Repository: struts-site Updated Branches: refs/heads/master f2d8b61c3 -> 680619b02
update security page Project: http://git-wip-us.apache.org/repos/asf/struts-site/repo Commit: http://git-wip-us.apache.org/repos/asf/struts-site/commit/680619b0 Tree: http://git-wip-us.apache.org/repos/asf/struts-site/tree/680619b0 Diff: http://git-wip-us.apache.org/repos/asf/struts-site/diff/680619b0 Branch: refs/heads/master Commit: 680619b02e33462732b1733d9ab1ab9b09d91027 Parents: f2d8b61 Author: Aleksandr Mashchenko <[email protected]> Authored: Thu Jun 15 23:58:36 2017 +0300 Committer: Aleksandr Mashchenko <[email protected]> Committed: Thu Jun 15 23:58:36 2017 +0300 ---------------------------------------------------------------------- source/security/index.md | 276 +++++++++++------------------------------- 1 file changed, 68 insertions(+), 208 deletions(-) ---------------------------------------------------------------------- http://git-wip-us.apache.org/repos/asf/struts-site/blob/680619b0/source/security/index.md ---------------------------------------------------------------------- diff --git a/source/security/index.md b/source/security/index.md index 3d52c6c..fcd6e2c 100644 --- a/source/security/index.md +++ b/source/security/index.md @@ -6,53 +6,37 @@ title: Security (WIP) # Security -#####Security tips##### +### Security tips -The Apache Struts 2 doesn't provide any security mechanism \- it is just a pure web framework\. Below are few tips you should consider during application development with the Apache Struts 2\. +The Apache Struts 2 doesn't provide any security mechanism - it is just a pure web framework. Below are few tips you should consider during application development with the Apache Struts 2. -__Restrict access to the Config Browser__ +#### Restrict access to the Config Browser Plugin -_Config Browser Plugin_  exposes internal configuration and should be used only during development phase\. If you must use it on production site, we strictly recommend restricting access to it \- you can use  Basic Authentication or any other security mechanism (e\.g\. [Apache Shiro](http://shiro\.apache\.org/)^[http://shiro\.apache\.org/]) +[Config Browser Plugin](https://struts.apache.org/docs/config-browser-plugin.html) exposes internal configuration and should be used only during development phase. If you must use it on production site, we strictly recommend restricting access to it - you can use  Basic Authentication or any other security mechanism (e.g. [Apache Shiro](https://shiro.apache.org/)) -__Don't mix different access levels in the same namespace__ +#### Don't mix different access levels in the same namespace -Very often access to different resources is controlled based on URL patterns, see snippet below\. Because of that you cannot mix actions with different security levels in the same namespace\. Always group actions in one namespace by security level\. +Very often access to different resources is controlled based on URL patterns, see snippet below. Because of that you cannot mix actions with different security levels in the same namespace. Always group actions in one namespace by security level. -~~~~~~~ - <security-constraint> - <web-resource-collection> - <web-resource-name>admin</web-resource-name> - <url-pattern>/secure/*</url-pattern> - </web-resource-collection> - <auth-constraint> - <role-name>admin</role-name> - </auth-constraint> - </security-constraint> - -~~~~~~~ - -__Never expose JSP files directly__ - -You must always hide JSP file behind an action, you cannot allow for direct access to the JSP files as this can leads to unpredictable security vulnerabilities\. You can achieve this by putting all your JSP files under the - -~~~~~~~ -WEB-INF -~~~~~~~ - folder \- most of the JEE containers restrict access to files placed under the +```xml +<security-constraint> + <web-resource-collection> + <web-resource-name>admin</web-resource-name> + <url-pattern>/secure/*</url-pattern> + </web-resource-collection> + <auth-constraint> + <role-name>admin</role-name> + </auth-constraint> +</security-constraint> +``` -~~~~~~~ -WEB-INF -~~~~~~~ - folder\. Second option is to add security constraint to the +#### Never expose JSP files directly -~~~~~~~ -web.xml -~~~~~~~ - file: +You must always hide JSP file behind an action, you cannot allow for direct access to the JSP files as this can leads to unpredictable security vulnerabilities. You can achieve this by putting all your JSP files under the `WEB-INF` folder - most of the JEE containers restrict access to files placed under the `WEB-INF` folder. Second option is to add security constraint to the `web.xml` file: -~~~~~~~ +```xml <!-- Restricts access to pure JSP files - access available only via Struts action --> <security-constraint> <display-name>No direct JSP access</display-name> @@ -69,53 +53,29 @@ web.xml <description>Don't assign users to this role</description> <role-name>no-users</role-name> </security-role> -~~~~~~~ +``` -The best approach is to used the both solutions\. +The best approach is to used the both solutions. -__Disable devMode__ +#### Disable devMode -The +The `devMode` is a very useful option during development time, allowing for deep introspection and debugging into you app. -~~~~~~~ -devMode -~~~~~~~ - is a very useful option during development time, allowing for deep introspection and debugging into you app\. +However, in production it exposes your application to be presenting too many informations on application's internals or to evaluating risky parameter expressions. Please **always disable** `devMode` before deploying your application to a production environment. While it is disabled by default, your +`struts.xml` might include a line setting it to `true`. The best way is to ensure the following setting is applied to our `struts.xml` for production deployment: -However, in production it exposes your application to be presenting too many informations on application's internals or to evaluating risky parameter expressions\. Please **always disable -~~~~~~~ -devMode -~~~~~~~ -** before deploying your application to a production environment\. While it is disabled by default, your +```xml +<constant name ="struts.devMode" value="false" /> +``` + -~~~~~~~ -struts.xml -~~~~~~~ - might include a line setting it to +#### Reduce logging level -~~~~~~~ -true -~~~~~~~ -\. The best way is to ensure the following setting is applied to our + It's a good practice to reduce logging level from **DEBUG** to **INFO** or less. Framework's classes can produce a lot of logging entries which will pollute the log file. You can even set logging level to **WARN** for classes that belongs to the framework, see example Log4j2 configuration: -~~~~~~~ -struts.xml -~~~~~~~ - for production deployment: - - -| \< constant name ="struts\.devMode" value="false" /\> - -| - -__Reduce logging level__ - - It's a good practice to reduce logging level from **DEBUG** to **INFO** or less\. Framework's classes can produce a lot of logging entries which will pollute the log file\. You can even set logging level to **WARN** for classes that belongs to the framework, see example Log4j2 configuration: - - -~~~~~~~ +```xml <?xml version="1.0" encoding="UTF-8"?> <Configuration> <Appenders> @@ -131,115 +91,52 @@ __Reduce logging level__ </Root> </Loggers> </Configuration> -~~~~~~~ +``` -__Use UTF\-8 encoding__ +#### Use UTF-8 encoding -Always use +Always use `UTF-8` encoding when building an application with the Apache Struts 2, when using JSPs please add the following header to each JSP file -~~~~~~~ -UTF-8 -~~~~~~~ - encoding when building an application with the Apache Struts 2, when using JSPs please add the following header to each JSP file - -~~~~~~~ +```jsp <%@ page contentType="text/html; charset=UTF-8" %> -~~~~~~~ - -__Do not define setters when not needed__ +``` -You should carefully design your actions without exposing anything via setters and getters, thus can leads to potential security vulnerabilities\. Any action's setter can be used to set incoming untrusted user's value which can contain suspicious expression\. Some Struts +#### Do not define setters when not needed -~~~~~~~ -Result -~~~~~~~ -s automatically populate params based on values in +You should carefully design your actions without exposing anything via setters and getters, thus can leads to potential security vulnerabilities. Any action's setter can be used to set incoming untrusted user's value which can contain suspicious expression. Some Struts `Result`s automatically populate params based on values in +`ValueStack` (action in most cases is the root) which means incoming value will be evaluated as an expression during this process. -~~~~~~~ -ValueStack -~~~~~~~ - (action in most cases is the root) which means incoming value will be evaluated as an expression during this process\. +#### Do not use incoming values as an input for localisation logic -__Do not use incoming values as an input for localisation logic__ +All `TextProvider`'s `getText(...)` methods (e.g. in`ActionSupport`) perform evaluation of parameters included in a message to properly localize the text. This means using incoming request parameters with `getText(...)` methods is potentially dangerous and should be avoided. See example below, assuming that an action implements getter and setter for property `message`, the below code allows inject an OGNL expression: -All -~~~~~~~ -TextProvider -~~~~~~~ -'s - -~~~~~~~ -getText(...) -~~~~~~~ -methods (e\.g in - -~~~~~~~ -ActionSupport -~~~~~~~ -) perform evaluation of parameters included in a message to properly localize the text\. This means using incoming request parameters with - -~~~~~~~ -getText(...) -~~~~~~~ - methods is potentially dangerous and should be avoided\. See example below, assuming that an action implements getter and setter for property - -~~~~~~~ -message -~~~~~~~ -, the below code allows inject an OGNL expression: - - -~~~~~~~ +```java public String execute() throws Exception { setMessage(getText(getMessage())); return SUCCESS; } -~~~~~~~ +``` -Never use value of incoming request parameter as part of your localisation logic\. +Never use value of incoming request parameter as part of your localization logic. -#####Internal security mechanism##### +### Internal security mechanism -The Apache Struts 2 contains internal security manager which blocks access to particular classes and Java packages \- it's a OGNL\-wide mechanism which means it affects any aspect of the framework ie\. incoming parameters, expressions used in JSPs, etc\. +The Apache Struts 2 contains internal security manager which blocks access to particular classes and Java packages - it's a OGNL-wide mechanism which means it affects any aspect of the framework ie. incoming parameters, expressions used in JSPs, etc. There are three options that can be used to configure excluded packages and classes: -+ - -~~~~~~~ -struts.excludedClasses -~~~~~~~ - \- comma\-separated list of excluded classes - -+ - -~~~~~~~ -struts.excludedPackageNamePatterns -~~~~~~~ - \- patterns used to exclude packages based on RegEx \- this option is slower than simple string comparison but it's more flexible - -+ +- `struts.excludedClasses` - comma-separated list of excluded classes -~~~~~~~ -struts.excludedPackageNames -~~~~~~~ - \- comma\-separated list of excluded packages, it is used with simple string comparison via +- `struts.excludedPackageNamePatterns` - patterns used to exclude packages based on RegEx - this option is slower than simple string comparison but it's more flexible -~~~~~~~ -startWith -~~~~~~~ - and - -~~~~~~~ -equals -~~~~~~~ +- `struts.excludedPackageNames` - comma-separated list of excluded packages, it is used with simple string comparison via `startWith` and `equals` The defaults are as follow: -~~~~~~~ +```xml <constant name="struts.excludedClasses" value="com.opensymphony.xwork2.ActionContext" /> @@ -249,48 +146,31 @@ The defaults are as follow: <!-- this is simpler version of the above used with string comparison --> <constant name="struts.excludedPackageNames" value="java.lang,ognl,javax" /> -~~~~~~~ +``` Any expression or target which evaluates to one of these will be blocked and you see a WARN in logs: -~~~~~~~ +``` [WARNING] Target class [class example.MyBean] or declaring class of member type [public example.MyBean()] are excluded! -~~~~~~~ - -In that case - -~~~~~~~ -new MyBean() -~~~~~~~ - was used to create a new instance of class (inside JSP) \- it's blocked because - -~~~~~~~ -target -~~~~~~~ - of such expression is evaluated to - -~~~~~~~ -java.lang.Class -~~~~~~~ +``` +In that case `new MyBean()` was used to create a new instance of class (inside JSP) - it's blocked because `target` of such expression is evaluated to `java.lang.Class` -It is possible to redefine the above constants in struts\.xml but try to avoid this and rather change design of your application\! +It is possible to redefine the above constants in struts.xml but try to avoid this and rather change design of your application! -| -__Accessing static methods__ +#### Accessing static methods -Support for accessing static methods from expression will be disabled soon, please consider re\-factoring your application to avoid further problems\! Please check [WW\-4348](https://issues\.apache\.org/jira/browse/WW\-4348)^[https://issues\.apache\.org/jira/browse/WW\-4348]\. +Support for accessing static methods from expression will be disabled soon, please consider re-factoring your application to avoid further problems! Please check [WW-4348](https://issues.apache.org/jira/browse/WW-4348). -> -__OGNL is used to call action's methods__ +#### OGNL is used to call action's methods -This can impact actions which have large inheritance hierarchy and use the same method's name throughout the hierarchy, this was reported as an issue [WW\-4405](https://issues\.apache\.org/jira/browse/WW\-4405)^[https://issues\.apache\.org/jira/browse/WW\-4405]\. See the example below: +This can impact actions which have large inheritance hierarchy and use the same method's name throughout the hierarchy, this was reported as an issue [WW-4405](https://issues.apache.org/jira/browse/WW-4405). See the example below: -~~~~~~~ +```java public class RealAction extends BaseAction { @Action("save") public String save() throws Exception { @@ -311,34 +191,14 @@ public abstract class AbstractAction extends ActionSupport { // some logic } } -~~~~~~~ - -In such case OGNL cannot properly map which method to call when request is coming\. This is do the OGNL limitation\. To solve the problem don't use the same method's names through the hierarchy, you can simply change the action's method from - -~~~~~~~ -save() -~~~~~~~ - to - -~~~~~~~ -saveAction() -~~~~~~~ - and leaving annotation as is to allow call this action via - -~~~~~~~ -/save.action -~~~~~~~ - request\. +``` -__Accepted / Excluded patterns__ +In such case OGNL cannot properly map which method to call when request is coming. This is do the OGNL limitation. To solve the problem don't use the same method's names through the hierarchy, you can simply change the action's method from `save()` to `saveAction()` and leaving annotation as is to allow call this action via `/save.action` request. - As from version 2\.3\.20 the framework provides two new interfaces which are used to accept / exclude param names and values \- [AcceptedPatternsChecker](http://struts\.apache\.org/maven/struts2\-core/apidocs/com/opensymphony/xwork2/security/AcceptedPatternsChecker\.html)^[http://struts\.apache\.org/maven/struts2\-core/apidocs/com/opensymphony/xwork2/security/AcceptedPatternsChecker\.html] and [ExcludedPatternsChecker](http://struts\.apache\.org/maven/struts2\-core/apidocs/com/opensymphony/xwork2/security/ExcludedPatternsChecker\.html)^[http://struts\.apache\.org/maven/struts2\-core/apidocs/com/opensymphony/xwork2/security/ExcludedPatternsChecker\.html] with default implementations\. These two interfaces are used by [Parameters Interceptor](../core-developers/parameters-interceptor.html) and [Cookie Interceptor](../core-developers/cookie-interceptor.html) to check if param can be accepted or must be excluded\. If you were using +#### Accepted / Excluded patterns -~~~~~~~ -excludeParams -~~~~~~~ - previously please compare patterns used by you with these provided by the framework in default implementation\. + As from version 2.3.20 the framework provides two new interfaces which are used to accept / exclude param names and values - [AcceptedPatternsChecker](https://struts.apache.org/maven/struts2-core/apidocs/com/opensymphony/xwork2/security/AcceptedPatternsChecker.html) and [ExcludedPatternsChecker](https://struts.apache.org/maven/struts2-core/apidocs/com/opensymphony/xwork2/security/ExcludedPatternsChecker.html) with default implementations. These two interfaces are used by [Parameters Interceptor](../core-developers/parameters-interceptor.html) and [Cookie Interceptor](../core-developers/cookie-interceptor.html) to check if param can be accepted or must be excluded. If you were using `excludeParams` previously please compare patterns used by you with these provided by the framework in default implementation. -__Strict Method Invocation__ +#### Strict Method Invocation - This mechanism was introduced in version 2\.5\. It allows control what methods can be accessed with the bang "\!" operator via [Dynamic Method Invocation](../core-developers/action-configuration.html#dynamic-method-invocation)\. Please read more in Strict Method Invocation section of [Action Configuration](../core-developers/action-configuration.html). \ No newline at end of file + This mechanism was introduced in version 2.5. It allows control what methods can be accessed with the bang "!" operator via [Dynamic Method Invocation](../core-developers/action-configuration.html#dynamic-method-invocation). Please read more in Strict Method Invocation section of [Action Configuration](../core-developers/action-configuration.html).
