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 */
base64_encode(const unsigned char * src,size_t len,size_t * out_len)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 out = os_malloc(olen);
47 if (out == NULL)
48 return NULL;
49
50 end = src + len;
51 in = src;
52 pos = out;
53 line_len = 0;
54 while (end - in >= 3) {
55 *pos++ = base64_table[in[0] >> 2];
56 *pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
57 *pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
58 *pos++ = base64_table[in[2] & 0x3f];
59 in += 3;
60 line_len += 4;
61 if (line_len >= 72) {
62 *pos++ = '\n';
63 line_len = 0;
64 }
65 }
66
67 if (end - in) {
68 *pos++ = base64_table[in[0] >> 2];
69 if (end - in == 1) {
70 *pos++ = base64_table[(in[0] & 0x03) << 4];
71 *pos++ = '=';
72 } else {
73 *pos++ = base64_table[((in[0] & 0x03) << 4) |
74 (in[1] >> 4)];
75 *pos++ = base64_table[(in[1] & 0x0f) << 2];
76 }
77 *pos++ = '=';
78 line_len += 4;
79 }
80
81 if (line_len)
82 *pos++ = '\n';
83
84 *pos = '\0';
85 if (out_len)
86 *out_len = pos - out;
87 return out;
88 }
89
90
91 /**
92 * base64_decode - Base64 decode
93 * @src: Data to be decoded
94 * @len: Length of the data to be decoded
95 * @out_len: Pointer to output length variable
96 * Returns: Allocated buffer of out_len bytes of decoded data,
97 * or %NULL on failure
98 *
99 * Caller is responsible for freeing the returned buffer.
100 */
base64_decode(const unsigned char * src,size_t len,size_t * out_len)101 unsigned char * base64_decode(const unsigned char *src, size_t len,
102 size_t *out_len)
103 {
104 unsigned char dtable[256], *out, *pos, in[4], block[4], tmp;
105 size_t i, count, olen;
106
107 os_memset(dtable, 0x80, 256);
108 for (i = 0; i < sizeof(base64_table) - 1; i++)
109 dtable[base64_table[i]] = (unsigned char) i;
110 dtable['='] = 0;
111
112 count = 0;
113 for (i = 0; i < len; i++) {
114 if (dtable[src[i]] != 0x80)
115 count++;
116 }
117
118 if (count == 0 || count % 4)
119 return NULL;
120
121 olen = count / 4 * 3;
122 pos = out = os_malloc(olen);
123 if (out == NULL)
124 return NULL;
125
126 count = 0;
127 for (i = 0; i < len; i++) {
128 tmp = dtable[src[i]];
129 if (tmp == 0x80)
130 continue;
131
132 in[count] = src[i];
133 block[count] = tmp;
134 count++;
135 if (count == 4) {
136 *pos++ = (block[0] << 2) | (block[1] >> 4);
137 *pos++ = (block[1] << 4) | (block[2] >> 2);
138 *pos++ = (block[2] << 6) | block[3];
139 count = 0;
140 }
141 }
142
143 if (pos > out) {
144 if (in[2] == '=')
145 pos -= 2;
146 else if (in[3] == '=')
147 pos--;
148 }
149
150 *out_len = pos - out;
151 return out;
152 }
153
154
155 #ifdef TEST_MAIN
156 #include <stdio.h>
157
main(int argc,char * argv[])158 int main(int argc, char *argv[])
159 {
160 FILE *f;
161 size_t len, elen;
162 unsigned char *buf, *e;
163
164 if (argc != 4) {
165 printf("Usage: base64 <encode|decode> <in file> <out file>\n");
166 return -1;
167 }
168
169 buf = os_readfile(argv[2], &len);
170 if (buf == NULL)
171 return -1;
172
173 if (strcmp(argv[1], "encode") == 0)
174 e = base64_encode(buf, len, &elen);
175 else
176 e = base64_decode(buf, len, &elen);
177 if (e == NULL)
178 return -2;
179 f = fopen(argv[3], "w");
180 if (f == NULL)
181 return -3;
182 fwrite(e, 1, elen, f);
183 fclose(f);
184 free(e);
185
186 return 0;
187 }
188 #endif /* TEST_MAIN */
189