sha1.cc

/*
 * Copyright (c) 2008-2014, Pedigree Developers
 *
 * Please see the CONTRIB file in the root of the source tree for a full
 * list of contributors.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
 
/*
 *  sha1.cpp
 *
 *  Copyright (C) 1998, 2009
 *  Paul E. Jones <paulej@packetizer.com>
 *  All Rights Reserved.
 *
 *****************************************************************************
 *  $Id: sha1.cpp 12 2009-06-22 19:34:25Z paulej $
 *****************************************************************************
 *
 *  Description:
 *      This class implements the Secure Hashing Standard as defined
 *      in FIPS PUB 180-1 published April 17, 1995.
 *
 *      The Secure Hashing Standard, which uses the Secure Hashing
 *      Algorithm (SHA), produces a 160-bit message digest for a
 *      given data stream.  In theory, it is highly improbable that
 *      two messages will produce the same message digest.  Therefore,
 *      this algorithm can serve as a means of providing a "fingerprint"
 *      for a message.
 *
 *  Portability Issues:
 *      SHA-1 is defined in terms of 32-bit "words".  This code was
 *      written with the expectation that the processor has at least
 *      a 32-bit machine word size.  If the machine word size is larger,
 *      the code should still function properly.  One caveat to that
 *      is that the input functions taking characters and character arrays
 *      assume that only 8 bits of information are stored in each character.
 *
 *  Caveats:
 *      SHA-1 is designed to work with messages less than 2^64 bits long.
 *      Although SHA-1 allows a message digest to be generated for
 *      messages of any number of bits less than 2^64, this implementation
 *      only works with messages with a length that is a multiple of 8
 *      bits.
 *
 */
 
#include "pedigree/kernel/utilities/sha1/sha1.h"
 
/*
 *  SHA1
 *
 *  Description:
 *      This is the constructor for the sha1 class.
 *
 *  Parameters:
 *      None.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
SHA1::SHA1()
    : H(),
      Length_Low(0),
      Length_High(0),
      Message_Block(),
      Message_Block_Index(0),
      Computed(false),
      Corrupted(false) {
  Reset();
}
 
/*
 *  ~SHA1
 *
 *  Description:
 *      This is the destructor for the sha1 class
 *
 *  Parameters:
 *      None.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
SHA1::~SHA1() {
  // The destructor does nothing
}
 
/*
 *  Reset
 *
 *  Description:
 *      This function will initialize the sha1 class member variables
 *      in preparation for computing a new message digest.
 *
 *  Parameters:
 *      None.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
void SHA1::Reset() {
  Length_Low = 0;
  Length_High = 0;
  Message_Block_Index = 0;
 
  H[0] = 0x67452301;
  H[1] = 0xEFCDAB89;
  H[2] = 0x98BADCFE;
  H[3] = 0x10325476;
  H[4] = 0xC3D2E1F0;
 
  Computed = false;
  Corrupted = false;
}
 
/*
 *  Result
 *
 *  Description:
 *      This function will return the 160-bit message digest into the
 *      array provided.
 *
 *  Parameters:
 *      message_digest_array: [out]
 *          This is an array of five unsigned integers which will be filled
 *          with the message digest that has been computed.
 *
 *  Returns:
 *      True if successful, false if it failed.
 *
 *  Comments:
 *
 */
bool SHA1::Result(unsigned* message_digest_array) {
  int i;  // Counter
 
  if (Corrupted) {
    return false;
  }
 
  if (!Computed) {
    PadMessage();
    Computed = true;
  }
 
  for (i = 0; i < 5; i++) {
    message_digest_array[i] = H[i];
  }
 
  return true;
}
 
/*
 *  Input
 *
 *  Description:
 *      This function accepts an array of octets as the next portion of
 *      the message.
 *
 *  Parameters:
 *      message_array: [in]
 *          An array of characters representing the next portion of the
 *          message.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
void SHA1::Input(const unsigned char* message_array, unsigned length) {
  if (!length) {
    return;
  }
 
  if (Computed || Corrupted) {
    Corrupted = true;
    return;
  }
 
  while (length-- && !Corrupted) {
    Message_Block[Message_Block_Index++] = (*message_array & 0xFF);
 
    Length_Low += 8;
    Length_Low &= 0xFFFFFFFF;  // Force it to 32 bits
    if (Length_Low == 0) {
      Length_High++;
      Length_High &= 0xFFFFFFFF;  // Force it to 32 bits
      if (Length_High == 0) {
        Corrupted = true;  // Message is too long
      }
    }
 
    if (Message_Block_Index == 64) {
      ProcessMessageBlock();
    }
 
    message_array++;
  }
}
 
/*
 *  Input
 *
 *  Description:
 *      This function accepts an array of octets as the next portion of
 *      the message.
 *
 *  Parameters:
 *      message_array: [in]
 *          An array of characters representing the next portion of the
 *          message.
 *      length: [in]
 *          The length of the message_array
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
void SHA1::Input(const char* message_array, unsigned length) {
  Input(reinterpret_cast<unsigned char*>(const_cast<char*>(message_array)), length);
}
 
/*
 *  Input
 *
 *  Description:
 *      This function accepts a single octets as the next message element.
 *
 *  Parameters:
 *      message_element: [in]
 *          The next octet in the message.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
void SHA1::Input(unsigned char message_element) {
  Input(&message_element, 1);
}
 
/*
 *  Input
 *
 *  Description:
 *      This function accepts a single octet as the next message element.
 *
 *  Parameters:
 *      message_element: [in]
 *          The next octet in the message.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
void SHA1::Input(char message_element) {
  Input(reinterpret_cast<unsigned char*>(&message_element), 1);
}
 
/*
 *  operator<<
 *
 *  Description:
 *      This operator makes it convenient to provide character strings to
 *      the SHA1 object for processing.
 *
 *  Parameters:
 *      message_array: [in]
 *          The character array to take as input.
 *
 *  Returns:
 *      A reference to the SHA1 object.
 *
 *  Comments:
 *      Each character is assumed to hold 8 bits of information.
 *
 */
SHA1& SHA1::operator<<(const char* message_array) {
  const char* p = message_array;
 
  while (*p) {
    Input(*p);
    p++;
  }
 
  return *this;
}
 
/*
 *  operator<<
 *
 *  Description:
 *      This operator makes it convenient to provide character strings to
 *      the SHA1 object for processing.
 *
 *  Parameters:
 *      message_array: [in]
 *          The character array to take as input.
 *
 *  Returns:
 *      A reference to the SHA1 object.
 *
 *  Comments:
 *      Each character is assumed to hold 8 bits of information.
 *
 */
SHA1& SHA1::operator<<(const unsigned char* message_array) {
  const unsigned char* p = message_array;
 
  while (*p) {
    Input(*p);
    p++;
  }
 
  return *this;
}
 
/*
 *  operator<<
 *
 *  Description:
 *      This function provides the next octet in the message.
 *
 *  Parameters:
 *      message_element: [in]
 *          The next octet in the message
 *
 *  Returns:
 *      A reference to the SHA1 object.
 *
 *  Comments:
 *      The character is assumed to hold 8 bits of information.
 *
 */
SHA1& SHA1::operator<<(const char message_element) {
  Input(reinterpret_cast<unsigned char*>(const_cast<char*>(&message_element)), 1);
 
  return *this;
}
 
/*
 *  operator<<
 *
 *  Description:
 *      This function provides the next octet in the message.
 *
 *  Parameters:
 *      message_element: [in]
 *          The next octet in the message
 *
 *  Returns:
 *      A reference to the SHA1 object.
 *
 *  Comments:
 *      The character is assumed to hold 8 bits of information.
 *
 */
SHA1& SHA1::operator<<(const unsigned char message_element) {
  Input(&message_element, 1);
 
  return *this;
}
 
/*
 *  ProcessMessageBlock
 *
 *  Description:
 *      This function will process the next 512 bits of the message
 *      stored in the Message_Block array.
 *
 *  Parameters:
 *      None.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *      Many of the variable names in this function, especially the single
 *      character names, were used because those were the names used
 *      in the publication.
 *
 */
void SHA1::ProcessMessageBlock() {
  const unsigned K[] = {// Constants defined for SHA-1
                        0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6};
  int t;                   // Loop counter
  unsigned temp;           // Temporary word value
  unsigned W[80];          // Word sequence
  unsigned A, B, C, D, E;  // Word buffers
 
  /*
   *  Initialize the first 16 words in the array W
   */
  for (t = 0; t < 16; t++) {
    W[t] = Message_Block[t * 4] << 24;
    W[t] |= Message_Block[t * 4 + 1] << 16;
    W[t] |= Message_Block[t * 4 + 2] << 8;
    W[t] |= Message_Block[t * 4 + 3];
  }
 
  for (t = 16; t < 80; t++) {
    W[t] = CircularShift(1, W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]);
  }
 
  A = H[0];
  B = H[1];
  C = H[2];
  D = H[3];
  E = H[4];
 
  for (t = 0; t < 20; t++) {
    temp = CircularShift(5, A) + ((B & C) | ((~B) & D)) + E + W[t] + K[0];
    temp &= 0xFFFFFFFF;
    E = D;
    D = C;
    C = CircularShift(30, B);
    B = A;
    A = temp;
  }
 
  for (t = 20; t < 40; t++) {
    temp = CircularShift(5, A) + (B ^ C ^ D) + E + W[t] + K[1];
    temp &= 0xFFFFFFFF;
    E = D;
    D = C;
    C = CircularShift(30, B);
    B = A;
    A = temp;
  }
 
  for (t = 40; t < 60; t++) {
    temp = CircularShift(5, A) + ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
    temp &= 0xFFFFFFFF;
    E = D;
    D = C;
    C = CircularShift(30, B);
    B = A;
    A = temp;
  }
 
  for (t = 60; t < 80; t++) {
    temp = CircularShift(5, A) + (B ^ C ^ D) + E + W[t] + K[3];
    temp &= 0xFFFFFFFF;
    E = D;
    D = C;
    C = CircularShift(30, B);
    B = A;
    A = temp;
  }
 
  H[0] = (H[0] + A) & 0xFFFFFFFF;
  H[1] = (H[1] + B) & 0xFFFFFFFF;
  H[2] = (H[2] + C) & 0xFFFFFFFF;
  H[3] = (H[3] + D) & 0xFFFFFFFF;
  H[4] = (H[4] + E) & 0xFFFFFFFF;
 
  Message_Block_Index = 0;
}
 
/*
 *  PadMessage
 *
 *  Description:
 *      According to the standard, the message must be padded to an even
 *      512 bits.  The first padding bit must be a '1'.  The last 64 bits
 *      represent the length of the original message.  All bits in between
 *      should be 0.  This function will pad the message according to those
 *      rules by filling the message_block array accordingly.  It will also
 *      call ProcessMessageBlock() appropriately.  When it returns, it
 *      can be assumed that the message digest has been computed.
 *
 *  Parameters:
 *      None.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 *
 */
void SHA1::PadMessage() {
  /*
   *  Check to see if the current message block is too small to hold
   *  the initial padding bits and length.  If so, we will pad the
   *  block, process it, and then continue padding into a second block.
   */
  if (Message_Block_Index > 55) {
    Message_Block[Message_Block_Index++] = 0x80;
    while (Message_Block_Index < 64) {
      Message_Block[Message_Block_Index++] = 0;
    }
 
    ProcessMessageBlock();
 
    while (Message_Block_Index < 56) {
      Message_Block[Message_Block_Index++] = 0;
    }
  } else {
    Message_Block[Message_Block_Index++] = 0x80;
    while (Message_Block_Index < 56) {
      Message_Block[Message_Block_Index++] = 0;
    }
  }
 
  /*
   *  Store the message length as the last 8 octets
   */
  Message_Block[56] = (Length_High >> 24) & 0xFF;
  Message_Block[57] = (Length_High >> 16) & 0xFF;
  Message_Block[58] = (Length_High >> 8) & 0xFF;
  Message_Block[59] = (Length_High) & 0xFF;
  Message_Block[60] = (Length_Low >> 24) & 0xFF;
  Message_Block[61] = (Length_Low >> 16) & 0xFF;
  Message_Block[62] = (Length_Low >> 8) & 0xFF;
  Message_Block[63] = (Length_Low) & 0xFF;
 
  ProcessMessageBlock();
}
 
/*
 *  CircularShift
 *
 *  Description:
 *      This member function will perform a circular shifting operation.
 *
 *  Parameters:
 *      bits: [in]
 *          The number of bits to shift (1-31)
 *      word: [in]
 *          The value to shift (assumes a 32-bit integer)
 *
 *  Returns:
 *      The shifted value.
 *
 *  Comments:
 *
 */
unsigned SHA1::CircularShift(int bits, unsigned word) {
  return ((word << bits) & 0xFFFFFFFF) | ((word & 0xFFFFFFFF) >> (32 - bits));
}