923067 - Got "NS_ERROR_DOM_BAD_URI: Access to restricted URI denied" error when accessing missing file:/// with Ajax - shouldn't it be "file not found" instead?

Status: RESOLVED WONTFIX

(Core :: DOM: Core & HTML, defect)

Description

[Soledad Penades [:sole] [:spenades]]

Attachment: test case

I am not sure about the reasoning behind throwing that error, but as a developer I'd find it more useful if the browser told me that the file wasn't there, rather than throwing a "restricted URL" exception :-)

Attaching test case to be tried locally.

I also uploaded it but as it's not local it works correctly:
GET http://people.mozilla.org/~spenades/test_cases/local_restricted_url_404/a-file-that-doesnt-exist.txt

http://people.mozilla.org/~spenades/test_cases/local_restricted_url_404/

Comment 1

[Mihai Sucan [:msucan]]

This doesn't seem to be a web console bug. The web console simply displays errors that come from other parts in the browser.

Maybe this is a Core bug?

Comment 2

[Soledad Penades [:sole] [:spenades]]

Probably. I rely on your infinite wisdom to change components to the proper one, because I am very newbie at that--just did my best at guessing :-)

Thanks for reassigning!

Comment 3

[Boris Zbarsky [:bzbarsky]]

So we land in nsPrincipal::CheckMayLoad which calls NS_RelaxStrictFileOriginPolicy.  This can't get the target file, so can't do basic security checks on it (e.g. whether it's a directory), so it returns false.  Then CheckMayLoad returns NS_ERROR_DOM_BAD_URI, which is what the XMLHttpRequest implementation then has to work with...

I don't think it's worth adding special-cases here to make this look like not a permissions check failure, especially because it _is_ a permissions check failure: linking to local files is only allowed if we know certain information about the file, and we can't get that information for nonexistent files.