lede-packages-rs

b64_pton.c (11434B)

---

 /*
  * 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.
  */
 
 /*
  * 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>
 
 #include <sys/types.h>
 #include <sys/param.h>
 #include <sys/socket.h>
 
 #include <netinet/in.h>
 #include <arpa/inet.h>
 
 #include <ctype.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 
 #include "fdm.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.
    */
 
 /* 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.
  */
 
 static int b64rmap_initialized = 0;
 static uint8_t b64rmap[256];
 
 static const uint8_t b64rmap_special = 0xf0;
 static const uint8_t b64rmap_end = 0xfd;
 static const uint8_t b64rmap_space = 0xfe;
 static const uint8_t b64rmap_invalid = 0xff;
 
 /**
  * Initializing the reverse map is not thread safe.
  * Which is fine for NSD. For now...
  **/
 static void
 b64_initialize_rmap ()
 {
 	int i;
 	char ch;
 
 	/* Null: end of string, stop parsing */
 	b64rmap[0] = b64rmap_end;
 
 	for (i = 1; i < 256; ++i) {
 		ch = (char)i;
 		/* Whitespaces */
 		if (isspace(ch))
 			b64rmap[i] = b64rmap_space;
 		/* Padding: stop parsing */
 		else if (ch == Pad64)
 			b64rmap[i] = b64rmap_end;
 		/* Non-base64 char */
 		else
 			b64rmap[i] = b64rmap_invalid;
 	}
 
 	/* Fill reverse mapping for base64 chars */
 	for (i = 0; Base64[i] != '\0'; ++i)
 		b64rmap[(uint8_t)Base64[i]] = i;
 
 	b64rmap_initialized = 1;
 }
 
 static int
 b64_pton_do(char const *src, uint8_t *target, size_t targsize)
 {
 	int tarindex, state, ch;
 	uint8_t ofs;
 
 	state = 0;
 	tarindex = 0;
 
 	while (1)
 	{
 		ch = *src++;
 		ofs = b64rmap[ch];
 
 		if (ofs >= b64rmap_special) {
 			/* Ignore whitespaces */
 			if (ofs == b64rmap_space)
 				continue;
 			/* End of base64 characters */
 			if (ofs == b64rmap_end)
 				break;
 			/* A non-base64 character. */
 			return (-1);
 		}
 
 		switch (state) {
 		case 0:
 			if ((size_t)tarindex >= targsize)
 				return (-1);
 			target[tarindex] = ofs << 2;
 			state = 1;
 			break;
 		case 1:
 			if ((size_t)tarindex + 1 >= targsize)
 				return (-1);
 			target[tarindex]   |=  ofs >> 4;
 			target[tarindex+1]  = (ofs & 0x0f)
 						<< 4 ;
 			tarindex++;
 			state = 2;
 			break;
 		case 2:
 			if ((size_t)tarindex + 1 >= targsize)
 				return (-1);
 			target[tarindex]   |=  ofs >> 2;
 			target[tarindex+1]  = (ofs & 0x03)
 						<< 6;
 			tarindex++;
 			state = 3;
 			break;
 		case 3:
 			if ((size_t)tarindex >= targsize)
 				return (-1);
 			target[tarindex] |= ofs;
 			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 (b64rmap[ch] != b64rmap_space)
 					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 (b64rmap[ch] != b64rmap_space)
 					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] != 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);
 }
 
 
 static int
 b64_pton_len(char const *src)
 {
 	int tarindex, state, ch;
 	uint8_t ofs;
 
 	state = 0;
 	tarindex = 0;
 
 	while (1)
 	{
 		ch = *src++;
 		ofs = b64rmap[ch];
 
 		if (ofs >= b64rmap_special) {
 			/* Ignore whitespaces */
 			if (ofs == b64rmap_space)
 				continue;
 			/* End of base64 characters */
 			if (ofs == b64rmap_end)
 				break;
 			/* A non-base64 character. */
 			return (-1);
 		}
 
 		switch (state) {
 		case 0:
 			state = 1;
 			break;
 		case 1:
 			tarindex++;
 			state = 2;
 			break;
 		case 2:
 			tarindex++;
 			state = 3;
 			break;
 		case 3:
 			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 (b64rmap[ch] != b64rmap_space)
 					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 (b64rmap[ch] != b64rmap_space)
 					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);
 }
 
 
 int
 local_b64_pton(char const *src, uint8_t *target, size_t targsize)
 {
 	if (!b64rmap_initialized)
 		b64_initialize_rmap ();
 
 	if (target)
 		return b64_pton_do (src, target, targsize);
 	else
 		return b64_pton_len (src);
 }