Messages in this thread | | | Date | Wed, 8 Apr 2020 17:54:53 +0200 | From | Jessica Yu <> | Subject | Re: [PATCH 4/4] x86,module: Detect CRn and DRn manipulation |
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+++ Peter Zijlstra [08/04/20 17:44 +0200]: >On Wed, Apr 08, 2020 at 09:27:26AM -0400, Steven Rostedt wrote: >> On Tue, 07 Apr 2020 13:02:40 +0200 >> Peter Zijlstra <peterz@infradead.org> wrote: > >> > + if (insn_is_mov_CRn(&insn) || insn_is_mov_DRn(&insn)) { >> > + pr_err("Module writes to CRn or DRn, please use the proper accessors: %s\n", mod->name); >> > + return -ENOEXEC; >> > + } >> > + >> >> Something like this should be done for all modules, not just out of tree >> modules. > >I'm all for it; but people were worried scanning all modules was too >expensive (I don't really believe it is, module loading just can't be a >hot-path). Also, in-tree modules are audited a lot more than out of tree >magic voodoo crap.
The intention of the original patches was to do the text scan to catch a handful of out-of-tree hypervisor modules - but now that decode_module() is being generalized to more cases, I don't mind scanning all modules.
Thanks,
Jessica
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