From: Theodore Ts'o <ty...@mit.edu> Date: Wed, 29 Nov 2017 10:54:06 -0500
> On Wed, Nov 29, 2017 at 09:50:14AM -0500, David Miller wrote: >> From: Alan Cox <gno...@lxorguk.ukuu.org.uk> >> Date: Wed, 29 Nov 2017 13:46:12 +0000 >> >> > I really don't care what the module loading rules end up with and >> > whether we add CAP_SYS_YET_ANOTHER_MEANINGLESS_FLAG but what is >> > actually needed is to properly incorporate it into securiy ruiles >> > for whatever LSM you are using. >> >> I'm surprised we're not using the SHA1 hashes or whatever we compute >> for the modules to make sure we are loading the foo.ko that we expect >> to be. > > We do have signed modules. But this won't help us if the user is > using a distro kernel which has compiled some module which is known to > be unmaintained which everyone in the know *expects* to have 0-day > bugs, such as DCCP. That's because the DCCP module is signed. That's not what we're talking about. We're talking about making sure that loading "ppp.ko" really gets ppp.ko rather than some_other_module.ko renamed to ppp.ko via some other mechanism. Both modules have legitimate signatures so the kernel will happily load both.