StdLib/BsdSocketLib/base64.c

   1 /*
   2  * Copyright (c) 1996, 1998 by Internet Software Consortium.
   3  *
   4  * Permission to use, copy, modify, and distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice appear in all copies.
   7  *
   8  * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
   9  * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
  10  * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
  11  * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
  12  * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  13  * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  14  * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  15  * SOFTWARE.
  16  */
  17
  18 /*
  19  * Portions Copyright (c) 1995 by International Business Machines, Inc.
  20  *
  21  * International Business Machines, Inc. (hereinafter called IBM) grants
  22  * permission under its copyrights to use, copy, modify, and distribute this
  23  * Software with or without fee, provided that the above copyright notice and
  24  * all paragraphs of this notice appear in all copies, and that the name of IBM
  25  * not be used in connection with the marketing of any product incorporating
  26  * the Software or modifications thereof, without specific, written prior
  27  * permission.
  28  *
  29  * To the extent it has a right to do so, IBM grants an immunity from suit
  30  * under its patents, if any, for the use, sale or manufacture of products to
  31  * the extent that such products are used for performing Domain Name System
  32  * dynamic updates in TCP/IP networks by means of the Software.  No immunity is
  33  * granted for any product per se or for any other function of any product.
  34  *
  35  * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
  36  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  37  * PARTICULAR PURPOSE.  IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
  38  * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
  39  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
  40  * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
  41  */
  42
  43 /*
  44  * Portions copyright (c) 1999, 2000
  45  * Intel Corporation.
  46  * All rights reserved.
  47  *
  48  * Redistribution and use in source and binary forms, with or without
  49  * modification, are permitted provided that the following conditions
  50  * are met:
  51  *
  52  * 1. Redistributions of source code must retain the above copyright
  53  *    notice, this list of conditions and the following disclaimer.
  54  *
  55  * 2. Redistributions in binary form must reproduce the above copyright
  56  *    notice, this list of conditions and the following disclaimer in the
  57  *    documentation and/or other materials provided with the distribution.
  58  *
  59  * 3. All advertising materials mentioning features or use of this software
  60  *    must display the following acknowledgement:
  61  *
  62  *    This product includes software developed by Intel Corporation and
  63  *    its contributors.
  64  *
  65  * 4. Neither the name of Intel Corporation or its contributors may be
  66  *    used to endorse or promote products derived from this software
  67  *    without specific prior written permission.
  68  *
  69  * THIS SOFTWARE IS PROVIDED BY INTEL CORPORATION AND CONTRIBUTORS ``AS IS''
  70  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  71  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  72  * ARE DISCLAIMED.  IN NO EVENT SHALL INTEL CORPORATION OR CONTRIBUTORS BE
  73  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  74  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  75  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  76  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  77  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  78  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  79  * THE POSSIBILITY OF SUCH DAMAGE.
  80  *
  81   base64.c,v 1.1.1.1 2003/11/19 01:51:25 kyu3 Exp
  82  */
  83
  84 #include <sys/types.h>
  85 #include <sys/param.h>
  86 #include <sys/socket.h>
  87
  88 #include <netinet/in.h>
  89 #include <arpa/inet.h>
  90 #include <arpa/nameser.h>
  91
  92 #include <ctype.h>
  93 #include <resolv.h>
  94 #include <stdio.h>
  95 #include <stdlib.h>
  96 #include <string.h>
  97
  98 #define Assert(Cond) if (!(Cond)) abort()
  99
 100 static const char Base64[] =
 101   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 102 static const char Pad64 = '=';
 103
 104 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
 105    The following encoding technique is taken from RFC 1521 by Borenstein
 106    and Freed.  It is reproduced here in a slightly edited form for
 107    convenience.
 108
 109    A 65-character subset of US-ASCII is used, enabling 6 bits to be
 110    represented per printable character. (The extra 65th character, "=",
 111    is used to signify a special processing function.)
 112
 113    The encoding process represents 24-bit groups of input bits as output
 114    strings of 4 encoded characters. Proceeding from left to right, a
 115    24-bit input group is formed by concatenating 3 8-bit input groups.
 116    These 24 bits are then treated as 4 concatenated 6-bit groups, each
 117    of which is translated into a single digit in the base64 alphabet.
 118
 119    Each 6-bit group is used as an index into an array of 64 printable
 120    characters. The character referenced by the index is placed in the
 121    output string.
 122
 123                          Table 1: The Base64 Alphabet
 124
 125       Value Encoding  Value Encoding  Value Encoding  Value Encoding
 126           0 A            17 R            34 i            51 z
 127           1 B            18 S            35 j            52 0
 128           2 C            19 T            36 k            53 1
 129           3 D            20 U            37 l            54 2
 130           4 E            21 V            38 m            55 3
 131           5 F            22 W            39 n            56 4
 132           6 G            23 X            40 o            57 5
 133           7 H            24 Y            41 p            58 6
 134           8 I            25 Z            42 q            59 7
 135           9 J            26 a            43 r            60 8
 136          10 K            27 b            44 s            61 9
 137          11 L            28 c            45 t            62 +
 138          12 M            29 d            46 u            63 /
 139          13 N            30 e            47 v
 140          14 O            31 f            48 w         (pad) =
 141          15 P            32 g            49 x
 142          16 Q            33 h            50 y
 143
 144    Special processing is performed if fewer than 24 bits are available
 145    at the end of the data being encoded.  A full encoding quantum is
 146    always completed at the end of a quantity.  When fewer than 24 input
 147    bits are available in an input group, zero bits are added (on the
 148    right) to form an integral number of 6-bit groups.  Padding at the
 149    end of the data is performed using the '=' character.
 150
 151    Since all base64 input is an integral number of octets, only the
 152          -------------------------------------------------
 153    following cases can arise:
 154
 155        (1) the final quantum of encoding input is an integral
 156            multiple of 24 bits; here, the final unit of encoded
 157      output will be an integral multiple of 4 characters
 158      with no "=" padding,
 159        (2) the final quantum of encoding input is exactly 8 bits;
 160            here, the final unit of encoded output will be two
 161      characters followed by two "=" padding characters, or
 162        (3) the final quantum of encoding input is exactly 16 bits;
 163            here, the final unit of encoded output will be three
 164      characters followed by one "=" padding character.
 165    */
 166
 167 int
 168 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) {
 169   size_t datalength = 0;
 170   u_char input[3];
 171   u_char output[4];
 172   size_t i;
 173
 174   while (2 < srclength) {
 175     input[0] = *src++;
 176     input[1] = *src++;
 177     input[2] = *src++;
 178     srclength -= 3;
 179
 180     output[0] = input[0] >> 2;
 181     output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
 182     output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
 183     output[3] = input[2] & 0x3f;
 184     Assert(output[0] < 64);
 185     Assert(output[1] < 64);
 186     Assert(output[2] < 64);
 187     Assert(output[3] < 64);
 188
 189     if (datalength + 4 > targsize)
 190       return (-1);
 191     target[datalength++] = Base64[output[0]];
 192     target[datalength++] = Base64[output[1]];
 193     target[datalength++] = Base64[output[2]];
 194     target[datalength++] = Base64[output[3]];
 195   }
 196
 197   /* Now we worry about padding. */
 198   if (0 != srclength) {
 199     /* Get what's left. */
 200     input[0] = input[1] = input[2] = '\0';
 201     for (i = 0; i < srclength; i++)
 202       input[i] = *src++;
 203
 204     output[0] = input[0] >> 2;
 205     output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
 206     output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
 207     Assert(output[0] < 64);
 208     Assert(output[1] < 64);
 209     Assert(output[2] < 64);
 210
 211     if (datalength + 4 > targsize)
 212       return (-1);
 213     target[datalength++] = Base64[output[0]];
 214     target[datalength++] = Base64[output[1]];
 215     if (srclength == 1)
 216       target[datalength++] = Pad64;
 217     else
 218       target[datalength++] = Base64[output[2]];
 219     target[datalength++] = Pad64;
 220   }
 221   if (datalength >= targsize)
 222     return (-1);
 223   target[datalength] = '\0';  /* Returned value doesn't count \0. */
 224   return ((int)datalength);
 225 }
 226
 227 /* skips all whitespace anywhere.
 228    converts characters, four at a time, starting at (or after)
 229    src from base - 64 numbers into three 8 bit bytes in the target area.
 230    it returns the number of data bytes stored at the target, or -1 on error.
 231  */
 232
 233 int
 234 b64_pton(
 235   char const *src,
 236   u_char *target,
 237   size_t targsize
 238   )
 239 {
 240   int tarindex, state, ch;
 241   char *pos;
 242
 243   state = 0;
 244   tarindex = 0;
 245
 246   while ((ch = *src++) != '\0') {
 247     if (isspace(ch))  /* Skip whitespace anywhere. */
 248       continue;
 249
 250     if (ch == Pad64)
 251       break;
 252
 253     pos = strchr(Base64, ch);
 254     if (pos == 0)     /* A non-base64 character. */
 255       return (-1);
 256
 257     switch (state) {
 258     case 0:
 259       if (target) {
 260         if ((size_t)tarindex >= targsize)
 261           return (-1);
 262         target[tarindex] = (u_char)((pos - Base64) << 2);
 263       }
 264       state = 1;
 265       break;
 266     case 1:
 267       if (target) {
 268         if ((size_t)tarindex + 1 >= targsize)
 269           return (-1);
 270         target[tarindex]   |= (u_char)((pos - Base64) >> 4);
 271         target[tarindex+1]  = (u_char)(((pos - Base64) & 0x0f)
 272               << 4) ;
 273       }
 274       tarindex++;
 275       state = 2;
 276       break;
 277     case 2:
 278       if (target) {
 279         if ((size_t)tarindex + 1 >= targsize)
 280           return (-1);
 281         target[tarindex]   |= (u_char)((pos - Base64) >> 2);
 282         target[tarindex+1]  = (u_char)(((pos - Base64) & 0x03)
 283               << 6);
 284       }
 285       tarindex++;
 286       state = 3;
 287       break;
 288     case 3:
 289       if (target) {
 290         if ((size_t)tarindex >= targsize)
 291           return (-1);
 292         target[tarindex] |= (u_char)(pos - Base64);
 293       }
 294       tarindex++;
 295       state = 0;
 296       break;
 297     default:
 298       abort();
 299     }
 300   }
 301
 302   /*
 303    * We are done decoding Base-64 chars.  Let's see if we ended
 304    * on a byte boundary, and/or with erroneous trailing characters.
 305    */
 306
 307   if (ch == Pad64) {    /* We got a pad char. */
 308     ch = *src++;    /* Skip it, get next. */
 309     switch (state) {
 310     case 0:   /* Invalid = in first position */
 311     case 1:   /* Invalid = in second position */
 312       return (-1);
 313
 314     case 2:   /* Valid, means one byte of info */
 315       /* Skip any number of spaces. */
 316       for ((void)NULL; ch != '\0'; ch = *src++)
 317         if (!isspace(ch))
 318           break;
 319       /* Make sure there is another trailing = sign. */
 320       if (ch != Pad64)
 321         return (-1);
 322       ch = *src++;    /* Skip the = */
 323       /* Fall through to "single trailing =" case. */
 324       /* FALLTHROUGH */
 325
 326     case 3:   /* Valid, means two bytes of info */
 327       /*
 328        * We know this char is an =.  Is there anything but
 329        * whitespace after it?
 330        */
 331       for ((void)NULL; ch != '\0'; ch = *src++)
 332         if (!isspace(ch))
 333           return (-1);
 334
 335       /*
 336        * Now make sure for cases 2 and 3 that the "extra"
 337        * bits that slopped past the last full byte were
 338        * zeros.  If we don't check them, they become a
 339        * subliminal channel.
 340        */
 341       if (target && target[tarindex] != 0)
 342         return (-1);
 343     }
 344   } else {
 345     /*
 346      * We ended by seeing the end of the string.  Make sure we
 347      * have no partial bytes lying around.
 348      */
 349     if (state != 0)
 350       return (-1);
 351   }
 352
 353   return (tarindex);
 354 }