Guard tar/zip extraction against path-traversal (CVE-2007-4559)#2458
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Guard tar/zip extraction against path-traversal (CVE-2007-4559)#2458dsblank wants to merge 2 commits into
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Gramps package (.gpkg) import extracted archive members with TarFile.extract() without checking their paths. A crafted .gpkg file could use an absolute path, a "../" path-traversal name, or a symlink/hardlink to create or overwrite files outside the intended media directory. Each archive member's resolved path is now validated before extraction, and extraction is aborted if any member would escape the target directory. Fixes #12911.
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@DavidMStraub |
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.gpkg is disallowed in Gramps Web API precisely because it's not safe. There was a path traversal vulnerability in the media importer though, see GHSA-m5gr-86j6-99jp and gramps-project/gramps-web-api@3ed4342. |
The addon/plugin installer (load_addon_file() in gramps/gen/plug/utils.py) downloads or opens a .zip or .tar.gz addon package and extracts it into the user's plugin directory. Neither the custom Zipfile.extractall() wrapper nor the tarfile.TarFile.extractall() call validated member paths, so a crafted or MITM'd addon package could use an absolute path, a "../" path-traversal name, or a symlink/hardlink to create or overwrite files outside the intended plugin directory (the same class of bug as CVE-2007-4559, aka "Zip Slip"). The path-traversal checks added for the .gpkg importer in the previous commit have been factored out into a shared gramps.gen.utils.safearchive module and are now also applied here before any zip or tar member is extracted. Fixes #12911.
dsblank
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Thank you @emyoulation for mentioning zip importer (in general). I have updated the PR to fix all known security issues in gramps zip/tar importing. |
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Summary
.gpkgimporter (gramps/plugins/importer/importgpkg.py) extracted archive members withtarfile.TarFile.extract()without validating their paths, vulnerable to CVE-2007-4559 / "Zip Slip" (see also python/cpython#73974).load_addon_file()ingramps/gen/plug/utils.py) has the same class of bug in two places: the customZipfile.extractall()wrapper (used for.zipaddon packages) and a baretarfile.TarFile.extractall()call (used for.tar.gz/.tgzaddon packages). This is arguably higher risk than the.gpkgcase since addon packages are fetched from a URL (the Gramps addon server or a configured mirror) rather than a file the user deliberately imports.../path-traversal member name, or a symlink/hardlink to create or overwrite files outside the intended target directory (media directory for.gpkg, plugin directory for addons).gramps/gen/utils/safearchive.pymodule (is_safe_archive_member(),is_safe_tar_member()) and applied it at all three extraction sites before any member is written to disk. This is a self-contained workaround that does not rely on Python 3.12+'sfilter=extraction parameter (PEP 706), so it works across all Python versions Gramps supports (3.10+).Fixes #12911.
Test plan
gramps/gen/utils/test/safearchive_test.py— unit tests for the shared helpers (absolute paths,../traversal, symlink/hardlink escapes).gramps/plugins/importer/test/importgpkg_test.py— integration-style test against a crafted malicious tar archive.Zipfile.extractall()(raisesValueError) and via the addon-installer's tar-member pre-check; a benign zip with a real directory entry still extracts correctly (no regression).python3 -m unittest gramps.gen.utils.test.safearchive_test gramps.plugins.importer.test.importgpkg_test -v— all pass.black --checkon all changed files.mypy(full project) — no issues.🤖 Generated with Claude Code