| From 14e32321f3606e4b0970200b6e5e47ee6f1e6410 Mon Sep 17 00:00:00 2001 |
| From: Marios Pomonis <pomonis@google.com> |
| Date: Wed, 11 Dec 2019 12:47:43 -0800 |
| Subject: KVM: x86: Refactor picdev_write() to prevent Spectre-v1/L1TF attacks |
| |
| From: Marios Pomonis <pomonis@google.com> |
| |
| commit 14e32321f3606e4b0970200b6e5e47ee6f1e6410 upstream. |
| |
| This fixes a Spectre-v1/L1TF vulnerability in picdev_write(). |
| It replaces index computations based on the (attacked-controlled) port |
| number with constants through a minor refactoring. |
| |
| Fixes: 85f455f7ddbe ("KVM: Add support for in-kernel PIC emulation") |
| |
| Signed-off-by: Nick Finco <nifi@google.com> |
| Signed-off-by: Marios Pomonis <pomonis@google.com> |
| Reviewed-by: Andrew Honig <ahonig@google.com> |
| Cc: stable@vger.kernel.org |
| Reviewed-by: Jim Mattson <jmattson@google.com> |
| Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| arch/x86/kvm/i8259.c | 6 +++++- |
| 1 file changed, 5 insertions(+), 1 deletion(-) |
| |
| --- a/arch/x86/kvm/i8259.c |
| +++ b/arch/x86/kvm/i8259.c |
| @@ -460,10 +460,14 @@ static int picdev_write(struct kvm_pic * |
| switch (addr) { |
| case 0x20: |
| case 0x21: |
| + pic_lock(s); |
| + pic_ioport_write(&s->pics[0], addr, data); |
| + pic_unlock(s); |
| + break; |
| case 0xa0: |
| case 0xa1: |
| pic_lock(s); |
| - pic_ioport_write(&s->pics[addr >> 7], addr, data); |
| + pic_ioport_write(&s->pics[1], addr, data); |
| pic_unlock(s); |
| break; |
| case 0x4d0: |
