1/* $OpenBSD: buffer.c,v 1.28 2023/07/08 08:26:26 beck Exp $ */
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 <stdlib.h>
61#include <string.h>
62
63#include <openssl/buffer.h>
64#include <openssl/err.h>
65
66/*
67 * LIMIT_BEFORE_EXPANSION is the maximum n such that (n + 3) / 3 * 4 < 2**31.
68 * That function is applied in several functions in this file and this limit
69 * ensures that the result fits in an int.
70 */
71#define LIMIT_BEFORE_EXPANSION 0x5ffffffc
72
73BUF_MEM *
74BUF_MEM_new(void)
75{
76	BUF_MEM *ret;
77
78	if ((ret = calloc(1, sizeof(BUF_MEM))) == NULL) {
79		BUFerror(ERR_R_MALLOC_FAILURE);
80		return (NULL);
81	}
82
83	return (ret);
84}
85LCRYPTO_ALIAS(BUF_MEM_new);
86
87void
88BUF_MEM_free(BUF_MEM *a)
89{
90	if (a == NULL)
91		return;
92
93	freezero(a->data, a->max);
94	free(a);
95}
96LCRYPTO_ALIAS(BUF_MEM_free);
97
98int
99BUF_MEM_grow(BUF_MEM *str, size_t len)
100{
101	return BUF_MEM_grow_clean(str, len);
102}
103LCRYPTO_ALIAS(BUF_MEM_grow);
104
105int
106BUF_MEM_grow_clean(BUF_MEM *str, size_t len)
107{
108	char *ret;
109	size_t n;
110
111	if (str->max >= len) {
112		if (str->length >= len)
113			memset(&str->data[len], 0, str->length - len);
114		str->length = len;
115		return (len);
116	}
117
118	if (len > LIMIT_BEFORE_EXPANSION) {
119		BUFerror(ERR_R_MALLOC_FAILURE);
120		return 0;
121	}
122
123	n = (len + 3) / 3 * 4;
124	if ((ret = recallocarray(str->data, str->max, n, 1)) == NULL) {
125		BUFerror(ERR_R_MALLOC_FAILURE);
126		return (0);
127	}
128	str->data = ret;
129	str->max = n;
130	str->length = len;
131
132	return (len);
133}
134LCRYPTO_ALIAS(BUF_MEM_grow_clean);
135
136void
137BUF_reverse(unsigned char *out, const unsigned char *in, size_t size)
138{
139	size_t i;
140
141	if (in) {
142		out += size - 1;
143		for (i = 0; i < size; i++)
144			*out-- = *in++;
145	} else {
146		unsigned char *q;
147		char c;
148		q = out + size - 1;
149		for (i = 0; i < size / 2; i++) {
150			c = *q;
151			*q-- = *out;
152			*out++ = c;
153		}
154	}
155}
156