Line data Source code
1 : /*
2 : * Base64 encoding/decoding (RFC1341)
3 : * Copyright (c) 2005-2011, Jouni Malinen <j@w1.fi>
4 : *
5 : * This software may be distributed under the terms of the BSD license.
6 : * See README for more details.
7 : */
8 :
9 : #include "includes.h"
10 :
11 : #include "os.h"
12 : #include "base64.h"
13 :
14 : static const unsigned char base64_table[65] =
15 : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
16 :
17 : /**
18 : * base64_encode - Base64 encode
19 : * @src: Data to be encoded
20 : * @len: Length of the data to be encoded
21 : * @out_len: Pointer to output length variable, or %NULL if not used
22 : * Returns: Allocated buffer of out_len bytes of encoded data,
23 : * or %NULL on failure
24 : *
25 : * Caller is responsible for freeing the returned buffer. Returned buffer is
26 : * nul terminated to make it easier to use as a C string. The nul terminator is
27 : * not included in out_len.
28 : */
29 93 : unsigned char * base64_encode(const unsigned char *src, size_t len,
30 : size_t *out_len)
31 : {
32 : unsigned char *out, *pos;
33 : const unsigned char *end, *in;
34 : size_t olen;
35 : int line_len;
36 :
37 93 : olen = len * 4 / 3 + 4; /* 3-byte blocks to 4-byte */
38 93 : olen += olen / 72; /* line feeds */
39 93 : olen++; /* nul termination */
40 93 : if (olen < len)
41 0 : return NULL; /* integer overflow */
42 93 : out = os_malloc(olen);
43 93 : if (out == NULL)
44 0 : return NULL;
45 :
46 93 : end = src + len;
47 93 : in = src;
48 93 : pos = out;
49 93 : line_len = 0;
50 5468 : while (end - in >= 3) {
51 5282 : *pos++ = base64_table[in[0] >> 2];
52 5282 : *pos++ = base64_table[((in[0] & 0x03) << 4) | (in[1] >> 4)];
53 5282 : *pos++ = base64_table[((in[1] & 0x0f) << 2) | (in[2] >> 6)];
54 5282 : *pos++ = base64_table[in[2] & 0x3f];
55 5282 : in += 3;
56 5282 : line_len += 4;
57 5282 : if (line_len >= 72) {
58 261 : *pos++ = '\n';
59 261 : line_len = 0;
60 : }
61 : }
62 :
63 93 : if (end - in) {
64 29 : *pos++ = base64_table[in[0] >> 2];
65 29 : if (end - in == 1) {
66 14 : *pos++ = base64_table[(in[0] & 0x03) << 4];
67 14 : *pos++ = '=';
68 : } else {
69 30 : *pos++ = base64_table[((in[0] & 0x03) << 4) |
70 15 : (in[1] >> 4)];
71 15 : *pos++ = base64_table[(in[1] & 0x0f) << 2];
72 : }
73 29 : *pos++ = '=';
74 29 : line_len += 4;
75 : }
76 :
77 93 : if (line_len)
78 93 : *pos++ = '\n';
79 :
80 93 : *pos = '\0';
81 93 : if (out_len)
82 92 : *out_len = pos - out;
83 93 : return out;
84 : }
85 :
86 :
87 : /**
88 : * base64_decode - Base64 decode
89 : * @src: Data to be decoded
90 : * @len: Length of the data to be decoded
91 : * @out_len: Pointer to output length variable
92 : * Returns: Allocated buffer of out_len bytes of decoded data,
93 : * or %NULL on failure
94 : *
95 : * Caller is responsible for freeing the returned buffer.
96 : */
97 53 : unsigned char * base64_decode(const unsigned char *src, size_t len,
98 : size_t *out_len)
99 : {
100 : unsigned char dtable[256], *out, *pos, block[4], tmp;
101 : size_t i, count, olen;
102 53 : int pad = 0;
103 :
104 53 : os_memset(dtable, 0x80, 256);
105 3445 : for (i = 0; i < sizeof(base64_table) - 1; i++)
106 3392 : dtable[base64_table[i]] = (unsigned char) i;
107 53 : dtable['='] = 0;
108 :
109 53 : count = 0;
110 11068 : for (i = 0; i < len; i++) {
111 11015 : if (dtable[src[i]] != 0x80)
112 10828 : count++;
113 : }
114 :
115 53 : if (count == 0 || count % 4)
116 0 : return NULL;
117 :
118 53 : olen = count / 4 * 3;
119 53 : pos = out = os_malloc(olen);
120 53 : if (out == NULL)
121 0 : return NULL;
122 :
123 53 : count = 0;
124 11032 : for (i = 0; i < len; i++) {
125 10997 : tmp = dtable[src[i]];
126 10997 : if (tmp == 0x80)
127 169 : continue;
128 :
129 10828 : if (src[i] == '=')
130 21 : pad++;
131 10828 : block[count] = tmp;
132 10828 : count++;
133 10828 : if (count == 4) {
134 2707 : *pos++ = (block[0] << 2) | (block[1] >> 4);
135 2707 : *pos++ = (block[1] << 4) | (block[2] >> 2);
136 2707 : *pos++ = (block[2] << 6) | block[3];
137 2707 : count = 0;
138 2707 : if (pad) {
139 18 : if (pad == 1)
140 15 : pos--;
141 3 : else if (pad == 2)
142 3 : pos -= 2;
143 : else {
144 : /* Invalid padding */
145 0 : os_free(out);
146 0 : return NULL;
147 : }
148 18 : break;
149 : }
150 : }
151 : }
152 :
153 53 : *out_len = pos - out;
154 53 : return out;
155 : }
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