buffer.c revision 296465 
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        memset(a->data, 0, (unsigned int)a->max);
92        OPENSSL_free(a->data);
93    }
94    OPENSSL_free(a);
95}
96
97int BUF_MEM_grow(BUF_MEM *str, int len)
98{
99    char *ret;
100    unsigned int n;
101
102    if (len < 0) {
103        BUFerr(BUF_F_BUF_MEM_GROW, ERR_R_MALLOC_FAILURE);
104        return 0;
105    }
106    if (str->length >= len) {
107        str->length = len;
108        return (len);
109    }
110    if (str->max >= len) {
111        memset(&str->data[str->length], 0, len - str->length);
112        str->length = len;
113        return (len);
114    }
115    /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
116    if (len > LIMIT_BEFORE_EXPANSION) {
117        BUFerr(BUF_F_BUF_MEM_GROW, ERR_R_MALLOC_FAILURE);
118        return 0;
119    }
120    n = (len + 3) / 3 * 4;
121    if (str->data == NULL)
122        ret = OPENSSL_malloc(n);
123    else
124        ret = OPENSSL_realloc(str->data, n);
125    if (ret == NULL) {
126        BUFerr(BUF_F_BUF_MEM_GROW, ERR_R_MALLOC_FAILURE);
127        len = 0;
128    } else {
129        str->data = ret;
130        str->max = n;
131        memset(&str->data[str->length], 0, len - str->length);
132        str->length = len;
133    }
134    return (len);
135}
136
137int BUF_MEM_grow_clean(BUF_MEM *str, int len)
138{
139    char *ret;
140    unsigned int n;
141
142    if (len < 0) {
143        BUFerr(BUF_F_BUF_MEM_GROW_CLEAN, ERR_R_MALLOC_FAILURE);
144        return 0;
145    }
146    if (str->length >= len) {
147        memset(&str->data[len], 0, str->length - len);
148        str->length = len;
149        return (len);
150    }
151    if (str->max >= len) {
152        memset(&str->data[str->length], 0, len - str->length);
153        str->length = len;
154        return (len);
155    }
156    /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
157    if (len > LIMIT_BEFORE_EXPANSION) {
158        BUFerr(BUF_F_BUF_MEM_GROW_CLEAN, ERR_R_MALLOC_FAILURE);
159        return 0;
160    }
161    n = (len + 3) / 3 * 4;
162    if (str->data == NULL)
163        ret = OPENSSL_malloc(n);
164    else
165        ret = OPENSSL_realloc_clean(str->data, str->max, n);
166    if (ret == NULL) {
167        BUFerr(BUF_F_BUF_MEM_GROW_CLEAN, ERR_R_MALLOC_FAILURE);
168        len = 0;
169    } else {
170        str->data = ret;
171        str->max = n;
172        memset(&str->data[str->length], 0, len - str->length);
173        str->length = len;
174    }
175    return (len);
176}
177