That's probably possible, though hopefully they have installed system updates in the past year. We could just target 2022H2 and later if needed.
~ Ari Chivukula (Their/There/They're) On Thu, Jun 19, 2025 at 10:54 AM Jeremy Roman <jbro...@chromium.org> wrote: > > > On Thu, Jun 19, 2025 at 12:10 AM Domenic Denicola <dome...@chromium.org> > wrote: > >> I believe this should be completely unobservable to web authors, right? >> (Apart from maybe fewer or more network errors.) >> >> If so, I don't think this needs any LGTMs, as it fits well under the >> Web-developer-facing >> change to existing behavior >> <https://www.chromium.org/blink/launching-features/#behavior-changes> >> category. >> (Which is... confusingly named >> <https://github.com/GoogleChrome/chromium-dashboard/issues/5145>.) But, >> in case it helps, LGTM1. >> >> On Thursday, June 19, 2025 at 12:12:34 AM UTC+9 Ari Chivukula wrote: >> >>> Contact emails >>> >>> aric...@chromium.org, awil...@chromium.org, miketa...@chromium.org >>> Explainer >>> >>> None >>> Specification >>> >>> None >>> >>> Summary >>> >>> This launch enables TCP port randomization on versions of Windows (2020 >>> H1 or later) where we do not expect to see issues with re-use of prior >>> ports occurring too fast (causing rejection due to timeouts on port >>> re-use). The rapid port re-use issue arises from the Birthday problem >>> <https://en.wikipedia.org/wiki/Birthday_problem>, where the probability >>> of randomly re-picking a port already seen rapidly converges with 100% for >>> each new port chosen when compared to port re-use in a sequential model. >>> >>> >>> Blink component >>> >>> Blink>Network >>> <https://issues.chromium.org/issues?q=customfield1222907:%22Blink%3ENetwork%22> >>> >>> TAG review >>> >>> None >>> >>> TAG review status >>> >>> Not applicable >>> >>> >>> Motivation >>> >>> When port randomization is disabled (the default), sites are able to >>> count the amount of connections opened by other tabs if they check the TCP >>> port used for new connections before and after opening another window. This >>> knowledge can be used to glean information about other sites like whether >>> they are logged in or not. >>> >>> Risks >>> >>> Interoperability and Compatibility >>> >>> This launch only impacts Windows, and should not cause compatibility >>> issues as Microsoft backported their port randomization fix >>> <https://chromium-review.googlesource.com/c/chromium/src/+/5464674> to >>> Windows 10, 2020 H1 and tested it in Edge. >>> >> > Is it possible that we have users on versions >= 2020H1, < 2022H2 but who > have not received the backported fix (e.g., because they have not installed > the applicable update)? Would they encounter brokenness in Chrome? > > >>> Chrome previously attempted to roll this out in 2021 but ran into (since >>> resolved) issues where rapid port re-use caused network errors. >>> >>> Rollout on linux isn’t needed as port randomization is enabled by >>> default while on macOS an issue similar to the one on Windows with rapid >>> port re-use causing issues is still around. >>> >>> Gecko: Appears to inherit OS defaults >>> <https://github.com/search?q=repo%3Amozilla-firefox%2Ffirefox+setsockopt&type=code&p=1> >>> >>> WebKit: Appears to inherit OS defaults >>> <https://github.com/search?q=repo%3AWebKit%2FWebKit+setsockopt&type=code> >>> >>> Web developers: N/A >>> >>> Debuggability >>> >>> This will be gated behind the base::feature kTcpPortRandomizationWin, so >>> if breakage is suspected that flag could be turned off to detect impact. >>> For how to control feature flags, see this >>> <https://source.chromium.org/chromium/chromium/src/+/main:base/feature_list.h;drc=159a65729cf8fca4d9f453d12d97ab6515360491;l=259> >>> . >>> >>> Measurement >>> >>> The histogram Net.TCPSocket.PortReuseTimeWindows2.{IPType}.{Result} will >>> be used to gauge whether port re-use timings fall too low, while >>> Net.TcpConnectAttempt.Latency.{Result} will be used to detect increases in >>> overall connection failure rates. >>> >>> Will this feature be supported on all six Blink platforms (Windows, Mac, >>> Linux, ChromeOS, Android, and Android WebView)? >>> >>> No, just Windows >>> >>> Is this feature fully tested by web-platform-tests? >>> >>> No, as this is a blink networking focused change browser tests or unit >>> tests are more likely. >>> >>> Flag name on about://flags >>> >>> None >>> >>> Finch feature name >>> >>> kTcpPortRandomizationWin >>> >>> Rollout plan >>> >>> This will be rolled out slowly to detect issues early and either change >>> the version target or roll back. We don’t believe an experiment is needed >>> or desired as the issues we saw before were not very prevalent, we likely >>> need to go beyond 1% to get enough data on Windows to know if there’s still >>> a problem. >>> >>> Requires code in //chrome? >>> >>> No >>> >>> Tracking bug >>> >>> https://crbug.com/40744069 >>> >>> Estimated milestones >>> >>> 139 >>> >>> Link to entry on the Chrome Platform Status >>> >>> https://chromestatus.com/feature/5106900286570496 >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "blink-dev" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to blink-dev+unsubscr...@chromium.org. >> To view this discussion visit >> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/5ac125fa-3adf-4193-a1ff-1bf28f2f6020n%40chromium.org >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/5ac125fa-3adf-4193-a1ff-1bf28f2f6020n%40chromium.org?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "blink-dev" group. 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