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https://issues.apache.org/jira/browse/SLING-5946?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16988288#comment-16988288
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Ilguiz Latypov commented on SLING-5946:
---------------------------------------
Please reopen this due to an improper implementation risking exceptions in
strict javascript engines.
| return source == null ? null : Encode.forJavaScript(source).replace("\\-",
"\\u002D");|
Substitutes on top of the encoder's result with the intent to correct the
encoder are near-sighted (i.e. suffer from the context-free approach). If
{{source}} had a backslash followed by a dash {{raw \-}}, the {{forJavaScript}}
call would properly change the backslash into 2 backslashes {{raw \\-}} (this
would result in the javascript engine turning the string literal back to {{raw
\-}}). But the subsequent {{replace}} call will destroy the context of the
second backslash, turning the string into {{raw \\u002D}} which would turn to
{{raw \u002D}} in the javascript engine's variable.
I argue for dropping the {{.replace()}} call here and encoding the opening
angle bracket {{raw <}} as {{raw \u003C}} in the Encode.forJavaScript()
implementation. This will also protect against the closing script tags {{raw
</script>}} forcing the javascript interpreter to drop out of the string
literal context and drop out of the script context. The existing prefixing of
forward slashes with a backslash agrees with JSON but not with Javascript. It
should be removed in favour of replacing just the opening angle bracket.
> XSSAPI#encodeForJSString is not restrictive enough
> --------------------------------------------------
>
> Key: SLING-5946
> URL: https://issues.apache.org/jira/browse/SLING-5946
> Project: Sling
> Issue Type: Bug
> Components: Extensions
> Affects Versions: XSS Protection API 1.0.8
> Reporter: Vlad Bailescu
> Assignee: Robert Munteanu
> Priority: Major
> Fix For: XSS Protection API 1.0.12
>
> Attachments: SLING_5946.patch
>
>
> Since SLING-5445, {{XSSAPI#encodeForJSString}} is no longer properly encoding
> {{</script>}} and {{<!--}}. We should revert to using OWASP
> {{Encode#forJavaScript}} and handle - characters correctly for JSON too, by
> replacing them with {{\u002D}}
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