On Mon, Jan 23, 2023 at 3:00 PM Jun Kokatsu <jkoka...@google.com> wrote:
> Hi All, > > I wanted to provide some updates on outreach I've done last week. > > I manually went through a list of sample sites in the use counter > <https://chromestatus.com/metrics/feature/timeline/popularity/4356>, and > contacted ~10 sites which will be impacted. Among those sites, 3 sites > responded so far. > > 1. onsetapp.com has successfully migrated away from data: URLs in > SVGUseElement. > - Reason for the usage: > > > *"We used them to import elements from SVG sprites, basically an SVG file > containing every icons loaded once at page load as an attempt to improve > performance of the app."* > 2. jobs.nzz.ch are testing the fix in the development pipeline, and > hope to migrate away from data: URLs in SVGUseElement soon. > - Reason for the usage is unsure as it was done a long time ago. > 3. We've reached out to Salesforce contact (thanks Rick!) for > appexchange.salesforce.com. They are trying to find a responsible team > for that subdomain to understand why it was used, and if it can be migrated > away. > > Thanks Jun, that's some good anecdotal evidence that adapting to this breaking change likely isn't too hard for most folks. Despite it being only a couple anecdotes, this increases my confidence. > I've also identified faucet.okp4.network as a false positive, because > they use svgxuse <https://github.com/Keyamoon/svgxuse> as a fallback > mechanism <https://github.com/okp4/ui/pull/433>. > Fascinating. I will wait for sometime so that UKM will reach Beta or Stable, to further > identify impacted origins with high volume of access. > Yeah I think this is the most important next step. With luck we'll find that there's not too much of a long tail and we can succeed in getting a significant drop in usage through outreach. BTW, thank you Daniel for creating a page > <https://dbratell.github.io/svg-use-icons/> with easy to read > alternatives! This was very helpful in the outreach process! > Thanks Daniel! If we proceed with deprecation then perhaps this page should form the basis of a chromium.org blog post on the topic that we can link to from the chromestatus entry that will be referenced in the deprecation warning message. > > Thanks, > > Jun > > > On Thu, Jan 19, 2023 at 3:23 PM Jun Kokatsu <jkoka...@google.com> wrote: > >> On Thu, Jan 19, 2023 at 2:14 PM Rick Byers <rby...@chromium.org> wrote: >> >>> On Thu, Jan 19, 2023 at 1:17 PM Jun Kokatsu <jkoka...@google.com> wrote: >>> >>>> On Thu, Jan 19, 2023 at 9:29 AM Rick Byers <rby...@chromium.org> wrote: >>>> >>>>> Thanks Daniel. I also looked at this page >>>>> <https://appexchange.salesforce.com/#:~:text=Learn%20More-,Sponsored%20Solutions,-Show%20More> >>>>> which >>>>> inlines the same 422 kB long sprite sheet 5 separate times, only to select >>>>> a tiny 422 BYTE SVG out of it each time! In that case, simply inlining the >>>>> desired SVG would save both several MB of network and a lot of >>>>> parse/decode >>>>> time. Perhaps there's an opportunity for a tool at design time which >>>>> unrolls these inlined sprite sheets, like Jun's tool >>>>> <https://data-urls-in-svg-converter.glitch.me/> does? >>>>> >>>>> Rick >>>>> >>>>> On Thu, Jan 19, 2023 at 8:53 AM Daniel Bratell <bratel...@gmail.com> >>>>> wrote: >>>>> >>>>>> Without saying whether it is appropriate to block data urls, I would >>>>>> like to say that doing what the site is doing with icons in data urls is >>>>>> far from the best way to do it. Since there are better ways to accomplish >>>>>> the same output, it's not in itself a use pattern that must be preserved. >>>>>> It is better to either have the icons in a separate file, or if that is >>>>>> unsuitable, have them inline in an invisible svg. I put a quick demo at >>>>>> https://dbratell.github.io/svg-use-icons/ but in short you could have >>>>>> >>>>>> <svg style="display:none"><defs><symbol >>>>>> id="icon1">...</symbol><symbol id="icon2">...</symbol></defs></svg> >>>>>> >>>>>> And then refer to the icons in it with <svg><use >>>>>> xlink:href="#icon1"></svg> or <svg><use xlink:href="#icon2"></svg> >>>>>> That would have cut tens of KB from the cz site source. I checked >>>>>> with fs and thanks to optimizations Blink would not have created a >>>>>> separate >>>>>> svg document for each icon but that was also a risk. >>>>>> >>>>>> (Also curious to the answer to Alex' question) >>>>>> >>>>>> /Daniel >>>>>> >>>>>> On 2023-01-18 17:50, Alex Russell wrote: >>>>>> >>>>>> Per today's API OWNERs meeting, a dumb question: is the XSS risk here >>>>>> largely down to script execution triggered by this pattern? Or non-script >>>>>> content in the inline'd SVG? >>>>>> >>>>>> Sorry, I just noticed that I only replied to Alex yesterday 🙂 >>>> The XSS risk here is mostly about script execution triggered by this >>>> pattern. This includes (but not limited to) inline event handlers and links >>>> with Javascript URLs. >>>> >>> >>> So if we find it's too breaking to disallow this pattern completely, >>> could we instead just disable script execution from within the context of >>> documents resulting from data: URLs in SVGUseAttributes? >>> >> >> Is that solution for Trusted Types or XSS through SVGUseElement in >> general? >> > I was thinking for SVGUseElement in general. > If it is for Trusted Types, it does solve the issue in Chromium for short >> term, but we want other rendering engines to implement Trusted Types as >> well. Does that mean we spec this in Trusted Types that inline event >> handlers from SVGUseElement will be disallowed when enforcing Trusted >> Types? >> One thing I'm not sure about this approach is that each rendering engine >> has differences in supported features inside SVGUseElement. >> > Oh yeah I certainly wouldn't suggest we do anything chromium-specific here. Just that if we decide the web compat challenge of deprecating all data urls is too high, then we could probably get other vendors on board with something more modest and get that fully spec'd and tested. For example, if the <foreignObject> >> <https://developer.mozilla.org/en-US/docs/Web/SVG/Element/foreignObject> >> is supported, then iframes inside foreignObject can have srcdoc, and it can >> contain script tags which are considered "stored" XSS (because the payload >> never goes through DOM APIs), and therefore Trusted Types could be bypassed >> (i.e. script tags are not inline event handlers). But maybe the current >> script element restriction >> <https://www.w3.org/TR/SVG2/struct.html#UseShadowTree:~:text=Within%20a%20use%2Delement%20shadow%20tree%2C%20%E2%80%98script%E2%80%99%20elements%20are%20inert%20(do%20not%20execute)%3B> >> on the use element is enough to apply in child frames too? >> >> If it is for XSS, then as I mentioned, SVG link >> <https://developer.mozilla.org/en-US/docs/Web/SVG/Element/a> with >> Javascript: URL can still trigger XSS (because the script execution is a >> result of navigation, which can happen in the top frame or iframes by >> target attribute). >> >> Long story short, we did consider disabling scripts, but people's >> consensus (1 <https://github.com/mozilla/standards-positions/issues/718> >> , 2 <https://github.com/WebKit/standards-positions/issues/108>, 3 >> <https://github.com/w3c/trusted-types/issues/357#issuecomment-1049761361> >> , 4 <https://bugs.chromium.org/p/chromium/issues/detail?id=1300195#c10>, >> 5 <https://bugs.chromium.org/p/chromium/issues/detail?id=1300195#c11>) >> has been that it's just better to deprecate data: URLs in SVGUseElement. >> > Thanks for those links, I hadn't appreciated how much discussion had gone into the tradeoffs already. I agree that if we can convince ourselves it's not too breaking that this is the best solution. But I see from the discussion that the consensus was based on the assumption that we had already decided the web compat risk was sufficiently low. I'd certainly prefer not to re-open the standards discussion as this solution seems the safest, simplest and most coherent for the platform, but it's good to know what our fallback options are so that we can keep the cost/benefit tradeoffs in mind as we learn more. > Thanks >>>>>> >>>>>> On Tuesday, January 17, 2023 at 10:52:29 PM UTC-8 Jun Kokatsu wrote: >>>>>> >>>>>>> On Tue, Jan 17, 2023 at 11:36 AM Brandon Heenan <bhee...@google.com> >>>>>>> wrote: >>>>>>> >>>>>>>> Thanks for adding me. Yes, this definitely seems like the pattern >>>>>>>> where we'd want a temporary enterprise policy to re-enable support for >>>>>>>> ~3 >>>>>>>> milestones after we remove support by default. >>>>>>>> go/chrome-enterprise-friendly >>>>>>>> <https://goto.google.com/chrome-enterprise-friendly> gets into the >>>>>>>> details of the why, >>>>>>>> https://source.chromium.org/chromium/chromium/src/+/main:docs/enterprise/add_new_policy.md >>>>>>>> is the step-by-step, and the enterprise team is always happy to advise >>>>>>>> as >>>>>>>> well. >>>>>>>> >>>>>>> >>>>>>> Thank you for the details on enterprise policy! I'll make sure to >>>>>>> follow those steps when I plan to remove the feature by default! >>>>>>> >>>>>>>> On Tue, Jan 17, 2023 at 10:51 AM Rick Byers <rby...@chromium.org> >>>>>>>> wrote: >>>>>>>> >>>>>>>>> On Tue, Jan 17, 2023 at 4:48 AM Yoav Weiss <yoavwe...@chromium.org> >>>>>>>>> wrote: >>>>>>>>> >>>>>>>>>> Would it be possible to turn >>>>>>>>>> <https://source.chromium.org/chromium/chromium/src/+/main:components/page_load_metrics/browser/observers/use_counter/ukm_features.cc;l=30?q=ukm%20usecounter&ss=chromium> >>>>>>>>>> the usecounter into a UKM to get a better view of the number of >>>>>>>>>> impacted >>>>>>>>>> origins, beyond just the homepage? >>>>>>>>>> >>>>>>>>> >>>>>>>>> Yeah that could be useful. But we've also got some leads already >>>>>>>>> so getting more leads may not be critical until we follow up on the >>>>>>>>> ones we >>>>>>>>> have. Can we find a developer for one of those sites who will talk to >>>>>>>>> us >>>>>>>>> about where that pattern is coming from in their toolchain and how >>>>>>>>> they'd >>>>>>>>> migrate off it? Having the UKM data will also help in selecting the >>>>>>>>> sites >>>>>>>>> that will have the most impact on our users (and hence our UseCounter >>>>>>>>> stats). Maybe we'll get lucky and find that, despite the long tail, >>>>>>>>> 90% of >>>>>>>>> the usage is from just a few sites we can work with. >>>>>>>>> >>>>>>>> >>>>>>> Added UKM at https://crrev.com/c/4171733. >>>>>>> >>>>>>>> >>>>>>>>> I wonder if this would be a good candidate for a deprecation >>>>>>>>>> trial + enterprise policy. That would solve this injection vector >>>>>>>>>> for the >>>>>>>>>> broader web, while giving impacted folks some more time to move away >>>>>>>>>> from >>>>>>>>>> this pattern. >>>>>>>>>> >>>>>>>>> >>>>>>>>> Good idea. Impacting a large number of small sites is still >>>>>>>>> problematic for a deprecation trial. Just reaching enough to make any >>>>>>>>> change at all is the hard part. Perhaps we can make replacing the >>>>>>>>> usage >>>>>>>>> easier than the overhead of getting an applying an OT token? Still a >>>>>>>>> deprecation trial would probably be useful. Enterprise policy, >>>>>>>>> certainly. +Brandon >>>>>>>>> Heenan <bhee...@google.com> can help advise on that. I'd also >>>>>>>>> advise leaving this enabled for WebView (at least to start), it feels >>>>>>>>> like >>>>>>>>> the sort of chromium rendering quirk we've found Android apps to rely >>>>>>>>> on >>>>>>>>> disproportionately in the past. >>>>>>>>> >>>>>>>>> On Fri, Jan 13, 2023 at 9:11 PM 'Jun Kokatsu' via blink-dev < >>>>>>>>>> blink-dev@chromium.org> wrote: >>>>>>>>>> >>>>>>>>>>> Thank you Rick for the detailed explanation! >>>>>>>>>>> >>>>>>>>>>> On Fri, Jan 13, 2023 at 10:30 AM Rick Byers <rby...@chromium.org> >>>>>>>>>>> wrote: >>>>>>>>>>> >>>>>>>>>>>> Eliminating this makes sense to me given the security benefit. >>>>>>>>>>>> Thank you for pushing it! But it does seem somewhat risky from a >>>>>>>>>>>> web compat >>>>>>>>>>>> perspective. 0.005% is above our "small but non-trivial risk >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.mqfkui78vo5z>" >>>>>>>>>>>> rule of thumb. Here's a bit of an analysis according to our other >>>>>>>>>>>> compat >>>>>>>>>>>> principles <http://bit.ly/blink-compat>: >>>>>>>>>>>> >>>>>>>>>>>> - Severity of breakage >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.u5ya6jvru7dl>: >>>>>>>>>>>> lower given this is likely only about some visualis, but this >>>>>>>>>>>> site <https://jobs.nzz.ch/> is a good example of >>>>>>>>>>>> non-trivial UI breakage. This pattern of putting a >>>>>>>>>>>> base64-encoded SVG into >>>>>>>>>>>> an SVG <use> element with nothing else in the <svg> is weird, >>>>>>>>>>>> isn't it? Why >>>>>>>>>>>> would someone do that rather than just put the SVG in directly, >>>>>>>>>>>> or put the >>>>>>>>>>>> data URL into an img tag? >>>>>>>>>>>> >>>>>>>>>>>> I've looked into that site. And it seems like they are reusing >>>>>>>>>>> a single SVG image (i.e. data: URL SVG image) which contains several >>>>>>>>>>> images, and changing which image should be rendered by combination >>>>>>>>>>> of >>>>>>>>>>> symbol >>>>>>>>>>> <https://developer.mozilla.org/en-US/docs/Web/SVG/Element/symbol> + >>>>>>>>>>> id (which is only possible in use element, and not in img tag). >>>>>>>>>>> Migration >>>>>>>>>>> can be done by hosting the same image in the same-origin endpoint, >>>>>>>>>>> converting it to blob: URL and assigning that to the <use> element, >>>>>>>>>>> or >>>>>>>>>>> inlining each SVG image. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>> Interesting. So could we write a tool which, given the source >>>>>>>>> html, transforms it to simply inline the selected SVG? That would >>>>>>>>> save some >>>>>>>>> bytes too, right? We've found in the past that when we give >>>>>>>>> developers easy >>>>>>>>> tools to trivially adapt their code, then it makes moderate-risk >>>>>>>>> deprecations go quite smoother. I.e. when we get to the point of >>>>>>>>> having a >>>>>>>>> deprecation warning (and report >>>>>>>>> <https://wicg.github.io/deprecation-reporting/>) for the usage, >>>>>>>>> if we can simply say "for most cases we've found you can just run >>>>>>>>> your html >>>>>>>>> through this tool to adapt it automatically", then that would help a >>>>>>>>> LOT in >>>>>>>>> having the comfort to make the breaking change. Someone from the >>>>>>>>> devrel or >>>>>>>>> tooling teams with experience in how developers approach images in >>>>>>>>> practice >>>>>>>>> (eg. +Addy Osmani <ad...@chromium.org>) might be able to advise >>>>>>>>> on a pragmatic and helpful path. >>>>>>>>> >>>>>>>> >>>>>>> I've created a site to convert data: URLs in SVGUseElement to inline >>>>>>> SVG. >>>>>>> https://data-urls-in-svg-converter.glitch.me/ >>>>>>> >>>>>>>> >>>>>>>>>>>> - I don't suppose there's some creative way to allow this >>>>>>>>>>>> specific odd pattern while still getting the security benefit, >>>>>>>>>>>> is there? >>>>>>>>>>>> >>>>>>>>>>>> Unfortunately, no. While we could read the href value of <use> >>>>>>>>>>> elements and convert the data: URL to blob: URL, we won't know if >>>>>>>>>>> the data: >>>>>>>>>>> URL was set by the site owner, or a malicious attacker (through HTML >>>>>>>>>>> injection). So while we could provide such a library, it does not >>>>>>>>>>> provide >>>>>>>>>>> the security benefit that we are seeking. >>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> - Unique sites impacted >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.4k9u8ddizqrq>: >>>>>>>>>>>> Finding a variety of small sites is actually a lot worse than >>>>>>>>>>>> if we had >>>>>>>>>>>> found only a few bigger sites. It means there's probably some >>>>>>>>>>>> common tool >>>>>>>>>>>> or pattern leading different designers/developers to do this >>>>>>>>>>>> and so likely >>>>>>>>>>>> a relatively large number of individuals who would need to be >>>>>>>>>>>> involved in >>>>>>>>>>>> fixing the breakage. Of course our HTTP Archive list of sites >>>>>>>>>>>> is just a >>>>>>>>>>>> subset of who's fully impacted, so if the problem is a >>>>>>>>>>>> long-tail one as it >>>>>>>>>>>> seems, HTTP archive data shows us only the tip of that long >>>>>>>>>>>> tail. >>>>>>>>>>>> - Security >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.iklh96dxj81w>: >>>>>>>>>>>> it's definitely worth taking some comapt risk to reduce XSS >>>>>>>>>>>> surface area. I >>>>>>>>>>>> don't fully understand the threat model though. Is this mainly >>>>>>>>>>>> a risk for >>>>>>>>>>>> sites who are programmatically putting (potentially >>>>>>>>>>>> attacker-controlled) >>>>>>>>>>>> strings into SVGUseElement hrefs? Or are you more worried about >>>>>>>>>>>> cases where >>>>>>>>>>>> the attacker controls the HTML and can take advantage of this >>>>>>>>>>>> oddity in the >>>>>>>>>>>> platform on any normal site? I'm just trying to gauge the >>>>>>>>>>>> magnitude of the >>>>>>>>>>>> security benefit here to weigh it against the comapt risk, any >>>>>>>>>>>> help is >>>>>>>>>>>> appreciated. >>>>>>>>>>>> >>>>>>>>>>>> We are worried about both (i.e. Server-side injection and DOM >>>>>>>>>>> XSS). The fact that this has led to several browser security feature >>>>>>>>>>> bypasses (e.g. Sanitizer API and Trusted Types) suggests that it's >>>>>>>>>>> not a >>>>>>>>>>> commonly known XSS sink, and therefore we believe that it's common >>>>>>>>>>> for >>>>>>>>>>> security mechanisms (e.g. sanitizers, linters) to miss this odd >>>>>>>>>>> feature. >>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> - Ease of adaptation >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.x5bhg5grhfeo>: >>>>>>>>>>>> seems like it should be easy to use an alternative, at least >>>>>>>>>>>> for these >>>>>>>>>>>> image cases, but I guess it's hard to say without knowing why >>>>>>>>>>>> people are >>>>>>>>>>>> doing this. Is there perhaps some website design tool which is >>>>>>>>>>>> generating >>>>>>>>>>>> this and will need to change? >>>>>>>>>>>> >>>>>>>>>>>> I think it is easy to migrate by hosting the same image to the >>>>>>>>>>> same-origin endpoint. However, I do understand that it's just less >>>>>>>>>>> work to >>>>>>>>>>> use data: URL than using same-origin image or blob: URL. >>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> - Interop >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.4hjbxw7513sw>: >>>>>>>>>>>> The fact that this doesn't work in Safari is a vote in favor of >>>>>>>>>>>> breaking it >>>>>>>>>>>> in chromium to achieve interop. It does work in Firefox though. >>>>>>>>>>>> >>>>>>>>>>>> For the interop, it's best to use a same-origin URL or blob: >>>>>>>>>>> URL. And since both Mozilla and Webkit are supportive, I believe >>>>>>>>>>> it's >>>>>>>>>>> positive. >>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>>> - Standards conformance >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.xcsa26ortrmi>: >>>>>>>>>>>> This is allowed by spec today, so breaking it requires some >>>>>>>>>>>> more diligence >>>>>>>>>>>> >>>>>>>>>>>> Note that the PR <https://github.com/w3c/svgwg/pull/901> to >>>>>>>>>>> SVG spec got merged. >>>>>>>>>>> >>>>>>>>>> >>>>>>>>> Right, yes, sorry. What I meant was we took the initiative to make >>>>>>>>> a breaking change to long established behavior - IMHO that makes the >>>>>>>>> bar >>>>>>>>> higher than if Chrome had just had a bug in allowing something that >>>>>>>>> was >>>>>>>>> never spec'd or allowed by other browsers. Still I think we can use >>>>>>>>> this >>>>>>>>> positively in our outreach - say something like "the spec has changed >>>>>>>>> to >>>>>>>>> not allow this, all the major browser engines agree that for security >>>>>>>>> reasons it should be disallowed. It already doesn't work in Safari and >>>>>>>>> other WebKit browsers, we want to help you fix your site to work in >>>>>>>>> all >>>>>>>>> browsers". >>>>>>>>> >>>>>>>>>> >>>>>>>>>>>> - Enterprise >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.axcg738lzcs9>: >>>>>>>>>>>> Being broken in Safari is an indication the risk will be higher >>>>>>>>>>>> in >>>>>>>>>>>> enterprise software which is often chromium-only. We may need >>>>>>>>>>>> to go through >>>>>>>>>>>> the enterprise breaking change process >>>>>>>>>>>> <https://www.chromium.org/developers/enterprise-changes/>. >>>>>>>>>>>> - Outreach >>>>>>>>>>>> >>>>>>>>>>>> <https://docs.google.com/document/d/1RC-pBBvsazYfCNNUSkPqAVpSpNJ96U8trhNkfV0v9fk/edit#heading=h.t9ade4ywppcg>: >>>>>>>>>>>> Given the relatively high usage, if we want to proceed with >>>>>>>>>>>> this plan I >>>>>>>>>>>> think this is the main opportunity for mitigations. Can we try >>>>>>>>>>>> contacting >>>>>>>>>>>> some of these sites we've identified to understand why they're >>>>>>>>>>>> using this >>>>>>>>>>>> pattern? Is there a tool generating this pattern which we can >>>>>>>>>>>> get updated >>>>>>>>>>>> before we make the change? I think we'd need a blog post >>>>>>>>>>>> capturing what >>>>>>>>>>>> we've learned from talking with a few customers who have done >>>>>>>>>>>> this and how >>>>>>>>>>>> they fixed it for their UI design flow. >>>>>>>>>>>> >>>>>>>>>>>> Sorry it's not looking to be an easy decision, but I hope this >>>>>>>>>>>> gives you some ideas for how we might be able to reduce the risk >>>>>>>>>>>> to a point >>>>>>>>>>>> that we could proceed. WDYT? >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>>> Yes, it sounds good to me! I will check what has to be done and >>>>>>>>>>> do those step by step 🙂 >>>>>>>>>>> >>>>>>>>>> >>>>>>>>> Ok, good luck! Sorry this isn't as straightforward as a clear >>>>>>>>> recipe. But if we can get a couple developers telling us they were >>>>>>>>> easily >>>>>>>>> able to fix their issue by using a tool or straightforward >>>>>>>>> instructions we >>>>>>>>> can point other to, and we see the UseCounter drop significantly (say >>>>>>>>> by >>>>>>>>> half or so) without major new red flags, then I'd personally be OK >>>>>>>>> approving a removal attempt. Of course it's common to learn during >>>>>>>>> beta >>>>>>>>> (or, worst case, upon stable release) that the compat issue is worse >>>>>>>>> than >>>>>>>>> we thought and so the change needs to be reverted (or flagged off with >>>>>>>>> finch) in a hurry. But I think we've learned a lot over the years >>>>>>>>> about how >>>>>>>>> to predict and avoid that failure mode. Let me know if I can do >>>>>>>>> anything >>>>>>>>> else to help, happy to meet to brainstorm further for example. Good >>>>>>>>> luck! >>>>>>>>> >>>>>>>> >>>>>>> Thanks! I'll start outreach for a couple of sites we already know >>>>>>> are affected, and go from there! >>>>>>> >>>>>>>> >>>>>>>>> >>>>>>>>>>>> Rick >>>>>>>>>>>> >>>>>>>>>>>> On Thu, Jan 12, 2023 at 3:11 PM 'Jun Kokatsu' via blink-dev < >>>>>>>>>>>> blink-dev@chromium.org> wrote: >>>>>>>>>>>> >>>>>>>>>>>>> On Thu, Jan 12, 2023 at 10:44 AM Mike Taylor < >>>>>>>>>>>>> miketa...@chromium.org> wrote: >>>>>>>>>>>>> >>>>>>>>>>>>>> On 1/11/23 6:49 PM, 'Jun Kokatsu' via blink-dev wrote: >>>>>>>>>>>>>> >>>>>>>>>>>>>> Contact emails >>>>>>>>>>>>>> >>>>>>>>>>>>>> jkoka...@google.com >>>>>>>>>>>>>> >>>>>>>>>>>>>> Specification >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> https://svgwg.org/svg2-draft/struct.html#UseElementHrefAttribute >>>>>>>>>>>>>> >>>>>>>>>>>>>> https://github.com/w3c/svgwg/pull/901/files >>>>>>>>>>>>>> >>>>>>>>>>>>>> Summary >>>>>>>>>>>>>> >>>>>>>>>>>>>> Assigning a data: URL in SVGUseElement can cause XSS. And >>>>>>>>>>>>>> this also led to a Trusted Types bypass. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Therefore, we plan to deprecate and remove support for it. >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Blink component >>>>>>>>>>>>>> >>>>>>>>>>>>>> Blink>SVG >>>>>>>>>>>>>> <https://bugs.chromium.org/p/chromium/issues/list?q=component:Blink%3ESVG> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Motivation >>>>>>>>>>>>>> >>>>>>>>>>>>>> Assigning an attacker controlled string to SVGUseElement.href >>>>>>>>>>>>>> causes XSS and a Trusted Types bypass >>>>>>>>>>>>>> <https://github.com/w3c/trusted-types/issues/357> because of >>>>>>>>>>>>>> data: URLs. If we fix this bug by requiring TrustedScriptURL >>>>>>>>>>>>>> assignment to >>>>>>>>>>>>>> SVGUseElement.href under Trusted Types enforcement, many sites >>>>>>>>>>>>>> would need >>>>>>>>>>>>>> to refactor code (even for same-origin URL or Blob URL >>>>>>>>>>>>>> assignment). >>>>>>>>>>>>>> >>>>>>>>>>>>>> Since Webkit does not support data: URLs in SVGUseElement and >>>>>>>>>>>>>> both Mozilla and Webkit are supportive for the removal, we think >>>>>>>>>>>>>> that >>>>>>>>>>>>>> removing support for data: URLs in SVGUseElement is the right >>>>>>>>>>>>>> way to solve >>>>>>>>>>>>>> this problem. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Additionally, data: URLs can only trigger script execution in >>>>>>>>>>>>>> script loaders such as HTMLScriptElement.src or dynamic >>>>>>>>>>>>>> import >>>>>>>>>>>>>> <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/import>. >>>>>>>>>>>>>> However, SVGUseElement is an exception to this, which also >>>>>>>>>>>>>> caused a >>>>>>>>>>>>>> bypass >>>>>>>>>>>>>> <https://bugs.chromium.org/p/chromium/issues/detail?id=1306450#c10> >>>>>>>>>>>>>> in the Sanitizer API. We believe that this also led to several >>>>>>>>>>>>>> other bugs >>>>>>>>>>>>>> in sanitizers and linters missing a check for this special case. >>>>>>>>>>>>>> >>>>>>>>>>>>>> The usage >>>>>>>>>>>>>> <https://chromestatus.com/metrics/feature/timeline/popularity/4356> >>>>>>>>>>>>>> of data: URLs in SVGUseElement is about 0.005%. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Digging into the HTTP Archive shows usages in ~50 sites. >>>>>>>>>>>>>> There are 2 major sites (slickdeals.net and hunter.104.com.tw) >>>>>>>>>>>>>> which use data: URLs in SVGUseElement. >>>>>>>>>>>>>> >>>>>>>>>>>>>> The use in slickdeals.net is invisible (i.e. used in the >>>>>>>>>>>>>> footer but doesn't appear), and hunter.104.com.tw is using >>>>>>>>>>>>>> it for a single icon in the footer (which is already broken when >>>>>>>>>>>>>> rendered >>>>>>>>>>>>>> in Webkit). Rest of the usages seems to be in individual small >>>>>>>>>>>>>> sites. >>>>>>>>>>>>>> >>>>>>>>>>>>>> I poked around the 10 sample sites at the bottom of the use >>>>>>>>>>>>>> counter: >>>>>>>>>>>>>> >>>>>>>>>>>>>> https://www.aspareanord.it/, https://www.umbria.camcom.it, >>>>>>>>>>>>>> https://www.bisenzio.it/, https://www.comune.vernio.po.it/, >>>>>>>>>>>>>> https://appaltinnovativi.gov.it/, https://www.gdf.gov.it/, >>>>>>>>>>>>>> https://www.us.schott.com/, https://shop.wavin.com/, >>>>>>>>>>>>>> https://jobs.nzz.ch/, https://www.learnapp.com/ >>>>>>>>>>>>>> >>>>>>>>>>>>>> For the 6 Italian sites (I guess the same agency made them?), >>>>>>>>>>>>>> the right arrow icon next to "Vedi" would disappear. For a site >>>>>>>>>>>>>> like >>>>>>>>>>>>>> https://jobs.nzz.ch - there's a number of visually >>>>>>>>>>>>>> significant design icons that would be gone towards the bottom >>>>>>>>>>>>>> (and yes, it >>>>>>>>>>>>>> looks sort of broken today in Safari). >>>>>>>>>>>>>> >>>>>>>>>>>>>> It's not the end of the world, looking at these 10 sites, but >>>>>>>>>>>>>> I wonder how a developer would know how to fix this. Have you >>>>>>>>>>>>>> considered a >>>>>>>>>>>>>> DevTools issue? >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> Thank you for the suggestion! Yes, I do plan to follow Deprecation >>>>>>>>>>>>> steps >>>>>>>>>>>>> <https://chromium.googlesource.com/chromium/src/+/HEAD/third_party/blink/renderer/core/frame/deprecation/README.md> >>>>>>>>>>>>> and >>>>>>>>>>>>> add a Devtools issue 🙂 >>>>>>>>>>>>> >>>>>>>>>>>>>> Initial public proposal >>>>>>>>>>>>>> >>>>>>>>>>>>>> TAG review >>>>>>>>>>>>>> >>>>>>>>>>>>>> TAG review status >>>>>>>>>>>>>> >>>>>>>>>>>>>> Not applicable. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Because this intent removes part of a feature, and it is >>>>>>>>>>>>>> already shipped in Webkit (i.e. never supported). >>>>>>>>>>>>>> >>>>>>>>>>>>>> Risks >>>>>>>>>>>>>> >>>>>>>>>>>>>> Interoperability and Compatibility >>>>>>>>>>>>>> >>>>>>>>>>>>>> Gecko: Positive >>>>>>>>>>>>>> <https://github.com/mozilla/standards-positions/issues/718> >>>>>>>>>>>>>> >>>>>>>>>>>>>> WebKit: Positive >>>>>>>>>>>>>> <https://github.com/WebKit/standards-positions/issues/108> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Web developers: No signals >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Debuggability >>>>>>>>>>>>>> >>>>>>>>>>>>>> Is this feature fully tested by web-platform-tests >>>>>>>>>>>>>> <https://chromium.googlesource.com/chromium/src/+/main/docs/testing/web_platform_tests.md> >>>>>>>>>>>>>> ? >>>>>>>>>>>>>> >>>>>>>>>>>>>> Yes <https://github.com/web-platform-tests/wpt/pull/37511> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Flag name >>>>>>>>>>>>>> >>>>>>>>>>>>>> RemoveDataUrlInSvgUse >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Requires code in //chrome? >>>>>>>>>>>>>> >>>>>>>>>>>>>> False >>>>>>>>>>>>>> >>>>>>>>>>>>>> Tracking bug >>>>>>>>>>>>>> >>>>>>>>>>>>>> https://bugs.chromium.org/p/chromium/issues/detail?id=1300195 >>>>>>>>>>>>>> >>>>>>>>>>>>>> Estimated milestones >>>>>>>>>>>>>> >>>>>>>>>>>>>> Deprecate for 2 milestones, then remove depending on >>>>>>>>>>>>>> breakages. >>>>>>>>>>>>>> >>>>>>>>>>>>>> Can you say more about what the deprecation looks like (i.e., >>>>>>>>>>>>>> blog post, deprecation reports, devtools issue, etc)? >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> Link to entry on the Chrome Platform Status >>>>>>>>>>>>>> >>>>>>>>>>>>>> https://chromestatus.com/feature/5128825141198848 >>>>>>>>>>>>>> >>>>>>>>>>>>>> This intent message was generated by Chrome Platform Status >>>>>>>>>>>>>> <https://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 blink-dev+unsubscr...@chromium.org. >>>>>>>>>>>>>> To view this discussion on the web visit >>>>>>>>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOWKMF6VXw7jmQoZM47i3ybzn%3D5Pc4mw26Khv9U9aP_UzBt-dg%40mail.gmail.com >>>>>>>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOWKMF6VXw7jmQoZM47i3ybzn%3D5Pc4mw26Khv9U9aP_UzBt-dg%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>>>>>>>> . >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> -- >>>>>>>>>>>>> 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 on the web visit >>>>>>>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOWKMF5KQOG5R8baUM41T4fR01QbGFjvvEsf629h%2BzASCn_F0Q%40mail.gmail.com >>>>>>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOWKMF5KQOG5R8baUM41T4fR01QbGFjvvEsf629h%2BzASCn_F0Q%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>>>>>>> . >>>>>>>>>>>>> >>>>>>>>>>>> -- >>>>>>>>>>> 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 on the web visit >>>>>>>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOWKMF65KcSCkzVupRw4n8ZG%3DKKbG5GY62HzwNSZW4Z78ZYd_w%40mail.gmail.com >>>>>>>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/CAOWKMF65KcSCkzVupRw4n8ZG%3DKKbG5GY62HzwNSZW4Z78ZYd_w%40mail.gmail.com?utm_medium=email&utm_source=footer> >>>>>>>>>>> . >>>>>>>>>>> >>>>>>>>>> -- >>>>>> 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 on the web visit >>>>>> https://groups.google.com/a/chromium.org/d/msgid/blink-dev/d63c3823-20b6-457c-bff9-f85429421bf0n%40chromium.org >>>>>> <https://groups.google.com/a/chromium.org/d/msgid/blink-dev/d63c3823-20b6-457c-bff9-f85429421bf0n%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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