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1 | /* | |
2 | * RFC 1521 base64 encoding/decoding | |
3 | * | |
4 | * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved | |
5 | * SPDX-License-Identifier: GPL-2.0 | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2 of the License, or | |
10 | * (at your option) any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License along | |
18 | * with this program; if not, write to the Free Software Foundation, Inc., | |
19 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
20 | * | |
21 | * This file is part of mbed TLS (https://tls.mbed.org) | |
22 | */ | |
23 | ||
24 | #if !defined(MBEDTLS_CONFIG_FILE) | |
25 | #include "mbedtls/config.h" | |
26 | #else | |
27 | #include MBEDTLS_CONFIG_FILE | |
28 | #endif | |
29 | ||
30 | #if defined(MBEDTLS_BASE64_C) | |
31 | ||
32 | #include "mbedtls/base64.h" | |
33 | ||
34 | #include <stdint.h> | |
35 | ||
36 | #if defined(MBEDTLS_SELF_TEST) | |
37 | #include <string.h> | |
38 | #if defined(MBEDTLS_PLATFORM_C) | |
39 | #include "mbedtls/platform.h" | |
40 | #else | |
41 | #include <stdio.h> | |
42 | #define mbedtls_printf printf | |
43 | #endif /* MBEDTLS_PLATFORM_C */ | |
44 | #endif /* MBEDTLS_SELF_TEST */ | |
45 | ||
46 | static const unsigned char base64_enc_map[64] = | |
47 | { | |
48 | 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', | |
49 | 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', | |
50 | 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', | |
51 | 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', | |
52 | 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', | |
53 | 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', | |
54 | '8', '9', '+', '/' | |
55 | }; | |
56 | ||
57 | static const unsigned char base64_dec_map[128] = | |
58 | { | |
59 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, | |
60 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, | |
61 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, | |
62 | 127, 127, 127, 127, 127, 127, 127, 127, 127, 127, | |
63 | 127, 127, 127, 62, 127, 127, 127, 63, 52, 53, | |
64 | 54, 55, 56, 57, 58, 59, 60, 61, 127, 127, | |
65 | 127, 64, 127, 127, 127, 0, 1, 2, 3, 4, | |
66 | 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, | |
67 | 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, | |
68 | 25, 127, 127, 127, 127, 127, 127, 26, 27, 28, | |
69 | 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, | |
70 | 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, | |
71 | 49, 50, 51, 127, 127, 127, 127, 127 | |
72 | }; | |
73 | ||
74 | #define BASE64_SIZE_T_MAX ( (size_t) -1 ) /* SIZE_T_MAX is not standard */ | |
75 | ||
76 | /* | |
77 | * Encode a buffer into base64 format | |
78 | */ | |
79 | int mbedtls_base64_encode( unsigned char *dst, size_t dlen, size_t *olen, | |
80 | const unsigned char *src, size_t slen ) | |
81 | { | |
82 | size_t i, n; | |
83 | int C1, C2, C3; | |
84 | unsigned char *p; | |
85 | ||
86 | if( slen == 0 ) | |
87 | { | |
88 | *olen = 0; | |
89 | return( 0 ); | |
90 | } | |
91 | ||
92 | n = slen / 3 + ( slen % 3 != 0 ); | |
93 | ||
94 | if( n > ( BASE64_SIZE_T_MAX - 1 ) / 4 ) | |
95 | { | |
96 | *olen = BASE64_SIZE_T_MAX; | |
97 | return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL ); | |
98 | } | |
99 | ||
100 | n *= 4; | |
101 | ||
102 | if( ( dlen < n + 1 ) || ( NULL == dst ) ) | |
103 | { | |
104 | *olen = n + 1; | |
105 | return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL ); | |
106 | } | |
107 | ||
108 | n = ( slen / 3 ) * 3; | |
109 | ||
110 | for( i = 0, p = dst; i < n; i += 3 ) | |
111 | { | |
112 | C1 = *src++; | |
113 | C2 = *src++; | |
114 | C3 = *src++; | |
115 | ||
116 | *p++ = base64_enc_map[(C1 >> 2) & 0x3F]; | |
117 | *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F]; | |
118 | *p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F]; | |
119 | *p++ = base64_enc_map[C3 & 0x3F]; | |
120 | } | |
121 | ||
122 | if( i < slen ) | |
123 | { | |
124 | C1 = *src++; | |
125 | C2 = ( ( i + 1 ) < slen ) ? *src++ : 0; | |
126 | ||
127 | *p++ = base64_enc_map[(C1 >> 2) & 0x3F]; | |
128 | *p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F]; | |
129 | ||
130 | if( ( i + 1 ) < slen ) | |
131 | *p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F]; | |
132 | else *p++ = '='; | |
133 | ||
134 | *p++ = '='; | |
135 | } | |
136 | ||
137 | *olen = p - dst; | |
138 | *p = 0; | |
139 | ||
140 | return( 0 ); | |
141 | } | |
142 | ||
143 | /* | |
144 | * Decode a base64-formatted buffer | |
145 | */ | |
146 | int mbedtls_base64_decode( unsigned char *dst, size_t dlen, size_t *olen, | |
147 | const unsigned char *src, size_t slen ) | |
148 | { | |
149 | size_t i, n; | |
150 | uint32_t j, x; | |
151 | unsigned char *p; | |
152 | ||
153 | /* First pass: check for validity and get output length */ | |
154 | for( i = n = j = 0; i < slen; i++ ) | |
155 | { | |
156 | /* Skip spaces before checking for EOL */ | |
157 | x = 0; | |
158 | while( i < slen && src[i] == ' ' ) | |
159 | { | |
160 | ++i; | |
161 | ++x; | |
162 | } | |
163 | ||
164 | /* Spaces at end of buffer are OK */ | |
165 | if( i == slen ) | |
166 | break; | |
167 | ||
168 | if( ( slen - i ) >= 2 && | |
169 | src[i] == '\r' && src[i + 1] == '\n' ) | |
170 | continue; | |
171 | ||
172 | if( src[i] == '\n' ) | |
173 | continue; | |
174 | ||
175 | /* Space inside a line is an error */ | |
176 | if( x != 0 ) | |
177 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); | |
178 | ||
179 | if( src[i] == '=' && ++j > 2 ) | |
180 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); | |
181 | ||
182 | if( src[i] > 127 || base64_dec_map[src[i]] == 127 ) | |
183 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); | |
184 | ||
185 | if( base64_dec_map[src[i]] < 64 && j != 0 ) | |
186 | return( MBEDTLS_ERR_BASE64_INVALID_CHARACTER ); | |
187 | ||
188 | n++; | |
189 | } | |
190 | ||
191 | if( n == 0 ) | |
192 | { | |
193 | *olen = 0; | |
194 | return( 0 ); | |
195 | } | |
196 | ||
197 | /* The following expression is to calculate the following formula without | |
198 | * risk of integer overflow in n: | |
199 | * n = ( ( n * 6 ) + 7 ) >> 3; | |
200 | */ | |
201 | n = ( 6 * ( n >> 3 ) ) + ( ( 6 * ( n & 0x7 ) + 7 ) >> 3 ); | |
202 | n -= j; | |
203 | ||
204 | if( dst == NULL || dlen < n ) | |
205 | { | |
206 | *olen = n; | |
207 | return( MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL ); | |
208 | } | |
209 | ||
210 | for( j = 3, n = x = 0, p = dst; i > 0; i--, src++ ) | |
211 | { | |
212 | if( *src == '\r' || *src == '\n' || *src == ' ' ) | |
213 | continue; | |
214 | ||
215 | j -= ( base64_dec_map[*src] == 64 ); | |
216 | x = ( x << 6 ) | ( base64_dec_map[*src] & 0x3F ); | |
217 | ||
218 | if( ++n == 4 ) | |
219 | { | |
220 | n = 0; | |
221 | if( j > 0 ) *p++ = (unsigned char)( x >> 16 ); | |
222 | if( j > 1 ) *p++ = (unsigned char)( x >> 8 ); | |
223 | if( j > 2 ) *p++ = (unsigned char)( x ); | |
224 | } | |
225 | } | |
226 | ||
227 | *olen = p - dst; | |
228 | ||
229 | return( 0 ); | |
230 | } | |
231 | ||
232 | #if defined(MBEDTLS_SELF_TEST) | |
233 | ||
234 | static const unsigned char base64_test_dec[64] = | |
235 | { | |
236 | 0x24, 0x48, 0x6E, 0x56, 0x87, 0x62, 0x5A, 0xBD, | |
237 | 0xBF, 0x17, 0xD9, 0xA2, 0xC4, 0x17, 0x1A, 0x01, | |
238 | 0x94, 0xED, 0x8F, 0x1E, 0x11, 0xB3, 0xD7, 0x09, | |
239 | 0x0C, 0xB6, 0xE9, 0x10, 0x6F, 0x22, 0xEE, 0x13, | |
240 | 0xCA, 0xB3, 0x07, 0x05, 0x76, 0xC9, 0xFA, 0x31, | |
241 | 0x6C, 0x08, 0x34, 0xFF, 0x8D, 0xC2, 0x6C, 0x38, | |
242 | 0x00, 0x43, 0xE9, 0x54, 0x97, 0xAF, 0x50, 0x4B, | |
243 | 0xD1, 0x41, 0xBA, 0x95, 0x31, 0x5A, 0x0B, 0x97 | |
244 | }; | |
245 | ||
246 | static const unsigned char base64_test_enc[] = | |
247 | "JEhuVodiWr2/F9mixBcaAZTtjx4Rs9cJDLbpEG8i7hPK" | |
248 | "swcFdsn6MWwINP+Nwmw4AEPpVJevUEvRQbqVMVoLlw=="; | |
249 | ||
250 | /* | |
251 | * Checkup routine | |
252 | */ | |
253 | int mbedtls_base64_self_test( int verbose ) | |
254 | { | |
255 | size_t len; | |
256 | const unsigned char *src; | |
257 | unsigned char buffer[128]; | |
258 | ||
259 | if( verbose != 0 ) | |
260 | mbedtls_printf( " Base64 encoding test: " ); | |
261 | ||
262 | src = base64_test_dec; | |
263 | ||
264 | if( mbedtls_base64_encode( buffer, sizeof( buffer ), &len, src, 64 ) != 0 || | |
265 | memcmp( base64_test_enc, buffer, 88 ) != 0 ) | |
266 | { | |
267 | if( verbose != 0 ) | |
268 | mbedtls_printf( "failed\n" ); | |
269 | ||
270 | return( 1 ); | |
271 | } | |
272 | ||
273 | if( verbose != 0 ) | |
274 | mbedtls_printf( "passed\n Base64 decoding test: " ); | |
275 | ||
276 | src = base64_test_enc; | |
277 | ||
278 | if( mbedtls_base64_decode( buffer, sizeof( buffer ), &len, src, 88 ) != 0 || | |
279 | memcmp( base64_test_dec, buffer, 64 ) != 0 ) | |
280 | { | |
281 | if( verbose != 0 ) | |
282 | mbedtls_printf( "failed\n" ); | |
283 | ||
284 | return( 1 ); | |
285 | } | |
286 | ||
287 | if( verbose != 0 ) | |
288 | mbedtls_printf( "passed\n\n" ); | |
289 | ||
290 | return( 0 ); | |
291 | } | |
292 | ||
293 | #endif /* MBEDTLS_SELF_TEST */ | |
294 | ||
295 | #endif /* MBEDTLS_BASE64_C */ |