052b36d0 |
1 | /* -*-c-*- |
2 | * |
3 | * $Id: key-binary.c,v 1.1 2000/02/12 18:21:02 mdw Exp $ |
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 $ |
33 | * Revision 1.1 2000/02/12 18:21:02 mdw |
34 | * Overhaul of key management (again). |
35 | * |
36 | */ |
37 | |
38 | /*----- Header files ------------------------------------------------------*/ |
39 | |
40 | #include <stdlib.h> |
41 | #include <string.h> |
42 | |
43 | #include <mLib/bits.h> |
44 | #include <mLib/dstr.h> |
45 | #include <mLib/sub.h> |
46 | #include <mLib/sym.h> |
47 | |
48 | #include "key-data.h" |
49 | #include "mp.h" |
50 | #include "mptext.h" |
51 | |
52 | /*----- Main code ---------------------------------------------------------*/ |
53 | |
54 | /* --- @key_decode@ --- * |
55 | * |
56 | * Arguments: @const void *p@ = pointer to buffer to read |
57 | * @size_t sz@ = size of the buffer |
58 | * @key_data *k@ = pointer to key data block to write to |
59 | * |
60 | * Returns: Zero if everything worked, nonzero otherwise. |
61 | * |
62 | * Use: Decodes a binary representation of a key. |
63 | */ |
64 | |
65 | int key_decode(const void *p, size_t sz, key_data *k) |
66 | { |
67 | const octet *q = p; |
68 | size_t psz; |
69 | unsigned e; |
70 | |
71 | /* --- Parse the header information --- * |
72 | * |
73 | * Make sure the size matches external reality. Security holes have been |
74 | * known to creep in without this sort of check. (No, this isn't an after- |
75 | * the-fact patch-up.) |
76 | */ |
77 | |
78 | e = LOAD16(q); |
79 | psz = LOAD16(q + 2); |
80 | if (psz + 4 > sz) |
81 | return (-1); |
82 | k->e = e; |
83 | |
84 | /* --- Now decide what to do --- */ |
85 | |
86 | switch (e & KF_ENCMASK) { |
87 | |
88 | /* --- Plain binary data --- */ |
89 | |
90 | case KENC_BINARY: |
91 | case KENC_ENCRYPT: |
92 | k->u.k.k = sub_alloc(psz); |
93 | memcpy(k->u.k.k, q + 4, psz); |
94 | k->u.k.sz = psz; |
95 | break; |
96 | |
97 | /* --- Multiprecision integer data --- */ |
98 | |
99 | case KENC_MP: |
100 | k->u.m = mp_loadb(MP_NEW, q + 4, psz); |
101 | if (k->e & KF_BURN) |
102 | mp_burn(k->u.m); |
103 | break; |
104 | |
105 | /* --- Structured key data --- */ |
106 | |
107 | case KENC_STRUCT: { |
108 | dstr d = DSTR_INIT; |
109 | key_struct *ks; |
110 | unsigned f; |
111 | |
112 | if ((k->e & ~KF_ENCMASK) || (psz & 3)) |
113 | return (-1); |
114 | q += 4; |
115 | sym_create(&k->u.s); |
116 | |
117 | while (psz) { |
118 | |
119 | /* --- Read the tag string --- */ |
120 | |
121 | DRESET(&d); |
122 | sz = LOAD8(q); |
123 | if (sz >= psz) |
124 | goto fail; |
125 | DPUTM(&d, q + 1, sz); |
126 | DPUTZ(&d); |
127 | sz = (sz + 4) & ~3; |
128 | q += sz; psz -= sz; |
129 | |
130 | /* --- Read the encoding and size --- */ |
131 | |
132 | e = LOAD16(q); |
133 | sz = (LOAD16(q + 2) + 7) & ~3; |
134 | if (sz > psz) |
135 | goto fail; |
136 | |
137 | /* --- Create a table node and fill it in --- */ |
138 | |
139 | ks = sym_find(&k->u.s, d.buf, d.len + 1, sizeof(*ks), &f); |
140 | if (f) |
141 | goto fail; |
142 | if (key_decode(q, sz, &ks->k)) { |
143 | sym_remove(&k->u.s, ks); |
144 | goto fail; |
145 | } |
146 | psz -= sz; |
147 | q += sz; |
148 | } |
149 | dstr_destroy(&d); |
150 | break; |
151 | |
152 | /* --- Tidy up after a failure --- */ |
153 | |
154 | fail: |
155 | dstr_destroy(&d); |
156 | key_destroy(k); |
157 | return (-1); |
158 | } break; |
159 | |
160 | /* --- Everything else --- */ |
161 | |
162 | default: |
163 | return (-1); |
164 | } |
165 | |
166 | /* --- OK, that was good --- */ |
167 | |
168 | return (0); |
169 | } |
170 | |
171 | /* --- @key_encode@ --- * |
172 | * |
173 | * Arguments: @key_data *k@ = pointer to key data block |
174 | * @dstr *d@ = pointer to destination string |
175 | * @const key_filter *kf@ = pointer to key selection block |
176 | * |
177 | * Returns: Nonzero if an item was actually written. |
178 | * |
179 | * Use: Encodes a key block as binary data. |
180 | */ |
181 | |
182 | int key_encode(key_data *k, dstr *d, const key_filter *kf) |
183 | { |
184 | int rc = 0; |
185 | if (!KEY_MATCH(k, kf)) |
186 | return (0); |
187 | switch (k->e & KF_ENCMASK) { |
188 | case KENC_BINARY: |
189 | case KENC_ENCRYPT: { |
190 | char *p; |
191 | |
192 | DENSURE(d, (k->u.k.sz + 7) & ~3); |
193 | p = d->buf + d->len; |
194 | STORE16(p, k->e); |
195 | STORE16(p + 2, k->u.k.sz); |
196 | d->len += 4; |
197 | DPUTM(d, k->u.k.k, k->u.k.sz); |
198 | rc = 1; |
199 | } break; |
200 | |
201 | case KENC_MP: { |
202 | char *p; |
203 | size_t sz = mp_octets(k->u.m); |
204 | |
205 | DENSURE(d, (sz + 7) & ~3); |
206 | p = d->buf + d->len; |
207 | STORE16(p, k->e); |
208 | STORE16(p + 2, sz); |
209 | mp_storeb(k->u.m, p + 4, sz); |
210 | d->len += sz + 4; |
211 | rc = 1; |
212 | } break; |
213 | |
214 | case KENC_STRUCT: { |
215 | size_t n; |
216 | char *p; |
217 | key_struct *ks; |
218 | sym_iter i; |
219 | |
220 | n = d->len; |
221 | DENSURE(d, 4); |
222 | p = d->buf + n; |
223 | STORE16(p, k->e & KF_ENCMASK); |
224 | d->len += 4; |
225 | for (sym_mkiter(&i, &k->u.s); (ks = sym_next(&i)) != 0; ) { |
226 | size_t o = d->len; |
227 | DENSURE(d, 1); |
228 | *(octet *)(d->buf + d->len++) = strlen(SYM_NAME(ks)); |
229 | DPUTS(d, SYM_NAME(ks)); |
230 | while (d->len & 3) |
231 | DPUTC(d, 0); |
232 | if (key_encode(&ks->k, d, kf)) |
233 | rc = 1; |
234 | else |
235 | d->len = o; |
236 | } |
237 | if (!rc) |
238 | d->len = n; |
239 | else { |
240 | p = d->buf + n + 2; |
241 | n = d->len - n - 4; |
242 | STORE16(p, n); |
243 | } |
244 | } break; |
245 | } |
246 | while (d->len & 3) |
247 | DPUTC(d, 0); |
248 | return (rc); |
249 | } |
250 | |
251 | /*----- That's all, folks -------------------------------------------------*/ |