1 /* $NetBSD: base64.c,v 1.1.1.1 2011/04/13 18:15:40 elric Exp $ */
2
3 /*
4 * Copyright (c) 1995-2001 Kungliga Tekniska Högskolan
5 * (Royal Institute of Technology, Stockholm, Sweden).
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 * may be used to endorse or promote products derived from this software
21 * without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36 #include <config.h>
37
38 #include <stdlib.h>
39 #include <string.h>
40 #include <limits.h>
41 #include <krb5/base64.h>
42
43 static const char base64_chars[] =
44 "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
45
46 static int
pos(char c)47 pos(char c)
48 {
49 const char *p;
50 for (p = base64_chars; *p; p++)
51 if (*p == c)
52 return p - base64_chars;
53 return -1;
54 }
55
56 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
base64_encode(const void * data,int size,char ** str)57 base64_encode(const void *data, int size, char **str)
58 {
59 char *s, *p;
60 int i;
61 int c;
62 const unsigned char *q;
63
64 if (size > INT_MAX/4 || size < 0) {
65 *str = NULL;
66 return -1;
67 }
68
69 p = s = (char *) malloc(size * 4 / 3 + 4);
70 if (p == NULL) {
71 *str = NULL;
72 return -1;
73 }
74 q = (const unsigned char *) data;
75
76 for (i = 0; i < size;) {
77 c = q[i++];
78 c *= 256;
79 if (i < size)
80 c += q[i];
81 i++;
82 c *= 256;
83 if (i < size)
84 c += q[i];
85 i++;
86 p[0] = base64_chars[(c & 0x00fc0000) >> 18];
87 p[1] = base64_chars[(c & 0x0003f000) >> 12];
88 p[2] = base64_chars[(c & 0x00000fc0) >> 6];
89 p[3] = base64_chars[(c & 0x0000003f) >> 0];
90 if (i > size)
91 p[3] = '=';
92 if (i > size + 1)
93 p[2] = '=';
94 p += 4;
95 }
96 *p = 0;
97 *str = s;
98 return (int) strlen(s);
99 }
100
101 #define DECODE_ERROR 0xffffffff
102
103 static unsigned int
token_decode(const char * token)104 token_decode(const char *token)
105 {
106 int i;
107 unsigned int val = 0;
108 int marker = 0;
109 if (strlen(token) < 4)
110 return DECODE_ERROR;
111 for (i = 0; i < 4; i++) {
112 val *= 64;
113 if (token[i] == '=')
114 marker++;
115 else if (marker > 0)
116 return DECODE_ERROR;
117 else
118 val += pos(token[i]);
119 }
120 if (marker > 2)
121 return DECODE_ERROR;
122 return (marker << 24) | val;
123 }
124
125 ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
base64_decode(const char * str,void * data)126 base64_decode(const char *str, void *data)
127 {
128 const char *p;
129 unsigned char *q;
130
131 q = data;
132 for (p = str; *p && (*p == '=' || strchr(base64_chars, *p)); p += 4) {
133 unsigned int val = token_decode(p);
134 unsigned int marker = (val >> 24) & 0xff;
135 if (val == DECODE_ERROR)
136 return -1;
137 *q++ = (val >> 16) & 0xff;
138 if (marker < 2)
139 *q++ = (val >> 8) & 0xff;
140 if (marker < 1)
141 *q++ = val & 0xff;
142 }
143 return q - (unsigned char *) data;
144 }
145