Improved seeding of the random number generator

Fixed AppDir on Windows

git-svn-id: https://svn.code.sf.net/p/keepassx/code/trunk@183 b624d157-de02-0410-bad0-e51aec6abb33

changelog

@@ -11,6 +11,7 @@
 - fixed crash when re-arranging groups (Bug #1754998)
 - fixed size problems of some dialogs
 - files are not longer truncated when saving fails (Bug #1648616)
+- improved seeding of the random number generator
 
 ---------------
     0.3.0a

src/crypto/yarrow.cpp

@@ -26,6 +26,7 @@
 #include <time.h>
 
 #include "yarrow.h"
+#include "random.h"
 
 #ifndef YARROW_DEBUG
 #define YARROW_DEBUG 0
@@ -399,12 +400,15 @@ struct yarrow_source StrongSrc[2];
 void initYarrow(){
 	yarrow256_init(&WeakCtx,2,WeakSrc);
 	yarrow256_init(&StrongCtx,2,StrongSrc);
-	quint8 buffer[100];
-	getRandomBytes(buffer,100);
-	yarrow256_update(&WeakCtx,0,800,100,buffer);
-	getRandomBytes(buffer,100);
-	yarrow256_update(&WeakCtx,1,800,100,buffer);
-	Q_ASSERT(yarrow256_is_seeded(&WeakCtx));
+	new RandomSource();
+}
+
+void yarrowUpdateWeak(unsigned source, unsigned entropy, unsigned length, const quint8 *data){
+	yarrow256_update(&WeakCtx,source,entropy,length,data);
+}
+
+void yarrowUpdateStrong(unsigned source, unsigned entropy, unsigned length, const quint8 *data){
+	yarrow256_update(&StrongCtx,source,entropy,length,data);
 }
 
 void randomize(void* buffer, unsigned int length){

src/crypto/yarrow.h

@@ -182,6 +182,8 @@ do {						\
 		  (src) += (blocksize)) )
 
 void initYarrow();
+void yarrowUpdateWeak(unsigned source, unsigned entropy, unsigned length, const quint8 *data);
+void yarrowUpdateStrong(unsigned source, unsigned entropy, unsigned length, const quint8 *data);
 void randomize(void* buffer, unsigned int length);
 void reseedStrongPool(quint8* buffer1,int l1,quint8* buffer2,int l2);
 

src/keepassx.h

@@ -84,7 +84,6 @@
 #include "crypto/yarrow.h"
 #include "lib/bookmarks.h"
 #include "lib/FileDialogs.h"
-#include "lib/random.h"
 #include "lib/SecString.h"
 #include "lib/tools.h"
 #include "lib/UrlLabel.h"

src/lib/random.cpp

@@ -17,27 +17,49 @@
  *   Free Software Foundation, Inc.,                                       *
  *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.             *
  ***************************************************************************/
-#include <iostream>
-#include <fstream>
+
 #include "random.h"
 
 #if defined(Q_WS_WIN)
-	#include <QSysInfo>
-#include <QMessageBox>
 	#include <windows.h>
+	#include <QSysInfo>
 #endif
 
-using namespace std;
+RandomSource::RandomSource(){
+	quint8 buffer[100];
+	for (int i=0; i<2; i++){
+		getRandomWeak(buffer,100);
+		yarrowUpdateWeak(i,100*8,100,buffer);
+	}
+	
+#ifdef HAS_DEV_RANDOM
+	if (QFile::exists("/dev/random")){
+		DevRandom* devRandom = new DevRandom(this);
+		connect(devRandom, SIGNAL(randomAvailable(int,QByteArray,int)), SLOT(seedStrong(int,QByteArray,int)));
+		connect(devRandom, SIGNAL(finished()), SLOT(deleteLater()));
+		devRandom->start();
+	}
+	else{
+		deleteLater();
+	}
+#else
+	deleteLater();
+#endif
+}
 
-void getRandomBytes(void* buffer,int NumBlocks){
-#if defined(Q_WS_WIN)
+void RandomSource::getRandomWeak(quint8* buffer, int length){
+#if defined(HAS_DEV_RANDOM)
+	QFile dev_urandom("/dev/urandom");
+	if (dev_urandom.open(QIODevice::ReadOnly|QIODevice::Unbuffered) && dev_urandom.read((char*)buffer,length)==length)
+		return;
+#elif defined(Q_WS_WIN)
 	// RtlGenRandom
 	if (QSysInfo::WindowsVersion>=QSysInfo::WV_XP){
 		bool success=false;
 		HMODULE hLib=LoadLibraryA("ADVAPI32.DLL");
 		if (hLib) {
 			BOOLEAN (APIENTRY *pfn)(void*, ULONG) = (BOOLEAN (APIENTRY *)(void*,ULONG))GetProcAddress(hLib,"SystemFunction036");
-			if (pfn && pfn(buffer,NumBlocks)) {
+			if (pfn && pfn(buffer,length)) {
 				success=true;
 			}
 			FreeLibrary(hLib);
@@ -45,18 +67,32 @@ void getRandomBytes(void* buffer,int NumBlocks){
 		if (success)
 			return;
 	}
-#else
-	FILE* dev_random = fopen("/dev/random","r");
-	if (dev_random){
-		size_t bytesRead = fread(buffer,1,NumBlocks,dev_random);
-		fclose(dev_random);
-		if (bytesRead==NumBlocks)
-			return;
-	}
 #endif
 	
 	srand(time(NULL));
-	for(int i=0;i<NumBlocks;i++){
+	for(int i=0;i<length;i++){
 		((quint8*)buffer)[i] = (quint8) (rand()%256);
 	}
 }
+
+#ifdef HAS_DEV_RANDOM
+void RandomSource::seedStrong(int source, QByteArray buffer, int length){
+	yarrowUpdateStrong(source,length*8,length,(const quint8*)buffer.constData());
+}
+
+DevRandom::DevRandom(QObject* parent) : QThread(parent){
+}
+
+void DevRandom::run(){
+	QByteArray buffer(50,0);
+	for (int i=0; i<2; i++){
+		if (getRandomStrong((quint8*)buffer.data(),50))
+			emit randomAvailable(i,buffer,50);
+	}
+}
+
+bool DevRandom::getRandomStrong(quint8* buffer, int length){
+	QFile dev_random("/dev/random");
+	return (dev_random.open(QIODevice::ReadOnly|QIODevice::Unbuffered) && dev_random.read((char*)buffer,length)==length);
+}
+#endif

src/lib/random.h

@@ -20,6 +20,42 @@
 #ifndef RANDOM_H_
 #define RANDOM_H_
 
-extern void getRandomBytes(void* buffer,int NumBlocks);
+#include <QObject>
+
+#if defined(Q_WS_X11) || defined(Q_WS_MAC)
+#define HAS_DEV_RANDOM
+#include <QThread>
+#endif
+
+class RandomSource : public QObject {
+	Q_OBJECT
+	
+	public:
+		RandomSource();
+	
+	private:
+		static void getRandomWeak(quint8* buffer, int length);
+
+#ifdef HAS_DEV_RANDOM
+	private slots:
+		void seedStrong(int source, QByteArray buffer, int length);
+#endif
+};
+
+#ifdef HAS_DEV_RANDOM
+class DevRandom : public QThread {
+	Q_OBJECT
+	
+	public:
+		DevRandom(QObject* parent = 0);
+		void run();
+		
+	signals:
+		void randomAvailable(int source, QByteArray buffer, int length);
+		
+	private:
+		static bool getRandomStrong(quint8* buffer, int length);
+};
+#endif
 
 #endif

src/main_win32.cpp

@@ -23,7 +23,18 @@
 #include "main.h"
 
 void initAppPaths(int argc,char** argv){
-	AppDir = QApplication::applicationDirPath();
+	QFileInfo filePath;
+	QT_WA({
+		wchar_t module_name[256];
+		GetModuleFileNameW(0, module_name, sizeof(module_name) / sizeof(wchar_t));
+		filePath = QString::fromUtf16((ushort *)module_name);
+	}, {
+		char module_name[256];
+		GetModuleFileNameA(0, module_name, sizeof(module_name));
+		filePath = QString::fromLocal8Bit(module_name);
+	});	
+	AppDir = filePath.filePath();
+	AppDir.truncate(AppDir.lastIndexOf("/"));
 	
 	HomeDir = QString::fromLocal8Bit(qgetenv("APPDATA").constData());
 	if(!HomeDir.isEmpty() && QFile::exists(HomeDir))