792955 - Build file upload filter

Status: RESOLVED FIXED

(developer.mozilla.org :: Security, defect)

Description

[John Karahalis [:openjck]]

Based on the decisions that are shared in the following page, implement a file upload filter.

https://wiki.mozilla.org/MDN/Development/Features/File_upload_filter

Comment 1

[James Bennett [:ubernostrum]]

A proof of concept for discussion is in this pull request:

https://github.com/mozilla/kuma/pull/629

Uses a whitelist, configured through constance (so editable in admin for easy tweaking) to control the set of allowed types.

Comment 2

[Luke Crouch [:groovecoder]]

cc'ing docs team to look over https://github.com/mozilla/kuma/pull/638/files#L3R1012 and tell us which file types should be included so we don't break stuff.

Comment 3

[Jeremie Patonnier :Jeremie]

image/svg+xml
text/html

:)

Comment 4

[Jean-Yves Perrier [:teoli]]

Noob question: that doesn't concern already-loaded files, only the new upload?

Comment 5

[Luke Crouch [:groovecoder]]

:teoli : correct, but we will probably use the same white-list of file-types for other things in the future. so we need to get it right for both existing files and new files.

Comment 6

[Jean-Yves Perrier [:teoli]]

In fact, I would like to clean these existing files because some types look really weird (Word documents, x-trash documents, even a Wordperfect I think). I suspect that some of these documents are just residue of old spamming.

The first step to achieve this is to prevent new strange files to be uploaded without us knowing it.
The second step would be to review these strange documents (and likely to get rid of them for more open or at least appropriate format).


Finally, I prefer to be restrictive first, and to open progressively. (We don't upload new types of files every day so it won't be something to PR every day.)

-- 
Jean-Yves

Comment 7

[Luke Crouch [:groovecoder]]

Okay, so the initial list should be:

image/gif
image/jpeg
image/png
image/svg+xml
text/html

And that's it?

Comment 8

[[github robot]]

Commits pushed to master at https://github.com/mozilla/kuma

https://github.com/mozilla/kuma/commit/28b62e1eb8b8b3943b3e9d4a97ddf5e353a8c0c2
Fix bug 792955: Build file upload filter

This adds a mime-type check to the process of uploading an attachment
to the wiki, and will disallow files outside of a specific whitelist
of permitted types.

The whitelist is specified through constance, with a simple default of
just the common image formats, but as a constance key it'll be
editable through the admin without needing to tweak code.

https://github.com/mozilla/kuma/commit/cdff28dc2fa71a3d5280c84777ef7ce18ab4bbfe
Merge pull request #638 from ubernostrum/file-type-filter

Fix bug 792955: Build file upload filter