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| author |   Marios Pomonis <pomonis@google.com> | 2019-12-11 12:47:47 -0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2020-01-27 19:59:39 +0100 |
| commit | 25a5edea71b7c154b6a0b8cec14c711cafa31d26 (patch) | |
| tree | 202e992a8d119b2f56e4db179ccafaed2e14621a /arch/x86/kvm/mtrr.c | |
| parent | KVM: x86: Protect kvm_lapic_reg_write() from Spectre-v1/L1TF attacks (diff) | |
| download | linux-dev-25a5edea71b7c154b6a0b8cec14c711cafa31d26.tar.xz linux-dev-25a5edea71b7c154b6a0b8cec14c711cafa31d26.zip | |
KVM: x86: Protect MSR-based index computations in fixed_msr_to_seg_unit() from Spectre-v1/L1TF attacks
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>
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/mtrr.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/kvm/mtrr.c b/arch/x86/kvm/mtrr.c index 25ce3edd1872..7f0059aa30e1 100644 --- a/arch/x86/kvm/mtrr.c +++ b/arch/x86/kvm/mtrr.c @@ -192,11 +192,15 @@ 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; |