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| author | Marios Pomonis <pomonis@google.com> | 2019-12-11 23:47:47 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-15 00:31:04 +0300 |
| commit | 53caab16f6305f0773545bec25faa749d1a06f90 (patch) | |
| tree | 973d02d2e9a2ee64bde2a88cec8caa8f802916f3 /arch | |
| parent | 113857794697b60391ffc4de71c50ac67233928c (diff) | |
| download | linux-53caab16f6305f0773545bec25faa749d1a06f90.tar.xz | |
KVM: x86: Protect MSR-based index computations in fixed_msr_to_seg_unit() from Spectre-v1/L1TF attacks
commit 25a5edea71b7c154b6a0b8cec14c711cafa31d26 upstream.
This fixes a Spectre-v1/L1TF vulnerability in fixed_msr_to_seg_unit().
This function contains index computations based on the
(attacker-controlled) MSR number.
Fixes: de9aef5e1ad6 ("KVM: MTRR: introduce fixed_mtrr_segment table")
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/mtrr.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c index 0149ac59c273..3e3016411020 100644 --- a/arch/x86/kvm/mtrr.c +++ b/arch/x86/kvm/mtrr.c @@ -17,6 +17,7 @@ */ #include <linux/kvm_host.h> +#include <linux/nospec.h> #include <asm/mtrr.h> #include "cpuid.h" @@ -202,11 +203,15 @@ static bool fixed_msr_to_seg_unit(u32 msr, int *seg, int *unit) break; case MSR_MTRRfix16K_80000 ... MSR_MTRRfix16K_A0000: *seg = 1; - *unit = msr - MSR_MTRRfix16K_80000; + *unit = array_index_nospec( + msr - MSR_MTRRfix16K_80000, + MSR_MTRRfix16K_A0000 - MSR_MTRRfix16K_80000 + 1); break; case MSR_MTRRfix4K_C0000 ... MSR_MTRRfix4K_F8000: *seg = 2; - *unit = msr - MSR_MTRRfix4K_C0000; + *unit = array_index_nospec( + msr - MSR_MTRRfix4K_C0000, + MSR_MTRRfix4K_F8000 - MSR_MTRRfix4K_C0000 + 1); break; default: return false; |