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[#3680] Enabled SecurityManager results in ClassNotFoundError during io.netty.util.NetUtil initialization

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Motivation:

When a SecurityManager is in place that preven reading the somaxconn file trying to bootstrap a channel later will result in a ClassNotFoundError.

Modifications:

- Reading the file in a privileged block.

Result:

No more ClassNotFoundError when a SecurityManager is in place.
This commit is contained in:
Norman Maurer 2015-04-23 12:14:49 +02:00
parent f812180c2d
commit f67b14bf35
1 changed files with 36 additions and 27 deletions
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63
common/src/main/java/io/netty/util/NetUtil.java
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@ -29,6 +29,8 @@ import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
@ -231,38 +233,45 @@ public final class NetUtil {
LOOPBACK_IF = loopbackIface;
LOCALHOST = loopbackAddr;
// Determine the default somaxconn (server socket backlog) value of the platform.
// The known defaults:
// - Windows NT Server 4.0+: 200
// - Linux and Mac OS X: 128
int somaxconn = PlatformDependent.isWindows() ? 200 : 128;
File file = new File("/proc/sys/net/core/somaxconn");
if (file.exists()) {
BufferedReader in = null;
try {
in = new BufferedReader(new FileReader(file));
somaxconn = Integer.parseInt(in.readLine());
if (logger.isDebugEnabled()) {
logger.debug("{}: {}", file, somaxconn);
}
} catch (Exception e) {
logger.debug("Failed to get SOMAXCONN from: {}", file, e);
} finally {
if (in != null) {
// As a SecurityManager may prevent reading the somaxconn file we wrap this in a privileged block.
//
// See https://github.com/netty/netty/issues/3680
SOMAXCONN = AccessController.doPrivileged(new PrivilegedAction<Integer>() {
@Override
public Integer run() {
// Determine the default somaxconn (server socket backlog) value of the platform.
// The known defaults:
// - Windows NT Server 4.0+: 200
// - Linux and Mac OS X: 128
int somaxconn = PlatformDependent.isWindows() ? 200 : 128;
File file = new File("/proc/sys/net/core/somaxconn");
if (file.exists()) {
BufferedReader in = null;
try {
in.close();
in = new BufferedReader(new FileReader(file));
somaxconn = Integer.parseInt(in.readLine());
if (logger.isDebugEnabled()) {
logger.debug("{}: {}", file, somaxconn);
}
} catch (Exception e) {
// Ignored.
logger.debug("Failed to get SOMAXCONN from: {}", file, e);
} finally {
if (in != null) {
try {
in.close();
} catch (Exception e) {
// Ignored.
}
}
}
} else {
if (logger.isDebugEnabled()) {
logger.debug("{}: {} (non-existent)", file, somaxconn);
}
}
return somaxconn;
}
} else {
if (logger.isDebugEnabled()) {
logger.debug("{}: {} (non-existent)", file, somaxconn);
}
}
SOMAXCONN = somaxconn;
});
}
/**