Fix path traversal in document upload (arbitrary file write) - #388
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Hi @overskye , thank you for the vulnerability fix! |
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Hi, I have a small edit :)
When uploading a document, the filename from the form was joined straight into the library path with filepath.Join, which doesn't strip .. segments. So a filename like ../../etc/cron.d/evil.epub would end up written outside the library folder entirely. Upload requires the admin role, but that's meant for managing the library, not the whole server, so this let an admin account overwrite arbitrary files anywhere the app process can write, cron jobs, systemd units, static files, whatever's writable.
Fixed by running the filename through filepath.Base before building the path, so only the bare name is used and nothing can escape the library directory. Added a test that uploads a file named with a traversal path and checks it lands inside the library folder and nothing gets written outside it, confirmed it fails on the old code and passes now.