openbsd-compat/base64.c

   1 /*      $OpenBSD: base64.c,v 1.5 2006/10/21 09:55:03 otto 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 /* OPENBSD ORIGINAL: lib/libc/net/base64.c */
  46
  47 #include "includes.h"
  48
  49 #if (!defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP)) || (!defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON))
  50
  51 #include <sys/types.h>
  52 #include <sys/param.h>
  53 #include <sys/socket.h>
  54 #include <netinet/in.h>
  55 #include <arpa/inet.h>
  56
  57 #include <ctype.h>
  58 #include <stdio.h>
  59
  60 #include <stdlib.h>
  61 #include <string.h>
  62
  63 #include "base64.h"
  64
  65 static const char Base64[] =
  66         "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  67 static const char Pad64 = '=';
  68
  69 /* (From RFC1521 and draft-ietf-dnssec-secext-03.txt)
  70    The following encoding technique is taken from RFC 1521 by Borenstein
  71    and Freed.  It is reproduced here in a slightly edited form for
  72    convenience.
  73
  74    A 65-character subset of US-ASCII is used, enabling 6 bits to be
  75    represented per printable character. (The extra 65th character, "=",
  76    is used to signify a special processing function.)
  77
  78    The encoding process represents 24-bit groups of input bits as output
  79    strings of 4 encoded characters. Proceeding from left to right, a
  80    24-bit input group is formed by concatenating 3 8-bit input groups.
  81    These 24 bits are then treated as 4 concatenated 6-bit groups, each
  82    of which is translated into a single digit in the base64 alphabet.
  83
  84    Each 6-bit group is used as an index into an array of 64 printable
  85    characters. The character referenced by the index is placed in the
  86    output string.
  87
  88                          Table 1: The Base64 Alphabet
  89
  90       Value Encoding  Value Encoding  Value Encoding  Value Encoding
  91           0 A            17 R            34 i            51 z
  92           1 B            18 S            35 j            52 0
  93           2 C            19 T            36 k            53 1
  94           3 D            20 U            37 l            54 2
  95           4 E            21 V            38 m            55 3
  96           5 F            22 W            39 n            56 4
  97           6 G            23 X            40 o            57 5
  98           7 H            24 Y            41 p            58 6
  99           8 I            25 Z            42 q            59 7
 100           9 J            26 a            43 r            60 8
 101          10 K            27 b            44 s            61 9
 102          11 L            28 c            45 t            62 +
 103          12 M            29 d            46 u            63 /
 104          13 N            30 e            47 v
 105          14 O            31 f            48 w         (pad) =
 106          15 P            32 g            49 x
 107          16 Q            33 h            50 y
 108
 109    Special processing is performed if fewer than 24 bits are available
 110    at the end of the data being encoded.  A full encoding quantum is
 111    always completed at the end of a quantity.  When fewer than 24 input
 112    bits are available in an input group, zero bits are added (on the
 113    right) to form an integral number of 6-bit groups.  Padding at the
 114    end of the data is performed using the '=' character.
 115
 116    Since all base64 input is an integral number of octets, only the
 117          -------------------------------------------------
 118    following cases can arise:
 119
 120        (1) the final quantum of encoding input is an integral
 121            multiple of 24 bits; here, the final unit of encoded
 122            output will be an integral multiple of 4 characters
 123            with no "=" padding,
 124        (2) the final quantum of encoding input is exactly 8 bits;
 125            here, the final unit of encoded output will be two
 126            characters followed by two "=" padding characters, or
 127        (3) the final quantum of encoding input is exactly 16 bits;
 128            here, the final unit of encoded output will be three
 129            characters followed by one "=" padding character.
 130    */
 131
 132 #if !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP)
 133 int
 134 b64_ntop(u_char const *src, size_t srclength, char *target, size_t targsize)
 135 {
 136         size_t datalength = 0;
 137         u_char input[3];
 138         u_char output[4];
 139         u_int i;
 140
 141         while (2 < srclength) {
 142                 input[0] = *src++;
 143                 input[1] = *src++;
 144                 input[2] = *src++;
 145                 srclength -= 3;
 146
 147                 output[0] = input[0] >> 2;
 148                 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
 149                 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
 150                 output[3] = input[2] & 0x3f;
 151
 152                 if (datalength + 4 > targsize)
 153                         return (-1);
 154                 target[datalength++] = Base64[output[0]];
 155                 target[datalength++] = Base64[output[1]];
 156                 target[datalength++] = Base64[output[2]];
 157                 target[datalength++] = Base64[output[3]];
 158         }
 159
 160         /* Now we worry about padding. */
 161         if (0 != srclength) {
 162                 /* Get what's left. */
 163                 input[0] = input[1] = input[2] = '\0';
 164                 for (i = 0; i < srclength; i++)
 165                         input[i] = *src++;
 166
 167                 output[0] = input[0] >> 2;
 168                 output[1] = ((input[0] & 0x03) << 4) + (input[1] >> 4);
 169                 output[2] = ((input[1] & 0x0f) << 2) + (input[2] >> 6);
 170
 171                 if (datalength + 4 > targsize)
 172                         return (-1);
 173                 target[datalength++] = Base64[output[0]];
 174                 target[datalength++] = Base64[output[1]];
 175                 if (srclength == 1)
 176                         target[datalength++] = Pad64;
 177                 else
 178                         target[datalength++] = Base64[output[2]];
 179                 target[datalength++] = Pad64;
 180         }
 181         if (datalength >= targsize)
 182                 return (-1);
 183         target[datalength] = '\0';      /* Returned value doesn't count \0. */
 184         return (datalength);
 185 }
 186 #endif /* !defined(HAVE_B64_NTOP) && !defined(HAVE___B64_NTOP) */
 187
 188 #if !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON)
 189
 190 /* skips all whitespace anywhere.
 191    converts characters, four at a time, starting at (or after)
 192    src from base - 64 numbers into three 8 bit bytes in the target area.
 193    it returns the number of data bytes stored at the target, or -1 on error.
 194  */
 195
 196 int
 197 b64_pton(char const *src, u_char *target, size_t targsize)
 198 {
 199         u_int tarindex, state;
 200         int ch;
 201         char *pos;
 202
 203         state = 0;
 204         tarindex = 0;
 205
 206         while ((ch = *src++) != '\0') {
 207                 if (isspace(ch))        /* Skip whitespace anywhere. */
 208                         continue;
 209
 210                 if (ch == Pad64)
 211                         break;
 212
 213                 pos = strchr(Base64, ch);
 214                 if (pos == 0)           /* A non-base64 character. */
 215                         return (-1);
 216
 217                 switch (state) {
 218                 case 0:
 219                         if (target) {
 220                                 if (tarindex >= targsize)
 221                                         return (-1);
 222                                 target[tarindex] = (pos - Base64) << 2;
 223                         }
 224                         state = 1;
 225                         break;
 226                 case 1:
 227                         if (target) {
 228                                 if (tarindex + 1 >= targsize)
 229                                         return (-1);
 230                                 target[tarindex]   |=  (pos - Base64) >> 4;
 231                                 target[tarindex+1]  = ((pos - Base64) & 0x0f)
 232                                                         << 4 ;
 233                         }
 234                         tarindex++;
 235                         state = 2;
 236                         break;
 237                 case 2:
 238                         if (target) {
 239                                 if (tarindex + 1 >= targsize)
 240                                         return (-1);
 241                                 target[tarindex]   |=  (pos - Base64) >> 2;
 242                                 target[tarindex+1]  = ((pos - Base64) & 0x03)
 243                                                         << 6;
 244                         }
 245                         tarindex++;
 246                         state = 3;
 247                         break;
 248                 case 3:
 249                         if (target) {
 250                                 if (tarindex >= targsize)
 251                                         return (-1);
 252                                 target[tarindex] |= (pos - Base64);
 253                         }
 254                         tarindex++;
 255                         state = 0;
 256                         break;
 257                 }
 258         }
 259
 260         /*
 261          * We are done decoding Base-64 chars.  Let's see if we ended
 262          * on a byte boundary, and/or with erroneous trailing characters.
 263          */
 264
 265         if (ch == Pad64) {              /* We got a pad char. */
 266                 ch = *src++;            /* Skip it, get next. */
 267                 switch (state) {
 268                 case 0:         /* Invalid = in first position */
 269                 case 1:         /* Invalid = in second position */
 270                         return (-1);
 271
 272                 case 2:         /* Valid, means one byte of info */
 273                         /* Skip any number of spaces. */
 274                         for (; ch != '\0'; ch = *src++)
 275                                 if (!isspace(ch))
 276                                         break;
 277                         /* Make sure there is another trailing = sign. */
 278                         if (ch != Pad64)
 279                                 return (-1);
 280                         ch = *src++;            /* Skip the = */
 281                         /* Fall through to "single trailing =" case. */
 282                         /* FALLTHROUGH */
 283
 284                 case 3:         /* Valid, means two bytes of info */
 285                         /*
 286                          * We know this char is an =.  Is there anything but
 287                          * whitespace after it?
 288                          */
 289                         for (; ch != '\0'; ch = *src++)
 290                                 if (!isspace(ch))
 291                                         return (-1);
 292
 293                         /*
 294                          * Now make sure for cases 2 and 3 that the "extra"
 295                          * bits that slopped past the last full byte were
 296                          * zeros.  If we don't check them, they become a
 297                          * subliminal channel.
 298                          */
 299                         if (target && target[tarindex] != 0)
 300                                 return (-1);
 301                 }
 302         } else {
 303                 /*
 304                  * We ended by seeing the end of the string.  Make sure we
 305                  * have no partial bytes lying around.
 306                  */
 307                 if (state != 0)
 308                         return (-1);
 309         }
 310
 311         return (tarindex);
 312 }
 313
 314 #endif /* !defined(HAVE_B64_PTON) && !defined(HAVE___B64_PTON) */
 315 #endif