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Commit | Line | Data |
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9b141126 UM |
1 | /* crypto/bn/bn_ctx.c */ |
2 | /* Written by Ulf Moeller for the OpenSSL project. */ | |
3 | /* ==================================================================== | |
5c98b2ca | 4 | * Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved. |
9b141126 UM |
5 | * |
6 | * Redistribution and use in source and binary forms, with or without | |
7 | * modification, are permitted provided that the following conditions | |
8 | * are met: | |
9 | * | |
10 | * 1. Redistributions of source code must retain the above copyright | |
0f113f3e | 11 | * notice, this list of conditions and the following disclaimer. |
9b141126 UM |
12 | * |
13 | * 2. Redistributions in binary form must reproduce the above copyright | |
14 | * notice, this list of conditions and the following disclaimer in | |
15 | * the documentation and/or other materials provided with the | |
16 | * distribution. | |
17 | * | |
18 | * 3. All advertising materials mentioning features or use of this | |
19 | * software must display the following acknowledgment: | |
20 | * "This product includes software developed by the OpenSSL Project | |
21 | * for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | |
22 | * | |
23 | * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | |
24 | * endorse or promote products derived from this software without | |
25 | * prior written permission. For written permission, please contact | |
26 | * openssl-core@openssl.org. | |
27 | * | |
28 | * 5. Products derived from this software may not be called "OpenSSL" | |
29 | * nor may "OpenSSL" appear in their names without prior written | |
30 | * permission of the OpenSSL Project. | |
31 | * | |
32 | * 6. Redistributions of any form whatsoever must retain the following | |
33 | * acknowledgment: | |
34 | * "This product includes software developed by the OpenSSL Project | |
35 | * for use in the OpenSSL Toolkit (http://www.openssl.org/)" | |
36 | * | |
37 | * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | |
38 | * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
39 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | |
40 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | |
41 | * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
42 | * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
43 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
44 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
45 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | |
46 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | |
47 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | |
48 | * OF THE POSSIBILITY OF SUCH DAMAGE. | |
49 | * ==================================================================== | |
50 | * | |
51 | * This product includes cryptographic software written by Eric Young | |
52 | * (eay@cryptsoft.com). This product includes software written by Tim | |
53 | * Hudson (tjh@cryptsoft.com). | |
54 | * | |
55 | */ | |
56 | ||
2ce90b9b | 57 | #if !defined(BN_CTX_DEBUG) && !defined(BN_DEBUG) |
0f113f3e MC |
58 | # ifndef NDEBUG |
59 | # define NDEBUG | |
60 | # endif | |
2ce90b9b | 61 | #endif |
7cc684f4 | 62 | |
9b141126 | 63 | #include <assert.h> |
c62b26fd | 64 | |
b39fc560 | 65 | #include "internal/cryptlib.h" |
c62b26fd | 66 | #include "bn_lcl.h" |
9b141126 | 67 | |
3a83462d MC |
68 | /*- |
69 | * TODO list | |
5c98b2ca GT |
70 | * |
71 | * 1. Check a bunch of "(words+1)" type hacks in various bignum functions and | |
72 | * check they can be safely removed. | |
5c98b2ca | 73 | * - Check +1 and other ugliness in BN_from_montgomery() |
5c98b2ca GT |
74 | * |
75 | * 2. Consider allowing a BN_new_ex() that, at least, lets you specify an | |
76 | * appropriate 'block' size that will be honoured by bn_expand_internal() to | |
77 | * prevent piddly little reallocations. OTOH, profiling bignum expansions in | |
78 | * BN_CTX doesn't show this to be a big issue. | |
79 | */ | |
80 | ||
81 | /* How many bignums are in each "pool item"; */ | |
0f113f3e | 82 | #define BN_CTX_POOL_SIZE 16 |
5c98b2ca | 83 | /* The stack frame info is resizing, set a first-time expansion size; */ |
0f113f3e | 84 | #define BN_CTX_START_FRAMES 32 |
5c98b2ca GT |
85 | |
86 | /***********/ | |
87 | /* BN_POOL */ | |
88 | /***********/ | |
89 | ||
90 | /* A bundle of bignums that can be linked with other bundles */ | |
0f113f3e MC |
91 | typedef struct bignum_pool_item { |
92 | /* The bignum values */ | |
93 | BIGNUM vals[BN_CTX_POOL_SIZE]; | |
94 | /* Linked-list admin */ | |
95 | struct bignum_pool_item *prev, *next; | |
96 | } BN_POOL_ITEM; | |
5c98b2ca | 97 | /* A linked-list of bignums grouped in bundles */ |
0f113f3e MC |
98 | typedef struct bignum_pool { |
99 | /* Linked-list admin */ | |
100 | BN_POOL_ITEM *head, *current, *tail; | |
101 | /* Stack depth and allocation size */ | |
102 | unsigned used, size; | |
103 | } BN_POOL; | |
104 | static void BN_POOL_init(BN_POOL *); | |
105 | static void BN_POOL_finish(BN_POOL *); | |
0f113f3e MC |
106 | static BIGNUM *BN_POOL_get(BN_POOL *); |
107 | static void BN_POOL_release(BN_POOL *, unsigned int); | |
5c98b2ca GT |
108 | |
109 | /************/ | |
110 | /* BN_STACK */ | |
111 | /************/ | |
112 | ||
113 | /* A wrapper to manage the "stack frames" */ | |
0f113f3e MC |
114 | typedef struct bignum_ctx_stack { |
115 | /* Array of indexes into the bignum stack */ | |
116 | unsigned int *indexes; | |
117 | /* Number of stack frames, and the size of the allocated array */ | |
118 | unsigned int depth, size; | |
119 | } BN_STACK; | |
120 | static void BN_STACK_init(BN_STACK *); | |
121 | static void BN_STACK_finish(BN_STACK *); | |
0f113f3e MC |
122 | static int BN_STACK_push(BN_STACK *, unsigned int); |
123 | static unsigned int BN_STACK_pop(BN_STACK *); | |
5c98b2ca GT |
124 | |
125 | /**********/ | |
126 | /* BN_CTX */ | |
127 | /**********/ | |
128 | ||
129 | /* The opaque BN_CTX type */ | |
0f113f3e MC |
130 | struct bignum_ctx { |
131 | /* The bignum bundles */ | |
132 | BN_POOL pool; | |
133 | /* The "stack frames", if you will */ | |
134 | BN_STACK stack; | |
135 | /* The number of bignums currently assigned */ | |
136 | unsigned int used; | |
137 | /* Depth of stack overflow */ | |
138 | int err_stack; | |
139 | /* Block "gets" until an "end" (compatibility behaviour) */ | |
140 | int too_many; | |
141 | }; | |
9b141126 | 142 | |
5c98b2ca GT |
143 | /* Enable this to find BN_CTX bugs */ |
144 | #ifdef BN_CTX_DEBUG | |
145 | static const char *ctxdbg_cur = NULL; | |
146 | static void ctxdbg(BN_CTX *ctx) | |
0f113f3e MC |
147 | { |
148 | unsigned int bnidx = 0, fpidx = 0; | |
149 | BN_POOL_ITEM *item = ctx->pool.head; | |
150 | BN_STACK *stack = &ctx->stack; | |
151 | fprintf(stderr, "(%16p): ", ctx); | |
152 | while (bnidx < ctx->used) { | |
153 | fprintf(stderr, "%03x ", item->vals[bnidx++ % BN_CTX_POOL_SIZE].dmax); | |
154 | if (!(bnidx % BN_CTX_POOL_SIZE)) | |
155 | item = item->next; | |
156 | } | |
157 | fprintf(stderr, "\n"); | |
158 | bnidx = 0; | |
159 | fprintf(stderr, " : "); | |
160 | while (fpidx < stack->depth) { | |
161 | while (bnidx++ < stack->indexes[fpidx]) | |
162 | fprintf(stderr, " "); | |
163 | fprintf(stderr, "^^^ "); | |
164 | bnidx++; | |
165 | fpidx++; | |
166 | } | |
167 | fprintf(stderr, "\n"); | |
168 | } | |
169 | ||
170 | # define CTXDBG_ENTRY(str, ctx) do { \ | |
171 | ctxdbg_cur = (str); \ | |
172 | fprintf(stderr,"Starting %s\n", ctxdbg_cur); \ | |
173 | ctxdbg(ctx); \ | |
174 | } while(0) | |
175 | # define CTXDBG_EXIT(ctx) do { \ | |
176 | fprintf(stderr,"Ending %s\n", ctxdbg_cur); \ | |
177 | ctxdbg(ctx); \ | |
178 | } while(0) | |
179 | # define CTXDBG_RET(ctx,ret) | |
2ce90b9b | 180 | #else |
0f113f3e MC |
181 | # define CTXDBG_ENTRY(str, ctx) |
182 | # define CTXDBG_EXIT(ctx) | |
183 | # define CTXDBG_RET(ctx,ret) | |
2ce90b9b | 184 | #endif |
5c98b2ca | 185 | |
9b141126 | 186 | |
2ce90b9b | 187 | BN_CTX *BN_CTX_new(void) |
0f113f3e | 188 | { |
b4faea50 | 189 | BN_CTX *ret = OPENSSL_malloc(sizeof(*ret)); |
0f113f3e MC |
190 | if (!ret) { |
191 | BNerr(BN_F_BN_CTX_NEW, ERR_R_MALLOC_FAILURE); | |
192 | return NULL; | |
193 | } | |
194 | /* Initialise the structure */ | |
195 | BN_POOL_init(&ret->pool); | |
196 | BN_STACK_init(&ret->stack); | |
197 | ret->used = 0; | |
198 | ret->err_stack = 0; | |
199 | ret->too_many = 0; | |
200 | return ret; | |
201 | } | |
2ce90b9b | 202 | |
9b141126 | 203 | void BN_CTX_free(BN_CTX *ctx) |
0f113f3e MC |
204 | { |
205 | if (ctx == NULL) | |
206 | return; | |
5c98b2ca | 207 | #ifdef BN_CTX_DEBUG |
0f113f3e MC |
208 | { |
209 | BN_POOL_ITEM *pool = ctx->pool.head; | |
210 | fprintf(stderr, "BN_CTX_free, stack-size=%d, pool-bignums=%d\n", | |
211 | ctx->stack.size, ctx->pool.size); | |
212 | fprintf(stderr, "dmaxs: "); | |
213 | while (pool) { | |
214 | unsigned loop = 0; | |
215 | while (loop < BN_CTX_POOL_SIZE) | |
216 | fprintf(stderr, "%02x ", pool->vals[loop++].dmax); | |
217 | pool = pool->next; | |
218 | } | |
219 | fprintf(stderr, "\n"); | |
220 | } | |
5c98b2ca | 221 | #endif |
0f113f3e MC |
222 | BN_STACK_finish(&ctx->stack); |
223 | BN_POOL_finish(&ctx->pool); | |
224 | OPENSSL_free(ctx); | |
225 | } | |
9b141126 UM |
226 | |
227 | void BN_CTX_start(BN_CTX *ctx) | |
0f113f3e MC |
228 | { |
229 | CTXDBG_ENTRY("BN_CTX_start", ctx); | |
230 | /* If we're already overflowing ... */ | |
231 | if (ctx->err_stack || ctx->too_many) | |
232 | ctx->err_stack++; | |
233 | /* (Try to) get a new frame pointer */ | |
234 | else if (!BN_STACK_push(&ctx->stack, ctx->used)) { | |
235 | BNerr(BN_F_BN_CTX_START, BN_R_TOO_MANY_TEMPORARY_VARIABLES); | |
236 | ctx->err_stack++; | |
237 | } | |
238 | CTXDBG_EXIT(ctx); | |
239 | } | |
9b141126 | 240 | |
5c98b2ca | 241 | void BN_CTX_end(BN_CTX *ctx) |
0f113f3e MC |
242 | { |
243 | CTXDBG_ENTRY("BN_CTX_end", ctx); | |
244 | if (ctx->err_stack) | |
245 | ctx->err_stack--; | |
246 | else { | |
247 | unsigned int fp = BN_STACK_pop(&ctx->stack); | |
248 | /* Does this stack frame have anything to release? */ | |
249 | if (fp < ctx->used) | |
250 | BN_POOL_release(&ctx->pool, ctx->used - fp); | |
251 | ctx->used = fp; | |
252 | /* Unjam "too_many" in case "get" had failed */ | |
253 | ctx->too_many = 0; | |
254 | } | |
255 | CTXDBG_EXIT(ctx); | |
256 | } | |
7f7b8d68 | 257 | |
9b141126 | 258 | BIGNUM *BN_CTX_get(BN_CTX *ctx) |
0f113f3e MC |
259 | { |
260 | BIGNUM *ret; | |
261 | CTXDBG_ENTRY("BN_CTX_get", ctx); | |
262 | if (ctx->err_stack || ctx->too_many) | |
263 | return NULL; | |
264 | if ((ret = BN_POOL_get(&ctx->pool)) == NULL) { | |
265 | /* | |
266 | * Setting too_many prevents repeated "get" attempts from cluttering | |
267 | * the error stack. | |
268 | */ | |
269 | ctx->too_many = 1; | |
270 | BNerr(BN_F_BN_CTX_GET, BN_R_TOO_MANY_TEMPORARY_VARIABLES); | |
271 | return NULL; | |
272 | } | |
273 | /* OK, make sure the returned bignum is "zero" */ | |
274 | BN_zero(ret); | |
275 | ctx->used++; | |
276 | CTXDBG_RET(ctx, ret); | |
277 | return ret; | |
278 | } | |
9b141126 | 279 | |
5c98b2ca GT |
280 | /************/ |
281 | /* BN_STACK */ | |
282 | /************/ | |
283 | ||
284 | static void BN_STACK_init(BN_STACK *st) | |
0f113f3e MC |
285 | { |
286 | st->indexes = NULL; | |
287 | st->depth = st->size = 0; | |
288 | } | |
5c98b2ca GT |
289 | |
290 | static void BN_STACK_finish(BN_STACK *st) | |
0f113f3e MC |
291 | { |
292 | if (st->size) | |
293 | OPENSSL_free(st->indexes); | |
294 | } | |
37e48b88 | 295 | |
5c98b2ca GT |
296 | |
297 | static int BN_STACK_push(BN_STACK *st, unsigned int idx) | |
0f113f3e MC |
298 | { |
299 | if (st->depth == st->size) | |
300 | /* Need to expand */ | |
301 | { | |
302 | unsigned int newsize = (st->size ? | |
303 | (st->size * 3 / 2) : BN_CTX_START_FRAMES); | |
304 | unsigned int *newitems = OPENSSL_malloc(newsize * | |
305 | sizeof(unsigned int)); | |
306 | if (!newitems) | |
307 | return 0; | |
308 | if (st->depth) | |
309 | memcpy(newitems, st->indexes, st->depth * sizeof(unsigned int)); | |
310 | if (st->size) | |
311 | OPENSSL_free(st->indexes); | |
312 | st->indexes = newitems; | |
313 | st->size = newsize; | |
314 | } | |
315 | st->indexes[(st->depth)++] = idx; | |
316 | return 1; | |
317 | } | |
5c98b2ca GT |
318 | |
319 | static unsigned int BN_STACK_pop(BN_STACK *st) | |
0f113f3e MC |
320 | { |
321 | return st->indexes[--(st->depth)]; | |
322 | } | |
5c98b2ca GT |
323 | |
324 | /***********/ | |
325 | /* BN_POOL */ | |
326 | /***********/ | |
327 | ||
328 | static void BN_POOL_init(BN_POOL *p) | |
0f113f3e MC |
329 | { |
330 | p->head = p->current = p->tail = NULL; | |
331 | p->used = p->size = 0; | |
332 | } | |
5c98b2ca GT |
333 | |
334 | static void BN_POOL_finish(BN_POOL *p) | |
0f113f3e MC |
335 | { |
336 | while (p->head) { | |
337 | unsigned int loop = 0; | |
338 | BIGNUM *bn = p->head->vals; | |
339 | while (loop++ < BN_CTX_POOL_SIZE) { | |
340 | if (bn->d) | |
341 | BN_clear_free(bn); | |
342 | bn++; | |
343 | } | |
344 | p->current = p->head->next; | |
345 | OPENSSL_free(p->head); | |
346 | p->head = p->current; | |
347 | } | |
348 | } | |
5c98b2ca | 349 | |
5c98b2ca GT |
350 | |
351 | static BIGNUM *BN_POOL_get(BN_POOL *p) | |
0f113f3e MC |
352 | { |
353 | if (p->used == p->size) { | |
354 | BIGNUM *bn; | |
355 | unsigned int loop = 0; | |
b4faea50 | 356 | BN_POOL_ITEM *item = OPENSSL_malloc(sizeof(*item)); |
0f113f3e MC |
357 | if (!item) |
358 | return NULL; | |
359 | /* Initialise the structure */ | |
360 | bn = item->vals; | |
361 | while (loop++ < BN_CTX_POOL_SIZE) | |
362 | BN_init(bn++); | |
363 | item->prev = p->tail; | |
364 | item->next = NULL; | |
365 | /* Link it in */ | |
366 | if (!p->head) | |
367 | p->head = p->current = p->tail = item; | |
368 | else { | |
369 | p->tail->next = item; | |
370 | p->tail = item; | |
371 | p->current = item; | |
372 | } | |
373 | p->size += BN_CTX_POOL_SIZE; | |
374 | p->used++; | |
375 | /* Return the first bignum from the new pool */ | |
376 | return item->vals; | |
377 | } | |
378 | if (!p->used) | |
379 | p->current = p->head; | |
380 | else if ((p->used % BN_CTX_POOL_SIZE) == 0) | |
381 | p->current = p->current->next; | |
382 | return p->current->vals + ((p->used++) % BN_CTX_POOL_SIZE); | |
383 | } | |
5c98b2ca GT |
384 | |
385 | static void BN_POOL_release(BN_POOL *p, unsigned int num) | |
0f113f3e MC |
386 | { |
387 | unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE; | |
388 | p->used -= num; | |
389 | while (num--) { | |
390 | bn_check_top(p->current->vals + offset); | |
391 | if (!offset) { | |
392 | offset = BN_CTX_POOL_SIZE - 1; | |
393 | p->current = p->current->prev; | |
394 | } else | |
395 | offset--; | |
396 | } | |
397 | } |