Re: ssl passphrase callback

On 11/14/19 11:07 AM, Bruce Momjian wrote:
> On Thu, Nov 14, 2019 at 11:42:05AM +0100, Magnus Hagander wrote:
>> On Wed, Nov 13, 2019 at 9:23 PM Tomas Vondra <tomas.vondra@2ndquadrant.com>
>>     I think it would be beneficial to explain why shared object is more
>>     secure than an OS command. Perhaps it's common knowledge, but it's not
>>     quite obvious to me.
>>
>>
>> Yeah, that probably wouldn't hurt. It's also securely passing from more than
>> one perspective -- both from the "cannot be eavesdropped" (like putting the
>> password on the commandline for example) and the requirement for escaping.
> I think a bigger issue is that if you want to give people the option of
> using a shell command or a shared object, and if you use two commands to
> control it, it isn't clear what happens if both are defined.  By using
> some character prefix to control if a shared object is used, you can use
> a single variable and there is no confusion over having two variables
> and their conflicting behavior.
>


I'm  not sure how that would work in the present instance. The shared
preloaded module installs a function and defines the params it wants. If
we somehow unify the params with ssl_passphrase_command that could look
icky, and the module would have to parse the settings string. That's not
a problem for the sample module which only needs one param, but it will
be for other more complex implementations.

I'm quite open to suggestions, but I want things to be tolerably clean.