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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: key-text.c,v 1.6 2004/04/08 01:36:15 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 | |
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30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
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32 | #include <ctype.h> |
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33 | #include <stdlib.h> |
34 | #include <string.h> |
35 | |
36 | #include <mLib/base64.h> |
37 | #include <mLib/bits.h> |
38 | #include <mLib/dstr.h> |
39 | #include <mLib/sub.h> |
40 | #include <mLib/sym.h> |
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41 | #include <mLib/url.h> |
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42 | |
43 | #include "key-data.h" |
44 | #include "mp.h" |
45 | #include "mptext.h" |
46 | |
47 | /*----- Main code ---------------------------------------------------------*/ |
48 | |
49 | /* --- @key_read@ --- * |
50 | * |
51 | * Arguments: @const char *p@ = pointer to textual key representation |
52 | * @key_data *k@ = pointer to output block for key data |
53 | * @char **pp@ = where to store the end pointer |
54 | * |
55 | * Returns: Zero if all went well, nonzero if there was a problem. |
56 | * |
57 | * Use: Parses a textual key description. |
58 | */ |
59 | |
60 | int key_read(const char *p, key_data *k, char **pp) |
61 | { |
62 | unsigned e; |
63 | |
64 | /* --- Read the encoding type --- * |
65 | * |
66 | * The key format is `[FLAGS:]DATA'. If there is no encoding type |
67 | * named, assume that it's `binary' for backwards compatibility. |
68 | */ |
69 | |
70 | if (strchr(p, ':') == 0) |
71 | e = 0; |
72 | else { |
73 | char *q; |
74 | if (key_readflags(p, &q, &e, 0)) |
75 | return (-1); |
76 | p = q + 1; |
77 | } |
78 | |
79 | /* --- Now scan the data based on the encoding type --- */ |
80 | |
81 | k->e = e; |
82 | switch (e & KF_ENCMASK) { |
83 | |
84 | /* --- Binary encoding --- * |
85 | * |
86 | * Simply read out the Base64-encoded data. Since `,' and `]' are our |
87 | * delimeter characters, and they can't appear in Base64-encoded data, I |
88 | * can just do a simple search to find the end of the encoded data. |
89 | */ |
90 | |
91 | case KENC_BINARY: |
92 | case KENC_ENCRYPT: { |
93 | dstr d = DSTR_INIT; |
94 | base64_ctx b; |
95 | size_t sz = strcspn(p, ",]"); |
96 | |
97 | base64_init(&b); |
98 | base64_decode(&b, p, sz, &d); |
99 | base64_decode(&b, 0, 0, &d); |
100 | k->u.k.k = sub_alloc(d.len); |
101 | k->u.k.sz = d.len; |
102 | memcpy(k->u.k.k, d.buf, d.len); |
103 | dstr_destroy(&d); |
104 | p += sz; |
105 | } break; |
106 | |
107 | /* --- Multiprecision integer encoding --- * |
108 | * |
109 | * Multiprecision integers have a convenient reading function. |
110 | */ |
111 | |
112 | case KENC_MP: { |
113 | char *q; |
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114 | mp *m = mp_readstring(k->e & KF_BURN ? MP_NEWSEC : MP_NEW, p, &q, 0); |
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115 | if (!m) |
116 | return (-1); |
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117 | k->u.m = m; |
118 | p = q; |
119 | } break; |
120 | |
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121 | /* --- String encoding --- * |
122 | * |
123 | * We use form-urlencoding to ensure that evil characters don't get out. |
124 | */ |
125 | |
126 | case KENC_STRING: { |
127 | dstr d = DSTR_INIT; |
128 | size_t sz = strcspn(p, ",]"); |
129 | const char *l = p + sz; |
130 | unsigned int ch; |
131 | int x, n; |
132 | |
133 | while (p < l) { |
134 | switch (*p) { |
135 | case '+': |
136 | DPUTC(&d, ' '); break; |
137 | case '%': |
138 | x = sscanf(p + 1, "%2x%n", &ch, &n); |
139 | if (x == 1) { DPUTC(&d, ch); p += n; break; } |
140 | default: |
141 | DPUTC(&d, *p); break; |
142 | } |
143 | p++; |
144 | } |
145 | DPUTZ(&d); |
146 | k->u.p = xstrdup(d.buf); |
147 | dstr_destroy(&d); |
148 | } break; |
149 | |
150 | /* --- Elliptic curve encoding --- * |
151 | * |
152 | * Again, we have a convenient function. Assume for now that points |
153 | * aren't secret. (Reasonably safe.) |
154 | */ |
155 | |
156 | case KENC_EC: { |
157 | qd_parse qd; |
158 | qd.p = p; |
159 | qd.e = 0; |
160 | EC_CREATE(&k->u.e); |
161 | if (!ec_ptparse(&qd, &k->u.e)) |
162 | return (-1); |
163 | p = qd.p; |
164 | } break; |
165 | |
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166 | /* --- Structured information encoding --- * |
167 | * |
168 | * The format for structured key data is `[NAME=KEY,...]', where the |
169 | * brackets are part of the syntax. Structured keys have no flags apart |
170 | * from the encoding. |
171 | * |
172 | * The binary encoding only allows names up to 255 bytes long. Check for |
173 | * this here. |
174 | */ |
175 | |
176 | case KENC_STRUCT: { |
177 | dstr d = DSTR_INIT; |
178 | char *q; |
179 | |
180 | /* --- Read the opening bracket --- */ |
181 | |
182 | k->e &= KF_ENCMASK; |
183 | if (*p != '[') |
184 | return (-1); |
185 | p++; |
186 | sym_create(&k->u.s); |
187 | |
188 | /* --- Read named key subparts --- */ |
189 | |
190 | for (;;) { |
191 | size_t sz; |
192 | key_struct *ks; |
193 | |
194 | /* --- Stop if there's a close-bracket --- * |
195 | * |
196 | * This allows `[]' to be an empty structured key, which is good. It |
197 | * also makes `[foo=enc:bar,]' legal, and that's less good but I can |
198 | * live with it. |
199 | */ |
200 | |
201 | if (*p == ']') |
202 | break; |
203 | |
204 | /* --- Read the name out and check the length --- */ |
205 | |
206 | if ((q = strchr(p, '=')) == 0) |
207 | goto fail; |
208 | sz = q - p; |
209 | if (sz >= 256) |
210 | goto fail; |
211 | DRESET(&d); |
212 | DPUTM(&d, p, sz); |
213 | DPUTZ(&d); |
214 | |
215 | /* --- Add an appropriate block to the key table --- * |
216 | * |
217 | * Simply destroy old data if there's already a match. |
218 | */ |
219 | |
220 | { |
221 | unsigned f; |
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222 | ks = sym_find(&k->u.s, d.buf, d.len, sizeof(*ks), &f); |
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223 | if (f) |
224 | key_destroy(&ks->k); |
225 | } |
226 | |
227 | /* --- Read the key data for the subkey --- */ |
228 | |
229 | if (key_read(q + 1, &ks->k, &q)) { |
230 | sym_remove(&k->u.s, ks); |
231 | goto fail; |
232 | } |
233 | p = q; |
234 | |
235 | /* --- Read the comma or close-bracket --- */ |
236 | |
237 | if (*p == ']') |
238 | break; |
239 | else if (*p == ',') |
240 | p++; |
241 | else |
242 | goto fail; |
243 | } |
244 | |
245 | /* --- Step past the close bracket --- */ |
246 | |
247 | p++; |
248 | dstr_destroy(&d); |
249 | break; |
250 | |
251 | /* --- Tidy up after a failure --- */ |
252 | |
253 | fail: |
254 | dstr_destroy(&d); |
255 | key_destroy(k); |
256 | return (-1); |
257 | } break; |
258 | |
259 | /* --- Anything else is unknown --- */ |
260 | |
261 | default: |
262 | return (-1); |
263 | } |
264 | |
265 | /* --- Return the end pointer --- */ |
266 | |
267 | if (pp) |
268 | *pp = (char *)p; |
269 | return (0); |
270 | } |
271 | |
272 | /* --- @key_write@ --- * |
273 | * |
274 | * Arguments: @key_data *k@ = pointer to key data |
275 | * @dstr *d@ = destination string to write on |
276 | * @const key_filter *kf@ = pointer to key selection block |
277 | * |
278 | * Returns: Nonzero if an item was actually written. |
279 | * |
280 | * Use: Writes a key in a textual encoding. |
281 | */ |
282 | |
283 | int key_write(key_data *k, dstr *d, const key_filter *kf) |
284 | { |
285 | int rc = 0; |
286 | if (!KEY_MATCH(k, kf)) |
287 | return (0); |
288 | switch (k->e & KF_ENCMASK) { |
289 | case KENC_BINARY: |
290 | case KENC_ENCRYPT: { |
291 | base64_ctx b; |
292 | |
293 | if ((k->e & KF_ENCMASK) == KENC_BINARY) |
294 | key_writeflags(k->e, d); |
295 | else |
296 | DPUTS(d, "encrypt,secret"); |
297 | DPUTC(d, ':'); |
298 | base64_init(&b); |
299 | b.indent = ""; |
300 | b.maxline = 0; |
301 | base64_encode(&b, k->u.k.k, k->u.k.sz, d); |
302 | base64_encode(&b, 0, 0, d); |
303 | rc = 1; |
304 | } break; |
305 | case KENC_MP: |
306 | key_writeflags(k->e, d); |
307 | DPUTC(d, ':'); |
308 | mp_writedstr(k->u.m, d, 10); |
309 | rc = 1; |
310 | break; |
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311 | case KENC_STRING: { |
312 | const char *p = k->u.p; |
313 | key_writeflags(k->e, d); |
314 | DPUTC(d, ':'); |
315 | while (*p) { |
316 | if (*p == ' ') DPUTC(d, '+'); |
317 | else if (!isalnum((unsigned char)*p)) dstr_putf(d, "%%%02x", *p); |
318 | else DPUTC(d, *p); |
319 | p++; |
320 | } |
321 | rc = 1; |
322 | } break; |
323 | case KENC_EC: |
324 | key_writeflags(k->e, d); |
325 | DPUTS(d, ":0x"); mp_writedstr(k->u.e.x, d, 16); |
326 | DPUTS(d, ",0x"); mp_writedstr(k->u.e.y, d, 16); |
327 | rc = 1; |
328 | break; |
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329 | case KENC_STRUCT: { |
330 | sym_iter i; |
331 | key_struct *ks; |
332 | char del = 0; |
333 | size_t n = d->len; |
334 | |
335 | DPUTS(d, "struct:["); |
336 | for (sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; ) { |
337 | size_t o = d->len; |
338 | if (del) |
339 | DPUTC(d, del); |
340 | DPUTS(d, SYM_NAME(ks)); |
341 | DPUTC(d, '='); |
342 | if (!key_write(&ks->k, d, kf)) |
343 | d->len = o; |
344 | else { |
345 | del = ','; |
346 | rc = 1; |
347 | } |
348 | } |
349 | if (!rc) |
350 | d->len = n; |
351 | else |
352 | DPUTC(d, ']'); |
353 | } break; |
354 | } |
355 | DPUTZ(d); |
356 | |
357 | return (rc); |
358 | } |
359 | |
360 | /*----- That's all, folks -------------------------------------------------*/ |