1 /* Written by Ulf Moeller for the OpenSSL project. */
2 /* ====================================================================
3 * Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in
14 * the documentation and/or other materials provided with the
17 * 3. All advertising materials mentioning features or use of this
18 * software must display the following acknowledgment:
19 * "This product includes software developed by the OpenSSL Project
20 * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
22 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
23 * endorse or promote products derived from this software without
24 * prior written permission. For written permission, please contact
25 * openssl-core@openssl.org.
27 * 5. Products derived from this software may not be called "OpenSSL"
28 * nor may "OpenSSL" appear in their names without prior written
29 * permission of the OpenSSL Project.
31 * 6. Redistributions of any form whatsoever must retain the following
33 * "This product includes software developed by the OpenSSL Project
34 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
36 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
37 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
38 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
39 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
40 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
41 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
42 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
43 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
44 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
45 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
46 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
47 * OF THE POSSIBILITY OF SUCH DAMAGE.
48 * ====================================================================
50 * This product includes cryptographic software written by Eric Young
51 * (eay@cryptsoft.com). This product includes software written by Tim
52 * Hudson (tjh@cryptsoft.com).
56 #include "internal/cryptlib.h"
62 * 1. Check a bunch of "(words+1)" type hacks in various bignum functions and
63 * check they can be safely removed.
64 * - Check +1 and other ugliness in BN_from_montgomery()
66 * 2. Consider allowing a BN_new_ex() that, at least, lets you specify an
67 * appropriate 'block' size that will be honoured by bn_expand_internal() to
68 * prevent piddly little reallocations. OTOH, profiling bignum expansions in
69 * BN_CTX doesn't show this to be a big issue.
72 /* How many bignums are in each "pool item"; */
73 #define BN_CTX_POOL_SIZE 16
74 /* The stack frame info is resizing, set a first-time expansion size; */
75 #define BN_CTX_START_FRAMES 32
81 /* A bundle of bignums that can be linked with other bundles */
82 typedef struct bignum_pool_item {
83 /* The bignum values */
84 BIGNUM vals[BN_CTX_POOL_SIZE];
85 /* Linked-list admin */
86 struct bignum_pool_item *prev, *next;
88 /* A linked-list of bignums grouped in bundles */
89 typedef struct bignum_pool {
90 /* Linked-list admin */
91 BN_POOL_ITEM *head, *current, *tail;
92 /* Stack depth and allocation size */
95 static void BN_POOL_init(BN_POOL *);
96 static void BN_POOL_finish(BN_POOL *);
97 static BIGNUM *BN_POOL_get(BN_POOL *, int);
98 static void BN_POOL_release(BN_POOL *, unsigned int);
104 /* A wrapper to manage the "stack frames" */
105 typedef struct bignum_ctx_stack {
106 /* Array of indexes into the bignum stack */
107 unsigned int *indexes;
108 /* Number of stack frames, and the size of the allocated array */
109 unsigned int depth, size;
111 static void BN_STACK_init(BN_STACK *);
112 static void BN_STACK_finish(BN_STACK *);
113 static int BN_STACK_push(BN_STACK *, unsigned int);
114 static unsigned int BN_STACK_pop(BN_STACK *);
120 /* The opaque BN_CTX type */
122 /* The bignum bundles */
124 /* The "stack frames", if you will */
126 /* The number of bignums currently assigned */
128 /* Depth of stack overflow */
130 /* Block "gets" until an "end" (compatibility behaviour) */
136 /* Enable this to find BN_CTX bugs */
138 static const char *ctxdbg_cur = NULL;
139 static void ctxdbg(BN_CTX *ctx)
141 unsigned int bnidx = 0, fpidx = 0;
142 BN_POOL_ITEM *item = ctx->pool.head;
143 BN_STACK *stack = &ctx->stack;
144 fprintf(stderr, "(%16p): ", ctx);
145 while (bnidx < ctx->used) {
146 fprintf(stderr, "%03x ", item->vals[bnidx++ % BN_CTX_POOL_SIZE].dmax);
147 if (!(bnidx % BN_CTX_POOL_SIZE))
150 fprintf(stderr, "\n");
152 fprintf(stderr, " : ");
153 while (fpidx < stack->depth) {
154 while (bnidx++ < stack->indexes[fpidx])
155 fprintf(stderr, " ");
156 fprintf(stderr, "^^^ ");
160 fprintf(stderr, "\n");
163 # define CTXDBG_ENTRY(str, ctx) do { \
164 ctxdbg_cur = (str); \
165 fprintf(stderr,"Starting %s\n", ctxdbg_cur); \
168 # define CTXDBG_EXIT(ctx) do { \
169 fprintf(stderr,"Ending %s\n", ctxdbg_cur); \
172 # define CTXDBG_RET(ctx,ret)
174 # define CTXDBG_ENTRY(str, ctx)
175 # define CTXDBG_EXIT(ctx)
176 # define CTXDBG_RET(ctx,ret)
180 BN_CTX *BN_CTX_new(void)
184 if ((ret = OPENSSL_zalloc(sizeof(*ret))) == NULL) {
185 BNerr(BN_F_BN_CTX_NEW, ERR_R_MALLOC_FAILURE);
188 /* Initialise the structure */
189 BN_POOL_init(&ret->pool);
190 BN_STACK_init(&ret->stack);
194 BN_CTX *BN_CTX_secure_new(void)
196 BN_CTX *ret = BN_CTX_new();
199 ret->flags = BN_FLG_SECURE;
203 void BN_CTX_free(BN_CTX *ctx)
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: ");
215 while (loop < BN_CTX_POOL_SIZE)
216 fprintf(stderr, "%02x ", pool->vals[loop++].dmax);
219 fprintf(stderr, "\n");
222 BN_STACK_finish(&ctx->stack);
223 BN_POOL_finish(&ctx->pool);
227 void BN_CTX_start(BN_CTX *ctx)
229 CTXDBG_ENTRY("BN_CTX_start", ctx);
230 /* If we're already overflowing ... */
231 if (ctx->err_stack || ctx->too_many)
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);
241 void BN_CTX_end(BN_CTX *ctx)
243 CTXDBG_ENTRY("BN_CTX_end", ctx);
247 unsigned int fp = BN_STACK_pop(&ctx->stack);
248 /* Does this stack frame have anything to release? */
250 BN_POOL_release(&ctx->pool, ctx->used - fp);
252 /* Unjam "too_many" in case "get" had failed */
258 BIGNUM *BN_CTX_get(BN_CTX *ctx)
262 CTXDBG_ENTRY("BN_CTX_get", ctx);
263 if (ctx->err_stack || ctx->too_many)
265 if ((ret = BN_POOL_get(&ctx->pool, ctx->flags)) == NULL) {
267 * Setting too_many prevents repeated "get" attempts from cluttering
271 BNerr(BN_F_BN_CTX_GET, BN_R_TOO_MANY_TEMPORARY_VARIABLES);
274 /* OK, make sure the returned bignum is "zero" */
277 CTXDBG_RET(ctx, ret);
285 static void BN_STACK_init(BN_STACK *st)
288 st->depth = st->size = 0;
291 static void BN_STACK_finish(BN_STACK *st)
293 OPENSSL_free(st->indexes);
298 static int BN_STACK_push(BN_STACK *st, unsigned int idx)
300 if (st->depth == st->size) {
302 unsigned int newsize =
303 st->size ? (st->size * 3 / 2) : BN_CTX_START_FRAMES;
304 unsigned int *newitems = OPENSSL_malloc(sizeof(*newitems) * newsize);
305 if (newitems == NULL)
308 memcpy(newitems, st->indexes, sizeof(*newitems) * st->depth);
309 OPENSSL_free(st->indexes);
310 st->indexes = newitems;
313 st->indexes[(st->depth)++] = idx;
317 static unsigned int BN_STACK_pop(BN_STACK *st)
319 return st->indexes[--(st->depth)];
326 static void BN_POOL_init(BN_POOL *p)
328 p->head = p->current = p->tail = NULL;
329 p->used = p->size = 0;
332 static void BN_POOL_finish(BN_POOL *p)
338 for (loop = 0, bn = p->head->vals; loop++ < BN_CTX_POOL_SIZE; bn++)
341 p->current = p->head->next;
342 OPENSSL_free(p->head);
343 p->head = p->current;
348 static BIGNUM *BN_POOL_get(BN_POOL *p, int flag)
353 /* Full; allocate a new pool item and link it in. */
354 if (p->used == p->size) {
355 BN_POOL_ITEM *item = OPENSSL_malloc(sizeof(*item));
358 for (loop = 0, bn = item->vals; loop++ < BN_CTX_POOL_SIZE; bn++) {
360 if ((flag & BN_FLG_SECURE) != 0)
361 BN_set_flags(bn, BN_FLG_SECURE);
363 item->prev = p->tail;
367 p->head = p->current = p->tail = item;
369 p->tail->next = item;
373 p->size += BN_CTX_POOL_SIZE;
375 /* Return the first bignum from the new pool */
380 p->current = p->head;
381 else if ((p->used % BN_CTX_POOL_SIZE) == 0)
382 p->current = p->current->next;
383 return p->current->vals + ((p->used++) % BN_CTX_POOL_SIZE);
386 static void BN_POOL_release(BN_POOL *p, unsigned int num)
388 unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;
392 bn_check_top(p->current->vals + offset);
394 offset = BN_CTX_POOL_SIZE - 1;
395 p->current = p->current->prev;