Tighten AdvWebView WebView posture#150
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AdvWebView.init() turned on three settings that loosen the WebView sandbox more than the forum-client code actually needs: - setMixedContentMode(MIXED_CONTENT_ALWAYS_ALLOW) - setAllowFileAccessFromFileURLs(true) - setAllowUniversalAccessFromFileURLs(true) The HTML rendered into AdvWebView is always built locally by HtmlBuilder / TopicBodyBuilder / QmsHtmlBuilder and either points the WebView at an https://forum-host/forum/ base URL or references bundled resources via file:///android_asset/. The android_asset scheme is permitted regardless of the file flags, so neither FromFileURLs flag is load-bearing for any of the existing call sites. Replace MIXED_CONTENT_ALWAYS_ALLOW with MIXED_CONTENT_COMPATIBILITY_MODE, which keeps passive sub-resources (images, fonts) loading on https forum pages while blocking active mixed content like remote scripts. Remove the two setAllow*FromFileURLs(true) calls. The dev comment on the first one already said 'Maybe you don't need this rule' -- confirmed, neither is needed. setAllowFileAccess(true) is left in place because removing it would require a wider audit of every fragment that constructs an AdvWebView.
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Closes #149.
AdvWebView.init()turns on three settings that loosen the WebView sandbox more than the forum-client actually needs:The HTML rendered into
AdvWebViewis always built locally byHtmlBuilder,TopicBodyBuilderorQmsHtmlBuilder. The page is either pointed at anhttps://forum-host/forum/base URL (BbCodesQuickView.loadDataWithBaseURL) or references bundled resources viafile:///android_asset/. Theandroid_assetscheme is permitted regardless of the file flags, so neitherFromFileURLsflag is load-bearing for any of the existing WebView paths. The dev comment on the first call (Maybe you don't need this rule) already flags the uncertainty.Change
setMixedContentMode(MIXED_CONTENT_ALWAYS_ALLOW)->setMixedContentMode(MIXED_CONTENT_COMPATIBILITY_MODE).COMPATIBILITY_MODEkeeps passive sub-resources (images, fonts) loading on an https forum page while blocking active mixed content like remote scripts. This is the right default for user-generated forum content.Drop
setAllowFileAccessFromFileURLs(true)andsetAllowUniversalAccessFromFileURLs(true). Neither one takes effect when the main frame is an https URL, and they are CWE-200 sandbox-escape vectors when left on.Out of scope
setAllowFileAccess(true)is left in place. Removing it would need a wider audit of every fragment that builds its ownAdvWebView(ForumRulesFragment,SpecialView,ProfileEditFragment,QmsChatFragment,SearchPostFragment,PostPreviewFragment,ThemeFragment,MentionsListFragment), so I have kept this PR to the centralAdvWebViewonly.