OSX/sec/Security/SecBase64.c

   1 /* /////////////////////////////////////////////////////////////////////////////
   2  * File:        b64.c
   3  *
   4  * Purpose:     Implementation file for the b64 library
   5  *
   6  * Created:     18th October 2004
   7  * Updated:     2nd August 2006
   8  *
   9  * Home:        http://synesis.com.au/software/
  10  *
  11  * Copyright (c) 2004-2006, Matthew Wilson and Synesis Software
  12  * All rights reserved.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are met:
  16  *
  17  * - Redistributions of source code must retain the above copyright notice, this
  18  *   list of conditions and the following disclaimer.
  19  * - Redistributions in binary form must reproduce the above copyright notice,
  20  *   this list of conditions and the following disclaimer in the documentation
  21  *   and/or other materials provided with the distribution.
  22  * - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of
  23  *   any contributors may be used to endorse or promote products derived from
  24  *   this software without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  27  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  29  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  30  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  * POSSIBILITY OF SUCH DAMAGE.
  37  *
  38  * ////////////////////////////////////////////////////////////////////////// */
  39
  40
  41 /** \file b64.c Implementation file for the b64 library
  42  */
  43
  44 #include "SecBase64.h"
  45
  46 #include <assert.h>
  47 #include <string.h>
  48
  49 /* /////////////////////////////////////////////////////////////////////////////
  50  * Constants and definitions
  51  */
  52
  53 #ifndef B64_DOCUMENTATION_SKIP_SECTION
  54 # define NUM_PLAIN_DATA_BYTES        (3)
  55 # define NUM_ENCODED_DATA_BYTES      (4)
  56 #endif /* !B64_DOCUMENTATION_SKIP_SECTION */
  57
  58 /* /////////////////////////////////////////////////////////////////////////////
  59  * Warnings
  60  */
  61
  62 #if defined(_MSC_VER) && \
  63     _MSC_VER < 1000
  64 # pragma warning(disable : 4705)
  65 #endif /* _MSC_VER < 1000 */
  66
  67 /* /////////////////////////////////////////////////////////////////////////////
  68  * Data
  69  */
  70
  71 static const char           b64_chars[] =   "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
  72
  73 static const signed char    b64_indexes[]   =
  74 {
  75     /* 0 - 31 / 0x00 - 0x1f */
  76         -1, -1, -1, -1, -1, -1, -1, -1
  77     ,   -1, -1, -1, -1, -1, -1, -1, -1
  78     ,   -1, -1, -1, -1, -1, -1, -1, -1
  79     ,   -1, -1, -1, -1, -1, -1, -1, -1
  80     /* 32 - 63 / 0x20 - 0x3f */
  81     ,   -1, -1, -1, -1, -1, -1, -1, -1
  82     ,   -1, -1, -1, 62, -1, -1, -1, 63  /* ... , '+', ... '/' */
  83     ,   52, 53, 54, 55, 56, 57, 58, 59  /* '0' - '7' */
  84     ,   60, 61, -1, -1, -1, -1, -1, -1  /* '8', '9', ... */
  85     /* 64 - 95 / 0x40 - 0x5f */
  86     ,   -1, 0,  1,  2,  3,  4,  5,  6   /* ..., 'A' - 'G' */
  87     ,   7,  8,  9,  10, 11, 12, 13, 14  /* 'H' - 'O' */
  88     ,   15, 16, 17, 18, 19, 20, 21, 22  /* 'P' - 'W' */
  89     ,   23, 24, 25, -1, -1, -1, -1, -1  /* 'X', 'Y', 'Z', ... */
  90     /* 96 - 127 / 0x60 - 0x7f */
  91     ,   -1, 26, 27, 28, 29, 30, 31, 32  /* ..., 'a' - 'g' */
  92     ,   33, 34, 35, 36, 37, 38, 39, 40  /* 'h' - 'o' */
  93     ,   41, 42, 43, 44, 45, 46, 47, 48  /* 'p' - 'w' */
  94     ,   49, 50, 51, -1, -1, -1, -1, -1  /* 'x', 'y', 'z', ... */
  95
  96     ,   -1, -1, -1, -1, -1, -1, -1, -1
  97     ,   -1, -1, -1, -1, -1, -1, -1, -1
  98     ,   -1, -1, -1, -1, -1, -1, -1, -1
  99     ,   -1, -1, -1, -1, -1, -1, -1, -1
 100
 101     ,   -1, -1, -1, -1, -1, -1, -1, -1
 102     ,   -1, -1, -1, -1, -1, -1, -1, -1
 103     ,   -1, -1, -1, -1, -1, -1, -1, -1
 104     ,   -1, -1, -1, -1, -1, -1, -1, -1
 105
 106     ,   -1, -1, -1, -1, -1, -1, -1, -1
 107     ,   -1, -1, -1, -1, -1, -1, -1, -1
 108     ,   -1, -1, -1, -1, -1, -1, -1, -1
 109     ,   -1, -1, -1, -1, -1, -1, -1, -1
 110
 111     ,   -1, -1, -1, -1, -1, -1, -1, -1
 112     ,   -1, -1, -1, -1, -1, -1, -1, -1
 113     ,   -1, -1, -1, -1, -1, -1, -1, -1
 114     ,   -1, -1, -1, -1, -1, -1, -1, -1
 115 };
 116
 117 /* /////////////////////////////////////////////////////////////////////////////
 118  * Helper functions
 119  */
 120
 121 /** This function reads in 3 bytes at a time, and translates them into 4
 122  * characters.
 123  */
 124 static size_t SecBase64Encode_(  unsigned char const *src
 125                         ,   size_t              srcSize
 126                         ,   char *const         dest
 127                         ,   size_t              destLen
 128                         ,   unsigned            lineLen
 129                         ,   SecBase64Result     *rc)
 130 {
 131     size_t  total   =   ((srcSize + (NUM_PLAIN_DATA_BYTES - 1)) / NUM_PLAIN_DATA_BYTES) * NUM_ENCODED_DATA_BYTES;
 132
 133     assert(NULL != rc);
 134     *rc = kSecB64_R_OK;
 135
 136     if(lineLen > 0)
 137     {
 138         size_t    numLines    =   (total + (lineLen - 1)) / lineLen;
 139
 140         total += 2 * (numLines - 1);
 141     }
 142
 143     if(NULL == dest)
 144     {
 145         return total;
 146     }
 147     else if(destLen < total)
 148     {
 149         *rc = kSecB64_R_INSUFFICIENT_BUFFER;
 150
 151         return 0;
 152     }
 153     else
 154     {
 155         char    *p      =   dest;
 156         char    *end    =   dest + destLen;
 157         size_t  len     =   0;
 158
 159         for(; NUM_PLAIN_DATA_BYTES <= srcSize; srcSize -= NUM_PLAIN_DATA_BYTES)
 160         {
 161             char    characters[NUM_ENCODED_DATA_BYTES];
 162
 163             /*
 164              *
 165              * |       0       |       1       |       2       |
 166              *
 167              * |               |               |               |
 168              * |       |       |       |       |       |       |
 169              * |   |   |   |   |   |   |   |   |   |   |   |   |
 170              * | | | | | | | | | | | | | | | | | | | | | | | | |
 171              *
 172              * |     0     |     1     |     2     |     3     |
 173              *
 174              */
 175
 176             /* characters[0] is the 6 left-most bits of src[0] */
 177             characters[0] = (char)((src[0] & 0xfc) >> 2);
 178             /* characters[0] is the right-most 2 bits of src[0] and the left-most 4 bits of src[1] */
 179             characters[1] = (char)(((src[0] & 0x03) << 4) + ((src[1] & 0xf0) >> 4));
 180             /* characters[0] is the right-most 4 bits of src[1] and the 2 left-most bits of src[2] */
 181             characters[2] = (char)(((src[1] & 0x0f) << 2) + ((src[2] & 0xc0) >> 6));
 182             /* characters[3] is the right-most 6 bits of src[2] */
 183             characters[3] = (char)(src[2] & 0x3f);
 184
 185 #ifndef __WATCOMC__
 186             assert(characters[0] >= 0 && characters[0] < 64);
 187             assert(characters[1] >= 0 && characters[1] < 64);
 188             assert(characters[2] >= 0 && characters[2] < 64);
 189             assert(characters[3] >= 0 && characters[3] < 64);
 190 #endif /* __WATCOMC__ */
 191
 192             src += NUM_PLAIN_DATA_BYTES;
 193             *p++ = b64_chars[(unsigned char)characters[0]];
 194             assert(NULL != strchr(b64_chars, *(p-1)));
 195             ++len;
 196             assert(len != lineLen);
 197
 198             *p++ = b64_chars[(unsigned char)characters[1]];
 199             assert(NULL != strchr(b64_chars, *(p-1)));
 200             ++len;
 201             assert(len != lineLen);
 202
 203             *p++ = b64_chars[(unsigned char)characters[2]];
 204             assert(NULL != strchr(b64_chars, *(p-1)));
 205             ++len;
 206             assert(len != lineLen);
 207
 208             *p++ = b64_chars[(unsigned char)characters[3]];
 209             assert(NULL != strchr(b64_chars, *(p-1)));
 210
 211             if( ++len == lineLen &&
 212                 p != end)
 213             {
 214                 *p++ = '\r';
 215                 *p++ = '\n';
 216                 len = 0;
 217             }
 218         }
 219
 220         if(0 != srcSize)
 221         {
 222             /* Deal with the overspill, by boosting it up to three bytes (using 0s)
 223              * and then appending '=' for any missing characters.
 224              *
 225              * This is done into a temporary buffer, so we can call ourselves and
 226              * have the output continue to be written direct to the destination.
 227              */
 228
 229             unsigned char   dummy[NUM_PLAIN_DATA_BYTES];
 230             size_t          i;
 231
 232             for(i = 0; i < srcSize; ++i)
 233             {
 234                 dummy[i] = *src++;
 235             }
 236
 237             for(; i < NUM_PLAIN_DATA_BYTES; ++i)
 238             {
 239                 dummy[i] = '\0';
 240             }
 241
 242             SecBase64Encode_(&dummy[0], NUM_PLAIN_DATA_BYTES, p, NUM_ENCODED_DATA_BYTES * (1 + 2), 0, rc);
 243
 244             for(p += 1 + srcSize; srcSize++ < NUM_PLAIN_DATA_BYTES; )
 245             {
 246                 *p++ = '=';
 247             }
 248         }
 249
 250         return total;
 251     }
 252 }
 253
 254 /** This function reads in a character string in 4-character chunks, and writes
 255  * out the converted form in 3-byte chunks to the destination.
 256  */
 257 static size_t SecBase64Decode_(  char const      *src
 258                         ,   size_t          srcLen
 259                         ,   unsigned char   *dest
 260                         ,   size_t          destSize
 261                         ,   unsigned        flags
 262                         ,   char const      **badChar
 263                         ,   SecBase64Result *rc)
 264 {
 265     const size_t    wholeChunks     =   (srcLen / NUM_ENCODED_DATA_BYTES);
 266     const size_t    remainderBytes  =   (srcLen % NUM_ENCODED_DATA_BYTES);
 267     size_t          maxTotal        =   (wholeChunks + (0 != remainderBytes)) * NUM_PLAIN_DATA_BYTES;
 268     unsigned char   *dest_          =   dest;
 269
 270     ((void)remainderBytes);
 271
 272     assert(NULL != badChar);
 273     assert(NULL != rc);
 274
 275     *badChar    =   NULL;
 276     *rc         =   kSecB64_R_OK;
 277
 278     if(NULL == dest)
 279     {
 280         return maxTotal;
 281     }
 282     else if(destSize < maxTotal)
 283     {
 284         *rc = kSecB64_R_INSUFFICIENT_BUFFER;
 285
 286         return 0;
 287     }
 288     else
 289     {
 290         /* Now we iterate through the src, collecting together four characters
 291          * at a time from the Base-64 alphabet, until the end-point is reached.
 292          *
 293          *
 294          */
 295
 296         char const          *begin      =   src;
 297         char const  *const  end         =   begin + srcLen;
 298         size_t              currIndex   =   0;
 299         size_t              numPads     =   0;
 300         signed char         indexes[NUM_ENCODED_DATA_BYTES];    /* 4 */
 301
 302         for(; begin != end; ++begin)
 303         {
 304             const char  ch  =   *begin;
 305
 306             if('=' == ch)
 307             {
 308                 assert(currIndex < NUM_ENCODED_DATA_BYTES);
 309
 310                 indexes[currIndex++] = '\0';
 311
 312                 ++numPads;
 313             }
 314             else
 315             {
 316                 signed char ix   =   b64_indexes[(unsigned char)ch];
 317
 318                 if(-1 == ix)
 319                 {
 320                     switch(ch)
 321                     {
 322                         case    ' ':
 323                         case    '\t':
 324                         case    '\b':
 325                         case    '\v':
 326                             if(kSecB64_F_STOP_ON_UNEXPECTED_WS & flags)
 327                             {
 328                                 *rc         =   kSecB64_R_DATA_ERROR;
 329                                 *badChar    =   begin;
 330                                 return 0;
 331                             }
 332                             else
 333                             {
 334                                 /* Fall through */
 335                             }
 336                         case    '\r':
 337                         case    '\n':
 338                             continue;
 339                         default:
 340                             if(kSecB64_F_STOP_ON_UNKNOWN_CHAR & flags)
 341                             {
 342                                 *rc         =   kSecB64_R_DATA_ERROR;
 343                                 *badChar    =   begin;
 344                                 return 0;
 345                             }
 346                             else
 347                             {
 348                                 continue;
 349                             }
 350                     }
 351                 }
 352                 else
 353                 {
 354                     numPads = 0;
 355
 356                     assert(currIndex < NUM_ENCODED_DATA_BYTES);
 357
 358                     indexes[currIndex++] = ix;
 359                 }
 360             }
 361
 362             if(NUM_ENCODED_DATA_BYTES == currIndex)
 363             {
 364                 unsigned char   bytes[NUM_PLAIN_DATA_BYTES];        /* 3 */
 365
 366                 bytes[0] = (unsigned char)((indexes[0] << 2) + ((indexes[1] & 0x30) >> 4));
 367
 368                 currIndex = 0;
 369
 370                 *dest++ = bytes[0];
 371                 if(2 != numPads)
 372                 {
 373                     bytes[1] = (unsigned char)(((indexes[1] & 0xf) << 4) + ((indexes[2] & 0x3c) >> 2));
 374
 375                     *dest++ = bytes[1];
 376
 377                     if(1 != numPads)
 378                     {
 379                         bytes[2] = (unsigned char)(((indexes[2] & 0x3) << 6) + indexes[3]);
 380
 381                         *dest++ = bytes[2];
 382                     }
 383                 }
 384                 if(0 != numPads)
 385                 {
 386                     break;
 387                 }
 388             }
 389         }
 390
 391         return (size_t)(dest - dest_);
 392     }
 393 }
 394
 395 /* /////////////////////////////////////////////////////////////////////////////
 396  * API functions
 397  */
 398
 399 size_t SecBase64Encode(void const *src, size_t srcSize, char *dest, size_t destLen)
 400 {
 401     /* Use Null Object (Variable) here for rc, so do not need to check
 402      * elsewhere.
 403      */
 404     SecBase64Result  rc_;
 405
 406     return SecBase64Encode_((unsigned char const*)src, srcSize, dest, destLen, 0, &rc_);
 407 }
 408
 409 size_t SecBase64Encode2( void const *src
 410                 ,   size_t          srcSize
 411                 ,   char            *dest
 412                 ,   size_t          destLen
 413                 ,   unsigned        flags
 414                 ,   int             lineLen /* = -1 */
 415                 ,   SecBase64Result *rc     /* = NULL */)
 416 {
 417     /* Use Null Object (Variable) here for rc, so do not need to check
 418      * elsewhere
 419      */
 420     SecBase64Result  rc_;
 421     if(NULL == rc)
 422     {
 423         rc = &rc_;
 424     }
 425
 426     switch(kSecB64_F_LINE_LEN_MASK & flags)
 427     {
 428         case    kSecB64_F_LINE_LEN_USE_PARAM:
 429             if(lineLen >= 0)
 430             {
 431                 break;
 432             }
 433             /* Fall through to 64 */
 434         case    kSecB64_F_LINE_LEN_64:
 435             lineLen = 64;
 436             break;
 437         case    kSecB64_F_LINE_LEN_76:
 438             lineLen = 76;
 439             break;
 440         default:
 441             assert(!"Bad line length flag specified to SecBase64Encode2()");
 442         case    kSecB64_F_LINE_LEN_INFINITE:
 443             lineLen = 0;
 444             break;
 445     }
 446
 447     assert(0 == (lineLen % 4));
 448
 449     return SecBase64Encode_((unsigned char const*)src, srcSize, dest, destLen, (unsigned)lineLen, rc);
 450 }
 451
 452 size_t SecBase64Decode(char const *src, size_t srcLen, void *dest, size_t destSize)
 453 {
 454     /* Use Null Object (Variable) here for rc and badChar, so do not need to
 455      * check elsewhere.
 456      */
 457     char const  *badChar_;
 458     SecBase64Result      rc_;
 459
 460     return SecBase64Decode_(src, srcLen, (unsigned char*)dest, destSize, kSecB64_F_STOP_ON_NOTHING, &badChar_, &rc_);
 461 }
 462
 463 size_t SecBase64Decode2( char const  *src
 464                 ,   size_t      srcLen
 465                 ,   void        *dest
 466                 ,   size_t      destSize
 467                 ,   unsigned    flags
 468                 ,   char const  **badChar   /* = NULL */
 469                 ,   SecBase64Result      *rc         /* = NULL */)
 470 {
 471     char const      *badChar_;
 472     SecBase64Result          rc_;
 473
 474     /* Use Null Object (Variable) here for rc and badChar, so do not need to
 475      * check elsewhere.
 476      */
 477     if(NULL == badChar)
 478     {
 479         badChar = &badChar_;
 480     }
 481     if(NULL == rc)
 482     {
 483         rc = &rc_;
 484     }
 485
 486     return SecBase64Decode_(src, srcLen, (unsigned char*)dest, destSize, flags, badChar, rc);
 487 }
 488
 489 /* ////////////////////////////////////////////////////////////////////////// */