From mboxrd@z Thu Jan 1 00:00:00 1970 From: tytso@mit.edu (Theodore Ts'o) Date: Wed, 29 Nov 2017 01:36:39 -0500 Subject: [kernel-hardening] Re: [PATCH v5 next 5/5] net: modules: use request_module_cap() to load 'netdev-%s' modules In-Reply-To: References: <20171128193243.4fymnjk7fplqw62x@thunk.org> <20171128232320.22zo324g5wvo2lce@thunk.org> <20171128234920.awfwicihuudw5ogx@thunk.org> Message-ID: <20171129063639.tuacfa2op6fgj6he@thunk.org> To: linux-security-module@vger.kernel.org List-Id: linux-security-module.vger.kernel.org On Tue, Nov 28, 2017 at 04:18:59PM -0800, Kees Cook wrote: > There's also a difference between immutable CONFIG options that cannot > be disabled at runtime, those that can, global sysctls, per-namespace > controls, etc etc. The kernel is all about providing admins with knobs > to tweak their performance and security. Suddenly being told that we > can't create optional improvements is very odd. I just think that tweakable knobs are mostly pointless. From my experience the number of sysadmins that adjust knobs is ***tiny***[1]. Put another way, the effort to determine whether tweaking a knob will result in breakages or will be safe is as much work as creating a white list of modules that are allowed to be loaded. [1] And I say that having providing a lot of knobs for ext4. :-) This is why some on the kernel-hardening list have argued for making the default to be opt-out, which means some users will be breaken (and their answer to that seems to be, "oh well --- gotta break some eggs to make an omlette". Sucks if you're one of the eggs, though.) And I don't see how systemd magically means no one will be broken. If you have a non-root process trying to invoke a line discpline which has to be loaded as a module, if you flip the switch, that process will be broken. How does using systemd make the problem go away? - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-security-module" in the body of a message to majordomo at vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html