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[base64] Add buffer size parameter to base64_encode() and base64_decode()

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Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2015-04-24 15:32:04 +01:00
parent 9aa8090d06
commit 1205721cbd
7 changed files with 84 additions and 77 deletions
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100
src/core/base64.c
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@@ -43,80 +43,73 @@ static const char base64[64] =
* Base64-encode data
*
* @v raw Raw data
* @v len Length of raw data
* @v encoded Buffer for encoded string
*
* The buffer must be the correct length for the encoded string. Use
* something like
*
* char buf[ base64_encoded_len ( len ) + 1 ];
*
* (the +1 is for the terminating NUL) to provide a buffer of the
* correct size.
* @v raw_len Length of raw data
* @v data Buffer
* @v len Length of buffer
* @ret len Encoded length
*/
void base64_encode ( const uint8_t *raw, size_t len, char *encoded ) {
size_t base64_encode ( const void *raw, size_t raw_len, char *data,
size_t len ) {
const uint8_t *raw_bytes = ( ( const uint8_t * ) raw );
uint8_t *encoded_bytes = ( ( uint8_t * ) encoded );
size_t raw_bit_len = ( 8 * len );
size_t raw_bit_len = ( 8 * raw_len );
size_t used = 0;
unsigned int bit;
unsigned int byte;
unsigned int shift;
unsigned int tmp;
for ( bit = 0 ; bit < raw_bit_len ; bit += 6 ) {
for ( bit = 0 ; bit < raw_bit_len ; bit += 6, used++ ) {
byte = ( bit / 8 );
shift = ( bit % 8 );
tmp = ( raw_bytes[byte] << shift );
if ( ( byte + 1 ) < len )
if ( ( byte + 1 ) < raw_len )
tmp |= ( raw_bytes[ byte + 1 ] >> ( 8 - shift ) );
tmp = ( ( tmp >> 2 ) & 0x3f );
*(encoded_bytes++) = base64[tmp];
if ( used < len )
data[used] = base64[tmp];
}
for ( ; ( bit % 8 ) != 0 ; bit += 6 )
*(encoded_bytes++) = '=';
*(encoded_bytes++) = '\0';
for ( ; ( bit % 8 ) != 0 ; bit += 6, used++ ) {
if ( used < len )
data[used] = '=';
}
if ( used < len )
data[used] = '\0';
if ( len )
data[ len - 1 ] = '\0'; /* Ensure terminator exists */
DBG ( "Base64-encoded to \"%s\":\n", encoded );
DBG_HDA ( 0, raw, len );
assert ( strlen ( encoded ) == base64_encoded_len ( len ) );
return used;
}
/**
* Base64-decode string
*
* @v encoded Encoded string
* @v raw Raw data
* @ret len Length of raw data, or negative error
*
* The buffer must be large enough to contain the decoded data. Use
* something like
*
* char buf[ base64_decoded_max_len ( encoded ) ];
*
* to provide a buffer of the correct size.
* @v data Buffer
* @v len Length of buffer
* @ret len Length of data, or negative error
*/
int base64_decode ( const char *encoded, uint8_t *raw ) {
const uint8_t *encoded_bytes = ( ( const uint8_t * ) encoded );
uint8_t *raw_bytes = ( ( uint8_t * ) raw );
uint8_t encoded_byte;
int base64_decode ( const char *encoded, void *data, size_t len ) {
const char *in = encoded;
uint8_t *out = data;
uint8_t in_char;
char *match;
int decoded;
int in_bits;
unsigned int bit = 0;
unsigned int pad_count = 0;
size_t len;
size_t offset;
/* Zero the raw data */
memset ( raw, 0, base64_decoded_max_len ( encoded ) );
/* Zero the output buffer */
memset ( data, 0, len );
/* Decode string */
while ( ( encoded_byte = *(encoded_bytes++) ) ) {
while ( ( in_char = *(in++) ) ) {
/* Ignore whitespace characters */
if ( isspace ( encoded_byte ) )
if ( isspace ( in_char ) )
continue;
/* Process pad characters */
if ( encoded_byte == '=' ) {
if ( in_char == '=' ) {
if ( pad_count >= 2 ) {
DBG ( "Base64-encoded string \"%s\" has too "
"many pad characters\n", encoded );
@@ -133,18 +126,22 @@ int base64_decode ( const char *encoded, uint8_t *raw ) {
}
/* Process normal characters */
match = strchr ( base64, encoded_byte );
match = strchr ( base64, in_char );
if ( ! match ) {
DBG ( "Base64-encoded string \"%s\" contains invalid "
"character '%c'\n", encoded, encoded_byte );
"character '%c'\n", encoded, in_char );
return -EINVAL;
}
decoded = ( match - base64 );
in_bits = ( match - base64 );
/* Add to raw data */
decoded <<= 2;
raw_bytes[ bit / 8 ] |= ( decoded >> ( bit % 8 ) );
raw_bytes[ bit / 8 + 1 ] |= ( decoded << ( 8 - ( bit % 8 ) ) );
in_bits <<= 2;
offset = ( bit / 8 );
if ( offset < len )
out[offset] |= ( in_bits >> ( bit % 8 ) );
offset++;
if ( offset < len )
out[offset] |= ( in_bits << ( 8 - ( bit % 8 ) ) );
bit += 6;
}
@@ -154,12 +151,7 @@ int base64_decode ( const char *encoded, uint8_t *raw ) {
"%d\n", encoded, bit );
return -EINVAL;
}
len = ( bit / 8 );
DBG ( "Base64-decoded \"%s\" to:\n", encoded );
DBG_HDA ( 0, raw, len );
assert ( len <= base64_decoded_max_len ( encoded ) );
/* Return length in bytes */
return ( len );
return ( bit / 8 );
}