On Tue, Sep 16, 2014 at 10:00 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > On Tue, Sep 16, 2014 at 6:18 PM, Richard Larocque <rlarocque@xxxxxxxxxx> wrote: >> On Tue, Sep 16, 2014 at 5:27 PM, Andy Lutomirski <luto@xxxxxxxxxxxxxx> wrote: > I think that the patch should instead tweak the vvar mapping to tell > the vdso not to use rdtsc. It should be based on this: > > https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/log/?h=x86/vsyscall > > and I'll talk to hpa tomorrow about about getting that, or something > like it, into the tip tree. In particular, you'll need this: > > https://git.kernel.org/cgit/linux/kernel/git/luto/linux.git/commit/?h=x86/vsyscall&id=0cc410a05cb95e073ebfe099c9e03cef48d2be0f Crud. Now that I've said that, I realize that this won't work right if rdtscp is off. I'll drop that patch. I don't think that this changes the conclusion. It should be possible to swap out the vvar page to keep the vdso working even without rdtsc available. --Andy > > Also, this kind of inheritable restriction may end up requiring > no_new_privs or CAP_SYS_ADMIN to be secure. > > --Andy -- Andy Lutomirski AMA Capital Management, LLC -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
