Use system property to detect if root is running the program
Motivation: We forked a new process to detect if the program is run by root. We should better just use user.name system property Modifications: - Change PlatformDependent.isRoot0() to read the user.name system property to detect if root runs the program and rename it to maybeSuperUser0(). - Rename PlatformDependent.isRoot() to maybeSuperUser() and let it init directly in the static block Result: Less heavy way to detect if the program is run by root.
This commit is contained in:
Norman Maurer
parent
b32f3777ea
commit
242c040038
@ -15,7 +15,6 @@
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*/
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package io.netty.util.internal;
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import io.netty.util.CharsetUtil;
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import io.netty.util.internal.logging.InternalLogger;
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import io.netty.util.internal.logging.InternalLoggerFactory;
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import org.jctools.queues.MpscArrayQueue;
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@ -27,13 +26,8 @@ import org.jctools.queues.atomic.SpscLinkedAtomicQueue;
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import org.jctools.util.Pow2;
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import org.jctools.util.UnsafeAccess;
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import java.io.BufferedReader;
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import java.io.File;
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import java.io.IOException;
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import java.io.InputStreamReader;
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import java.lang.reflect.Method;
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import java.net.InetSocketAddress;
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import java.net.ServerSocket;
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import java.nio.ByteBuffer;
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import java.nio.ByteOrder;
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import java.security.AccessController;
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@ -73,7 +67,7 @@ public final class PlatformDependent {
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private static final boolean IS_ANDROID = isAndroid0();
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private static final boolean IS_WINDOWS = isWindows0();
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private static volatile Boolean IS_ROOT;
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private static final boolean MAYBE_SUPER_USER;
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private static final int JAVA_VERSION = javaVersion0();
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@ -157,6 +151,8 @@ public final class PlatformDependent {
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}
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DIRECT_MEMORY_LIMIT = maxDirectMemory;
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logger.debug("io.netty.maxDirectMemory: {} bytes", maxDirectMemory);
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MAYBE_SUPER_USER = maybeSuperUser0();
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}
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/**
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@ -174,18 +170,11 @@ public final class PlatformDependent {
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}
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/**
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* Return {@code true} if the current user is root. Note that this method returns
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* {@code false} if on Windows.
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* Return {@code true} if the current user may be a super-user. Be aware that this is just an hint and so it may
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* return false-positives.
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*/
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public static boolean isRoot() {
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if (IS_ROOT == null) {
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synchronized (PlatformDependent.class) {
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if (IS_ROOT == null) {
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IS_ROOT = isRoot0();
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}
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}
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}
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return IS_ROOT;
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public static boolean maybeSuperUser() {
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return MAYBE_SUPER_USER;
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}
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/**
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@ -652,97 +641,13 @@ public final class PlatformDependent {
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return windows;
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}
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private static boolean isRoot0() {
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private static boolean maybeSuperUser0() {
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String username = SystemPropertyUtil.get("user.name");
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if (isWindows()) {
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return false;
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return "Administrator".equals(username);
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}
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String[] ID_COMMANDS = { "/usr/bin/id", "/bin/id", "/usr/xpg4/bin/id", "id"};
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Pattern UID_PATTERN = Pattern.compile("^(?:0|[1-9][0-9]*)$");
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for (String idCmd: ID_COMMANDS) {
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Process p = null;
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BufferedReader in = null;
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String uid = null;
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try {
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p = Runtime.getRuntime().exec(new String[] { idCmd, "-u" });
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in = new BufferedReader(new InputStreamReader(p.getInputStream(), CharsetUtil.US_ASCII));
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uid = in.readLine();
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in.close();
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for (;;) {
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try {
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int exitCode = p.waitFor();
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if (exitCode != 0) {
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uid = null;
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}
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break;
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} catch (InterruptedException e) {
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// Ignore
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}
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}
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} catch (Throwable ignored) {
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// Failed to run the command.
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uid = null;
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} finally {
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if (in != null) {
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try {
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in.close();
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} catch (IOException e) {
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// Ignore
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}
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}
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if (p != null) {
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try {
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p.destroy();
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} catch (Exception e) {
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// Android sometimes triggers an ErrnoException.
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}
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}
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}
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if (uid != null && UID_PATTERN.matcher(uid).matches()) {
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logger.debug("UID: {}", uid);
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return "0".equals(uid);
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}
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}
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logger.debug("Could not determine the current UID using /usr/bin/id; attempting to bind at privileged ports.");
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Pattern PERMISSION_DENIED = Pattern.compile(".*(?:denied|not.*permitted).*");
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for (int i = 1023; i > 0; i --) {
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ServerSocket ss = null;
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try {
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ss = new ServerSocket();
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ss.setReuseAddress(true);
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ss.bind(new InetSocketAddress(i));
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if (logger.isDebugEnabled()) {
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logger.debug("UID: 0 (succeded to bind at port {})", i);
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}
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return true;
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} catch (Exception e) {
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// Failed to bind.
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// Check the error message so that we don't always need to bind 1023 times.
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String message = e.getMessage();
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if (message == null) {
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message = "";
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}
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message = message.toLowerCase();
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if (PERMISSION_DENIED.matcher(message).matches()) {
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break;
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}
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} finally {
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if (ss != null) {
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try {
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ss.close();
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} catch (Exception e) {
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// Ignore.
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}
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}
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}
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}
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logger.debug("UID: non-root (failed to bind at any privileged ports)");
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return false;
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// Check for root and toor as some BSDs have a toor user that is basically the same as root.
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return "root".equals(username) || "toor".equals(username);
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}
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private static int javaVersion0() {
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@ -486,7 +486,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
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if (Boolean.TRUE.equals(config().getOption(ChannelOption.SO_BROADCAST)) &&
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localAddress instanceof InetSocketAddress &&
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!((InetSocketAddress) localAddress).getAddress().isAnyLocalAddress() &&
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!PlatformDependent.isWindows() && !PlatformDependent.isRoot()) {
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!PlatformDependent.isWindows() && !PlatformDependent.maybeSuperUser()) {
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// Warn a user about the fact that a non-root user can't receive a
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// broadcast packet on *nix if the socket is bound on non-wildcard address.
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logger.warn(
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@ -158,7 +158,7 @@ public class DefaultDatagramChannelConfig extends DefaultChannelConfig implement
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// See: https://github.com/netty/netty/issues/576
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if (broadcast &&
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!javaSocket.getLocalAddress().isAnyLocalAddress() &&
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!PlatformDependent.isWindows() && !PlatformDependent.isRoot()) {
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!PlatformDependent.isWindows() && !PlatformDependent.maybeSuperUser()) {
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// Warn a user about the fact that a non-root user can't receive a
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// broadcast packet on *nix if the socket is bound on non-wildcard address.
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logger.warn(
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