Messages in this thread | | | Date | Fri, 7 Nov 2014 21:05:01 +0100 | From | Borislav Petkov <> | Subject | Re: [PATCH 8/8] x86, microcode, intel: defend apply_microcode_intel with BUG_ON |
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On Mon, Sep 08, 2014 at 02:37:54PM -0300, Henrique de Moraes Holschuh wrote: > Microcode updates that requires an unknown loader should never reach the > apply_* functions (the code should have rejected it earlier). Likewise > for an unknown microcode header layout. > > Signed-off-by: Henrique de Moraes Holschuh <hmh@hmh.eng.br> > --- > arch/x86/kernel/cpu/microcode/intel.c | 2 ++ > arch/x86/kernel/cpu/microcode/intel_early.c | 2 ++ > 2 files changed, 4 insertions(+) > > diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c > index 40caef1..439681f 100644 > --- a/arch/x86/kernel/cpu/microcode/intel.c > +++ b/arch/x86/kernel/cpu/microcode/intel.c > @@ -157,6 +157,8 @@ static int apply_microcode_intel(int cpu) > if (mc_intel == NULL) > return 0; > > + BUG_ON(mc_intel->hdr.hdrver != 1 || mc_intel->hdr.ldrver != 1); > + > /* Intel SDM vol 3A section 9.11.6, page 9-34 */ > if (WARN_ONCE((unsigned long)(mc_intel->bits) % 16, > "microcode data incorrectly aligned")) > diff --git a/arch/x86/kernel/cpu/microcode/intel_early.c b/arch/x86/kernel/cpu/microcode/intel_early.c > index 994c59b..095db11 100644 > --- a/arch/x86/kernel/cpu/microcode/intel_early.c > +++ b/arch/x86/kernel/cpu/microcode/intel_early.c > @@ -671,6 +671,8 @@ static int apply_microcode_early(struct mc_saved_data *mc_saved_data, > if (mc_intel == NULL) > return 0; > > + BUG_ON(mc_intel->hdr.hdrver != 1 || mc_intel->hdr.ldrver != 1); > + > mcu_data = mc_intel->bits; > aligned_mcu_data = mc_intel->bits;
Both not needed, because we're running all microcode through microcode_sanity_check() first which already does that check.
-- Regards/Gruss, Boris.
Sent from a fat crate under my desk. Formatting is fine. --
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