1/*	$NetBSD: lbase64.c,v 1.2 2021/08/14 16:14:56 christos Exp $	*/
2
3/* lbase64.c - routines for dealing with base64 strings */
4/* $OpenLDAP$ */
5/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
6 *
7 * Copyright 1998-2021 The OpenLDAP Foundation.
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted only as authorized by the OpenLDAP
12 * Public License.
13 *
14 * A copy of this license is available in the file LICENSE in the
15 * top-level directory of the distribution or, alternatively, at
16 * <http://www.OpenLDAP.org/license.html>.
17 */
18/* Portions Copyright (c) 1992-1996 Regents of the University of Michigan.
19 * All rights reserved.
20 *
21 * Redistribution and use in source and binary forms are permitted
22 * provided that this notice is preserved and that due credit is given
23 * to the University of Michigan at Ann Arbor.  The name of the
24 * University may not be used to endorse or promote products derived
25 * from this software without specific prior written permission.  This
26 * software is provided ``as is'' without express or implied warranty.
27 */
28/* This work was originally developed by the University of Michigan
29 * and distributed as part of U-MICH LDAP.
30 */
31
32#include <sys/cdefs.h>
33__RCSID("$NetBSD: lbase64.c,v 1.2 2021/08/14 16:14:56 christos Exp $");
34
35#include "portable.h"
36
37#include "ldap-int.h"
38
39#define RIGHT2			0x03
40#define RIGHT4			0x0f
41
42static const unsigned char b642nib[0x80] = {
43	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
44	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
45	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
46	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
47	0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
48	0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
49	0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
50	0x3c, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
51	0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
52	0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
53	0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
54	0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
55	0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
56	0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
57	0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
58	0x31, 0x32, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff
59};
60
61int
62ldap_int_decode_b64_inplace( struct berval *value )
63{
64	char	*p, *end, *byte;
65	char	nib;
66
67	byte = value->bv_val;
68	end = value->bv_val + value->bv_len;
69
70	for ( p = value->bv_val, value->bv_len = 0;
71		p < end;
72		p += 4, value->bv_len += 3 )
73	{
74		int i;
75		for ( i = 0; i < 4; i++ ) {
76			if ( p[i] != '=' && (p[i] & 0x80 ||
77			    b642nib[ p[i] & 0x7f ] > 0x3f) ) {
78				Debug2( LDAP_DEBUG_ANY,
79					_("ldap_pvt_decode_b64_inplace: invalid base64 encoding"
80					" char (%c) 0x%x\n"), p[i], p[i] );
81				return( -1 );
82			}
83		}
84
85		/* first digit */
86		nib = b642nib[ p[0] & 0x7f ];
87		byte[0] = nib << 2;
88		/* second digit */
89		nib = b642nib[ p[1] & 0x7f ];
90		byte[0] |= nib >> 4;
91		byte[1] = (nib & RIGHT4) << 4;
92		/* third digit */
93		if ( p[2] == '=' ) {
94			value->bv_len += 1;
95			break;
96		}
97		nib = b642nib[ p[2] & 0x7f ];
98		byte[1] |= nib >> 2;
99		byte[2] = (nib & RIGHT2) << 6;
100		/* fourth digit */
101		if ( p[3] == '=' ) {
102			value->bv_len += 2;
103			break;
104		}
105		nib = b642nib[ p[3] & 0x7f ];
106		byte[2] |= nib;
107
108		byte += 3;
109	}
110	value->bv_val[ value->bv_len ] = '\0';
111
112    return LDAP_SUCCESS;
113}
114