oid.c

Go to the documentation of this file.

/**
 * @file oid.c
 * @brief OID (Object Identifier)
 *
 * @section License
 *
 * SPDX-License-Identifier: GPL-2.0-or-later
 *
 * Copyright (C) 2010-2024 Oryx Embedded SARL. All rights reserved.
 *
 * This file is part of CycloneCRYPTO Open.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 * @author Oryx Embedded SARL (www.oryx-embedded.com)
 * @version 2.4.4
 **/
 
//Switch to the appropriate trace level
#define TRACE_LEVEL CRYPTO_TRACE_LEVEL
 
//Dependencies
#include "core/crypto.h"
#include "encoding/oid.h"
#include "debug.h"
 
//Check crypto library configuration
#if (OID_SUPPORT == ENABLED)
 
 
/**
 * @brief Check whether the specified object identifier is valid
 * @param[in] oid Pointer to the object identifier
 * @param[in] oidLen Length of the OID, in bytes
 * @return Error code
 **/
 
error_t oidCheck(const uint8_t *oid, size_t oidLen)
{
   size_t i;
   size_t n;
 
   //Check parameters
   if(oid == NULL)
      return ERROR_INVALID_PARAMETER;
 
   //Check the length of the OID
   if(oidLen == 0)
   {
      //Report an error
      return ERROR_INVALID_SYNTAX;
   }
   else if(oidLen > 1)
   {
      //Parse the object identifier
      for(i = 1, n = 2; i < oidLen; i++)
      {
         //Update the total number of nodes
         if((oid[i] & OID_MORE_FLAG) == 0)
         {
            n++;
         }
 
         //SNMP limits object identifier values to a maximum of 128 nodes
         if(n > 128)
            return ERROR_INVALID_SYNTAX;
      }
 
      //Ensure that the last sub-identifier is valid
      if(oid[oidLen - 1] & OID_MORE_FLAG)
         return ERROR_INVALID_SYNTAX;
   }
 
   //The specified OID is valid
   return NO_ERROR;
}
 
 
/**
 * @brief Compare object identifiers
 * @param[in] oid1 Pointer the first OID
 * @param[in] oidLen1 Length of the first OID, in bytes
 * @param[in] oid2 Pointer the second OID
 * @param[in] oidLen2 Length of the second OID, in bytes
 * @return Comparison result
 * @retval 0 Objects identifiers are equal
 * @retval -1 The first OID lexicographically precedes the second OID
 * @retval 1 The second OID lexicographically precedes the first OID
 **/
 
int_t oidComp(const uint8_t *oid1, size_t oidLen1, const uint8_t *oid2,
   size_t oidLen2)
{
   int_t res;
   size_t n1;
   size_t n2;
   size_t pos1;
   size_t pos2;
   bool_t more1;
   bool_t more2;
 
   //Initialize variables
   res = 0;
   n1 = 0;
   n2 = 0;
   pos1 = 0;
   pos2 = 0;
   more1 = TRUE;
   more2 = TRUE;
 
   //Perform lexicographical comparison
   while(res == 0)
   {
      //Extract sub-identifier from first OID
      if(more1)
      {
         if(pos1 >= oidLen1)
         {
            more1 = FALSE;
         }
         else if(pos1 == 0)
         {
            pos1++;
            n1++;
            more1 = FALSE;
         }
         else if(n1 == 0 && oid1[pos1] == OID_MORE_FLAG)
         {
            pos1++;
         }
         else if((oid1[pos1] & OID_MORE_FLAG) != 0)
         {
            pos1++;
            n1++;
         }
         else
         {
            pos1++;
            n1++;
            more1 = FALSE;
         }
      }
 
      //Extract sub-identifier from second OID
      if(more2)
      {
         if(pos2 >= oidLen2)
         {
            more2 = FALSE;
         }
         else if(pos2 == 0)
         {
            pos2++;
            n2++;
            more2 = FALSE;
         }
         else if(n2 == 0 && oid2[pos2] == OID_MORE_FLAG)
         {
            pos2++;
         }
         else if((oid2[pos2] & OID_MORE_FLAG) != 0)
         {
            pos2++;
            n2++;
         }
         else
         {
            pos2++;
            n2++;
            more2 = FALSE;
         }
      }
 
      //Compare sub-identifiers
      if(!more1 && !more2)
      {
         //Check the length of the sub-identifiers
         if(n1 == 0 && n2 == 0)
         {
            res = 0;
            break;
         }
         else if(n1 < n2)
         {
            res = -1;
         }
         else if(n1 > n2)
         {
            res = 1;
         }
         else
         {
            //Compare sub-identifier values
            res = osMemcmp(oid1 + pos1 - n1, oid2 + pos2 - n2, n1);
 
            //Check comparison result
            if(res < 0)
            {
               res = -1;
            }
            else if(res > 0)
            {
               res = 1;
            }
            else
            {
               //Decode next sub-identifiers
               n1 = 0;
               n2 = 0;
               more1 = TRUE;
               more2 = TRUE;
            }
         }
      }
   }
 
   //Return comparison result
   return res;
}
 
 
/**
 * @brief Check whether an OID matches the specified subtree
 * @param[in] oid Pointer to the object identifier
 * @param[in] oidLen Length of the OID, in bytes
 * @param[in] subtree Pointer to the subtree
 * @param[in] subtreeLen Length of the subtree, in bytes
 * @param[in] mask Pointer to the mask
 * @param[in] maskLen Length of the mask, in bytes
 * @return TRUE if the OID matches the specified subtree, else FALSE
 **/
 
bool_t oidMatch(const uint8_t *oid, size_t oidLen, const uint8_t *subtree,
   size_t subtreeLen, const uint8_t *mask, size_t maskLen)
{
   size_t i;
   uint8_t flag;
   size_t oidPos;
   size_t subtreePos;
 
   //Initialize variables
   oidPos = 0;
   subtreePos = 0;
 
   //Check whether the OID matches the specified subtree
   for(i = 0; subtreePos < subtreeLen; i++)
   {
      //Check the length of the OID
      if(oidPos >= oidLen)
         return FALSE;
 
      //The bit mask is extended with 1's to be the required length
      if((i / 8) < maskLen)
      {
         flag = mask[i / 8] & (1U << (7 - (i % 8)));
      }
      else
      {
         flag = 1;
      }
 
      //First node?
      if(i == 0)
      {
         //The mask allows for a simple form of wildcarding
         if(flag)
         {
            //Compare the first sub-identifier
            if((oid[0] / 40) != (subtree[0] / 40))
               return FALSE;
         }
      }
      //Second node?
      else if(i == 1)
      {
         //The mask allows for a simple form of wildcarding
         if(flag)
         {
            //Compare the second sub-identifier
            if((oid[0] % 40) != (subtree[0] % 40))
               return FALSE;
         }
 
         //Jump to the next node
         oidPos = 1;
         subtreePos = 1;
      }
      //Remaining nodes?
      else
      {
         //The mask allows for a simple form of wildcarding
         if(flag)
         {
            //Compare sub-identifiers
            while(1)
            {
               //Compare the current byte
               if(oid[oidPos] != subtree[subtreePos])
                  return FALSE;
 
               //Bit b8 is set to zero to indicate the last byte
               flag = oid[oidPos] & OID_MORE_FLAG;
 
               //Next byte
               oidPos++;
               subtreePos++;
 
               //Last byte of the sub-identifier?
               if(!flag)
                  break;
 
               //Check the length of the OID
               if(oidPos >= oidLen)
                  return FALSE;
 
               //Check the length of the subtree
               if(subtreePos > subtreeLen)
                  return FALSE;
            }
         }
         else
         {
            //Read the OID until the last byte of the sub-identifier is found
            while(1)
            {
               //Bit b8 is set to zero to indicate the last byte
               flag = oid[oidPos] & OID_MORE_FLAG;
 
               //Next byte
               oidPos++;
 
               //Last byte of the sub-identifier?
               if(!flag)
                  break;
 
               //Check the length of the OID
               if(oidPos >= oidLen)
                  return FALSE;
            }
 
            //Read the subtree until the last byte of the sub-identifier is found
            while(1)
            {
               //Bit b8 is set to zero to indicate the last byte
               flag = subtree[subtreePos] & OID_MORE_FLAG;
 
               //Next byte
               subtreePos++;
 
               //Last byte of the sub-identifier?
               if(!flag)
                  break;
 
               //Check the length of the subtree
               if(subtreePos >= subtreeLen)
                  return FALSE;
            }
         }
      }
   }
 
   //The OID matches the specified subtree
   return TRUE;
}
 
 
/**
 * @brief Calculate the number of sub-identifiers
 * @param[in] oid Pointer to the object identifier
 * @param[in] oidLen Length of the OID, in bytes
 * @return Number of sub-identifiers
 **/
 
uint_t oidCountSubIdentifiers(const uint8_t *oid, size_t oidLen)
{
   size_t i;
   uint_t n;
 
   //Check the length of the OID
   if(oidLen == 0)
   {
      //The OID is empty
      n = 0;
   }
   else
   {
      //The first byte encodes two sub-identifiers
      n = 2;
 
      //Parse the object identifier
      for(i = 1; i < oidLen; i++)
      {
         //Update the total number of sub-identifiers
         if((oid[i] & OID_MORE_FLAG) == 0)
         {
            n++;
         }
      }
   }
 
   //Return the total number of sub-identifiers
   return n;
}
 
 
/**
 * @brief Encode OID sub-identifier
 * @param[in] oid Pointer to the object identifier
 * @param[in] maxOidLen Maximum number of bytes the OID can hold
 * @param[in,out] pos Offset where to write the sub-identifier
 * @param[in] value Value of the sub-identifier
 * @return Error code
 **/
 
error_t oidEncodeSubIdentifier(uint8_t *oid, size_t maxOidLen,
   size_t *pos, uint32_t value)
{
   size_t i;
   size_t n;
   uint8_t temp[5];
 
   //Encode the first byte of the sub-identifier
   temp[0] = value & OID_VALUE_MASK;
   //Shift the value to the right
   value >>= 7;
 
   //Encode the remaining bytes
   for(n = 1; value != 0; n++)
   {
      //Encode current byte
      temp[n] = OID_MORE_FLAG | (value & OID_VALUE_MASK);
      //Shift the value to the right
      value >>= 7;
   }
 
   //Sanity check
   if((*pos + n) > maxOidLen)
      return ERROR_BUFFER_OVERFLOW;
 
   //Write the current sub-identifier
   for(i = 0; i < n; i++)
   {
      oid[*pos + i] = temp[n - i - 1];
   }
 
   //Update offset value
   *pos += n;
 
   //Successful processing
   return NO_ERROR;
}
 
 
/**
 * @brief Decode OID sub-identifier
 * @param[in] oid Pointer to the object identifier
 * @param[in] oidLen Length of the OID, in bytes
 * @param[in,out] pos Offset where to read the sub-identifier
 * @param[out] value Value of the sub-identifier
 * @return Error code
 **/
 
error_t oidDecodeSubIdentifier(const uint8_t *oid, size_t oidLen,
   size_t *pos, uint32_t *value)
{
   size_t i;
 
   //Initialize the value of the sub-identifier
   *value = 0;
 
   //Sanity check
   if(*pos >= oidLen)
      return ERROR_INSTANCE_NOT_FOUND;
 
   //Read the OID until the last byte of the sub-identifier is found
   for(i = *pos; i < oidLen; i++)
   {
      //Shift the value to the left
      *value <<= 7;
      //Update value of the sub-identifier
      *value |= oid[i] & OID_VALUE_MASK;
 
      //Bit b8 is set to zero to indicate the last byte
      if((oid[i] & OID_MORE_FLAG) == 0)
      {
         //Update offset value
         *pos = i + 1;
         //Successful processing
         return NO_ERROR;
      }
   }
 
   //The specified OID is not valid
   return ERROR_INVALID_SYNTAX;
}
 
 
/**
 * @brief Convert a string representation of an OID to a binary OID
 * @param[in] str NULL-terminated string representing the OID
 * @param[out] oid Object identifier
 * @param[in] maxOidLen Maximum number of bytes the OID can hold
 * @param[out] oidLen Length of the object identifier
 * @return Error code
 **/
 
error_t oidFromString(const char_t *str, uint8_t *oid, size_t maxOidLen,
   size_t *oidLen)
{
   error_t error;
   size_t i;
   size_t j;
   size_t n;
   uint32_t value;
   uint8_t temp[5];
 
   //Reset the length of the OID
   *oidLen = 0;
 
   //Number of nodes
   i = 0;
   //Initialize the value of the sub-identifier
   value = 0;
 
   //Parse input string
   while(1)
   {
      //Digit found?
      if(osIsdigit(*str))
      {
         //Update the value of the sub-identifier
         value = (value * 10) + (*str - '0');
      }
      //Separator or end of string found?
      else if(*str == '.' || *str == '\0')
      {
         //First node?
         if(i == 0)
         {
            //Check value
            if(value > 6)
            {
               //The conversion failed
               error = ERROR_INVALID_SYNTAX;
               break;
            }
 
            //Encode the first sub-identifier
            temp[0] = value * 40;
            //Prepare to decode the next node
            value = 0;
            //Do not write current sub-identifier yet
            n = 0;
         }
         //Second node?
         else if(i == 1)
         {
            //Check value
            if(value > 39)
            {
               //The conversion failed
               error = ERROR_INVALID_SYNTAX;
               break;
            }
 
            //Encode the second sub-identifier
            temp[0] += value;
            //Prepare to decode the next node
            value = 0;
            //Write the first two sub-identifiers
            n = 1;
         }
         //Remaining nodes?
         else
         {
            //Encode the first byte of the sub-identifier
            temp[0] = value & OID_VALUE_MASK;
            //Shift the value to the right
            value >>= 7;
 
            //Encode the remaining bytes
            for(n = 1; value != 0; n++)
            {
               //Encode current byte
               temp[n] = OID_MORE_FLAG | (value & OID_VALUE_MASK);
               //Shift the value to the right
               value >>= 7;
            }
         }
 
         //Sanity check
         if(n > maxOidLen)
         {
            //Report an error
            error = ERROR_BUFFER_OVERFLOW;
            break;
         }
 
         //Write the current sub-identifier
         for(j = 0; j < n; j++)
         {
            oid[j] = temp[n - j - 1];
         }
 
         //Advance write pointer
         oid += n;
         *oidLen += n;
         maxOidLen -= n;
 
         //Number of sub-identifiers
         i++;
 
         //End of string detected?
         if(*str == '\0')
         {
            //The conversion succeeded
            error = NO_ERROR;
            break;
         }
      }
      //Invalid character...
      else
      {
         //The conversion failed
         error = ERROR_INVALID_SYNTAX;
         break;
      }
 
      //Point to the next character
      str++;
   }
 
   //Return status code
   return error;
}
 
 
/**
 * @brief Convert a binary OID to a string representation
 * @param[in] oid Object identifier
 * @param[in] oidLen Length of the object identifier, in bytes
 * @param[out] str NULL-terminated string representing the OID
 * @param[in] maxStrLen Maximum length of the resulting string
 * @return Pointer to the formatted string
 **/
 
char_t *oidToString(const uint8_t *oid, size_t oidLen, char_t *str,
   size_t maxStrLen)
{
   static char_t buffer[128];
   size_t i;
   size_t n;
   uint32_t value;
   char_t *p;
   char_t temp[12];
 
   //The str parameter is optional
   if(str == NULL)
   {
      //Point to the internal buffer
      str = buffer;
      //Maximum length of the resulting string
      maxStrLen = sizeof(buffer) - 1;
   }
 
   //Point to the beginning of the string
   p = str;
   //Properly terminate the string
   *p = '\0';
 
   //Check the length of the OID
   if(oidLen > 0)
   {
      //Convert the first 2 bytes
      n = osSprintf(temp, "%" PRIu8 ".%" PRIu8 "", oid[0] / 40, oid[0] % 40);
 
      //Sanity check
      if(n <= maxStrLen)
      {
         //Copy the resulting string
         osStrcpy(p, temp);
         //Advance write pointer
         p += n;
         maxStrLen -= n;
      }
 
      //Initialize the value of the sub-identifier
      value = 0;
 
      //Convert the rest of the OID
      for(i = 1; i < oidLen; i++)
      {
         //Shift the value to the left
         value <<= 7;
         //Update the current value
         value |= oid[i] & OID_VALUE_MASK;
 
         //Bit b8 is set to zero to indicate the last byte
         if((oid[i] & OID_MORE_FLAG) == 0)
         {
            //Dump current value
            n = osSprintf(temp, ".%" PRIu32, value);
 
            //Sanity check
            if(n <= maxStrLen)
            {
               //Copy the resulting string
               osStrcpy(p, temp);
               //Advance write pointer
               p += n;
               maxStrLen -= n;
            }
 
            //Prepare to decode the next value
            value = 0;
         }
      }
   }
 
   //Return a pointer to the formatted string
   return str;
}
 
 
/**
 * @brief Convert a bit mask to binary representation
 * @param[in] str NULL-terminated string representing the bit mask
 * @param[out] mask Pointer to the buffer where to store the resulting mask
 * @param[in] maxMaskLen Maximum number of bytes the buffer can hold
 * @param[out] maskLen Length of the mask
 * @return Error code
 **/
 
error_t maskFromString(const char_t *str, uint8_t *mask, size_t maxMaskLen,
   size_t *maskLen)
{
   error_t error;
   size_t i;
   size_t j;
 
   //Point to the first byte
   i = 0;
   //Point to the most-significant bit
   j = 8;
 
   //Parse input string
   while(1)
   {
      //Check current character
      if(*str == '0' || *str == '1')
      {
         //Make sure the output buffer is large enough
         if(i >= maxMaskLen)
         {
            //Report an error
            error = ERROR_BUFFER_OVERFLOW;
            break;
         }
 
         //Update bit mask
         if(*str == '1')
         {
            mask[i] |= (1U << (j - 1));
         }
         else
         {
            mask[i] &= ~(1U << (j - 1));
         }
 
         //Next bit
         j--;
      }
      else if(*str == '\0')
      {
         //End of string detected
         error = NO_ERROR;
         break;
      }
      else
      {
         //Discard any other characters
      }
 
      //Check whether the least-significant bit has been reached
      if(j == 0)
      {
         //Point to the most-significant bit of the next byte
         j = 8;
         i++;
      }
 
      //Point to the next character
      str++;
   }
 
   //Check status code
   if(!error)
   {
      //Incomplete byte?
      if(j < 8)
      {
         //The bit mask is extended with 1's to be the required length
         mask[i] |= (1U << j) - 1;
         //Save the length of the resulting mask
         *maskLen = i + 1;
      }
      else
      {
         //Save the length of the resulting mask
         *maskLen = i;
      }
   }
 
   //Return status code
   return error;
}
 
#endif