Add iframe depth limit

[nt1m]

65071a6

Add iframe depth limit
https://bugs.webkit.org/show_bug.cgi?id=67940
rdar://101560112

Reviewed by Darin Adler and Alex Christensen.

* LayoutTests/fast/frames/frame-depth-limit-expected.txt: Added.
* LayoutTests/fast/frames/frame-depth-limit.html: Added.
* LayoutTests/fast/frames/resources/self-referential-iframe.html: Added.
* Source/WebCore/loader/SubframeLoader.cpp:
(WebCore::FrameLoader::SubframeLoader::loadSubframe):
* Source/WebCore/page/FrameTree.cpp:
(WebCore::FrameTree::depth const):
* Source/WebCore/page/FrameTree.h:
* Source/WebCore/page/Page.h:

Canonical link: https://commits.webkit.org/257550@main

bd2d9d3

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✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 gtk-wk2
	❌ 🧪 api-ios	✅ 🧪 mac-wk1	🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk2
	✅ 🛠 tv-sim	🧪 mac-AS-debug-wk2
✅ 🛠 🧪 merge	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 81fe57f)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 mac-wk1	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk2
	✅ 🛠 tv-sim	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[geoffreygaren]

Can you add a regression test?

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 158defa)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	🧪 ios-wk2	🧪 api-mac	✅ 🧪 gtk-wk2
	🧪 api-ios	🧪 mac-wk1	🧪 api-gtk
	✅ 🛠 tv	🧪 mac-wk2
	✅ 🛠 tv-sim	🧪 mac-AS-debug-wk2
	✅ 🛠 watch	🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[webkit-early-warning-system]

EWS run on current version of this PR (hash bd2d9d3)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 gtk-wk2
	❌ 🧪 api-ios	✅ 🧪 mac-wk1	🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk2
	✅ 🛠 tv-sim	🧪 mac-AS-debug-wk2
✅ 🛠 🧪 merge	✅ 🛠 watch	✅ 🧪 mac-wk2-stress
	✅ 🛠 watch-sim

[webkit-commit-queue]

Committed 257550@main (65071a6): https://commits.webkit.org/257550@main

Reviewed commits have been landed. Closing PR #7219 and removing active labels.

[csaavedra]

Why is the test not hitting the self-reference limit of 2 imposed by HTMLFrameOwnerElement::isProhibitedSelfReference(const URL& completeURL) ?

[nt1m]

Why is the test not hitting the self-reference limit of 2 imposed by HTMLFrameOwnerElement::isProhibitedSelfReference(const URL& completeURL) ?

That function seems to check for exact URL equality including query strings. The test changes the query string each time.

Either way, that protection is pretty weak, nothing prevents a website from generating identical self-referencing iframes server-side while changing the URL.