sudo/plugins/sudoers/b64_decode.c

84 lines
3.1 KiB
C

/*
* SPDX-License-Identifier: ISC
*
* Copyright (c) 2013-2018 Todd C. Miller <Todd.Miller@sudo.ws>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/*
* This is an open source non-commercial project. Dear PVS-Studio, please check it.
* PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
*/
#include <config.h>
#include <sudoers.h>
/*
* Derived from code with the following declaration:
* PUBLIC DOMAIN - Jon Mayo - November 13, 2003
*/
static const unsigned char base64dec_tab[256]= {
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255, 62,255,255,255, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61,255,255,255, 0,255,255,
255, 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, 25,255,255,255,255,255,
255, 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, 51,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,
};
/*
* Decode a NUL-terminated string in base64 format and store the
* result in dst.
*/
size_t
base64_decode(const char * restrict in, unsigned char * restrict out, size_t out_size)
{
unsigned char *out_end = out + out_size;
const unsigned char *out0 = out;
unsigned int rem, v;
debug_decl(base64_decode, SUDOERS_DEBUG_MATCH);
for (v = 0, rem = 0; *in != '\0' && *in != '='; in++) {
unsigned char ch = base64dec_tab[(unsigned char)*in];
if (ch == 255)
debug_return_size_t((size_t)-1);
v = (v << 6) | ch;
rem += 6;
if (rem >= 8) {
rem -= 8;
if (out >= out_end)
debug_return_size_t((size_t)-1);
*out++ = (v >> rem) & 0xff;
}
}
if (rem >= 8) {
if (out >= out_end)
debug_return_size_t((size_t)-1);
*out++ = (v >> rem) & 0xff;
}
debug_return_size_t((size_t)(out - out0));
}