wine/dlls/secur32/base64_codec.c
Kai Blin f543aea5e3 secur32: Fix wrong bit shift in the base64 encoder.
Thanks to Juan Lang for catching this one.
2006-05-27 10:55:05 +02:00

193 lines
5.7 KiB
C

/*
* base64 encoder/decoder
*
* Copyright 2005 by Kai Blin
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
*/
#include "windef.h"
#include "winerror.h"
#include "sspi.h"
#include "wine/debug.h"
WINE_DEFAULT_DEBUG_CHANNEL(secur32);
static const char b64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
SECURITY_STATUS encodeBase64(PBYTE in_buf, int in_len, char* out_buf,
int max_len, int *out_len)
{
int div, i;
PBYTE d = in_buf;
int bytes = (in_len*8 + 5)/6, pad_bytes = (bytes % 4) ? 4 - (bytes % 4) : 0;
TRACE("bytes is %d, pad bytes is %d\n", bytes, pad_bytes);
*out_len = bytes + pad_bytes;
if(bytes + pad_bytes + 1 > max_len)
return SEC_E_BUFFER_TOO_SMALL;
/* Three bytes of input give 4 chars of output */
div = in_len / 3;
i = 0;
while(div > 0)
{
/* first char is the first 6 bits of the first byte*/
out_buf[i + 0] = b64[ ( d[0] >> 2) & 0x3f ];
/* second char is the last 2 bits of the first byte and the first 4
* bits of the second byte */
out_buf[i + 1] = b64[ ((d[0] << 4) & 0x30) | (d[1] >> 4 & 0x0f)];
/* third char is the last 4 bits of the second byte and the first 2
* bits of the third byte */
out_buf[i + 2] = b64[ ((d[1] << 2) & 0x3c) | (d[2] >> 6 & 0x03)];
/* fourth char is the remaining 6 bits of the third byte */
out_buf[i + 3] = b64[ d[2] & 0x3f];
i += 4;
d += 3;
div--;
}
switch(pad_bytes)
{
case 1:
/* first char is the first 6 bits of the first byte*/
out_buf[i + 0] = b64[ ( d[0] >> 2) & 0x3f ];
/* second char is the last 2 bits of the first byte and the first 4
* bits of the second byte */
out_buf[i + 1] = b64[ ((d[0] << 4) & 0x30) | (d[1] >> 4 & 0x0f)];
/* third char is the last 4 bits of the second byte padded with
* two zeroes */
out_buf[i + 2] = b64[ ((d[1] << 2) & 0x3c) ];
/* fourth char is a = to indicate one byte of padding */
out_buf[i + 3] = '=';
out_buf[i + 4] = 0;
break;
case 2:
/* first char is the first 6 bits of the first byte*/
out_buf[i + 0] = b64[ ( d[0] >> 2) & 0x3f ];
/* second char is the last 2 bits of the first byte padded with
* four zeroes*/
out_buf[i + 1] = b64[ ((d[0] << 4) & 0x30)];
/* third char is = to indicate padding */
out_buf[i + 2] = '=';
/* fourth char is = to indicate padding */
out_buf[i + 3] = '=';
out_buf[i + 4] = 0;
break;
default:
out_buf[i] = 0;
}
return SEC_E_OK;
}
static inline BYTE decode(char c)
{
if( c >= 'A' && c <= 'Z')
return c - 'A';
if( c >= 'a' && c <= 'z')
return c - 'a' + 26;
if( c >= '0' && c <= '9')
return c - '0' + 52;
if( c == '+')
return 62;
if( c == '/')
return 63;
else
return 64;
}
SECURITY_STATUS decodeBase64(char *in_buf, int in_len, PBYTE out_buf,
int max_len, int *out_len)
{
int len = in_len, i;
char *d = in_buf;
int ip0, ip1, ip2, ip3;
TRACE("in_len: %d\n", in_len);
if((in_len % 4) != 0)
return SEC_E_INVALID_TOKEN;
if(in_len > max_len)
return SEC_E_BUFFER_TOO_SMALL;
i = 0;
while(len > 4)
{
if((ip0 = decode(d[0])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip1 = decode(d[1])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip2 = decode(d[2])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip3 = decode(d[3])) > 63)
return SEC_E_INVALID_TOKEN;
out_buf[i + 0] = (ip0 << 2) | (ip1 >> 4);
out_buf[i + 1] = (ip1 << 4) | (ip2 >> 2);
out_buf[i + 2] = (ip2 << 6) | ip3;
len -= 4;
i += 3;
d += 4;
}
if(d[2] == '=')
{
if((ip0 = decode(d[0])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip1 = decode(d[1])) > 63)
return SEC_E_INVALID_TOKEN;
out_buf[i] = (ip0 << 2) | (ip1 >> 4);
i++;
}
else if(d[3] == '=')
{
if((ip0 = decode(d[0])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip1 = decode(d[1])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip2 = decode(d[2])) > 63)
return SEC_E_INVALID_TOKEN;
out_buf[i + 0] = (ip0 << 2) | (ip1 >> 4);
out_buf[i + 1] = (ip1 << 4) | (ip2 >> 2);
i += 2;
}
else
{
if((ip0 = decode(d[0])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip1 = decode(d[1])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip2 = decode(d[2])) > 63)
return SEC_E_INVALID_TOKEN;
if((ip3 = decode(d[3])) > 63)
return SEC_E_INVALID_TOKEN;
out_buf[i + 0] = (ip0 << 2) | (ip1 >> 4);
out_buf[i + 1] = (ip1 << 4) | (ip2 >> 2);
out_buf[i + 2] = (ip2 << 6) | ip3;
i += 3;
}
*out_len = i;
return SEC_E_OK;
}