This PR is a security hardning change and will break some setups.
The hardning is done to ensure the datafolder is not compromised and particularly that it is not maliciously seeded.
The changes now **requires** that the datafolder is locked down with exact permissions, or Duplicati will refuse to use it. This is a change to prior functionality where the folder would simply be locked down if it was not already locked.
Previously, a file named `insecure-permissions.txt` could be placed in the folder to instruct Duplicati not to set permissions. With this change that file is no longer supported.
The only way to opt-out of the permission check is to supply `--allow-insecure-datafolder` or the environment variable `DUPLICATI__ALLOW_INSECURE_DATAFOLDER`. Once either of those are set, Duplicati will no longer check permissions and accept folders with other permissions.
The setting can be applied to `preload.json`, but the file needs to be in a trusted location, which is either the directory with the binaries or the file pointed to by `DUPLICATI_PRELOAD_SETTINGS`. The setting cannot be placed in a `preload.json` file that is in an insecure folder as the folder is not read if the permissions are not correct.
The previous paths `/usr/local/share/Duplicati/preload.json` and `C:\ProgramData\Duplicati\preload.json` are no longer supported as they cannot be guaranteed to be locked down.
A `preload.json` in the datafolder is still supported, provided the folder passes the permission check (or the `--allow-insecure-datafolder` is passed to the executable).
For most users, this should not cause any problems as Duplicati has been locking down the folders, so they should be correctly locked down already.
The configuretool has been updated with a `secure-datafolder` command that can be used to force the correct permissions on a folder, in case the folder did not have the correct permissions.
For some Docker setups it may not be possible to set the permissions and the check will fail. These setup will need to apply `DUPLICATI__ALLOW_INSECURE_DATAFOLDER=true` in the image to run without the protections.
This PR adds support for generating a self-signed CA and then using that CA to generate TLS certificates.
A new tool `duplicati-configure` / `Duplicati.CommandLine.ConfigureTool.exe` is added to manage the certificates. The tool saves the configuration in the database and is meant to run with elevated privileges for the initial CA installation.
The option `--configure-https` can be added to server/trayicon, and if the process has permissions, this will automatically install the CA certificate.
If a CA is configured, the server will automatically issue, renew and use a TLS certificate.
With this setup, the TLS is opt-in, but once the flow is well tested, we can switch it to opt-out.
Kenneth Skovhede