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/*
* Copyright 2014 Vincent Sanders <vince@netsurf-browser.org>
*
* This file is part of libnsutils.
*
* Licensed under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
*/
/**
* \file
* Base64 encoding and decoding implementation.
*
* Implements RFC4648 (https://tools.ietf.org/html/rfc4648)
*/
#include <stdint.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include "nsutils/base64.h"
static const uint8_t b64_decoding_table[256] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0 - 7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 8 - F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 10 - 17 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 18 - 1F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 20 - 27 */
0xff, 0xff, 0xff, 62, 0xff, 0xff, 0xff, 63, /* 28 - 2F */
52, 53, 54, 55, 56, 57, 58, 59, /* 30 - 37 */
60, 61, 0xff, 0xff, 0xff, 64, 0xff, 0xff, /* 38 - 3F */
0xff, 0, 1, 2, 3, 4, 5, 6, /* 40 - 47 */
7, 8, 9, 10, 11, 12, 13, 14, /* 48 - 4F */
15, 16, 17, 18, 19, 20, 21, 22, /* 50 - 57 */
23, 24, 25, 0xff, 0xff, 0xff, 0xff, 0xff, /* 58 - 5F */
0xff, 26, 27, 28, 29, 30, 31, 32, /* 60 - 67 */
33, 34, 35, 36, 37, 38, 39, 40, /* 68 - 6F */
41, 42, 43, 44, 45, 46, 47, 48, /* 70 - 77 */
49, 50, 51, 0xff, 0xff, 0xff, 0xff, 0xff, /* 78 - 7F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 80 - 87 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 88 - 8F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 90 - 97 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 98 - 9F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* A0 - A7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* A8 - AF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* B0 - B7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* B8 - BF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* C0 - C7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* C8 - CF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* D0 - D7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* D8 - DF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* E0 - E7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* E8 - EF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* F0 - F7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* F8 - FF */
};
static const uint8_t b64_encoding_table[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '+', '/'};
static const uint8_t b64url_decoding_table[256] = {
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 0 - 7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 8 - F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 10 - 17 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 18 - 1F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 20 - 27 */
0xff, 0xff, 0xff, 0xff, 0xff, 62, 0xff, 0xff, /* 28 - 2F */
52, 53, 54, 55, 56, 57, 58, 59, /* 30 - 37 */
60, 61, 0xff, 0xff, 0xff, 64, 0xff, 0xff, /* 38 - 3F */
0xff, 0, 1, 2, 3, 4, 5, 6, /* 40 - 47 */
7, 8, 9, 10, 11, 12, 13, 14, /* 48 - 4F */
15, 16, 17, 18, 19, 20, 21, 22, /* 50 - 57 */
23, 24, 25, 0xff, 0xff, 0xff, 0xff, 63, /* 58 - 5F */
0xff, 26, 27, 28, 29, 30, 31, 32, /* 60 - 67 */
33, 34, 35, 36, 37, 38, 39, 40, /* 68 - 6F */
41, 42, 43, 44, 45, 46, 47, 48, /* 70 - 77 */
49, 50, 51, 0xff, 0xff, 0xff, 0xff, 0xff, /* 78 - 7F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 80 - 87 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 88 - 8F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 90 - 97 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* 98 - 9F */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* A0 - A7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* A8 - AF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* B0 - B7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* B8 - BF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* C0 - C7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* C8 - CF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* D0 - D7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* D8 - DF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* E0 - E7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* E8 - EF */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* F0 - F7 */
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, /* F8 - FF */
};
static const uint8_t b64url_encoding_table[] = {
'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f',
'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
'o', 'p', 'q', 'r', 's', 't', 'u', 'v',
'w', 'x', 'y', 'z', '0', '1', '2', '3',
'4', '5', '6', '7', '8', '9', '-', '_'};
static unsigned int mod_table[] = {0, 2, 1};
/**
* Base 64 encode data using a given encoding table.
*
* encode source data into buffer using the Base64 encoding.
*
* \param input The source data to encode.
* \param input_length The length of the source data.
* \param output The buffer to recive data into,
* \param output The output buffer
* \param output_length The size of the \a output buffer on entry updated with
* length written on exit.
* \return NSUERROR_OK on success and \a output_length updated else error code.
*/
static nsuerror
table_encode(const uint8_t *encoding_table,
const uint8_t *input,
size_t input_length,
uint8_t *encoded,
size_t *output_length)
{
size_t encoded_len;
size_t i; /* input index */
size_t j; /* output index */
encoded_len = 4 * ((input_length + 2) / 3);
if (encoded_len > *output_length) {
/* output buffer is too small */
return NSUERROR_NOSPACE;
}
for (i = 0, j = 0; i < input_length;) {
uint32_t octet_a = i < input_length ? input[i++] : 0;
uint32_t octet_b = i < input_length ? input[i++] : 0;
uint32_t octet_c = i < input_length ? input[i++] : 0;
uint32_t triple = (octet_a << 0x10) + (octet_b << 0x08) + octet_c;
encoded[j++] = encoding_table[(triple >> 3 * 6) & 0x3F];
encoded[j++] = encoding_table[(triple >> 2 * 6) & 0x3F];
encoded[j++] = encoding_table[(triple >> 1 * 6) & 0x3F];
encoded[j++] = encoding_table[(triple >> 0 * 6) & 0x3F];
}
for (i = 0; i < mod_table[input_length % 3]; i++) {
encoded[encoded_len - 1 - i] = '=';
}
*output_length = encoded_len;
return NSUERROR_OK;
}
/**
* Base 64 encode data using a given encoding table.
*
* allocate a buffer and encode source data into it using the Base64 encoding.
*
* \param input The source data to encode.
* \param input_length The length of the source data.
* \param output The buffer to recive data into, the caller must free.
* \param output_length The length of data placed in \a output
* \return NSERROR_OK on success and \a output updated else error code.
*/
static nsuerror
table_encode_alloc(const uint8_t *encoding_table,
const uint8_t *input,
size_t input_length,
uint8_t **output,
size_t *output_length)
{
uint8_t *encoded;
size_t encoded_len;
nsuerror res;
encoded_len = 4 * ((input_length + 2) / 3);
encoded = malloc(encoded_len);
if (encoded == NULL) {
return NSUERROR_NOMEM;
}
res = table_encode(encoding_table,
input,
input_length,
encoded,
&encoded_len);
if (res != NSUERROR_OK) {
free(encoded);
} else {
*output = encoded;
*output_length = encoded_len;
}
return res;
}
/*
* standard base64 encoding
*
* exported interface documented in nsutils/base64.h
*/
nsuerror
nsu_base64_encode_alloc(const uint8_t *input,
size_t input_length,
uint8_t **output,
size_t *output_length)
{
return table_encode_alloc(b64_encoding_table,
input,
input_length,
output,
output_length);
}
/*
* url base64 encoding
*
* exported interface documented in nsutils/base64.h
*/
nsuerror
nsu_base64_encode_alloc_url(const uint8_t *input,
size_t input_length,
uint8_t **output,
size_t *output_length)
{
return table_encode_alloc(b64url_encoding_table,
input,
input_length,
output,
output_length);
}
/*
* standard base64 encoding
*
* exported interface documented in nsutils/base64.h
*/
nsuerror
nsu_base64_encode(const uint8_t *input,
size_t input_length,
uint8_t *output,
size_t *output_length)
{
return table_encode(b64_encoding_table,
input,
input_length,
output,
output_length);
}
/*
* url base64 encoding
*
* exported interface documented in nsutils/base64.h
*/
nsuerror
nsu_base64_encode_url(const uint8_t *input,
size_t input_length,
uint8_t *output,
size_t *output_length)
{
return table_encode(b64url_encoding_table,
input,
input_length,
output,
output_length);
}
/**
* Base 64 decode data with a given decoding table.
*
* Allocate a buffer and decode source data into it using the Base64 decoding
* table.
*
* \param input The source data to decode.
* \param input_length The length of the source data.
* \param output The buffer to recive data into, the caller must free.
* \param output_length The length of data placed in \a output
* \return NSERROR_OK on success and \a output updated else error code.
*/
static nsuerror
base64_decode_alloc(const uint8_t *decoding_table,
const uint8_t *input,
size_t input_length,
uint8_t **output,
size_t *output_length)
{
uint8_t *decoded;
size_t decoded_len;
size_t idx;
size_t opidx;
uint8_t sextet[4];
int sextet_idx;
decoded_len = ((input_length + 3) / 4) * 3;
if (input[input_length - 1] == '=') (decoded_len)--;
if (input[input_length - 2] == '=') (decoded_len)--;
decoded = malloc(decoded_len);
if (decoded == NULL) {
return NSUERROR_NOMEM;
}
sextet_idx = 0;
idx = 0;
opidx = 0;
while (idx < input_length) {
sextet[sextet_idx] = decoding_table[input[idx++]];
if (sextet[sextet_idx] >= 64) {
/* not in encoding set */
if (sextet[sextet_idx] == 64) {
break; /* pad recived - input complete */
}
} else {
sextet_idx++;
if (sextet_idx == 4) {
if (opidx >= (decoded_len - 3)) {
break; /* insufficient output buffer space */
}
decoded[opidx++] = (sextet[0] << 2) | (sextet[1] >> 4);
decoded[opidx++] = (sextet[1] << 4) | (sextet[2] >> 2);
decoded[opidx++] = (sextet[2] << 6) | (sextet[3]);
sextet_idx = 0;
}
}
}
/* deal with any remaining recived bytes ensuring output buffer is not overrun */
switch (sextet_idx) {
case 1:
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[0] << 2);
}
break;
case 2:
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[0] << 2) | (sextet[1] >> 4);
}
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[1] << 4);
}
break;
case 3:
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[0] << 2) | (sextet[1] >> 4);
}
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[1] << 4) | (sextet[2] >> 2);
}
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[2] << 6);
}
break;
case 4:
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[0] << 2) | (sextet[1] >> 4);
}
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[1] << 4) | (sextet[2] >> 2);
}
if (opidx < decoded_len) {
decoded[opidx++] = (sextet[2] << 6) | (sextet[3]);
}
break;
}
*output = decoded;
*output_length = opidx;
return NSUERROR_OK;
}
/*
* standard base64 decoding
*
* exported interface documented in nsutils/base64.h
*/
nsuerror
nsu_base64_decode_alloc(const uint8_t *input,
size_t input_length,
uint8_t **output,
size_t *output_length)
{
return base64_decode_alloc(b64_decoding_table,
input,
input_length,
output,
output_length);
}
/*
* standard base64 decoding
*
* exported interface documented in nsutils/base64.h
*/
nsuerror
nsu_base64_decode_alloc_url(const uint8_t *input,
size_t input_length,
uint8_t **output,
size_t *output_length)
{
return base64_decode_alloc(b64url_decoding_table,
input,
input_length,
output,
output_length);
}
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