Bug 254732

Summary: Make SelectorQueryCache global
Product: WebKit Reporter: Antti Koivisto <koivisto>
Component: DOMAssignee: Antti Koivisto <koivisto>
Status: RESOLVED FIXED    
Severity: Normal CC: esprehn, webkit-bug-importer
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
See Also: https://bugs.webkit.org/show_bug.cgi?id=260556

Description Antti Koivisto 2023-03-30 04:31:30 PDT
It is currently per-Document.
Comment 1 Radar WebKit Bug Importer 2023-03-30 04:44:32 PDT
<rdar://problem/107414722>
Comment 2 Antti Koivisto 2023-03-30 04:58:36 PDT
Pull request: https://github.com/WebKit/WebKit/pull/12170
Comment 3 EWS 2023-03-30 13:25:58 PDT
Committed 262362@main (bc149c287545): <https://commits.webkit.org/262362@main>

Reviewed commits have been landed. Closing PR #12170 and removing active labels.
Comment 4 Elliott Sprehn 2024-01-09 13:08:42 PST
I think this introduces a performance cliff where documents with distinct selectors (ex with ids in them) fight over the cache. It also means there's a timing attack when process isolation is not enabled. You can call querySelector to see if a different origin has parsed a selector, which may also contain user identifiable information (ex. in attribute, id or class names)
Comment 5 Antti Koivisto 2024-01-10 08:10:44 PST
The cache key contains the security origin, I don't think there is attack like that.
Comment 6 Elliott Sprehn 2024-01-10 08:21:50 PST
Ah you're right, I missed that line:

Key { selectors, context, document.securityOrigin().data() };

that still means the cache is technically smaller in a process with many tabs or iframes, but I don't have data that shows that's an issue. Thanks for explaining!