On Sun, 9 Sep 2018 20:04:17 +0200 Salvatore Mesoraca <s.mesoraca16@xxxxxxxxx> wrote: > +=============================== > +Hardening Configuration Options > +=============================== > + > +This is a list of configuration options that are useful for hardening purposes. > +These options are divided in 4 levels based on the magnitude of their negative > +side effects, not on their importance or usefulness: > + > + - **Low**: Negligible performance impact. No user-space breakage. > + - **Medium**: Some performance impact and/or user-space breakage for > + few users. > + - **High**: Notable performance impact and/or user-space breakage for > + many users. > + - **Extreme**: Big performance impact and/or user-space breakage for > + most users. > + > +In other words: **Low** level contains protections that *everybody* can and > +should use; **Medium** level should be usable by *most people* without issues; > +**High** level may cause *some trouble*, especially from a *performance* > +perspective; **Extreme** level contains protections that *few people* may want > +to enable, some people will probably *cherry-pick* some options from here based > +on their needs. > + > +For further details about which option is included in each level, please read > +the description below, for more information on any particular option refer to > +their help page. > + > +The content of this list is automatically translated into *config fragments* > +that can be used to apply the suggested hardening options to your current > +configuration. > +To use them you just need to run ``make hardened$LEVELconfig`` (e.g. > +``make hardenedhighconfig``). Some overall thoughts: - As Sam asked: who are the users of this feature? Presumably you have some real people out there in mind for each of these levels, or you would not have created them? - Who will maintain it? The list of hardening-relevant configuration options is always in high flux, as our understanding of the security implications of each. This feature will require some significant ongoing attention or it will quickly become stale. I think it needs a MAINTAINERS entry. - It's a little strange to see an RST document used as the input for the kernel configuration process. Assuming this is really the best way to do this (and I worry about things like duplicated descriptions of kernel configuration options), you should, at a minimum, carefully document the format of this file at the beginning. Otherwise people will surely break it. In fact, they'll break it anyway, so more checking in the processing script seems indicated. Without having thought it through in great depth, I suspect that a better approach might be to find a way to mark the hardening level in the Kconfig entries. - You have ordered the options alphabetically, but that is, I would argue, not the best way. My guess is that people would read this file to answer the question of "just how many bullets will hardening level H put into my foot?" So I would sort them by hardening level as the primary key. Thanks, jon
