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287 lines
9.4 KiB
287 lines
9.4 KiB
![]()
4 years ago
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// strciphr.cpp - originally written and placed in the public domain by Wei Dai
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#include "pch.h"
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#ifndef CRYPTOPP_IMPORTS
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#include "strciphr.h"
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// Squash MS LNK4221 and libtool warnings
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#ifndef CRYPTOPP_MANUALLY_INSTANTIATE_TEMPLATES
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extern const char STRCIPHER_FNAME[] = __FILE__;
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#endif
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NAMESPACE_BEGIN(CryptoPP)
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template <class S>
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void AdditiveCipherTemplate<S>::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms)
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{
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PolicyInterface &policy = this->AccessPolicy();
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policy.CipherSetKey(params, key, length);
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m_leftOver = 0;
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unsigned int bufferByteSize = policy.CanOperateKeystream() ? GetBufferByteSize(policy) : RoundUpToMultipleOf(1024U, GetBufferByteSize(policy));
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m_buffer.New(bufferByteSize);
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if (this->IsResynchronizable())
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{
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size_t ivLength;
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const byte *iv = this->GetIVAndThrowIfInvalid(params, ivLength);
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policy.CipherResynchronize(m_buffer, iv, ivLength);
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}
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}
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template <class S>
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void AdditiveCipherTemplate<S>::GenerateBlock(byte *outString, size_t length)
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{
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if (m_leftOver > 0)
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{
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const size_t len = STDMIN(m_leftOver, length);
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std::memcpy(outString, PtrSub(KeystreamBufferEnd(), m_leftOver), len);
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length -= len; m_leftOver -= len;
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outString = PtrAdd(outString, len);
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if (!length) {return;}
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}
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PolicyInterface &policy = this->AccessPolicy();
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unsigned int bytesPerIteration = policy.GetBytesPerIteration();
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if (length >= bytesPerIteration)
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{
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const size_t iterations = length / bytesPerIteration;
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policy.WriteKeystream(outString, iterations);
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length -= iterations * bytesPerIteration;
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outString = PtrAdd(outString, iterations * bytesPerIteration);
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}
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if (length > 0)
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{
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size_t bufferByteSize = RoundUpToMultipleOf(length, bytesPerIteration);
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size_t bufferIterations = bufferByteSize / bytesPerIteration;
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policy.WriteKeystream(PtrSub(KeystreamBufferEnd(), bufferByteSize), bufferIterations);
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std::memcpy(outString, PtrSub(KeystreamBufferEnd(), bufferByteSize), length);
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m_leftOver = bufferByteSize - length;
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}
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}
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template <class S>
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void AdditiveCipherTemplate<S>::ProcessData(byte *outString, const byte *inString, size_t length)
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{
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if (m_leftOver > 0)
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{
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const size_t len = STDMIN(m_leftOver, length);
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xorbuf(outString, inString, PtrSub(KeystreamBufferEnd(), m_leftOver), len);
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length -= len; m_leftOver -= len;
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inString = PtrAdd(inString, len);
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outString = PtrAdd(outString, len);
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if (!length) {return;}
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}
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PolicyInterface &policy = this->AccessPolicy();
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unsigned int bytesPerIteration = policy.GetBytesPerIteration();
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if (policy.CanOperateKeystream() && length >= bytesPerIteration)
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{
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const size_t iterations = length / bytesPerIteration;
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unsigned int alignment = policy.GetAlignment();
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volatile int inAligned = IsAlignedOn(inString, alignment) << 1;
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volatile int outAligned = IsAlignedOn(outString, alignment) << 0;
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KeystreamOperation operation = KeystreamOperation(inAligned | outAligned);
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policy.OperateKeystream(operation, outString, inString, iterations);
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inString = PtrAdd(inString, iterations * bytesPerIteration);
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outString = PtrAdd(outString, iterations * bytesPerIteration);
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length -= iterations * bytesPerIteration;
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if (!length) {return;}
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}
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size_t bufferByteSize = m_buffer.size();
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size_t bufferIterations = bufferByteSize / bytesPerIteration;
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while (length >= bufferByteSize)
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{
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policy.WriteKeystream(m_buffer, bufferIterations);
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xorbuf(outString, inString, KeystreamBufferBegin(), bufferByteSize);
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length -= bufferByteSize;
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inString = PtrAdd(inString, bufferByteSize);
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outString = PtrAdd(outString, bufferByteSize);
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}
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if (length > 0)
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{
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bufferByteSize = RoundUpToMultipleOf(length, bytesPerIteration);
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bufferIterations = bufferByteSize / bytesPerIteration;
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policy.WriteKeystream(PtrSub(KeystreamBufferEnd(), bufferByteSize), bufferIterations);
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xorbuf(outString, inString, PtrSub(KeystreamBufferEnd(), bufferByteSize), length);
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m_leftOver = bufferByteSize - length;
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}
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}
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template <class S>
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void AdditiveCipherTemplate<S>::Resynchronize(const byte *iv, int length)
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{
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PolicyInterface &policy = this->AccessPolicy();
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m_leftOver = 0;
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m_buffer.New(GetBufferByteSize(policy));
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policy.CipherResynchronize(m_buffer, iv, this->ThrowIfInvalidIVLength(length));
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}
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template <class BASE>
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void AdditiveCipherTemplate<BASE>::Seek(lword position)
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{
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PolicyInterface &policy = this->AccessPolicy();
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word32 bytesPerIteration = policy.GetBytesPerIteration();
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policy.SeekToIteration(position / bytesPerIteration);
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position %= bytesPerIteration;
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if (position > 0)
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{
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policy.WriteKeystream(PtrSub(KeystreamBufferEnd(), bytesPerIteration), 1);
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m_leftOver = bytesPerIteration - static_cast<word32>(position);
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}
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else
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m_leftOver = 0;
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}
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template <class BASE>
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void CFB_CipherTemplate<BASE>::UncheckedSetKey(const byte *key, unsigned int length, const NameValuePairs ¶ms)
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{
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PolicyInterface &policy = this->AccessPolicy();
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policy.CipherSetKey(params, key, length);
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if (this->IsResynchronizable())
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{
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size_t ivLength;
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const byte *iv = this->GetIVAndThrowIfInvalid(params, ivLength);
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policy.CipherResynchronize(iv, ivLength);
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}
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m_leftOver = policy.GetBytesPerIteration();
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}
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template <class BASE>
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void CFB_CipherTemplate<BASE>::Resynchronize(const byte *iv, int length)
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{
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PolicyInterface &policy = this->AccessPolicy();
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policy.CipherResynchronize(iv, this->ThrowIfInvalidIVLength(length));
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m_leftOver = policy.GetBytesPerIteration();
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}
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template <class BASE>
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void CFB_CipherTemplate<BASE>::ProcessData(byte *outString, const byte *inString, size_t length)
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{
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CRYPTOPP_ASSERT(outString); CRYPTOPP_ASSERT(inString);
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CRYPTOPP_ASSERT(length % this->MandatoryBlockSize() == 0);
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PolicyInterface &policy = this->AccessPolicy();
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word32 bytesPerIteration = policy.GetBytesPerIteration();
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byte *reg = policy.GetRegisterBegin();
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if (m_leftOver)
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{
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const size_t len = STDMIN(m_leftOver, length);
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CombineMessageAndShiftRegister(outString, PtrAdd(reg, bytesPerIteration - m_leftOver), inString, len);
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m_leftOver -= len; length -= len;
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inString = PtrAdd(inString, len);
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outString = PtrAdd(outString, len);
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}
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if (!length) {return;}
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// TODO: Figure out what is happening on ARM A-32. x86, Aarch64 and PowerPC are OK.
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// The issue surfaced for CFB mode when we cut-in Cryptogams AES ARMv7 asm.
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// Using 'outString' for both input and output leads to incorrect results.
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//
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// Benchmarking on Cortex-A7 and Cortex-A9 indicates removing the block
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// below costs about 9 cpb for CFB mode on ARM.
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//
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// Also see https://github.com/weidai11/cryptopp/issues/683.
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const unsigned int alignment = policy.GetAlignment();
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volatile bool inAligned = IsAlignedOn(inString, alignment);
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volatile bool outAligned = IsAlignedOn(outString, alignment);
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if (policy.CanIterate() && length >= bytesPerIteration && outAligned)
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{
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CipherDir cipherDir = GetCipherDir(*this);
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if (inAligned)
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policy.Iterate(outString, inString, cipherDir, length / bytesPerIteration);
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else
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{
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// GCC and Clang do not like this on ARM. The incorrect result is a string
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// of 0's instead of ciphertext (or plaintext if decrypting). The 0's trace
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// back to the allocation for the std::string in datatest.cpp. Elements in the
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// string are initialized to their default value, which is 0.
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//
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// It almost feels as if the compiler does not see the string is transformed
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// in-place so it short-circuits the transform. However, if we use a stand-alone
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// reproducer with the same data then the issue is _not_ present.
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//
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// When working on this issue we introduced PtrAdd and PtrSub to ensure we were
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// not running afoul of pointer arithmetic rules of the language. Namely we need
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// to use ptrdiff_t when subtracting pointers. We believe the relevant code paths
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// are clean.
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//
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// One workaround is a distinct and aligned temporary buffer. It [mostly] works
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// as expected but requires an extra allocation (casts not shown):
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//
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// std::string temp(inString, length);
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// policy.Iterate(outString, &temp[0], cipherDir, length / bytesPerIteration);
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std::memcpy(outString, inString, length);
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policy.Iterate(outString, outString, cipherDir, length / bytesPerIteration);
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}
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const size_t remainder = length % bytesPerIteration;
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inString = PtrAdd(inString, length - remainder);
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outString = PtrAdd(outString, length - remainder);
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length = remainder;
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}
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while (length >= bytesPerIteration)
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{
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policy.TransformRegister();
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CombineMessageAndShiftRegister(outString, reg, inString, bytesPerIteration);
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length -= bytesPerIteration;
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inString = PtrAdd(inString, bytesPerIteration);
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outString = PtrAdd(outString, bytesPerIteration);
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}
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if (length > 0)
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{
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policy.TransformRegister();
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CombineMessageAndShiftRegister(outString, reg, inString, length);
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m_leftOver = bytesPerIteration - length;
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}
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}
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template <class BASE>
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void CFB_EncryptionTemplate<BASE>::CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, size_t length)
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{
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xorbuf(reg, message, length);
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std::memcpy(output, reg, length);
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}
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template <class BASE>
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void CFB_DecryptionTemplate<BASE>::CombineMessageAndShiftRegister(byte *output, byte *reg, const byte *message, size_t length)
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{
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for (size_t i=0; i<length; i++)
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{
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byte b = message[i];
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output[i] = reg[i] ^ b;
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reg[i] = b;
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}
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}
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NAMESPACE_END
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#endif
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