106 lines
2.7 KiB
C++
106 lines
2.7 KiB
C++
// via-rng.cpp - written and placed in public domain by Jeffrey Walton and Uri Blumenthal.
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#include "pch.h"
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#include "config.h"
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#include "cryptlib.h"
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#include "secblock.h"
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#include "padlkrng.h"
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#include "cpu.h"
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// The Padlock Security Engine RNG has a few items to be aware of. You can
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// find copies of the Programmer's manual, Cryptography Research Inc audit
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// report, and other goodies at http://www.cryptopp.com/wiki/VIA_Padlock.
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#if CRYPTOPP_MSC_VERSION
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# pragma warning(disable: 4702)
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#endif
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NAMESPACE_BEGIN(CryptoPP)
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std::string PadlockRNG::AlgorithmProvider() const
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{
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return "Padlock";
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}
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PadlockRNG::PadlockRNG(word32 divisor)
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: m_divisor(DivisorHelper(divisor)), m_msr(0)
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{
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#if defined(CRYPTOPP_X86_ASM_AVAILABLE)
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if (!HasPadlockRNG())
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#endif
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throw PadlockRNG_Err("PadlockRNG", "PadlockRNG generator not available");
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}
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void PadlockRNG::GenerateBlock(byte *output, size_t size)
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{
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CRYPTOPP_UNUSED(output); CRYPTOPP_UNUSED(size);
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#if defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(__GNUC__)
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while (size)
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{
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__asm__ __volatile__
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(
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#if (CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X64)
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"mov %1, %%rdi ;\n"
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"movl %2, %%edx ;\n"
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#else
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"mov %1, %%edi ;\n"
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"movl %2, %%edx ;\n"
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#endif
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// xstore-rng
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".byte 0x0f, 0xa7, 0xc0 ;\n"
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"movl %%eax, %0 ;\n"
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: "=g" (m_msr) : "g" (m_buffer.data()), "g" (m_divisor)
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#if (CRYPTOPP_BOOL_X32 || CRYPTOPP_BOOL_X64)
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: "rax", "rdx", "rdi", "cc"
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#else
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: "eax", "edx", "edi", "cc"
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#endif
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);
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const size_t ret = m_msr & 0x1f;
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const size_t rem = STDMIN<size_t>(ret, STDMIN<size_t>(size, 16U /*buffer size*/));
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std::memcpy(output, m_buffer, rem);
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size -= rem; output += rem;
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}
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#elif defined(CRYPTOPP_X86_ASM_AVAILABLE) && defined(_MSC_VER) && defined(_M_IX86)
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while (size)
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{
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word32 result, divisor = m_divisor;
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byte *buffer = reinterpret_cast<byte*>(m_buffer.data());
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__asm {
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mov edi, buffer
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mov edx, divisor
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_emit 0x0f
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_emit 0xa7
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_emit 0xc0
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mov result, eax
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}
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const size_t ret = (m_msr = result) & 0x1f;
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const size_t rem = STDMIN<size_t>(ret, STDMIN<size_t>(size, 16U /*buffer size*/));
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std::memcpy(output, buffer, rem);
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size -= rem; output += rem;
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}
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#else
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throw PadlockRNG_Err("GenerateBlock", "PadlockRNG generator not available");
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#endif // CRYPTOPP_X86_ASM_AVAILABLE
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}
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void PadlockRNG::DiscardBytes(size_t n)
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{
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FixedSizeSecBlock<word32, 4> discard;
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n = RoundUpToMultipleOf(n, sizeof(word32));
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size_t count = STDMIN(n, discard.SizeInBytes());
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while (count)
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{
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GenerateBlock(discard.BytePtr(), count);
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n -= count;
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count = STDMIN(n, discard.SizeInBytes());
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}
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}
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NAMESPACE_END
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