Messages in this thread | | | Date | Wed, 19 Dec 2007 20:14:39 +0100 | From | Radoslaw Szkodzinski (AstralStorm) <> | Subject | Re: [patch 1/2] [RFC] Simple tamper-proof device filesystem. |
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On Wed, 19 Dec 2007 21:11:11 +0900 Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> wrote:
> Hello. > > Radoslaw Szkodzinski (AstralStorm) wrote: > > Actually, who needs to create device nodes? Just prohibit everyone from > > creating them, except "installer" and "udev" personality. > > This means removing CAP_MKNOD on a global scale. > > What happens if the root tampers udev's configuration file? > The udev will create inappropriate (i.e. filename with unexpected attributes) > device nodes, won't it?
Yes. But root doesn't need access to these files, at least not usually. Create a separate user for editing config files - much lower probability of breakage. Remove almost all capabilities from root and profit.
> After all, revoking CAP_MKNOD is not enough for guaranteeing > filename and its attributes. > > This filesystem is designed to guarantee filename and its attributes, > but this filesystem has additional access control capability. > You can forbid mknod/unlink /dev/null if you want nobody to do so. > You can forbid chmod/chown /dev/null if you want nobody to do so.
You can forbid all operations on /dev (except udev) with an ACL. So, what is the need for this filesystem? [unhandled content-type:application/pgp-signature] | |