1 | /*
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2 | * RFC 1521 base64 encoding/decoding
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3 | *
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4 | * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
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5 | * SPDX-License-Identifier: Apache-2.0
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6 | *
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7 | * Licensed under the Apache License, Version 2.0 (the "License"); you may
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8 | * not use this file except in compliance with the License.
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9 | * You may obtain a copy of the License at
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10 | *
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11 | * http://www.apache.org/licenses/LICENSE-2.0
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12 | *
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13 | * Unless required by applicable law or agreed to in writing, software
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14 | * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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15 | * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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16 | * See the License for the specific language governing permissions and
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17 | * limitations under the License.
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18 | *
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19 | * This file is part of mbed TLS (https://tls.mbed.org)
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20 | */
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21 |
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22 | #if !defined(MBEDTLS_CONFIG_FILE)
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23 | #include "mbedtls/config.h"
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24 | #else
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25 | #include MBEDTLS_CONFIG_FILE
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26 | #endif
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27 |
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28 | #if defined(MBEDTLS_BASE64_C)
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29 |
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30 | #include "mbedtls/base64.h"
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31 |
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32 | #include <stdint.h>
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33 |
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34 | #if defined(MBEDTLS_SELF_TEST)
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35 | #include <string.h>
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36 | #if defined(MBEDTLS_PLATFORM_C)
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37 | #include "mbedtls/platform.h"
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38 | #else
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39 | #include <stdio.h>
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40 | #define mbedtls_printf printf
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41 | #endif /* MBEDTLS_PLATFORM_C */
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42 | #endif /* MBEDTLS_SELF_TEST */
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43 |
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44 | static const unsigned char base64_enc_map[64] =
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45 | {
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46 | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
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47 | 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
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48 | 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd',
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49 | 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
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50 | 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
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51 | 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7',
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52 | '8', '9', '+', '/'
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53 | };
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54 |
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55 | static const unsigned char base64_dec_map[128] =
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56 | {
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57 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
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58 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
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59 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
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60 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
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61 | 127, 127, 127, 62, 127, 127, 127, 63, 52, 53,
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62 | 54, 55, 56, 57, 58, 59, 60, 61, 127, 127,
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63 | 127, 64, 127, 127, 127, 0, 1, 2, 3, 4,
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64 | 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
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65 | 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
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66 | 25, 127, 127, 127, 127, 127, 127, 26, 27, 28,
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67 | 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
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68 | 39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
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69 | 49, 50, 51, 127, 127, 127, 127, 127
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70 | };
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71 |
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72 | #define BASE64_SIZE_T_MAX ( (size_t) -1 ) /* SIZE_T_MAX is not standard */
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73 |
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74 | /*
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75 | * Encode a buffer into base64 format
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76 | */
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77 | int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen,
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78 | const unsigned char *src, size_t slen )
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79 | {
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80 | size_t i, n;
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81 | int C1, C2, C3;
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82 | unsigned char *p;
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83 |
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84 | if( slen == 0 )
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85 | {
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86 | *olen = 0;
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87 | return( 0 );
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88 | }
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89 |
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90 | n = slen / 3 + ( slen % 3 != 0 );
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91 |
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92 | if( n > ( BASE64_SIZE_T_MAX - 1 ) / 4 )
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93 | {
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94 | *olen = BASE64_SIZE_T_MAX;
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95 | return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
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96 | }
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97 |
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98 | n *= 4;
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99 |
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100 | if( ( dlen < n + 1 ) || ( NULL == dst ) )
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101 | {
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102 | *olen = n + 1;
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103 | return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
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104 | }
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105 |
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106 | n = ( slen / 3 ) * 3;
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107 |
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108 | for( i = 0, p = dst; i < n; i += 3 )
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109 | {
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110 | C1 = *src++;
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111 | C2 = *src++;
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112 | C3 = *src++;
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113 |
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114 | *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
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115 | *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];
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116 | *p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F];
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117 | *p++ = base64_enc_map[C3 & 0x3F];
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118 | }
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119 |
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120 | if( i < slen )
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121 | {
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122 | C1 = *src++;
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123 | C2 = ( ( i + 1 ) < slen ) ? *src++ : 0;
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124 |
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125 | *p++ = base64_enc_map[(C1 >> 2) & 0x3F];
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126 | *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];
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127 |
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128 | if( ( i + 1 ) < slen )
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129 | *p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F];
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130 | else *p++ = '=';
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131 |
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132 | *p++ = '=';
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133 | }
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134 |
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135 | *olen = p - dst;
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136 | *p = 0;
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137 |
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138 | return( 0 );
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139 | }
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140 |
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141 | /*
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142 | * Decode a base64-formatted buffer
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143 | */
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144 | int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen,
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145 | const unsigned char *src, size_t slen )
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146 | {
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147 | size_t i, n;
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148 | uint32_t j, x;
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149 | unsigned char *p;
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150 |
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151 | /* First pass: check for validity and get output length */
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152 | for( i = n = j = 0; i < slen; i++ )
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153 | {
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154 | /* Skip spaces before checking for EOL */
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155 | x = 0;
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156 | while( i < slen && src[i] == ' ' )
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157 | {
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158 | ++i;
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159 | ++x;
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160 | }
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161 |
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162 | /* Spaces at end of buffer are OK */
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163 | if( i == slen )
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164 | break;
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165 |
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166 | if( ( slen - i ) >= 2 &&
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167 | src[i] == '\r' && src[i + 1] == '\n' )
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168 | continue;
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169 |
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170 | if( src[i] == '\n' )
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171 | continue;
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172 |
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173 | /* Space inside a line is an error */
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174 | if( x != 0 )
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175 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
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176 |
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177 | if( src[i] == '=' && ++j > 2 )
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178 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
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179 |
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180 | if( src[i] > 127 || base64_dec_map[src[i]] == 127 )
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181 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
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182 |
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183 | if( base64_dec_map[src[i]] < 64 && j != 0 )
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184 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER );
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185 |
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186 | n++;
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187 | }
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188 |
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189 | if( n == 0 )
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190 | {
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191 | *olen = 0;
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192 | return( 0 );
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193 | }
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194 |
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195 | /* The following expression is to calculate the following formula without
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196 | * risk of integer overflow in n:
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197 | * n = ( ( n * 6 ) + 7 ) >> 3;
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198 | */
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199 | n = ( 6 * ( n >> 3 ) ) + ( ( 6 * ( n & 0x7 ) + 7 ) >> 3 );
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200 | n -= j;
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201 |
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202 | if( dst == NULL || dlen < n )
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203 | {
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204 | *olen = n;
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205 | return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL );
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206 | }
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207 |
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208 | for( j = 3, n = x = 0, p = dst; i > 0; i--, src++ )
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209 | {
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210 | if( *src == '\r' || *src == '\n' || *src == ' ' )
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211 | continue;
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212 |
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213 | j -= ( base64_dec_map[*src] == 64 );
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214 | x = ( x << 6 ) | ( base64_dec_map[*src] & 0x3F );
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215 |
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216 | if( ++n == 4 )
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217 | {
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218 | n = 0;
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219 | if( j > 0 ) *p++ = (unsigned char)( x >> 16 );
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220 | if( j > 1 ) *p++ = (unsigned char)( x >> 8 );
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221 | if( j > 2 ) *p++ = (unsigned char)( x );
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222 | }
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223 | }
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224 |
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225 | *olen = p - dst;
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226 |
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227 | return( 0 );
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228 | }
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229 |
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230 | #if defined(MBEDTLS_SELF_TEST)
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231 |
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232 | static const unsigned char base64_test_dec[64] =
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233 | {
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234 | 0x24, 0x48, 0x6E, 0x56, 0x87, 0x62, 0x5A, 0xBD,
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235 | 0xBF, 0x17, 0xD9, 0xA2, 0xC4, 0x17, 0x1A, 0x01,
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236 | 0x94, 0xED, 0x8F, 0x1E, 0x11, 0xB3, 0xD7, 0x09,
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237 | 0x0C, 0xB6, 0xE9, 0x10, 0x6F, 0x22, 0xEE, 0x13,
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238 | 0xCA, 0xB3, 0x07, 0x05, 0x76, 0xC9, 0xFA, 0x31,
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239 | 0x6C, 0x08, 0x34, 0xFF, 0x8D, 0xC2, 0x6C, 0x38,
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240 | 0x00, 0x43, 0xE9, 0x54, 0x97, 0xAF, 0x50, 0x4B,
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241 | 0xD1, 0x41, 0xBA, 0x95, 0x31, 0x5A, 0x0B, 0x97
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242 | };
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243 |
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244 | static const unsigned char base64_test_enc[] =
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245 | "JEhuVodiWr2/F9mixBcaAZTtjx4Rs9cJDLbpEG8i7hPK"
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246 | "swcFdsn6MWwINP+Nwmw4AEPpVJevUEvRQbqVMVoLlw==";
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247 |
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248 | /*
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249 | * Checkup routine
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250 | */
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251 | int mbedtls_base64_self_test( int verbose )
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252 | {
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253 | size_t len;
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254 | const unsigned char *src;
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255 | unsigned char buffer[128];
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256 |
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257 | if( verbose != 0 )
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258 | mbedtls_printf( " Base64 encoding test: " );
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259 |
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260 | src = base64_test_dec;
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261 |
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262 | if( mbedtls_base64_encode( buffer, sizeof( buffer ), &len, src, 64 ) != 0 ||
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263 | memcmp( base64_test_enc, buffer, 88 ) != 0 )
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264 | {
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265 | if( verbose != 0 )
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266 | mbedtls_printf( "failed\n" );
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267 |
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268 | return( 1 );
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269 | }
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270 |
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271 | if( verbose != 0 )
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272 | mbedtls_printf( "passed\n Base64 decoding test: " );
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273 |
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274 | src = base64_test_enc;
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275 |
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276 | if( mbedtls_base64_decode( buffer, sizeof( buffer ), &len, src, 88 ) != 0 ||
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277 | memcmp( base64_test_dec, buffer, 64 ) != 0 )
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278 | {
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279 | if( verbose != 0 )
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280 | mbedtls_printf( "failed\n" );
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281 |
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282 | return( 1 );
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283 | }
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284 |
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285 | if( verbose != 0 )
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286 | mbedtls_printf( "passed\n\n" );
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287 |
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288 | return( 0 );
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289 | }
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290 |
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291 | #endif /* MBEDTLS_SELF_TEST */
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292 |
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293 | #endif /* MBEDTLS_BASE64_C */
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