blob: c73b1391c1b03ee14a06d2f04535e3fb6a9e3076 [file] [log] [blame]
/*
* RFC 1521 base64 encoding/decoding
*
* Copyright (C) 2018, Nordic Semiconductor ASA
* Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
* SPDX-License-Identifier: Apache-2.0
*
* Licensed under the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* Adapted for Zephyr by Carles Cufi (carles.cufi@nordicsemi.no)
* - Removed mbedtls_ prefixes
* - Reworked coding style
*/
#include <stdint.h>
#include <errno.h>
#include <sys/base64.h>
static const u8_t base64_enc_map[64] = {
'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 u8_t base64_dec_map[128] = {
127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
127, 127, 127, 127, 127, 127, 127, 127, 127, 127,
127, 127, 127, 62, 127, 127, 127, 63, 52, 53,
54, 55, 56, 57, 58, 59, 60, 61, 127, 127,
127, 64, 127, 127, 127, 0, 1, 2, 3, 4,
5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
25, 127, 127, 127, 127, 127, 127, 26, 27, 28,
29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
39, 40, 41, 42, 43, 44, 45, 46, 47, 48,
49, 50, 51, 127, 127, 127, 127, 127
};
#define BASE64_SIZE_T_MAX ((size_t) -1) /* SIZE_T_MAX is not standard */
/*
* Encode a buffer into base64 format
*/
int base64_encode(u8_t *dst, size_t dlen, size_t *olen, const u8_t *src,
size_t slen)
{
size_t i, n;
int C1, C2, C3;
u8_t *p;
if (slen == 0) {
*olen = 0;
return 0;
}
n = slen / 3 + (slen % 3 != 0);
if (n > (BASE64_SIZE_T_MAX - 1) / 4) {
*olen = BASE64_SIZE_T_MAX;
return -ENOMEM;
}
n *= 4;
if ((dlen < n + 1) || (!dst)) {
*olen = n + 1;
return -ENOMEM;
}
n = (slen / 3) * 3;
for (i = 0, p = dst; i < n; i += 3) {
C1 = *src++;
C2 = *src++;
C3 = *src++;
*p++ = base64_enc_map[(C1 >> 2) & 0x3F];
*p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];
*p++ = base64_enc_map[(((C2 & 15) << 2) + (C3 >> 6)) & 0x3F];
*p++ = base64_enc_map[C3 & 0x3F];
}
if (i < slen) {
C1 = *src++;
C2 = ((i + 1) < slen) ? *src++ : 0;
*p++ = base64_enc_map[(C1 >> 2) & 0x3F];
*p++ = base64_enc_map[(((C1 & 3) << 4) + (C2 >> 4)) & 0x3F];
if ((i + 1) < slen) {
*p++ = base64_enc_map[((C2 & 15) << 2) & 0x3F];
} else {
*p++ = '=';
}
*p++ = '=';
}
*olen = p - dst;
*p = 0U;
return 0;
}
/*
* Decode a base64-formatted buffer
*/
int base64_decode(u8_t *dst, size_t dlen, size_t *olen, const u8_t *src,
size_t slen)
{
size_t i, n;
u32_t j, x;
u8_t *p;
/* First pass: check for validity and get output length */
for (i = n = j = 0U; i < slen; i++) {
/* Skip spaces before checking for EOL */
x = 0U;
while (i < slen && src[i] == ' ') {
++i;
++x;
}
/* Spaces at end of buffer are OK */
if (i == slen) {
break;
}
if ((slen - i) >= 2 && src[i] == '\r' && src[i + 1] == '\n') {
continue;
}
if (src[i] == '\n') {
continue;
}
/* Space inside a line is an error */
if (x != 0U) {
return -EINVAL;
}
if (src[i] == '=' && ++j > 2) {
return -EINVAL;
}
if (src[i] > 127 || base64_dec_map[src[i]] == 127U) {
return -EINVAL;
}
if (base64_dec_map[src[i]] < 64 && j != 0U) {
return -EINVAL;
}
n++;
}
if (n == 0) {
*olen = 0;
return 0;
}
/* The following expression is to calculate the following formula
* without risk of integer overflow in n:
* n = ( ( n * 6 ) + 7 ) >> 3;
*/
n = (6 * (n >> 3)) + ((6 * (n & 0x7) + 7) >> 3);
n -= j;
if (dst == NULL || dlen < n) {
*olen = n;
return -ENOMEM;
}
for (j = 3U, n = x = 0U, p = dst; i > 0; i--, src++) {
if (*src == '\r' || *src == '\n' || *src == ' ') {
continue;
}
j -= (base64_dec_map[*src] == 64U);
x = (x << 6) | (base64_dec_map[*src] & 0x3F);
if (++n == 4) {
n = 0;
if (j > 0) {
*p++ = (unsigned char)(x >> 16);
}
if (j > 1) {
*p++ = (unsigned char)(x >> 8);
}
if (j > 2) {
*p++ = (unsigned char)(x);
}
}
}
*olen = p - dst;
return 0;
}