private keys shouldn't be world-readable

[EvilBit]

All key material, including private keys, are created world-readable (0644 here) at the moment.

Exposing this secret key material to unprivileged users and processes poses a security vulnerability.

[EvilBit]

Oh, and by the way, thanks a lot for this great tool - finally a workable secure boot management tool :)

[Foxboron]

Yolo, copy-pasted code. Thanks :)

[ericonr]

Interesting, my keys are 600... I wonder when the regression happened.

[EvilBit]

Interesting, my keys are 600... I wonder when the regression happened.

I just traversed backwards through git blame and the permissions in SaveKey were 0644 since the initial commit.

But here the initial creation of the files was removed from CreateKey (which set 0600) and relied now on the erroneous permissions in SaveKey.

[EvilBit]

Maybe the code should even check for too permissive file permissions and refuse signing in this case. Like OpenSSH enforces it for private keys.

[ericonr]

I think that's reasonable, but please with better error messages :p

[Foxboron]

We can just do an var ErrInvalidPrivKeyPerms = errors.new("...something") and match it in main.go to give something human readable error back.

https://github.com/Foxboron/sbctl/blob/master/cmd/sbctl/main.go#L69-L78

[Foxboron]

Fixed with ea325ca