diff options
Diffstat (limited to 'openssl/crypto/bn/bn_ctx.c')
| -rw-r--r-- | openssl/crypto/bn/bn_ctx.c | 454 |
1 files changed, 454 insertions, 0 deletions
diff --git a/openssl/crypto/bn/bn_ctx.c b/openssl/crypto/bn/bn_ctx.c new file mode 100644 index 000000000..b3452f1a9 --- /dev/null +++ b/openssl/crypto/bn/bn_ctx.c @@ -0,0 +1,454 @@ +/* crypto/bn/bn_ctx.c */ +/* 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). + * + */ + +#if !defined(BN_CTX_DEBUG) && !defined(BN_DEBUG) +#ifndef NDEBUG +#define NDEBUG +#endif +#endif + +#include <stdio.h> +#include <assert.h> + +#include "cryptlib.h" +#include "bn_lcl.h" + +/* TODO list + * + * 1. Check a bunch of "(words+1)" type hacks in various bignum functions and + * check they can be safely removed. + * - Check +1 and other ugliness in BN_from_montgomery() + * + * 2. Consider allowing a BN_new_ex() that, at least, lets you specify an + * appropriate 'block' size that will be honoured by bn_expand_internal() to + * prevent piddly little reallocations. OTOH, profiling bignum expansions in + * BN_CTX doesn't show this to be a big issue. + */ + +/* 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 + +/***********/ +/* BN_POOL */ +/***********/ + +/* 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; +/* A linked-list of bignums grouped in bundles */ +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 *); +#ifndef OPENSSL_NO_DEPRECATED +static void BN_POOL_reset(BN_POOL *); +#endif +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 *); +#ifndef OPENSSL_NO_DEPRECATED +static void BN_STACK_reset(BN_STACK *); +#endif +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; + }; + +/* Enable this to find BN_CTX bugs */ +#ifdef BN_CTX_DEBUG +static const char *ctxdbg_cur = NULL; +static void ctxdbg(BN_CTX *ctx) + { + unsigned int bnidx = 0, fpidx = 0; + BN_POOL_ITEM *item = ctx->pool.head; + BN_STACK *stack = &ctx->stack; + fprintf(stderr,"(%08x): ", (unsigned int)ctx); + while(bnidx < ctx->used) + { + fprintf(stderr,"%02x ", item->vals[bnidx++ % BN_CTX_POOL_SIZE].dmax); + if(!(bnidx % BN_CTX_POOL_SIZE)) + item = item->next; + } + fprintf(stderr,"\n"); + bnidx = 0; + fprintf(stderr," : "); + while(fpidx < stack->depth) + { + while(bnidx++ < stack->indexes[fpidx]) + fprintf(stderr," "); + fprintf(stderr,"^^ "); + bnidx++; + fpidx++; + } + fprintf(stderr,"\n"); + } +#define CTXDBG_ENTRY(str, ctx) do { \ + ctxdbg_cur = (str); \ + fprintf(stderr,"Starting %s\n", ctxdbg_cur); \ + ctxdbg(ctx); \ + } while(0) +#define CTXDBG_EXIT(ctx) do { \ + fprintf(stderr,"Ending %s\n", ctxdbg_cur); \ + ctxdbg(ctx); \ + } while(0) +#define CTXDBG_RET(ctx,ret) +#else +#define CTXDBG_ENTRY(str, ctx) +#define CTXDBG_EXIT(ctx) +#define CTXDBG_RET(ctx,ret) +#endif + +/* This function is an evil legacy and should not be used. This implementation + * is WYSIWYG, though I've done my best. */ +#ifndef OPENSSL_NO_DEPRECATED +void BN_CTX_init(BN_CTX *ctx) + { + /* Assume the caller obtained the context via BN_CTX_new() and so is + * trying to reset it for use. Nothing else makes sense, least of all + * binary compatibility from a time when they could declare a static + * variable. */ + BN_POOL_reset(&ctx->pool); + BN_STACK_reset(&ctx->stack); + ctx->used = 0; + ctx->err_stack = 0; + ctx->too_many = 0; + } +#endif + +BN_CTX *BN_CTX_new(void) + { + BN_CTX *ret = OPENSSL_malloc(sizeof(BN_CTX)); + if(!ret) + { + BNerr(BN_F_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; +#ifdef BN_CTX_DEBUG + { + BN_POOL_ITEM *pool = ctx->pool.head; + fprintf(stderr,"BN_CTX_free, stack-size=%d, pool-bignums=%d\n", + ctx->stack.size, ctx->pool.size); + fprintf(stderr,"dmaxs: "); + while(pool) { + unsigned loop = 0; + while(loop < BN_CTX_POOL_SIZE) + fprintf(stderr,"%02x ", pool->vals[loop++].dmax); + pool = pool->next; + } + fprintf(stderr,"\n"); + } +#endif + BN_STACK_finish(&ctx->stack); + BN_POOL_finish(&ctx->pool); + OPENSSL_free(ctx); + } + +void BN_CTX_start(BN_CTX *ctx) + { + CTXDBG_ENTRY("BN_CTX_start", ctx); + /* If we're already overflowing ... */ + if(ctx->err_stack || ctx->too_many) + ctx->err_stack++; + /* (Try to) get a new frame pointer */ + else if(!BN_STACK_push(&ctx->stack, ctx->used)) + { + BNerr(BN_F_BN_CTX_START,BN_R_TOO_MANY_TEMPORARY_VARIABLES); + ctx->err_stack++; + } + CTXDBG_EXIT(ctx); + } + +void BN_CTX_end(BN_CTX *ctx) + { + CTXDBG_ENTRY("BN_CTX_end", 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; + } + CTXDBG_EXIT(ctx); + } + +BIGNUM *BN_CTX_get(BN_CTX *ctx) + { + BIGNUM *ret; + CTXDBG_ENTRY("BN_CTX_get", ctx); + if(ctx->err_stack || ctx->too_many) return NULL; + if((ret = BN_POOL_get(&ctx->pool)) == NULL) + { + /* Setting too_many prevents repeated "get" attempts from + * cluttering the error stack. */ + ctx->too_many = 1; + BNerr(BN_F_BN_CTX_GET,BN_R_TOO_MANY_TEMPORARY_VARIABLES); + return NULL; + } + /* OK, make sure the returned bignum is "zero" */ + BN_zero(ret); + ctx->used++; + CTXDBG_RET(ctx, ret); + return ret; + } + +/************/ +/* 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); + } + +#ifndef OPENSSL_NO_DEPRECATED +static void BN_STACK_reset(BN_STACK *st) + { + st->depth = 0; + } +#endif + +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)]; + } + +/***********/ +/* BN_POOL */ +/***********/ + +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; + } + } + +#ifndef OPENSSL_NO_DEPRECATED +static void BN_POOL_reset(BN_POOL *p) + { + BN_POOL_ITEM *item = p->head; + while(item) + { + unsigned int loop = 0; + BIGNUM *bn = item->vals; + while(loop++ < BN_CTX_POOL_SIZE) + { + if(bn->d) BN_clear(bn); + bn++; + } + item = item->next; + } + p->current = p->head; + p->used = 0; + } +#endif + +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--) + { + bn_check_top(p->current->vals + offset); + if(!offset) + { + offset = BN_CTX_POOL_SIZE - 1; + p->current = p->current->prev; + } + else + offset--; + } + } + |