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Re: Clipboard API: remove dangerous formats from mandatory data types

From: Daniel Cheng <dcheng@google.com>
Date: Thu, 25 Jun 2015 17:57:03 +0000
Message-ID: <CAF3XrKqNN7BA-0D3twamHBb1WwDzvKMvkcqLeV1BZxKgyGqE+w@mail.gmail.com>
To: Florian Bösch <pyalot@gmail.com>
Cc: Wez <wez@google.com>, Hallvord Reiar Michaelsen Steen <hsteen@mozilla.com>, public-webapps <public-webapps@w3.org>
That's the case today already, and I haven't seen this happening.


On Thu, Jun 25, 2015 at 10:48 AM Florian Bösch <pyalot@gmail.com> wrote:

> I'm sure you're aware that you can encode any binary blob as UTF-8
> text/plain. If you don't support application/octet-stream, then that just
> becomes the "dumping ground".
> On Thu, Jun 25, 2015 at 7:39 PM, Daniel Cheng <dcheng@google.com> wrote:
>> No UA supports it today. No UA is likely to support it anytime soon.
>> Daniel
>> On Thu, Jun 25, 2015 at 10:38 AM Florian Bösch <pyalot@gmail.com> wrote:
>>> Yet you restrict mime-types AND you support application/octet-stream?
>>> On Thu, Jun 25, 2015 at 7:34 PM, Daniel Cheng <dcheng@google.com> wrote:
>>>> For reasons I've already mentioned, this isn't going to happen because
>>>> there is no so-called "dumping ground".
>>>> No one is going to risk their paste turning into thousands of lines of
>>>> gibberish because they tried to stuff binary data in text/plain.
>>>> Daniel
>>>> On Thu, Jun 25, 2015 at 8:23 AM Florian Bösch <pyalot@gmail.com> wrote:
>>>>> No, what I'm saying is that if you restrict mime types (or don't
>>>>> explicitly prohibit such restriction), but require
>>>>> application/octet-stream, that application/octet-stream becomes the
>>>>> "undesirable mime-type" dumping ground. And that would be bad because that
>>>>> makes it much harder for applications to deal with content. But if that's
>>>>> the only way UAs are going to act, then applications will work around that
>>>>> by using elaborate guessing code based on magic bytes, and perhaps some
>>>>> application developers will use their own mime-type annotation pretended to
>>>>> the octet-stream.
>>>>> If you inconvenience people, but don't make it impossible to work
>>>>> around the inconvenience, then people will work around the inconvenience.
>>>>> It can't be the intention to encourage them work around it. So you've got
>>>>> to either not inconvenience them, or make working around impossible.
>>>>> On Thu, Jun 25, 2015 at 5:07 PM, Wez <wez@google.com> wrote:
>>>>>> Florian, you keep referring to using application/octet-stream -
>>>>>> that's not a format that all user agents support (although the spec says
>>>>>> they should ;), nor is there any mention in the spec of what it means to
>>>>>> place content on the clipboard in that format (given that platform native
>>>>>> clipboards each have their own content-type annotations).
>>>>>> So it sounds like you're saying we should also remove
>>>>>> application/octet-stream as a mandatory format?
>>>>>> On Thu, 25 Jun 2015 at 15:55 Florian Bösch <pyalot@gmail.com> wrote:
>>>>>>> It's very simple. Applications need to know what's in the clipboard
>>>>>>> to know what to do with it. There is also a vast variety of things that
>>>>>>> could find itself in the clipboard in terms of formats, both formal and
>>>>>>> informal. Mime types are one of these things that applications would use to
>>>>>>> do that.
>>>>>>> If a UA where to restict what mime type you can put into the
>>>>>>> clipboard, that forces the clipboard user to use application/octet-stream.
>>>>>>> And in consequence, that forces any such-willing application to forgoe the
>>>>>>> mime-type information from the OS'es clipboard API and figure out what's in
>>>>>>> it from the content. In turn this would give rise to another way to markup
>>>>>>> mime-types in-line with the content. And once you've forced such ad-hoc
>>>>>>> solutions to emerge for meddling with what people can put in the clipboard,
>>>>>>> you'll have no standing to put that geenie back in the bottle, again,
>>>>>>> relevant XKCD quote omitted.
>>>>>>> On Thu, Jun 25, 2015 at 4:48 PM, Wez <wez@google.com> wrote:
>>>>>>>> You've mentioned "resorting to application/octet-stream" several
>>>>>>>> times in the context of this discussion, where AFAICT the spec actually
>>>>>>>> only describes using it as a fall-back for cases of file references on the
>>>>>>>> clipboard for which the user agent is unable to determine the file type.
>>>>>>>> So IIUC you're suggesting that user agents should implement
>>>>>>>> "application/octet-stream" (as is also mandated by the spec, albeit without
>>>>>>>> a clear indication of what it means in this context) by putting the content
>>>>>>>> on the clipboard as an un-typed file?
>>>>>>>> Again, I'm unclear as to what the alternative is that you're
>>>>>>>> proposing?
>>>>>>>> On Thu, 25 Jun 2015 at 15:27 Florian Bösch <pyalot@gmail.com>
>>>>>>>> wrote:
>>>>>>>>> Surely you realize that if the specification where to state to
>>>>>>>>> only "safely" expose data to the clipboard, this can only be interpreted to
>>>>>>>>> deny any formats but those a UA can interprete and deem well-formed. If
>>>>>>>>> such a thing where to be done, that would leave any user of the clipboard
>>>>>>>>> no recourse but to resort to "application/octett-stream" and ignore any
>>>>>>>>> other metadata as the merry magic header guessing game gets underway. For
>>>>>>>>> all you'd have achieved was to muddle any meaning of the mime-type and
>>>>>>>>> forced applications to work around an unenforceable restriction.
>>>>>>>>> On Thu, Jun 25, 2015 at 3:21 PM, Wez <wez@google.com> wrote:
>>>>>>>>>> And, again, I don't see what that has to do with whether the spec
>>>>>>>>>> mandates that user agents let apps place JPEG, PNG or GIF directly on the
>>>>>>>>>> local system clipboard. The spec doesn't currently mandate OpenEXR be
>>>>>>>>>> supported, so it's currently up to individual user agents to decide whether
>>>>>>>>>> they can support that format safely.
>>>>>>>>>> On Thu, 25 Jun 2015 at 14:16 Florian Bösch <pyalot@gmail.com>
>>>>>>>>>> wrote:
>>>>>>>>>>> On Thu, Jun 25, 2015 at 3:13 PM, Wez <wez@google.com> wrote:
>>>>>>>>>>>> I think there's obvious value in support for arbitrary
>>>>>>>>>>>> content-specific formats, but IMO the spec should at least give guidance on
>>>>>>>>>>>> how to present the capability in a safe way.
>>>>>>>>>>> Which is exactly the core of my question. If you intend to make
>>>>>>>>>>> it say, safe to put OpenEXR into the clipboard (as opposed to letting an
>>>>>>>>>>> app just put any bytes there), the UA has to understand OpenEXR. Since I
>>>>>>>>>>> don't see how the UA can understand every conceivable format in existence
>>>>>>>>>>> both future and past, I don't see how that should work.
Received on Thursday, 25 June 2015 17:57:40 UTC

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