tor-browser

util.c (5254B)

---

/*
* util.c
*
* Utilities used by the test apps
*
* John A. Foley
* Cisco Systems, Inc.
*/
/*
*
* Copyright (c) 2014-2017, Cisco Systems, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
*   Redistributions of source code must retain the above copyright
*   notice, this list of conditions and the following disclaimer.
*
*   Redistributions in binary form must reproduce the above
*   copyright notice, this list of conditions and the following
*   disclaimer in the documentation and/or other materials provided
*   with the distribution.
*
*   Neither the name of the Cisco Systems, Inc. nor the names of its
*   contributors may be used to endorse or promote products derived
*   from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/

#include "config.h"
#include "util.h"

#include <string.h>
#include <stdint.h>

/* include space for null terminator */
static char bit_string[MAX_PRINT_STRING_LEN + 1];

static inline int hex_char_to_nibble(uint8_t c)
{
   switch (c) {
   case ('0'):
       return 0x0;
   case ('1'):
       return 0x1;
   case ('2'):
       return 0x2;
   case ('3'):
       return 0x3;
   case ('4'):
       return 0x4;
   case ('5'):
       return 0x5;
   case ('6'):
       return 0x6;
   case ('7'):
       return 0x7;
   case ('8'):
       return 0x8;
   case ('9'):
       return 0x9;
   case ('a'):
       return 0xa;
   case ('A'):
       return 0xa;
   case ('b'):
       return 0xb;
   case ('B'):
       return 0xb;
   case ('c'):
       return 0xc;
   case ('C'):
       return 0xc;
   case ('d'):
       return 0xd;
   case ('D'):
       return 0xd;
   case ('e'):
       return 0xe;
   case ('E'):
       return 0xe;
   case ('f'):
       return 0xf;
   case ('F'):
       return 0xf;
   default:
       return -1; /* this flags an error */
   }
}

uint8_t nibble_to_hex_char(uint8_t nibble)
{
   char buf[16] = { '0', '1', '2', '3', '4', '5', '6', '7',
                    '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

   return buf[nibble & 0xF];
}

/*
* hex_string_to_octet_string converts a hexadecimal string
* of length 2 * len to a raw octet string of length len
*/
int hex_string_to_octet_string(char *raw, char *hex, int len)
{
   uint8_t x;
   int tmp;
   int hex_len;

   hex_len = 0;
   while (hex_len < len) {
       tmp = hex_char_to_nibble(hex[0]);
       if (tmp == -1) {
           return hex_len;
       }
       x = (uint8_t)(tmp << 4);
       hex_len++;
       tmp = hex_char_to_nibble(hex[1]);
       if (tmp == -1) {
           return hex_len;
       }
       x |= (tmp & 0xff);
       hex_len++;
       *raw++ = x;
       hex += 2;
   }
   return hex_len;
}

char *octet_string_hex_string(const void *s, int length)
{
   const uint8_t *str = (const uint8_t *)s;
   int i;

   /* double length, since one octet takes two hex characters */
   length *= 2;

   /* truncate string if it would be too long */
   if (length > MAX_PRINT_STRING_LEN) {
       length = MAX_PRINT_STRING_LEN;
   }

   for (i = 0; i < length; i += 2) {
       bit_string[i] = nibble_to_hex_char(*str >> 4);
       bit_string[i + 1] = nibble_to_hex_char(*str++ & 0xF);
   }
   bit_string[i] = 0; /* null terminate string */
   return bit_string;
}

static const char b64chars[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
                              "abcdefghijklmnopqrstuvwxyz0123456789+/";

static int base64_block_to_octet_triple(char *out, char *in)
{
   unsigned char sextets[4] = { 0 };
   int j = 0;
   int i;

   for (i = 0; i < 4; i++) {
       char *p = strchr(b64chars, in[i]);
       if (p != NULL) {
           sextets[i] = (unsigned char)(p - b64chars);
       } else {
           j++;
       }
   }

   out[0] = (sextets[0] << 2) | (sextets[1] >> 4);
   if (j < 2) {
       out[1] = (sextets[1] << 4) | (sextets[2] >> 2);
   }
   if (j < 1) {
       out[2] = (sextets[2] << 6) | sextets[3];
   }
   return j;
}

int base64_string_to_octet_string(char *out, int *pad, char *in, int len)
{
   int k = 0;
   int i = 0;
   int j = 0;

   if (len % 4 != 0) {
       return 0;
   }

   while (i < len && j == 0) {
       j = base64_block_to_octet_triple(out + k, in + i);
       k += 3;
       i += 4;
   }
   *pad = j;
   return i;
}