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| author | Marios Pomonis <pomonis@google.com> | 2019-12-11 12:47:46 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2020-05-22 21:19:37 +0100 |
| commit | 64c977f360f25b60c25fce462d8634386935e796 (patch) | |
| tree | d5a1070080a405336cd7c2b4cd662a32ba314087 | |
| parent | 56b51e25ffb93ae142652400c35ea43f0899d0c2 (diff) | |
| download | linux-stable-64c977f360f25b60c25fce462d8634386935e796.tar.gz | |
KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF attacks
commit 4bf79cb089f6b1c6c632492c0271054ce52ad766 upstream.
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>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.16:
- Add #include <linux/nospec.h>
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | arch/x86/kvm/lapic.c | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index d03a88cb31299..e38d6a7dfbd60 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -35,6 +35,7 @@ #include <asm/apicdef.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" @@ -1196,15 +1197,20 @@ 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_get_reg(apic, APIC_LVTT) & |