diff options
| author | Marios Pomonis <pomonis@google.com> | 2019-12-11 12:47:49 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2020-05-22 21:19:38 +0100 |
| commit | 37d1c23edefc176c5b54fb5447f94ae2b5c06105 (patch) | |
| tree | 24f3bb68e98db7e7d2ecd3dff6fb001a232a1ed3 | |
| parent | 528bb39449961c9177b540931a1e39fb6c427707 (diff) | |
| download | linux-stable-37d1c23edefc176c5b54fb5447f94ae2b5c06105.tar.gz | |
KVM: x86: Protect MSR-based index computations from Spectre-v1/L1TF attacks in x86.c
commit 6ec4c5eee1750d5d17951c4e1960d953376a0dda upstream.
This fixes a Spectre-v1/L1TF vulnerability in set_msr_mce() and
get_msr_mce().
Both functions contain index computations based on the
(attacker-controlled) MSR number.
Fixes: 890ca9aefa78 ("KVM: Add MCE support")
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>]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | arch/x86/kvm/x86.c | 11 |
1 files changed, 9 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index b0d5da6cc93656..8bee2faf04dc19 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -48,6 +48,7 @@ #include <linux/pci.h> #include <linux/timekeeper_internal.h> #include <linux/pvclock_gtod.h> +#include <linux/nospec.h> #include <trace/events/kvm.h> #define CREATE_TRACE_POINTS @@ -1916,7 +1917,10 @@ static int set_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 data) default: if (msr >= MSR_IA32_MC0_CTL && msr < MSR_IA32_MCx_CTL(bank_num)) { - u32 offset = msr - MSR_IA32_MC0_CTL; + u32 offset = array_index_nospec( + msr - MSR_IA32_MC0_CTL, + MSR_IA32_MCx_CTL(bank_num) - MSR_IA32_MC0_CTL); + /* only 0 or all 1s can be written to IA32_MCi_CTL * some Linux kernels though clear bit 10 in bank 4 to * workaround a BIOS/GART TBL issue on AMD K8s, ignore @@ -2443,7 +2447,10 @@ static int get_msr_mce(struct kvm_vcpu *vcpu, u32 msr, u64 *pdata) default: if (msr >= MSR_IA32_MC0_CTL && msr < MSR_IA32_MCx_CTL(bank_num)) { - u32 offset = msr - MSR_IA32_MC0_CTL; + u32 offset = array_index_nospec( + msr - MSR_IA32_MC0_CTL, + MSR_IA32_MCx_CTL(bank_num) - MSR_IA32_MC0_CTL); + data = vcpu->arch.mce_banks[offset]; break; } |