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