buffer.c revision 296341 
1/* crypto/buffer/buffer.c */
2/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
4 *
5 * This package is an SSL implementation written
6 * by Eric Young (eay@cryptsoft.com).
7 * The implementation was written so as to conform with Netscapes SSL.
8 *
9 * This library is free for commercial and non-commercial use as long as
10 * the following conditions are aheared to.  The following conditions
11 * apply to all code found in this distribution, be it the RC4, RSA,
12 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
13 * included with this distribution is covered by the same copyright terms
14 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
15 *
16 * Copyright remains Eric Young's, and as such any Copyright notices in
17 * the code are not to be removed.
18 * If this package is used in a product, Eric Young should be given attribution
19 * as the author of the parts of the library used.
20 * This can be in the form of a textual message at program startup or
21 * in documentation (online or textual) provided with the package.
22 *
23 * Redistribution and use in source and binary forms, with or without
24 * modification, are permitted provided that the following conditions
25 * are met:
26 * 1. Redistributions of source code must retain the copyright
27 *    notice, this list of conditions and the following disclaimer.
28 * 2. Redistributions in binary form must reproduce the above copyright
29 *    notice, this list of conditions and the following disclaimer in the
30 *    documentation and/or other materials provided with the distribution.
31 * 3. All advertising materials mentioning features or use of this software
32 *    must display the following acknowledgement:
33 *    "This product includes cryptographic software written by
34 *     Eric Young (eay@cryptsoft.com)"
35 *    The word 'cryptographic' can be left out if the rouines from the library
36 *    being used are not cryptographic related :-).
37 * 4. If you include any Windows specific code (or a derivative thereof) from
38 *    the apps directory (application code) you must include an acknowledgement:
39 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40 *
41 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51 * SUCH DAMAGE.
52 *
53 * The licence and distribution terms for any publically available version or
54 * derivative of this code cannot be changed.  i.e. this code cannot simply be
55 * copied and put under another distribution licence
56 * [including the GNU Public Licence.]
57 */
58
59#include <stdio.h>
60#include "cryptlib.h"
61#include <openssl/buffer.h>
62
63/*
64 * LIMIT_BEFORE_EXPANSION is the maximum n such that (n+3)/3*4 < 2**31. That
65 * function is applied in several functions in this file and this limit
66 * ensures that the result fits in an int.
67 */
68#define LIMIT_BEFORE_EXPANSION 0x5ffffffc
69
70BUF_MEM *BUF_MEM_new(void)
71{
72    BUF_MEM *ret;
73
74    ret = OPENSSL_malloc(sizeof(BUF_MEM));
75    if (ret == NULL) {
76        BUFerr(BUF_F_BUF_MEM_NEW, ERR_R_MALLOC_FAILURE);
77        return (NULL);
78    }
79    ret->length = 0;
80    ret->max = 0;
81    ret->data = NULL;
82    return (ret);
83}
84
85void BUF_MEM_free(BUF_MEM *a)
86{
87    if (a == NULL)
88        return;
89
90    if (a->data != NULL) {
91        OPENSSL_cleanse(a->data, a->max);
92        OPENSSL_free(a->data);
93    }
94    OPENSSL_free(a);
95}
96
97int BUF_MEM_grow(BUF_MEM *str, size_t len)
98{
99    char *ret;
100    size_t n;
101
102    if (str->length >= len) {
103        str->length = len;
104        return (len);
105    }
106    if (str->max >= len) {
107        memset(&str->data[str->length], 0, len - str->length);
108        str->length = len;
109        return (len);
110    }
111    /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
112    if (len > LIMIT_BEFORE_EXPANSION) {
113        BUFerr(BUF_F_BUF_MEM_GROW, ERR_R_MALLOC_FAILURE);
114        return 0;
115    }
116    n = (len + 3) / 3 * 4;
117    if (str->data == NULL)
118        ret = OPENSSL_malloc(n);
119    else
120        ret = OPENSSL_realloc(str->data, n);
121    if (ret == NULL) {
122        BUFerr(BUF_F_BUF_MEM_GROW, ERR_R_MALLOC_FAILURE);
123        len = 0;
124    } else {
125        str->data = ret;
126        str->max = n;
127        memset(&str->data[str->length], 0, len - str->length);
128        str->length = len;
129    }
130    return (len);
131}
132
133int BUF_MEM_grow_clean(BUF_MEM *str, size_t len)
134{
135    char *ret;
136    size_t n;
137
138    if (str->length >= len) {
139        memset(&str->data[len], 0, str->length - len);
140        str->length = len;
141        return (len);
142    }
143    if (str->max >= len) {
144        memset(&str->data[str->length], 0, len - str->length);
145        str->length = len;
146        return (len);
147    }
148    /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
149    if (len > LIMIT_BEFORE_EXPANSION) {
150        BUFerr(BUF_F_BUF_MEM_GROW_CLEAN, ERR_R_MALLOC_FAILURE);
151        return 0;
152    }
153    n = (len + 3) / 3 * 4;
154    if (str->data == NULL)
155        ret = OPENSSL_malloc(n);
156    else
157        ret = OPENSSL_realloc_clean(str->data, str->max, n);
158    if (ret == NULL) {
159        BUFerr(BUF_F_BUF_MEM_GROW_CLEAN, ERR_R_MALLOC_FAILURE);
160        len = 0;
161    } else {
162        str->data = ret;
163        str->max = n;
164        memset(&str->data[str->length], 0, len - str->length);
165        str->length = len;
166    }
167    return (len);
168}
169
170void BUF_reverse(unsigned char *out, const unsigned char *in, size_t size)
171{
172    size_t i;
173    if (in) {
174        out += size - 1;
175        for (i = 0; i < size; i++)
176            *out-- = *in++;
177    } else {
178        unsigned char *q;
179        char c;
180        q = out + size - 1;
181        for (i = 0; i < size / 2; i++) {
182            c = *q;
183            *q-- = *out;
184            *out++ = c;
185        }
186    }
187}
188