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1 | /* -*-c-*- |
2 | * |
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3 | * Key binary encoding |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
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16 | * |
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17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include <stdlib.h> |
31 | #include <string.h> |
32 | |
33 | #include <mLib/bits.h> |
34 | #include <mLib/dstr.h> |
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35 | #include <mLib/macros.h> |
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36 | #include <mLib/sub.h> |
37 | #include <mLib/sym.h> |
38 | |
39 | #include "key-data.h" |
40 | #include "mp.h" |
41 | #include "mptext.h" |
42 | |
43 | /*----- Main code ---------------------------------------------------------*/ |
44 | |
45 | /* --- @key_decode@ --- * |
46 | * |
47 | * Arguments: @const void *p@ = pointer to buffer to read |
48 | * @size_t sz@ = size of the buffer |
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49 | * |
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50 | * Returns: The newly-read key data, or null if it failed. |
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51 | * |
52 | * Use: Decodes a binary representation of a key. |
53 | */ |
54 | |
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55 | key_data *key_decode(const void *p, size_t sz) |
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56 | { |
57 | const octet *q = p; |
58 | size_t psz; |
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59 | key_data *kd; |
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60 | unsigned e; |
61 | |
62 | /* --- Parse the header information --- * |
63 | * |
64 | * Make sure the size matches external reality. Security holes have been |
65 | * known to creep in without this sort of check. (No, this isn't an after- |
66 | * the-fact patch-up.) |
67 | */ |
68 | |
69 | e = LOAD16(q); |
70 | psz = LOAD16(q + 2); |
71 | if (psz + 4 > sz) |
ef13e9a4 |
72 | return (0); |
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73 | |
74 | /* --- Now decide what to do --- */ |
75 | |
76 | switch (e & KF_ENCMASK) { |
77 | |
78 | /* --- Plain binary data --- */ |
79 | |
80 | case KENC_BINARY: |
81 | case KENC_ENCRYPT: |
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82 | kd = key_newbinary(e, q + 4, psz); |
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83 | break; |
84 | |
85 | /* --- Multiprecision integer data --- */ |
86 | |
87 | case KENC_MP: |
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88 | kd = key_newmp(e, mp_loadb(e & KF_BURN ? MP_NEWSEC : MP_NEW, |
89 | q + 4, psz)); |
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90 | break; |
91 | |
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92 | /* --- String data --- */ |
93 | |
94 | case KENC_STRING: |
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95 | kd = key_newraw(e); |
96 | kd->u.p = xmalloc(sz + 1); |
97 | memcpy(kd->u.p, q + 4, sz); |
98 | kd->u.p[sz] = 0; |
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99 | break; |
100 | |
101 | /* --- Elliptic curve point data --- */ |
102 | |
103 | case KENC_EC: { |
104 | size_t xsz, ysz; |
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105 | kd = key_newraw(e); |
106 | EC_CREATE(&kd->u.e); |
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107 | if (!sz) break; |
ef13e9a4 |
108 | if (sz < 2) return (0); |
1ba83484 |
109 | xsz = LOAD16(q + 4); |
ef13e9a4 |
110 | if (sz < xsz + 4) return (0); |
1ba83484 |
111 | ysz = LOAD16(q + 6 + xsz); |
ef13e9a4 |
112 | if (sz < xsz + ysz + 4) return (0); |
113 | kd->u.e.x = mp_loadb(MP_NEW, q + 6, xsz); |
114 | kd->u.e.y = mp_loadb(MP_NEW, q + 8 + xsz, ysz); |
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115 | } break; |
116 | |
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117 | /* --- Structured key data --- */ |
118 | |
119 | case KENC_STRUCT: { |
120 | dstr d = DSTR_INIT; |
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121 | key_data *nkd; |
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122 | |
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123 | if ((e & ~KF_ENCMASK) || (psz & 3)) |
124 | return (0); |
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125 | q += 4; |
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126 | kd = key_newstruct(); |
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127 | |
128 | while (psz) { |
129 | |
130 | /* --- Read the tag string --- */ |
131 | |
132 | DRESET(&d); |
133 | sz = LOAD8(q); |
134 | if (sz >= psz) |
135 | goto fail; |
136 | DPUTM(&d, q + 1, sz); |
137 | DPUTZ(&d); |
138 | sz = (sz + 4) & ~3; |
139 | q += sz; psz -= sz; |
140 | |
141 | /* --- Read the encoding and size --- */ |
142 | |
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143 | sz = (LOAD16(q + 2) + 7) & ~3; |
144 | if (sz > psz) |
145 | goto fail; |
146 | |
147 | /* --- Create a table node and fill it in --- */ |
148 | |
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149 | if ((nkd = key_decode(q, sz)) == 0) |
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150 | goto fail; |
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151 | key_structsteal(kd, d.buf, nkd); |
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152 | psz -= sz; |
153 | q += sz; |
154 | } |
155 | dstr_destroy(&d); |
156 | break; |
157 | |
158 | /* --- Tidy up after a failure --- */ |
159 | |
160 | fail: |
161 | dstr_destroy(&d); |
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162 | key_drop(kd); |
163 | return (0); |
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164 | } break; |
165 | |
166 | /* --- Everything else --- */ |
167 | |
168 | default: |
ef13e9a4 |
169 | return (0); |
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170 | } |
171 | |
172 | /* --- OK, that was good --- */ |
173 | |
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174 | kd->e = e; |
175 | return (kd); |
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176 | } |
177 | |
178 | /* --- @key_encode@ --- * |
179 | * |
180 | * Arguments: @key_data *k@ = pointer to key data block |
181 | * @dstr *d@ = pointer to destination string |
182 | * @const key_filter *kf@ = pointer to key selection block |
183 | * |
184 | * Returns: Nonzero if an item was actually written. |
185 | * |
186 | * Use: Encodes a key block as binary data. |
187 | */ |
188 | |
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189 | static int ksbyname(const void *a, const void *b) { |
190 | key_struct *const *x = a, *const *y = b; |
191 | return (strcmp(SYM_NAME(*x), SYM_NAME(*y))); |
192 | } |
193 | |
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194 | int key_encode(key_data *k, dstr *d, const key_filter *kf) |
195 | { |
196 | int rc = 0; |
197 | if (!KEY_MATCH(k, kf)) |
198 | return (0); |
199 | switch (k->e & KF_ENCMASK) { |
200 | case KENC_BINARY: |
201 | case KENC_ENCRYPT: { |
202 | char *p; |
203 | |
204 | DENSURE(d, (k->u.k.sz + 7) & ~3); |
205 | p = d->buf + d->len; |
206 | STORE16(p, k->e); |
207 | STORE16(p + 2, k->u.k.sz); |
208 | d->len += 4; |
209 | DPUTM(d, k->u.k.k, k->u.k.sz); |
210 | rc = 1; |
211 | } break; |
212 | |
213 | case KENC_MP: { |
214 | char *p; |
215 | size_t sz = mp_octets(k->u.m); |
216 | |
217 | DENSURE(d, (sz + 7) & ~3); |
218 | p = d->buf + d->len; |
219 | STORE16(p, k->e); |
220 | STORE16(p + 2, sz); |
221 | mp_storeb(k->u.m, p + 4, sz); |
222 | d->len += sz + 4; |
223 | rc = 1; |
224 | } break; |
225 | |
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226 | case KENC_STRING: { |
227 | char *p; |
228 | size_t sz = strlen(k->u.p); |
229 | |
230 | DENSURE(d, (sz + 7) & ~3); |
231 | p = d->buf + d->len; |
232 | STORE16(p, k->e); |
233 | STORE16(p + 2, sz); |
234 | memcpy(p + 4, k->u.p, sz); |
235 | d->len += sz + 4; |
236 | rc = 1; |
237 | } break; |
238 | |
239 | case KENC_EC: { |
240 | char *p; |
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241 | size_t xsz = 0, ysz = 0; |
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242 | size_t sz; |
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243 | |
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244 | if (EC_ATINF(&k->u.e)) |
245 | sz = 0; |
246 | else { |
247 | xsz = mp_octets(k->u.e.x); |
248 | ysz = mp_octets(k->u.e.y); |
249 | sz = xsz + ysz + 4; |
250 | } |
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251 | DENSURE(d, (sz + 7) & ~3); |
252 | p = d->buf + d->len; |
253 | STORE16(p, k->e); |
254 | STORE16(p + 2, sz); |
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255 | if (!EC_ATINF(&k->u.e)) { |
256 | STORE16(p + 4, xsz); |
257 | mp_storeb(k->u.e.x, p + 6, xsz); |
258 | STORE16(p + 6 + xsz, ysz); |
259 | mp_storeb(k->u.e.y, p + 8 + xsz, ysz); |
260 | } |
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261 | d->len += sz + 4; |
262 | rc = 1; |
263 | } break; |
264 | |
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265 | case KENC_STRUCT: { |
266 | size_t n; |
267 | char *p; |
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268 | key_struct *ks, **ksv; |
269 | size_t nks, j; |
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270 | sym_iter i; |
271 | |
272 | n = d->len; |
273 | DENSURE(d, 4); |
274 | p = d->buf + n; |
275 | STORE16(p, k->e & KF_ENCMASK); |
276 | d->len += 4; |
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277 | |
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278 | for (nks = 0, sym_mkiter(&i, &k->u.s); |
279 | (ks = sym_next(&i)) != 0; |
280 | nks++); |
281 | if (nks) { |
282 | ksv = xmalloc(nks * sizeof(*ksv)); |
283 | for (j = 0, sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; j++) |
284 | ksv[j] = ks; |
285 | qsort(ksv, nks, sizeof(*ksv), ksbyname); |
286 | for (j = 0; j < nks; j++) { |
287 | size_t o = d->len; |
288 | ks = ksv[j]; |
289 | DENSURE(d, 1); |
290 | *(octet *)(d->buf + d->len++) = strlen(SYM_NAME(ks)); |
291 | DPUTS(d, SYM_NAME(ks)); |
292 | while (d->len & 3) |
293 | DPUTC(d, 0); |
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294 | if (key_encode(ks->k, d, kf)) |
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295 | rc = 1; |
296 | else |
297 | d->len = o; |
298 | } |
299 | xfree(ksv); |
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300 | } |
301 | if (!rc) |
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302 | d->len = n; |
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303 | else { |
304 | p = d->buf + n + 2; |
305 | n = d->len - n - 4; |
306 | STORE16(p, n); |
307 | } |
308 | } break; |
309 | } |
310 | while (d->len & 3) |
311 | DPUTC(d, 0); |
312 | return (rc); |
313 | } |
314 | |
315 | /*----- That's all, folks -------------------------------------------------*/ |