wtf/SHA1.cpp

   1 /*
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  30
  31 // A straightforward SHA-1 implementation based on RFC 3174.
  32 // http://www.ietf.org/rfc/rfc3174.txt
  33 // The names of functions and variables (such as "a", "b", and "f") follow notations in RFC 3174.
  34
  35 #include "config.h"
  36 #include "SHA1.h"
  37
  38 #include "Assertions.h"
  39 #ifndef NDEBUG
  40 #include "StringExtras.h"
  41 #include "text/CString.h"
  42 #endif
  43
  44 namespace WTF {
  45
  46 #ifdef NDEBUG
  47 static inline void testSHA1() { }
  48 #else
  49 static bool isTestSHA1Done;
  50
  51 static void expectSHA1(CString input, int repeat, CString expected)
  52 {
  53     SHA1 sha1;
  54     for (int i = 0; i < repeat; ++i)
  55         sha1.addBytes(reinterpret_cast<const uint8_t*>(input.data()), input.length());
  56     Vector<uint8_t, 20> digest;
  57     sha1.computeHash(digest);
  58     char* buffer = 0;
  59     CString actual = CString::newUninitialized(40, buffer);
  60     for (size_t i = 0; i < 20; ++i) {
  61         snprintf(buffer, 3, "%02X", digest.at(i));
  62         buffer += 2;
  63     }
  64     ASSERT_WITH_MESSAGE(actual == expected, "input: %s, repeat: %d, actual: %s, expected: %s", input.data(), repeat, actual.data(), expected.data());
  65 }
  66
  67 static void testSHA1()
  68 {
  69     if (isTestSHA1Done)
  70         return;
  71     isTestSHA1Done = true;
  72
  73     // Examples taken from sample code in RFC 3174.
  74     expectSHA1("abc", 1, "A9993E364706816ABA3E25717850C26C9CD0D89D");
  75     expectSHA1("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq", 1, "84983E441C3BD26EBAAE4AA1F95129E5E54670F1");
  76     expectSHA1("a", 1000000, "34AA973CD4C4DAA4F61EEB2BDBAD27316534016F");
  77     expectSHA1("0123456701234567012345670123456701234567012345670123456701234567", 10, "DEA356A2CDDD90C7A7ECEDC5EBB563934F460452");
  78 }
  79 #endif
  80
  81 static inline uint32_t f(int t, uint32_t b, uint32_t c, uint32_t d)
  82 {
  83     ASSERT(t >= 0 && t < 80);
  84     if (t < 20)
  85         return (b & c) | ((~b) & d);
  86     if (t < 40)
  87         return b ^ c ^ d;
  88     if (t < 60)
  89         return (b & c) | (b & d) | (c & d);
  90     return b ^ c ^ d;
  91 }
  92
  93 static inline uint32_t k(int t)
  94 {
  95     ASSERT(t >= 0 && t < 80);
  96     if (t < 20)
  97         return 0x5a827999;
  98     if (t < 40)
  99         return 0x6ed9eba1;
 100     if (t < 60)
 101         return 0x8f1bbcdc;
 102     return 0xca62c1d6;
 103 }
 104
 105 static inline uint32_t rotateLeft(int n, uint32_t x)
 106 {
 107     ASSERT(n >= 0 && n < 32);
 108     return (x << n) | (x >> (32 - n));
 109 }
 110
 111 SHA1::SHA1()
 112 {
 113     // FIXME: Move unit tests somewhere outside the constructor. See bug 55853.
 114     testSHA1();
 115     reset();
 116 }
 117
 118 void SHA1::addBytes(const uint8_t* input, size_t length)
 119 {
 120     while (length--) {
 121         ASSERT(m_cursor < 64);
 122         m_buffer[m_cursor++] = *input++;
 123         ++m_totalBytes;
 124         if (m_cursor == 64)
 125             processBlock();
 126     }
 127 }
 128
 129 void SHA1::computeHash(Vector<uint8_t, 20>& digest)
 130 {
 131     finalize();
 132
 133     digest.clear();
 134     digest.resize(20);
 135     for (size_t i = 0; i < 5; ++i) {
 136         // Treat hashValue as a big-endian value.
 137         uint32_t hashValue = m_hash[i];
 138         for (int j = 0; j < 4; ++j) {
 139             digest[4 * i + (3 - j)] = hashValue & 0xFF;
 140             hashValue >>= 8;
 141         }
 142     }
 143
 144     reset();
 145 }
 146
 147 void SHA1::finalize()
 148 {
 149     ASSERT(m_cursor < 64);
 150     m_buffer[m_cursor++] = 0x80;
 151     if (m_cursor > 56) {
 152         // Pad out to next block.
 153         while (m_cursor < 64)
 154             m_buffer[m_cursor++] = 0x00;
 155         processBlock();
 156     }
 157
 158     for (size_t i = m_cursor; i < 56; ++i)
 159         m_buffer[i] = 0x00;
 160
 161     // Write the length as a big-endian 64-bit value.
 162     uint64_t bits = m_totalBytes * 8;
 163     for (int i = 0; i < 8; ++i) {
 164         m_buffer[56 + (7 - i)] = bits & 0xFF;
 165         bits >>= 8;
 166     }
 167     m_cursor = 64;
 168     processBlock();
 169 }
 170
 171 void SHA1::processBlock()
 172 {
 173     ASSERT(m_cursor == 64);
 174
 175     uint32_t w[80] = { 0 };
 176     for (int t = 0; t < 16; ++t)
 177         w[t] = (m_buffer[t * 4] << 24) | (m_buffer[t * 4 + 1] << 16) | (m_buffer[t * 4 + 2] << 8) | m_buffer[t * 4 + 3];
 178     for (int t = 16; t < 80; ++t)
 179         w[t] = rotateLeft(1, w[t - 3] ^ w[t - 8] ^ w[t - 14] ^ w[t - 16]);
 180
 181     uint32_t a = m_hash[0];
 182     uint32_t b = m_hash[1];
 183     uint32_t c = m_hash[2];
 184     uint32_t d = m_hash[3];
 185     uint32_t e = m_hash[4];
 186
 187     for (int t = 0; t < 80; ++t) {
 188         uint32_t temp = rotateLeft(5, a) + f(t, b, c, d) + e + w[t] + k(t);
 189         e = d;
 190         d = c;
 191         c = rotateLeft(30, b);
 192         b = a;
 193         a = temp;
 194     }
 195
 196     m_hash[0] += a;
 197     m_hash[1] += b;
 198     m_hash[2] += c;
 199     m_hash[3] += d;
 200     m_hash[4] += e;
 201
 202     m_cursor = 0;
 203 }
 204
 205 void SHA1::reset()
 206 {
 207     m_cursor = 0;
 208     m_totalBytes = 0;
 209     m_hash[0] = 0x67452301;
 210     m_hash[1] = 0xefcdab89;
 211     m_hash[2] = 0x98badcfe;
 212     m_hash[3] = 0x10325476;
 213     m_hash[4] = 0xc3d2e1f0;
 214
 215     // Clear the buffer after use in case it's sensitive.
 216     memset(m_buffer, 0, sizeof(m_buffer));
 217 }
 218
 219 } // namespace WTF