libs/ldap/libldap/lbase64.c

   1 /* lbase64.c - routines for dealing with base64 strings */
   2 /* $OpenLDAP$ */
   3 /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   4  *
   5  * Copyright 1998-2022 The OpenLDAP Foundation.
   6  * All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted only as authorized by the OpenLDAP
  10  * Public License.
  11  *
  12  * A copy of this license is available in the file LICENSE in the
  13  * top-level directory of the distribution or, alternatively, at
  14  * <http://www.OpenLDAP.org/license.html>.
  15  */
  16 /* Portions Copyright (c) 1992-1996 Regents of the University of Michigan.
  17  * All rights reserved.
  18  *
  19  * Redistribution and use in source and binary forms are permitted
  20  * provided that this notice is preserved and that due credit is given
  21  * to the University of Michigan at Ann Arbor.  The name of the
  22  * University may not be used to endorse or promote products derived
  23  * from this software without specific prior written permission.  This
  24  * software is provided ``as is'' without express or implied warranty.
  25  */
  26 /* This work was originally developed by the University of Michigan
  27  * and distributed as part of U-MICH LDAP.
  28  */
  29
  30 #include "portable.h"
  31
  32 #include "ldap-int.h"
  33
  34 #define RIGHT2                  0x03
  35 #define RIGHT4                  0x0f
  36
  37 static const unsigned char b642nib[0x80] = {
  38         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  39         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  40         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  41         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  42         0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  43         0xff, 0xff, 0xff, 0x3e, 0xff, 0xff, 0xff, 0x3f,
  44         0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
  45         0x3c, 0x3d, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
  46         0xff, 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06,
  47         0x07, 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e,
  48         0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
  49         0x17, 0x18, 0x19, 0xff, 0xff, 0xff, 0xff, 0xff,
  50         0xff, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20,
  51         0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28,
  52         0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f, 0x30,
  53         0x31, 0x32, 0x33, 0xff, 0xff, 0xff, 0xff, 0xff
  54 };
  55
  56 int
  57 ldap_int_decode_b64_inplace( struct berval *value )
  58 {
  59         char    *p, *end, *byte;
  60         char    nib;
  61
  62         byte = value->bv_val;
  63         end = value->bv_val + value->bv_len;
  64
  65         for ( p = value->bv_val, value->bv_len = 0;
  66                 p < end;
  67                 p += 4, value->bv_len += 3 )
  68         {
  69                 int i;
  70                 for ( i = 0; i < 4; i++ ) {
  71                         if ( p[i] != '=' && (p[i] & 0x80 ||
  72                             b642nib[ p[i] & 0x7f ] > 0x3f) ) {
  73                                 Debug2( LDAP_DEBUG_ANY,
  74                                         _("ldap_pvt_decode_b64_inplace: invalid base64 encoding"
  75                                         " char (%c) 0x%x\n"), p[i], p[i] );
  76                                 return( -1 );
  77                         }
  78                 }
  79
  80                 /* first digit */
  81                 nib = b642nib[ p[0] & 0x7f ];
  82                 byte[0] = nib << 2;
  83                 /* second digit */
  84                 nib = b642nib[ p[1] & 0x7f ];
  85                 byte[0] |= nib >> 4;
  86                 byte[1] = (nib & RIGHT4) << 4;
  87                 /* third digit */
  88                 if ( p[2] == '=' ) {
  89                         value->bv_len += 1;
  90                         break;
  91                 }
  92                 nib = b642nib[ p[2] & 0x7f ];
  93                 byte[1] |= nib >> 2;
  94                 byte[2] = (nib & RIGHT2) << 6;
  95                 /* fourth digit */
  96                 if ( p[3] == '=' ) {
  97                         value->bv_len += 2;
  98                         break;
  99                 }
 100                 nib = b642nib[ p[3] & 0x7f ];
 101                 byte[2] |= nib;
 102
 103                 byte += 3;
 104         }
 105         value->bv_val[ value->bv_len ] = '\0';
 106
 107     return LDAP_SUCCESS;
 108 }