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152 lines
3.6 KiB
152 lines
3.6 KiB
![]()
4 years ago
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// randpool.cpp - originally written and placed in the public domain by Wei Dai
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// RandomPool used to follow the design of randpool in PGP 2.6.x,
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// but as of version 5.5 it has been redesigned to reduce the risk
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// of reusing random numbers after state rollback (which may occur
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// when running in a virtual machine like VMware).
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#include "pch.h"
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#ifndef CRYPTOPP_IMPORTS
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#include "randpool.h"
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#include "aes.h"
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#include "sha.h"
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#include "hrtimer.h"
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#include "trap.h"
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// OldRandomPool
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#include "mdc.h"
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#include "modes.h"
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#include <time.h>
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NAMESPACE_BEGIN(CryptoPP)
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RandomPool::RandomPool()
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: m_pCipher(new AES::Encryption), m_keySet(false)
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{
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::memset(m_key, 0, m_key.SizeInBytes());
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::memset(m_seed, 0, m_seed.SizeInBytes());
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}
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void RandomPool::IncorporateEntropy(const byte *input, size_t length)
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{
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SHA256 hash;
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hash.Update(m_key, 32);
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hash.Update(input, length);
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hash.Final(m_key);
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m_keySet = false;
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}
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void RandomPool::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
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{
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if (size > 0)
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{
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if (!m_keySet)
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m_pCipher->SetKey(m_key, 32);
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CRYPTOPP_COMPILE_ASSERT(sizeof(TimerWord) <= 16);
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CRYPTOPP_COMPILE_ASSERT(sizeof(time_t) <= 8);
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Timer timer;
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TimerWord tw = timer.GetCurrentTimerValue();
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*(TimerWord *)(void*)m_seed.data() += tw;
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time_t t = time(NULLPTR);
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// UBsan finding: signed integer overflow: 1876017710 + 1446085457 cannot be represented in type 'long int'
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// *(time_t *)(m_seed.data()+8) += t;
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word64 tt1 = 0, tt2 = (word64)t;
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::memcpy(&tt1, m_seed.data()+8, 8);
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::memcpy(m_seed.data()+8, &(tt2 += tt1), 8);
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// Wipe the intermediates
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*((volatile TimerWord*)&tw) = 0;
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*((volatile word64*)&tt1) = 0;
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*((volatile word64*)&tt2) = 0;
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do
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{
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m_pCipher->ProcessBlock(m_seed);
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size_t len = UnsignedMin(16, size);
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target.ChannelPut(channel, m_seed, len);
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size -= len;
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} while (size > 0);
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}
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}
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// OldRandomPool is provided for backwards compatibility for a migration path
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typedef MDC<SHA1> OldRandomPoolCipher;
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OldRandomPool::OldRandomPool(unsigned int poolSize)
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: pool(poolSize), key(OldRandomPoolCipher::DEFAULT_KEYLENGTH), addPos(0), getPos(poolSize)
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{
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CRYPTOPP_ASSERT(poolSize > key.size());
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::memset(pool, 0, poolSize);
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::memset(key, 0, key.size());
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}
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void OldRandomPool::IncorporateEntropy(const byte *input, size_t length)
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{
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size_t t;
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while (length > (t = pool.size() - addPos))
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{
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xorbuf(pool+addPos, input, t);
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input += t;
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length -= t;
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Stir();
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}
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if (length)
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{
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xorbuf(pool+addPos, input, length);
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addPos += length;
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getPos = pool.size(); // Force stir on get
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}
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}
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void OldRandomPool::Stir()
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{
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CFB_Mode<OldRandomPoolCipher>::Encryption cipher;
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for (int i=0; i<2; i++)
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{
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cipher.SetKeyWithIV(key, key.size(), pool.end()-cipher.IVSize());
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cipher.ProcessString(pool, pool.size());
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::memcpy(key, pool, key.size());
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}
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addPos = 0;
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getPos = key.size();
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}
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void OldRandomPool::GenerateIntoBufferedTransformation(BufferedTransformation &target, const std::string &channel, lword size)
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{
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while (size > 0)
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{
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if (getPos == pool.size())
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Stir();
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size_t t = UnsignedMin(pool.size() - getPos, size);
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target.ChannelPut(channel, pool+getPos, t);
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size -= t;
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getPos += t;
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}}
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byte OldRandomPool::GenerateByte()
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{
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if (getPos == pool.size())
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Stir();
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return pool[getPos++];
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}
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void OldRandomPool::GenerateBlock(byte *outString, size_t size)
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{
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ArraySink sink(outString, size);
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GenerateIntoBufferedTransformation(sink, DEFAULT_CHANNEL, size);
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}
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NAMESPACE_END
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#endif
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