crypto/bn/bn_ctx.c

   1 /* crypto/bn/bn_ctx.c */
   2 /* Written by Ulf Moeller for the OpenSSL project. */
   3 /* ====================================================================
   4  * Copyright (c) 1998-2000 The OpenSSL Project.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  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
  16  *    distribution.
  17  *
  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/)"
  22  *
  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.
  27  *
  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.
  31  *
  32  * 6. Redistributions of any form whatsoever must retain the following
  33  *    acknowledgment:
  34  *    "This product includes software developed by the OpenSSL Project
  35  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
  36  *
  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,
  42  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  43  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  44  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  45  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  46  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  47  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  48  * OF THE POSSIBILITY OF SUCH DAMAGE.
  49  * ====================================================================
  50  *
  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).
  54  *
  55  */
  56
  57 #ifndef BN_CTX_DEBUG
  58 # undef NDEBUG /* avoid conflicting definitions */
  59 # define NDEBUG
  60 #endif
  61
  62 #include <stdio.h>
  63 #include <assert.h>
  64 #include "cryptlib.h"
  65 #include <openssl/bn.h>
  66
  67
  68 BN_CTX *BN_CTX_new(void)
  69         {
  70         BN_CTX *ret;
  71
  72         ret=(BN_CTX *)Malloc(sizeof(BN_CTX));
  73         if (ret == NULL)
  74                 {
  75                 BNerr(BN_F_BN_CTX_NEW,ERR_R_MALLOC_FAILURE);
  76                 return(NULL);
  77                 }
  78
  79         BN_CTX_init(ret);
  80         ret->flags=BN_FLG_MALLOCED;
  81         return(ret);
  82         }
  83
  84 void BN_CTX_init(BN_CTX *ctx)
  85         {
  86         int i;
  87         ctx->tos = 0;
  88         ctx->flags = 0;
  89         ctx->depth = 0;
  90         ctx->too_many = 0;
  91         for (i = 0; i < BN_CTX_NUM; i++)
  92                 BN_init(&(ctx->bn[i]));
  93         }
  94
  95 void BN_CTX_free(BN_CTX *ctx)
  96         {
  97         int i;
  98
  99         if (ctx == NULL) return;
 100         assert(ctx->depth == 0);
 101
 102         for (i=0; i < BN_CTX_NUM; i++)
 103                 BN_clear_free(&(ctx->bn[i]));
 104         if (ctx->flags & BN_FLG_MALLOCED)
 105                 Free(ctx);
 106         }
 107
 108 void BN_CTX_start(BN_CTX *ctx)
 109         {
 110         if (ctx->depth < BN_CTX_NUM_POS)
 111                 ctx->pos[ctx->depth] = ctx->tos;
 112         ctx->depth++;
 113         }
 114
 115 BIGNUM *BN_CTX_get(BN_CTX *ctx)
 116         {
 117         if (ctx->depth > BN_CTX_NUM_POS || ctx->tos >= BN_CTX_NUM)
 118                 {
 119                 if (!ctx->too_many)
 120                         {
 121                         BNerr(BN_F_BN_CTX_GET,BN_R_TOO_MANY_TEMPORARY_VARIABLES);
 122                         /* disable error code until SSL_CTX_end is called: */
 123                         ctx->too_many = 1;
 124                         }
 125                 return NULL;
 126                 }
 127         return (&(ctx->bn[ctx->tos++]));
 128         }
 129
 130 void BN_CTX_end(BN_CTX *ctx)
 131         {
 132         if (ctx == NULL) return;
 133         assert(ctx->depth > 0);
 134         if (ctx->depth == 0)
 135                 /* should never happen, but we can tolerate it if not in
 136                  * debug mode (could be a 'goto err' in the calling function
 137                  * before BN_CTX_start was reached) */
 138                 BN_CTX_start(ctx);
 139
 140         ctx->too_many = 0;
 141         ctx->depth--;
 142         if (ctx->depth < BN_CTX_NUM_POS)
 143                 ctx->tos = ctx->pos[ctx->depth];
 144         }