Re: [dm-crypt] 'discard' as default

On 3 Jan 2019 18:36 +0100, from [email protected] (Milan Broz):
> We can (and want) to support both sides, just default should be on
> the secure side.

I agree, there definitely are situations in which TRIM pass-through
coupled with FDE makes sense. (There are also situations in which
other security-reducing choices can make sense in conjunction with
FDE. That depends on the threat model.) But _reducing_ the security
should be a conscious, informed decision.

Give me secure defaults, and let me decide if I want to reduce
security in favor of other goals, including performance.

For an interactive installation (since the original question was in
the context of an OS installation), you can just ask the person
installing the system, while indicating that there may be security
disadvantages to allowing TRIM. Not really much different from how I
believe the Debian installer currently asks whether to overwrite a
LUKS backing device with random data (which has the downside of taking
a potentially significant amount of time during the installation).

-- 
Michael Kjörling • https://michael.kjorling.se • [email protected]
  “The most dangerous thought that you can have as a creative person
              is to think you know what you’re doing.” (Bret Victor)