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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 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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18 | * |
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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. |
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23 | * |
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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 |
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50 | * |
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51 | * Returns: The newly-read key data, or null if it failed. |
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52 | * |
53 | * Use: Decodes a binary representation of a key. |
54 | */ |
55 | |
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56 | key_data *key_decode(const void *p, size_t sz) |
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57 | { |
58 | const octet *q = p; |
59 | size_t psz; |
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60 | key_data *kd; |
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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) |
ef13e9a4 |
73 | return (0); |
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74 | |
75 | /* --- Now decide what to do --- */ |
76 | |
77 | switch (e & KF_ENCMASK) { |
78 | |
79 | /* --- Plain binary data --- */ |
80 | |
81 | case KENC_BINARY: |
82 | case KENC_ENCRYPT: |
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83 | kd = key_newbinary(e, q + 4, psz); |
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84 | break; |
85 | |
86 | /* --- Multiprecision integer data --- */ |
87 | |
88 | case KENC_MP: |
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89 | kd = key_newmp(e, mp_loadb(e & KF_BURN ? MP_NEWSEC : MP_NEW, |
90 | q + 4, psz)); |
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91 | break; |
92 | |
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93 | /* --- String data --- */ |
94 | |
95 | case KENC_STRING: |
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96 | kd = key_newraw(e); |
97 | kd->u.p = xmalloc(sz + 1); |
98 | memcpy(kd->u.p, q + 4, sz); |
99 | kd->u.p[sz] = 0; |
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100 | break; |
101 | |
102 | /* --- Elliptic curve point data --- */ |
103 | |
104 | case KENC_EC: { |
105 | size_t xsz, ysz; |
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106 | kd = key_newraw(e); |
107 | EC_CREATE(&kd->u.e); |
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108 | if (!sz) break; |
ef13e9a4 |
109 | if (sz < 2) return (0); |
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110 | xsz = LOAD16(q + 4); |
ef13e9a4 |
111 | if (sz < xsz + 4) return (0); |
1ba83484 |
112 | ysz = LOAD16(q + 6 + xsz); |
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113 | if (sz < xsz + ysz + 4) return (0); |
114 | kd->u.e.x = mp_loadb(MP_NEW, q + 6, xsz); |
115 | kd->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; |
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122 | key_data *nkd; |
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123 | |
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124 | if ((e & ~KF_ENCMASK) || (psz & 3)) |
125 | return (0); |
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126 | q += 4; |
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127 | kd = key_newstruct(); |
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128 | |
129 | while (psz) { |
130 | |
131 | /* --- Read the tag string --- */ |
132 | |
133 | DRESET(&d); |
134 | sz = LOAD8(q); |
135 | if (sz >= psz) |
136 | goto fail; |
137 | DPUTM(&d, q + 1, sz); |
138 | DPUTZ(&d); |
139 | sz = (sz + 4) & ~3; |
140 | q += sz; psz -= sz; |
141 | |
142 | /* --- Read the encoding and size --- */ |
143 | |
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144 | sz = (LOAD16(q + 2) + 7) & ~3; |
145 | if (sz > psz) |
146 | goto fail; |
147 | |
148 | /* --- Create a table node and fill it in --- */ |
149 | |
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150 | if ((nkd = key_decode(q, sz)) == 0) |
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151 | goto fail; |
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152 | key_structsteal(kd, d.buf, nkd); |
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153 | psz -= sz; |
154 | q += sz; |
155 | } |
156 | dstr_destroy(&d); |
157 | break; |
158 | |
159 | /* --- Tidy up after a failure --- */ |
160 | |
161 | fail: |
162 | dstr_destroy(&d); |
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163 | key_drop(kd); |
164 | return (0); |
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165 | } break; |
166 | |
167 | /* --- Everything else --- */ |
168 | |
169 | default: |
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170 | return (0); |
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171 | } |
172 | |
173 | /* --- OK, that was good --- */ |
174 | |
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175 | kd->e = e; |
176 | return (kd); |
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177 | } |
178 | |
179 | /* --- @key_encode@ --- * |
180 | * |
181 | * Arguments: @key_data *k@ = pointer to key data block |
182 | * @dstr *d@ = pointer to destination string |
183 | * @const key_filter *kf@ = pointer to key selection block |
184 | * |
185 | * Returns: Nonzero if an item was actually written. |
186 | * |
187 | * Use: Encodes a key block as binary data. |
188 | */ |
189 | |
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190 | static int ksbyname(const void *a, const void *b) { |
191 | key_struct *const *x = a, *const *y = b; |
192 | return (strcmp(SYM_NAME(*x), SYM_NAME(*y))); |
193 | } |
194 | |
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195 | int key_encode(key_data *k, dstr *d, const key_filter *kf) |
196 | { |
197 | int rc = 0; |
198 | if (!KEY_MATCH(k, kf)) |
199 | return (0); |
200 | switch (k->e & KF_ENCMASK) { |
201 | case KENC_BINARY: |
202 | case KENC_ENCRYPT: { |
203 | char *p; |
204 | |
205 | DENSURE(d, (k->u.k.sz + 7) & ~3); |
206 | p = d->buf + d->len; |
207 | STORE16(p, k->e); |
208 | STORE16(p + 2, k->u.k.sz); |
209 | d->len += 4; |
210 | DPUTM(d, k->u.k.k, k->u.k.sz); |
211 | rc = 1; |
212 | } break; |
213 | |
214 | case KENC_MP: { |
215 | char *p; |
216 | size_t sz = mp_octets(k->u.m); |
217 | |
218 | DENSURE(d, (sz + 7) & ~3); |
219 | p = d->buf + d->len; |
220 | STORE16(p, k->e); |
221 | STORE16(p + 2, sz); |
222 | mp_storeb(k->u.m, p + 4, sz); |
223 | d->len += sz + 4; |
224 | rc = 1; |
225 | } break; |
226 | |
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227 | case KENC_STRING: { |
228 | char *p; |
229 | size_t sz = strlen(k->u.p); |
230 | |
231 | DENSURE(d, (sz + 7) & ~3); |
232 | p = d->buf + d->len; |
233 | STORE16(p, k->e); |
234 | STORE16(p + 2, sz); |
235 | memcpy(p + 4, k->u.p, sz); |
236 | d->len += sz + 4; |
237 | rc = 1; |
238 | } break; |
239 | |
240 | case KENC_EC: { |
241 | char *p; |
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242 | size_t xsz = 0, ysz = 0; |
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243 | size_t sz; |
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244 | |
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245 | if (EC_ATINF(&k->u.e)) |
246 | sz = 0; |
247 | else { |
248 | xsz = mp_octets(k->u.e.x); |
249 | ysz = mp_octets(k->u.e.y); |
250 | sz = xsz + ysz + 4; |
251 | } |
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252 | DENSURE(d, (sz + 7) & ~3); |
253 | p = d->buf + d->len; |
254 | STORE16(p, k->e); |
255 | STORE16(p + 2, sz); |
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256 | if (!EC_ATINF(&k->u.e)) { |
257 | STORE16(p + 4, xsz); |
258 | mp_storeb(k->u.e.x, p + 6, xsz); |
259 | STORE16(p + 6 + xsz, ysz); |
260 | mp_storeb(k->u.e.y, p + 8 + xsz, ysz); |
261 | } |
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262 | d->len += sz + 4; |
263 | rc = 1; |
264 | } break; |
265 | |
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266 | case KENC_STRUCT: { |
267 | size_t n; |
268 | char *p; |
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269 | key_struct *ks, **ksv; |
270 | size_t nks, j; |
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271 | sym_iter i; |
272 | |
273 | n = d->len; |
274 | DENSURE(d, 4); |
275 | p = d->buf + n; |
276 | STORE16(p, k->e & KF_ENCMASK); |
277 | d->len += 4; |
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278 | |
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279 | for (nks = 0, sym_mkiter(&i, &k->u.s); |
280 | (ks = sym_next(&i)) != 0; |
281 | nks++); |
282 | if (nks) { |
283 | ksv = xmalloc(nks * sizeof(*ksv)); |
284 | for (j = 0, sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; j++) |
285 | ksv[j] = ks; |
286 | qsort(ksv, nks, sizeof(*ksv), ksbyname); |
287 | for (j = 0; j < nks; j++) { |
288 | size_t o = d->len; |
289 | ks = ksv[j]; |
290 | DENSURE(d, 1); |
291 | *(octet *)(d->buf + d->len++) = strlen(SYM_NAME(ks)); |
292 | DPUTS(d, SYM_NAME(ks)); |
293 | while (d->len & 3) |
294 | DPUTC(d, 0); |
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295 | if (key_encode(ks->k, d, kf)) |
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296 | rc = 1; |
297 | else |
298 | d->len = o; |
299 | } |
300 | xfree(ksv); |
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301 | } |
302 | if (!rc) |
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303 | d->len = n; |
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304 | else { |
305 | p = d->buf + n + 2; |
306 | n = d->len - n - 4; |
307 | STORE16(p, n); |
308 | } |
309 | } break; |
310 | } |
311 | while (d->len & 3) |
312 | DPUTC(d, 0); |
313 | return (rc); |
314 | } |
315 | |
316 | /*----- That's all, folks -------------------------------------------------*/ |