fix: prevent path traversal in apkg media import#5153
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os.path.commonprefix matches characters rather than path components. Use startswith(dir + os.sep) instead to prevent path traversal.
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Thanks for the PR! To ensure we're solving the right problems, we require all PRs to be linked to an open issue. Please open one describing the problem this PR addresses so we can discuss the implementation there first. You have 4 days to link an issue before this PR is automatically closed, it can be reopened at any time after that. Looking forward to the discussion!
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Documentation build overview
25 files changed ·
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The legacy import option was removed in ankitects#3536. Remove the dead code associated with the legacy importer.
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We might want to clean up legacy_import_export() as well? It's still referenced by the browser. |
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Linked issue (required)
#5167
Motivation
The
.apkgmedia usesos.path.commonprefix, which compares characters, not path components. A media filename resolving to a sibling directory that shares the media folder's name prefix passes the check, so a malicious.apkgcan write outsidecollection.media(path traversal / arbitrary file write).A second commit removes the legacy importer entirely. The legacy import option was removed in #3536, leaving pylib/anki/importing, qt/aqt/importing.py and their dialog forms unreachable.
Steps to reproduce
.apkgwhose media maps a file into a sibling directory whose name begins with the media folder's name.collection.media. After: "Invalid file".Testing performed
Tested by importing .apkg and .csv decks via File > Import and drag-and-drop on the main branch and on the PR branch. Cards import completes without problems.