[openssh.git] / bsd-base64.c

/*	$OpenBSD: base64.c,v 1.3 1997/11/08 20:46:55 deraadt Exp $	*/

/*
 * Copyright (c) 1996 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.
 */

/*
 * Portions Copyright (c) 1995 by International Business Machines, Inc.
 *
 * International Business Machines, Inc. (hereinafter called IBM) grants
 * permission under its copyrights to use, copy, modify, and distribute this
 * Software with or without fee, provided that the above copyright notice and
 * all paragraphs of this notice appear in all copies, and that the name of IBM
 * not be used in connection with the marketing of any product incorporating
 * the Software or modifications thereof, without specific, written prior
 * permission.
 *
 * To the extent it has a right to do so, IBM grants an immunity from suit
 * under its patents, if any, for the use, sale or manufacture of products to
 * the extent that such products are used for performing Domain Name System
 * dynamic updates in TCP/IP networks by means of the Software.  No immunity is
 * granted for any product per se or for any other function of any product.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE.  IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
 * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
 * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
 * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
 */

#include "config.h"

#ifndef HAVE_B64_NTOP

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#include <ctype.h>
#include <resolv.h>
#include <stdio.h>

#include <stdlib.h>
#include <string.h>

#define Assert(Cond) if (!(Cond)) abort()

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
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];
	int 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
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 (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 (tarindex >= targsize)
					return (-1);
				target[tarindex] = (pos - Base64) << 2;
			}
			state = 1;
			break;
		case 1:
			if (target) {
				if (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 (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 (tarindex >= targsize)
					return (-1);
				target[tarindex] |= (pos - Base64);
			}
			tarindex++;
			state = 0;
			break;
		}
	}

	/*
	 * 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 (; ch != '\0'; ch = *src++)
				if (!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 (; ch != '\0'; ch = *src++)
				if (!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);
}

#endif /* HAVE_B64_NTOP */
Commit	Line	Data
1d1ffb87	1	/* $OpenBSD: base64.c,v 1.3 1997/11/08 20:46:55 deraadt Exp $ */
	2
	3	/*
	4	* Copyright (c) 1996 by Internet Software Consortium.
	5	*
	6	* Permission to use, copy, modify, and distribute this software for any
	7	* purpose with or without fee is hereby granted, provided that the above
	8	* copyright notice and this permission notice appear in all copies.
	9	*
	10	* THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
	11	* ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
	12	* OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
	13	* CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
	14	* DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
	15	* PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
	16	* ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
	17	* SOFTWARE.
	18	*/
	19
	20	/*
	21	* Portions Copyright (c) 1995 by International Business Machines, Inc.
	22	*
	23	* International Business Machines, Inc. (hereinafter called IBM) grants
	24	* permission under its copyrights to use, copy, modify, and distribute this
	25	* Software with or without fee, provided that the above copyright notice and
	26	* all paragraphs of this notice appear in all copies, and that the name of IBM
	27	* not be used in connection with the marketing of any product incorporating
	28	* the Software or modifications thereof, without specific, written prior
	29	* permission.
	30	*
	31	* To the extent it has a right to do so, IBM grants an immunity from suit
	32	* under its patents, if any, for the use, sale or manufacture of products to
	33	* the extent that such products are used for performing Domain Name System
	34	* dynamic updates in TCP/IP networks by means of the Software. No immunity is
	35	* granted for any product per se or for any other function of any product.
	36	*
	37	* THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
	38	* INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
	39	* PARTICULAR PURPOSE. IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
	40	* DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
	41	* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
	42	* IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
	43	*/
	44
	45	#include "config.h"
	46
	47	#ifndef HAVE_B64_NTOP
	48
	49	#include <sys/types.h>
	50	#include <sys/param.h>
	51	#include <sys/socket.h>
	52	#include <netinet/in.h>
	53	#include <arpa/inet.h>
	54
	55	#include <ctype.h>
	56	#include <resolv.h>
	57	#include <stdio.h>
	58
	59	#include <stdlib.h>
	60	#include <string.h>
	61
	62	#define Assert(Cond) if (!(Cond)) abort()
	63
	64	static const char Base64[] =
65	"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
66	static const char Pad64 = '=';
67
68	/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
69	The following encoding technique is taken from RFC 1521 by Borenstein
70	and Freed. It is reproduced here in a slightly edited form for
71	convenience.
72
73	A 65-character subset of US-ASCII is used, enabling 6 bits to be
74	represented per printable character. (The extra 65th character, "=",
75	is used to signify a special processing function.)
76
77	The encoding process represents 24-bit groups of input bits as output
78	strings of 4 encoded characters. Proceeding from left to right, a
79	24-bit input group is formed by concatenating 3 8-bit input groups.
80	These 24 bits are then treated as 4 concatenated 6-bit groups, each
81	of which is translated into a single digit in the base64 alphabet.
82
83	Each 6-bit group is used as an index into an array of 64 printable
84	characters. The character referenced by the index is placed in the
85	output string.
86
87	Table 1: The Base64 Alphabet
88
89	Value Encoding Value Encoding Value Encoding Value Encoding
90	0 A 17 R 34 i 51 z
91	1 B 18 S 35 j 52 0
92	2 C 19 T 36 k 53 1
93	3 D 20 U 37 l 54 2
94	4 E 21 V 38 m 55 3
95	5 F 22 W 39 n 56 4
96	6 G 23 X 40 o 57 5
97	7 H 24 Y 41 p 58 6
98	8 I 25 Z 42 q 59 7
99	9 J 26 a 43 r 60 8
100	10 K 27 b 44 s 61 9
101	11 L 28 c 45 t 62 +
102	12 M 29 d 46 u 63 /
103	13 N 30 e 47 v
104	14 O 31 f 48 w (pad) =
105	15 P 32 g 49 x
106	16 Q 33 h 50 y
107
108	Special processing is performed if fewer than 24 bits are available
109	at the end of the data being encoded. A full encoding quantum is
110	always completed at the end of a quantity. When fewer than 24 input
111	bits are available in an input group, zero bits are added (on the
112	right) to form an integral number of 6-bit groups. Padding at the
113	end of the data is performed using the '=' character.
114
115	Since all base64 input is an integral number of octets, only the
116	-------------------------------------------------
117	following cases can arise:
118
119	(1) the final quantum of encoding input is an integral
120	multiple of 24 bits; here, the final unit of encoded
121	output will be an integral multiple of 4 characters
122	with no "=" padding,
123	(2) the final quantum of encoding input is exactly 8 bits;
124	here, the final unit of encoded output will be two
125	characters followed by two "=" padding characters, or
126	(3) the final quantum of encoding input is exactly 16 bits;
127	here, the final unit of encoded output will be three
128	characters followed by one "=" padding character.
129	*/
130
131	int
132	b64_ntop(u_char const src, size_t srclength, char target, size_t targsize)
133	{
134	size_t datalength = 0;
135	u_char input[3];
136	u_char output[4];
137	int i;
138
139	while (2 < srclength) {
140	input[0] = *src++;
141	input[1] = *src++;
142	input[2] = *src++;
143	srclength -= 3;
144
145	output[0] = input[0] >> 2;
146	output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
147	output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
148	output[3] = input[2] & 0x3f;
149	Assert(output[0] < 64);
150	Assert(output[1] < 64);
151	Assert(output[2] < 64);
152	Assert(output[3] < 64);
153
154	if (datalength + 4 > targsize)
155	return (-1);
156	target[datalength++] = Base64[output[0]];
157	target[datalength++] = Base64[output[1]];
158	target[datalength++] = Base64[output[2]];
159	target[datalength++] = Base64[output[3]];
160	}
161
162	/* Now we worry about padding. */
163	if (0 != srclength) {
164	/* Get what's left. */
165	input[0] = input[1] = input[2] = '\0';
166	for (i = 0; i < srclength; i++)
167	input[i] = *src++;
168
169	output[0] = input[0] >> 2;
170	output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
171	output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
172	Assert(output[0] < 64);
173	Assert(output[1] < 64);
174	Assert(output[2] < 64);
175
176	if (datalength + 4 > targsize)
177	return (-1);
178	target[datalength++] = Base64[output[0]];
179	target[datalength++] = Base64[output[1]];
180	if (srclength == 1)
181	target[datalength++] = Pad64;
182	else
183	target[datalength++] = Base64[output[2]];
184	target[datalength++] = Pad64;
185	}
186	if (datalength >= targsize)
187	return (-1);
188	target[datalength] = '\0'; /* Returned value doesn't count \0. */
189	return (datalength);
190	}
191
192	/* skips all whitespace anywhere.
193	converts characters, four at a time, starting at (or after)
194	src from base - 64 numbers into three 8 bit bytes in the target area.
195	it returns the number of data bytes stored at the target, or -1 on error.
196	*/
197
198	int
199	b64_pton(char const src, u_char target, size_t targsize)
200	{
201	int tarindex, state, ch;
202	char *pos;
203
204	state = 0;
205	tarindex = 0;
206
207	while ((ch = *src++) != '\0') {
208	if (isspace(ch)) /* Skip whitespace anywhere. */
209	continue;
210
211	if (ch == Pad64)
212	break;
213
214	pos = strchr(Base64, ch);
215	if (pos == 0) /* A non-base64 character. */
216	return (-1);
217
218	switch (state) {
219	case 0:
220	if (target) {
221	if (tarindex >= targsize)
222	return (-1);
223	target[tarindex] = (pos - Base64) << 2;
224	}
225	state = 1;
226	break;
227	case 1:
228	if (target) {
229	if (tarindex + 1 >= targsize)
230	return (-1);
231	target[tarindex] \|= (pos - Base64) >> 4;
232	target[tarindex+1] = ((pos - Base64) & 0x0f)
233	<< 4 ;
234	}
235	tarindex++;
236	state = 2;
237	break;
238	case 2:
239	if (target) {
240	if (tarindex + 1 >= targsize)
241	return (-1);
242	target[tarindex] \|= (pos - Base64) >> 2;
243	target[tarindex+1] = ((pos - Base64) & 0x03)
244	<< 6;
245	}
246	tarindex++;
247	state = 3;
248	break;
249	case 3:
250	if (target) {
251	if (tarindex >= targsize)
252	return (-1);
253	target[tarindex] \|= (pos - Base64);
254	}
255	tarindex++;
256	state = 0;
257	break;
258	}
259	}
260
261	/*
262	* We are done decoding Base-64 chars. Let's see if we ended
263	* on a byte boundary, and/or with erroneous trailing characters.
264	*/
265
266	if (ch == Pad64) { /* We got a pad char. */
267	ch = src++; / Skip it, get next. */
268	switch (state) {
269	case 0: /* Invalid = in first position */
270	case 1: /* Invalid = in second position */
271	return (-1);
272
273	case 2: /* Valid, means one byte of info */
274	/* Skip any number of spaces. */
275	for (; ch != '\0'; ch = *src++)
276	if (!isspace(ch))
277	break;
278	/* Make sure there is another trailing = sign. */
279	if (ch != Pad64)
280	return (-1);
281	ch = src++; / Skip the = */
282	/* Fall through to "single trailing =" case. */
283	/* FALLTHROUGH */
284
285	case 3: /* Valid, means two bytes of info */
286	/*
287	* We know this char is an =. Is there anything but
288	* whitespace after it?
289	*/
290	for (; ch != '\0'; ch = *src++)
291	if (!isspace(ch))
292	return (-1);
293
294	/*
295	* Now make sure for cases 2 and 3 that the "extra"
296	* bits that slopped past the last full byte were
297	* zeros. If we don't check them, they become a
298	* subliminal channel.
299	*/
300	if (target && target[tarindex] != 0)
301	return (-1);
302	}
303	} else {
304	/*
305	* We ended by seeing the end of the string. Make sure we
306	* have no partial bytes lying around.
307	*/
308	if (state != 0)
309	return (-1);
310	}
311
312	return (tarindex);
313	}
314
315	#endif /* HAVE_B64_NTOP */