1 /*
2 * Copyright 1995-2020 The OpenSSL Project Authors. All Rights Reserved.
3 *
4 * Licensed under the Apache License 2.0 (the "License"). You may not use
5 * this file except in compliance with the License. You can obtain a copy
6 * in the file LICENSE in the source distribution or at
7 * https://www.openssl.org/source/license.html
8 */
9
10 #include <stdio.h>
11 #include "internal/cryptlib.h"
12 #include <openssl/buffer.h>
13
14 /*
15 * LIMIT_BEFORE_EXPANSION is the maximum n such that (n+3)/3*4 < 2**31. That
16 * function is applied in several functions in this file and this limit
17 * ensures that the result fits in an int.
18 */
19 #define LIMIT_BEFORE_EXPANSION 0x5ffffffc
20
BUF_MEM_new_ex(unsigned long flags)21 BUF_MEM *BUF_MEM_new_ex(unsigned long flags)
22 {
23 BUF_MEM *ret;
24
25 ret = BUF_MEM_new();
26 if (ret != NULL)
27 ret->flags = flags;
28 return ret;
29 }
30
BUF_MEM_new(void)31 BUF_MEM *BUF_MEM_new(void)
32 {
33 BUF_MEM *ret;
34
35 ret = OPENSSL_zalloc(sizeof(*ret));
36 if (ret == NULL) {
37 ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);
38 return NULL;
39 }
40 return ret;
41 }
42
BUF_MEM_free(BUF_MEM * a)43 void BUF_MEM_free(BUF_MEM *a)
44 {
45 if (a == NULL)
46 return;
47 if (a->data != NULL) {
48 if (a->flags & BUF_MEM_FLAG_SECURE)
49 OPENSSL_secure_clear_free(a->data, a->max);
50 else
51 OPENSSL_clear_free(a->data, a->max);
52 }
53 OPENSSL_free(a);
54 }
55
56 /* Allocate a block of secure memory; copy over old data if there
57 * was any, and then free it. */
sec_alloc_realloc(BUF_MEM * str,size_t len)58 static char *sec_alloc_realloc(BUF_MEM *str, size_t len)
59 {
60 char *ret;
61
62 ret = OPENSSL_secure_malloc(len);
63 if (str->data != NULL) {
64 if (ret != NULL) {
65 memcpy(ret, str->data, str->length);
66 OPENSSL_secure_clear_free(str->data, str->length);
67 str->data = NULL;
68 }
69 }
70 return ret;
71 }
72
BUF_MEM_grow(BUF_MEM * str,size_t len)73 size_t BUF_MEM_grow(BUF_MEM *str, size_t len)
74 {
75 char *ret;
76 size_t n;
77
78 if (str->length >= len) {
79 str->length = len;
80 return len;
81 }
82 if (str->max >= len) {
83 if (str->data != NULL)
84 memset(&str->data[str->length], 0, len - str->length);
85 str->length = len;
86 return len;
87 }
88 /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
89 if (len > LIMIT_BEFORE_EXPANSION) {
90 ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);
91 return 0;
92 }
93 n = (len + 3) / 3 * 4;
94 if ((str->flags & BUF_MEM_FLAG_SECURE))
95 ret = sec_alloc_realloc(str, n);
96 else
97 ret = OPENSSL_realloc(str->data, n);
98 if (ret == NULL) {
99 ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);
100 len = 0;
101 } else {
102 str->data = ret;
103 str->max = n;
104 memset(&str->data[str->length], 0, len - str->length);
105 str->length = len;
106 }
107 return len;
108 }
109
BUF_MEM_grow_clean(BUF_MEM * str,size_t len)110 size_t BUF_MEM_grow_clean(BUF_MEM *str, size_t len)
111 {
112 char *ret;
113 size_t n;
114
115 if (str->length >= len) {
116 if (str->data != NULL)
117 memset(&str->data[len], 0, str->length - len);
118 str->length = len;
119 return len;
120 }
121 if (str->max >= len) {
122 memset(&str->data[str->length], 0, len - str->length);
123 str->length = len;
124 return len;
125 }
126 /* This limit is sufficient to ensure (len+3)/3*4 < 2**31 */
127 if (len > LIMIT_BEFORE_EXPANSION) {
128 ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);
129 return 0;
130 }
131 n = (len + 3) / 3 * 4;
132 if ((str->flags & BUF_MEM_FLAG_SECURE))
133 ret = sec_alloc_realloc(str, n);
134 else
135 ret = OPENSSL_clear_realloc(str->data, str->max, n);
136 if (ret == NULL) {
137 ERR_raise(ERR_LIB_BUF, ERR_R_MALLOC_FAILURE);
138 len = 0;
139 } else {
140 str->data = ret;
141 str->max = n;
142 memset(&str->data[str->length], 0, len - str->length);
143 str->length = len;
144 }
145 return len;
146 }
147
BUF_reverse(unsigned char * out,const unsigned char * in,size_t size)148 void BUF_reverse(unsigned char *out, const unsigned char *in, size_t size)
149 {
150 size_t i;
151 if (in) {
152 out += size - 1;
153 for (i = 0; i < size; i++)
154 *out-- = *in++;
155 } else {
156 unsigned char *q;
157 char c;
158 q = out + size - 1;
159 for (i = 0; i < size / 2; i++) {
160 c = *q;
161 *q-- = *out;
162 *out++ = c;
163 }
164 }
165 }
166