[whatwg] Sandboxed IFrames and downloads.
ian at hixie.ch
Wed Aug 7 16:27:02 PDT 2013
On Sat, 2 Feb 2013, Mike West wrote:
> It's currently possible to force a download by serving a file with a
> "Content-Disposition: attachment; filename=..." header. Notably, this
> mechanism can be used to download a file with minimal user interaction
> by including the resource to be downloaded in an IFrame. This holds even
> for sandboxed IFrames, as demonstrated by
> http://lcamtuf.coredump.cx/sandboxed.html (clicking that link will
> download a file, fair warning).
Note that this is an implementation choice. A browser could display an
inline user interface (e.g. a button in the page, similar to network error
pages) or floating user interface (e.g. a dialog, infobar, or download
bar) offering the file for download, rather than forcing the download.
> It seems consistent with the general thought behind the `sandbox`
> attribute that it should control downloads as well as the bits it
> already locks down. I'd propose adjusting the spec to include a
> sandboxed downloads flag, which, when present, would block all downloads
> from inside the frame (or, perhaps only require user confirmation?).
> This restriction could be lifted via an 'allow-downloads' keyword, if
> present in the sandbox attribute's token list.
I don't really understand why even without a sandbox attribute, a page
should be allowed to force a download.
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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