1 /* crypto/bn/bn_ctx.c */
2 /* Written by Ulf Moeller for the OpenSSL project. */
3 /* ====================================================================
4 * Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved.
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
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
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/)"
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.
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.
32 * 6. Redistributions of any form whatsoever must retain the following
34 * "This product includes software developed by the OpenSSL Project
35 * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
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,
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43 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
44 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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49 * ====================================================================
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).
57 #if !defined(BN_CTX_DEBUG) && !defined(BN_DEBUG)
63 #define OPENSSL_FIPSAPI
72 #include <openssl/fips.h>
77 * 1. Check a bunch of "(words+1)" type hacks in various bignum functions and
78 * check they can be safely removed.
79 * - Check +1 and other ugliness in BN_from_montgomery()
81 * 2. Consider allowing a BN_new_ex() that, at least, lets you specify an
82 * appropriate 'block' size that will be honoured by bn_expand_internal() to
83 * prevent piddly little reallocations. OTOH, profiling bignum expansions in
84 * BN_CTX doesn't show this to be a big issue.
87 /* How many bignums are in each "pool item"; */
88 #define BN_CTX_POOL_SIZE 16
89 /* The stack frame info is resizing, set a first-time expansion size; */
90 #define BN_CTX_START_FRAMES 32
96 /* A bundle of bignums that can be linked with other bundles */
97 typedef struct bignum_pool_item
99 /* The bignum values */
100 BIGNUM vals[BN_CTX_POOL_SIZE];
101 /* Linked-list admin */
102 struct bignum_pool_item *prev, *next;
104 /* A linked-list of bignums grouped in bundles */
105 typedef struct bignum_pool
107 /* Linked-list admin */
108 BN_POOL_ITEM *head, *current, *tail;
109 /* Stack depth and allocation size */
112 static void BN_POOL_init(BN_POOL *);
113 static void BN_POOL_finish(BN_POOL *);
114 #ifndef OPENSSL_NO_DEPRECATED
115 static void BN_POOL_reset(BN_POOL *);
117 static BIGNUM * BN_POOL_get(BN_POOL *);
118 static void BN_POOL_release(BN_POOL *, unsigned int);
124 /* A wrapper to manage the "stack frames" */
125 typedef struct bignum_ctx_stack
127 /* Array of indexes into the bignum stack */
128 unsigned int *indexes;
129 /* Number of stack frames, and the size of the allocated array */
130 unsigned int depth, size;
132 static void BN_STACK_init(BN_STACK *);
133 static void BN_STACK_finish(BN_STACK *);
134 #ifndef OPENSSL_NO_DEPRECATED
135 static void BN_STACK_reset(BN_STACK *);
137 static int BN_STACK_push(BN_STACK *, unsigned int);
138 static unsigned int BN_STACK_pop(BN_STACK *);
144 /* The opaque BN_CTX type */
147 /* The bignum bundles */
149 /* The "stack frames", if you will */
151 /* The number of bignums currently assigned */
153 /* Depth of stack overflow */
155 /* Block "gets" until an "end" (compatibility behaviour) */
159 /* Enable this to find BN_CTX bugs */
161 static const char *ctxdbg_cur = NULL;
162 static void ctxdbg(BN_CTX *ctx)
164 unsigned int bnidx = 0, fpidx = 0;
165 BN_POOL_ITEM *item = ctx->pool.head;
166 BN_STACK *stack = &ctx->stack;
167 fprintf(stderr,"(%08x): ", (unsigned int)ctx);
168 while(bnidx < ctx->used)
170 fprintf(stderr,"%03x ", item->vals[bnidx++ % BN_CTX_POOL_SIZE].dmax);
171 if(!(bnidx % BN_CTX_POOL_SIZE))
174 fprintf(stderr,"\n");
176 fprintf(stderr," : ");
177 while(fpidx < stack->depth)
179 while(bnidx++ < stack->indexes[fpidx])
181 fprintf(stderr,"^^^ ");
185 fprintf(stderr,"\n");
187 #define CTXDBG_ENTRY(str, ctx) do { \
188 ctxdbg_cur = (str); \
189 fprintf(stderr,"Starting %s\n", ctxdbg_cur); \
192 #define CTXDBG_EXIT(ctx) do { \
193 fprintf(stderr,"Ending %s\n", ctxdbg_cur); \
196 #define CTXDBG_RET(ctx,ret)
198 #define CTXDBG_ENTRY(str, ctx)
199 #define CTXDBG_EXIT(ctx)
200 #define CTXDBG_RET(ctx,ret)
203 /* This function is an evil legacy and should not be used. This implementation
204 * is WYSIWYG, though I've done my best. */
205 #ifndef OPENSSL_NO_DEPRECATED
206 void BN_CTX_init(BN_CTX *ctx)
208 /* Assume the caller obtained the context via BN_CTX_new() and so is
209 * trying to reset it for use. Nothing else makes sense, least of all
210 * binary compatibility from a time when they could declare a static
212 BN_POOL_reset(&ctx->pool);
213 BN_STACK_reset(&ctx->stack);
220 BN_CTX *BN_CTX_new(void)
222 BN_CTX *ret = OPENSSL_malloc(sizeof(BN_CTX));
225 BNerr(BN_F_BN_CTX_NEW,ERR_R_MALLOC_FAILURE);
228 /* Initialise the structure */
229 BN_POOL_init(&ret->pool);
230 BN_STACK_init(&ret->stack);
237 void BN_CTX_free(BN_CTX *ctx)
243 BN_POOL_ITEM *pool = ctx->pool.head;
244 fprintf(stderr,"BN_CTX_free, stack-size=%d, pool-bignums=%d\n",
245 ctx->stack.size, ctx->pool.size);
246 fprintf(stderr,"dmaxs: ");
249 while(loop < BN_CTX_POOL_SIZE)
250 fprintf(stderr,"%02x ", pool->vals[loop++].dmax);
253 fprintf(stderr,"\n");
256 BN_STACK_finish(&ctx->stack);
257 BN_POOL_finish(&ctx->pool);
261 void BN_CTX_start(BN_CTX *ctx)
263 CTXDBG_ENTRY("BN_CTX_start", ctx);
264 /* If we're already overflowing ... */
265 if(ctx->err_stack || ctx->too_many)
267 /* (Try to) get a new frame pointer */
268 else if(!BN_STACK_push(&ctx->stack, ctx->used))
270 BNerr(BN_F_BN_CTX_START,BN_R_TOO_MANY_TEMPORARY_VARIABLES);
276 void BN_CTX_end(BN_CTX *ctx)
278 CTXDBG_ENTRY("BN_CTX_end", ctx);
283 unsigned int fp = BN_STACK_pop(&ctx->stack);
284 /* Does this stack frame have anything to release? */
286 BN_POOL_release(&ctx->pool, ctx->used - fp);
288 /* Unjam "too_many" in case "get" had failed */
294 BIGNUM *BN_CTX_get(BN_CTX *ctx)
297 CTXDBG_ENTRY("BN_CTX_get", ctx);
298 if(ctx->err_stack || ctx->too_many) return NULL;
299 if((ret = BN_POOL_get(&ctx->pool)) == NULL)
301 /* Setting too_many prevents repeated "get" attempts from
302 * cluttering the error stack. */
304 BNerr(BN_F_BN_CTX_GET,BN_R_TOO_MANY_TEMPORARY_VARIABLES);
307 /* OK, make sure the returned bignum is "zero" */
310 CTXDBG_RET(ctx, ret);
318 static void BN_STACK_init(BN_STACK *st)
321 st->depth = st->size = 0;
324 static void BN_STACK_finish(BN_STACK *st)
326 if(st->size) OPENSSL_free(st->indexes);
329 #ifndef OPENSSL_NO_DEPRECATED
330 static void BN_STACK_reset(BN_STACK *st)
336 static int BN_STACK_push(BN_STACK *st, unsigned int idx)
338 if(st->depth == st->size)
341 unsigned int newsize = (st->size ?
342 (st->size * 3 / 2) : BN_CTX_START_FRAMES);
343 unsigned int *newitems = OPENSSL_malloc(newsize *
344 sizeof(unsigned int));
345 if(!newitems) return 0;
347 memcpy(newitems, st->indexes, st->depth *
348 sizeof(unsigned int));
349 if(st->size) OPENSSL_free(st->indexes);
350 st->indexes = newitems;
353 st->indexes[(st->depth)++] = idx;
357 static unsigned int BN_STACK_pop(BN_STACK *st)
359 return st->indexes[--(st->depth)];
366 static void BN_POOL_init(BN_POOL *p)
368 p->head = p->current = p->tail = NULL;
369 p->used = p->size = 0;
372 static void BN_POOL_finish(BN_POOL *p)
376 unsigned int loop = 0;
377 BIGNUM *bn = p->head->vals;
378 while(loop++ < BN_CTX_POOL_SIZE)
380 if(bn->d) BN_clear_free(bn);
383 p->current = p->head->next;
384 OPENSSL_free(p->head);
385 p->head = p->current;
389 #ifndef OPENSSL_NO_DEPRECATED
390 static void BN_POOL_reset(BN_POOL *p)
392 BN_POOL_ITEM *item = p->head;
395 unsigned int loop = 0;
396 BIGNUM *bn = item->vals;
397 while(loop++ < BN_CTX_POOL_SIZE)
399 if(bn->d) BN_clear(bn);
404 p->current = p->head;
409 static BIGNUM *BN_POOL_get(BN_POOL *p)
411 if(p->used == p->size)
414 unsigned int loop = 0;
415 BN_POOL_ITEM *item = OPENSSL_malloc(sizeof(BN_POOL_ITEM));
416 if(!item) return NULL;
417 /* Initialise the structure */
419 while(loop++ < BN_CTX_POOL_SIZE)
421 item->prev = p->tail;
425 p->head = p->current = p->tail = item;
428 p->tail->next = item;
432 p->size += BN_CTX_POOL_SIZE;
434 /* Return the first bignum from the new pool */
438 p->current = p->head;
439 else if((p->used % BN_CTX_POOL_SIZE) == 0)
440 p->current = p->current->next;
441 return p->current->vals + ((p->used++) % BN_CTX_POOL_SIZE);
444 static void BN_POOL_release(BN_POOL *p, unsigned int num)
446 unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;
450 bn_check_top(p->current->vals + offset);
453 offset = BN_CTX_POOL_SIZE - 1;
454 p->current = p->current->prev;