diff options
author | Marios Pomonis <pomonis@google.com> | 2019-12-11 12:47:46 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-14 16:30:00 -0500 |
commit | 7cbb0333aed407c32be635bcd5802caa538466a5 (patch) | |
tree | f81d8ad71243fe35bdb55ba96036302c3223e7be /arch | |
parent | c3ccf2fdfc89871042659ae1463fd1d9665fdfef (diff) |
KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF attacks
[ Upstream commit 4bf79cb089f6b1c6c632492c0271054ce52ad766 ]
This fixes a Spectre-v1/L1TF vulnerability in kvm_lapic_reg_write().
This function contains index computations based on the
(attacker-controlled) MSR number.
Fixes: 0105d1a52640 ("KVM: x2apic interface to lapic")
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: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/x86/kvm/lapic.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index 3c70f6c76d3a..ce8c4ae25c15 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -36,6 +36,7 @@ #include <asm/delay.h> #include <linux/atomic.h> #include <linux/jump_label.h> +#include <linux/nospec.h> #include "kvm_cache_regs.h" #include "irq.h" #include "trace.h" @@ -1432,15 +1433,21 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val) case APIC_LVTTHMR: case APIC_LVTPC: case APIC_LVT1: - case APIC_LVTERR: + case APIC_LVTERR: { /* TODO: Check vector */ + size_t size; + u32 index; + if (!kvm_apic_sw_enabled(apic)) val |= APIC_LVT_MASKED; - val &= apic_lvt_mask[(reg - APIC_LVTT) >> 4]; + size = ARRAY_SIZE(apic_lvt_mask); + index = array_index_nospec( + (reg - APIC_LVTT) >> 4, size); + val &= apic_lvt_mask[index]; apic_set_reg(apic, reg, val); - break; + } case APIC_LVTT: if (!kvm_apic_sw_enabled(apic)) |