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.
If someone wants a shell command wrapper, they can load a contrib that delegates the hook to a shell command. So we can just ship a contrib, which acts both as test coverage for the feature, and a shell-command-support wrapper for anyone who desires that.
