diff options
| author | Marios Pomonis <pomonis@google.com> | 2019-12-11 12:47:52 -0800 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2020-05-22 21:19:38 +0100 |
| commit | f29a947a928e9464e177c97bb7b4bea0f4f0f765 (patch) | |
| tree | e3098c8ec0505ab9d2634220fddb419faec550d4 | |
| parent | 37d1c23edefc176c5b54fb5447f94ae2b5c06105 (diff) | |
| download | linux-stable-f29a947a928e9464e177c97bb7b4bea0f4f0f765.tar.gz | |
KVM: x86: Protect DR-based index computations from Spectre-v1/L1TF attacks
commit ea740059ecb37807ba47b84b33d1447435a8d868 upstream.
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>
Reviewed-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -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 8bee2faf04dc19..730b3beeda6ae8 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -801,9 +801,11 @@ static void kvm_update_dr7(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; @@ -848,9 +850,11 @@ EXPORT_SYMBOL_GPL(kvm_set_dr); static 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: if (kvm_read_cr4_bits(vcpu, X86_CR4_DE)) |