diff options
| author |   Marios Pomonis <pomonis@google.com> | 2019-12-11 12:47:52 -0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2020-01-27 19:59:43 +0100 |
| commit | ea740059ecb37807ba47b84b33d1447435a8d868 (patch) | |
| tree | 34babb46daa16bbf8d8735b8aa9d9823c01af6ec /arch/x86/kvm/x86.c | |
| parent | KVM: x86: Protect exit_reason from being used in Spectre-v1/L1TF attacks (diff) | |
| download | linux-dev-ea740059ecb37807ba47b84b33d1447435a8d868.tar.xz linux-dev-ea740059ecb37807ba47b84b33d1447435a8d868.zip | |
KVM: x86: Protect DR-based index computations from Spectre-v1/L1TF attacks
This fixes a Spectre-v1/L1TF vulnerability in __kvm_set_dr() and
kvm_get_dr().
Both kvm_get_dr() and kvm_set_dr() (a wrapper of __kvm_set_dr()) are
exported symbols so KVM should tream them conservatively from a security
perspective.
Fixes: 020df0794f57 ("KVM: move DR register access handling into generic code")
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/x86.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 913e55f6dca3..780224e76723 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -1063,9 +1063,11 @@ static u64 kvm_dr6_fixed(struct kvm_vcpu *vcpu) static int __kvm_set_dr(struct kvm_vcpu *vcpu, int dr, unsigned long val) { + size_t size = ARRAY_SIZE(vcpu->arch.db); + switch (dr) { case 0 ... 3: - vcpu->arch.db[dr] = val; + vcpu->arch.db[array_index_nospec(dr, size)] = val; if (!(vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP)) vcpu->arch.eff_db[dr] = val; break; @@ -1102,9 +1104,11 @@ EXPORT_SYMBOL_GPL(kvm_set_dr); int kvm_get_dr(struct kvm_vcpu *vcpu, int dr, unsigned long *val) { + size_t size = ARRAY_SIZE(vcpu->arch.db); + switch (dr) { case 0 ... 3: - *val = vcpu->arch.db[dr]; + *val = vcpu->arch.db[array_index_nospec(dr, size)]; break; case 4: /* fall through */ |