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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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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 | |
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30 | /*----- Header files ------------------------------------------------------*/ |
31 | |
32 | #include <stdlib.h> |
33 | #include <string.h> |
34 | |
35 | #include <mLib/bits.h> |
36 | #include <mLib/dstr.h> |
37 | #include <mLib/sub.h> |
38 | #include <mLib/sym.h> |
39 | |
40 | #include "key-data.h" |
41 | #include "mp.h" |
42 | #include "mptext.h" |
43 | |
44 | /*----- Main code ---------------------------------------------------------*/ |
45 | |
46 | /* --- @key_decode@ --- * |
47 | * |
48 | * Arguments: @const void *p@ = pointer to buffer to read |
49 | * @size_t sz@ = size of the buffer |
50 | * @key_data *k@ = pointer to key data block to write to |
51 | * |
52 | * Returns: Zero if everything worked, nonzero otherwise. |
53 | * |
54 | * Use: Decodes a binary representation of a key. |
55 | */ |
56 | |
57 | int key_decode(const void *p, size_t sz, key_data *k) |
58 | { |
59 | const octet *q = p; |
60 | size_t psz; |
61 | unsigned e; |
62 | |
63 | /* --- Parse the header information --- * |
64 | * |
65 | * Make sure the size matches external reality. Security holes have been |
66 | * known to creep in without this sort of check. (No, this isn't an after- |
67 | * the-fact patch-up.) |
68 | */ |
69 | |
70 | e = LOAD16(q); |
71 | psz = LOAD16(q + 2); |
72 | if (psz + 4 > sz) |
73 | return (-1); |
74 | k->e = e; |
75 | |
76 | /* --- Now decide what to do --- */ |
77 | |
78 | switch (e & KF_ENCMASK) { |
79 | |
80 | /* --- Plain binary data --- */ |
81 | |
82 | case KENC_BINARY: |
83 | case KENC_ENCRYPT: |
84 | k->u.k.k = sub_alloc(psz); |
85 | memcpy(k->u.k.k, q + 4, psz); |
86 | k->u.k.sz = psz; |
87 | break; |
88 | |
89 | /* --- Multiprecision integer data --- */ |
90 | |
91 | case KENC_MP: |
99163693 |
92 | k->u.m = mp_loadb(k->e & KF_BURN ? MP_NEWSEC : MP_NEW, q + 4, psz); |
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93 | break; |
94 | |
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95 | /* --- String data --- */ |
96 | |
97 | case KENC_STRING: |
98 | k->u.p = xmalloc(sz + 1); |
99 | memcpy(k->u.p, q + 4, sz); |
100 | k->u.p[sz] = 0; |
101 | break; |
102 | |
103 | /* --- Elliptic curve point data --- */ |
104 | |
105 | case KENC_EC: { |
106 | size_t xsz, ysz; |
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107 | EC_CREATE(&k->u.e); |
108 | if (!sz) break; |
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109 | if (sz < 2) return (-1); |
110 | xsz = LOAD16(q + 4); |
111 | if (sz < xsz + 4) return (-1); |
112 | ysz = LOAD16(q + 6 + xsz); |
113 | if (sz < xsz + ysz + 4) return (-1); |
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114 | k->u.e.x = mp_loadb(MP_NEW, q + 6, xsz); |
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115 | k->u.e.y = mp_loadb(MP_NEW, q + 8 + xsz, ysz); |
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116 | } break; |
117 | |
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118 | /* --- Structured key data --- */ |
119 | |
120 | case KENC_STRUCT: { |
121 | dstr d = DSTR_INIT; |
122 | key_struct *ks; |
123 | unsigned f; |
124 | |
125 | if ((k->e & ~KF_ENCMASK) || (psz & 3)) |
126 | return (-1); |
127 | q += 4; |
128 | sym_create(&k->u.s); |
129 | |
130 | while (psz) { |
131 | |
132 | /* --- Read the tag string --- */ |
133 | |
134 | DRESET(&d); |
135 | sz = LOAD8(q); |
136 | if (sz >= psz) |
137 | goto fail; |
138 | DPUTM(&d, q + 1, sz); |
139 | DPUTZ(&d); |
140 | sz = (sz + 4) & ~3; |
141 | q += sz; psz -= sz; |
142 | |
143 | /* --- Read the encoding and size --- */ |
144 | |
145 | e = LOAD16(q); |
146 | sz = (LOAD16(q + 2) + 7) & ~3; |
147 | if (sz > psz) |
148 | goto fail; |
149 | |
150 | /* --- Create a table node and fill it in --- */ |
151 | |
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152 | ks = sym_find(&k->u.s, d.buf, d.len, sizeof(*ks), &f); |
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153 | if (f) |
154 | goto fail; |
155 | if (key_decode(q, sz, &ks->k)) { |
156 | sym_remove(&k->u.s, ks); |
157 | goto fail; |
158 | } |
159 | psz -= sz; |
160 | q += sz; |
161 | } |
162 | dstr_destroy(&d); |
163 | break; |
164 | |
165 | /* --- Tidy up after a failure --- */ |
166 | |
167 | fail: |
168 | dstr_destroy(&d); |
169 | key_destroy(k); |
170 | return (-1); |
171 | } break; |
172 | |
173 | /* --- Everything else --- */ |
174 | |
175 | default: |
176 | return (-1); |
177 | } |
178 | |
179 | /* --- OK, that was good --- */ |
180 | |
181 | return (0); |
182 | } |
183 | |
184 | /* --- @key_encode@ --- * |
185 | * |
186 | * Arguments: @key_data *k@ = pointer to key data block |
187 | * @dstr *d@ = pointer to destination string |
188 | * @const key_filter *kf@ = pointer to key selection block |
189 | * |
190 | * Returns: Nonzero if an item was actually written. |
191 | * |
192 | * Use: Encodes a key block as binary data. |
193 | */ |
194 | |
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195 | static int ksbyname(const void *a, const void *b) { |
196 | key_struct *const *x = a, *const *y = b; |
197 | return (strcmp(SYM_NAME(*x), SYM_NAME(*y))); |
198 | } |
199 | |
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200 | int key_encode(key_data *k, dstr *d, const key_filter *kf) |
201 | { |
202 | int rc = 0; |
203 | if (!KEY_MATCH(k, kf)) |
204 | return (0); |
205 | switch (k->e & KF_ENCMASK) { |
206 | case KENC_BINARY: |
207 | case KENC_ENCRYPT: { |
208 | char *p; |
209 | |
210 | DENSURE(d, (k->u.k.sz + 7) & ~3); |
211 | p = d->buf + d->len; |
212 | STORE16(p, k->e); |
213 | STORE16(p + 2, k->u.k.sz); |
214 | d->len += 4; |
215 | DPUTM(d, k->u.k.k, k->u.k.sz); |
216 | rc = 1; |
217 | } break; |
218 | |
219 | case KENC_MP: { |
220 | char *p; |
221 | size_t sz = mp_octets(k->u.m); |
222 | |
223 | DENSURE(d, (sz + 7) & ~3); |
224 | p = d->buf + d->len; |
225 | STORE16(p, k->e); |
226 | STORE16(p + 2, sz); |
227 | mp_storeb(k->u.m, p + 4, sz); |
228 | d->len += sz + 4; |
229 | rc = 1; |
230 | } break; |
231 | |
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232 | case KENC_STRING: { |
233 | char *p; |
234 | size_t sz = strlen(k->u.p); |
235 | |
236 | DENSURE(d, (sz + 7) & ~3); |
237 | p = d->buf + d->len; |
238 | STORE16(p, k->e); |
239 | STORE16(p + 2, sz); |
240 | memcpy(p + 4, k->u.p, sz); |
241 | d->len += sz + 4; |
242 | rc = 1; |
243 | } break; |
244 | |
245 | case KENC_EC: { |
246 | char *p; |
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247 | size_t xsz = 0, ysz = 0; |
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248 | size_t sz; |
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249 | |
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250 | if (EC_ATINF(&k->u.e)) |
251 | sz = 0; |
252 | else { |
253 | xsz = mp_octets(k->u.e.x); |
254 | ysz = mp_octets(k->u.e.y); |
255 | sz = xsz + ysz + 4; |
256 | } |
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257 | DENSURE(d, (sz + 7) & ~3); |
258 | p = d->buf + d->len; |
259 | STORE16(p, k->e); |
260 | STORE16(p + 2, sz); |
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261 | if (!EC_ATINF(&k->u.e)) { |
262 | STORE16(p + 4, xsz); |
263 | mp_storeb(k->u.e.x, p + 6, xsz); |
264 | STORE16(p + 6 + xsz, ysz); |
265 | mp_storeb(k->u.e.y, p + 8 + xsz, ysz); |
266 | } |
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267 | d->len += sz + 4; |
268 | rc = 1; |
269 | } break; |
270 | |
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271 | case KENC_STRUCT: { |
272 | size_t n; |
273 | char *p; |
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274 | key_struct *ks, **ksv; |
275 | size_t nks, j; |
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276 | sym_iter i; |
277 | |
278 | n = d->len; |
279 | DENSURE(d, 4); |
280 | p = d->buf + n; |
281 | STORE16(p, k->e & KF_ENCMASK); |
282 | d->len += 4; |
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283 | |
284 | for (nks = 0, sym_mkiter(&i, &k->u.s); |
285 | (ks = sym_next(&i)) != 0; |
286 | nks++); |
287 | if (nks) { |
288 | ksv = xmalloc(nks * sizeof(*ksv)); |
289 | for (j = 0, sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; j++) |
290 | ksv[j] = ks; |
291 | qsort(ksv, nks, sizeof(*ksv), ksbyname); |
292 | for (j = 0; j < nks; j++) { |
293 | size_t o = d->len; |
294 | ks = ksv[j]; |
295 | DENSURE(d, 1); |
296 | *(octet *)(d->buf + d->len++) = strlen(SYM_NAME(ks)); |
297 | DPUTS(d, SYM_NAME(ks)); |
298 | while (d->len & 3) |
299 | DPUTC(d, 0); |
300 | if (key_encode(&ks->k, d, kf)) |
301 | rc = 1; |
302 | else |
303 | d->len = o; |
304 | } |
305 | xfree(ksv); |
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306 | } |
307 | if (!rc) |
308 | d->len = n; |
309 | else { |
310 | p = d->buf + n + 2; |
311 | n = d->len - n - 4; |
312 | STORE16(p, n); |
313 | } |
314 | } break; |
315 | } |
316 | while (d->len & 3) |
317 | DPUTC(d, 0); |
318 | return (rc); |
319 | } |
320 | |
321 | /*----- That's all, folks -------------------------------------------------*/ |