src/system/libroot/posix/crypt/SHA256.cpp

   1 /*
   2  * Copyright 2008, Ingo Weinhold, ingo_weinhold@gmx.de.
   3  * Distributed under the terms of the MIT License.
   4  */
   5
   6
   7 #include "SHA256.h"
   8
   9 #include <stdio.h>
  10 #include <string.h>
  11
  12 #include <ByteOrder.h>
  13
  14
  15 namespace BPrivate {
  16
  17
  18 static const uint32 kChunkSize = 64;    // 64 bytes == 512 bits
  19
  20 static const uint32 kRounds[64] = {
  21    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
  22    0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
  23    0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
  24    0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
  25    0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
  26    0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
  27    0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
  28    0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
  29 };
  30 static const uint32 kHash[8] = {
  31         0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
  32         0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
  33 };
  34
  35
  36 static inline uint32
  37 rotate_right(uint32 value, int bits)
  38 {
  39         return (value >> bits) | (value << (32 - bits));
  40 }
  41
  42
  43 //      #pragma mark -
  44
  45
  46 SHA256::SHA256()
  47 {
  48         Init();
  49 }
  50
  51
  52 SHA256::~SHA256()
  53 {
  54 }
  55
  56
  57 void
  58 SHA256::Init()
  59 {
  60         memcpy(fHash, kHash, sizeof(kHash));
  61
  62         fBytesInBuffer = 0;
  63         fMessageSize = 0;
  64         fDigested = false;
  65 }
  66
  67
  68 void
  69 SHA256::Update(const void* _buffer, size_t size)
  70 {
  71         const uint8* buffer = (const uint8*)_buffer;
  72         fMessageSize += size;
  73
  74         while (fBytesInBuffer + size >= kChunkSize) {
  75                 size_t toCopy = kChunkSize - fBytesInBuffer;
  76                 memcpy((uint8*)fBuffer + fBytesInBuffer, buffer, toCopy);
  77                 buffer += toCopy;
  78                 size -= toCopy;
  79
  80                 _ProcessChunk();
  81                 fBytesInBuffer = 0;
  82         }
  83
  84         if (size > 0) {
  85                 memcpy((uint8*)fBuffer + fBytesInBuffer, buffer, size);
  86                 fBytesInBuffer += size;
  87         }
  88 }
  89
  90
  91 const uint8*
  92 SHA256::Digest()
  93 {
  94         if (!fDigested) {
  95                 // We need to append a 1 bit, append padding with 0 bits, and append
  96                 // the message size in bits (64 bit big-endian int), so that the whole
  97                 // is chunk-aligned. So we either have to process one last chunk or two
  98                 // chunks.
  99
 100                 // append the 1 bit
 101                 ((uint8*)fBuffer)[fBytesInBuffer] = 0x80;
 102                 fBytesInBuffer++;
 103
 104                 // if the message size doesn't fit anymore, we pad the chunk and
 105                 // process it
 106                 if (fBytesInBuffer > kChunkSize - 8) {
 107                         memset((uint8*)fBuffer + fBytesInBuffer, 0,
 108                                 kChunkSize - fBytesInBuffer);
 109                         _ProcessChunk();
 110                         fBytesInBuffer = 0;
 111                 }
 112
 113                 // pad the buffer
 114                 if (fBytesInBuffer < kChunkSize - 8) {
 115                         memset((uint8*)fBuffer + fBytesInBuffer, 0,
 116                                 kChunkSize - 8 - fBytesInBuffer);
 117                 }
 118
 119                 // write the (big-endian) message size in bits
 120                 uint64* target = (uint64*)((uint8*)fBuffer + kChunkSize - 8);
 121                 *target = B_HOST_TO_BENDIAN_INT64((uint64)fMessageSize * 8);
 122
 123                 _ProcessChunk();
 124
 125                 // set digest
 126                 for (int i = 0; i < 8; i++)
 127                         fDigest[i] = B_HOST_TO_BENDIAN_INT32(fHash[i]);
 128
 129                 fDigested = true;
 130         }
 131
 132         return (uint8*)fDigest;
 133 }
 134
 135
 136 void
 137 SHA256::_ProcessChunk()
 138 {
 139         // convert endianess -- the data are supposed to be a stream of
 140         // 32 bit big-endian integers
 141         #if B_HOST_IS_LENDIAN
 142                 for (int i = 0; i < (int)kChunkSize / 4; i++)
 143                         fBuffer[i] = B_SWAP_INT32(fBuffer[i]);
 144         #endif
 145
 146         // pre-process buffer (extend to 64 elements)
 147         for (int i = 16; i < 64; i++) {
 148                 uint32 v0 = fBuffer[i - 15];
 149                 uint32 v1 = fBuffer[i - 2];
 150                 uint32 s0 = rotate_right(v0, 7) ^ rotate_right(v0, 18) ^ (v0 >> 3);
 151                 uint32 s1 = rotate_right(v1, 17) ^ rotate_right(v1, 19) ^ (v1 >> 10);
 152                 fBuffer[i] = fBuffer[i - 16] + s0 + fBuffer[i - 7] + s1;
 153         }
 154
 155         uint32 a = fHash[0];
 156         uint32 b = fHash[1];
 157         uint32 c = fHash[2];
 158         uint32 d = fHash[3];
 159         uint32 e = fHash[4];
 160         uint32 f = fHash[5];
 161         uint32 g = fHash[6];
 162         uint32 h = fHash[7];
 163
 164         // process the buffer
 165         for (int i = 0; i < 64; i++) {
 166                 uint32 s0 = rotate_right(a, 2) ^ rotate_right(a, 13)
 167                         ^ rotate_right(a, 22);
 168                 uint32 maj = (a & b) ^ (a & c) ^ (b & c);
 169                 uint32 t2 = s0 + maj;
 170                 uint32 s1 = rotate_right(e, 6) ^ rotate_right(e, 11)
 171                         ^ rotate_right(e, 25);
 172                 uint32 ch = (e & f) ^ (~e & g);
 173                 uint32 t1 = h + s1 + ch + kRounds[i] + fBuffer[i];
 174
 175                 h = g;
 176                 g = f;
 177                 f = e;
 178                 e = d + t1;
 179                 d = c;
 180                 c = b;
 181                 b = a;
 182                 a = t1 + t2;
 183         }
 184
 185         fHash[0] += a;
 186         fHash[1] += b;
 187         fHash[2] += c;
 188         fHash[3] += d;
 189         fHash[4] += e;
 190         fHash[5] += f;
 191         fHash[6] += g;
 192         fHash[7] += h;
 193 }
 194
 195
 196 } // namespace BPrivate