加固你的TOMCAT，让TOMCAT在chroot的环境下运行

众所周知，chroot下linux系统的一个安全机制，chroot是linux内核的一个系统调用，通过它，可以设定应用软件的运行环境，让应用软件运行在一个特定目录下，这样，即使应用软件有安全漏洞，被入侵，入侵者也被限制在一个特定的目录，从面限制了入侵者的破坏范围。加固了系统的安全性。本文以tomcat为例，详细记录了tomcat以chroot的方式运行的配置过程，也记录配置过程中的出错及排错方法。

环境及工具：系统64位的CentOS6.4、dk为jdk-7u45-linux-x64.tar.gz、apache-tomcat-6.0.41.tar.gz

一、配置java chroot环境

1、先配置jdk，这次配置使用的是 jdk-7u45-linux-x64.tar.gz

tar zxvf jdk-7u45-linux-x64.tar.gz

mkdir /usr/java

cp -a jdk1.7.0_45 /usr/java/

[root@2core local]# /usr/java/jdk1.7.0_45/bin/java -version

java version "1.7.0_45"

Java(TM) SE Runtime Environment (build 1.7.0_45-b18)

Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode)

jdk可以正常启动

2、配置jdk chroot

我选算了 /chroot为 tomcat的根目录

#D=/chroot

#mkdir -p $D

#cd $D

mkdir -p lib lib64 etc tmp dev usr

chmod 755 etc dev usr

chmod 1777 tmp

cp -a /etc/hosts etc/hosts

为了chroot的环境更接近实际的系统根目录，还需要一个特殊的目录，如果无这些目录，将来可能会报错

mkdir -p /chroot/dev/pts

cd /dev

./MAKEDEV -d /chroot/dev null radom urandom zero loop* log console

cp MAKEDEV /chroot/dev

cp -a /dev/shm /chroot/dev

[root@2core local]# ldd /usr/java/jdk1.7.0_45/bin/java

linux-vdso.so.1 => (0x00007fffeafd0000)

libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f3a58efd000)

libjli.so => /usr/java/jdk1.7.0_45/bin/../lib/amd64/jli/libjli.so (0x00007f3a58ce5000)

libdl.so.2 => /lib64/libdl.so.2 (0x00007f3a58ae1000)

libc.so.6 => /lib64/libc.so.6 (0x00007f3a5874e000)

/lib64/ld-linux-x86-64.so.2 (0x00007f3a59123000)

把上面几个库文件复制到/chroot/lib64/目录下

[root@2core local]# ls /chroot/lib64/

ld-linux-x86-64.so.2 libc.so.6 libdl.so.2 libpthread.so.0

[root@2core local]# rm -rf /chroot/usr/java/

[root@2core local]# mkdir /chroot/usr/java

[root@2core local]# cp -a /usr/java/jdk1.7.0_45 /chroot/usr/java/

[root@2core local]# ls /chroot/usr/java/

jdk1.7.0_45

以chroot方式运行java,

[root@2core local]# chroot /chroot /usr/java/jdk1.7.0_45/bin/java

/usr/java/jdk1.7.0_45/bin/java: error while loading shared libraries: libjli.so: cannot open shared object file: No such file or directory

有报错，根据错误可以是缺少相应的库文件，只要把这些文件复制过来就OK了

[root@2core local]# find / -name libjli.so

/usr/java/jdk1.7.0_45/jre/lib/amd64/jli/libjli.so

/usr/java/jdk1.7.0_45/lib/amd64/jli/libjli.so

/usr/local/jdk1.7.0_45/jre/lib/amd64/jli/libjli.so

/usr/local/jdk1.7.0_45/lib/amd64/jli/libjli.so

/chroot/usr/java/jdk1.7.0_45/jre/lib/amd64/jli/libjli.so

/chroot/usr/java/jdk1.7.0_45/lib/amd64/jli/libjli.so

[root@2core local]# cp /chroot/usr/java/jdk1.7.0_45/lib/amd64/jli/libjli.so /chroot/lib64/

[root@2core local]# chroot /chroot /usr/java/jdk1.7.0_45/bin/java -version

Error: dl failure on line 863

Error: failed /usr/java/jdk1.7.0_45/jre/lib/amd64/server/libjvm.so, because libm.so.6: cannot open shared object file: No such file or directory

[root@2core local]#

[root@2core local]#

[root@2core local]# find / -name libm.so.6

/lib64/libm.so.6

[root@2core local]# cp /lib64/libm.so.6 /chroot/lib64/

[root@2core local]# chroot /chroot /usr/java/jdk1.7.0_45/bin/java -version

Java HotSpot(TM) 64-Bit Server VM warning: Can't detect initial thread stack location - find_vma failed

java version "1.7.0_45"

Java(TM) SE Runtime Environment (build 1.7.0_45-b18)

Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode)

这样，可以正常启动java了，但还是有一个警告信息，这是因为jave检测不到相关进程引起的，而linux系统的进程信息是存放在/proc这个目录的，因些，我们还要在/chroot下挂载这个特殊的目录，方法如下

[root@2core local]# mkdir /chroot/proc

[root@2core local]# mount -t proc proc /chroot/proc

[root@2core local]# chroot /chroot /usr/java/jdk1.7.0_45/bin/java -version

java version "1.7.0_45"

Java(TM) SE Runtime Environment (build 1.7.0_45-b18)

Java HotSpot(TM) 64-Bit Server VM (build 24.45-b08, mixed mode)

至此，jdk才算完成配置，这时，让我们查看一下启动JDK需要用到下面几个库，需要注意的是，库文件的位置及名字有可能在不同的版本系统中有差别，但一般都可以根据相关的报错信息，找到相应库文件，并复制过来就OK了

[root@2core local]# ls /chroot/lib64/

ld-linux-x86-64.so.2 libc.so.6 libdl.so.2 libjli.so libm.so.6 libpthread.so.0

二、以下开始配置tomcat了，把tomcat将在/chroot/usr/local这个目录下运行

[root@2core local]# mkdir /chroot/usr/local

[root@2core local]# mv apache-tomcat-6.0.41-src /chroot/usr/local/tomcat

[root@2core local]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

chroot: failed to run command `/usr/local/tomcat/bin/catalina.sh': Permission denied

[root@2core local]# ls /chroot/usr/local/tomcat/bin/catalina.sh -al

-rw-r--r--. 1 root root 17717 5月 19 18:51 /chroot/usr/local/tomcat/bin/catalina.sh

[root@2core local]# chmod 755 /chroot/usr/local

[root@2core local]# chmod 755 /chroot/usr/local/tomcat/bin/*.sh

[root@2core local]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

chroot: failed to run command `/usr/local/tomcat/bin/catalina.sh': No such file or directory

再次[root@2core local]# strace chroot /chroot /usr/local/tomcat/bin/catalina.sh start

留意末部信息

execve("/usr/local/tomcat/bin/catalina.sh", ["/usr/local/tomcat/bin/catalina.s"..., "start"], [/* 25 vars */]) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/locale.alias", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh_CN.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh_CN.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh_CN/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh.UTF-8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh.utf8/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh/LC_MESSAGES/coreutils.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

write(2, "chroot: ", 8chroot: ) = 8

write(2, "failed to run command `/usr/loca"..., 57failed to run command `/usr/local/tomcat/bin/catalina.sh') = 57

open("/usr/share/locale/zh_CN.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh_CN.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh_CN/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh.UTF-8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh.utf8/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/usr/share/locale/zh/LC_MESSAGES/libc.mo", O_RDONLY) = -1 ENOENT (No such file or directory)

write(2, ": No such file or directory", 27: No such file or directory) = 27

write(2, "\n", 1

) = 1

close(1) = 0

close(2) = 0

exit_group(127) = ?

因为启动tomcat的是一个shell的脚本，因此，在chroot里还需要一个运行bash shell的环境

[root@2core local]# cd /chroot/

[root@2core chroot]# mkdir -p bin

[root@2core chroot]# cp /bin/bash bin/

[root@2core chroot]# ln -s /bin/bash bin/sh

[root@2core chroot]# cd lib64

[root@2core lib64]# pwd

/chroot/lib64

[root@2core lib64]# ldd /bin/bash

linux-vdso.so.1 => (0x00007fff2536e000)

libtinfo.so.5 => /lib64/libtinfo.so.5 (0x00007f0c47bb5000)

libdl.so.2 => /lib64/libdl.so.2 (0x00007f0c479b1000)

libc.so.6 => /lib64/libc.so.6 (0x00007f0c4761d000)

/lib64/ld-linux-x86-64.so.2 (0x00007f0c47ddf000)

[root@2core lib64]# cp /lib64/libtinfo.so.5 /chroot/lib64/

[root@2core lib64]# cp /lib64/libdl.so.2 /chroot/lib64/

cp：是否覆盖"/chroot/lib64/libdl.so.2"？ n

[root@2core lib64]# cp /lib64/libc.so.6 /chroot/lib64/

cp：是否覆盖"/chroot/lib64/libc.so.6"？ n

[root@2core lib64]# cp /lib64/ld-linux-x86-64.so.2 /chroot/lib64/

cp：是否覆盖"/chroot/lib64/ld-linux-x86-64.so.2"？ n

测试 bash是否可以在chroot下正常运行,由于这前已经复制部分的库，所以会提示是否覆盖

[root@2core lib64]# chroot /chroot /bin/bash

bash-4.1# pwd

/

注意，这时的bash shell提示符已经改变了，这说明已经可以在chroot下正常启动bash了

bash-4.1# ls

bash: ls: command not found

bash-4.1# exit

exit

[root@2core lib64]#

再次启动tomcat,报错的内容已经不一样了，报错的内容很详细，就是有几个命令找不到，那么，我们把这些命令及相应的库复制到chroot的相应目录即可

[root@2core lib64]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

/usr/local/tomcat/bin/catalina.sh: line 89: uname: command not found

/usr/local/tomcat/bin/catalina.sh: line 109: dirname: command not found

Cannot find //bin/setclasspath.sh

This file is needed to run this program

[root@2core lib64]#

[root@2core lib64]# cp /bin/uname /chroot/bin/

[root@2core lib64]# mkdir - /chroot/usr/bin

[root@2core lib64]# cp /usr/bin/dirname /chroot/usr/bin/

[root@2core lib64]# ldd /bin/uname

linux-vdso.so.1 => (0x00007fff4b5ff000)

libc.so.6 => /lib64/libc.so.6 (0x00007fcfde5b8000)

/lib64/ld-linux-x86-64.so.2 (0x00007fcfde954000)

[root@2core lib64]# ldd /usr/bin/dirname

linux-vdso.so.1 => (0x00007fffb93ea000)

libc.so.6 => /lib64/libc.so.6 (0x00007f8ad0266000)

/lib64/ld-linux-x86-64.so.2 (0x00007f8ad0602000)

[root@2core lib64]# ls /chroot/lib64

- ld-linux-x86-64.so.2 libc.so.6 libdl.so.2 libjli.so libm.so.6 libpthread.so.0 libtinfo.so.5

相关的库之前已经复制了，所以，这里就不需要再复制，再次运行comcat

[root@2core lib64]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

Neither the JAVA_HOME nor the JRE_HOME environment variable is defined

At least one of these environment variable is needed to run this program

[root@2core lib64]#

这次报错的是环境变量的问题，把变量加进去限可，我们先看看catalina.sh这个文件，里面调用了setclasspath.sh 而报错的内容便在setclasspath.sh脚本里。因此，我在setclasspath.sh设置JAVA_HOME变量

[root@2core bin]# vi /chroot/usr/local/tomcat/bin/setclasspath.sh

# Make sure prerequisite environment variables are set

export JAVA_HOME=/usr/java/jdk1.7.0_45

export JRE_HOME=/usr/java/jdk1.7.0_45/jre

if [ -z "$JAVA_HOME" -a -z "$JRE_HOME" ]; then

  if $darwin; then

    # Bugzilla 54390

    if [ -x '/usr/libexec/java_home' ] ; then

      export JAVA_HOME=`/usr/libexec/java_home`

    # Bugzilla 37284 (reviewed).

    elif [ -d "/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home" ]; then

      export JAVA_HOME="/System/Library/Frameworks/JavaVM.framework/Versions/CurrentJDK/Home"

    fi

  else

    JAVA_PATH=`which java 2>/dev/null`

    if [ "x$JAVA_PATH" != "x" ]; then

      JAVA_PATH=`dirname $JAVA_PATH 2>/dev/null`

      JRE_HOME=`dirname $JAVA_PATH 2>/dev/null`

    fi

    if [ "x$JRE_HOME" = "x" ]; then

      # XXX: Should we try other locations?

      if [ -x /usr/bin/java ]; then

        JRE_HOME=/usr

      fi

    fi

  fi

  if [ -z "$JAVA_HOME" -a -z "$JRE_HOME" ]; then

    echo "Neither the JAVA_HOME nor the JRE_HOME environment variable is defined"

    echo "At least one of these environment variable is needed to run this program"

    exit 1

  fi

fi

"setclasspath.sh" 119L, 4252C written

再次运行，还是出错，但已经接近成功了，

[root@2core bin]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

/usr/local/tomcat/bin/catalina.sh: line 193: tty: command not found

Using CATALINA_BASE: /usr/local/tomcat

Using CATALINA_HOME: /usr/local/tomcat

Using CATALINA_TMPDIR: /usr/local/tomcat/temp

Using JRE_HOME: /usr/java/jdk1.7.0_45/jre

Using CLASSPATH: /usr/local/tomcat/bin/bootstrap.jar

/usr/local/tomcat/bin/catalina.sh: line 354: touch: command not found

/usr/local/tomcat/bin/catalina.sh: line 371: /usr/local/tomcat/logs/catalina.out: No such file or directory

报错还是由相关系统命令调用及文件权限的引用的，打它复制过来

[root@2core bin]# cp /bin/touch /chroot/bin/

[root@2core bin]# ldd /bin/touch

linux-vdso.so.1 => (0x00007fff9343f000)

librt.so.1 => /lib64/librt.so.1 (0x00007fbd55ccc000)

libc.so.6 => /lib64/libc.so.6 (0x00007fbd55939000)

libpthread.so.0 => /lib64/libpthread.so.0 (0x00007fbd5571b000)

/lib64/ld-linux-x86-64.so.2 (0x00007fbd55edd000)

[root@2core bin]# cp /lib64/librt.so.1 /chroot/lib64/

[root@2core bin]# mkdir /chroot/usr/local/tomcat/logs

[root@2core bin]# chmod 666 /chroot/usr/local/tomcat/logs

[root@2core bin]#

[root@2core bin]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

/usr/local/tomcat/bin/catalina.sh: line 193: tty: command not found

Using CATALINA_BASE: /usr/local/tomcat

Using CATALINA_HOME: /usr/local/tomcat

Using CATALINA_TMPDIR: /usr/local/tomcat/temp

Using JRE_HOME: /usr/java/jdk1.7.0_45/jre

Using CLASSPATH: /usr/local/tomcat/bin/bootstrap.jar

把tty这个程序复制过来

[root@2core bin]# cp /usr/bin/tty /chroot/usr/bin/

[root@2core bin]# ldd /usr/bin/tty

linux-vdso.so.1 => (0x00007fff1f5ff000)

libc.so.6 => /lib64/libc.so.6 (0x00007f82f2cd9000)

/lib64/ld-linux-x86-64.so.2 (0x00007f82f3075000)

[root@2core bin]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

Using CATALINA_BASE: /usr/local/tomcat

Using CATALINA_HOME: /usr/local/tomcat

Using CATALINA_TMPDIR: /usr/local/tomcat/temp

Using JRE_HOME: /usr/java/jdk1.7.0_45/jre

Using CLASSPATH: /usr/local/tomcat/bin/bootstrap.jar

终于无报错了，大功造成了？怎么回事，java 进程还是起不来

[root@2core bin]# ps auxf|grep java

root 1449 0.0 0.0 103240 852 pts/1 S+ 11:46 0:00 \_ grep java

查看下了上tomcat的日志

[root@2core local]# more /chroot/usr/local/tomcat/logs/catalina.out

Error: Could not find or load main class org.apache.catalina.startup.Bootstrap

[root@2core local]# ls /chroot/usr/local/tomcat/bin/bootstrap.jar

ls: 无法访问/chroot/usr/local/tomcat/bin/bootstrap.jar: 没有那个文件或目录

原来是这个包缺少一个文件

重新从官方网站下载了一个完整的包，解压

 #wget http://mirror.bit.edu.cn/apache/tomcat/tomcat-6/v6.0.41/bin/apache-tomcat-6.0.41.tar.gz

[root@2core local]# cd /chroot/usr/local/

[root@2core local]# ls

tomcat

[root@2core local]# mv tomcat tomcat.bak

[root@2core local]# mv /usr/local/apache-tomcat-6.0.41 ./tomcat

并在/chroot/usr/local/tomcat/bin/setclasspath.sh加入环境变量

[root@2core bin]# vi /chroot/usr/local/tomcat/bin/setclasspath.sh

# Make sure prerequisite environment variables are set

export JAVA_HOME=/usr/java/jdk1.7.0_45

export JRE_HOME=/usr/java/jdk1.7.0_45/jre

再次运行

[root@2core local]# chroot /chroot /usr/local/tomcat/bin/catalina.sh start

Using CATALINA_BASE: /usr/local/tomcat

Using CATALINA_HOME: /usr/local/tomcat

Using CATALINA_TMPDIR: /usr/local/tomcat/temp

Using JRE_HOME: /usr/java/jdk1.7.0_45/jre

Using CLASSPATH: /usr/local/tomcat/bin/bootstrap.jar

[root@2core local]# ps auxf|grep java

root 8220 0.0 0.0 103240 852 pts/0 S+ 10:19 0:00 \_ grep java

root 8201 179 6.7 1443396 68980 pts/0 Sl 10:19 0:05 /usr/java/jdk1.7.0_45/jre/bin/java -Djava.util.logging.config.file=/usr/local/tomcat/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLogManager -Djava.endorsed.dirs=/usr/local/tomcat/endorsed -classpath /usr/local/tomcat/bin/bootstrap.jar -Dcatalina.base=/usr/local/tomcat -Dcatalina.home=/usr/local/tomcat -Djava.io.tmpdir=/usr/local/tomcat/temp org.apache.catalina.startup.Bootstrap start

终于成功了！把iptables的TCP8080端口打开，便可以通过http://ip:8080访问了