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https://issues.apache.org/jira/browse/CLOWNFISH-62?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Nick Wellnhofer resolved CLOWNFISH-62.
--------------------------------------
Resolution: Fixed
Fix Version/s: 0.5.0
It turns out that my analysis was wrong. Decremented arguments were incref'd
but the return value was discarded, breaking the copy-on-incref mechanism.
> Crash when passing Perl variable as decremented arg
> ---------------------------------------------------
>
> Key: CLOWNFISH-62
> URL: https://issues.apache.org/jira/browse/CLOWNFISH-62
> Project: Apache Lucy-Clownfish
> Issue Type: Bug
> Components: Perl
> Affects Versions: 0.4.0, 0.5.0
> Reporter: Nick Wellnhofer
> Fix For: 0.5.0
>
>
> Passing a Perl variable to a method that takes a "decremented" argument
> results in a use-after-free. Example
> {noformat}
> perl -MClownfish -e 'Clownfish::Vector->new->push("abc")'
> {noformat}
> Analysis:
> - A Clownfish "stack" string is created from the string value of the Perl
> variable.
> - The stack string is passed to Vec_Push.
> - The stack string is never incref'd.
> - The copy-on-incref mechanism isn't invoked.
> - When the Vector is destroyed, the stack string is decref'd, accessing
> random stack memory.
> A possible solution is to forgo the stack string optimization for decremented
> arguments.
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