158 lines
3.9 KiB
C
158 lines
3.9 KiB
C
/*
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* Copyright (C) 2009 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*
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* You can also choose to distribute this program under the terms of
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* the Unmodified Binary Distribution Licence (as given in the file
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* COPYING.UBDL), provided that you have satisfied its requirements.
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <string.h>
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#include <ctype.h>
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#include <errno.h>
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#include <assert.h>
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#include <ipxe/base64.h>
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/** @file
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*
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* Base64 encoding
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*
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*/
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static const char base64[64] =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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/**
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* Base64-encode data
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*
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* @v raw Raw data
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* @v raw_len Length of raw data
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* @v data Buffer
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* @v len Length of buffer
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* @ret len Encoded length
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*/
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size_t base64_encode ( const void *raw, size_t raw_len, char *data,
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size_t len ) {
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const uint8_t *raw_bytes = ( ( const uint8_t * ) raw );
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size_t raw_bit_len = ( 8 * raw_len );
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size_t used = 0;
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unsigned int bit;
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unsigned int byte;
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unsigned int shift;
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unsigned int tmp;
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for ( bit = 0 ; bit < raw_bit_len ; bit += 6, used++ ) {
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byte = ( bit / 8 );
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shift = ( bit % 8 );
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tmp = ( raw_bytes[byte] << shift );
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if ( ( byte + 1 ) < raw_len )
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tmp |= ( raw_bytes[ byte + 1 ] >> ( 8 - shift ) );
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tmp = ( ( tmp >> 2 ) & 0x3f );
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if ( used < len )
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data[used] = base64[tmp];
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}
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for ( ; ( bit % 8 ) != 0 ; bit += 6, used++ ) {
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if ( used < len )
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data[used] = '=';
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}
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if ( used < len )
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data[used] = '\0';
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if ( len )
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data[ len - 1 ] = '\0'; /* Ensure terminator exists */
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return used;
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}
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/**
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* Base64-decode string
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*
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* @v encoded Encoded string
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* @v data Buffer
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* @v len Length of buffer
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* @ret len Length of data, or negative error
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*/
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int base64_decode ( const char *encoded, void *data, size_t len ) {
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const char *in = encoded;
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uint8_t *out = data;
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uint8_t in_char;
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char *match;
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int in_bits;
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unsigned int bit = 0;
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unsigned int pad_count = 0;
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size_t offset;
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/* Zero the output buffer */
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memset ( data, 0, len );
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/* Decode string */
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while ( ( in_char = *(in++) ) ) {
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/* Ignore whitespace characters */
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if ( isspace ( in_char ) )
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continue;
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/* Process pad characters */
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if ( in_char == '=' ) {
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if ( pad_count >= 2 ) {
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DBG ( "Base64-encoded string \"%s\" has too "
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"many pad characters\n", encoded );
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return -EINVAL;
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}
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pad_count++;
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bit -= 2; /* unused_bits = ( 2 * pad_count ) */
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continue;
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}
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if ( pad_count ) {
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DBG ( "Base64-encoded string \"%s\" has invalid pad "
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"sequence\n", encoded );
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return -EINVAL;
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}
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/* Process normal characters */
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match = strchr ( base64, in_char );
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if ( ! match ) {
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DBG ( "Base64-encoded string \"%s\" contains invalid "
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"character '%c'\n", encoded, in_char );
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return -EINVAL;
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}
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in_bits = ( match - base64 );
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/* Add to raw data */
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in_bits <<= 2;
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offset = ( bit / 8 );
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if ( offset < len )
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out[offset] |= ( in_bits >> ( bit % 8 ) );
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offset++;
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if ( offset < len )
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out[offset] |= ( in_bits << ( 8 - ( bit % 8 ) ) );
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bit += 6;
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}
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/* Check that we decoded a whole number of bytes */
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if ( ( bit % 8 ) != 0 ) {
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DBG ( "Base64-encoded string \"%s\" has invalid bit length "
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"%d\n", encoded, bit );
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return -EINVAL;
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}
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/* Return length in bytes */
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return ( bit / 8 );
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}
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