoit, dh_enccheck, dh_encdestroy | |
537 | }; | |
538 | ||
5c3f75ec | 539 | static const kemops ec_encops = { |
540 | ec_pubfetch, sizeof(ec_pub), | |
541 | ec_encinit, dh_encdoit, dh_enccheck, dh_encdestroy | |
542 | }; | |
543 | ||
544 | static kem *dh_decinit(key *k, void *kd) | |
545 | { | |
546 | dh_priv *dp = kd; | |
3688eb75 | 547 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_prime, "prime"); |
548 | de->x = MP_COPY(dp->x); | |
549 | return (&de->k); | |
550 | } | |
551 | ||
552 | static kem *bindh_decinit(key *k, void *kd) | |
553 | { | |
554 | dh_priv *dp = kd; | |
555 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_binary, "binary"); | |
5c3f75ec | 556 | de->x = MP_COPY(dp->x); |
557 | return (&de->k); | |
558 | } | |
559 | ||
560 | static kem *ec_decinit(key *k, void *kd) | |
561 | { | |
562 | ec_priv *ep = kd; | |
563 | dh_encctx *de = ec_doinit(k, ep->cstr, &ep->p); | |
564 | de->x = MP_COPY(ep->x); | |
565 | return (&de->k); | |
566 | } | |
567 | ||
568 | static int dh_decdoit(kem *k, dstr *d, ghash *h) | |
569 | { | |
570 | dh_encctx *de = (dh_encctx *)k; | |
571 | ge *x = G_CREATE(de->g); | |
572 | size_t n = de->g->noctets; | |
573 | void *p = xmalloc(n); | |
574 | buf b; | |
575 | int rc = -1; | |
576 | ||
577 | buf_init(&b, d->buf, d->len); | |
578 | if (G_FROMRAW(de->g, &b, x) || group_check(de->g, x)) | |
579 | goto done; | |
580 | G_EXP(de->g, x, x, de->x); | |
581 | buf_init(&b, p, n); | |
582 | G_TORAW(de->g, &b, x); | |
583 | GH_HASH(h, BBASE(&b), BLEN(&b)); | |
584 | GH_HASH(h, d->buf, d->len); | |
585 | rc = 0; | |
586 | done: | |
587 | G_DESTROY(de->g, x); | |
588 | xfree(p); | |
589 | return (rc); | |
590 | } | |
591 | ||
592 | static const kemops dh_decops = { | |
593 | dh_privfetch, sizeof(dh_priv), | |
594 | dh_decinit, dh_decdoit, dh_enccheck, dh_encdestroy | |
595 | }; | |
596 | ||
3688eb75 | 597 | static const kemops bindh_decops = { |
598 | dh_privfetch, sizeof(dh_priv), | |
599 | bindh_decinit, dh_decdoit, dh_enccheck, dh_encdestroy | |
600 | }; | |
601 | ||
5c3f75ec | 602 | static const kemops ec_decops = { |
603 | ec_privfetch, sizeof(ec_priv), | |
604 | ec_decinit, dh_decdoit, dh_enccheck, dh_encdestroy | |
605 | }; | |
606 | ||
593f7bd3 MW |
607 | /* --- X25519 and similar schemes --- */ |
608 | ||
609 | #define XDHS(_) \ | |
610 | _(x25519, X25519) \ | |
611 | _(x448, X448) | |
612 | ||
613 | #define XDHDEF(xdh, XDH) \ | |
614 | \ | |
615 | static kem *xdh##_encinit(key *k, void *kd) { return (CREATE(kem)); } \ | |
616 | static void xdh##_encdestroy(kem *k) { DESTROY(k); } \ | |
617 | \ | |
618 | static const char *xdh##_enccheck(kem *k) \ | |
619 | { \ | |
620 | xdh##_pub *kd = k->kd; \ | |
621 | \ | |
622 | if (kd->pub.sz != XDH##_PUBSZ) \ | |
623 | return ("incorrect " #XDH "public key length"); \ | |
624 | return (0); \ | |
625 | } \ | |
626 | \ | |
627 | static int xdh##_encdoit(kem *k, dstr *d, ghash *h) \ | |
628 | { \ | |
629 | octet t[XDH##_KEYSZ], z[XDH##_OUTSZ]; \ | |
630 | xdh##_pub *kd = k->kd; \ | |
631 | \ | |
632 | rand_get(RAND_GLOBAL, t, sizeof(t)); \ | |
633 | dstr_ensure(d, XDH##_PUBSZ); \ | |
634 | xdh((octet *)d->buf, t, xdh##_base); \ | |
635 | xdh(z, t, kd->pub.k); \ | |
636 | d->len += XDH##_PUBSZ; \ | |
637 | GH_HASH(h, d->buf, XDH##_PUBSZ); \ | |
638 | GH_HASH(h, z, XDH##_OUTSZ); \ | |
639 | return (0); \ | |
640 | } \ | |
641 | \ | |
642 | static const char *xdh##_deccheck(kem *k) \ | |
643 | { \ | |
644 | xdh##_priv *kd = k->kd; \ | |
645 | \ | |
646 | if (kd->priv.sz != XDH##_KEYSZ) \ | |
647 | return ("incorrect " #XDH " private key length"); \ | |
648 | if (kd->pub.sz != XDH##_PUBSZ) \ | |
649 | return ("incorrect " #XDH " public key length"); \ | |
650 | return (0); \ | |
651 | } \ | |
652 | \ | |
653 | static int xdh##_decdoit(kem *k, dstr *d, ghash *h) \ | |
654 | { \ | |
655 | octet z[XDH##_OUTSZ]; \ | |
656 | xdh##_priv *kd = k->kd; \ | |
657 | int rc = -1; \ | |
658 | \ | |
659 | if (d->len != XDH##_PUBSZ) goto done; \ | |
660 | xdh(z, kd->priv.k, (const octet *)d->buf); \ | |
661 | GH_HASH(h, d->buf, XDH##_PUBSZ); \ | |
662 | GH_HASH(h, z, XDH##_OUTSZ); \ | |
663 | rc = 0; \ | |
664 | done: \ | |
665 | return (rc); \ | |
666 | } \ | |
667 | \ | |
668 | static const kemops xdh##_encops = { \ | |
669 | xdh##_pubfetch, sizeof(xdh##_pub), \ | |
670 | xdh##_encinit, xdh##_encdoit, xdh##_enccheck, xdh##_encdestroy \ | |
671 | }; \ | |
672 | \ | |
673 | static const kemops xdh##_decops = { \ | |
674 | xdh##_privfetch, sizeof(xdh##_priv), \ | |
675 | xdh##_encinit, xdh##_decdoit, xdh##_deccheck, xdh##_encdestroy \ | |
676 | }; | |
677 | ||
678 | XDHS(XDHDEF) | |
679 | #undef XDHDEF | |
643eb1bb | 680 | |
02dfbd5b MW |
681 | /* --- Symmetric --- */ |
682 | ||
683 | typedef struct symm_ctx { | |
684 | kem k; | |
685 | key_packdef kp; | |
686 | key_bin kb; | |
687 | } symm_ctx; | |
688 | ||
689 | static kem *symm_init(key *k, void *kd) | |
690 | { | |
691 | symm_ctx *s; | |
692 | dstr d = DSTR_INIT; | |
693 | int err; | |
694 | ||
695 | s = CREATE(symm_ctx); | |
696 | ||
697 | key_fulltag(k, &d); | |
698 | s->kp.e = KENC_BINARY; | |
699 | s->kp.p = &s->kb; | |
700 | s->kp.kd = 0; | |
701 | ||
702 | if ((err = key_unpack(&s->kp, kd, &d)) != 0) { | |
703 | die(EXIT_FAILURE, "failed to unpack symmetric key `%s': %s", | |
704 | d.buf, key_strerror(err)); | |
705 | } | |
706 | dstr_destroy(&d); | |
707 | return (&s->k); | |
708 | } | |
709 | ||
710 | static int symm_decdoit(kem *k, dstr *d, ghash *h) | |
711 | { | |
712 | symm_ctx *s = (symm_ctx *)k; | |
713 | ||
714 | GH_HASH(h, s->kb.k, s->kb.sz); | |
715 | GH_HASH(h, d->buf, d->len); | |
716 | return (0); | |
717 | } | |
718 | ||
719 | static int symm_encdoit(kem *k, dstr *d, ghash *h) | |
720 | { | |
721 | dstr_ensure(d, h->ops->c->hashsz); | |
722 | d->len += h->ops->c->hashsz; | |
723 | rand_get(RAND_GLOBAL, d->buf, d->len); | |
724 | return (symm_decdoit(k, d, h)); | |
725 | } | |
726 | ||
727 | static const char *symm_check(kem *k) { return (0); } | |
728 | ||
729 | static void symm_destroy(kem *k) | |
730 | { symm_ctx *s = (symm_ctx *)k; key_unpackdone(&s->kp); } | |
731 | ||
732 | static const kemops symm_encops = { | |
733 | 0, 0, | |
734 | symm_init, symm_encdoit, symm_check, symm_destroy | |
735 | }; | |
736 | ||
737 | static const kemops symm_decops = { | |
738 | 0, 0, | |
739 | symm_init, symm_decdoit, symm_check, symm_destroy | |
740 | }; | |
741 | ||
5c3f75ec | 742 | /* --- The switch table --- */ |
743 | ||
c65df279 | 744 | const struct kemtab kemtab[] = { |
5c3f75ec | 745 | { "rsa", &rsa_encops, &rsa_decops }, |
746 | { "dh", &dh_encops, &dh_decops }, | |
3688eb75 | 747 | { "bindh", &bindh_encops, &bindh_decops }, |
5c3f75ec | 748 | { "ec", &ec_encops, &ec_decops }, |
593f7bd3 MW |
749 | #define XDHTAB(xdh, XDH) \ |
750 | { #xdh, &xdh##_encops, &xdh##_decops }, | |
751 | XDHS(XDHTAB) | |
752 | #undef XDHTAB | |
02dfbd5b | 753 | { "symm", &symm_encops, &symm_decops }, |
5c3f75ec | 754 | { 0, 0, 0 } |
755 | }; | |
756 | ||
757 | /* --- @getkem@ --- * | |
758 | * | |
759 | * Arguments: @key *k@ = the key to load | |
760 | * @const char *app@ = application name | |
761 | * @int wantpriv@ = nonzero if we want to decrypt | |
66ff643c | 762 | * @bulk **bc@ = bulk crypto context to set up |
5c3f75ec | 763 | * |
764 | * Returns: A key-encapsulating thing. | |
765 | * | |
766 | * Use: Loads a key. | |
767 | */ | |
768 | ||
66ff643c | 769 | kem *getkem(key *k, const char *app, int wantpriv, bulk **bc) |
5c3f75ec | 770 | { |
66ff643c | 771 | const char *kalg, *halg = 0, *balg = 0; |
5c3f75ec | 772 | dstr d = DSTR_INIT; |
773 | dstr t = DSTR_INIT; | |
774 | size_t n; | |
775 | char *p = 0; | |
776 | const char *q; | |
777 | kem *kk; | |
778 | const struct kemtab *kt; | |
779 | const kemops *ko; | |
66ff643c MW |
780 | const struct bulktab *bt; |
781 | const bulkops *bo; | |
5c3f75ec | 782 | void *kd; |
783 | int e; | |
784 | key_packdef *kp; | |
785 | ||
786 | /* --- Setup stuff --- */ | |
787 | ||
788 | key_fulltag(k, &t); | |
789 | ||
790 | /* --- Get the KEM name --- * | |
791 | * | |
792 | * Take the attribute if it's there; otherwise use the key type. | |
793 | */ | |
794 | ||
795 | n = strlen(app); | |
796 | if ((q = key_getattr(0, k, "kem")) != 0) { | |
797 | dstr_puts(&d, q); | |
798 | p = d.buf; | |
799 | } else if (strncmp(k->type, app, n) == 0 && k->type[n] == '-') { | |
800 | dstr_puts(&d, k->type); | |
801 | p = d.buf + n + 1; | |
802 | } else | |
803 | die(EXIT_FAILURE, "no KEM for key `%s'", t.buf); | |
804 | kalg = p; | |
805 | ||
66ff643c | 806 | /* --- Grab the bulk encryption scheme --- * |
5c3f75ec | 807 | * |
808 | * Grab it from the KEM if it's there, but override it from the attribute. | |
809 | */ | |
810 | ||
811 | if (p && (p = strchr(p, '/')) != 0) { | |
812 | *p++ = 0; | |
66ff643c | 813 | balg = p; |
5c3f75ec | 814 | } |
66ff643c MW |
815 | if ((q = key_getattr(0, k, "bulk")) != 0) |
816 | balg = q; | |
5c3f75ec | 817 | |
818 | /* --- Grab the hash function --- */ | |
819 | ||
820 | if (p && (p = strchr(p, '/')) != 0) { | |
821 | *p++ = 0; | |
822 | halg = p; | |
823 | } | |
824 | if ((q = key_getattr(0, k, "hash")) != 0) | |
825 | halg = q; | |
826 | ||
827 | /* --- Instantiate the KEM --- */ | |
828 | ||
829 | for (kt = kemtab; kt->name; kt++) { | |
830 | if (strcmp(kt->name, kalg) == 0) | |
831 | goto k_found; | |
832 | } | |
833 | die(EXIT_FAILURE, "key encapsulation mechanism `%s' not found in key `%s'", | |
834 | kalg, t.buf); | |
835 | k_found:; | |
836 | ko = wantpriv ? kt->decops : kt->encops; | |
02dfbd5b MW |
837 | if (!ko->kf) { |
838 | kd = k->k; | |
839 | key_incref(kd); | |
78ec50fa | 840 | kp = 0; |
02dfbd5b MW |
841 | } else { |
842 | kd = xmalloc(ko->kdsz); | |
843 | kp = key_fetchinit(ko->kf, 0, kd); | |
844 | if ((e = key_fetch(kp, k)) != 0) { | |
845 | die(EXIT_FAILURE, "error fetching key `%s': %s", | |
846 | t.buf, key_strerror(e)); | |
847 | } | |
848 | } | |
5c3f75ec | 849 | kk = ko->init(k, kd); |
850 | kk->kp = kp; | |
851 | kk->ops = ko; | |
852 | kk->kd = kd; | |
853 | ||
66ff643c | 854 | /* --- Set up the bulk crypto --- */ |
5c3f75ec | 855 | |
856 | if (!halg) | |
66ff643c MW |
857 | kk->hc = &rmd160; |
858 | else if ((kk->hc = ghash_byname(halg)) == 0) { | |
5c3f75ec | 859 | die(EXIT_FAILURE, "hash algorithm `%s' not found in key `%s'", |
860 | halg, t.buf); | |
861 | } | |
862 | ||
5c3f75ec | 863 | dstr_reset(&d); |
864 | if ((q = key_getattr(0, k, "kdf")) == 0) { | |
66ff643c | 865 | dstr_putf(&d, "%s-mgf", kk->hc->name); |
5c3f75ec | 866 | q = d.buf; |
867 | } | |
66ff643c | 868 | if ((kk->cxc = gcipher_byname(q)) == 0) { |
5c3f75ec | 869 | die(EXIT_FAILURE, "encryption scheme (KDF) `%s' not found in key `%s'", |
870 | q, t.buf); | |
871 | } | |
45c0fd36 | 872 | |
66ff643c MW |
873 | if (!balg) |
874 | bt = bulktab; | |
875 | else { | |
876 | for (bt = bulktab, bo = 0; bt->name; bt++) { | |
877 | if (strcmp(balg, bt->name) == 0) | |
878 | { balg = 0; goto b_found; } | |
879 | n = strlen(bt->name); | |
880 | if (strncmp(balg, bt->name, n) == 0 && balg[n] == '-') | |
881 | { balg += n + 1; goto b_found; } | |
882 | } | |
883 | bt = bulktab; | |
884 | b_found:; | |
5c3f75ec | 885 | } |
66ff643c MW |
886 | bo = wantpriv ? bt->decops : bt->encops; |
887 | *bc = bo->init(k, balg, kk->hc->name); | |
888 | (*bc)->ops = bo; | |
5c3f75ec | 889 | |
890 | /* --- Tidy up --- */ | |
891 | ||
892 | dstr_destroy(&d); | |
893 | dstr_destroy(&t); | |
894 | return (kk); | |
895 | } | |
896 | ||
897 | /* --- @setupkem@ --- * | |
898 | * | |
899 | * Arguments: @kem *k@ = key-encapsulation thing | |
900 | * @dstr *d@ = key-encapsulation data | |
66ff643c | 901 | * @bulk *bc@ = bulk crypto context to set up |
5c3f75ec | 902 | * |
903 | * Returns: Zero on success, nonzero on failure. | |
904 | * | |
905 | * Use: Initializes all the various symmetric things from a KEM. | |
906 | */ | |
907 | ||
66ff643c | 908 | int setupkem(kem *k, dstr *d, bulk *bc) |
5c3f75ec | 909 | { |
910 | octet *kd; | |
66ff643c | 911 | size_t n; |
5c3f75ec | 912 | ghash *h; |
c65df279 | 913 | int rc = -1; |
5c3f75ec | 914 | |
66ff643c | 915 | h = GH_INIT(k->hc); |
5c3f75ec | 916 | if (k->ops->doit(k, d, h)) |
917 | goto done; | |
66ff643c | 918 | n = keysz(GH_CLASS(h)->hashsz, k->cxc->keysz); |
5c3f75ec | 919 | if (!n) |
920 | goto done; | |
921 | kd = GH_DONE(h, 0); | |
66ff643c MW |
922 | k->cx = GC_INIT(k->cxc, kd, n); |
923 | bc->ops->setup(bc, k->cx); | |
5c3f75ec | 924 | |
925 | rc = 0; | |
926 | done: | |
927 | GH_DESTROY(h); | |
928 | return (rc); | |
929 | } | |
930 | ||
931 | /* --- @freekem@ --- * | |
932 | * | |
933 | * Arguments: @kem *k@ = key-encapsulation thing | |
934 | * | |
935 | * Returns: --- | |
936 | * | |
937 | * Use: Frees up a key-encapsulation thing. | |
938 | */ | |
939 | ||
940 | void freekem(kem *k) | |
941 | { | |
02dfbd5b MW |
942 | if (!k->ops->kf) |
943 | key_drop(k->kd); | |
944 | else { | |
945 | key_fetchdone(k->kp); | |
946 | xfree(k->kd); | |
947 | } | |
66ff643c | 948 | GC_DESTROY(k->cx); |
5c3f75ec | 949 | k->ops->destroy(k); |
950 | } | |
951 | ||
952 | /*----- That's all, folks -------------------------------------------------*/ |