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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: key-text.c,v 1.5 2004/04/01 13:42:48 mdw Exp $ |
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4 | * |
5 | * Key textual encoding |
6 | * |
7 | * (c) 1999 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb 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 Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: key-text.c,v $ |
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33 | * Revision 1.5 2004/04/01 13:42:48 mdw |
34 | * Missed off <ctype.h>\! |
35 | * |
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36 | * Revision 1.4 2004/03/28 01:58:47 mdw |
37 | * Generate, store and retreive elliptic curve keys. |
38 | * |
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39 | * Revision 1.3 2001/02/03 11:57:00 mdw |
40 | * Track mLib change: symbols no longer need to include a terminating |
41 | * null. |
42 | * |
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43 | * Revision 1.2 2000/06/17 11:27:20 mdw |
44 | * Use secure memory interface from MP library. |
45 | * |
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46 | * Revision 1.1 2000/02/12 18:21:02 mdw |
47 | * Overhaul of key management (again). |
48 | * |
49 | */ |
50 | |
51 | /*----- Header files ------------------------------------------------------*/ |
52 | |
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53 | #include <ctype.h> |
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54 | #include <stdlib.h> |
55 | #include <string.h> |
56 | |
57 | #include <mLib/base64.h> |
58 | #include <mLib/bits.h> |
59 | #include <mLib/dstr.h> |
60 | #include <mLib/sub.h> |
61 | #include <mLib/sym.h> |
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62 | #include <mLib/url.h> |
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63 | |
64 | #include "key-data.h" |
65 | #include "mp.h" |
66 | #include "mptext.h" |
67 | |
68 | /*----- Main code ---------------------------------------------------------*/ |
69 | |
70 | /* --- @key_read@ --- * |
71 | * |
72 | * Arguments: @const char *p@ = pointer to textual key representation |
73 | * @key_data *k@ = pointer to output block for key data |
74 | * @char **pp@ = where to store the end pointer |
75 | * |
76 | * Returns: Zero if all went well, nonzero if there was a problem. |
77 | * |
78 | * Use: Parses a textual key description. |
79 | */ |
80 | |
81 | int key_read(const char *p, key_data *k, char **pp) |
82 | { |
83 | unsigned e; |
84 | |
85 | /* --- Read the encoding type --- * |
86 | * |
87 | * The key format is `[FLAGS:]DATA'. If there is no encoding type |
88 | * named, assume that it's `binary' for backwards compatibility. |
89 | */ |
90 | |
91 | if (strchr(p, ':') == 0) |
92 | e = 0; |
93 | else { |
94 | char *q; |
95 | if (key_readflags(p, &q, &e, 0)) |
96 | return (-1); |
97 | p = q + 1; |
98 | } |
99 | |
100 | /* --- Now scan the data based on the encoding type --- */ |
101 | |
102 | k->e = e; |
103 | switch (e & KF_ENCMASK) { |
104 | |
105 | /* --- Binary encoding --- * |
106 | * |
107 | * Simply read out the Base64-encoded data. Since `,' and `]' are our |
108 | * delimeter characters, and they can't appear in Base64-encoded data, I |
109 | * can just do a simple search to find the end of the encoded data. |
110 | */ |
111 | |
112 | case KENC_BINARY: |
113 | case KENC_ENCRYPT: { |
114 | dstr d = DSTR_INIT; |
115 | base64_ctx b; |
116 | size_t sz = strcspn(p, ",]"); |
117 | |
118 | base64_init(&b); |
119 | base64_decode(&b, p, sz, &d); |
120 | base64_decode(&b, 0, 0, &d); |
121 | k->u.k.k = sub_alloc(d.len); |
122 | k->u.k.sz = d.len; |
123 | memcpy(k->u.k.k, d.buf, d.len); |
124 | dstr_destroy(&d); |
125 | p += sz; |
126 | } break; |
127 | |
128 | /* --- Multiprecision integer encoding --- * |
129 | * |
130 | * Multiprecision integers have a convenient reading function. |
131 | */ |
132 | |
133 | case KENC_MP: { |
134 | char *q; |
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135 | mp *m = mp_readstring(k->e & KF_BURN ? MP_NEWSEC : MP_NEW, p, &q, 0); |
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136 | if (!m) |
137 | return (-1); |
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138 | k->u.m = m; |
139 | p = q; |
140 | } break; |
141 | |
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142 | /* --- String encoding --- * |
143 | * |
144 | * We use form-urlencoding to ensure that evil characters don't get out. |
145 | */ |
146 | |
147 | case KENC_STRING: { |
148 | dstr d = DSTR_INIT; |
149 | size_t sz = strcspn(p, ",]"); |
150 | const char *l = p + sz; |
151 | unsigned int ch; |
152 | int x, n; |
153 | |
154 | while (p < l) { |
155 | switch (*p) { |
156 | case '+': |
157 | DPUTC(&d, ' '); break; |
158 | case '%': |
159 | x = sscanf(p + 1, "%2x%n", &ch, &n); |
160 | if (x == 1) { DPUTC(&d, ch); p += n; break; } |
161 | default: |
162 | DPUTC(&d, *p); break; |
163 | } |
164 | p++; |
165 | } |
166 | DPUTZ(&d); |
167 | k->u.p = xstrdup(d.buf); |
168 | dstr_destroy(&d); |
169 | } break; |
170 | |
171 | /* --- Elliptic curve encoding --- * |
172 | * |
173 | * Again, we have a convenient function. Assume for now that points |
174 | * aren't secret. (Reasonably safe.) |
175 | */ |
176 | |
177 | case KENC_EC: { |
178 | qd_parse qd; |
179 | qd.p = p; |
180 | qd.e = 0; |
181 | EC_CREATE(&k->u.e); |
182 | if (!ec_ptparse(&qd, &k->u.e)) |
183 | return (-1); |
184 | p = qd.p; |
185 | } break; |
186 | |
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187 | /* --- Structured information encoding --- * |
188 | * |
189 | * The format for structured key data is `[NAME=KEY,...]', where the |
190 | * brackets are part of the syntax. Structured keys have no flags apart |
191 | * from the encoding. |
192 | * |
193 | * The binary encoding only allows names up to 255 bytes long. Check for |
194 | * this here. |
195 | */ |
196 | |
197 | case KENC_STRUCT: { |
198 | dstr d = DSTR_INIT; |
199 | char *q; |
200 | |
201 | /* --- Read the opening bracket --- */ |
202 | |
203 | k->e &= KF_ENCMASK; |
204 | if (*p != '[') |
205 | return (-1); |
206 | p++; |
207 | sym_create(&k->u.s); |
208 | |
209 | /* --- Read named key subparts --- */ |
210 | |
211 | for (;;) { |
212 | size_t sz; |
213 | key_struct *ks; |
214 | |
215 | /* --- Stop if there's a close-bracket --- * |
216 | * |
217 | * This allows `[]' to be an empty structured key, which is good. It |
218 | * also makes `[foo=enc:bar,]' legal, and that's less good but I can |
219 | * live with it. |
220 | */ |
221 | |
222 | if (*p == ']') |
223 | break; |
224 | |
225 | /* --- Read the name out and check the length --- */ |
226 | |
227 | if ((q = strchr(p, '=')) == 0) |
228 | goto fail; |
229 | sz = q - p; |
230 | if (sz >= 256) |
231 | goto fail; |
232 | DRESET(&d); |
233 | DPUTM(&d, p, sz); |
234 | DPUTZ(&d); |
235 | |
236 | /* --- Add an appropriate block to the key table --- * |
237 | * |
238 | * Simply destroy old data if there's already a match. |
239 | */ |
240 | |
241 | { |
242 | unsigned f; |
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243 | ks = sym_find(&k->u.s, d.buf, d.len, sizeof(*ks), &f); |
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244 | if (f) |
245 | key_destroy(&ks->k); |
246 | } |
247 | |
248 | /* --- Read the key data for the subkey --- */ |
249 | |
250 | if (key_read(q + 1, &ks->k, &q)) { |
251 | sym_remove(&k->u.s, ks); |
252 | goto fail; |
253 | } |
254 | p = q; |
255 | |
256 | /* --- Read the comma or close-bracket --- */ |
257 | |
258 | if (*p == ']') |
259 | break; |
260 | else if (*p == ',') |
261 | p++; |
262 | else |
263 | goto fail; |
264 | } |
265 | |
266 | /* --- Step past the close bracket --- */ |
267 | |
268 | p++; |
269 | dstr_destroy(&d); |
270 | break; |
271 | |
272 | /* --- Tidy up after a failure --- */ |
273 | |
274 | fail: |
275 | dstr_destroy(&d); |
276 | key_destroy(k); |
277 | return (-1); |
278 | } break; |
279 | |
280 | /* --- Anything else is unknown --- */ |
281 | |
282 | default: |
283 | return (-1); |
284 | } |
285 | |
286 | /* --- Return the end pointer --- */ |
287 | |
288 | if (pp) |
289 | *pp = (char *)p; |
290 | return (0); |
291 | } |
292 | |
293 | /* --- @key_write@ --- * |
294 | * |
295 | * Arguments: @key_data *k@ = pointer to key data |
296 | * @dstr *d@ = destination string to write on |
297 | * @const key_filter *kf@ = pointer to key selection block |
298 | * |
299 | * Returns: Nonzero if an item was actually written. |
300 | * |
301 | * Use: Writes a key in a textual encoding. |
302 | */ |
303 | |
304 | int key_write(key_data *k, dstr *d, const key_filter *kf) |
305 | { |
306 | int rc = 0; |
307 | if (!KEY_MATCH(k, kf)) |
308 | return (0); |
309 | switch (k->e & KF_ENCMASK) { |
310 | case KENC_BINARY: |
311 | case KENC_ENCRYPT: { |
312 | base64_ctx b; |
313 | |
314 | if ((k->e & KF_ENCMASK) == KENC_BINARY) |
315 | key_writeflags(k->e, d); |
316 | else |
317 | DPUTS(d, "encrypt,secret"); |
318 | DPUTC(d, ':'); |
319 | base64_init(&b); |
320 | b.indent = ""; |
321 | b.maxline = 0; |
322 | base64_encode(&b, k->u.k.k, k->u.k.sz, d); |
323 | base64_encode(&b, 0, 0, d); |
324 | rc = 1; |
325 | } break; |
326 | case KENC_MP: |
327 | key_writeflags(k->e, d); |
328 | DPUTC(d, ':'); |
329 | mp_writedstr(k->u.m, d, 10); |
330 | rc = 1; |
331 | break; |
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332 | case KENC_STRING: { |
333 | const char *p = k->u.p; |
334 | key_writeflags(k->e, d); |
335 | DPUTC(d, ':'); |
336 | while (*p) { |
337 | if (*p == ' ') DPUTC(d, '+'); |
338 | else if (!isalnum((unsigned char)*p)) dstr_putf(d, "%%%02x", *p); |
339 | else DPUTC(d, *p); |
340 | p++; |
341 | } |
342 | rc = 1; |
343 | } break; |
344 | case KENC_EC: |
345 | key_writeflags(k->e, d); |
346 | DPUTS(d, ":0x"); mp_writedstr(k->u.e.x, d, 16); |
347 | DPUTS(d, ",0x"); mp_writedstr(k->u.e.y, d, 16); |
348 | rc = 1; |
349 | break; |
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350 | case KENC_STRUCT: { |
351 | sym_iter i; |
352 | key_struct *ks; |
353 | char del = 0; |
354 | size_t n = d->len; |
355 | |
356 | DPUTS(d, "struct:["); |
357 | for (sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; ) { |
358 | size_t o = d->len; |
359 | if (del) |
360 | DPUTC(d, del); |
361 | DPUTS(d, SYM_NAME(ks)); |
362 | DPUTC(d, '='); |
363 | if (!key_write(&ks->k, d, kf)) |
364 | d->len = o; |
365 | else { |
366 | del = ','; |
367 | rc = 1; |
368 | } |
369 | } |
370 | if (!rc) |
371 | d->len = n; |
372 | else |
373 | DPUTC(d, ']'); |
374 | } break; |
375 | } |
376 | DPUTZ(d); |
377 | |
378 | return (rc); |
379 | } |
380 | |
381 | /*----- That's all, folks -------------------------------------------------*/ |