#get_os_architecture doesn't always return an architecture

[smcintyre-r7]

The #get_os_architecture post API method has large holes in it's coverage. It doesn't return an architecture for non-meterpreter, non-windows sessions. That notably means any Linux shell session is unsupported.

Expected behavior

This functionality should be provided so post modules and LPEs can use it to reliably fingerprint the remote target. The returned value should be an ARCH_ constant.

Current behavior

Coverage is spotty.

[kx7m2qd]

Hi @smcintyre-r7, I'd like to work on this. My approach would be to extend get_os_architecture in post/common.rb to handle Linux/BSD shell sessions by running uname -m and mapping the output to ARCH_ constants. Would this approach work or is there a preferred method for shell command execution in post modules?

[smcintyre-r7]

@kx7m2qd That's exactly what @bwatters-r7 and I were thinking is what we need to do. We have some of the known mappings here https://github.com/rapid7/metasploit-framework/pull/21384/changes#diff-379281420ca4e5053e4d56e07fe06efa373da0115c8563c7fe5319e6909046bc but we need them consolidated and placed into an API that can be called from pretty much anywhere ideally.

Adding a class method like .uname_to_arch(uname_arch) then having get_os_architecture call it when the platform has uname is probably how I'd handle it. This is mostly a normalization problem.

[kx7m2qd]

Thanks @smcintyre-r7! I'll check the mappings in #21384 and consolidate them into a uname_to_arch class method in post/common.rb, then have get_os_architecture call it for Linux/BSD shell sessions. I'll open a PR shortly!

[smcintyre-r7]

Actually adding it as a .from_uname method to https://github.com/rapid7/rex-arch/blob/master/lib/rex/arch.rb#L14 might be best. That does mean you'd need to make multiple PRs though because of how rex-arch is a separate gem.

[kx7m2qd]

Thanks for the updated direction! I'll add .from_uname to rex-arch first, then update get_os_architecture in metasploit-framework to call it. I'll open the rex-arch PR first should I reference this issue in both PRs?

[smcintyre-r7]

I'll open the rex-arch PR first should I reference this issue in both PRs?

Yes please, referencing the issue will help us track why the changes are being made.

[kx7m2qd]

Rex-arch PR is up here: rapid7/rex-arch#13 adds Rex::Arch.from_uname with tests for all supported architectures. Will follow up with the metasploit-framework PR to wire it into get_os_architecture once this is reviewed.

@smcintyre-r7

[kx7m2qd]

@smcintyre-r7 This is the follow-up PR to rapid7/rex-arch#13 wires Rex::Arch.from_uname into get_os_architecture for Linux/BSD shell sessions. Would appreciate a review when you get a chance!