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1 | /* -*-c-*- |
2 | * |
52c03a2a |
3 | * $Id: keymgmt.c,v 1.4 2004/04/03 12:35:13 mdw Exp $ |
410c8acf |
4 | * |
5 | * Key loading and storing |
6 | * |
7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Trivial IP Encryption (TrIPE). |
13 | * |
14 | * TrIPE is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU General Public License as published by |
16 | * the Free Software Foundation; either version 2 of the License, or |
17 | * (at your option) any later version. |
18 | * |
19 | * TrIPE is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with TrIPE; if not, write to the Free Software Foundation, |
26 | * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | */ |
28 | |
29 | /*----- Revision history --------------------------------------------------* |
30 | * |
31 | * $Log: keymgmt.c,v $ |
52c03a2a |
32 | * Revision 1.4 2004/04/03 12:35:13 mdw |
33 | * Support elliptic curve key exchange. |
34 | * |
00e64b67 |
35 | * Revision 1.3 2001/06/22 19:40:36 mdw |
36 | * Support expiry of other peers' public keys. |
37 | * |
56814747 |
38 | * Revision 1.2 2001/06/19 22:07:09 mdw |
39 | * Cosmetic fixes. |
40 | * |
410c8acf |
41 | * Revision 1.1 2001/02/03 20:26:37 mdw |
42 | * Initial checkin. |
43 | * |
44 | */ |
45 | |
46 | /*----- Header files ------------------------------------------------------*/ |
47 | |
48 | #include "tripe.h" |
49 | |
50 | /*----- Global variables --------------------------------------------------*/ |
51 | |
52c03a2a |
52 | group *gg; |
53 | mp *kpriv; |
410c8acf |
54 | |
55 | /*----- Static variables --------------------------------------------------*/ |
56 | |
57 | static key_file *kf_pub; |
58 | static const char *kr_priv, *kr_pub, *tag_priv; |
59 | static fwatch w_priv, w_pub; |
60 | |
52c03a2a |
61 | /*----- Key groups --------------------------------------------------------*/ |
62 | |
63 | typedef struct kgops { |
64 | const char *ty; |
65 | const char *(*loadpriv)(key_data *, group **, mp **, dstr *); |
66 | const char *(*loadpub)(key_data *, group **, ge **, dstr *); |
67 | } kgops; |
68 | |
69 | /* --- Diffie-Hellman --- */ |
70 | |
71 | static const char *kgdh_priv(key_data *kd, group **g, mp **x, dstr *t) |
72 | { |
73 | key_packstruct kps[DH_PRIVFETCHSZ]; |
74 | key_packdef *kp; |
75 | dh_priv dp; |
76 | const char *e; |
77 | int rc; |
78 | |
79 | kp = key_fetchinit(dh_privfetch, kps, &dp); |
80 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
81 | e = key_strerror(rc); |
82 | goto done; |
83 | } |
84 | *g = group_prime(&dp.dp); |
85 | *x = MP_COPY(dp.x); |
86 | e = 0; |
87 | done: |
88 | key_fetchdone(kp); |
89 | return (e); |
90 | } |
91 | |
92 | static const char *kgdh_pub(key_data *kd, group **g, ge **p, dstr *t) |
93 | { |
94 | key_packstruct kps[DH_PUBFETCHSZ]; |
95 | key_packdef *kp; |
96 | dh_pub dp; |
97 | const char *e; |
98 | int rc; |
99 | |
100 | kp = key_fetchinit(dh_pubfetch, kps, &dp); |
101 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
102 | e = key_strerror(rc); |
103 | goto done; |
104 | } |
105 | *g = group_prime(&dp.dp); |
106 | *p = G_CREATE(*g); |
107 | if (G_FROMINT(*g, *p, dp.y)) { |
108 | e = "bad public value"; |
109 | goto done; |
110 | } |
111 | e = 0; |
112 | done: |
113 | key_fetchdone(kp); |
114 | return (e); |
115 | } |
116 | |
117 | static const kgops kgdh_ops = { "tripe-dh", kgdh_priv, kgdh_pub }; |
118 | |
119 | /* --- Elliptic curve --- */ |
120 | |
121 | static const char *kgec_priv(key_data *kd, group **g, mp **x, dstr *t) |
122 | { |
123 | key_packstruct kps[EC_PRIVFETCHSZ]; |
124 | key_packdef *kp; |
125 | ec_priv ep; |
126 | ec_info ei; |
127 | const char *e; |
128 | int rc; |
129 | |
130 | kp = key_fetchinit(ec_privfetch, kps, &ep); |
131 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
132 | e = key_strerror(rc); |
133 | goto done; |
134 | } |
135 | if ((e = ec_getinfo(&ei, ep.cstr)) != 0) |
136 | goto done; |
137 | *g = group_ec(&ei); |
138 | *x = MP_COPY(ep.x); |
139 | e = 0; |
140 | done: |
141 | key_fetchdone(kp); |
142 | return (e); |
143 | } |
144 | |
145 | static const char *kgec_pub(key_data *kd, group **g, ge **p, dstr *t) |
146 | { |
147 | key_packstruct kps[EC_PUBFETCHSZ]; |
148 | key_packdef *kp; |
149 | ec_pub ep; |
150 | ec_info ei; |
151 | const char *e; |
152 | int rc; |
153 | |
154 | kp = key_fetchinit(ec_pubfetch, kps, &ep); |
155 | if ((rc = key_unpack(kp, kd, t)) != 0) { |
156 | e = key_strerror(rc); |
157 | goto done; |
158 | } |
159 | if ((e = ec_getinfo(&ei, ep.cstr)) != 0) |
160 | goto done; |
161 | *g = group_ec(&ei); |
162 | *p = G_CREATE(*g); |
163 | if (G_FROMEC(*g, *p, &ep.p)) { |
164 | e = "bad public point"; |
165 | goto done; |
166 | } |
167 | e = 0; |
168 | done: |
169 | key_fetchdone(kp); |
170 | return (e); |
171 | } |
172 | |
173 | static const kgops kgec_ops = { "tripe-ec", kgec_priv, kgec_pub }; |
174 | |
175 | /* --- Table of supported key types --- */ |
176 | |
177 | static const kgops *kgtab[] = { &kgdh_ops, &kgec_ops, 0 }; |
178 | |
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179 | /*----- Main code ---------------------------------------------------------*/ |
180 | |
181 | /* --- @keymoan@ --- * |
182 | * |
56814747 |
183 | * Arguments: @const char *file@ = name of the file |
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184 | * @int line@ = line number in file |
185 | * @const char *msg@ = error message |
186 | * @void *p@ = argument pointer |
187 | * |
188 | * Returns: --- |
189 | * |
190 | * Use: Reports an error message about loading a key file. |
191 | */ |
192 | |
193 | static void keymoan(const char *file, int line, const char *msg, void *p) |
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194 | { a_warn("%s:%i: error: %s", file, line, msg); } |
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195 | |
196 | /* --- @loadpriv@ --- * |
197 | * |
198 | * Arguments: @dstr *d@ = string to write errors in |
410c8acf |
199 | * |
200 | * Returns: Zero if OK, nonzero on error. |
201 | * |
202 | * Use: Loads the private key from its keyfile. |
203 | */ |
204 | |
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205 | static int loadpriv(dstr *d) |
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206 | { |
207 | key_file kf; |
52c03a2a |
208 | key *k; |
209 | key_data *kd; |
210 | dstr t = DSTR_INIT; |
211 | group *g = 0; |
212 | mp *x = 0; |
213 | int rc = -1; |
214 | const kgops **ko; |
215 | const char *e; |
216 | |
217 | /* --- Open the private key file --- */ |
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218 | |
219 | if (key_open(&kf, kr_priv, KOPEN_READ, keymoan, 0)) { |
220 | dstr_putf(d, "error reading private keyring `%s': %s", |
221 | kr_priv, strerror(errno)); |
52c03a2a |
222 | goto done_0; |
223 | } |
224 | |
225 | /* --- Find the private key --- */ |
226 | |
227 | if (key_qtag(&kf, tag_priv, &t, &k, &kd)) { |
228 | dstr_putf(d, "private key `%s' not found in keyring `%s'", |
229 | tag_priv, kr_priv); |
230 | goto done_1; |
231 | } |
232 | |
233 | /* --- Look up the key type in the table --- */ |
234 | |
235 | for (ko = kgtab; *ko; ko++) { |
236 | if (strcmp((*ko)->ty, k->type) == 0) |
237 | goto tymatch; |
238 | } |
239 | dstr_putf(d, "private key `%s' has unknown type `%s'", t.buf, k->type); |
240 | goto done_1; |
241 | tymatch:; |
242 | |
243 | /* --- Load the key --- */ |
244 | |
245 | if ((e = (*ko)->loadpriv(kd, &g, &x, &t)) != 0) { |
246 | dstr_putf(d, "error reading private key `%s': %s", t.buf, e); |
247 | goto done_1; |
248 | } |
249 | |
250 | /* --- Check that the key is sensible --- */ |
251 | |
252 | if ((e = G_CHECK(g, &rand_global)) != 0) { |
253 | dstr_putf(d, "bad group in private key `%s': %s", t.buf, e); |
254 | goto done_1; |
255 | } |
256 | |
257 | /* --- Good, we're happy --- * |
258 | * |
259 | * Dodginess! We change the group over here, but don't free any old group |
260 | * elements. This assumes that the new group is basically the same as the |
261 | * old one, and will happily adopt the existing elements. If it isn't, |
262 | * then we lose badly. Check this, then. |
263 | */ |
264 | |
265 | if (gg) { |
266 | if (!group_samep(g, gg)) { |
267 | dstr_putf(d, "private key `%s' has different group", t.buf); |
268 | goto done_1; |
410c8acf |
269 | } |
52c03a2a |
270 | G_DESTROYGROUP(gg); |
410c8acf |
271 | } |
52c03a2a |
272 | if (kpriv) |
273 | mp_drop(kpriv); |
274 | |
275 | /* --- Dump out the group --- */ |
276 | |
277 | IF_TRACING(T_KEYMGMT, { |
278 | trace(T_KEYMGMT, "keymgmt: extracted private key `%s'", t.buf); |
279 | IF_TRACING(T_CRYPTO, { |
280 | trace(T_CRYPTO, "crypto: r = %s", mpstr(g->r)); |
281 | trace(T_CRYPTO, "crypto: h = %s", mpstr(g->h)); |
282 | trace(T_CRYPTO, "crypto: x = %s", mpstr(x)); |
283 | }) |
284 | }) |
285 | |
286 | /* --- Success! --- */ |
287 | |
288 | gg = g; g = 0; |
289 | kpriv = x; x = 0; |
290 | rc = 0; |
291 | |
292 | /* --- Tidy up --- */ |
293 | |
294 | done_1: |
295 | key_close(&kf); |
296 | done_0: |
297 | dstr_destroy(&t); |
298 | if (x) mp_drop(x); |
299 | if (g) G_DESTROYGROUP(g); |
410c8acf |
300 | return (rc); |
301 | } |
302 | |
303 | /* --- @loadpub@ --- * |
304 | * |
305 | * Arguments: @dstr *d@ = string to write errors to |
306 | * |
307 | * Returns: Zero if OK, nonzero on error. |
308 | * |
309 | * Use: Reloads the public keyring. |
310 | */ |
311 | |
312 | static int loadpub(dstr *d) |
313 | { |
314 | key_file *kf = CREATE(key_file); |
315 | |
316 | if (key_open(kf, kr_pub, KOPEN_READ, keymoan, 0)) { |
317 | dstr_putf(d, "error reading public keyring `%s': %s", |
318 | kr_pub, strerror(errno)); |
319 | DESTROY(kf); |
320 | return (-1); |
321 | } |
322 | kf_pub = kf; |
323 | T( trace(T_KEYMGMT, "keymgmt: loaded public keyring `%s'", kr_pub); ) |
324 | return (0); |
325 | } |
326 | |
327 | /* --- @km_interval@ --- * |
328 | * |
329 | * Arguments: --- |
330 | * |
331 | * Returns: Zero if OK, nonzero to force reloading of keys. |
332 | * |
333 | * Use: Called on the interval timer to perform various useful jobs. |
334 | */ |
335 | |
336 | int km_interval(void) |
337 | { |
338 | dstr d = DSTR_INIT; |
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339 | key_file *kf; |
340 | int reload = 0; |
341 | |
342 | /* --- Check the private key first --- */ |
343 | |
344 | if (fwatch_update(&w_priv, kr_priv)) { |
345 | T( trace(T_KEYMGMT, "keymgmt: private keyring updated: reloading..."); ) |
346 | DRESET(&d); |
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347 | if (loadpriv(&d)) |
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348 | a_warn("%s -- ignoring changes", d.buf); |
52c03a2a |
349 | else |
410c8acf |
350 | reload = 1; |
410c8acf |
351 | } |
352 | |
353 | /* --- Now check the public keys --- */ |
354 | |
355 | if (fwatch_update(&w_pub, kr_pub)) { |
356 | T( trace(T_KEYMGMT, "keymgmt: public keyring updated: reloading..."); ) |
357 | kf = kf_pub; |
358 | DRESET(&d); |
359 | if (loadpub(&d)) |
360 | a_warn("%s -- ignoring changes", d.buf); |
361 | else { |
362 | reload = 1; |
363 | key_close(kf); |
364 | DESTROY(kf); |
365 | } |
366 | } |
367 | |
368 | /* --- Done --- */ |
369 | |
370 | return (reload); |
371 | } |
372 | |
373 | /* --- @km_init@ --- * |
374 | * |
375 | * Arguments: @const char *priv@ = private keyring file |
376 | * @const char *pub@ = public keyring file |
377 | * @const char *tag@ = tag to load |
378 | * |
379 | * Returns: --- |
380 | * |
381 | * Use: Initializes, and loads the private key. |
382 | */ |
383 | |
384 | void km_init(const char *priv, const char *pub, const char *tag) |
385 | { |
386 | dstr d = DSTR_INIT; |
387 | |
388 | kr_priv = priv; |
389 | kr_pub = pub; |
390 | tag_priv = tag; |
391 | fwatch_init(&w_priv, kr_priv); |
392 | fwatch_init(&w_pub, kr_pub); |
393 | |
394 | DRESET(&d); |
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395 | if (loadpriv(&d)) |
410c8acf |
396 | die(EXIT_FAILURE, "%s", d.buf); |
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397 | if (loadpub(&d)) |
398 | die(EXIT_FAILURE, "%s", d.buf); |
399 | } |
400 | |
401 | /* --- @km_getpubkey@ --- * |
402 | * |
403 | * Arguments: @const char *tag@ = public key tag to load |
52c03a2a |
404 | * @ge *kpub@ = where to put the public key |
00e64b67 |
405 | * @time_t *t_exp@ = where to put the expiry time |
410c8acf |
406 | * |
407 | * Returns: Zero if OK, nonzero if it failed. |
408 | * |
409 | * Use: Fetches a public key from the keyring. |
410 | */ |
411 | |
52c03a2a |
412 | int km_getpubkey(const char *tag, ge *kpub, time_t *t_exp) |
410c8acf |
413 | { |
00e64b67 |
414 | key *k; |
52c03a2a |
415 | key_data *kd; |
416 | dstr t = DSTR_INIT; |
417 | const kgops **ko; |
418 | const char *e; |
419 | group *g = 0; |
420 | ge *p = 0; |
421 | int rc = -1; |
422 | |
423 | /* --- Find the key --- */ |
424 | |
425 | if (key_qtag(kf_pub, tag, &t, &k, &kd)) { |
426 | a_warn("private key `%s' not found in keyring `%s'", tag_priv, kr_priv); |
427 | goto done; |
428 | } |
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429 | |
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430 | /* --- Look up the key type in the table --- */ |
431 | |
432 | for (ko = kgtab; *ko; ko++) { |
433 | if (strcmp((*ko)->ty, k->type) == 0) |
434 | goto tymatch; |
435 | } |
436 | a_warn("public key `%s' has unknown type `%s'", t.buf, k->type); |
437 | goto done; |
438 | tymatch:; |
439 | |
440 | /* --- Load the key --- */ |
441 | |
442 | if ((e = (*ko)->loadpub(kd, &g, &p, &t)) != 0) { |
443 | a_warn("error reading public key `%s': %s", t.buf, e); |
444 | goto done; |
445 | } |
446 | |
447 | /* --- Ensure that the group is correct --- * |
448 | * |
449 | * Dodginess! We assume that if this works, our global group is willing to |
450 | * adopt this public element. Probably reasonable. |
451 | */ |
452 | |
453 | if (!group_samep(gg, g)) { |
454 | a_warn("public key `%s' has incorrect group", t.buf); |
455 | goto done; |
456 | } |
457 | |
458 | /* --- Check the public group element --- */ |
459 | |
460 | if (group_check(gg, p)) { |
461 | a_warn("public key `%s' has bad public group element", t.buf); |
462 | goto done; |
410c8acf |
463 | } |
52c03a2a |
464 | |
465 | /* --- Dump the public key --- */ |
466 | |
410c8acf |
467 | IF_TRACING(T_KEYMGMT, { |
52c03a2a |
468 | trace(T_KEYMGMT, "keymgmt: extracted public key `%s'", t.buf); |
469 | trace(T_CRYPTO, "crypto: p = %s", gestr(gg, p)); |
410c8acf |
470 | }) |
52c03a2a |
471 | |
472 | /* --- OK, accept the public key --- */ |
473 | |
00e64b67 |
474 | *t_exp = k->exp; |
52c03a2a |
475 | G_COPY(gg, kpub, p); |
476 | rc = 0; |
477 | |
478 | /* --- Tidy up --- */ |
479 | |
480 | done: |
481 | if (p) G_DESTROY(g, p); |
482 | if (g) G_DESTROYGROUP(g); |
483 | dstr_destroy(&t); |
484 | return (rc); |
410c8acf |
485 | } |
486 | |
487 | /*----- That's all, folks -------------------------------------------------*/ |