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/*
* Copyright (c) 2013 Todd C. Miller <Todd.Miller@courtesan.com>
*
* 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.
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <config.h>
#include <sys/types.h>
#include <stdio.h>
#ifdef STDC_HEADERS
# include <stdlib.h>
# include <stddef.h>
#else
# ifdef HAVE_STDLIB_H
# include <stdlib.h>
# endif
#endif /* STDC_HEADERS */
#ifdef HAVE_STRING_H
# include <string.h>
#endif /* HAVE_STRING_H */
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif /* HAVE_STRINGS_H */
#include "missing.h"
#include "sudo_debug.h"
/*
* Decode a NUL-terminated string in base64 format and store the
* result in dst.
*/
size_t
base64_decode(const char *str, unsigned char *dst, size_t dsize)
{
static const char b64[] =
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
const unsigned char *dst0 = dst;
const unsigned char *dend = dst + dsize;
unsigned char ch[4];
char *pos;
int i;
debug_decl(base64_decode, SUDO_DEBUG_MATCH)
/*
* Convert from base64 to binary. Each base64 char holds 6 bits of data
* so 4 base64 chars equals 3 chars of data.
* Padding (with the '=' char) may or may not be present.
*/
while (*str != '\0') {
for (i = 0; i < 4; i++) {
switch (*str) {
case '=':
str++;
/* FALLTHROUGH */
case '\0':
ch[i] = '=';
break;
default:
if ((pos = strchr(b64, *str++)) == NULL)
debug_return_size_t((size_t)-1);
ch[i] = (unsigned char)(pos - b64);
break;
}
}
if (ch[0] == '=' || ch[1] == '=' || dst == dend)
break;
*dst++ = (ch[0] << 2) | ((ch[1] & 0x30) >> 4);
if (ch[2] == '=' || dst == dend)
break;
*dst++ = ((ch[1] & 0x0f) << 4) | ((ch[2] & 0x3c) >> 2);
if (ch[3] == '=' || dst == dend)
break;
*dst++ = ((ch[2] & 0x03) << 6) | ch[3];
}
debug_return_size_t((size_t)(dst - dst0));
}
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