mirror of
https://github.com/hedgedoc/hedgedoc.git
synced 2024-12-23 18:21:40 +00:00
9af0d85879
As this is documented in dev/getting-started.md Signed-off-by: Falk Rehse <neuringe1234@gmail.com>
60 lines
3.3 KiB
Markdown
60 lines
3.3 KiB
Markdown
# 2.0 Development Notes
|
|
This document collects notes and decisions taken during the development of HedgeDoc 2.0.
|
|
It should be converted to a properly structured documentation, but having unstructured docs
|
|
is better than having no docs.
|
|
|
|
## Supported databases
|
|
We intend to officially support and test these databases:
|
|
- SQLite (for development and smaller instances)
|
|
- PostgreSQL
|
|
- MariaDB
|
|
|
|
## Special Groups
|
|
The software provides two special groups which have no explicit users:
|
|
- `everyone` (Describing that everyone who wants to access a note can do if it is enabled in the config.)
|
|
- `loggedIn` (Describing all users which are logged in)
|
|
|
|
## Deleting notes and revisions
|
|
- The owner of a note may delete it.
|
|
- By default, this also removes all revisions and all files that were uploaded to that note.
|
|
- The owner may choose to skip deleting associated uploads, leaving them without a note.
|
|
- The frontend should show a list of all uploads that will be affected
|
|
and provide a method of skipping deletion.
|
|
- The owner of a note may delete all revisions. This effectively purges the edit
|
|
history of a note.
|
|
|
|
## Entity `create` methods
|
|
|
|
Because we need to have empty constructors in our entity classes for TypeORM to work, the actual constructor is a separate `create` method. These methods should adhere to these guidelines:
|
|
|
|
- Only require the non-optional properties of the corresponding entity
|
|
- Have no optional parameters
|
|
- Have no lists which can be empty (so probably most of them)
|
|
- Should either return a complete and fully useable instance or return a Pick/Omit type.
|
|
- Exceptions to these rules are allowed, if they are mentioned in the method documentation
|
|
|
|
## Auth tokens for the public API
|
|
The public API uses bearer tokens for authentication.
|
|
|
|
When a new token is requested via the private API, the backend generates a 64 bytes-long secret of
|
|
cryptographically secure data and returns it as a base64url-encoded string, along with an identifier.
|
|
That string can then be used by clients as a bearer token.
|
|
|
|
A SHA-512 hash of the secret is stored in the database. To validate tokens, the backend computes the hash of the provided
|
|
secret and checks it against the stored hash for the provided identifier.
|
|
|
|
### Choosing a hash function
|
|
Unfortunately, there does not seem to be any explicit documentation about our exact use-case.
|
|
Most docs describe classic password-saving scenarios and recommend bcrypt, scrypt or argon2.
|
|
These hashing functions are slow to stop brute-force or dictionary attacks, which would expose the original,
|
|
user-provided password, that may have been reused across multiple services.
|
|
|
|
We have a very different scenario:
|
|
Our API tokens are 64 bytes of cryptographically strong pseudorandom data.
|
|
Brute-force or dictionary attacks are therefore virtually impossible, and tokens are not reused across multiple services.
|
|
We therefore need to only guard against one scenario:
|
|
An attacker gains read-only access to the database. Saving only hashes in the database prevents the attacker
|
|
from authenticating themselves as a user. The hash-function does not need to be very slow,
|
|
as the randomness of the original token prevents inverting the hash. The function actually needs to be reasonably fast,
|
|
as the hash must be computed on every request to the public API.
|
|
SHA-512 (or alternatively SHA3) fits this use-case.
|