Messages in this thread | | | From | Kees Cook <> | Date | Tue, 16 Aug 2016 12:49:52 -0700 | Subject | Re: [tip:x86/boot] x86/mm: Enable KASLR for physical mapping memory regions |
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On Tue, Aug 16, 2016 at 10:50 AM, Borislav Petkov <bp@alien8.de> wrote: > On Tue, Aug 16, 2016 at 05:54:12PM +0200, Borislav Petkov wrote: >> Ok, I ran this in a guest and it finds the microcode patches properly. > > Here's a better version to take care of the APs too: > > --- > diff --git a/arch/x86/kernel/cpu/microcode/amd.c b/arch/x86/kernel/cpu/microcode/amd.c > index 27a0228c9cae..05242322e324 100644 > --- a/arch/x86/kernel/cpu/microcode/amd.c > +++ b/arch/x86/kernel/cpu/microcode/amd.c > @@ -355,6 +355,7 @@ void load_ucode_amd_ap(void) > unsigned int cpu = smp_processor_id(); > struct equiv_cpu_entry *eq; > struct microcode_amd *mc; > + u8 *cont; > u32 rev, eax; > u16 eq_id; > > @@ -371,8 +372,12 @@ void load_ucode_amd_ap(void) > if (check_current_patch_level(&rev, false)) > return; > > +#ifdef CONFIG_RANDOMIZE_MEMORY > + cont = container + PAGE_OFFSET - __PAGE_OFFSET_BASE; > +#endif > + > eax = cpuid_eax(0x00000001); > - eq = (struct equiv_cpu_entry *)(container + CONTAINER_HDR_SZ); > + eq = (struct equiv_cpu_entry *)(cont + CONTAINER_HDR_SZ);
Am I misreading this? Shouldn't it be:
cont = container; #ifdef CONFIG_RANDOMIZE_MEMORY cont += PAGE_OFFSET - __PAGE_OFFSET_BASE; #endif
(otherwise cont is undefined in the RANDOMIZE_MEMORY=n case?)
> > eq_id = find_equiv_id(eq, eax); > if (!eq_id) > @@ -434,6 +439,10 @@ int __init save_microcode_in_initrd_amd(void) > else > container = cont_va; > > +#ifdef CONFIG_RANDOMIZE_MEMORY > + container += PAGE_OFFSET - __PAGE_OFFSET_BASE; > +#endif > + > eax = cpuid_eax(0x00000001); > eax = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff); > > > -- > Regards/Gruss, > Boris. > > ECO tip #101: Trim your mails when you reply. > --
-Kees
-- Kees Cook Nexus Security
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