Comment 1 for bug 825458

This is a regression: we recently changed our url processing to only accept urls we would generate, and we forgot that we use untrusted data (filenames) in urls sent to the main appserver (because the appserver needs to check authentication cookies before deciding whether to redirect to the private librarian, for the case of private bugs). This change was made to avoid a set of systematic bugs and glitches in url routing.

one way to address this would be to change our implementation of that change, another would be to make the urls we generate, even for attachments with unicode elements or whitespace, match our more restrictive rules (e.g. by folding the name down).