mirror of
https://git.openldap.org/openldap/openldap.git
synced 2024-12-27 03:20:22 +08:00
309 lines
9.6 KiB
C
309 lines
9.6 KiB
C
/* base64.c -- routines to encode/decode base64 data */
|
|
/* $OpenLDAP$ */
|
|
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
|
|
*
|
|
* Copyright 1998-2013 The OpenLDAP Foundation.
|
|
* Portions Copyright 1998-2003 Kurt D. Zeilenga.
|
|
* Portions Copyright 1995 IBM Corporation.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted only as authorized by the OpenLDAP
|
|
* Public License.
|
|
*
|
|
* A copy of this license is available in the file LICENSE in the
|
|
* top-level directory of the distribution or, alternatively, at
|
|
* <http://www.OpenLDAP.org/license.html>.
|
|
*/
|
|
/* Portions Copyright (c) 1996, 1998 by Internet Software Consortium.
|
|
*
|
|
* 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 INTERNET SOFTWARE CONSORTIUM DISCLAIMS
|
|
* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
|
|
* CONSORTIUM 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 work is based upon Base64 routines (developed by IBM) found
|
|
* Berkeley Internet Name Daemon (BIND) as distributed by ISC. They
|
|
* were adapted for inclusion in OpenLDAP Software by Kurt D. Zeilenga.
|
|
*/
|
|
|
|
#include "portable.h"
|
|
|
|
#include <ac/assert.h>
|
|
#include <ac/stdlib.h>
|
|
#include <ac/ctype.h>
|
|
#include <ac/string.h>
|
|
|
|
/* include socket.h to get sys/types.h and/or winsock2.h */
|
|
#include <ac/socket.h>
|
|
|
|
#include "lutil.h"
|
|
|
|
static const char Base64[] =
|
|
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
|
|
static const char Pad64 = '=';
|
|
|
|
/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
|
|
The following encoding technique is taken from RFC 1521 by Borenstein
|
|
and Freed. It is reproduced here in a slightly edited form for
|
|
convenience.
|
|
|
|
A 65-character subset of US-ASCII is used, enabling 6 bits to be
|
|
represented per printable character. (The extra 65th character, "=",
|
|
is used to signify a special processing function.)
|
|
|
|
The encoding process represents 24-bit groups of input bits as output
|
|
strings of 4 encoded characters. Proceeding from left to right, a
|
|
24-bit input group is formed by concatenating 3 8-bit input groups.
|
|
These 24 bits are then treated as 4 concatenated 6-bit groups, each
|
|
of which is translated into a single digit in the base64 alphabet.
|
|
|
|
Each 6-bit group is used as an index into an array of 64 printable
|
|
characters. The character referenced by the index is placed in the
|
|
output string.
|
|
|
|
Table 1: The Base64 Alphabet
|
|
|
|
Value Encoding Value Encoding Value Encoding Value Encoding
|
|
0 A 17 R 34 i 51 z
|
|
1 B 18 S 35 j 52 0
|
|
2 C 19 T 36 k 53 1
|
|
3 D 20 U 37 l 54 2
|
|
4 E 21 V 38 m 55 3
|
|
5 F 22 W 39 n 56 4
|
|
6 G 23 X 40 o 57 5
|
|
7 H 24 Y 41 p 58 6
|
|
8 I 25 Z 42 q 59 7
|
|
9 J 26 a 43 r 60 8
|
|
10 K 27 b 44 s 61 9
|
|
11 L 28 c 45 t 62 +
|
|
12 M 29 d 46 u 63 /
|
|
13 N 30 e 47 v
|
|
14 O 31 f 48 w (pad) =
|
|
15 P 32 g 49 x
|
|
16 Q 33 h 50 y
|
|
|
|
Special processing is performed if fewer than 24 bits are available
|
|
at the end of the data being encoded. A full encoding quantum is
|
|
always completed at the end of a quantity. When fewer than 24 input
|
|
bits are available in an input group, zero bits are added (on the
|
|
right) to form an integral number of 6-bit groups. Padding at the
|
|
end of the data is performed using the '=' character.
|
|
|
|
Since all base64 input is an integral number of octets, only the
|
|
-------------------------------------------------
|
|
following cases can arise:
|
|
|
|
(1) the final quantum of encoding input is an integral
|
|
multiple of 24 bits; here, the final unit of encoded
|
|
output will be an integral multiple of 4 characters
|
|
with no "=" padding,
|
|
(2) the final quantum of encoding input is exactly 8 bits;
|
|
here, the final unit of encoded output will be two
|
|
characters followed by two "=" padding characters, or
|
|
(3) the final quantum of encoding input is exactly 16 bits;
|
|
here, the final unit of encoded output will be three
|
|
characters followed by one "=" padding character.
|
|
*/
|
|
|
|
int
|
|
lutil_b64_ntop(
|
|
u_char const *src,
|
|
size_t srclength,
|
|
char *target,
|
|
size_t targsize)
|
|
{
|
|
size_t datalength = 0;
|
|
u_char input[3];
|
|
u_char output[4];
|
|
size_t i;
|
|
|
|
while (2 < srclength) {
|
|
input[0] = *src++;
|
|
input[1] = *src++;
|
|
input[2] = *src++;
|
|
srclength -= 3;
|
|
|
|
output[0] = input[0] >> 2;
|
|
output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
|
|
output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
|
|
output[3] = input[2] & 0x3f;
|
|
assert(output[0] < 64);
|
|
assert(output[1] < 64);
|
|
assert(output[2] < 64);
|
|
assert(output[3] < 64);
|
|
|
|
if (datalength + 4 > targsize)
|
|
return (-1);
|
|
target[datalength++] = Base64[output[0]];
|
|
target[datalength++] = Base64[output[1]];
|
|
target[datalength++] = Base64[output[2]];
|
|
target[datalength++] = Base64[output[3]];
|
|
}
|
|
|
|
/* Now we worry about padding. */
|
|
if (0 != srclength) {
|
|
/* Get what's left. */
|
|
input[0] = input[1] = input[2] = '\0';
|
|
for (i = 0; i < srclength; i++)
|
|
input[i] = *src++;
|
|
|
|
output[0] = input[0] >> 2;
|
|
output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
|
|
output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
|
|
assert(output[0] < 64);
|
|
assert(output[1] < 64);
|
|
assert(output[2] < 64);
|
|
|
|
if (datalength + 4 > targsize)
|
|
return (-1);
|
|
target[datalength++] = Base64[output[0]];
|
|
target[datalength++] = Base64[output[1]];
|
|
if (srclength == 1)
|
|
target[datalength++] = Pad64;
|
|
else
|
|
target[datalength++] = Base64[output[2]];
|
|
target[datalength++] = Pad64;
|
|
}
|
|
if (datalength >= targsize)
|
|
return (-1);
|
|
target[datalength] = '\0'; /* Returned value doesn't count \0. */
|
|
return (datalength);
|
|
}
|
|
|
|
/* skips all whitespace anywhere.
|
|
converts characters, four at a time, starting at (or after)
|
|
src from base - 64 numbers into three 8 bit bytes in the target area.
|
|
it returns the number of data bytes stored at the target, or -1 on error.
|
|
*/
|
|
|
|
int
|
|
lutil_b64_pton(
|
|
char const *src,
|
|
u_char *target,
|
|
size_t targsize)
|
|
{
|
|
int tarindex, state, ch;
|
|
char *pos;
|
|
|
|
state = 0;
|
|
tarindex = 0;
|
|
|
|
while ((ch = *src++) != '\0') {
|
|
if (isascii(ch) && isspace(ch)) /* Skip whitespace anywhere. */
|
|
continue;
|
|
|
|
if (ch == Pad64)
|
|
break;
|
|
|
|
pos = strchr(Base64, ch);
|
|
if (pos == 0) /* A non-base64 character. */
|
|
return (-1);
|
|
|
|
switch (state) {
|
|
case 0:
|
|
if (target) {
|
|
if ((size_t)tarindex >= targsize)
|
|
return (-1);
|
|
target[tarindex] = (pos - Base64) << 2;
|
|
}
|
|
state = 1;
|
|
break;
|
|
case 1:
|
|
if (target) {
|
|
if ((size_t)tarindex + 1 >= targsize)
|
|
return (-1);
|
|
target[tarindex] |= (pos - Base64) >> 4;
|
|
target[tarindex+1] = ((pos - Base64) & 0x0f)
|
|
<< 4 ;
|
|
}
|
|
tarindex++;
|
|
state = 2;
|
|
break;
|
|
case 2:
|
|
if (target) {
|
|
if ((size_t)tarindex + 1 >= targsize)
|
|
return (-1);
|
|
target[tarindex] |= (pos - Base64) >> 2;
|
|
target[tarindex+1] = ((pos - Base64) & 0x03)
|
|
<< 6;
|
|
}
|
|
tarindex++;
|
|
state = 3;
|
|
break;
|
|
case 3:
|
|
if (target) {
|
|
if ((size_t)tarindex >= targsize)
|
|
return (-1);
|
|
target[tarindex] |= (pos - Base64);
|
|
}
|
|
tarindex++;
|
|
state = 0;
|
|
break;
|
|
default:
|
|
abort();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We are done decoding Base-64 chars. Let's see if we ended
|
|
* on a byte boundary, and/or with erroneous trailing characters.
|
|
*/
|
|
|
|
if (ch == Pad64) { /* We got a pad char. */
|
|
ch = *src++; /* Skip it, get next. */
|
|
switch (state) {
|
|
case 0: /* Invalid = in first position */
|
|
case 1: /* Invalid = in second position */
|
|
return (-1);
|
|
|
|
case 2: /* Valid, means one byte of info */
|
|
/* Skip any number of spaces. */
|
|
for ((void)NULL; ch != '\0'; ch = *src++)
|
|
if (! (isascii(ch) && isspace(ch)))
|
|
break;
|
|
/* Make sure there is another trailing = sign. */
|
|
if (ch != Pad64)
|
|
return (-1);
|
|
ch = *src++; /* Skip the = */
|
|
/* Fall through to "single trailing =" case. */
|
|
/* FALLTHROUGH */
|
|
|
|
case 3: /* Valid, means two bytes of info */
|
|
/*
|
|
* We know this char is an =. Is there anything but
|
|
* whitespace after it?
|
|
*/
|
|
for ((void)NULL; ch != '\0'; ch = *src++)
|
|
if (! (isascii(ch) && isspace(ch)))
|
|
return (-1);
|
|
|
|
/*
|
|
* Now make sure for cases 2 and 3 that the "extra"
|
|
* bits that slopped past the last full byte were
|
|
* zeros. If we don't check them, they become a
|
|
* subliminal channel.
|
|
*/
|
|
if (target && target[tarindex] != 0)
|
|
return (-1);
|
|
}
|
|
} else {
|
|
/*
|
|
* We ended by seeing the end of the string. Make sure we
|
|
* have no partial bytes lying around.
|
|
*/
|
|
if (state != 0)
|
|
return (-1);
|
|
}
|
|
|
|
return (tarindex);
|
|
}
|