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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: key-binary.c,v 1.4 2004/03/28 01:58:47 mdw Exp $ |
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4 | * |
5 | * Key binary 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-binary.c,v $ |
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33 | * Revision 1.4 2004/03/28 01:58:47 mdw |
34 | * Generate, store and retreive elliptic curve keys. |
35 | * |
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36 | * Revision 1.3 2001/02/03 11:57:00 mdw |
37 | * Track mLib change: symbols no longer need to include a terminating |
38 | * null. |
39 | * |
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40 | * Revision 1.2 2000/06/17 11:25:20 mdw |
41 | * Use secure memory interface from MP library. |
42 | * |
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43 | * Revision 1.1 2000/02/12 18:21:02 mdw |
44 | * Overhaul of key management (again). |
45 | * |
46 | */ |
47 | |
48 | /*----- Header files ------------------------------------------------------*/ |
49 | |
50 | #include <stdlib.h> |
51 | #include <string.h> |
52 | |
53 | #include <mLib/bits.h> |
54 | #include <mLib/dstr.h> |
55 | #include <mLib/sub.h> |
56 | #include <mLib/sym.h> |
57 | |
58 | #include "key-data.h" |
59 | #include "mp.h" |
60 | #include "mptext.h" |
61 | |
62 | /*----- Main code ---------------------------------------------------------*/ |
63 | |
64 | /* --- @key_decode@ --- * |
65 | * |
66 | * Arguments: @const void *p@ = pointer to buffer to read |
67 | * @size_t sz@ = size of the buffer |
68 | * @key_data *k@ = pointer to key data block to write to |
69 | * |
70 | * Returns: Zero if everything worked, nonzero otherwise. |
71 | * |
72 | * Use: Decodes a binary representation of a key. |
73 | */ |
74 | |
75 | int key_decode(const void *p, size_t sz, key_data *k) |
76 | { |
77 | const octet *q = p; |
78 | size_t psz; |
79 | unsigned e; |
80 | |
81 | /* --- Parse the header information --- * |
82 | * |
83 | * Make sure the size matches external reality. Security holes have been |
84 | * known to creep in without this sort of check. (No, this isn't an after- |
85 | * the-fact patch-up.) |
86 | */ |
87 | |
88 | e = LOAD16(q); |
89 | psz = LOAD16(q + 2); |
90 | if (psz + 4 > sz) |
91 | return (-1); |
92 | k->e = e; |
93 | |
94 | /* --- Now decide what to do --- */ |
95 | |
96 | switch (e & KF_ENCMASK) { |
97 | |
98 | /* --- Plain binary data --- */ |
99 | |
100 | case KENC_BINARY: |
101 | case KENC_ENCRYPT: |
102 | k->u.k.k = sub_alloc(psz); |
103 | memcpy(k->u.k.k, q + 4, psz); |
104 | k->u.k.sz = psz; |
105 | break; |
106 | |
107 | /* --- Multiprecision integer data --- */ |
108 | |
109 | case KENC_MP: |
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110 | k->u.m = mp_loadb(k->e & KF_BURN ? MP_NEWSEC : MP_NEW, q + 4, psz); |
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111 | break; |
112 | |
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113 | /* --- String data --- */ |
114 | |
115 | case KENC_STRING: |
116 | k->u.p = xmalloc(sz + 1); |
117 | memcpy(k->u.p, q + 4, sz); |
118 | k->u.p[sz] = 0; |
119 | break; |
120 | |
121 | /* --- Elliptic curve point data --- */ |
122 | |
123 | case KENC_EC: { |
124 | size_t xsz, ysz; |
125 | if (sz < 2) return (-1); |
126 | xsz = LOAD16(q + 4); |
127 | if (sz < xsz + 4) return (-1); |
128 | ysz = LOAD16(q + 6 + xsz); |
129 | if (sz < xsz + ysz + 4) return (-1); |
130 | EC_CREATE(&k->u.e); |
131 | k->u.e.x = mp_loadb(MP_NEW, q + 6, xsz); |
132 | k->u.e.y = mp_loadb(MP_NEW, q + 6 + xsz, ysz); |
133 | } break; |
134 | |
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135 | /* --- Structured key data --- */ |
136 | |
137 | case KENC_STRUCT: { |
138 | dstr d = DSTR_INIT; |
139 | key_struct *ks; |
140 | unsigned f; |
141 | |
142 | if ((k->e & ~KF_ENCMASK) || (psz & 3)) |
143 | return (-1); |
144 | q += 4; |
145 | sym_create(&k->u.s); |
146 | |
147 | while (psz) { |
148 | |
149 | /* --- Read the tag string --- */ |
150 | |
151 | DRESET(&d); |
152 | sz = LOAD8(q); |
153 | if (sz >= psz) |
154 | goto fail; |
155 | DPUTM(&d, q + 1, sz); |
156 | DPUTZ(&d); |
157 | sz = (sz + 4) & ~3; |
158 | q += sz; psz -= sz; |
159 | |
160 | /* --- Read the encoding and size --- */ |
161 | |
162 | e = LOAD16(q); |
163 | sz = (LOAD16(q + 2) + 7) & ~3; |
164 | if (sz > psz) |
165 | goto fail; |
166 | |
167 | /* --- Create a table node and fill it in --- */ |
168 | |
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169 | ks = sym_find(&k->u.s, d.buf, d.len, sizeof(*ks), &f); |
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170 | if (f) |
171 | goto fail; |
172 | if (key_decode(q, sz, &ks->k)) { |
173 | sym_remove(&k->u.s, ks); |
174 | goto fail; |
175 | } |
176 | psz -= sz; |
177 | q += sz; |
178 | } |
179 | dstr_destroy(&d); |
180 | break; |
181 | |
182 | /* --- Tidy up after a failure --- */ |
183 | |
184 | fail: |
185 | dstr_destroy(&d); |
186 | key_destroy(k); |
187 | return (-1); |
188 | } break; |
189 | |
190 | /* --- Everything else --- */ |
191 | |
192 | default: |
193 | return (-1); |
194 | } |
195 | |
196 | /* --- OK, that was good --- */ |
197 | |
198 | return (0); |
199 | } |
200 | |
201 | /* --- @key_encode@ --- * |
202 | * |
203 | * Arguments: @key_data *k@ = pointer to key data block |
204 | * @dstr *d@ = pointer to destination string |
205 | * @const key_filter *kf@ = pointer to key selection block |
206 | * |
207 | * Returns: Nonzero if an item was actually written. |
208 | * |
209 | * Use: Encodes a key block as binary data. |
210 | */ |
211 | |
212 | int key_encode(key_data *k, dstr *d, const key_filter *kf) |
213 | { |
214 | int rc = 0; |
215 | if (!KEY_MATCH(k, kf)) |
216 | return (0); |
217 | switch (k->e & KF_ENCMASK) { |
218 | case KENC_BINARY: |
219 | case KENC_ENCRYPT: { |
220 | char *p; |
221 | |
222 | DENSURE(d, (k->u.k.sz + 7) & ~3); |
223 | p = d->buf + d->len; |
224 | STORE16(p, k->e); |
225 | STORE16(p + 2, k->u.k.sz); |
226 | d->len += 4; |
227 | DPUTM(d, k->u.k.k, k->u.k.sz); |
228 | rc = 1; |
229 | } break; |
230 | |
231 | case KENC_MP: { |
232 | char *p; |
233 | size_t sz = mp_octets(k->u.m); |
234 | |
235 | DENSURE(d, (sz + 7) & ~3); |
236 | p = d->buf + d->len; |
237 | STORE16(p, k->e); |
238 | STORE16(p + 2, sz); |
239 | mp_storeb(k->u.m, p + 4, sz); |
240 | d->len += sz + 4; |
241 | rc = 1; |
242 | } break; |
243 | |
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244 | case KENC_STRING: { |
245 | char *p; |
246 | size_t sz = strlen(k->u.p); |
247 | |
248 | DENSURE(d, (sz + 7) & ~3); |
249 | p = d->buf + d->len; |
250 | STORE16(p, k->e); |
251 | STORE16(p + 2, sz); |
252 | memcpy(p + 4, k->u.p, sz); |
253 | d->len += sz + 4; |
254 | rc = 1; |
255 | } break; |
256 | |
257 | case KENC_EC: { |
258 | char *p; |
259 | size_t xsz = mp_octets(k->u.e.x), ysz = mp_octets(k->u.e.y); |
260 | size_t sz = xsz + ysz + 4; |
261 | |
262 | DENSURE(d, (sz + 7) & ~3); |
263 | p = d->buf + d->len; |
264 | STORE16(p, k->e); |
265 | STORE16(p + 2, sz); |
266 | STORE16(p + 4, xsz); |
267 | mp_storeb(k->u.e.x, p + 6, xsz); |
268 | STORE16(p + 6 + xsz, ysz); |
269 | mp_storeb(k->u.e.y, p + 8 + xsz, ysz); |
270 | d->len += sz + 4; |
271 | rc = 1; |
272 | } break; |
273 | |
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274 | case KENC_STRUCT: { |
275 | size_t n; |
276 | char *p; |
277 | key_struct *ks; |
278 | sym_iter i; |
279 | |
280 | n = d->len; |
281 | DENSURE(d, 4); |
282 | p = d->buf + n; |
283 | STORE16(p, k->e & KF_ENCMASK); |
284 | d->len += 4; |
285 | for (sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; ) { |
286 | size_t o = d->len; |
287 | DENSURE(d, 1); |
288 | *(octet *)(d->buf + d->len++) = strlen(SYM_NAME(ks)); |
289 | DPUTS(d, SYM_NAME(ks)); |
290 | while (d->len & 3) |
291 | DPUTC(d, 0); |
292 | if (key_encode(&ks->k, d, kf)) |
293 | rc = 1; |
294 | else |
295 | d->len = o; |
296 | } |
297 | if (!rc) |
298 | d->len = n; |
299 | else { |
300 | p = d->buf + n + 2; |
301 | n = d->len - n - 4; |
302 | STORE16(p, n); |
303 | } |
304 | } break; |
305 | } |
306 | while (d->len & 3) |
307 | DPUTC(d, 0); |
308 | return (rc); |
309 | } |
310 | |
311 | /*----- That's all, folks -------------------------------------------------*/ |