/src/libvncserver/src/common/base64.c

Source
/*  $OpenBSD: base64.c,v 1.8 2015/01/16 16:48:51 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 <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <arpa/nameser.h>

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

#include <stdlib.h>
#include <string.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
__b64_ntop(src, srclength, target, targsize)
  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;

    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);

    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(src, target, targsize)
  char const *src;
  u_char *target;
  size_t targsize;
{
  int tarindex, state, ch;
  u_char nextbyte;
  char *pos;

  state = 0;
  tarindex = 0;

  while ((ch = (unsigned char)*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 >= targsize)
          return (-1);
        target[tarindex]   |=  (pos - Base64) >> 4;
        nextbyte = ((pos - Base64) & 0x0f) << 4;
        if (tarindex + 1 < targsize)
          target[tarindex+1] = nextbyte;
        else if (nextbyte)
          return (-1);
      }
      tarindex++;
      state = 2;
      break;
    case 2:
      if (target) {
        if (tarindex >= targsize)
          return (-1);
        target[tarindex]   |=  (pos - Base64) >> 2;
        nextbyte = ((pos - Base64) & 0x03) << 6;
        if (tarindex + 1 < targsize)
          target[tarindex+1] = nextbyte;
        else if (nextbyte)
          return (-1);
      }
      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 = (unsigned char)*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 = (unsigned char)*src++)
        if (!isspace(ch))
          break;
      /* Make sure there is another trailing = sign. */
      if (ch != Pad64)
        return (-1);
      ch = (unsigned char)*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 = (unsigned char)*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 && tarindex < targsize &&
          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);
}

Coverage Report

Created: 2025-10-10 06:07

Line	Count	Source
1		/* $OpenBSD: base64.c,v 1.8 2015/01/16 16:48:51 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 <sys/types.h>
46		#include <sys/socket.h>
47		#include <netinet/in.h>
48		#include <arpa/inet.h>
49		#include <arpa/nameser.h>
50
51		#include <ctype.h>
52		#include <resolv.h>
53		#include <stdio.h>
54
55		#include <stdlib.h>
56		#include <string.h>
57
58		static const char Base64[] =
59		"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
60		static const char Pad64 = '=';
61
62		/* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
63		The following encoding technique is taken from RFC 1521 by Borenstein
64		and Freed. It is reproduced here in a slightly edited form for
65		convenience.
66
67		A 65-character subset of US-ASCII is used, enabling 6 bits to be
68		represented per printable character. (The extra 65th character, "=",
69		is used to signify a special processing function.)
70
71		The encoding process represents 24-bit groups of input bits as output
72		strings of 4 encoded characters. Proceeding from left to right, a
73		24-bit input group is formed by concatenating 3 8-bit input groups.
74		These 24 bits are then treated as 4 concatenated 6-bit groups, each
75		of which is translated into a single digit in the base64 alphabet.
76
77		Each 6-bit group is used as an index into an array of 64 printable
78		characters. The character referenced by the index is placed in the
79		output string.
80
81		Table 1: The Base64 Alphabet
82
83		Value Encoding Value Encoding Value Encoding Value Encoding
84		0 A 17 R 34 i 51 z
85		1 B 18 S 35 j 52 0
86		2 C 19 T 36 k 53 1
87		3 D 20 U 37 l 54 2
88		4 E 21 V 38 m 55 3
89		5 F 22 W 39 n 56 4
90		6 G 23 X 40 o 57 5
91		7 H 24 Y 41 p 58 6
92		8 I 25 Z 42 q 59 7
93		9 J 26 a 43 r 60 8
94		10 K 27 b 44 s 61 9
95		11 L 28 c 45 t 62 +
96		12 M 29 d 46 u 63 /
97		13 N 30 e 47 v
98		14 O 31 f 48 w (pad) =
99		15 P 32 g 49 x
100		16 Q 33 h 50 y
101
102		Special processing is performed if fewer than 24 bits are available
103		at the end of the data being encoded. A full encoding quantum is
104		always completed at the end of a quantity. When fewer than 24 input
105		bits are available in an input group, zero bits are added (on the
106		right) to form an integral number of 6-bit groups. Padding at the
107		end of the data is performed using the '=' character.
108
109		Since all base64 input is an integral number of octets, only the
110		-------------------------------------------------
111		following cases can arise:
112
113		(1) the final quantum of encoding input is an integral
114		multiple of 24 bits; here, the final unit of encoded
115		output will be an integral multiple of 4 characters
116		with no "=" padding,
117		(2) the final quantum of encoding input is exactly 8 bits;
118		here, the final unit of encoded output will be two
119		characters followed by two "=" padding characters, or
120		(3) the final quantum of encoding input is exactly 16 bits;
121		here, the final unit of encoded output will be three
122		characters followed by one "=" padding character.
123		*/
124
125		int
126		__b64_ntop(src, srclength, target, targsize)
127		u_char const *src;
128		size_t srclength;
129		char *target;
130		size_t targsize;
131	0	{
132	0	size_t datalength = 0;
133	0	u_char input[3];
134	0	u_char output[4];
135	0	int i;
136
137	0	while (2 < srclength) {
138	0	input[0] = *src++;
139	0	input[1] = *src++;
140	0	input[2] = *src++;
141	0	srclength -= 3;
142
143	0	output[0] = input[0] >> 2;
144	0	output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
145	0	output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
146	0	output[3] = input[2] & 0x3f;
147
148	0	if (datalength + 4 > targsize)
149	0	return (-1);
150	0	target[datalength++] = Base64[output[0]];
151	0	target[datalength++] = Base64[output[1]];
152	0	target[datalength++] = Base64[output[2]];
153	0	target[datalength++] = Base64[output[3]];
154	0	}
155
156		/* Now we worry about padding. */
157	0	if (0 != srclength) {
158		/* Get what's left. */
159	0	input[0] = input[1] = input[2] = '\0';
160	0	for (i = 0; i < srclength; i++)
161	0	input[i] = *src++;
162
163	0	output[0] = input[0] >> 2;
164	0	output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
165	0	output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
166
167	0	if (datalength + 4 > targsize)
168	0	return (-1);
169	0	target[datalength++] = Base64[output[0]];
170	0	target[datalength++] = Base64[output[1]];
171	0	if (srclength == 1)
172	0	target[datalength++] = Pad64;
173	0	else
174	0	target[datalength++] = Base64[output[2]];
175	0	target[datalength++] = Pad64;
176	0	}
177	0	if (datalength >= targsize)
178	0	return (-1);
179	0	target[datalength] = '\0'; /* Returned value doesn't count \0. */
180	0	return (datalength);
181	0	}
182
183		/* skips all whitespace anywhere.
184		converts characters, four at a time, starting at (or after)
185		src from base - 64 numbers into three 8 bit bytes in the target area.
186		it returns the number of data bytes stored at the target, or -1 on error.
187		*/
188
189		int
190		__b64_pton(src, target, targsize)
191		char const *src;
192		u_char *target;
193		size_t targsize;
194	0	{
195	0	int tarindex, state, ch;
196	0	u_char nextbyte;
197	0	char *pos;
198
199	0	state = 0;
200	0	tarindex = 0;
201
202	0	while ((ch = (unsigned char)*src++) != '\0') {
203	0	if (isspace(ch)) /* Skip whitespace anywhere. */
204	0	continue;
205
206	0	if (ch == Pad64)
207	0	break;
208
209	0	pos = strchr(Base64, ch);
210	0	if (pos == 0) /* A non-base64 character. */
211	0	return (-1);
212
213	0	switch (state) {
214	0	case 0:
215	0	if (target) {
216	0	if (tarindex >= targsize)
217	0	return (-1);
218	0	target[tarindex] = (pos - Base64) << 2;
219	0	}
220	0	state = 1;
221	0	break;
222	0	case 1:
223	0	if (target) {
224	0	if (tarindex >= targsize)
225	0	return (-1);
226	0	target[tarindex] \|= (pos - Base64) >> 4;
227	0	nextbyte = ((pos - Base64) & 0x0f) << 4;
228	0	if (tarindex + 1 < targsize)
229	0	target[tarindex+1] = nextbyte;
230	0	else if (nextbyte)
231	0	return (-1);
232	0	}
233	0	tarindex++;
234	0	state = 2;
235	0	break;
236	0	case 2:
237	0	if (target) {
238	0	if (tarindex >= targsize)
239	0	return (-1);
240	0	target[tarindex] \|= (pos - Base64) >> 2;
241	0	nextbyte = ((pos - Base64) & 0x03) << 6;
242	0	if (tarindex + 1 < targsize)
243	0	target[tarindex+1] = nextbyte;
244	0	else if (nextbyte)
245	0	return (-1);
246	0	}
247	0	tarindex++;
248	0	state = 3;
249	0	break;
250	0	case 3:
251	0	if (target) {
252	0	if (tarindex >= targsize)
253	0	return (-1);
254	0	target[tarindex] \|= (pos - Base64);
255	0	}
256	0	tarindex++;
257	0	state = 0;
258	0	break;
259	0	}
260	0	}
261
262		/*
263		* We are done decoding Base-64 chars. Let's see if we ended
264		* on a byte boundary, and/or with erroneous trailing characters.
265		*/
266
267	0	if (ch == Pad64) { /* We got a pad char. */
268	0	ch = (unsigned char)src++; / Skip it, get next. */
269	0	switch (state) {
270	0	case 0: /* Invalid = in first position */
271	0	case 1: /* Invalid = in second position */
272	0	return (-1);
273
274	0	case 2: /* Valid, means one byte of info */
275		/* Skip any number of spaces. */
276	0	for (; ch != '\0'; ch = (unsigned char)*src++)
277	0	if (!isspace(ch))
278	0	break;
279		/* Make sure there is another trailing = sign. */
280	0	if (ch != Pad64)
281	0	return (-1);
282	0	ch = (unsigned char)src++; / Skip the = */
283		/* Fall through to "single trailing =" case. */
284		/* FALLTHROUGH */
285
286	0	case 3: /* Valid, means two bytes of info */
287		/*
288		* We know this char is an =. Is there anything but
289		* whitespace after it?
290		*/
291	0	for (; ch != '\0'; ch = (unsigned char)*src++)
292	0	if (!isspace(ch))
293	0	return (-1);
294
295		/*
296		* Now make sure for cases 2 and 3 that the "extra"
297		* bits that slopped past the last full byte were
298		* zeros. If we don't check them, they become a
299		* subliminal channel.
300		*/
301	0	if (target && tarindex < targsize &&
302	0	target[tarindex] != 0)
303	0	return (-1);
304	0	}
305	0	} else {
306		/*
307		* We ended by seeing the end of the string. Make sure we
308		* have no partial bytes lying around.
309		*/
310	0	if (state != 0)
311	0	return (-1);
312	0	}
313
314	0	return (tarindex);
315	0	}