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Message-Id: <20200210122445.883199754@linuxfoundation.org>
Date: Mon, 10 Feb 2020 04:32:28 -0800
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Nick Finco <nifi@...gle.com>,
Marios Pomonis <pomonis@...gle.com>,
Andrew Honig <ahonig@...gle.com>,
Jim Mattson <jmattson@...gle.com>,
Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 5.5 235/367] KVM: x86: Protect ioapic_read_indirect() from Spectre-v1/L1TF attacks
From: Marios Pomonis <pomonis@...gle.com>
commit 8c86405f606ca8508b8d9280680166ca26723695 upstream.
This fixes a Spectre-v1/L1TF vulnerability in ioapic_read_indirect().
This function contains index computations based on the
(attacker-controlled) IOREGSEL register.
Fixes: a2c118bfab8b ("KVM: Fix bounds checking in ioapic indirect register reads (CVE-2013-1798)")
Signed-off-by: Nick Finco <nifi@...gle.com>
Signed-off-by: Marios Pomonis <pomonis@...gle.com>
Reviewed-by: Andrew Honig <ahonig@...gle.com>
Cc: stable@...r.kernel.org
Reviewed-by: Jim Mattson <jmattson@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
arch/x86/kvm/ioapic.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -36,6 +36,7 @@
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/export.h>
+#include <linux/nospec.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/current.h>
@@ -68,13 +69,14 @@ static unsigned long ioapic_read_indirec
default:
{
u32 redir_index = (ioapic->ioregsel - 0x10) >> 1;
- u64 redir_content;
+ u64 redir_content = ~0ULL;
- if (redir_index < IOAPIC_NUM_PINS)
- redir_content =
- ioapic->redirtbl[redir_index].bits;
- else
- redir_content = ~0ULL;
+ if (redir_index < IOAPIC_NUM_PINS) {
+ u32 index = array_index_nospec(
+ redir_index, IOAPIC_NUM_PINS);
+
+ redir_content = ioapic->redirtbl[index].bits;
+ }
result = (ioapic->ioregsel & 0x1) ?
(redir_content >> 32) & 0xffffffff :
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