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- /* Written by Ulf Moeller for the OpenSSL project. */
- /* ====================================================================
- * Copyright (c) 1998-2004 The OpenSSL Project. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- *
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in
- * the documentation and/or other materials provided with the
- * distribution.
- *
- * 3. All advertising materials mentioning features or use of this
- * software must display the following acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
- *
- * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
- * endorse or promote products derived from this software without
- * prior written permission. For written permission, please contact
- * openssl-core@openssl.org.
- *
- * 5. Products derived from this software may not be called "OpenSSL"
- * nor may "OpenSSL" appear in their names without prior written
- * permission of the OpenSSL Project.
- *
- * 6. Redistributions of any form whatsoever must retain the following
- * acknowledgment:
- * "This product includes software developed by the OpenSSL Project
- * for use in the OpenSSL Toolkit (http://www.openssl.org/)"
- *
- * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
- * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
- * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
- * OF THE POSSIBILITY OF SUCH DAMAGE.
- * ====================================================================
- *
- * This product includes cryptographic software written by Eric Young
- * (eay@cryptsoft.com). This product includes software written by Tim
- * Hudson (tjh@cryptsoft.com). */
-
-
- #include <openssl/bn.h>
-
- #include <string.h>
-
- #include <openssl/err.h>
- #include <openssl/mem.h>
-
-
- /* How many bignums are in each "pool item"; */
- #define BN_CTX_POOL_SIZE 16
- /* The stack frame info is resizing, set a first-time expansion size; */
- #define BN_CTX_START_FRAMES 32
-
- /* A bundle of bignums that can be linked with other bundles */
- typedef struct bignum_pool_item {
- /* The bignum values */
- BIGNUM vals[BN_CTX_POOL_SIZE];
- /* Linked-list admin */
- struct bignum_pool_item *prev, *next;
- } BN_POOL_ITEM;
-
-
- typedef struct bignum_pool {
- /* Linked-list admin */
- BN_POOL_ITEM *head, *current, *tail;
- /* Stack depth and allocation size */
- unsigned used, size;
- } BN_POOL;
-
- static void BN_POOL_init(BN_POOL *);
- static void BN_POOL_finish(BN_POOL *);
- static BIGNUM *BN_POOL_get(BN_POOL *);
- static void BN_POOL_release(BN_POOL *, unsigned int);
-
- /************/
- /* BN_STACK */
- /************/
-
- /* A wrapper to manage the "stack frames" */
- typedef struct bignum_ctx_stack {
- /* Array of indexes into the bignum stack */
- unsigned int *indexes;
- /* Number of stack frames, and the size of the allocated array */
- unsigned int depth, size;
- } BN_STACK;
-
- static void BN_STACK_init(BN_STACK *);
- static void BN_STACK_finish(BN_STACK *);
- static int BN_STACK_push(BN_STACK *, unsigned int);
- static unsigned int BN_STACK_pop(BN_STACK *);
-
- /**********/
- /* BN_CTX */
- /**********/
-
- /* The opaque BN_CTX type */
- struct bignum_ctx {
- /* The bignum bundles */
- BN_POOL pool;
- /* The "stack frames", if you will */
- BN_STACK stack;
- /* The number of bignums currently assigned */
- unsigned int used;
- /* Depth of stack overflow */
- int err_stack;
- /* Block "gets" until an "end" (compatibility behaviour) */
- int too_many;
- };
-
- BN_CTX *BN_CTX_new(void) {
- BN_CTX *ret = OPENSSL_malloc(sizeof(BN_CTX));
- if (!ret) {
- OPENSSL_PUT_ERROR(BN, ERR_R_MALLOC_FAILURE);
- return NULL;
- }
-
- /* Initialise the structure */
- BN_POOL_init(&ret->pool);
- BN_STACK_init(&ret->stack);
- ret->used = 0;
- ret->err_stack = 0;
- ret->too_many = 0;
- return ret;
- }
-
- void BN_CTX_free(BN_CTX *ctx) {
- if (ctx == NULL) {
- return;
- }
-
- BN_STACK_finish(&ctx->stack);
- BN_POOL_finish(&ctx->pool);
- OPENSSL_free(ctx);
- }
-
- void BN_CTX_start(BN_CTX *ctx) {
- /* If we're already overflowing ... */
- if (ctx->err_stack || ctx->too_many) {
- ctx->err_stack++;
- } else if (!BN_STACK_push(&ctx->stack, ctx->used)) {
- /* (Try to) get a new frame pointer */
- OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_TEMPORARY_VARIABLES);
- ctx->err_stack++;
- }
- }
-
- BIGNUM *BN_CTX_get(BN_CTX *ctx) {
- BIGNUM *ret;
- if (ctx->err_stack || ctx->too_many) {
- return NULL;
- }
-
- ret = BN_POOL_get(&ctx->pool);
- if (ret == NULL) {
- /* Setting too_many prevents repeated "get" attempts from
- * cluttering the error stack. */
- ctx->too_many = 1;
- OPENSSL_PUT_ERROR(BN, BN_R_TOO_MANY_TEMPORARY_VARIABLES);
- return NULL;
- }
-
- /* OK, make sure the returned bignum is "zero" */
- BN_zero(ret);
- ctx->used++;
- return ret;
- }
-
- void BN_CTX_end(BN_CTX *ctx) {
- if (ctx->err_stack) {
- ctx->err_stack--;
- } else {
- unsigned int fp = BN_STACK_pop(&ctx->stack);
- /* Does this stack frame have anything to release? */
- if (fp < ctx->used) {
- BN_POOL_release(&ctx->pool, ctx->used - fp);
- }
-
- ctx->used = fp;
- /* Unjam "too_many" in case "get" had failed */
- ctx->too_many = 0;
- }
- }
-
- /************/
- /* BN_STACK */
- /************/
-
- static void BN_STACK_init(BN_STACK *st) {
- st->indexes = NULL;
- st->depth = st->size = 0;
- }
-
- static void BN_STACK_finish(BN_STACK *st) {
- OPENSSL_free(st->indexes);
- }
-
- static int BN_STACK_push(BN_STACK *st, unsigned int idx) {
- if (st->depth == st->size) {
- /* Need to expand */
- unsigned int newsize =
- (st->size ? (st->size * 3 / 2) : BN_CTX_START_FRAMES);
- unsigned int *newitems = OPENSSL_malloc(newsize * sizeof(unsigned int));
- if (!newitems) {
- return 0;
- }
- if (st->depth) {
- memcpy(newitems, st->indexes, st->depth * sizeof(unsigned int));
- }
- OPENSSL_free(st->indexes);
- st->indexes = newitems;
- st->size = newsize;
- }
-
- st->indexes[(st->depth)++] = idx;
- return 1;
- }
-
- static unsigned int BN_STACK_pop(BN_STACK *st) {
- return st->indexes[--(st->depth)];
- }
-
- static void BN_POOL_init(BN_POOL *p) {
- p->head = p->current = p->tail = NULL;
- p->used = p->size = 0;
- }
-
- static void BN_POOL_finish(BN_POOL *p) {
- while (p->head) {
- unsigned int loop = 0;
- BIGNUM *bn = p->head->vals;
- while (loop++ < BN_CTX_POOL_SIZE) {
- if (bn->d) {
- BN_clear_free(bn);
- }
- bn++;
- }
-
- p->current = p->head->next;
- OPENSSL_free(p->head);
- p->head = p->current;
- }
- }
-
- static BIGNUM *BN_POOL_get(BN_POOL *p) {
- if (p->used == p->size) {
- BIGNUM *bn;
- unsigned int loop = 0;
- BN_POOL_ITEM *item = OPENSSL_malloc(sizeof(BN_POOL_ITEM));
- if (!item) {
- return NULL;
- }
-
- /* Initialise the structure */
- bn = item->vals;
- while (loop++ < BN_CTX_POOL_SIZE) {
- BN_init(bn++);
- }
-
- item->prev = p->tail;
- item->next = NULL;
- /* Link it in */
- if (!p->head) {
- p->head = p->current = p->tail = item;
- } else {
- p->tail->next = item;
- p->tail = item;
- p->current = item;
- }
-
- p->size += BN_CTX_POOL_SIZE;
- p->used++;
- /* Return the first bignum from the new pool */
- return item->vals;
- }
-
- if (!p->used) {
- p->current = p->head;
- } else if ((p->used % BN_CTX_POOL_SIZE) == 0) {
- p->current = p->current->next;
- }
-
- return p->current->vals + ((p->used++) % BN_CTX_POOL_SIZE);
- }
-
- static void BN_POOL_release(BN_POOL *p, unsigned int num) {
- unsigned int offset = (p->used - 1) % BN_CTX_POOL_SIZE;
- p->used -= num;
-
- while (num--) {
- if (!offset) {
- offset = BN_CTX_POOL_SIZE - 1;
- p->current = p->current->prev;
- } else {
- offset--;
- }
- }
- }
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