On Wed, Aug 18, 2021 at 5:23 PM Yoav Weiss <[email protected]> wrote:
> > > On Wed, Aug 18, 2021 at 11:18 PM Matt Menke <[email protected]> wrote: > >> On Wed, Aug 18, 2021 at 4:53 PM Yoav Weiss <[email protected]> >> wrote: >> >>> >>> >>> On Wed, Aug 18, 2021 at 8:47 PM 'Matt Menke' via blink-dev < >>> [email protected]> wrote: >>> >>>> Contact [email protected] >>>> >>>> ExplainerNone >>>> >>>> Specificationhttps://url.spec.whatwg.org/ >>>> >>>> Summary >>>> >>>> Most hostnames that aren't valid IPv4 addresses, but end in numbers are >>>> treated as valid, and looked up via DNS (e.g., http://foo.127.1/). Per >>>> the Public Suffix List spec, the eTLD+1 of the hostname in that URL should >>>> be "127.1". If that is ever fed back into a URLs, "http://127.1/ >>>> <http://127.0.0.1/>" is mapped to "http://127.0.0.1/"; by the URL spec, >>>> which seems potentially dangerous. "127.0.0.0.1" could also potentially be >>>> used to confuse users. We want to reject URLs with these hostnames. >>>> >>>> >>>> Blink componentInternals>Network>DNS >>>> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Internals%3ENetwork%3EDNS> >>>> >>>> Motivation >>>> >>>> Most hostnames that aren't valid IPv4 addresses, but end in numbers are >>>> treated as valid hostnames, and looked up via DNS. Example hostnames: >>>> 127.0.0.0.1, foo.0.1, 10.0.0.09, 08.1.2.3. These can be problematic for the >>>> following reason: * "http://foo.127.1/"; has an eTLD+1 of "127.1", per >>>> the public suffix list spec. If that's ever used as the hostname in a new >>>> URL, however, as in "http://127.1 <http://127.0.0.1/>", it will then >>>> get mapped to "http://127.0.0.1/";, per the URL spec, which is a >>>> different host, which is not safe. * "http://127.0.0.0.1"; and " >>>> http://1.2.3.09";, both of which are looked up via DNS rather than >>>> failing or being treated as IPv4 hostnames, also seem potentially >>>> confusing. While no exploit is currently known here, we want to remove >>>> support for these as a preventative security measure. The URL spec has been >>>> updated so that any URL with a hostname ending in a number that's not an >>>> IPv4 address (including, e.g., http://foo.1./, but not http://foo.1../) >>>> is considered invalid. Since this is part of the URL spec, not the DNS >>>> spec, we want to reject these URLs are the GURL layer, for URLs with >>>> appropriate protocols (http, https, ws, wss, file). For consistency, we >>>> should also fail DNS lookup attempts of these sorts of hostnames. >>>> >>>> >>>> Initial public proposalhttps://github.com/whatwg/url/pull/619 >>>> >>>> TAG reviewNot required for an Intent to Deprecate, I believe. >>>> >>>> TAG review statusNot applicable >>>> >>>> Risks >>>> >>>> >>>> Interoperability and Compatibility >>>> >>>> Any URL with an affected hostname will fail to load, and will need to >>>> be migrated to another hostname. URLs of this form do appear to be in use, >>>> though it's not clear under what circumstances. No entry in the public >>>> suffix list is affected. Affected URLs make up no more than 0.0003% of >>>> hostnames looked up via the host resolver on any platform, and are >>>> basically not used in any file URLs, according to our metrics. >>>> >>> >>> Do we have reason to believe these hostnames are not legitimate ones? >>> >> >> Unfortunately, we have no insight into them - they could be mistyped URLs >> sent to typo squatting ISPs that OSX lets through but the Windows host >> resolver blocks, and various flavors of Linux treat differently. Or they >> could be mapped via a hosts file, or they could be hostnames that only >> resolve on public networks. Could be some network tool that uses them when >> installed locally, but is only available on certain platforms. No reason >> to think one possibility is more likely than the others. >> > > Do we have UKM for them that would enable us to test a random sample? > I'm concerned about blocking those hostnames if they are legitimate, as > that's something that a web developer can't do anything about. > So even if the number of hosts is small, I'd like to get more certainty > that they are *not* legitimate hosts before blocking them. > We have UKM on their number (0.0003% of DNS lookups on OSX, less elsewhere - we can't meaningfully instrument percent of created GURLs), but we don't have their hostnames, what they resolve to, or know anything else about them, unfortunately. Navigation to a subset of these as frame URLs were broken at one point - I'm pretty sure the breakage even made it to stable: https://crbug.com/1173238. There were no reports of problems. Only non-IPv4 URLs where the last two components were broken, though, and it didn't affect subresources. On OSX and Android, over 99% of successfully resolved problematic hostnames fit into that bucket, though on Linux, only about 2% do. That doesn't give us any hard conclusions, except they're either not deliberate navigations on OSX/Android, or they're not navigations. > >> >> >>> >>>> On OSX and Android, about 90% of host resolver lookups for these >>>> hostnames succeed, 60% do on Linux, and 2% on Windows and ChromeOS. >>>> >>> >>> Do you know where those failures are coming from? >>> >> >> Could be typos, could be the Windows and ChromeOS host resolvers don't >> let them through. Since we've had no filed bugs about them, I suspect the >> failures are not deliberate navigations or intended network requests. I'm >> much more interested in where the successes are coming from, myself. >> >> >>> >>> >>>> To allow for emergency disabling in case of wider than expected >>>> breakage, I intend to add a feature for it, and do a 50% field trial on >>>> pre-release channels, though plan to just enable the feature, rather than >>>> do a gradual rollout to stable, given the low usage. >>>> >>>> >>>> Gecko: Positive ( >>>> https://github.com/whatwg/url/pull/619#issuecomment-890826499 >>>> <https://www.chromestatus.com/admin/features/launch/5679790780579840/1?intent=1> >>>> ) >>>> >>> >>> Can you file an official position request? https://bit.ly/blink-signals >>> >> >> Done for Mozilla: >> https://github.com/mozilla/standards-positions/issues/568 >> >> Should I also do this for WebKit as well? They have in process CLs, so >> not sure if it's still needed. >> > > Agree that in-flight patches for WebKit are a sufficient positive signal. > > >> >> >>> >>> >>>> >>>> WebKit: In development (https://bugs.webkit.org/show_bug.cgi?id=228826) >>>> >>>> Web developers: No signals >>>> >>>> Activation >>>> >>>> This breaks anything using one of these domains, and requires migrating >>>> to other hostnames. >>>> >>>> >>>> Security >>>> >>>> None >>>> >>>> >>>> Debuggability >>>> >>>> These will act like any other invalid URL. Behavior is context >>>> dependent. Since this is logic deep within GURL, and GURLs are created in a >>>> great many places, console warnings specifically for this seem not >>>> practical. >>>> >>>> >>>> Is this feature fully tested by web-platform-tests >>>> <https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md> >>>> ?No. Javascript URL construction is tested, but URLs are used in a >>>> great many other places, which don't have test coverage, since DNS lookups >>>> for these domains must succeed in the first place for the tests to be >>>> meaningful. >>>> >>>> Flag name >>>> >>>> Requires code in //chrome?False >>>> >>>> Tracking bughttps://crbug.com/1237032 >>>> >>>> Estimated milestones >>>> DevTrial on desktop 95 >>>> DevTrial on Webview 95 >>>> >>>> Link to entry on the Chrome Platform Status >>>> https://www.chromestatus.com/feature/5679790780579840 >>>> >>>> This intent message was generated by Chrome Platform Status >>>> <https://www.chromestatus.com/>. >>>> >>>> -- >>>> 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 [email protected]. >>>> To view this discussion on the web visit >>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAEK7mvq%2Bfnau%3DE%2BONhe0kr9HOpN84eCpoub84%3DswKzPkrGzi5A%40mail.gmail.com >>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAEK7mvq%2Bfnau%3DE%2BONhe0kr9HOpN84eCpoub84%3DswKzPkrGzi5A%40mail.gmail.com?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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