Hey everyone, >From looking at use counters for these cases, cross-top-level-site Blob URL navigations that would have noopener set as part of this change are seen on 0.0004% of page loads. Note that this is calculated from data from pre-stable channels and could change when looking at Stable data, but it seems unlikely to change by orders of magnitude.
For cross-partition Blob URL fetches, these occur on 0.21% of page loads, but from digging into this more and from looking at UMA data, at least 83% of those cross-partition Blob URL fetches are guaranteed to be blocked today because they are also cross-origin, and only ~21% of UMA-enabled clients reported at least one cross-partition fetch that wasn't guaranteed to be blocked. It's likely that the remaining 17% of cross-partition Blob URL fetches are cross-origin as well and would already be blocked, but our current use counter / metrics implementations don't provide a way to gauge this. More details on this analysis can be found at: https://crbug.com/387655548#comment2 Overall I think the use counter metrics + supporting UMA data support moving forward with this change, as does the fact that Firefox and Safari have already implemented similar functionality. If there is breakage as a result of this, we do have an enterprise policy to disable it, we'll have a chrome://flags entry so that users can disable it, and we'll have a Finch feature flag as a killswitch for any cases of widespread, significant breakage. Regarding formal signals from Gecko and Webkit, we opened one from Gecko but haven't heard anything: https://github.com/mozilla/standards-positions/issues/1151. For WebKit, we reached out regarding whether we should open one and they mentioned they didn't think we needed to, given that we plan to implement what the functionality they have already, just using sites instead of origins. -Andrew On Thu, Dec 12, 2024 at 12:35 PM Andrew Williams <awil...@chromium.org> wrote: > Thanks Domenic, we've landed a change to remove .tentative from the test > file names: > https://chromium-review.googlesource.com/c/chromium/src/+/5967596 > > Gregg, IIUC "top-level->iframe(blob-from-top-level)" means the top-level > creates a blob URL and then creates an iframe where the src is that blob > URL. Similarly, "top-level->iframe(3rd-party)->iframe(blob-from-3rd-party)" > means that the 3rd-party iframe creates a blob URL and then creates an > iframe where the src is that blob URL. Neither of those cases will be > affected by this change. > > Daniel, thanks for the feedback. We will collect use counts on this and > report back once the data is available (should be around mid-February). In > the meantime, we will request formal signals from Gecko and WebKit as you > recommended. > > On the topic of alignment across browsers, the I2S mentions that all > navigations will remain partitioned only by frame origin, but I learned > recently that Safari and Firefox partition subframe navigations (like using > a blob URL as the src of an iframe) by storage key / the top-level as well > (and this is what was originally proposed in > https://github.com/w3c/FileAPI/issues/153). It's only top-level > navigations that remain partitioned only by frame origin. Our > implementation will follow suit. I'll update the Chrome Status description > accordingly. > > -Andrew > > On Wed, Dec 11, 2024 at 11:38 AM Daniel Bratell <bratel...@gmail.com> > wrote: > >> After discussing this on the API OWNER meeting I have a few questions and >> suggestions. >> >> My main concern is that we don't have full understanding of the >> compatibility risk. We believe this is rare, but do we have any hard data >> to confirm that? If not, would it be possible to add a targetted use >> counter that counts the cases where a page tries to use a broken blob? >> >> I think you should also request formal signals from Gecko and WebKit >> since this is not exactly what they have done. It seems from what you write >> that we're getting something very slightly different (which also means that >> what seems to work for them might still break in Chromium). >> >> /Daniel >> On 2024-12-10 03:29, Domenic Denicola wrote: >> >> LGTM1, nice work on all the spec changes here! >> >> Please send a web platform tests PR to remove the .tentative.html from >> the test filenames. >> >> On Tue, Dec 10, 2024 at 10:49 AM Gregg Tavares <g...@chromium.org> wrote: >> >>> Sorry if I'm not up on all of the latest. I have several sites that use >>> blobs in iframes to implement user code execution (think JSFiddle/Codepen). >>> Do I need to be worried? >>> >>> Some use top-level->iframe(blob-from-top-level). Others use >>> top-level->iframe(3rd-party)->iframe(blob-from-3rd-party) >>> >>> They all currently work across browsers so I'm guessing I don't need to >>> worry if Firefox and Safari already implement this. >>> >>> -- >> 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/CAM0wra8377qyjY1fv99%2BnDhJZjWN8j9CdGFLsuwrZVyHJYwUMg%40mail.gmail.com >> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAM0wra8377qyjY1fv99%2BnDhJZjWN8j9CdGFLsuwrZVyHJYwUMg%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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