Commit | Line | Data |
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5c3f75ec | 1 | /* -*-c-*- |
2 | * | |
5c3f75ec | 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" |
5c3f75ec | 47 | |
48 | #include "rmd160.h" | |
49 | #include "blowfish-cbc.h" | |
d9d419b0 MW |
50 | #include "poly1305.h" |
51 | #include "salsa20.h" | |
52 | #include "chacha.h" | |
5c3f75ec | 53 | |
54 | #include "cc.h" | |
55 | ||
66ff643c MW |
56 | /*----- Bulk crypto -------------------------------------------------------*/ |
57 | ||
d9d419b0 MW |
58 | /* --- NaCl `secretbox' --- */ |
59 | ||
60 | typedef struct naclbox_encctx { | |
61 | bulk b; | |
62 | const gccipher *cc; | |
63 | gcipher *c; | |
64 | } naclbox_encctx; | |
65 | ||
66 | static bulk *naclbox_init(key *k, const char *calg, const char *halg) | |
67 | { | |
68 | naclbox_encctx *ctx = CREATE(naclbox_encctx); | |
69 | dstr t = DSTR_INIT; | |
70 | const char *q; | |
71 | ||
72 | key_fulltag(k, &t); | |
73 | ||
74 | if ((q = key_getattr(0, k, "cipher")) != 0) calg = q; | |
75 | if (!calg || strcmp(calg, "salsa20") == 0) ctx->cc = &salsa20; | |
76 | else if (strcmp(calg, "salsa20/12") == 0) ctx->cc = &salsa2012; | |
77 | else if (strcmp(calg, "salsa20/8") == 0) ctx->cc = &salsa208; | |
78 | else if (strcmp(calg, "chacha20") == 0) ctx->cc = &chacha20; | |
79 | else if (strcmp(calg, "chacha12") == 0) ctx->cc = &chacha12; | |
80 | else if (strcmp(calg, "chacha8") == 0) ctx->cc = &chacha8; | |
81 | else { | |
82 | die(EXIT_FAILURE, | |
83 | "unknown or inappropriate encryption scheme `%s' in key `%s'", | |
84 | calg, t.buf); | |
85 | } | |
86 | ||
87 | dstr_destroy(&t); | |
88 | return (&ctx->b); | |
89 | } | |
90 | ||
91 | static int naclbox_setup(bulk *b, gcipher *cx) | |
92 | { | |
93 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
94 | octet k[SALSA20_KEYSZ]; | |
95 | ||
96 | GC_ENCRYPT(cx, 0, k, sizeof(k)); | |
97 | ctx->c = GC_INIT(ctx->cc, k, sizeof(k)); | |
98 | return (0); | |
99 | } | |
100 | ||
101 | static size_t naclbox_overhead(bulk *b) { return (POLY1305_TAGSZ); } | |
102 | ||
103 | static void naclbox_destroy(bulk *b) | |
104 | { | |
105 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
106 | ||
107 | GC_DESTROY(ctx->c); | |
108 | DESTROY(ctx); | |
109 | } | |
110 | ||
111 | static const char *naclbox_encdoit(bulk *b, uint32 seq, buf *bb, | |
112 | const void *p, size_t sz) | |
113 | { | |
114 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
115 | octet t[32]; | |
116 | poly1305_key ak; | |
117 | poly1305_ctx a; | |
118 | octet *tag, *ct; | |
119 | ||
120 | STORE32(t, seq); STORE32(t + 4, 0); GC_SETIV(ctx->c, t); | |
121 | GC_ENCRYPT(ctx->c, 0, t, POLY1305_KEYSZ + POLY1305_MASKSZ); | |
122 | poly1305_keyinit(&ak, t, POLY1305_KEYSZ); | |
123 | poly1305_macinit(&a, &ak, t + POLY1305_KEYSZ); | |
124 | ||
125 | tag = buf_get(bb, POLY1305_TAGSZ); assert(tag); | |
126 | ct = buf_get(bb, sz); assert(ct); | |
127 | GC_ENCRYPT(ctx->c, p, ct, sz); | |
128 | poly1305_hash(&a, ct, sz); | |
129 | poly1305_done(&a, tag); | |
130 | return (0); | |
131 | } | |
132 | ||
133 | static const char *naclbox_decdoit(bulk *b, uint32 seq, buf *bb, | |
134 | const void *p, size_t sz) | |
135 | { | |
136 | naclbox_encctx *ctx = (naclbox_encctx *)b; | |
137 | buf bin; | |
138 | octet t[32]; | |
139 | poly1305_key ak; | |
140 | poly1305_ctx a; | |
141 | octet *tag, *ct, *pt; | |
142 | ||
143 | STORE32(t, seq); STORE32(t + 4, 0); GC_SETIV(ctx->c, t); | |
144 | GC_ENCRYPT(ctx->c, 0, t, POLY1305_KEYSZ + POLY1305_MASKSZ); | |
145 | poly1305_keyinit(&ak, t, POLY1305_KEYSZ); | |
146 | poly1305_macinit(&a, &ak, t + POLY1305_KEYSZ); | |
147 | ||
148 | buf_init(&bin, (/*unconst*/ void *)p, sz); | |
149 | if ((tag = buf_get(&bin, POLY1305_TAGSZ)) == 0) return ("no tag"); | |
150 | ct = BCUR(&bin); sz = BLEFT(&bin); | |
151 | poly1305_hash(&a, ct, sz); | |
152 | poly1305_done(&a, t); | |
153 | if (!ct_memeq(t, tag, POLY1305_TAGSZ)) return ("authentication failure"); | |
154 | pt = buf_get(bb, sz); assert(pt); | |
155 | GC_DECRYPT(ctx->c, ct, pt, sz); | |
156 | return (0); | |
157 | } | |
158 | ||
159 | static const bulkops naclbox_encops = { | |
160 | naclbox_init, naclbox_setup, naclbox_overhead, | |
161 | naclbox_encdoit, naclbox_destroy | |
162 | }, naclbox_decops = { | |
163 | naclbox_init, naclbox_setup, naclbox_overhead, | |
164 | naclbox_decdoit, naclbox_destroy | |
165 | }; | |
166 | ||
66ff643c MW |
167 | /* --- Generic composition --- */ |
168 | ||
169 | typedef struct gencomp_encctx { | |
170 | bulk b; | |
171 | const gccipher *cc; | |
172 | const gcmac *mc; | |
173 | gcipher *c, *cx; | |
174 | gmac *m; | |
175 | octet *t; size_t tsz; | |
176 | } gencomp_encctx; | |
177 | ||
178 | static bulk *gencomp_init(key *k, const char *calg, const char *halg) | |
179 | { | |
180 | gencomp_encctx *ctx = CREATE(gencomp_encctx); | |
181 | const char *q; | |
182 | dstr d = DSTR_INIT, t = DSTR_INIT; | |
183 | ||
184 | key_fulltag(k, &t); | |
185 | ||
186 | if ((q = key_getattr(0, k, "cipher")) != 0) calg = q; | |
187 | if (!calg) ctx->cc = &blowfish_cbc; | |
188 | else if ((ctx->cc = gcipher_byname(calg)) == 0) { | |
189 | die(EXIT_FAILURE, "encryption scheme `%s' not found in key `%s'", | |
190 | calg, t.buf); | |
191 | } | |
192 | ||
193 | dstr_reset(&d); | |
194 | if ((q = key_getattr(0, k, "mac")) == 0) { | |
195 | dstr_putf(&d, "%s-hmac", halg); | |
196 | q = d.buf; | |
197 | } | |
198 | if ((ctx->mc = gmac_byname(q)) == 0) { | |
199 | die(EXIT_FAILURE, | |
200 | "message authentication code `%s' not found in key `%s'", | |
201 | q, t.buf); | |
202 | } | |
203 | ||
204 | return (&ctx->b); | |
205 | } | |
206 | ||
207 | static int gencomp_setup(bulk *b, gcipher *cx) | |
208 | { | |
209 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
210 | size_t cn, mn, n; | |
211 | octet *kd; | |
212 | ||
213 | ctx->cx = cx; | |
214 | n = ctx->cc->blksz; | |
215 | cn = keysz(0, ctx->cc->keysz); if (cn > n) n = cn; | |
216 | mn = keysz(0, ctx->mc->keysz); if (mn > n) n = mn; | |
217 | ctx->t = kd = xmalloc(n); ctx->tsz = n; | |
218 | GC_ENCRYPT(cx, 0, kd, cn); | |
219 | ctx->c = GC_INIT(ctx->cc, kd, cn); | |
220 | GC_ENCRYPT(cx, 0, kd, mn); | |
221 | ctx->m = GM_KEY(ctx->mc, kd, mn); | |
222 | return (0); | |
223 | } | |
224 | ||
225 | static size_t gencomp_overhead(bulk *b) | |
226 | { | |
227 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
228 | return (ctx->cc->blksz + ctx->mc->hashsz); } | |
229 | ||
230 | static void gencomp_destroy(bulk *b) | |
231 | { | |
232 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
233 | ||
234 | GC_DESTROY(ctx->c); | |
235 | GC_DESTROY(ctx->m); | |
236 | xfree(ctx->t); | |
237 | DESTROY(ctx); | |
238 | } | |
239 | ||
240 | static const char *gencomp_encdoit(bulk *b, uint32 seq, buf *bb, | |
241 | const void *p, size_t sz) | |
242 | { | |
243 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
244 | octet *tag, *ct; | |
245 | ghash *h = GM_INIT(ctx->m); | |
246 | ||
247 | GH_HASHU32(h, seq); | |
248 | if (ctx->cc->blksz) { | |
249 | GC_ENCRYPT(ctx->cx, 0, ctx->t, ctx->cc->blksz); | |
250 | GC_SETIV(ctx->c, ctx->t); | |
251 | } | |
252 | tag = buf_get(bb, ctx->mc->hashsz); assert(tag); | |
253 | ct = buf_get(bb, sz); assert(ct); | |
254 | GC_ENCRYPT(ctx->c, p, ct, sz); | |
255 | GH_HASH(h, ct, sz); | |
256 | GH_DONE(h, tag); | |
257 | GH_DESTROY(h); | |
258 | return (0); | |
259 | } | |
260 | ||
261 | static const char *gencomp_decdoit(bulk *b, uint32 seq, buf *bb, | |
262 | const void *p, size_t sz) | |
263 | { | |
264 | gencomp_encctx *ctx = (gencomp_encctx *)b; | |
265 | buf bin; | |
266 | const octet *tag, *ct; | |
267 | octet *pt; | |
268 | ghash *h; | |
269 | int ok; | |
270 | ||
271 | buf_init(&bin, (/*unconst*/ void *)p, sz); | |
272 | if ((tag = buf_get(&bin, ctx->mc->hashsz)) == 0) return ("no tag"); | |
273 | ct = BCUR(&bin); sz = BLEFT(&bin); | |
274 | pt = buf_get(bb, sz); assert(pt); | |
275 | ||
276 | h = GM_INIT(ctx->m); | |
277 | GH_HASHU32(h, seq); | |
278 | GH_HASH(h, ct, sz); | |
279 | ok = ct_memeq(tag, GH_DONE(h, 0), ctx->mc->hashsz); | |
280 | GH_DESTROY(h); | |
281 | if (!ok) return ("authentication failure"); | |
282 | ||
283 | if (ctx->cc->blksz) { | |
284 | GC_ENCRYPT(ctx->cx, 0, ctx->t, ctx->cc->blksz); | |
285 | GC_SETIV(ctx->c, ctx->t); | |
286 | } | |
287 | GC_DECRYPT(ctx->c, ct, pt, sz); | |
288 | return (0); | |
289 | } | |
290 | ||
291 | static const bulkops gencomp_encops = { | |
292 | gencomp_init, gencomp_setup, gencomp_overhead, | |
293 | gencomp_encdoit, gencomp_destroy | |
294 | }, gencomp_decops = { | |
295 | gencomp_init, gencomp_setup, gencomp_overhead, | |
296 | gencomp_decdoit, gencomp_destroy | |
297 | }; | |
298 | ||
299 | const struct bulktab bulktab[] = { | |
300 | { "gencomp", &gencomp_encops, &gencomp_decops }, | |
d9d419b0 | 301 | { "naclbox", &naclbox_encops, &naclbox_decops }, |
66ff643c MW |
302 | { 0, 0, 0 } |
303 | }; | |
304 | ||
5c3f75ec | 305 | /*----- Key encapsulation -------------------------------------------------*/ |
306 | ||
307 | /* --- RSA --- */ | |
308 | ||
309 | typedef struct rsa_encctx { | |
310 | kem k; | |
311 | rsa_pubctx rp; | |
312 | } rsa_encctx; | |
313 | ||
314 | static kem *rsa_encinit(key *k, void *kd) | |
315 | { | |
316 | rsa_encctx *re = CREATE(rsa_encctx); | |
317 | rsa_pubcreate(&re->rp, kd); | |
318 | return (&re->k); | |
319 | } | |
320 | ||
321 | static int rsa_encdoit(kem *k, dstr *d, ghash *h) | |
322 | { | |
323 | rsa_encctx *re = (rsa_encctx *)k; | |
324 | mp *x = mprand_range(MP_NEW, re->rp.rp->n, &rand_global, 0); | |
325 | mp *y = rsa_pubop(&re->rp, MP_NEW, x); | |
326 | size_t n = mp_octets(re->rp.rp->n); | |
327 | dstr_ensure(d, n); | |
328 | mp_storeb(x, d->buf, n); | |
329 | GH_HASH(h, d->buf, n); | |
330 | mp_storeb(y, d->buf, n); | |
331 | d->len += n; | |
332 | mp_drop(x); | |
333 | mp_drop(y); | |
334 | return (0); | |
335 | } | |
336 | ||
337 | static const char *rsa_lengthcheck(mp *n) | |
338 | { | |
339 | if (mp_bits(n) < 1020) return ("key too short"); | |
340 | return (0); | |
341 | } | |
342 | ||
343 | static const char *rsa_enccheck(kem *k) | |
344 | { | |
345 | rsa_encctx *re = (rsa_encctx *)k; | |
346 | const char *e; | |
347 | if ((e = rsa_lengthcheck(re->rp.rp->n)) != 0) return (e); | |
348 | return (0); | |
349 | } | |
350 | ||
351 | static void rsa_encdestroy(kem *k) | |
352 | { | |
353 | rsa_encctx *re = (rsa_encctx *)k; | |
354 | rsa_pubdestroy(&re->rp); | |
355 | DESTROY(re); | |
356 | } | |
357 | ||
358 | static const kemops rsa_encops = { | |
359 | rsa_pubfetch, sizeof(rsa_pub), | |
360 | rsa_encinit, rsa_encdoit, rsa_enccheck, rsa_encdestroy | |
361 | }; | |
362 | ||
363 | typedef struct rsa_decctx { | |
364 | kem k; | |
365 | rsa_privctx rp; | |
366 | } rsa_decctx; | |
367 | ||
368 | static kem *rsa_decinit(key *k, void *kd) | |
369 | { | |
370 | rsa_decctx *rd = CREATE(rsa_decctx); | |
371 | rsa_privcreate(&rd->rp, kd, &rand_global); | |
372 | return (&rd->k); | |
373 | } | |
374 | ||
375 | static int rsa_decdoit(kem *k, dstr *d, ghash *h) | |
376 | { | |
377 | rsa_decctx *rd = (rsa_decctx *)k; | |
378 | mp *x = mp_loadb(MP_NEW, d->buf, d->len); | |
379 | size_t n; | |
380 | char *p; | |
381 | ||
382 | if (MP_CMP(x, >=, rd->rp.rp->n)) { | |
383 | mp_drop(x); | |
384 | return (-1); | |
385 | } | |
386 | n = mp_octets(rd->rp.rp->n); | |
387 | p = xmalloc(n); | |
388 | x = rsa_privop(&rd->rp, x, x); | |
389 | mp_storeb(x, p, n); | |
390 | GH_HASH(h, p, n); | |
391 | mp_drop(x); | |
392 | xfree(p); | |
393 | return (0); | |
394 | } | |
395 | ||
396 | static const char *rsa_deccheck(kem *k) | |
397 | { | |
398 | rsa_decctx *rd = (rsa_decctx *)k; | |
399 | const char *e; | |
400 | if ((e = rsa_lengthcheck(rd->rp.rp->n)) != 0) return (e); | |
401 | return (0); | |
402 | } | |
403 | ||
404 | static void rsa_decdestroy(kem *k) | |
405 | { | |
406 | rsa_decctx *rd = (rsa_decctx *)k; | |
407 | rsa_privdestroy(&rd->rp); | |
408 | DESTROY(rd); | |
409 | } | |
410 | ||
411 | static const kemops rsa_decops = { | |
412 | rsa_privfetch, sizeof(rsa_priv), | |
413 | rsa_decinit, rsa_decdoit, rsa_deccheck, rsa_decdestroy | |
414 | }; | |
415 | ||
416 | /* --- DH and EC --- */ | |
417 | ||
418 | typedef struct dh_encctx { | |
419 | kem k; | |
420 | group *g; | |
421 | mp *x; | |
422 | ge *y; | |
423 | } dh_encctx; | |
424 | ||
45c0fd36 | 425 | static dh_encctx *dh_doinit(key *k, const gprime_param *gp, mp *y, |
3688eb75 | 426 | group *(*makegroup)(const gprime_param *), |
427 | const char *what) | |
5c3f75ec | 428 | { |
429 | dh_encctx *de = CREATE(dh_encctx); | |
430 | dstr t = DSTR_INIT; | |
431 | ||
432 | key_fulltag(k, &t); | |
3688eb75 | 433 | if ((de->g = makegroup(gp)) == 0) |
434 | die(EXIT_FAILURE, "bad %s group in key `%s'", what, t.buf); | |
5c3f75ec | 435 | de->x = MP_NEW; |
436 | de->y = G_CREATE(de->g); | |
437 | if (G_FROMINT(de->g, de->y, y)) | |
438 | die(EXIT_FAILURE, "bad public key `%s'", t.buf); | |
439 | dstr_destroy(&t); | |
440 | return (de); | |
441 | } | |
442 | ||
443 | static dh_encctx *ec_doinit(key *k, const char *cstr, const ec *y) | |
444 | { | |
445 | dh_encctx *de = CREATE(dh_encctx); | |
446 | ec_info ei; | |
447 | const char *e; | |
448 | dstr t = DSTR_INIT; | |
449 | ||
450 | key_fulltag(k, &t); | |
451 | if ((e = ec_getinfo(&ei, cstr)) != 0 || | |
452 | (de->g = group_ec(&ei)) == 0) | |
453 | die(EXIT_FAILURE, "bad elliptic curve spec in key `%s': %s", t.buf, e); | |
454 | de->x = MP_NEW; | |
455 | de->y = G_CREATE(de->g); | |
456 | if (G_FROMEC(de->g, de->y, y)) | |
457 | die(EXIT_FAILURE, "bad public curve point `%s'", t.buf); | |
458 | dstr_destroy(&t); | |
459 | return (de); | |
460 | } | |
461 | ||
462 | static kem *dh_encinit(key *k, void *kd) | |
463 | { | |
464 | dh_pub *dp = kd; | |
3688eb75 | 465 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_prime, "prime"); |
466 | return (&de->k); | |
467 | } | |
468 | ||
469 | static kem *bindh_encinit(key *k, void *kd) | |
470 | { | |
471 | dh_pub *dp = kd; | |
472 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_binary, "binary"); | |
5c3f75ec | 473 | return (&de->k); |
474 | } | |
475 | ||
476 | static kem *ec_encinit(key *k, void *kd) | |
477 | { | |
478 | ec_pub *ep = kd; | |
479 | dh_encctx *de = ec_doinit(k, ep->cstr, &ep->p); | |
480 | return (&de->k); | |
481 | } | |
482 | ||
483 | static int dh_encdoit(kem *k, dstr *d, ghash *h) | |
484 | { | |
485 | dh_encctx *de = (dh_encctx *)k; | |
486 | mp *r = mprand_range(MP_NEW, de->g->r, &rand_global, 0); | |
487 | ge *x = G_CREATE(de->g); | |
488 | ge *y = G_CREATE(de->g); | |
489 | size_t n = de->g->noctets; | |
490 | buf b; | |
45c0fd36 | 491 | |
5c3f75ec | 492 | G_EXP(de->g, x, de->g->g, r); |
493 | G_EXP(de->g, y, de->y, r); | |
494 | dstr_ensure(d, n); | |
495 | buf_init(&b, d->buf, n); | |
496 | G_TORAW(de->g, &b, y); | |
497 | GH_HASH(h, BBASE(&b), BLEN(&b)); | |
498 | buf_init(&b, d->buf, n); | |
499 | G_TORAW(de->g, &b, x); | |
500 | GH_HASH(h, BBASE(&b), BLEN(&b)); | |
501 | d->len += BLEN(&b); | |
502 | mp_drop(r); | |
503 | G_DESTROY(de->g, x); | |
504 | G_DESTROY(de->g, y); | |
505 | return (0); | |
506 | } | |
507 | ||
508 | static const char *dh_enccheck(kem *k) | |
509 | { | |
510 | dh_encctx *de = (dh_encctx *)k; | |
511 | const char *e; | |
512 | if ((e = G_CHECK(de->g, &rand_global)) != 0) | |
513 | return (0); | |
514 | if (group_check(de->g, de->y)) | |
515 | return ("public key not in subgroup"); | |
516 | return (0); | |
517 | } | |
518 | ||
519 | static void dh_encdestroy(kem *k) | |
520 | { | |
521 | dh_encctx *de = (dh_encctx *)k; | |
522 | G_DESTROY(de->g, de->y); | |
523 | mp_drop(de->x); | |
524 | G_DESTROYGROUP(de->g); | |
6f313264 | 525 | DESTROY(de); |
5c3f75ec | 526 | } |
527 | ||
528 | static const kemops dh_encops = { | |
529 | dh_pubfetch, sizeof(dh_pub), | |
530 | dh_encinit, dh_encdoit, dh_enccheck, dh_encdestroy | |
531 | }; | |
532 | ||
3688eb75 | 533 | static const kemops bindh_encops = { |
534 | dh_pubfetch, sizeof(dh_pub), | |
535 | bindh_encinit, dh_encdoit, dh_enccheck, dh_encdestroy | |
536 | }; | |
537 | ||
5c3f75ec | 538 | static const kemops ec_encops = { |
539 | ec_pubfetch, sizeof(ec_pub), | |
540 | ec_encinit, dh_encdoit, dh_enccheck, dh_encdestroy | |
541 | }; | |
542 | ||
543 | static kem *dh_decinit(key *k, void *kd) | |
544 | { | |
545 | dh_priv *dp = kd; | |
3688eb75 | 546 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_prime, "prime"); |
547 | de->x = MP_COPY(dp->x); | |
548 | return (&de->k); | |
549 | } | |
550 | ||
551 | static kem *bindh_decinit(key *k, void *kd) | |
552 | { | |
553 | dh_priv *dp = kd; | |
554 | dh_encctx *de = dh_doinit(k, &dp->dp, dp->y, group_binary, "binary"); | |
5c3f75ec | 555 | de->x = MP_COPY(dp->x); |
556 | return (&de->k); | |
557 | } | |
558 | ||
559 | static kem *ec_decinit(key *k, void *kd) | |
560 | { | |
561 | ec_priv *ep = kd; | |
562 | dh_encctx *de = ec_doinit(k, ep->cstr, &ep->p); | |
563 | de->x = MP_COPY(ep->x); | |
564 | return (&de->k); | |
565 | } | |
566 | ||
567 | static int dh_decdoit(kem *k, dstr *d, ghash *h) | |
568 | { | |
569 | dh_encctx *de = (dh_encctx *)k; | |
570 | ge *x = G_CREATE(de->g); | |
571 | size_t n = de->g->noctets; | |
572 | void *p = xmalloc(n); | |
573 | buf b; | |
574 | int rc = -1; | |
575 | ||
576 | buf_init(&b, d->buf, d->len); | |
577 | if (G_FROMRAW(de->g, &b, x) || group_check(de->g, x)) | |
578 | goto done; | |
579 | G_EXP(de->g, x, x, de->x); | |
580 | buf_init(&b, p, n); | |
581 | G_TORAW(de->g, &b, x); | |
582 | GH_HASH(h, BBASE(&b), BLEN(&b)); | |
583 | GH_HASH(h, d->buf, d->len); | |
584 | rc = 0; | |
585 | done: | |
586 | G_DESTROY(de->g, x); | |
587 | xfree(p); | |
588 | return (rc); | |
589 | } | |
590 | ||
591 | static const kemops dh_decops = { | |
592 | dh_privfetch, sizeof(dh_priv), | |
593 | dh_decinit, dh_decdoit, dh_enccheck, dh_encdestroy | |
594 | }; | |
595 | ||
3688eb75 | 596 | static const kemops bindh_decops = { |
597 | dh_privfetch, sizeof(dh_priv), | |
598 | bindh_decinit, dh_decdoit, dh_enccheck, dh_encdestroy | |
599 | }; | |
600 | ||
5c3f75ec | 601 | static const kemops ec_decops = { |
602 | ec_privfetch, sizeof(ec_priv), | |
603 | ec_decinit, dh_decdoit, dh_enccheck, dh_encdestroy | |
604 | }; | |
605 | ||
fc2d44af MW |
606 | /* --- X25519 --- */ |
607 | ||
608 | static kem *x25519_encinit(key *k, void *kd) { return (CREATE(kem)); } | |
609 | static void x25519_encdestroy(kem *k) { DESTROY(k); } | |
610 | ||
611 | static const char *x25519_enccheck(kem *k) | |
612 | { | |
613 | x25519_pub *kd = k->kd; | |
614 | ||
615 | if (kd->pub.sz != X25519_PUBSZ) | |
616 | return ("incorrect X25519 public key length"); | |
617 | return (0); | |
618 | } | |
619 | ||
620 | static int x25519_encdoit(kem *k, dstr *d, ghash *h) | |
621 | { | |
622 | octet t[X25519_KEYSZ], z[X25519_OUTSZ]; | |
623 | x25519_pub *kd = k->kd; | |
624 | ||
625 | rand_get(RAND_GLOBAL, t, sizeof(t)); | |
626 | dstr_ensure(d, X25519_PUBSZ); | |
627 | x25519((octet *)d->buf, t, x25519_base); | |
628 | x25519(z, t, kd->pub.k); | |
629 | d->len += X25519_PUBSZ; | |
630 | GH_HASH(h, d->buf, X25519_PUBSZ); | |
631 | GH_HASH(h, z, X25519_OUTSZ); | |
632 | return (0); | |
633 | } | |
634 | ||
635 | static const char *x25519_deccheck(kem *k) | |
636 | { | |
637 | x25519_priv *kd = k->kd; | |
638 | ||
639 | if (kd->priv.sz != X25519_KEYSZ) | |
640 | return ("incorrect X25519 private key length"); | |
641 | if (kd->pub.sz != X25519_PUBSZ) | |
642 | return ("incorrect X25519 public key length"); | |
643 | return (0); | |
644 | } | |
645 | ||
646 | static int x25519_decdoit(kem *k, dstr *d, ghash *h) | |
647 | { | |
648 | octet z[X25519_OUTSZ]; | |
649 | x25519_priv *kd = k->kd; | |
650 | int rc = -1; | |
651 | ||
652 | if (d->len != X25519_PUBSZ) goto done; | |
653 | x25519(z, kd->priv.k, (const octet *)d->buf); | |
654 | GH_HASH(h, d->buf, X25519_PUBSZ); | |
655 | GH_HASH(h, z, X25519_OUTSZ); | |
656 | rc = 0; | |
657 | done: | |
658 | return (rc); | |
659 | } | |
660 | ||
661 | static const kemops x25519_encops = { | |
662 | x25519_pubfetch, sizeof(x25519_pub), | |
663 | x25519_encinit, x25519_encdoit, x25519_enccheck, x25519_encdestroy | |
664 | }; | |
665 | ||
666 | static const kemops x25519_decops = { | |
667 | x25519_privfetch, sizeof(x25519_priv), | |
668 | x25519_encinit, x25519_decdoit, x25519_deccheck, x25519_encdestroy | |
669 | }; | |
670 | ||
02dfbd5b MW |
671 | /* --- Symmetric --- */ |
672 | ||
673 | typedef struct symm_ctx { | |
674 | kem k; | |
675 | key_packdef kp; | |
676 | key_bin kb; | |
677 | } symm_ctx; | |
678 | ||
679 | static kem *symm_init(key *k, void *kd) | |
680 | { | |
681 | symm_ctx *s; | |
682 | dstr d = DSTR_INIT; | |
683 | int err; | |
684 | ||
685 | s = CREATE(symm_ctx); | |
686 | ||
687 | key_fulltag(k, &d); | |
688 | s->kp.e = KENC_BINARY; | |
689 | s->kp.p = &s->kb; | |
690 | s->kp.kd = 0; | |
691 | ||
692 | if ((err = key_unpack(&s->kp, kd, &d)) != 0) { | |
693 | die(EXIT_FAILURE, "failed to unpack symmetric key `%s': %s", | |
694 | d.buf, key_strerror(err)); | |
695 | } | |
696 | dstr_destroy(&d); | |
697 | return (&s->k); | |
698 | } | |
699 | ||
700 | static int symm_decdoit(kem *k, dstr *d, ghash *h) | |
701 | { | |
702 | symm_ctx *s = (symm_ctx *)k; | |
703 | ||
704 | GH_HASH(h, s->kb.k, s->kb.sz); | |
705 | GH_HASH(h, d->buf, d->len); | |
706 | return (0); | |
707 | } | |
708 | ||
709 | static int symm_encdoit(kem *k, dstr *d, ghash *h) | |
710 | { | |
711 | dstr_ensure(d, h->ops->c->hashsz); | |
712 | d->len += h->ops->c->hashsz; | |
713 | rand_get(RAND_GLOBAL, d->buf, d->len); | |
714 | return (symm_decdoit(k, d, h)); | |
715 | } | |
716 | ||
717 | static const char *symm_check(kem *k) { return (0); } | |
718 | ||
719 | static void symm_destroy(kem *k) | |
720 | { symm_ctx *s = (symm_ctx *)k; key_unpackdone(&s->kp); } | |
721 | ||
722 | static const kemops symm_encops = { | |
723 | 0, 0, | |
724 | symm_init, symm_encdoit, symm_check, symm_destroy | |
725 | }; | |
726 | ||
727 | static const kemops symm_decops = { | |
728 | 0, 0, | |
729 | symm_init, symm_decdoit, symm_check, symm_destroy | |
730 | }; | |
731 | ||
5c3f75ec | 732 | /* --- The switch table --- */ |
733 | ||
c65df279 | 734 | const struct kemtab kemtab[] = { |
5c3f75ec | 735 | { "rsa", &rsa_encops, &rsa_decops }, |
736 | { "dh", &dh_encops, &dh_decops }, | |
3688eb75 | 737 | { "bindh", &bindh_encops, &bindh_decops }, |
5c3f75ec | 738 | { "ec", &ec_encops, &ec_decops }, |
fc2d44af | 739 | { "x25519", &x25519_encops, &x25519_decops }, |
02dfbd5b | 740 | { "symm", &symm_encops, &symm_decops }, |
5c3f75ec | 741 | { 0, 0, 0 } |
742 | }; | |
743 | ||
744 | /* --- @getkem@ --- * | |
745 | * | |
746 | * Arguments: @key *k@ = the key to load | |
747 | * @const char *app@ = application name | |
748 | * @int wantpriv@ = nonzero if we want to decrypt | |
66ff643c | 749 | * @bulk **bc@ = bulk crypto context to set up |
5c3f75ec | 750 | * |
751 | * Returns: A key-encapsulating thing. | |
752 | * | |
753 | * Use: Loads a key. | |
754 | */ | |
755 | ||
66ff643c | 756 | kem *getkem(key *k, const char *app, int wantpriv, bulk **bc) |
5c3f75ec | 757 | { |
66ff643c | 758 | const char *kalg, *halg = 0, *balg = 0; |
5c3f75ec | 759 | dstr d = DSTR_INIT; |
760 | dstr t = DSTR_INIT; | |
761 | size_t n; | |
762 | char *p = 0; | |
763 | const char *q; | |
764 | kem *kk; | |
765 | const struct kemtab *kt; | |
766 | const kemops *ko; | |
66ff643c MW |
767 | const struct bulktab *bt; |
768 | const bulkops *bo; | |
5c3f75ec | 769 | void *kd; |
770 | int e; | |
771 | key_packdef *kp; | |
772 | ||
773 | /* --- Setup stuff --- */ | |
774 | ||
775 | key_fulltag(k, &t); | |
776 | ||
777 | /* --- Get the KEM name --- * | |
778 | * | |
779 | * Take the attribute if it's there; otherwise use the key type. | |
780 | */ | |
781 | ||
782 | n = strlen(app); | |
783 | if ((q = key_getattr(0, k, "kem")) != 0) { | |
784 | dstr_puts(&d, q); | |
785 | p = d.buf; | |
786 | } else if (strncmp(k->type, app, n) == 0 && k->type[n] == '-') { | |
787 | dstr_puts(&d, k->type); | |
788 | p = d.buf + n + 1; | |
789 | } else | |
790 | die(EXIT_FAILURE, "no KEM for key `%s'", t.buf); | |
791 | kalg = p; | |
792 | ||
66ff643c | 793 | /* --- Grab the bulk encryption scheme --- * |
5c3f75ec | 794 | * |
795 | * Grab it from the KEM if it's there, but override it from the attribute. | |
796 | */ | |
797 | ||
798 | if (p && (p = strchr(p, '/')) != 0) { | |
799 | *p++ = 0; | |
66ff643c | 800 | balg = p; |
5c3f75ec | 801 | } |
66ff643c MW |
802 | if ((q = key_getattr(0, k, "bulk")) != 0) |
803 | balg = q; | |
5c3f75ec | 804 | |
805 | /* --- Grab the hash function --- */ | |
806 | ||
807 | if (p && (p = strchr(p, '/')) != 0) { | |
808 | *p++ = 0; | |
809 | halg = p; | |
810 | } | |
811 | if ((q = key_getattr(0, k, "hash")) != 0) | |
812 | halg = q; | |
813 | ||
814 | /* --- Instantiate the KEM --- */ | |
815 | ||
816 | for (kt = kemtab; kt->name; kt++) { | |
817 | if (strcmp(kt->name, kalg) == 0) | |
818 | goto k_found; | |
819 | } | |
820 | die(EXIT_FAILURE, "key encapsulation mechanism `%s' not found in key `%s'", | |
821 | kalg, t.buf); | |
822 | k_found:; | |
823 | ko = wantpriv ? kt->decops : kt->encops; | |
02dfbd5b MW |
824 | if (!ko->kf) { |
825 | kd = k->k; | |
826 | key_incref(kd); | |
78ec50fa | 827 | kp = 0; |
02dfbd5b MW |
828 | } else { |
829 | kd = xmalloc(ko->kdsz); | |
830 | kp = key_fetchinit(ko->kf, 0, kd); | |
831 | if ((e = key_fetch(kp, k)) != 0) { | |
832 | die(EXIT_FAILURE, "error fetching key `%s': %s", | |
833 | t.buf, key_strerror(e)); | |
834 | } | |
835 | } | |
5c3f75ec | 836 | kk = ko->init(k, kd); |
837 | kk->kp = kp; | |
838 | kk->ops = ko; | |
839 | kk->kd = kd; | |
840 | ||
66ff643c | 841 | /* --- Set up the bulk crypto --- */ |
5c3f75ec | 842 | |
843 | if (!halg) | |
66ff643c MW |
844 | kk->hc = &rmd160; |
845 | else if ((kk->hc = ghash_byname(halg)) == 0) { | |
5c3f75ec | 846 | die(EXIT_FAILURE, "hash algorithm `%s' not found in key `%s'", |
847 | halg, t.buf); | |
848 | } | |
849 | ||
5c3f75ec | 850 | dstr_reset(&d); |
851 | if ((q = key_getattr(0, k, "kdf")) == 0) { | |
66ff643c | 852 | dstr_putf(&d, "%s-mgf", kk->hc->name); |
5c3f75ec | 853 | q = d.buf; |
854 | } | |
66ff643c | 855 | if ((kk->cxc = gcipher_byname(q)) == 0) { |
5c3f75ec | 856 | die(EXIT_FAILURE, "encryption scheme (KDF) `%s' not found in key `%s'", |
857 | q, t.buf); | |
858 | } | |
45c0fd36 | 859 | |
66ff643c MW |
860 | if (!balg) |
861 | bt = bulktab; | |
862 | else { | |
863 | for (bt = bulktab, bo = 0; bt->name; bt++) { | |
864 | if (strcmp(balg, bt->name) == 0) | |
865 | { balg = 0; goto b_found; } | |
866 | n = strlen(bt->name); | |
867 | if (strncmp(balg, bt->name, n) == 0 && balg[n] == '-') | |
868 | { balg += n + 1; goto b_found; } | |
869 | } | |
870 | bt = bulktab; | |
871 | b_found:; | |
5c3f75ec | 872 | } |
66ff643c MW |
873 | bo = wantpriv ? bt->decops : bt->encops; |
874 | *bc = bo->init(k, balg, kk->hc->name); | |
875 | (*bc)->ops = bo; | |
5c3f75ec | 876 | |
877 | /* --- Tidy up --- */ | |
878 | ||
879 | dstr_destroy(&d); | |
880 | dstr_destroy(&t); | |
881 | return (kk); | |
882 | } | |
883 | ||
884 | /* --- @setupkem@ --- * | |
885 | * | |
886 | * Arguments: @kem *k@ = key-encapsulation thing | |
887 | * @dstr *d@ = key-encapsulation data | |
66ff643c | 888 | * @bulk *bc@ = bulk crypto context to set up |
5c3f75ec | 889 | * |
890 | * Returns: Zero on success, nonzero on failure. | |
891 | * | |
892 | * Use: Initializes all the various symmetric things from a KEM. | |
893 | */ | |
894 | ||
66ff643c | 895 | int setupkem(kem *k, dstr *d, bulk *bc) |
5c3f75ec | 896 | { |
897 | octet *kd; | |
66ff643c | 898 | size_t n; |
5c3f75ec | 899 | ghash *h; |
c65df279 | 900 | int rc = -1; |
5c3f75ec | 901 | |
66ff643c | 902 | h = GH_INIT(k->hc); |
5c3f75ec | 903 | if (k->ops->doit(k, d, h)) |
904 | goto done; | |
66ff643c | 905 | n = keysz(GH_CLASS(h)->hashsz, k->cxc->keysz); |
5c3f75ec | 906 | if (!n) |
907 | goto done; | |
908 | kd = GH_DONE(h, 0); | |
66ff643c MW |
909 | k->cx = GC_INIT(k->cxc, kd, n); |
910 | bc->ops->setup(bc, k->cx); | |
5c3f75ec | 911 | |
912 | rc = 0; | |
913 | done: | |
914 | GH_DESTROY(h); | |
915 | return (rc); | |
916 | } | |
917 | ||
918 | /* --- @freekem@ --- * | |
919 | * | |
920 | * Arguments: @kem *k@ = key-encapsulation thing | |
921 | * | |
922 | * Returns: --- | |
923 | * | |
924 | * Use: Frees up a key-encapsulation thing. | |
925 | */ | |
926 | ||
927 | void freekem(kem *k) | |
928 | { | |
02dfbd5b MW |
929 | if (!k->ops->kf) |
930 | key_drop(k->kd); | |
931 | else { | |
932 | key_fetchdone(k->kp); | |
933 | xfree(k->kd); | |
934 | } | |
66ff643c | 935 | GC_DESTROY(k->cx); |
5c3f75ec | 936 | k->ops->destroy(k); |
937 | } | |
938 | ||
939 | /*----- That's all, folks -------------------------------------------------*/ |