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
65 #include "cryptlib.h"
66 #include "bn_lcl.h"
67
68
BN_CTX_new(void)69 BN_CTX *BN_CTX_new(void)
70 {
71 BN_CTX *ret;
72
73 ret=(BN_CTX *)OPENSSL_malloc(sizeof(BN_CTX));
74 if (ret == NULL)
75 {
76 BNerr(BN_F_BN_CTX_NEW,ERR_R_MALLOC_FAILURE);
77 return(NULL);
78 }
79
80 BN_CTX_init(ret);
81 ret->flags=BN_FLG_MALLOCED;
82 return(ret);
83 }
84
BN_CTX_init(BN_CTX * ctx)85 void BN_CTX_init(BN_CTX *ctx)
86 {
87 #if 0 /* explicit version */
88 int i;
89 ctx->tos = 0;
90 ctx->flags = 0;
91 ctx->depth = 0;
92 ctx->too_many = 0;
93 for (i = 0; i < BN_CTX_NUM; i++)
94 BN_init(&(ctx->bn[i]));
95 #else
96 memset(ctx, 0, sizeof *ctx);
97 #endif
98 }
99
BN_CTX_free(BN_CTX * ctx)100 void BN_CTX_free(BN_CTX *ctx)
101 {
102 int i;
103
104 if (ctx == NULL) return;
105 assert(ctx->depth == 0);
106
107 for (i=0; i < BN_CTX_NUM; i++)
108 BN_clear_free(&(ctx->bn[i]));
109 if (ctx->flags & BN_FLG_MALLOCED)
110 OPENSSL_free(ctx);
111 }
112
BN_CTX_start(BN_CTX * ctx)113 void BN_CTX_start(BN_CTX *ctx)
114 {
115 if (ctx->depth < BN_CTX_NUM_POS)
116 ctx->pos[ctx->depth] = ctx->tos;
117 ctx->depth++;
118 }
119
120
BN_CTX_get(BN_CTX * ctx)121 BIGNUM *BN_CTX_get(BN_CTX *ctx)
122 {
123 /* Note: If BN_CTX_get is ever changed to allocate BIGNUMs dynamically,
124 * make sure that if BN_CTX_get fails once it will return NULL again
125 * until BN_CTX_end is called. (This is so that callers have to check
126 * only the last return value.)
127 */
128 if (ctx->depth > BN_CTX_NUM_POS || ctx->tos >= BN_CTX_NUM)
129 {
130 if (!ctx->too_many)
131 {
132 BNerr(BN_F_BN_CTX_GET,BN_R_TOO_MANY_TEMPORARY_VARIABLES);
133 /* disable error code until BN_CTX_end is called: */
134 ctx->too_many = 1;
135 }
136 return NULL;
137 }
138 return (&(ctx->bn[ctx->tos++]));
139 }
140
BN_CTX_end(BN_CTX * ctx)141 void BN_CTX_end(BN_CTX *ctx)
142 {
143 if (ctx == NULL) return;
144 assert(ctx->depth > 0);
145 if (ctx->depth == 0)
146 /* should never happen, but we can tolerate it if not in
147 * debug mode (could be a 'goto err' in the calling function
148 * before BN_CTX_start was reached) */
149 BN_CTX_start(ctx);
150
151 ctx->too_many = 0;
152 ctx->depth--;
153 if (ctx->depth < BN_CTX_NUM_POS)
154 ctx->tos = ctx->pos[ctx->depth];
155 }
156