/*
* RFC 1521 base64 encoding/decoding
*
* Copyright The Mbed TLS Contributors
* 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.
*/
#include "common.h"
#if defined(MBEDTLS_BASE64_C)
#include "mbedtls/base64.h"
#include <stdint.h>
#if defined(MBEDTLS_SELF_TEST)
#include <string.h>
#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf printf
#endif /* MBEDTLS_PLATFORM_C */
#endif /* MBEDTLS_SELF_TEST */
static const unsigned char 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 unsigned char 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 */
/*
* Constant flow conditional assignment to unsigned char
*/
static void mbedtls_base64_cond_assign_uchar(unsigned char *dest, const unsigned char *const src,
unsigned char condition) {
/* MSVC has a warning about unary minus on unsigned integer types,
* but this is well-defined and precisely what we want to do here. */
#if defined(_MSC_VER)
#pragma warning( push )
#pragma warning( disable : 4146 )
#endif
/* Generate bitmask from condition, mask will either be 0xFF or 0 */
unsigned char mask = (condition | -condition);
mask >>= 7;
mask = -mask;
#if defined(_MSC_VER)
#pragma warning( pop )
#endif
*dest = ((*src) & mask) | ((*dest) & ~mask);
}
/*
* Constant flow conditional assignment to uint_32
*/
static void mbedtls_base64_cond_assign_uint32(uint32_t *dest, const uint32_t src,
uint32_t condition) {
/* MSVC has a warning about unary minus on unsigned integer types,
* but this is well-defined and precisely what we want to do here. */
#if defined(_MSC_VER)
#pragma warning( push )
#pragma warning( disable : 4146 )
#endif
/* Generate bitmask from condition, mask will either be 0xFFFFFFFF or 0 */
uint32_t mask = (condition | -condition);
mask >>= 31;
mask = -mask;
#if defined(_MSC_VER)
#pragma warning( pop )
#endif
*dest = (src & mask) | ((*dest) & ~mask);
}
/*
* Constant flow check for equality
*/
static unsigned char mbedtls_base64_eq(size_t in_a, size_t in_b) {
size_t difference = in_a ^ in_b;
/* MSVC has a warning about unary minus on unsigned integer types,
* but this is well-defined and precisely what we want to do here. */
#if defined(_MSC_VER)
#pragma warning( push )
#pragma warning( disable : 4146 )
#endif
difference |= -difference;
#if defined(_MSC_VER)
#pragma warning( pop )
#endif
/* cope with the varying size of size_t per platform */
difference >>= (sizeof(difference) * 8 - 1);
return (unsigned char)(1 ^ difference);
}
/*
* Constant flow lookup into table.
*/
static unsigned char mbedtls_base64_table_lookup(const unsigned char *const table,
const size_t table_size, const size_t table_index) {
size_t i;
unsigned char result = 0;
for (i = 0; i < table_size; ++i) {
mbedtls_base64_cond_assign_uchar(&result, &table[i], mbedtls_base64_eq(i, table_index));
}
return result;
}
/*
* Encode a buffer into base64 format
*/
int mbedtls_base64_encode(unsigned char *dst, size_t dlen, size_t *olen,
const unsigned char *src, size_t slen) {
size_t i, n;
int C1, C2, C3;
unsigned char *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 (MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL);
}
n *= 4;
if ((dlen < n + 1) || (NULL == dst)) {
*olen = n + 1;
return (MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL);
}
n = (slen / 3) * 3;
for (i = 0, p = dst; i < n; i += 3) {
C1 = *src++;
C2 = *src++;
C3 = *src++;
*p++ = mbedtls_base64_table_lookup(base64_enc_map, sizeof(base64_enc_map),
((C1 >> 2) & 0x3F));
*p++ = mbedtls_base64_table_lookup(base64_enc_map, sizeof(base64_enc_map),
((((C1 & 3) << 4) + (C2 >> 4)) & 0x3F));
*p++ = mbedtls_base64_table_lookup(base64_enc_map, sizeof(base64_enc_map),
((((C2 & 15) << 2) + (C3 >> 6)) & 0x3F));
*p++ = mbedtls_base64_table_lookup(base64_enc_map, sizeof(base64_enc_map),
(C3 & 0x3F));
}
if (i < slen) {
C1 = *src++;
C2 = ((i + 1) < slen) ? *src++ : 0;
*p++ = mbedtls_base64_table_lookup(base64_enc_map, sizeof(base64_enc_map),
((C1 >> 2) & 0x3F));
*p++ = mbedtls_base64_table_lookup(base64_enc_map, sizeof(base64_enc_map),
((((C1 & 3) << 4) + (C2 >> 4)) & 0x3F));
if ((i + 1) < slen)
*p++ = mbedtls_base64_table_lookup(base64_enc_map, sizeof(base64_enc_map),
(((C2 & 15) << 2) & 0x3F));
else *p++ = '=';
*p++ = '=';
}
*olen = p - dst;
*p = 0;
return (0);
}
/*
* Decode a base64-formatted buffer
*/
int mbedtls_base64_decode(unsigned char *dst, size_t dlen, size_t *olen,
const unsigned char *src, size_t slen) {
size_t i, n;
uint32_t j, x;
unsigned char *p;
unsigned char dec_map_lookup;
/* First pass: check for validity and get output length */
for (i = n = j = 0; i < slen; i++) {
/* Skip spaces before checking for EOL */
x = 0;
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 != 0)
return (MBEDTLS_ERR_BASE64_INVALID_CHARACTER);
if (src[i] == '=' && ++j > 2)
return (MBEDTLS_ERR_BASE64_INVALID_CHARACTER);
dec_map_lookup = mbedtls_base64_table_lookup(base64_dec_map, sizeof(base64_dec_map), src[i]);
if (src[i] > 127 || dec_map_lookup == 127)
return (MBEDTLS_ERR_BASE64_INVALID_CHARACTER);
if (dec_map_lookup < 64 && j != 0)
return (MBEDTLS_ERR_BASE64_INVALID_CHARACTER);
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 (MBEDTLS_ERR_BASE64_BUFFER_TOO_SMALL);
}
for (j = 3, n = x = 0, p = dst; i > 0; i--, src++) {
if (*src == '\r' || *src == '\n' || *src == ' ')
continue;
dec_map_lookup = mbedtls_base64_table_lookup(base64_dec_map, sizeof(base64_dec_map), *src);
mbedtls_base64_cond_assign_uint32(&j, j - 1, mbedtls_base64_eq(dec_map_lookup, 64));
x = (x << 6) | (dec_map_lookup & 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);
}
#if defined(MBEDTLS_SELF_TEST)
static const unsigned char base64_test_dec[64] = {
0x24, 0x48, 0x6E, 0x56, 0x87, 0x62, 0x5A, 0xBD,
0xBF, 0x17, 0xD9, 0xA2, 0xC4, 0x17, 0x1A, 0x01,
0x94, 0xED, 0x8F, 0x1E, 0x11, 0xB3, 0xD7, 0x09,
0x0C, 0xB6, 0xE9, 0x10, 0x6F, 0x22, 0xEE, 0x13,
0xCA, 0xB3, 0x07, 0x05, 0x76, 0xC9, 0xFA, 0x31,
0x6C, 0x08, 0x34, 0xFF, 0x8D, 0xC2, 0x6C, 0x38,
0x00, 0x43, 0xE9, 0x54, 0x97, 0xAF, 0x50, 0x4B,
0xD1, 0x41, 0xBA, 0x95, 0x31, 0x5A, 0x0B, 0x97
};
static const unsigned char base64_test_enc[] =
"JEhuVodiWr2/F9mixBcaAZTtjx4Rs9cJDLbpEG8i7hPK"
"swcFdsn6MWwINP+Nwmw4AEPpVJevUEvRQbqVMVoLlw==";
/*
* Checkup routine
*/
int mbedtls_base64_self_test(int verbose) {
size_t len;
const unsigned char *src;
unsigned char buffer[128];
if (verbose != 0)
mbedtls_printf(" Base64 encoding test: ");
src = base64_test_dec;
if (mbedtls_base64_encode(buffer, sizeof(buffer), &len, src, 64) != 0 ||
memcmp(base64_test_enc, buffer, 88) != 0) {
if (verbose != 0)
mbedtls_printf("failed\n");
return (1);
}
if (verbose != 0)
mbedtls_printf("passed\n Base64 decoding test: ");
src = base64_test_enc;
if (mbedtls_base64_decode(buffer, sizeof(buffer), &len, src, 88) != 0 ||
memcmp(base64_test_dec, buffer, 64) != 0) {
if (verbose != 0)
mbedtls_printf("failed\n");
return (1);
}
if (verbose != 0)
mbedtls_printf("passed\n\n");
return (0);
}
#endif /* MBEDTLS_SELF_TEST */
#endif /* MBEDTLS_BASE64_C */