Add platform-specific tag to rules

[r0binak]

This is only necessary for use in certain environments.

[tstromberg]

Spoke to @r0binak via e-mail, the gist here is to provide a way for folks who are only interested in rules that impact a single platform to filter by or ignore other platforms. For example, for a Linux CI/CD platform, you probably don't care about Windows hits.

What I propose is adding GOOS-style tags to our rules that only impact a subset of platforms:

• linux
• darwin
• windows
• solaris
• ...

For 3rd party rules, we'll need to apply some heuristics to auto-tag rules: for example, rules that contain Win32 in their name should be tagged as Windows.

[tstromberg]

This has launched for a fair number of 1st party rules - we still need to add code to automatically do this for 3rd party rules based on heuristics (rule name, description)

[r0binak]

@tstromberg Please tell me when this is planned to be completed in full?

[r0binak]

@egibs did you see that?

[egibs]

@r0binak just now catching up on old Issues. We've added file types to most first-party rules, but not necessarily the corresponding platforms.

In addition, modifying third-party rules is tough since any changes we make will be overwritten by our update automation.

I'll take an action item to review the first-party rules, though.

[r0binak]

@egibs how can i check this?

[egibs]

Here's a search of the rules directory showing which rules have the filetypes metadata we use to limit which rules apply to a given file:
https://github.com/search?q=repo%3Achainguard-dev%2Fmalcontent+path%3Arules+%2Ffiletypes%5Cs%2B%3D.*%2F&type=code

As far as platform coverage is concerned:
https://github.com/search?q=repo%3Achainguard-dev%2Fmalcontent+path%3Arules+%2Frule+%5Cw%2B%3A+.*%28linux%7Cmacos%7Cwindows%7Cdarwin%7Csolaris%29.*%2F&type=code