[398] | 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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