Last modified: 2014-10-15 08:41:05 UTC
Obviously the <image /> element is disabled, but it should be stripped, or at
least alert the user to the problem, as many users don't know why their SVGs
<image> is supported, but only for embedded data: urls.
I don't understand:
http://en.wikipedia.org/wiki/Image:Map_of_USA_with_state_names.svg failed to
render the first version, the new version works and the only change was the that
I removed the <image /> element.
Let's look at that <image>:
Notice how the url it uses to reference the image resource is a
relative path, *not* an embedded data: url. It refers to an external
1) Is not allowed by our security policy on the renderer.
2) Wouldn't work anyway since the referenced file wouldn't be there.
The bug isn't that the <image> doesn't work, but that it fails silently. It
should either strip disallowed image elements then render, or alert the user to
the violation of the security policy, so they can fix the image.
Yes, that's why the bug hasn't been closed. :)
You asked why a particular image failed.
(In reply to comment #5)
> Yes, that's why the bug hasn't been closed. :)
> You asked why a particular image failed.
Ah, I was just giving it as an example, I though you were disagreeing with me
with your first comment.
I agree that there should be an error message on the description page. Or, even
better, this should be detected on upload, and the image rejected.
Just to confirm:
1) data: URLs _ARE_ allowed and supported in the svg image uploads + rasterization to PNGs that happen on wikimedia?
2) do you scrub data: URLs to ensure that someone hasn't injected another SVG image (with potentially malicious script)?
If the answer is yes to both the above questions, then a potential solution is to update Inkscape so that upon importing a raster image, the user is presented with 3 options: a) embed raster as base64 data:, b) reference local file, c) reference a foreign URL - with sufficient explanations for these three options that a newbie can understand (i.e. "choose option a if you are uploading this file to wikipedia or openclipart")
If I get some feedback here I can open a bug and help push it along for Inkscape (if it hasn't been opened already - if there is an open bug, please link to it here).
FYI, I have finally opened <a href="https://bugs.launchpad.net/inkscape/+bug/366993">Bug 366993</a> against Inkscape for this issue.
Assigning SVG bugs to Ariel -- need a cleanup pass to see what's fixed up by a librsvg upgrade, what can be resolved with fixes to our font configuration, what can be fixed on our end, and what still needs to be pushed upstream.
Say, I can't actually look at the launchpad bug to see what's up, it's marked private... Jeff, can you do anything about that?
Data URIs _should_ currently work fine; at the moment we implement the restriction against external images by patching librsvg so it literally can't load external resources.
To generalize it via an upload-time check we would indeed want to be able to decode sub-SVG images to check for additional external resources in them; that's a detail I hadn't thought of earlier. :) Still shouldn't be absurdly hard to implement. I'm adding bug 7645 "Validate SVG content" as a dep for this...
And yes, would be very happy if Inkscape would start defaulting to embedding rasters when you add them!
Although the <image> element is disabled for thumbnailing, if the user clicks on the thumbnail to enlarge the image, or is given a link to an image, the <image> element is still present.
As SVG's are rendered in firefox, an image with a "xlink:href" to a malicious image file would still go through. Or at least the user's IP would be revealed.
As an example, see http://upload.wikimedia.org/wikipedia/commons/archive/9/9b/20100517130343!Kyokuryu-kai.svg in which you can see the google logo in the background. This is done by adding
All SVGs with "xlink:href" should be marked with some type of warning, or the "xlink:href" stripped or commented out.
There is now an SVGParser in SVGMetadataExtractor.
I guess we could switch the SVG upload filter to this new mediahandler filter and have it look for xlink:href uri's. We could then warn when a file should not be uploaded. It's not hard to do I guess..
giving SVG bugs back to the pool.
Switching to Wikimedia/SVG Rendering component.
Currently the image-tag get stripped, which made the SVG useless (upload). So I recommend to made a big warning (as reported on Commons: VP).