From ea31bbe661abef761e49983b56923e6523b9463a Mon Sep 17 00:00:00 2001
From: aone <info@keka.io>
Date: Thu, 7 Mar 2019 10:06:16 +0100
Subject: [PATCH] Enhanced encryption strength from 7-Zip 19.00

https://github.com/aonez/Keka/issues/379
https://sourceforge.net/p/sevenzip/bugs/2176
---
 .../CPP/7zip/Archive/Wim/WimHandlerOut.cpp    |   2 +-
 Bin/p7zip/source/CPP/7zip/Crypto/7zAes.cpp    |   4 +-
 Bin/p7zip/source/CPP/7zip/Crypto/RandGen.cpp  | 135 ++++++++++++++++--
 Bin/p7zip/source/CPP/7zip/Crypto/RandGen.h    |  19 +++
 Bin/p7zip/source/CPP/7zip/Crypto/WzAes.cpp    |   2 +-
 .../source/CPP/7zip/Crypto/ZipCrypto.cpp      |   2 +-
 6 files changed, 146 insertions(+), 18 deletions(-)

diff --git a/Bin/p7zip/source/CPP/7zip/Archive/Wim/WimHandlerOut.cpp b/Bin/p7zip/source/CPP/7zip/Archive/Wim/WimHandlerOut.cpp
index 1d198df0..39679883 100644
--- a/Bin/p7zip/source/CPP/7zip/Archive/Wim/WimHandlerOut.cpp
+++ b/Bin/p7zip/source/CPP/7zip/Archive/Wim/WimHandlerOut.cpp
@@ -671,7 +671,7 @@ void CHeader::SetDefaultFields(bool useLZX)
     ChunkSize = kChunkSize;
     ChunkSizeBits = kChunkSizeBits;
   }
-  g_RandomGenerator.Generate(Guid, 16);
+  MY_RAND_GEN(Guid, 16);
   PartNumber = 1;
   NumParts = 1;
   NumImages = 1;
diff --git a/Bin/p7zip/source/CPP/7zip/Crypto/7zAes.cpp b/Bin/p7zip/source/CPP/7zip/Crypto/7zAes.cpp
index d33b562a..2ed69bad 100644
--- a/Bin/p7zip/source/CPP/7zip/Crypto/7zAes.cpp
+++ b/Bin/p7zip/source/CPP/7zip/Crypto/7zAes.cpp
@@ -164,8 +164,8 @@ STDMETHODIMP CEncoder::ResetInitVector()
 {
   for (unsigned i = 0; i < sizeof(_iv); i++)
     _iv[i] = 0;
-  _ivSize = 8;
-  g_RandomGenerator.Generate(_iv, _ivSize);
+  _ivSize = 16;
+  MY_RAND_GEN(_iv, _ivSize);
   return S_OK;
 }
 
diff --git a/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.cpp b/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.cpp
index f5ea31f0..a70f4ec8 100644
--- a/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.cpp
+++ b/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.cpp
@@ -2,14 +2,44 @@
 
 #include "StdAfx.h"
 
+#include "RandGen.h"
+
+#ifndef USE_STATIC_SYSTEM_RAND
+
 #ifndef _7ZIP_ST
 #include "../../Windows/Synchronization.h"
 #endif
 
-#include "RandGen.h"
 
-#ifndef _WIN32
+#ifdef _WIN32
+
+#ifdef _WIN64
+#define USE_STATIC_RtlGenRandom
+#endif
+
+#ifdef USE_STATIC_RtlGenRandom
+
+#include <ntsecapi.h>
+
+EXTERN_C_BEGIN
+#ifndef RtlGenRandom
+  #define RtlGenRandom SystemFunction036
+  BOOLEAN WINAPI RtlGenRandom(PVOID RandomBuffer, ULONG RandomBufferLength);
+#endif
+EXTERN_C_END
+
+#else
+EXTERN_C_BEGIN
+typedef BOOLEAN (WINAPI * Func_RtlGenRandom)(PVOID RandomBuffer, ULONG RandomBufferLength);
+EXTERN_C_END
+#endif
+
+
+#else
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #define USE_POSIX_TIME
 #define USE_POSIX_TIME2
 #endif
@@ -21,11 +51,9 @@
 #endif
 #endif
 
-// This is not very good random number generator.
-// Please use it only for salt.
-// First generated data block depends from timer and processID.
+// The seed and first generated data block depend from processID,
+// theadID, timer and system random generator, if available.
 // Other generated data blocks depend from previous state
-// Maybe it's possible to restore original timer value from generated value.
 
 #define HASH_UPD(x) Sha256_Update(&hash, (const Byte *)&x, sizeof(x));
 
@@ -34,25 +62,102 @@ void CRandomGenerator::Init()
   CSha256 hash;
   Sha256_Init(&hash);
 
+  unsigned numIterations = 1000;
+
+  {
+  #ifndef UNDER_CE
+  const unsigned kNumIterations_Small = 100;
+  const unsigned kBufSize = 32;
+  Byte buf[kBufSize];
+  #endif
+
   #ifdef _WIN32
+
   DWORD w = ::GetCurrentProcessId();
   HASH_UPD(w);
   w = ::GetCurrentThreadId();
   HASH_UPD(w);
+
+  #ifdef UNDER_CE
+  /*
+  if (CeGenRandom(kBufSize, buf))
+  {
+    numIterations = kNumIterations_Small;
+    Sha256_Update(&hash, buf, kBufSize);
+  }
+  */
+  #elif defined(USE_STATIC_RtlGenRandom)
+  if (RtlGenRandom(buf, kBufSize))
+  {
+    numIterations = kNumIterations_Small;
+    Sha256_Update(&hash, buf, kBufSize);
+  }
   #else
+  {
+    HMODULE hModule = ::LoadLibrary(TEXT("Advapi32.dll"));
+    if (hModule)
+    {
+      // SystemFunction036() is real name of RtlGenRandom() function
+      Func_RtlGenRandom my_RtlGenRandom = (Func_RtlGenRandom)GetProcAddress(hModule, "SystemFunction036");
+      if (my_RtlGenRandom)
+      {
+        if (my_RtlGenRandom(buf, kBufSize))
+        {
+          numIterations = kNumIterations_Small;
+          Sha256_Update(&hash, buf, kBufSize);
+        }
+      }
+      ::FreeLibrary(hModule);
+    }
+  }
+  #endif
+
+  #else
+  
   pid_t pid = getpid();
   HASH_UPD(pid);
   pid = getppid();
   HASH_UPD(pid);
+
+  {
+    int f = open("/dev/urandom", O_RDONLY);
+    unsigned numBytes = kBufSize;
+    if (f >= 0)
+    {
+      do
+      {
+        int n = read(f, buf, numBytes);
+        if (n <= 0)
+          break;
+        Sha256_Update(&hash, buf, n);
+        numBytes -= n;
+      }
+      while (numBytes);
+      close(f);
+      if (numBytes == 0)
+        numIterations = kNumIterations_Small;
+    }
+  }
+  /*
+  {
+    int n = getrandom(buf, kBufSize, 0);
+    if (n > 0)
+    {
+      Sha256_Update(&hash, buf, n);
+      if (n == kBufSize)
+        numIterations = kNumIterations_Small;
+    }
+  }
+  */
+
+  #endif
+  }
+
+  #ifdef _DEBUG
+  numIterations = 2;
   #endif
 
-  for (unsigned i = 0; i <
-    #ifdef _DEBUG
-    2;
-    #else
-    1000;
-    #endif
-    i++)
+  do
   {
     #ifdef _WIN32
     LARGE_INTEGER v;
@@ -83,6 +188,8 @@ void CRandomGenerator::Init()
       Sha256_Update(&hash, _buff, SHA256_DIGEST_SIZE);
     }
   }
+  while (--numIterations);
+
   Sha256_Final(&hash, _buff);
   _needInit = false;
 }
@@ -120,3 +227,5 @@ void CRandomGenerator::Generate(Byte *data, unsigned size)
 }
 
 CRandomGenerator g_RandomGenerator;
+
+#endif
diff --git a/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.h b/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.h
index cfdcd60d..5122ec4b 100644
--- a/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.h
+++ b/Bin/p7zip/source/CPP/7zip/Crypto/RandGen.h
@@ -5,6 +5,21 @@
 
 #include "../../../C/Sha256.h"
 
+#ifdef _WIN64
+// #define USE_STATIC_SYSTEM_RAND
+#endif
+
+#ifdef USE_STATIC_SYSTEM_RAND
+
+#ifdef _WIN32
+#include <ntsecapi.h>
+#define MY_RAND_GEN(data, size) RtlGenRandom(data, size)
+#else
+#define MY_RAND_GEN(data, size) getrandom(data, size, 0)
+#endif
+
+#else
+
 class CRandomGenerator
 {
   Byte _buff[SHA256_DIGEST_SIZE];
@@ -18,4 +33,8 @@ public:
 
 extern CRandomGenerator g_RandomGenerator;
 
+#define MY_RAND_GEN(data, size) g_RandomGenerator.Generate(data, size)
+
+#endif
+
 #endif
diff --git a/Bin/p7zip/source/CPP/7zip/Crypto/WzAes.cpp b/Bin/p7zip/source/CPP/7zip/Crypto/WzAes.cpp
index 4572f06e..d415ab84 100644
--- a/Bin/p7zip/source/CPP/7zip/Crypto/WzAes.cpp
+++ b/Bin/p7zip/source/CPP/7zip/Crypto/WzAes.cpp
@@ -96,7 +96,7 @@ STDMETHODIMP CBaseCoder::Init()
 HRESULT CEncoder::WriteHeader(ISequentialOutStream *outStream)
 {
   unsigned saltSize = _key.GetSaltSize();
-  g_RandomGenerator.Generate(_key.Salt, saltSize);
+  MY_RAND_GEN(_key.Salt, saltSize);
   Init2();
   RINOK(WriteStream(outStream, _key.Salt, saltSize));
   return WriteStream(outStream, _key.PwdVerifComputed, kPwdVerifSize);
diff --git a/Bin/p7zip/source/CPP/7zip/Crypto/ZipCrypto.cpp b/Bin/p7zip/source/CPP/7zip/Crypto/ZipCrypto.cpp
index ae715063..8610297a 100644
--- a/Bin/p7zip/source/CPP/7zip/Crypto/ZipCrypto.cpp
+++ b/Bin/p7zip/source/CPP/7zip/Crypto/ZipCrypto.cpp
@@ -49,7 +49,7 @@ HRESULT CEncoder::WriteHeader_Check16(ISequentialOutStream *outStream, UInt16 cr
      PKZIP 2.0+ used 1 byte CRC check. It's more secure.
      We also use 1 byte CRC. */
 
-  g_RandomGenerator.Generate(h, kHeaderSize - 1);
+  MY_RAND_GEN(h, kHeaderSize - 1);
   // h[kHeaderSize - 2] = (Byte)(crc);
   h[kHeaderSize - 1] = (Byte)(crc >> 8);
   
-- 
2.17.1