LibCrypto: Add the SHA-384 hash algorithm

This is a truncated version of SHA-512, so it was fairly trivial.

Userland/Libraries/LibCrypto/Hash/SHA2.cpp

@@ -142,6 +142,122 @@ SHA256::DigestType SHA256::peek()
     return digest;
 }
 
+inline void SHA384::transform(const u8* data)
+{
+    u64 m[80];
+
+    size_t i = 0;
+    for (size_t j = 0; i < 16; ++i, j += 8) {
+        m[i] = ((u64)data[j] << 56) | ((u64)data[j + 1] << 48) | ((u64)data[j + 2] << 40) | ((u64)data[j + 3] << 32) | ((u64)data[j + 4] << 24) | ((u64)data[j + 5] << 16) | ((u64)data[j + 6] << 8) | (u64)data[j + 7];
+    }
+
+    for (; i < Rounds; ++i) {
+        m[i] = SIGN1(m[i - 2]) + m[i - 7] + SIGN0(m[i - 15]) + m[i - 16];
+    }
+
+    auto a = m_state[0], b = m_state[1],
+         c = m_state[2], d = m_state[3],
+         e = m_state[4], f = m_state[5],
+         g = m_state[6], h = m_state[7];
+
+    for (size_t i = 0; i < Rounds; ++i) {
+        // Note : SHA384 uses the SHA512 constants.
+        auto temp0 = h + EP1(e) + CH(e, f, g) + SHA512Constants::RoundConstants[i] + m[i];
+        auto temp1 = EP0(a) + MAJ(a, b, c);
+        h = g;
+        g = f;
+        f = e;
+        e = d + temp0;
+        d = c;
+        c = b;
+        b = a;
+        a = temp0 + temp1;
+    }
+
+    m_state[0] += a;
+    m_state[1] += b;
+    m_state[2] += c;
+    m_state[3] += d;
+    m_state[4] += e;
+    m_state[5] += f;
+    m_state[6] += g;
+    m_state[7] += h;
+}
+
+void SHA384::update(const u8* message, size_t length)
+{
+    for (size_t i = 0; i < length; ++i) {
+        if (m_data_length == BlockSize) {
+            transform(m_data_buffer);
+            m_bit_length += 1024;
+            m_data_length = 0;
+        }
+        m_data_buffer[m_data_length++] = message[i];
+    }
+}
+
+SHA384::DigestType SHA384::digest()
+{
+    auto digest = peek();
+    reset();
+    return digest;
+}
+
+SHA384::DigestType SHA384::peek()
+{
+    DigestType digest;
+    size_t i = m_data_length;
+
+    if (BlockSize == m_data_length) {
+        transform(m_data_buffer);
+        m_bit_length += BlockSize * 8;
+        m_data_length = 0;
+        i = 0;
+    }
+
+    if (m_data_length < FinalBlockDataSize) {
+        m_data_buffer[i++] = 0x80;
+        while (i < FinalBlockDataSize)
+            m_data_buffer[i++] = 0x00;
+
+    } else {
+        // First, complete a block with some padding.
+        m_data_buffer[i++] = 0x80;
+        while (i < BlockSize)
+            m_data_buffer[i++] = 0x00;
+        transform(m_data_buffer);
+
+        // Then start another block with BlockSize - 8 bytes of zeros
+        __builtin_memset(m_data_buffer, 0, FinalBlockDataSize);
+    }
+
+    // append total message length
+    m_bit_length += m_data_length * 8;
+    m_data_buffer[BlockSize - 1] = m_bit_length;
+    m_data_buffer[BlockSize - 2] = m_bit_length >> 8;
+    m_data_buffer[BlockSize - 3] = m_bit_length >> 16;
+    m_data_buffer[BlockSize - 4] = m_bit_length >> 24;
+    m_data_buffer[BlockSize - 5] = m_bit_length >> 32;
+    m_data_buffer[BlockSize - 6] = m_bit_length >> 40;
+    m_data_buffer[BlockSize - 7] = m_bit_length >> 48;
+    m_data_buffer[BlockSize - 8] = m_bit_length >> 56;
+
+    transform(m_data_buffer);
+
+    // SHA uses big-endian and we assume little-endian
+    // FIXME: looks like a thing for AK::NetworkOrdered,
+    //        but he doesn't support shifting operations
+    for (size_t i = 0; i < 8; ++i) {
+        digest.data[i + 0] = (m_state[0] >> (56 - i * 8)) & 0x000000ff;
+        digest.data[i + 8] = (m_state[1] >> (56 - i * 8)) & 0x000000ff;
+        digest.data[i + 16] = (m_state[2] >> (56 - i * 8)) & 0x000000ff;
+        digest.data[i + 24] = (m_state[3] >> (56 - i * 8)) & 0x000000ff;
+        digest.data[i + 32] = (m_state[4] >> (56 - i * 8)) & 0x000000ff;
+        digest.data[i + 40] = (m_state[5] >> (56 - i * 8)) & 0x000000ff;
+    }
+    return digest;
+}
+
 inline void SHA512::transform(const u8* data)
 {
     u64 m[80];