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https://issues.apache.org/jira/browse/WW-5677?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lukasz Lenart updated WW-5677:
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Fix Version/s: 7.4.0
> Remove the remaining redundant getPackage() lookups on the OGNL member-access
> path
> ----------------------------------------------------------------------------------
>
> Key: WW-5677
> URL: https://issues.apache.org/jira/browse/WW-5677
> Project: Struts 2
> Issue Type: Sub-task
> Reporter: Lukasz Lenart
> Priority: Major
> Fix For: 7.4.0
>
>
> Sub-task of WW-5667. Residual items found while reviewing WW-5674, which
> optimised {{isClassBelongsToPackages}} and {{toPackageName}} but deliberately
> left these two call sites alone as out of scope.
> Both sit on the same per-access hot path WW-5674 just optimised, within
> twenty lines of it, so leaving them is a visible inconsistency.
> h2. 1. {{checkDefaultPackageAccess}} makes four {{getPackage()}} calls
> {{SecurityMemberAccess.checkDefaultPackageAccess}} still calls
> {{clazz.getPackage()}} directly, twice per class and for up to two classes:
> {code:java}
> if (memberClass.getPackage() == null ||
> memberClass.getPackage().getName().isEmpty()) {
> {code}
> {{Class.getPackage()}} resolves through the defining classloader's package
> map on every call. WW-5674 removed exactly this lookup from {{toPackageName}}
> by switching to the cached {{Class.getPackageName()}}, so this method is now
> the only remaining user of the slow form.
> The condition is equivalent to {{toPackageName(memberClass).isEmpty()}} —
> including for arrays and primitives, where both forms treat the class as
> being in the default package and therefore block. Replacing it would also
> collapse the double {{getPackage()}} evaluation per class.
> Note that this method only runs when {{struts.disallowDefaultPackageAccess}}
> is enabled, so the impact is limited to deployments that turn it on.
> h2. 2. {{isExcludedPackageNamePatterns}} recomputes the package name per
> pattern
> {code:java}
> protected boolean isExcludedPackageNamePatterns(Class clazz) {
> return excludedPackageNamePatterns.stream().anyMatch(pattern ->
> pattern.matcher(toPackageName(clazz)).matches());
> }
> {code}
> {{toPackageName(clazz)}} is evaluated inside the lambda, so it runs once per
> pattern rather than once per call. Hoisting it out of the stream is a
> one-line change.
> The call is cheaper after WW-5674, but it is still N redundant calls.
> {{struts.excludedPackageNamePatterns}} is empty by default (both pattern
> constants are commented out in {{struts-excluded-classes.xml}}), so this only
> affects deployments that configure it.
> h2. Constraints
> This is the OGNL security gate. Both changes must be behaviour-preserving,
> and the equivalence of {{getPackage() == null ||
> getPackage().getName().isEmpty()}} with {{toPackageName(...).isEmpty()}} must
> be asserted by test rather than argued — in particular for arrays,
> primitives, {{void}} and default-package classes.
> {{SecurityMemberAccessPackageMatchingTest}} already provides the class-shape
> matrix and the frozen {{legacyToPackageName}} reference oracle to build on.
> h2. Related
> {{ConfigParseUtil.validatePackageNames}} evaluating
> {{Pattern.compile("\\s")}} once per package name rather than once overall is
> a per-instantiation cost, not a per-access one, and is tracked on WW-5675
> instead.
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