Dmitry Shmidt | 8d520ff | 2011-05-09 14:06:53 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * Base64 encoding/decoding (RFC1341) |
| 3 | * Copyright (c) 2005, Jouni Malinen <j@w1.fi> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | * |
| 9 | * Alternatively, this software may be distributed under the terms of BSD |
| 10 | * license. |
| 11 | * |
| 12 | * See README and COPYING for more details. |
| 13 | */ |
| 14 | |
| 15 | #include "includes.h" |
| 16 | |
| 17 | #include "os.h" |
| 18 | #include "base64.h" |
| 19 | |
| 20 | static const unsigned char base64_table[65] = |
| 21 | "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"; |
| 22 | |
| 23 | /** |
| 24 | * base64_encode - Base64 encode |
| 25 | * @src: Data to be encoded |
| 26 | * @len: Length of the data to be encoded |
| 27 | * @out_len: Pointer to output length variable, or %NULL if not used |
| 28 | * Returns: Allocated buffer of out_len bytes of encoded data, |
| 29 | * or %NULL on failure |
| 30 | * |
| 31 | * Caller is responsible for freeing the returned buffer. Returned buffer is |
| 32 | * nul terminated to make it easier to use as a C string. The nul terminator is |
| 33 | * not included in out_len. |
| 34 | */ |
| 35 | unsigned char * base64_encode(const unsigned char *src, size_t len, |
| 36 | size_t *out_len) |
| 37 | { |
| 38 | unsigned char *out, *pos; |
| 39 | const unsigned char *end, *in; |
| 40 | size_t olen; |
| 41 | int line_len; |
| 42 | |
| 43 | olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */ |
| 44 | olen += olen / 72; /* line feeds */ |
| 45 | olen++; /* nul termination */ |
| 46 | if (olen < len) |
| 47 | return NULL; /* integer overflow */ |
| 48 | out = os_malloc(olen); |
| 49 | if (out == NULL) |
| 50 | return NULL; |
| 51 | |
| 52 | end = src + len; |
| 53 | in = src; |
| 54 | pos = out; |
| 55 | line_len = 0; |
| 56 | while (end - in >= 3) { |
| 57 | *pos++ = base64_table[in[0] >> 2]; |
| 58 | *pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)]; |
| 59 | *pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)]; |
| 60 | *pos++ = base64_table[in[2] & 0x3f]; |
| 61 | in += 3; |
| 62 | line_len += 4; |
| 63 | if (line_len >= 72) { |
| 64 | *pos++ = '\n'; |
| 65 | line_len = 0; |
| 66 | } |
| 67 | } |
| 68 | |
| 69 | if (end - in) { |
| 70 | *pos++ = base64_table[in[0] >> 2]; |
| 71 | if (end - in == 1) { |
| 72 | *pos++ = base64_table[(in[0] & 0x03) << 4]; |
| 73 | *pos++ = '='; |
| 74 | } else { |
| 75 | *pos++ = base64_table[((in[0] & 0x03) << 4) | |
| 76 | (in[1] >> 4)]; |
| 77 | *pos++ = base64_table[(in[1] & 0x0f) << 2]; |
| 78 | } |
| 79 | *pos++ = '='; |
| 80 | line_len += 4; |
| 81 | } |
| 82 | |
| 83 | if (line_len) |
| 84 | *pos++ = '\n'; |
| 85 | |
| 86 | *pos = '\0'; |
| 87 | if (out_len) |
| 88 | *out_len = pos - out; |
| 89 | return out; |
| 90 | } |
| 91 | |
| 92 | |
| 93 | /** |
| 94 | * base64_decode - Base64 decode |
| 95 | * @src: Data to be decoded |
| 96 | * @len: Length of the data to be decoded |
| 97 | * @out_len: Pointer to output length variable |
| 98 | * Returns: Allocated buffer of out_len bytes of decoded data, |
| 99 | * or %NULL on failure |
| 100 | * |
| 101 | * Caller is responsible for freeing the returned buffer. |
| 102 | */ |
| 103 | unsigned char * base64_decode(const unsigned char *src, size_t len, |
| 104 | size_t *out_len) |
| 105 | { |
| 106 | unsigned char dtable[256], *out, *pos, in[4], block[4], tmp; |
| 107 | size_t i, count, olen; |
| 108 | |
| 109 | os_memset(dtable, 0x80, 256); |
| 110 | for (i = 0; i < sizeof(base64_table) - 1; i++) |
| 111 | dtable[base64_table[i]] = (unsigned char) i; |
| 112 | dtable['='] = 0; |
| 113 | |
| 114 | count = 0; |
| 115 | for (i = 0; i < len; i++) { |
| 116 | if (dtable[src[i]] != 0x80) |
| 117 | count++; |
| 118 | } |
| 119 | |
| 120 | if (count == 0 || count % 4) |
| 121 | return NULL; |
| 122 | |
| 123 | olen = count / 4 * 3; |
| 124 | pos = out = os_malloc(olen); |
| 125 | if (out == NULL) |
| 126 | return NULL; |
| 127 | |
| 128 | count = 0; |
| 129 | for (i = 0; i < len; i++) { |
| 130 | tmp = dtable[src[i]]; |
| 131 | if (tmp == 0x80) |
| 132 | continue; |
| 133 | |
| 134 | in[count] = src[i]; |
| 135 | block[count] = tmp; |
| 136 | count++; |
| 137 | if (count == 4) { |
| 138 | *pos++ = (block[0] << 2) | (block[1] >> 4); |
| 139 | *pos++ = (block[1] << 4) | (block[2] >> 2); |
| 140 | *pos++ = (block[2] << 6) | block[3]; |
| 141 | count = 0; |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | if (pos > out) { |
| 146 | if (in[2] == '=') |
| 147 | pos -= 2; |
| 148 | else if (in[3] == '=') |
| 149 | pos--; |
| 150 | } |
| 151 | |
| 152 | *out_len = pos - out; |
| 153 | return out; |
| 154 | } |