Impact
---
An attacker can read arbitrary `.md` files from the server's filesystem due to an [improper input validation](https://cwe.mitre.org/data/definitions/20.html), which results in the ability to perform a [relative path traversal](https://cwe.mitre.org/data/definitions/23.html).
CVSSv3 string: AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
PoC / Quicktest
---
To verify if you are affected, you can try to open the following URL: `http://localhost:3000/..%2F..%2FREADME#` (replace `http://localhost:3000` with your instance's base-URL e.g. `https://demo.hedgedoc.org/..%2F..%2FREADME#`).
- If you see a README page being rendered, you run an affected version.
Analysis
---
The attack works due the fact that [the internal router, passes the url-encoded alias](https://github.com/hedgedoc/hedgedoc/blob/master/lib/web/note/router.js#L26) to the `noteController.showNote`-function. This function passes the input directly to [`findNote()`](78a732abe6/lib/web/note/util.js (L10)) utility function, that will pass it on the the [`parseNoteId()`](78a732abe6/lib/models/note.js (L188-L258))-function, that tries to make sense out of the noteId/alias and check if a note already exists and if so, if a corresponding file on disk was updated.
If no note exists the [note creation-function is called](78a732abe6/lib/models/note.js (L240-L245)), which pass this unvalidated alias, with a `.md` appended, into a [`path.join()`-function](78a732abe6/lib/models/note.js (L99)) which is read from the filesystem in the follow up routine and provides the pre-filled content of the new note.
This allows an attacker to not only read arbitrary `.md` files from the filesystem, but also observes changes to them.
The usefulness of this attack can be considered limited, since mainly markdown files are use the file-ending `.md` and all markdown files contained in the hedgedoc project, like the README, are public anyway. If other protections such as a chroot or container or proper file permissions are in place, this attack's usefulness is rather limited.
Workarounds
---
On a reverse-proxy level one can force a URL-decode, which will prevent this attack because the router will not accept such a path.
For more information
---
If you have any questions or comments about this advisory:
* Open an topic on [our community forum](https://community.hedgedoc.org)
* Join our [matrix room](https://chat.hedgedoc.org)
Advisory link
---
https://github.com/hedgedoc/hedgedoc/security/advisories/GHSA-p528-555r-pf87
Signed-off-by: Christoph (Sheogorath) Kern <sheogorath@shivering-isles.com>
As explained in #391, the previous note creation logic didn't handle the case "alias is set, but it's not a file on disk". The fix introduces a separate if-statement for this scenario at the cost of a doubled filesystem read access.
Co-Authored-By: @evanlinde
Signed-off-by: Erik Michelson <github@erik.michelson.eu>
Signed-off-by: Erik Michelson <github@erik.michelson.eu>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: References in public/views
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Update links in README
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Update links in SECURITY.md
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Update links in LICENSE
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Update links in docs/configuration.md
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Update links in bin/setup
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: References in docs/guides
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: References in docs/dev
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: References in docs/guides/auth
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: References in docs/setup
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Update various links in code to the new GitHub org.
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: codiMDVersion.js is now hedgeDocVersion.js
Signed-off-by: David Mehren <git@herrmehren.de>
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: References in docs/setup/yunohost
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rebrand to HedgeDoc: Add banner and logo
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Update links in docs/guides/migrate-etherpad
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Remove note in docs/guides/auth/github
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Replace links in public/docs/features
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Add todo placeholder in docs/history
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Replace github link in public/views/index/body
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Replace github link in README
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Add logo to README
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Rename to HedgeDoc: Add note about the renaming to the front page
Signed-off-by: Tilman Vatteroth <tilman.vatteroth@tu-dortmund.de>
Removed Travis from README.md and change CodiMD to HedgeDoc in some places
Signed-off-by: Yannick Bungers <git@innay.de>
Some more renaming to HedgeDoc
- Fixed capitalization of HedgeDoc
- Added renaming for etherpad migration doc
Signed-off-by: Yannick Bungers <git@innay.de>
Changed Repo name to hedgedoc
Signed-off-by: Yannick Bungers <git@innay.de>
This does some more in depth check on the error message and minimizes
the log noise that is caused by LZString.
Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>
When we delete a user we should delete all the notes that belong to this
user including the revisions of these notes.
Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>
Right now we only flag notes as deleted. This is no longer allowed under
GDPR. Make sure you do regular backups!
Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>
As we know the length of an UUID we can check if the base64 string
of the provided UUID is long enough for a legacy base64 encoded nodeId
and stop processing it in legacy mode, if it's not the case.
This should make the ugly warning way less common.
Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>
This refactors the configs a bit to now use camel case everywhere.
This change should help to clean up the config interface and make it
better understandable.
Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>
