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1 | /* -*-c-*- |
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2 | * |
3 | * The SSL pseudo-random function |
4 | * |
5 | * (c) 2001 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 <mLib/alloc.h> |
31 | #include <mLib/dstr.h> |
32 | #include <mLib/sub.h> |
33 | |
34 | #include "arena.h" |
35 | #include "ghash.h" |
36 | #include "grand.h" |
37 | #include "paranoia.h" |
38 | #include "sslprf.h" |
39 | |
40 | /*----- Main code ---------------------------------------------------------*/ |
41 | |
42 | /* --- @step@ --- * |
43 | * |
44 | * Arguments: @sslprf_ctx *c@ = pointer to context structure |
45 | * |
46 | * Returns: --- |
47 | * |
48 | * Use: Steps the generator. |
49 | */ |
50 | |
51 | static void step(sslprf_ctx *c) |
52 | { |
53 | octet buf[64]; |
54 | size_t n, sz; |
55 | octet x; |
56 | ghash *h, *hh; |
57 | octet *p; |
58 | |
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59 | h = GH_INIT(c->ci); |
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60 | x = 'A' + c->i - 1; |
61 | for (sz = c->i++; sz > 0; sz -= n) { |
62 | n = sz; |
63 | if (n > sizeof(buf)) |
64 | n = sizeof(buf); |
65 | memset(buf, x, n); |
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66 | GH_HASH(h, buf, n); |
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67 | } |
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68 | GH_HASH(h, c->k, c->ksz); |
69 | GH_HASH(h, c->sd, c->sdsz); |
70 | p = GH_DONE(h, 0); |
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71 | |
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72 | hh = GH_INIT(c->co); |
73 | GH_HASH(hh, c->k, c->ksz); |
74 | GH_HASH(hh, p, c->ihashsz); |
75 | c->p = GH_DONE(hh, 0); |
76 | GH_DESTROY(h); |
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77 | |
78 | c->h = hh; |
79 | c->sz = c->ohashsz; |
80 | } |
81 | |
82 | /* --- @sslprf_init@ --- * |
83 | * |
84 | * Arguments: @sslprf_ctx *c@ = pointer to a context structure |
85 | * @const gchash *hco, *hci@ = outer and inner hash functions |
86 | * @const void *k@ = pointer to secret buffer |
87 | * @size_t ksz@ = size of the secret |
88 | * @const void *sd@ = pointer to seed buffer |
89 | * @size_t sdsz@ = size of the seed |
90 | * |
91 | * Returns: --- |
92 | * |
93 | * Use: Initializes an SSL generator context. |
94 | */ |
95 | |
96 | void sslprf_init(sslprf_ctx *c, const gchash *hco, const gchash *hci, |
97 | const void *k, size_t ksz, |
98 | const void *sd, size_t sdsz) |
99 | { |
100 | c->co = hco; c->ci = hci; |
101 | c->ohashsz = hco->hashsz; c->ihashsz = hci->hashsz; |
102 | c->k = k; c->ksz = ksz; c->sd = sd; c->sdsz = sdsz; |
103 | c->i = 1; |
104 | step(c); |
105 | } |
106 | |
107 | /* --- @sslprf_encrypt@ --- * |
108 | * |
109 | * Arguments: @sslprf_ctx *c@ = pointer to a context structure |
110 | * @const void *src@ = pointer to source buffer |
111 | * @void *dest@ = pointer to destination buffer |
112 | * @size_t sz@ = size of the buffers |
113 | * |
114 | * Returns: --- |
115 | * |
116 | * Use: Encrypts data using the SSL pseudo-random function. If the |
117 | * destination pointer is null, the generator is spun and no |
118 | * output is produced; if the source pointer is null, raw output |
119 | * from the generator is written; otherwise, the source data is |
120 | * XORed with the generator output. |
121 | */ |
122 | |
123 | void sslprf_encrypt(sslprf_ctx *c, const void *src, void *dest, size_t sz) |
124 | { |
125 | const octet *s = src; |
126 | octet *d = dest; |
127 | size_t i, n; |
128 | |
129 | while (sz) { |
130 | if (!c->sz) { |
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131 | GH_DESTROY(c->h); |
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132 | step(c); |
133 | } |
134 | n = c->sz; |
135 | if (n > sz) |
136 | n = sz; |
137 | if (d) { |
138 | if (!s) |
139 | memcpy(d, c->p, n); |
140 | else { |
141 | for (i = 0; i < n; i++) d[i] = s[i] ^ c->p[i]; |
142 | s += n; |
143 | } |
144 | d += n; |
145 | } |
146 | c->p += n; |
147 | c->sz -= n; |
148 | sz -= n; |
149 | } |
150 | } |
151 | |
152 | /* --- @sslprf_free@ --- * |
153 | * |
154 | * Arguments: @sslprf_ctx@ = pointer to a context |
155 | * |
156 | * Returns: --- |
157 | * |
158 | * Use: Frees resources held in an SSL generator context. |
159 | */ |
160 | |
161 | void sslprf_free(sslprf_ctx *c) |
162 | { |
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163 | GH_DESTROY(c->h); |
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164 | } |
165 | |
166 | /* --- Generic random number generator --- */ |
167 | |
168 | typedef struct grctx { |
169 | grand r; |
170 | grand_ops ops; |
171 | sslprf_ctx prf; |
172 | } grctx; |
173 | |
174 | static void grdestroy(grand *r) |
175 | { |
176 | grctx *g = (grctx *)r; |
177 | xfree((char *)g->ops.name); |
178 | xfree((octet *)g->prf.sd); |
179 | sslprf_free(&g->prf); |
180 | BURN(*g); |
181 | S_DESTROY(g); |
182 | } |
183 | |
184 | static void seed(grctx *g, const void *p, size_t sz) |
185 | { |
186 | octet *q; |
187 | xfree((octet *)g->prf.sd); |
188 | g->prf.sd = q = xmalloc(sz); |
189 | memcpy(q, p, sz); |
190 | g->prf.sdsz = sz; |
191 | } |
192 | |
193 | static int grmisc(grand *r, unsigned op, ...) |
194 | { |
195 | grctx *g = (grctx *)r; |
196 | va_list ap; |
197 | int rc = 0; |
198 | uint32 i; |
199 | octet buf[4]; |
200 | va_start(ap, op); |
201 | |
202 | switch (op) { |
203 | case GRAND_CHECK: |
204 | switch (va_arg(ap, unsigned)) { |
205 | case GRAND_CHECK: |
206 | case GRAND_SEEDINT: |
207 | case GRAND_SEEDUINT32: |
208 | case GRAND_SEEDBLOCK: |
209 | case GRAND_SEEDRAND: |
210 | rc = 1; |
211 | break; |
212 | default: |
213 | rc = 0; |
214 | break; |
215 | } |
216 | break; |
217 | case GRAND_SEEDINT: |
218 | i = va_arg(ap, unsigned); |
219 | STORE32(buf, i); |
220 | seed(g, buf, sizeof(buf)); |
221 | break; |
222 | case GRAND_SEEDUINT32: |
223 | i = va_arg(ap, uint32); |
224 | STORE32(buf, i); |
225 | seed(g, buf, sizeof(buf)); |
226 | break; |
227 | case GRAND_SEEDBLOCK: { |
228 | const void *p = va_arg(ap, const void *); |
229 | size_t sz = va_arg(ap, size_t); |
230 | seed(g, p, sz); |
231 | } break; |
232 | case GRAND_SEEDRAND: { |
233 | grand *rr = va_arg(ap, grand *); |
234 | octet buf[16]; |
235 | rr->ops->fill(rr, buf, sizeof(buf)); |
236 | seed(g, buf, sizeof(buf)); |
237 | } break; |
238 | default: |
239 | GRAND_BADOP; |
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240 | break; |
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241 | } |
242 | |
243 | va_end(ap); |
244 | return (rc); |
245 | } |
246 | |
247 | static octet grbyte(grand *r) |
248 | { |
249 | grctx *g = (grctx *)r; |
250 | octet o; |
251 | sslprf_encrypt(&g->prf, 0, &o, 1); |
252 | return (o); |
253 | } |
254 | |
255 | static uint32 grword(grand *r) |
256 | { |
257 | grctx *g = (grctx *)r; |
258 | octet b[4]; |
259 | sslprf_encrypt(&g->prf, 0, &b, sizeof(b)); |
260 | return (LOAD32(b)); |
261 | } |
262 | |
263 | static void grfill(grand *r, void *p, size_t sz) |
264 | { |
265 | grctx *g = (grctx *)r; |
266 | sslprf_encrypt(&g->prf, 0, p, sz); |
267 | } |
268 | |
269 | static const grand_ops grops = { |
270 | "<sslprf-dummy>", |
271 | GRAND_CRYPTO, 0, |
272 | grmisc, grdestroy, |
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273 | grword, grbyte, grword, grand_defaultrange, grfill |
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274 | }; |
275 | |
276 | /* ---@sslprf_rand@ --- * |
277 | * |
278 | * Arguments: @const gchash *hco, const gchash *hci@ = hash functions |
279 | * @const void *k@ = pointer to the key material |
280 | * @size_t ksz@ = size of the key material |
281 | * @const void *sd@ = pointer to the seed material |
282 | * @size_t sdsz@ = size of the seed material |
283 | * |
284 | * Returns: Pointer to generic random number generator interface. |
285 | * |
286 | * Use: Creates a generic generator which does TLS data expansion. |
287 | */ |
288 | |
289 | grand *sslprf_rand(const gchash *hco, const gchash *hci, |
290 | const void *k, size_t ksz, |
291 | const void *sd, size_t sdsz) |
292 | { |
293 | grctx *g = S_CREATE(grctx); |
294 | dstr d = DSTR_INIT; |
295 | octet *q = xmalloc(sdsz); |
296 | memcpy(q, sd, sdsz); |
297 | dstr_putf(&d, "sslprf(%s,%s)", hco->name, hci->name); |
298 | g->ops = grops; |
299 | g->ops.name = xstrdup(d.buf); |
300 | g->r.ops = &g->ops; |
301 | dstr_destroy(&d); |
302 | sslprf_init(&g->prf, hco, hci, k, ksz, q, sdsz); |
303 | return (&g->r); |
304 | } |
305 | |
306 | /*----- Test rig ----------------------------------------------------------*/ |
307 | |
308 | #ifdef TEST_RIG |
309 | |
310 | #include <stdio.h> |
311 | #include <string.h> |
312 | |
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313 | #include <mLib/macros.h> |
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314 | #include <mLib/quis.h> |
315 | #include <mLib/testrig.h> |
316 | |
317 | #include "sha.h" |
318 | #include "md5.h" |
319 | |
320 | static int v_generate(dstr *v) |
321 | { |
322 | grand *g; |
323 | dstr d = DSTR_INIT; |
324 | int ok = 1; |
325 | |
326 | g = sslprf_rand(&md5, &sha, v[0].buf, v[0].len, v[1].buf, v[1].len); |
327 | dstr_ensure(&d, v[2].len); |
328 | d.len = v[2].len; |
329 | g->ops->fill(g, d.buf, d.len); |
330 | g->ops->destroy(g); |
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331 | if (MEMCMP(v[2].buf, !=, d.buf, d.len)) { |
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332 | ok = 0; |
333 | printf("\nfail sslprf:" |
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334 | "\n\tkey = "); |
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335 | type_hex.dump(&v[0], stdout); |
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336 | printf("\n\tseed = "); type_hex.dump(&v[1], stdout); |
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337 | printf("\n\texpected = "); type_hex.dump(&v[2], stdout); |
338 | printf("\n\tcalculated = "); type_hex.dump(&d, stdout); |
339 | putchar('\n'); |
340 | } |
341 | return (ok); |
342 | } |
343 | |
344 | static test_chunk defs[] = { |
345 | { "sslprf", v_generate, { &type_hex, &type_hex, &type_hex, 0 } }, |
346 | { 0, 0, { 0 } } |
347 | }; |
348 | |
349 | int main(int argc, char *argv[]) |
350 | { |
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351 | test_run(argc, argv, defs, SRCDIR"/t/sslprf"); |
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352 | return (0); |
353 | } |
354 | |
355 | #endif |
356 | |
357 | /*----- That's all, folks -------------------------------------------------*/ |