1/*	$NetBSD$	*/
2
3/*
4 * Copyright (c) 1995-2001 Kungliga Tekniska H��gskolan
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
43static const char base64_chars[] =
44    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
45
46static int
47pos(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
56ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
57base64_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
103static unsigned int
104token_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
125ROKEN_LIB_FUNCTION int ROKEN_LIB_CALL
126base64_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