[Solved]Using QCA results in segmentation fault
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Im trying to get QCA (Qt Cryptographic Arcetecture) to work on Qt 5.0 on Ubuntu 13.04 32bit. But when I build the program I get a Segmentation fault as soon as the function that uses QCA is called.
I installed openssl, libqca-dev, and qca-plugin for openssl from the ubuntu repos.
I copied qca-plugin for openssl and pasted it in my project's directory inside a folder named crypto
I added include path and LIBS to my pro file:Here is my project.pro file
@folder_01.source = qml/umail
folder_01.target = qml
DEPLOYMENTFOLDERS = folder_01Additional import path used to resolve QML modules in Creator's code model
QML_IMPORT_PATH =
If your application uses the Qt Mobility libraries, uncomment the following
lines and add the respective components to the MOBILITY variable.
CONFIG += mobility
MOBILITY +=
The .cpp file which was generated for your project. Feel free to hack it.
SOURCES += main.cpp
sendmail.cpp
receivemail.cpp
cryptohash.cppInstallation path
target.path =
Please do not modify the following two lines. Required for deployment.
include(qtquick2applicationviewer/qtquick2applicationviewer.pri)
qtcAddDeployment()HEADERS +=
sendmail.h
receivemail.h
cryptohash.hOTHER_FILES +=
crypto/libqca-ossl.soINCLUDEPATH += /usr/include/QtCrypto
LIBS += -L$$PWD/usr/lib/i386-linux-gnu -lqca
@Here is the function which causes the segmentation fault(It is a method of CryptoHash class):
@void CryptoHash::encryptSomeData()
{
/**************************************************************
*
*
* I get segmentation fault at
* QCA::Initializer init = QCA::Initializer();
*
*
**************************************************************/
//initialize QCA
QCA::Initializer init = QCA::Initializer();
//generate a random symmetric 16-bytes key
QCA::SymmetricKey key = QCA::SymmetricKey(16);
//generate a random 16-bytes initialization vector
QCA::InitializationVector iv = QCA::InitializationVector(16);
//initialize the cipher for aes128 algorithm, using CBC mode,
//with padding enabled (by default), in encoding mode,
//using the given key and initialization vector
QCA::Cipher cipher = QCA::Cipher(QString("aes128"), QCA::Cipher::CBC,
QCA::Cipher::DefaultPadding, QCA::Encode,
key, iv);
//check if aes128 is available
if (!QCA::isSupported("aes128-cbc-pkcs7"))
{
qDebug() << "AES128 CBC PKCS7 not supported - "
"please check if qca-ossl plugin"
"installed correctly !";
return;
}
//the string we want to encrypt
QString s = "Hello, world !";
//we use SecureArray: read more here:
//QCA secure array details
QCA::SecureArray secureData = s.toLatin1();
//we encrypt the data
QCA::SecureArray encryptedData = cipher.process(secureData);
//check if encryption succeded
if (!cipher.ok())
{
qDebug() << "Encryption failed !";
return;
}
//display the result
qDebug() << QString(qPrintable(QCA::arrayToHex(encryptedData.toByteArray())));
//set the cipher mode to encryption
cipher.setup(QCA::Decode, key, iv);
//decrypt the encrypted data
QCA::SecureArray decryptedData = cipher.process(encryptedData);
//check if decryption succeded
if (!cipher.ok())
{
qDebug() << "Decryption failed !";
return;
}
//display the decrypted data (it should be "Hello, world !")
qDebug() << QString(decryptedData.data());
}
@Please help me figure out what is wrong. My whole project depends on cryptography. BTW Im a cryptography noob.
Thank you....
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Hi and welcome to devnet,
After a quick read of an example:
change
@QCA::Initializer init = QCA::Initializer();@
by
@QCA::Initializer init;@
Hope it helps
-
Thank you for the quick reply... however I tried
@QCA::Initializer init;@
And even
@QCA::Initializer * init = new QCA::Initializer();@
But the same erroe is happening.Another interesting thing is that even if I remove the
@LIBS += -L$$PWD/usr/lib/i386-linux-gnu -lqca@
from the .pro file the same thing is happening. Does this mean that the library is not loading? -
Another thing, are you sure that all libraries are found when you start your program ?
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This is the compiler output
@03:02:29: Running steps for project umail...
03:02:29: Starting: "/usr/bin/qmake" '/home/kaziwaseef/QML/Ubuntu Phone App/umail/umail/umail.pro' -r -spec linux-g++ CONFIG+=debug CONFIG+=declarative_debug CONFIG+=qml_debug
03:02:29: The process "/usr/bin/qmake" exited normally.
03:02:29: Starting: "/usr/bin/make"
Copying application data...
03:02:29: The process "/usr/bin/make" exited normally.
03:02:29: Elapsed time: 00:00.@Everything seems to compile ok.... any other tests that I can perform???
Thank you.
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Not the compilation, the application itself, check that it can find all libraries when starting (not the same as when linking) i.e using ldd
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Errr... could you please tell me how to do that?
- This is the first time I'm manually linking to external libraries...
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run ldd youApplicationExecutable and look at the output for missing libraries
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Thank you for the help. This is the output of ldd. Line 2 shows that libqca loads but I was expecting libqca.so.2.0.3
@linux-gate.so.1 => (0xb7729000)
libqca.so.2 => /usr/lib/i386-linux-gnu/libqca.so.2 (0xb7613000)
libQt5Quick.so.5 => /usr/lib/i386-linux-gnu/libQt5Quick.so.5 (0xb72d9000)
libQt5Qml.so.5 => /usr/lib/i386-linux-gnu/libQt5Qml.so.5 (0xb7099000)
libQt5Network.so.5 => /usr/lib/i386-linux-gnu/libQt5Network.so.5 (0xb6f5d000)
libQt5Gui.so.5 => /usr/lib/i386-linux-gnu/libQt5Gui.so.5 (0xb6b7f000)
libQt5Core.so.5 => /usr/lib/i386-linux-gnu/libQt5Core.so.5 (0xb674b000)
libstdc++.so.6 => /usr/lib/i386-linux-gnu/libstdc++.so.6 (0xb6662000)
libgcc_s.so.1 => /lib/i386-linux-gnu/libgcc_s.so.1 (0xb6644000)
libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xb6491000)
libQtCore.so.4 => /usr/lib/i386-linux-gnu/libQtCore.so.4 (0xb61a9000)
libpthread.so.0 => /lib/i386-linux-gnu/libpthread.so.0 (0xb618e000)
libQt5V8.so.5 => /usr/lib/i386-linux-gnu/libQt5V8.so.5 (0xb5d71000)
libGL.so.1 => /usr/lib/nvidia-313-updates/libGL.so.1 (0xb5c90000)
libm.so.6 => /lib/i386-linux-gnu/libm.so.6 (0xb5c4d000)
libz.so.1 => /lib/i386-linux-gnu/libz.so.1 (0xb5c34000)
libpng12.so.0 => /lib/i386-linux-gnu/libpng12.so.0 (0xb5c0b000)
libicui18n.so.48 => /usr/lib/i386-linux-gnu/libicui18n.so.48 (0xb5a37000)
libicuuc.so.48 => /usr/lib/i386-linux-gnu/libicuuc.so.48 (0xb58d1000)
libdl.so.2 => /lib/i386-linux-gnu/libdl.so.2 (0xb58cc000)
libglib-2.0.so.0 => /lib/i386-linux-gnu/libglib-2.0.so.0 (0xb57cb000)
librt.so.1 => /lib/i386-linux-gnu/librt.so.1 (0xb57c2000)
/lib/ld-linux.so.2 (0xb772a000)
libnvidia-tls.so.313.30 => /usr/lib/nvidia-313-updates/tls/libnvidia-tls.so.313.30 (0xb57be000)
libnvidia-glcore.so.313.30 => /usr/lib/nvidia-313-updates/libnvidia-glcore.so.313.30 (0xb3a7b000)
libX11.so.6 => /usr/lib/i386-linux-gnu/libX11.so.6 (0xb3944000)
libXext.so.6 => /usr/lib/i386-linux-gnu/libXext.so.6 (0xb3932000)
libicudata.so.48 => /usr/lib/i386-linux-gnu/libicudata.so.48 (0xb27c1000)
libpcre.so.3 => /lib/i386-linux-gnu/libpcre.so.3 (0xb2780000)
libxcb.so.1 => /usr/lib/i386-linux-gnu/libxcb.so.1 (0xb275d000)
libXau.so.6 => /usr/lib/i386-linux-gnu/libXau.so.6 (0xb2759000)
libXdmcp.so.6 => /usr/lib/i386-linux-gnu/libXdmcp.so.6 (0xb2752000)@ -
I really dont know what is wrong. Will try to fix it if I I have time... In the meantime I got crypto++ working so I'll use that :)
However, I wish to find out what went wrong with QCA, for knowledge's sake...
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Haaaaaaaaaaaaaaa ! I've forgot that you where using Qt 5...
Then the answer is simple:
You are building your software using Qt 5 and you are linking to your system's qca which is built with Qt 4 so what you get is a binary that will load Qt 5 and Qt 4 in the same address space so they will collide and then the crash.If you take a closer look at ldd's output (i.e using | grep libQt) you'll see this:
libQt5Quick.so.5
libQt5Gui.so.5
libQt5Core.so.5
libQtCore.so.4 <- There's the clue
libQt5V8.so.5So you have two solutions:
build your own qca with your Qt 5 and use that one
build your software with Qt 4
Hope it shed some lights :)
