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 *)OPENSSL_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 OPENSSL_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 BN_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 } 145