Links User Guide Reference Apache Tomcat Development | Background |
The Java SecurityManager is what allows a web browser
to run an applet in its own sandbox to prevent untrusted code from
accessing files on the local file system, connecting to a host other
than the one the applet was loaded from, and so on. In the same way
the SecurityManager protects you from an untrusted applet running in
your browser, use of a SecurityManager while running Tomcat can protect
your server from trojan servlets, JSPs, JSP beans, and tag libraries.
Or even inadvertent mistakes.
Imagine if someone who is authorized to publish JSPs on your site
inadvertently included the following in their JSP:
Every time this JSP was executed by Tomcat, Tomcat would exit.
Using the Java SecurityManager is just one more line of defense a
system administrator can use to keep the server secure and reliable.
WARNING - A security audit
have been conducted using the Tomcat 5 codebase. Most of the critical
package have been protected and a new security package protection mechanism
has been implemented. Still, make sure that you are satisfied with your SecurityManager
configuration before allowing untrusted users to publish web applications,
JSPs, servlets, beans, or tag libraries. However, running with a
SecurityManager is definitely better than running without one.
|
Permissions |
Permission classes are used to define what Permissions a class loaded
by Tomcat will have. There are a number of Permission classes that are
a standard part of the JDK, and you can create your own Permission class
for use in your own web applications. Both techniques are used in
Tomcat 5.
Standard Permissions |
This is just a short summary of the standard system SecurityManager
Permission classes applicable to Tomcat. See
http://java.sun.com/security/
for more information.
- java.util.PropertyPermission - Controls read/write
access to JVM properties such as
java.home .
- java.lang.RuntimePermission - Controls use of
some System/Runtime functions like
exit() and
exec() . Also control the package access/definition.
- java.io.FilePermission - Controls read/write/execute
access to files and directories.
- java.net.SocketPermission - Controls use of
network sockets.
- java.net.NetPermission - Controls use of
multicast network connections.
- java.lang.reflect.ReflectPermission - Controls
use of reflection to do class introspection.
- java.security.SecurityPermission - Controls access
to Security methods.
- java.security.AllPermission - Allows access to all
permissions, just as if you were running Tomcat without a
SecurityManager.
|
|
Configuring Tomcat With A SecurityManager |
Policy File Format
The security policies implemented by the Java SecurityManager are
configured in the $CATALINA_HOME/conf/catalina.policy file.
This file completely replaces the java.policy file present
in your JDK system directories. The catalina.policy file
can be edited by hand, or you can use the
policytool
application that comes with Java 1.2 or later.
Entries in the catalina.policy file use the standard
java.policy file format, as follows:
![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
// Example policy file entry
grant [signedBy <signer>,] [codeBase <code source>] {
permission <class> [<name> [, <action list>]];
};
| ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
The signedBy and codeBase entries are
optional when granting permissions. Comment lines begin with "//" and
end at the end of the current line. The codeBase is in the
form of a URL, and for a file URL can use the ${java.home}
and ${catalina.home} properties (which are expanded out to
the directory paths defined for them by the JAVA_HOME and
CATALINA_HOME environment variables).
The Default Policy File
The default $CATALINA_HOME/conf/catalina.policy file
looks like this:
![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
// ============================================================================
// catalina.corepolicy - Security Policy Permissions for Tomcat 5
//
// This file contains a default set of security policies to be enforced (by the
// JVM) when Catalina is executed with the "-security" option. In addition
// to the permissions granted here, the following additional permissions are
// granted to the codebase specific to each web application:
//
// * Read access to the document root directory
//
// $Id: security-manager-howto.xml 565211 2007-08-13 00:09:38Z markt $
// ============================================================================
// ========== SYSTEM CODE PERMISSIONS =========================================
// These permissions apply to javac
grant codeBase "file:${java.home}/lib/-" {
permission java.security.AllPermission;
};
// These permissions apply to all shared system extensions
grant codeBase "file:${java.home}/jre/lib/ext/-" {
permission java.security.AllPermission;
};
// These permissions apply to javac when ${java.home] points at $JAVA_HOME/jre
grant codeBase "file:${java.home}/../lib/-" {
permission java.security.AllPermission;
};
// These permissions apply to all shared system extensions when
// ${java.home} points at $JAVA_HOME/jre
grant codeBase "file:${java.home}/lib/ext/-" {
permission java.security.AllPermission;
};
// ========== CATALINA CODE PERMISSIONS =======================================
// These permissions apply to the launcher code
grant codeBase "file:${catalina.home}/bin/commons-launcher.jar" {
permission java.security.AllPermission;
};
// These permissions apply to the server startup code
grant codeBase "file:${catalina.home}/bin/bootstrap.jar" {
permission java.security.AllPermission;
};
// These permissions apply to the servlet API classes
// and those that are shared across all class loaders
// located in the "common" directory
grant codeBase "file:${catalina.home}/common/-" {
permission java.security.AllPermission;
};
// These permissions apply to the container's core code, plus any additional
// libraries installed in the "server" directory
grant codeBase "file:${catalina.home}/server/-" {
permission java.security.AllPermission;
};
// ========== WEB APPLICATION PERMISSIONS =====================================
// These permissions are granted by default to all web applications
// In addition, a web application will be given a read FilePermission
// and JndiPermission for all files and directories in its document root.
grant {
// Required for JNDI lookup of named JDBC DataSource's and
// javamail named MimePart DataSource used to send mail
permission java.util.PropertyPermission "java.home", "read";
permission java.util.PropertyPermission "java.naming.*", "read";
permission java.util.PropertyPermission "javax.sql.*", "read";
// OS Specific properties to allow read access
permission java.util.PropertyPermission "os.name", "read";
permission java.util.PropertyPermission "os.version", "read";
permission java.util.PropertyPermission "os.arch", "read";
permission java.util.PropertyPermission "file.separator", "read";
permission java.util.PropertyPermission "path.separator", "read";
permission java.util.PropertyPermission "line.separator", "read";
// JVM properties to allow read access
permission java.util.PropertyPermission "java.version", "read";
permission java.util.PropertyPermission "java.vendor", "read";
permission java.util.PropertyPermission "java.vendor.url", "read";
permission java.util.PropertyPermission "java.class.version", "read";
permission java.util.PropertyPermission "java.specification.version", "read";
permission java.util.PropertyPermission "java.specification.vendor", "read";
permission java.util.PropertyPermission "java.specification.name", "read";
permission java.util.PropertyPermission "java.vm.specification.version", "read";
permission java.util.PropertyPermission "java.vm.specification.vendor", "read";
permission java.util.PropertyPermission "java.vm.specification.name", "read";
permission java.util.PropertyPermission "java.vm.version", "read";
permission java.util.PropertyPermission "java.vm.vendor", "read";
permission java.util.PropertyPermission "java.vm.name", "read";
// Required for getting BeanInfo
permission java.lang.RuntimePermission "accessClassInPackage.sun.beans.*";
// Required for OpenJMX
permission java.lang.RuntimePermission "getAttribute";
// Allow read of JAXP compliant XML parser debug
permission java.util.PropertyPermission "jaxp.debug", "read";
};
// You can assign additional permissions to particular web applications by
// adding additional "grant" entries here, based on the code base for that
// application, /WEB-INF/classes/, or /WEB-INF/lib/ jar files.
//
// Different permissions can be granted to JSP pages, classes loaded from
// the /WEB-INF/classes/ directory, all jar files in the /WEB-INF/lib/
// directory, or even to individual jar files in the /WEB-INF/lib/ directory.
//
// For instance, assume that the standard "examples" application
// included a JDBC driver that needed to establish a network connection to the
// corresponding database and used the scrape taglib to get the weather from
// the NOAA web server. You might create a "grant" entries like this:
//
// The permissions granted to the context root directory apply to JSP pages.
// grant codeBase "file:${catalina.home}/webapps/examples/-" {
// permission java.net.SocketPermission "dbhost.mycompany.com:5432", "connect";
// permission java.net.SocketPermission "*.noaa.gov:80", "connect";
// };
//
// The permissions granted to the context WEB-INF/classes directory
// grant codeBase "file:${catalina.home}/webapps/examples/WEB-INF/classes/-" {
// };
//
// The permission granted to your JDBC driver
// grant codeBase "jar:file:${catalina.home}/webapps/examples/WEB-INF/lib/driver.jar!/-" {
// permission java.net.SocketPermission "dbhost.mycompany.com:5432", "connect";
// };
// The permission granted to the scrape taglib
// grant codeBase "jar:file:${catalina.home}/webapps/examples/WEB-INF/lib/scrape.jar!/-" {
// permission java.net.SocketPermission "*.noaa.gov:80", "connect";
// };
| ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
Starting Tomcat With A SecurityManager
Once you have configured the catalina.policy file for use
with a SecurityManager, Tomcat can be started with a SecurityManager in
place by using the "-security" option:
![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
$CATALINA_HOME/bin/catalina.sh start -security (Unix)
%CATALINA_HOME%\bin\catalina start -security (Windows)
| ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
|
Configuring Package Protection in Tomcat |
Starting with Tomcat 5, it is now possible to configure which Tomcat
internal package are protected againts package definition and access. See
http://java.sun.com/security/seccodeguide.html
for more information.
WARNING: Be aware that removing the default package protection
could possibly open a security hole
The Default Properties File
The default $CATALINA_HOME/conf/catalina.properties file
looks like this:
![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
#
# List of comma-separated packages that start with or equal this string
# will cause a security exception to be thrown when
# passed to checkPackageAccess unless the
# corresponding RuntimePermission ("accessClassInPackage."+package) has
# been granted.
package.access=sun.,org.apache.catalina.,org.apache.coyote.,org.apache.tomcat.,
org.apache.jasper.
#
# List of comma-separated packages that start with or equal this string
# will cause a security exception to be thrown when
# passed to checkPackageDefinition unless the
# corresponding RuntimePermission ("defineClassInPackage."+package) has
# been granted.
#
# by default, no packages are restricted for definition, and none of
# the class loaders supplied with the JDK call checkPackageDefinition.
#
package.definition=sun.,java.,org.apache.catalina.,org.apache.coyote.,
org.apache.tomcat.,org.apache.jasper.
| ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) | ![](./images/void.gif) |
Once you have configured the catalina.properties file for use
with a SecurityManager, remember to re-start Tomcat.
|
|