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

From: Florian Bösch <pyalot@gmail.com>
Date: Thu, 25 Jun 2015 19:48:01 +0200
Message-ID: <CAOK8ODgp-AZAwCdJ8xH2oObcLFx815gXS+3P1rTuMi+GvFT94g@mail.gmail.com>
To: Daniel Cheng <dcheng@google.com>
Cc: Wez <wez@google.com>, Hallvord Reiar Michaelsen Steen <hsteen@mozilla.com>, public-webapps <public-webapps@w3.org>
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 17:48:30 UTC

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