mixer: Use lsu_merge_config_file_options().
[paraslash.git] / base64.c
1 /*
2 * The code in this file was taken from openssh-5.2p1, Copyright (c) 1996 by
3 * Internet Software Consortium. Portions Copyright (c) 1995 by International
4 * Business Machines, Inc.
5 */
6
7 /** \file base64.c Uudecode and base64decode implementation. */
8
9 #include <regex.h>
10
11 #include "para.h"
12 #include "error.h"
13 #include "base64.h"
14 #include "string.h"
15
16 static const unsigned char base64_tab[256] = {
17 255, 255, 255, 255, 255, 255, 255, 255, /* 00-07 */
18 255, 255, 255, 255, 255, 255, 255, 255, /* 08-0f */
19 255, 255, 255, 255, 255, 255, 255, 255, /* 10-17 */
20 255, 255, 255, 255, 255, 255, 255, 255, /* 18-1f */
21 255, 255, 255, 255, 255, 255, 255, 255, /* 20-2f */
22 255, 255, 255, 62, 255, 255, 255, 63, /* 28-2f */
23 52 , 53, 54, 55, 56, 57, 58, 59, /* 30-37 */
24 60 , 61, 255, 255, 255, 255, 255, 255, /* 38-3f */
25 255, 0, 1, 2, 3, 4, 5, 6, /* 40-47 */
26 7 , 8, 9, 10, 11, 12, 13, 14, /* 48-4f */
27 15 , 16, 17, 18, 19, 20, 21, 22, /* 50-57 */
28 23 , 24, 25, 255, 255, 255, 255, 255, /* 58-5f */
29 255, 26, 27, 28, 29, 30, 31, 32, /* 60-6f */
30 33 , 34, 35, 36, 37, 38, 39, 40, /* 68-6f */
31 41 , 42, 43, 44, 45, 46, 47, 48, /* 70-77 */
32 49 , 50, 51, 255, 255, 255, 255, 255, /* 78-7f */
33 255, 255, 255, 255, 255, 255, 255, 255, /* 80-87 */
34 255, 255, 255, 255, 255, 255, 255, 255, /* 88-8f */
35 255, 255, 255, 255, 255, 255, 255, 255, /* 90-97 */
36 255, 255, 255, 255, 255, 255, 255, 255, /* 98-9f */
37 255, 255, 255, 255, 255, 255, 255, 255, /* a0-a7 */
38 255, 255, 255, 255, 255, 255, 255, 255, /* a8-af */
39 255, 255, 255, 255, 255, 255, 255, 255, /* b0-b7 */
40 255, 255, 255, 255, 255, 255, 255, 255, /* b8-bf */
41 255, 255, 255, 255, 255, 255, 255, 255, /* c0-c7 */
42 255, 255, 255, 255, 255, 255, 255, 255, /* c8-cf */
43 255, 255, 255, 255, 255, 255, 255, 255, /* d0-d7 */
44 255, 255, 255, 255, 255, 255, 255, 255, /* d8-df */
45 255, 255, 255, 255, 255, 255, 255, 255, /* e0-e7 */
46 255, 255, 255, 255, 255, 255, 255, 255, /* e8-ef */
47 255, 255, 255, 255, 255, 255, 255, 255, /* f0-f7 */
48 255, 255, 255, 255, 255, 255, 255, 255, /* f8-ff */
49 };
50
51 /** Maximal possible size of the decoded data. */
52 #define BASE64_MAX_DECODED_SIZE(_encoded_size) ((_encoded_size) / 4 * 3)
53
54 #define PAD64 '='
55 /**
56 * base64-decode a buffer.
57 *
58 * \param src The buffer to decode.
59 * \param encoded_size The special value -1 means: look for terminating zero byte.
60 * \param result Points to dynamically allocated target buffer on success.
61 * \param decoded_size Number of bytes written to \a result.
62 *
63 * Skips all whitespace anywhere. Converts characters, four at a time, starting
64 * at (or after) src from base - 64 numbers into three 8 bit bytes in the
65 * target area.
66 *
67 * It is OK to pass a \p NULL pointer as \a decoded_size. The result is
68 * terminated with a zero byte.
69 *
70 * \return Standard. The contents of result \a and \a decoded_size are
71 * undefined on failure.
72 */
73 int base64_decode(char const *src, size_t encoded_size, char **result,
74 size_t *decoded_size)
75 {
76 size_t i, j, state; /* source/target indices */
77 const char *end = src + encoded_size, *p;
78 unsigned char *target, uch;
79
80 if (encoded_size == (size_t)-1)
81 encoded_size = strlen(src);
82 target = para_malloc(BASE64_MAX_DECODED_SIZE(encoded_size) + 1);
83
84 for (
85 i = 0, j = 0, state = 0;
86 i < encoded_size && (uch = src[i]) != '\0';
87 i++
88 ) {
89 if (para_isspace(uch)) /* Skip whitespace anywhere. */
90 continue;
91 if (uch == PAD64)
92 break;
93 if (base64_tab[uch] == 255) /* A non-base64 character. */
94 goto fail;
95 uch = base64_tab[uch];
96 switch (state) {
97 case 0:
98 target[j] = uch << 2;
99 break;
100 case 1:
101 target[j] |= uch >> 4;
102 j++;
103 target[j] = (uch & 0x0f) << 4;
104 break;
105 case 2:
106 target[j] |= uch >> 2;
107 j++;
108 target[j] = (uch & 0x03) << 6;
109 break;
110 case 3:
111 target[j] |= uch;
112 j++;
113 break;
114 }
115 state = (state + 1) % 4;
116 }
117 p = (i < encoded_size)? src + i : NULL;
118 /*
119 * We are done decoding Base-64 chars. Let's see if we ended
120 * on a byte boundary, and/or with erroneous trailing characters.
121 */
122 if (p && *p == PAD64) { /* We got a pad char. Skip it, get next. */
123 p++;
124 switch (state) {
125 case 0: /* Invalid = in first position */
126 case 1: /* Invalid = in second position */
127 goto fail;
128
129 case 2: /* Valid, means one byte of info */
130 /* Skip any number of spaces. */
131 for (; p < end && *p != '\0'; p++)
132 if (!para_isspace(*p))
133 break;
134 /* Make sure there is another trailing = sign. */
135 if (*p != PAD64)
136 goto fail;
137 /* Fall through to "single trailing =" case. */
138 p++;
139
140 case 3: /* Valid, means two bytes of info */
141 /*
142 * We know this char is an =. Is there anything but
143 * whitespace after it?
144 */
145 for (; p < end && *p != '\0'; p++)
146 if (!para_isspace(*p))
147 goto fail;
148 /*
149 * Now make sure for cases 2 and 3 that the "extra"
150 * bits that slopped past the last full byte were
151 * zeros. If we don't check them, they become a
152 * subliminal channel.
153 */
154 if (target[j] != 0)
155 goto fail;
156 }
157 } else {
158 /*
159 * We ended by seeing the end of the string. Make sure we
160 * have no partial bytes lying around.
161 */
162 if (state != 0)
163 goto fail;
164 }
165 /* success */
166 target[j] = '\0'; /* just to be sure */
167 if (decoded_size)
168 *decoded_size = j;
169 *result = (char *)target;
170 return 1;
171 fail:
172 free(target);
173 return -E_BASE64;
174 }
175
176 /**
177 * Decode a buffer using the uuencode Base64 algorithm.
178 *
179 * \param src The buffer to decode.
180 * \param encoded_size Number of input bytes in the source buffer.
181 * \param result Contains the decoded data on success.
182 * \param decoded_size Number of output bytes on success.
183 *
184 * This is just a simple wrapper for \ref base64_decode() which strips
185 * whitespace.
186 *
187 * \return The return value of the underlying call to \ref base64_decode().
188 *
189 * \sa uuencode(1), uudecode(1).
190 */
191 int uudecode(char const *src, size_t encoded_size, char **result,
192 size_t *decoded_size)
193 {
194 const char *end = src + encoded_size, *p;
195
196 /* skip whitespace and data */
197 for (p = src; p < end && (*p == ' ' || *p == '\t'); p++)
198 ;
199 for (; p < end && *p != '\0' && *p != ' ' && *p != '\t'; p++)
200 ;
201 /* and remove trailing whitespace because base64_decode needs this */
202 return base64_decode(src, p - src, result, decoded_size);
203 }