Andi Kleen wrote: > On Tuesday 22 August 2006 16:25, Adrian Bunk wrote: > >> On Tue, Aug 22, 2006 at 03:50:57PM +0200, Andi Kleen wrote: >> >>>> this would need a "const after boot" section; which is really not hard >>>> to make and probably useful for a lot more things.... todo++ >>>> >>> except for anything that needs tlb entries in user space. And it only gives you >>> false sense of security. --todo >>> >> What's the alternative? >> > > The alternative is to not protect it, since protecting it doesn't > offer any significant additional security over not protecting it. > Didn't someone point out yet that if you are vulnerable to someone loading a kernel module of their choosing, you lose, plain and simple? You don't need paravirt-ops to implement a rootkit, and it doesn't make it any easier, and write protecting it is totally useless. How do you think VMware runs on Linux? It takes over the hardware entirely, loads a hypervisor, and starts running in a completely different world. And it doesn't even need to use a single _GPL'd export to do that. Write protection is great as a debug option to find accidental memory corruptions. It is useless as a technique to prevent subversion. Um hello, you're already at CPL-0. Just rewrite the page tables already. >> Change it from a struct to a compile time choice? >> > > One of the design goals of paravirt-ops was to allow single binaries > that run on both native hardware and on hypervisors. So that would > be a non starter. Strongly agree. Zach
