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