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base64.c
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base64.c
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/*-
* SSLsplit - transparent SSL/TLS interception
* https://www.roe.ch/SSLsplit
*
* Copyright (c) 2009-2019, Daniel Roethlisberger <daniel@roe.ch>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS ``AS IS''
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <stdlib.h>
#include <string.h>
/*
* Base64 encoding functions.
*/
/*
* Base64 decode insz bytes from in.
* Returns allocated buffer containing outsz bytes.
* The buffer is null-terminated, but the terminator is not included in outsz.
* If in does not contain valid Base64 encoded data, returns NULL.
* This is a very strict implementation. Any characters not within the
* Base64 alphabet are considered invalid, including newline and whitespace.
*/
unsigned char *
base64_dec(const char *in, size_t insz, size_t *outsz)
{
static const int revalphabet[] = {
-1, -1, -1, -1, -1, -1, -1, -1, /* 0 .. 7 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 8 .. 15 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 16 .. 23 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 24 .. 31 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 32 .. 39 */
-1, -1, -1, 62, -1, -1, -1, 63, /* 40 .. 47 */
52, 53, 54, 55, 56, 57, 58, 59, /* 48 .. 55 */
60, 61, -1, -1, -1, -1, -1, -1, /* 56 .. 63 */
-1, 0, 1, 2, 3, 4, 5, 6, /* 64 .. 71 */
7, 8, 9, 10, 11, 12, 13, 14, /* 72 .. 79 */
15, 16, 17, 18, 19, 20, 21, 22, /* 80 .. 87 */
23, 24, 25, -1, -1, -1, -1, -1, /* 88 .. 95 */
-1, 26, 27, 28, 29, 30, 31, 32, /* 96 .. 103 */
33, 34, 35, 36, 37, 38, 39, 40, /* 104 .. 111 */
41, 42, 43, 44, 45, 46, 47, 48, /* 112 .. 119 */
49, 50, 51, -1, -1, -1, -1, -1, /* 120 .. 127 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 128 .. 135 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 136 .. 143 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 144 .. 151 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 152 .. 159 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 160 .. 167 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 168 .. 175 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 176 .. 183 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 184 .. 191 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 192 .. 199 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 200 .. 207 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 208 .. 215 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 216 .. 223 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 224 .. 231 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 232 .. 239 */
-1, -1, -1, -1, -1, -1, -1, -1, /* 240 .. 247 */
-1, -1, -1, -1, -1, -1, -1, -1 }; /* 248 .. 255 */
size_t i, o;
int tmp, digit;
unsigned char *out;
if (insz % 4)
return NULL;
if (insz == 0) {
*outsz = 0;
return (unsigned char *)strdup("");
}
if (in[insz - 2] == '=')
*outsz = ((insz / 4) * 3) - 2;
else if (in[insz - 1] == '=')
*outsz = ((insz / 4) * 3) - 1;
else
*outsz = (insz / 4) * 3;
if (!(out = malloc((*outsz) + 1))) {
*outsz = 0;
return NULL;
}
for (i = 0, o = 0; i < insz; i += 4, o += 3) {
if ((digit = revalphabet[(unsigned char)in[i ]]) == -1)
goto leave;
tmp = digit << 18;
if ((digit = revalphabet[(unsigned char)in[i + 1]]) == -1)
goto leave;
tmp += digit << 12;
if ((digit = revalphabet[(unsigned char)in[i + 2]]) == -1) {
if ((i == insz - 4) && (in[i + 2] == '='))
digit = 0;
else
goto leave;
}
tmp += digit << 6;
if ((digit = revalphabet[(unsigned char)in[i + 3]]) == -1) {
if ((i == insz - 4) && (in[i + 3] == '='))
digit = 0;
else
goto leave;
}
tmp += digit;
out[o ] = (tmp >> 16) & 0xff;
if (o + 1 < *outsz)
out[o + 1] = (tmp >> 8) & 0xff;
if (o + 2 < *outsz)
out[o + 2] = tmp & 0xff;
}
out[*outsz] = '\0';
return out;
leave:
free(out);
return NULL;
}
/*
* Base64 encode insz bytes from in.
* Returns allocated buffer containing outsz bytes.
* The buffer is null-terminated, but the terminator is not included in outsz.
*/
char *
base64_enc(const unsigned char *in, size_t insz, size_t *outsz)
{
static const int alphabet[] = {
'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', '+', '/' };
size_t i, o;
char *out;
if (insz == 0) {
*outsz = 0;
return strdup("");
}
*outsz = ((insz + 2) / 3) * 4;
if (!(out = malloc((*outsz) + 1))) {
*outsz = 0;
return NULL;
}
for (i = 0, o = 0; i < insz; i += 3, o += 4) {
int tmp;
tmp = in[i ] << 16;
if (i + 1 < insz)
tmp += in[i + 1] << 8;
if (i + 2 < insz)
tmp += in[i + 2];
out[o ] = alphabet[(tmp >> 18) & 0x3f];
out[o + 1] = alphabet[(tmp >> 12) & 0x3f];
out[o + 2] = alphabet[(tmp >> 6) & 0x3f];
out[o + 3] = alphabet[ tmp & 0x3f];
if (i + 2 > insz)
out[o + 2] = '=';
if (i + 3 > insz)
out[o + 3] = '=';
}
out[*outsz] = '\0';
return out;
}
/* vim: set noet ft=c: */