| /* 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 <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, BN_CTX_new, 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_CTX_start, 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_CTX_get, 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) { |
| if (st->size) |
| 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)); |
| } |
| if (st->size) { |
| 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--; |
| } |
| } |
| } |