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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: sslprf.c,v 1.2 2004/04/08 01:36:15 mdw Exp $ |
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4 | * |
5 | * The SSL pseudo-random function |
6 | * |
7 | * (c) 2001 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 <mLib/alloc.h> |
33 | #include <mLib/dstr.h> |
34 | #include <mLib/sub.h> |
35 | |
36 | #include "arena.h" |
37 | #include "ghash.h" |
38 | #include "grand.h" |
39 | #include "paranoia.h" |
40 | #include "sslprf.h" |
41 | |
42 | /*----- Main code ---------------------------------------------------------*/ |
43 | |
44 | /* --- @step@ --- * |
45 | * |
46 | * Arguments: @sslprf_ctx *c@ = pointer to context structure |
47 | * |
48 | * Returns: --- |
49 | * |
50 | * Use: Steps the generator. |
51 | */ |
52 | |
53 | static void step(sslprf_ctx *c) |
54 | { |
55 | octet buf[64]; |
56 | size_t n, sz; |
57 | octet x; |
58 | ghash *h, *hh; |
59 | octet *p; |
60 | |
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61 | h = GH_INIT(c->ci); |
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62 | x = 'A' + c->i - 1; |
63 | for (sz = c->i++; sz > 0; sz -= n) { |
64 | n = sz; |
65 | if (n > sizeof(buf)) |
66 | n = sizeof(buf); |
67 | memset(buf, x, n); |
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68 | GH_HASH(h, buf, n); |
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69 | } |
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70 | GH_HASH(h, c->k, c->ksz); |
71 | GH_HASH(h, c->sd, c->sdsz); |
72 | p = GH_DONE(h, 0); |
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73 | |
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74 | hh = GH_INIT(c->co); |
75 | GH_HASH(hh, c->k, c->ksz); |
76 | GH_HASH(hh, p, c->ihashsz); |
77 | c->p = GH_DONE(hh, 0); |
78 | GH_DESTROY(h); |
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79 | |
80 | c->h = hh; |
81 | c->sz = c->ohashsz; |
82 | } |
83 | |
84 | /* --- @sslprf_init@ --- * |
85 | * |
86 | * Arguments: @sslprf_ctx *c@ = pointer to a context structure |
87 | * @const gchash *hco, *hci@ = outer and inner hash functions |
88 | * @const void *k@ = pointer to secret buffer |
89 | * @size_t ksz@ = size of the secret |
90 | * @const void *sd@ = pointer to seed buffer |
91 | * @size_t sdsz@ = size of the seed |
92 | * |
93 | * Returns: --- |
94 | * |
95 | * Use: Initializes an SSL generator context. |
96 | */ |
97 | |
98 | void sslprf_init(sslprf_ctx *c, const gchash *hco, const gchash *hci, |
99 | const void *k, size_t ksz, |
100 | const void *sd, size_t sdsz) |
101 | { |
102 | c->co = hco; c->ci = hci; |
103 | c->ohashsz = hco->hashsz; c->ihashsz = hci->hashsz; |
104 | c->k = k; c->ksz = ksz; c->sd = sd; c->sdsz = sdsz; |
105 | c->i = 1; |
106 | step(c); |
107 | } |
108 | |
109 | /* --- @sslprf_encrypt@ --- * |
110 | * |
111 | * Arguments: @sslprf_ctx *c@ = pointer to a context structure |
112 | * @const void *src@ = pointer to source buffer |
113 | * @void *dest@ = pointer to destination buffer |
114 | * @size_t sz@ = size of the buffers |
115 | * |
116 | * Returns: --- |
117 | * |
118 | * Use: Encrypts data using the SSL pseudo-random function. If the |
119 | * destination pointer is null, the generator is spun and no |
120 | * output is produced; if the source pointer is null, raw output |
121 | * from the generator is written; otherwise, the source data is |
122 | * XORed with the generator output. |
123 | */ |
124 | |
125 | void sslprf_encrypt(sslprf_ctx *c, const void *src, void *dest, size_t sz) |
126 | { |
127 | const octet *s = src; |
128 | octet *d = dest; |
129 | size_t i, n; |
130 | |
131 | while (sz) { |
132 | if (!c->sz) { |
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133 | GH_DESTROY(c->h); |
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134 | step(c); |
135 | } |
136 | n = c->sz; |
137 | if (n > sz) |
138 | n = sz; |
139 | if (d) { |
140 | if (!s) |
141 | memcpy(d, c->p, n); |
142 | else { |
143 | for (i = 0; i < n; i++) d[i] = s[i] ^ c->p[i]; |
144 | s += n; |
145 | } |
146 | d += n; |
147 | } |
148 | c->p += n; |
149 | c->sz -= n; |
150 | sz -= n; |
151 | } |
152 | } |
153 | |
154 | /* --- @sslprf_free@ --- * |
155 | * |
156 | * Arguments: @sslprf_ctx@ = pointer to a context |
157 | * |
158 | * Returns: --- |
159 | * |
160 | * Use: Frees resources held in an SSL generator context. |
161 | */ |
162 | |
163 | void sslprf_free(sslprf_ctx *c) |
164 | { |
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165 | GH_DESTROY(c->h); |
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166 | } |
167 | |
168 | /* --- Generic random number generator --- */ |
169 | |
170 | typedef struct grctx { |
171 | grand r; |
172 | grand_ops ops; |
173 | sslprf_ctx prf; |
174 | } grctx; |
175 | |
176 | static void grdestroy(grand *r) |
177 | { |
178 | grctx *g = (grctx *)r; |
179 | xfree((char *)g->ops.name); |
180 | xfree((octet *)g->prf.sd); |
181 | sslprf_free(&g->prf); |
182 | BURN(*g); |
183 | S_DESTROY(g); |
184 | } |
185 | |
186 | static void seed(grctx *g, const void *p, size_t sz) |
187 | { |
188 | octet *q; |
189 | xfree((octet *)g->prf.sd); |
190 | g->prf.sd = q = xmalloc(sz); |
191 | memcpy(q, p, sz); |
192 | g->prf.sdsz = sz; |
193 | } |
194 | |
195 | static int grmisc(grand *r, unsigned op, ...) |
196 | { |
197 | grctx *g = (grctx *)r; |
198 | va_list ap; |
199 | int rc = 0; |
200 | uint32 i; |
201 | octet buf[4]; |
202 | va_start(ap, op); |
203 | |
204 | switch (op) { |
205 | case GRAND_CHECK: |
206 | switch (va_arg(ap, unsigned)) { |
207 | case GRAND_CHECK: |
208 | case GRAND_SEEDINT: |
209 | case GRAND_SEEDUINT32: |
210 | case GRAND_SEEDBLOCK: |
211 | case GRAND_SEEDRAND: |
212 | rc = 1; |
213 | break; |
214 | default: |
215 | rc = 0; |
216 | break; |
217 | } |
218 | break; |
219 | case GRAND_SEEDINT: |
220 | i = va_arg(ap, unsigned); |
221 | STORE32(buf, i); |
222 | seed(g, buf, sizeof(buf)); |
223 | break; |
224 | case GRAND_SEEDUINT32: |
225 | i = va_arg(ap, uint32); |
226 | STORE32(buf, i); |
227 | seed(g, buf, sizeof(buf)); |
228 | break; |
229 | case GRAND_SEEDBLOCK: { |
230 | const void *p = va_arg(ap, const void *); |
231 | size_t sz = va_arg(ap, size_t); |
232 | seed(g, p, sz); |
233 | } break; |
234 | case GRAND_SEEDRAND: { |
235 | grand *rr = va_arg(ap, grand *); |
236 | octet buf[16]; |
237 | rr->ops->fill(rr, buf, sizeof(buf)); |
238 | seed(g, buf, sizeof(buf)); |
239 | } break; |
240 | default: |
241 | GRAND_BADOP; |
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242 | break; |
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243 | } |
244 | |
245 | va_end(ap); |
246 | return (rc); |
247 | } |
248 | |
249 | static octet grbyte(grand *r) |
250 | { |
251 | grctx *g = (grctx *)r; |
252 | octet o; |
253 | sslprf_encrypt(&g->prf, 0, &o, 1); |
254 | return (o); |
255 | } |
256 | |
257 | static uint32 grword(grand *r) |
258 | { |
259 | grctx *g = (grctx *)r; |
260 | octet b[4]; |
261 | sslprf_encrypt(&g->prf, 0, &b, sizeof(b)); |
262 | return (LOAD32(b)); |
263 | } |
264 | |
265 | static void grfill(grand *r, void *p, size_t sz) |
266 | { |
267 | grctx *g = (grctx *)r; |
268 | sslprf_encrypt(&g->prf, 0, p, sz); |
269 | } |
270 | |
271 | static const grand_ops grops = { |
272 | "<sslprf-dummy>", |
273 | GRAND_CRYPTO, 0, |
274 | grmisc, grdestroy, |
275 | grword, grbyte, grword, grand_range, grfill |
276 | }; |
277 | |
278 | /* ---@sslprf_rand@ --- * |
279 | * |
280 | * Arguments: @const gchash *hco, const gchash *hci@ = hash functions |
281 | * @const void *k@ = pointer to the key material |
282 | * @size_t ksz@ = size of the key material |
283 | * @const void *sd@ = pointer to the seed material |
284 | * @size_t sdsz@ = size of the seed material |
285 | * |
286 | * Returns: Pointer to generic random number generator interface. |
287 | * |
288 | * Use: Creates a generic generator which does TLS data expansion. |
289 | */ |
290 | |
291 | grand *sslprf_rand(const gchash *hco, const gchash *hci, |
292 | const void *k, size_t ksz, |
293 | const void *sd, size_t sdsz) |
294 | { |
295 | grctx *g = S_CREATE(grctx); |
296 | dstr d = DSTR_INIT; |
297 | octet *q = xmalloc(sdsz); |
298 | memcpy(q, sd, sdsz); |
299 | dstr_putf(&d, "sslprf(%s,%s)", hco->name, hci->name); |
300 | g->ops = grops; |
301 | g->ops.name = xstrdup(d.buf); |
302 | g->r.ops = &g->ops; |
303 | dstr_destroy(&d); |
304 | sslprf_init(&g->prf, hco, hci, k, ksz, q, sdsz); |
305 | return (&g->r); |
306 | } |
307 | |
308 | /*----- Test rig ----------------------------------------------------------*/ |
309 | |
310 | #ifdef TEST_RIG |
311 | |
312 | #include <stdio.h> |
313 | #include <string.h> |
314 | |
315 | #include <mLib/quis.h> |
316 | #include <mLib/testrig.h> |
317 | |
318 | #include "sha.h" |
319 | #include "md5.h" |
320 | |
321 | static int v_generate(dstr *v) |
322 | { |
323 | grand *g; |
324 | dstr d = DSTR_INIT; |
325 | int ok = 1; |
326 | |
327 | g = sslprf_rand(&md5, &sha, v[0].buf, v[0].len, v[1].buf, v[1].len); |
328 | dstr_ensure(&d, v[2].len); |
329 | d.len = v[2].len; |
330 | g->ops->fill(g, d.buf, d.len); |
331 | g->ops->destroy(g); |
332 | if (memcmp(v[2].buf, d.buf, d.len) != 0) { |
333 | ok = 0; |
334 | printf("\nfail sslprf:" |
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335 | "\n\tkey = "); |
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336 | type_hex.dump(&v[0], stdout); |
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337 | printf("\n\tseed = "); type_hex.dump(&v[1], stdout); |
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338 | printf("\n\texpected = "); type_hex.dump(&v[2], stdout); |
339 | printf("\n\tcalculated = "); type_hex.dump(&d, stdout); |
340 | putchar('\n'); |
341 | } |
342 | return (ok); |
343 | } |
344 | |
345 | static test_chunk defs[] = { |
346 | { "sslprf", v_generate, { &type_hex, &type_hex, &type_hex, 0 } }, |
347 | { 0, 0, { 0 } } |
348 | }; |
349 | |
350 | int main(int argc, char *argv[]) |
351 | { |
352 | test_run(argc, argv, defs, SRCDIR"/tests/sslprf"); |
353 | return (0); |
354 | } |
355 | |
356 | #endif |
357 | |
358 | /*----- That's all, folks -------------------------------------------------*/ |