Re: Have an encrypted pgpass file

On 24 July 2018 at 05:53, Jeff Janes <jeff.janes@gmail.com> wrote:

On Wed, Jul 18, 2018 at 5:52 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:

Thomas Munro <thomas.munro@enterprisedb.com> writes:
> On Thu, Jul 19, 2018 at 5:46 AM, Marco van Eck <marco.vaneck@gmail.com> wrote:
>> Since .pgpass files contain plain-text passwords, I searched for an
>> alternative.
>> In the attached patch I've added the possibility to run a command to produce
>> the content of the pgpass file, in exactly the same format.

> ... Here you side step those questions completely and make that the end
> user's problem.   I like it.

... but doesn't this just encourage people to build hacks that aren't
really any more secure than the unreadable-file approach?  In fact,
I'm afraid this would be an attractive nuisance, in that people would
build one-off hacks that get no security vetting and don't really work.

I'd like to see a concrete example of a use-case that really does add
security; preferably one short and useful enough to put into the docs
so that people might copy-and-paste it rather than rolling their own.
It seems possible that something of the sort could be built atop
ssh-agent or gpg-agent, for instance.

If the goal is not unattended operation but just unannoying operation, I think the first example he provided is already that use-case.  If you already have gpg configured to use gpg-agent, then it just works.  You get encryption-at-rest, and you don't have to type in your password repeatedly in the same continuous shell session.

... and the attacker steals the key from gpg-agent.

Grabbing it from a process's memory is a bit harder than grabbing contents of a file, but not much harder. If the agent is remote then that's harder, but you can just ask the script to decrypt the pgpass for you, so again, not much of a win.

Even with a hardware crypto offload device the advantage here seems to be mainly limited to making it harder to capture data from backups or file-lifting attacks. Anything that can execute code or commands on the host can still get the credentials.