src/lib/base64.c

/*
   Bacula(R) - The Network Backup Solution

   Copyright (C) 2000-2020 Kern Sibbald

   The original author of Bacula is Kern Sibbald, with contributions
   from many others, a complete list can be found in the file AUTHORS.

   You may use this file and others of this release according to the
   license defined in the LICENSE file, which includes the Affero General
   Public License, v3.0 ("AGPLv3") and some additional permissions and
   terms pursuant to its AGPLv3 Section 7.

   This notice must be preserved when any source code is
   conveyed and/or propagated.

   Bacula(R) is a registered trademark of Kern Sibbald.
*/
/*
 *   Generic base 64 input and output routines
 *
 *    Written by Kern E. Sibbald, March MM.
 */


#include "bacula.h"


#ifdef TEST_MODE
#include <glob.h>
#endif


static uint8_t const base64_digits[64] =
{
  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
  'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
  'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm',
  'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
  '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', '+', '/'
};

static int base64_inited = 0;
static uint8_t base64_map[256];


/* Initialize the Base 64 conversion routines */
void
base64_init(void)
{
   int i;
   memset(base64_map, 0, sizeof(base64_map));
   for (i=0; i<64; i++)
      base64_map[(uint8_t)base64_digits[i]] = i;
   base64_inited = 1;
}

/* Convert a value to base64 characters.
 * The result is stored in where, which
 * must be at least 8 characters long.
 *
 * Returns the number of characters
 * stored (not including the EOS).
 */
int
to_base64(int64_t value, char *where)
{
   uint64_t val;
   int i = 0;
   int n;

   /* Handle negative values */
   if (value < 0) {
      where[i++] = '-';
      value = -value;
   }

   /* Determine output size */
   val = value;
   do {
      val >>= 6;
      i++;
   } while (val);
   n = i;

   /* Output characters */
   val = value;
   where[i] = 0;
   do {
      where[--i] = base64_digits[val & (uint64_t)0x3F];
      val >>= 6;
   } while (val);
   return n;
}

/*
 * Convert the Base 64 characters in where to
 * a value. No checking is done on the validity
 * of the characters!!
 *
 * Returns the value.
 */
int
from_base64(int64_t *value, char *where)
{
   uint64_t val = 0;
   int i, neg;

   if (!base64_inited)
      base64_init();
   /* Check if it is negative */
   i = neg = 0;
   if (where[i] == '-') {
      i++;
      neg = 1;
   }
   /* Construct value */
   while (where[i] != 0 && where[i] != ' ') {
      val <<= 6;
      val += base64_map[(uint8_t)where[i++]];
   }

   *value = neg ? -(int64_t)val : (int64_t)val;
   return i;
}


/*
 * Encode binary data in bin of len bytes into
 * buf as base64 characters.
 *
 * If compatible is true, the bin_to_base64 routine will be compatible
 * with what the rest of the world uses.
 *
 *  Returns: the number of characters stored not
 *           including the EOS
 */
int
bin_to_base64(char *buf, int buflen, char *bin, int binlen, int compatible)
{
   uint32_t reg, save, mask;
   int rem, i;
   int j = 0;

   reg = 0;
   rem = 0;
   buflen--;                       /* allow for storing EOS */
   for (i=0; i < binlen; ) {
      if (rem < 6) {
         reg <<= 8;
         if (compatible) {
            reg |= (uint8_t)bin[i++];
         } else {
            reg |= (int8_t)bin[i++];
         }
         rem += 8;
      }
      save = reg;
      reg >>= (rem - 6);
      if (j < buflen) {
         buf[j++] = base64_digits[reg & 0x3F];
      }
      reg = save;
      rem -= 6;
   }
   if (rem && j < buflen) {
      mask = (1 << rem) - 1;
      if (compatible) {
         buf[j++] = base64_digits[(reg & mask) << (6 - rem)];
      } else {
         buf[j++] = base64_digits[reg & mask];
      }
   }
   buf[j] = 0;
   return j;
}

/*
 * Decode base64 data in bin of len bytes into
 * buf as binary characters.
 *
 * the base64_to_bin routine is compatible with what the rest of the world
 * uses.
 *
 * 'dest_size' must be big enough! Giving the right size here could fail as
 * we consider 'srclen' as an unpadded size, even if 'src' is padded
 * we suggest to use dest_size=srclen for easiness or at least
 * dest_size=((srclen + 3) / 4) * 3) for optimization lovers
 *
 *  Returns: the number of characters stored not
 *           including the EOS
 */
int base64_to_bin(char *dest, int dest_size, char *src, int srclen)
{
   int nprbytes;
   uint8_t *bufout;
   uint8_t *bufplain = (uint8_t*) dest;
   const uint8_t *bufin;

   if (!base64_inited)
      base64_init();

   if (dest_size < (((srclen + 3) / 4) * 3)) {
      /* dest buffer too small */
      *dest = 0;
      return 0;
   }

   bufin = (const uint8_t *) src;
   while ((*bufin != ' ') && (srclen != 0)) {
      bufin++;
      srclen--;
   }

   nprbytes = bufin - (const uint8_t *) src;
   bufin = (const uint8_t *) src;
   bufout = (uint8_t *) bufplain;

   while (nprbytes > 4)
   {
      *(bufout++) = (base64_map[bufin[0]] << 2 | base64_map[bufin[1]] >> 4);
      *(bufout++) = (base64_map[bufin[1]] << 4 | base64_map[bufin[2]] >> 2);
      *(bufout++) = (base64_map[bufin[2]] << 6 | base64_map[bufin[3]]);
      bufin += 4;
      nprbytes -= 4;
   }

   /* Bacula base64 strings are not always padded with = */
   if (nprbytes > 1) {
      *(bufout++) = (base64_map[bufin[0]] << 2 | base64_map[bufin[1]] >> 4);
   }
   if (nprbytes > 2) {
      *(bufout++) = (base64_map[bufin[1]] << 4 | base64_map[bufin[2]] >> 2);
   }
   if (nprbytes > 3) {
      *(bufout++) = (base64_map[bufin[2]] << 6 | base64_map[bufin[3]]);
   }
   *bufout = 0;

   return (bufout - (uint8_t *) dest);
}

#ifdef BIN_TEST
int main(int argc, char *argv[])
{
   int len;
   char buf[100];
   char junk[100];
   int i;

#ifdef xxxx
   int xx = 0;
   for (i=0; i < 1000; i++) {
      bin_to_base64(buf, sizeof(buf), (char *)&xx, 4, true);
      printf("xx=%s\n", buf);
      xx++;
   }
#endif
   junk[0] = 0xFF;
   for (i=1; i<100; i++) {
      junk[i] = junk[i-1]-1;
   }
   len = bin_to_base64(buf, sizeof(buf), junk, 16, true);
   printf("len=%d junk=%s\n", len, buf);

   strcpy(junk, "This is a sample stringa");
   len = bin_to_base64(buf, sizeof(buf), junk, strlen(junk), true);
   buf[len] = 0;
   base64_to_bin(junk, sizeof(junk), buf, len);
   printf("buf=<%s>\n", junk);
   return 0;
}
#endif

#ifdef TEST_MODE
static int errfunc(const char *epath, int eernoo)
{
  printf("in errfunc\n");
  return 1;
}


/*
 * Test the base64 routines by encoding and decoding
 * lstat() packets.
 */
int main(int argc, char *argv[])
{
   char where[500];
   int i;
   glob_t my_glob;
   char *fname;
   struct stat statp;
   struct stat statn;
   int debug_level = 0;
   char *p;
   int32_t j;
   time_t t = 1028712799;

   if (argc > 1 && strcmp(argv[1], "-v") == 0)
      debug_level++;

   base64_init();

   my_glob.gl_offs = 0;
   glob("/etc/grub.conf", GLOB_MARK, errfunc, &my_glob);

   for (i=0; my_glob.gl_pathv[i]; i++) {
      fname = my_glob.gl_pathv[i];
      if (lstat(fname, &statp) < 0) {
         berrno be;
         printf("Cannot stat %s: %s\n", fname, be.bstrerror(errno));
         continue;
      }
      encode_stat(where, &statp, sizeof(statp), 0, 0);

      printf("Encoded stat=%s\n", where);

#ifdef xxx
      p = where;
      p += to_base64((int64_t)(statp.st_atime), p);
      *p++ = ' ';
      p += to_base64((int64_t)t, p);
      printf("%s %s\n", fname, where);

      printf("%s %lld\n", "st_dev", (int64_t)statp.st_dev);
      printf("%s %lld\n", "st_ino", (int64_t)statp.st_ino);
      printf("%s %lld\n", "st_mode", (int64_t)statp.st_mode);
      printf("%s %lld\n", "st_nlink", (int64_t)statp.st_nlink);
      printf("%s %lld\n", "st_uid", (int64_t)statp.st_uid);
      printf("%s %lld\n", "st_gid", (int64_t)statp.st_gid);
      printf("%s %lld\n", "st_rdev", (int64_t)statp.st_rdev);
      printf("%s %lld\n", "st_size", (int64_t)statp.st_size);
      printf("%s %lld\n", "st_blksize", (int64_t)statp.st_blksize);
      printf("%s %lld\n", "st_blocks", (int64_t)statp.st_blocks);
      printf("%s %lld\n", "st_atime", (int64_t)statp.st_atime);
      printf("%s %lld\n", "st_mtime", (int64_t)statp.st_mtime);
      printf("%s %lld\n", "st_ctime", (int64_t)statp.st_ctime);
#endif

      if (debug_level)
         printf("%s: len=%d val=%s\n", fname, strlen(where), where);

      decode_stat(where, &statn, sizeof(statn), &j);

      if (statp.st_dev != statn.st_dev ||
          statp.st_ino != statn.st_ino ||
          statp.st_mode != statn.st_mode ||
          statp.st_nlink != statn.st_nlink ||
          statp.st_uid != statn.st_uid ||
          statp.st_gid != statn.st_gid ||
          statp.st_rdev != statn.st_rdev ||
          statp.st_size != statn.st_size ||
          statp.st_blksize != statn.st_blksize ||
          statp.st_blocks != statn.st_blocks ||
          statp.st_atime != statn.st_atime ||
          statp.st_mtime != statn.st_mtime ||
          statp.st_ctime != statn.st_ctime) {

         printf("%s: %s\n", fname, where);
         encode_stat(where, &statn, sizeof(statn), 0, 0);
         printf("%s: %s\n", fname, where);
         printf("NOT EQAL\n");
      }

   }
   globfree(&my_glob);

   printf("%d files examined\n", i);

   to_base64(UINT32_MAX, where);
   printf("UINT32_MAX=%s\n", where);

   return 0;
}
#endif

#ifndef TEST_PROGRAM
#define TEST_PROGRAM_A
#endif

#ifdef TEST_PROGRAM
#include "unittests.h"

static const unsigned char rnddata[16] = {
   0xa5, 0x7d, 0xa3, 0xc4, 0x2c, 0xa0, 0x08, 0xe9, 0x32, 0xb9, 0xc7, 0x84, 0xf6, 0xd3, 0xdf, 0x4f
};
static const char *resb16 = "pX2jxCygCOkyuceE9tPfTw";
static const char *resb8 = "q83v7c";
#define VARREF    0xABCDEFEDC

int main()
{
   Unittests base64_test("base64_test");
   char buf[30];
   char binbuf[30];
   uint len;
   bool check_cont;
   int64_t var;

   base64_init();
/*
   for (int a=0; a < 16; a++){
      fprintf(stderr, "%c", rnddata[a]);
   }
*/
   /* encode reference binary data to base64 */
   len = bin_to_base64(buf, 30, (char*)rnddata, 16, true);
   ok(len == strlen(resb16), "Checking bin_to_base64 encoded length");
   ok(strcmp(resb16, buf) == 0, "Checking bin_to_base64 encoded data");
   /* decode reference base64 data to bin*/
   len = base64_to_bin(binbuf, 30, (char*)resb16, strlen(resb16));
   ok(len == 16, "Checking base64_to_bin decoded length");
   check_cont = true;
   for (uint a = 0; a < len; a++){
      if ((unsigned char)binbuf[a] != rnddata[a]){
         check_cont = false;
      }
   }
   ok(check_cont, "Checking base64_to_bin decoded data");
   /* decode the encoded base64 data to bin */
   len = base64_to_bin(binbuf, 30, buf, strlen(buf));
   ok(len == 16, "Checking base64_to_bin decoded length - encoded");
   check_cont = true;
   for (uint a = 0; a < len; a++){
      if ((unsigned char)binbuf[a] != rnddata[a]){
         check_cont = false;
      }
   }
   ok(check_cont, "Checking base64_to_bin decoded data - encoded");
   /* encode reference variable to base64 */
   len = to_base64(VARREF, buf);
   ok(len == 6, "Checking to_base64 encode length");
   ok(strcmp(resb8, buf) == 0, "Checking to_base64 encoded data");
   /* decode reference data to bin */
   len = from_base64(&var, (char*)resb8);
   ok(var == VARREF, "Checking from_base64 decoded data");
   ok(len == 6, "Checking from_base64 decoded length");
   /* decode encoded data to bin */
   len = from_base64(&var, buf);
   ok(var == VARREF, "Checking from_base64 decoded data - encoded");
   ok(len == 6, "Checking from_base64 decoded length - encoded");
   return report();
};
#endif /* TEST_PROGRAM */