external/bsd/dhcp/dist/dst/base64.c

   1 /*      $NetBSD: base64.c,v 1.6 2014/07/12 12:09:37 spz Exp $   */
   2 /*
   3  * Copyright (c) 2004,2009 by Internet Systems Consortium, Inc. ("ISC")
   4  * Copyright (c) 1996-2003 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 ISC DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  16  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  *   Internet Systems Consortium, Inc.
  19  *   950 Charter Street
  20  *   Redwood City, CA 94063
  21  *   <info@isc.org>
  22  *   https://www.isc.org/
  23  */
  24
  25 #include <sys/cdefs.h>
  26 __RCSID("$NetBSD: base64.c,v 1.6 2014/07/12 12:09:37 spz Exp $");
  27
  28 /*
  29  * Portions Copyright (c) 1995 by International Business Machines, Inc.
  30  *
  31  * International Business Machines, Inc. (hereinafter called IBM) grants
  32  * permission under its copyrights to use, copy, modify, and distribute this
  33  * Software with or without fee, provided that the above copyright notice and
  34  * all paragraphs of this notice appear in all copies, and that the name of IBM
  35  * not be used in connection with the marketing of any product incorporating
  36  * the Software or modifications thereof, without specific, written prior
  37  * permission.
  38  *
  39  * To the extent it has a right to do so, IBM grants an immunity from suit
  40  * under its patents, if any, for the use, sale or manufacture of products to
  41  * the extent that such products are used for performing Domain Name System
  42  * dynamic updates in TCP/IP networks by means of the Software.  No immunity is
  43  * granted for any product per se or for any other function of any product.
  44  *
  45  * THE SOFTWARE IS PROVIDED "AS IS", AND IBM DISCLAIMS ALL WARRANTIES,
  46  * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
  47  * PARTICULAR PURPOSE.  IN NO EVENT SHALL IBM BE LIABLE FOR ANY SPECIAL,
  48  * DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER ARISING
  49  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE, EVEN
  50  * IF IBM IS APPRISED OF THE POSSIBILITY OF SUCH DAMAGES.
  51  */
  52
  53 #if !defined(LINT) && !defined(CODECENTER)
  54 static const char rcsid[] = "Id: base64.c,v 1.6 2009/11/24 02:06:56 sar Exp ";
  55 #endif /* not lint */
  56
  57 #include <sys/types.h>
  58 #include <sys/param.h>
  59 #include <sys/socket.h>
  60
  61 #include <netinet/in.h>
  62 #include <arpa/inet.h>
  63
  64 #include <ctype.h>
  65 #include <stdio.h>
  66 #include <stdlib.h>
  67 #include <string.h>
  68
  69 #include <sys/socket.h>
  70
  71 #include "cdefs.h"
  72 #include "osdep.h"
  73 #include "arpa/nameser.h"
  74 #include "dst_internal.h"
  75
  76 #define Assert(Cond) if (!(Cond)) abort()
  77
  78 static const char Base64[] =
  79         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  80 static const char Pad64 = '=';
  81
  82 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
  83    The following encoding technique is taken from RFC 1521 by Borenstein
  84    and Freed.  It is reproduced here in a slightly edited form for
  85    convenience.
  86
  87    A 65-character subset of US-ASCII is used, enabling 6 bits to be
  88    represented per printable character. (The extra 65th character, "=",
  89    is used to signify a special processing function.)
  90
  91    The encoding process represents 24-bit groups of input bits as output
  92    strings of 4 encoded characters. Proceeding from left to right, a
  93    24-bit input group is formed by concatenating 3 8-bit input groups.
  94    These 24 bits are then treated as 4 concatenated 6-bit groups, each
  95    of which is translated into a single digit in the base64 alphabet.
  96
  97    Each 6-bit group is used as an index into an array of 64 printable
  98    characters. The character referenced by the index is placed in the
  99    output string.
 100
 101                          Table 1: The Base64 Alphabet
 102
 103       Value Encoding  Value Encoding  Value Encoding  Value Encoding
 104           0 A            17 R            34 i            51 z
 105           1 B            18 S            35 j            52 0
 106           2 C            19 T            36 k            53 1
 107           3 D            20 U            37 l            54 2
 108           4 E            21 V            38 m            55 3
 109           5 F            22 W            39 n            56 4
 110           6 G            23 X            40 o            57 5
 111           7 H            24 Y            41 p            58 6
 112           8 I            25 Z            42 q            59 7
 113           9 J            26 a            43 r            60 8
 114          10 K            27 b            44 s            61 9
 115          11 L            28 c            45 t            62 +
 116          12 M            29 d            46 u            63 /
 117          13 N            30 e            47 v
 118          14 O            31 f            48 w         (pad) =
 119          15 P            32 g            49 x
 120          16 Q            33 h            50 y
 121
 122    Special processing is performed if fewer than 24 bits are available
 123    at the end of the data being encoded.  A full encoding quantum is
 124    always completed at the end of a quantity.  When fewer than 24 input
 125    bits are available in an input group, zero bits are added (on the
 126    right) to form an integral number of 6-bit groups.  Padding at the
 127    end of the data is performed using the '=' character.
 128
 129    Since all base64 input is an integral number of octets, only the
 130          -------------------------------------------------
 131    following cases can arise:
 132
 133        (1) the final quantum of encoding input is an integral
 134            multiple of 24 bits; here, the final unit of encoded
 135            output will be an integral multiple of 4 characters
 136            with no "=" padding,
 137        (2) the final quantum of encoding input is exactly 8 bits;
 138            here, the final unit of encoded output will be two
 139            characters followed by two "=" padding characters, or
 140        (3) the final quantum of encoding input is exactly 16 bits;
 141            here, the final unit of encoded output will be three
 142            characters followed by one "=" padding character.
 143    */
 144
 145 int
 146 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize) {
 147         size_t datalength = 0;
 148         u_char input[3];
 149         u_char output[4];
 150         size_t i;
 151
 152         while (2 < srclength) {
 153                 input[0] = *src++;
 154                 input[1] = *src++;
 155                 input[2] = *src++;
 156                 srclength -= 3;
 157
 158                 output[0] = input[0] >> 2;
 159                 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
 160                 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
 161                 output[3] = input[2] & 0x3f;
 162                 Assert(output[0] < 64);
 163                 Assert(output[1] < 64);
 164                 Assert(output[2] < 64);
 165                 Assert(output[3] < 64);
 166
 167                 if (datalength + 4 > targsize)
 168                         return (-1);
 169                 target[datalength++] = Base64[output[0]];
 170                 target[datalength++] = Base64[output[1]];
 171                 target[datalength++] = Base64[output[2]];
 172                 target[datalength++] = Base64[output[3]];
 173         }
 174
 175         /* Now we worry about padding. */
 176         if (0 != srclength) {
 177                 /* Get what's left. */
 178                 input[0] = input[1] = input[2] = '\0';
 179                 for (i = 0; i < srclength; i++)
 180                         input[i] = *src++;
 181
 182                 output[0] = input[0] >> 2;
 183                 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
 184                 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
 185                 Assert(output[0] < 64);
 186                 Assert(output[1] < 64);
 187                 Assert(output[2] < 64);
 188
 189                 if (datalength + 4 > targsize)
 190                         return (-1);
 191                 target[datalength++] = Base64[output[0]];
 192                 target[datalength++] = Base64[output[1]];
 193                 if (srclength == 1)
 194                         target[datalength++] = Pad64;
 195                 else
 196                         target[datalength++] = Base64[output[2]];
 197                 target[datalength++] = Pad64;
 198         }
 199         if (datalength >= targsize)
 200                 return (-1);
 201         target[datalength] = '\0';      /* Returned value doesn't count \0. */
 202         return (datalength);
 203 }
 204
 205 /* skips all whitespace anywhere.
 206    converts characters, four at a time, starting at (or after)
 207    src from base - 64 numbers into three 8 bit bytes in the target area.
 208    it returns the number of data bytes stored at the target, or -1 on error.
 209  */
 210
 211 int
 212 b64_pton(char const *src, u_char *target, size_t targsize)
 213 {
 214         int tarindex, state, ch;
 215         char *pos;
 216
 217         state = 0;
 218         tarindex = 0;
 219
 220         while ((ch = *src++) != '\0') {
 221                 if (isspace(ch))        /* Skip whitespace anywhere. */
 222                         continue;
 223
 224                 if (ch == Pad64)
 225                         break;
 226
 227                 pos = strchr(Base64, ch);
 228                 if (pos == 0)           /* A non-base64 character. */
 229                         return (-1);
 230
 231                 switch (state) {
 232                 case 0:
 233                         if (target) {
 234                                 if ((size_t)tarindex >= targsize)
 235                                         return (-1);
 236                                 target[tarindex] = (pos - Base64) << 2;
 237                         }
 238                         state = 1;
 239                         break;
 240                 case 1:
 241                         if (target) {
 242                                 if ((size_t)tarindex + 1 >= targsize)
 243                                         return (-1);
 244                                 target[tarindex]   |=  (pos - Base64) >> 4;
 245                                 target[tarindex+1]  = ((pos - Base64) & 0x0f)
 246                                                         << 4 ;
 247                         }
 248                         tarindex++;
 249                         state = 2;
 250                         break;
 251                 case 2:
 252                         if (target) {
 253                                 if ((size_t)tarindex + 1 >= targsize)
 254                                         return (-1);
 255                                 target[tarindex]   |=  (pos - Base64) >> 2;
 256                                 target[tarindex+1]  = ((pos - Base64) & 0x03)
 257                                                         << 6;
 258                         }
 259                         tarindex++;
 260                         state = 3;
 261                         break;
 262                 case 3:
 263                         if (target) {
 264                                 if ((size_t)tarindex >= targsize)
 265                                         return (-1);
 266                                 target[tarindex] |= (pos - Base64);
 267                         }
 268                         tarindex++;
 269                         state = 0;
 270                         break;
 271                 default:
 272                         abort();
 273                 }
 274         }
 275
 276         /*
 277          * We are done decoding Base-64 chars.  Let's see if we ended
 278          * on a byte boundary, and/or with erroneous trailing characters.
 279          */
 280
 281         if (ch == Pad64) {              /* We got a pad char. */
 282                 ch = *src++;            /* Skip it, get next. */
 283                 switch (state) {
 284                 case 0:         /* Invalid = in first position */
 285                 case 1:         /* Invalid = in second position */
 286                         return (-1);
 287
 288                 case 2:         /* Valid, means one byte of info */
 289                         /* Skip any number of spaces. */
 290                         for ((void)NULL; ch != '\0'; ch = *src++)
 291                                 if (!isspace(ch))
 292                                         break;
 293                         /* Make sure there is another trailing = sign. */
 294                         if (ch != Pad64)
 295                                 return (-1);
 296                         ch = *src++;            /* Skip the = */
 297                         /* Fall through to "single trailing =" case. */
 298                         /* FALLTHROUGH */
 299
 300                 case 3:         /* Valid, means two bytes of info */
 301                         /*
 302                          * We know this char is an =.  Is there anything but
 303                          * whitespace after it?
 304                          */
 305                         for ((void)NULL; ch != '\0'; ch = *src++)
 306                                 if (!isspace(ch))
 307                                         return (-1);
 308
 309                         /*
 310                          * Now make sure for cases 2 and 3 that the "extra"
 311                          * bits that slopped past the last full byte were
 312                          * zeros.  If we don't check them, they become a
 313                          * subliminal channel.
 314                          */
 315                         if (target && target[tarindex] != 0)
 316                                 return (-1);
 317                 }
 318         } else {
 319                 /*
 320                  * We ended by seeing the end of the string.  Make sure we
 321                  * have no partial bytes lying around.
 322                  */
 323                 if (state != 0)
 324                         return (-1);
 325         }
 326
 327         return (tarindex);
 328 }