Patch-mainline: v5.19-rc8

Git-commit: cf5029d5dd7cb0aaa53250fa9e389abd231606b3

References: git-fixes

From: Aaron Lewis <aaronlewis@google.com>

Date: Thu, 14 Jul 2022 16:13:15 +0000

Subject: [PATCH] KVM: x86: Protect the unused bits in MSR exiting flags

The flags for KVM_CAP_X86_USER_SPACE_MSR and KVM_X86_SET_MSR_FILTER

have no protection for their unused bits.  Without protection, future

development for these features will be difficult.  Add the protection

needed to make it possible to extend these features in the future.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>

Message-Id: <20220714161314.1715227-1-aaronlewis@google.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Signed-off-by: Juergen Gross <jgross@suse.com>

---

 arch/x86/kvm/x86.c | 8 ++++++++

 1 file changed, 8 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c

index 143e37298d8a..e5fa335a4ea7 100644

--- a/arch/x86/kvm/x86.c

+++ b/arch/x86/kvm/x86.c

@@ -6029,6 +6029,11 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm,

 		r = 0;

 		break;

 	case KVM_CAP_X86_USER_SPACE_MSR:

+		r = -EINVAL;

+		if (cap->args[0] & ~(KVM_MSR_EXIT_REASON_INVAL |

+				     KVM_MSR_EXIT_REASON_UNKNOWN |

+				     KVM_MSR_EXIT_REASON_FILTER))

+			break;

 		kvm->arch.user_space_msr_mask = cap->args[0];

 		r = 0;

 		break;

@@ -6183,6 +6188,9 @@ static int kvm_vm_ioctl_set_msr_filter(struct kvm *kvm, void __user *argp)

 	if (copy_from_user(&filter, user_msr_filter, sizeof(filter)))

 		return -EFAULT;

+	if (filter.flags & ~KVM_MSR_FILTER_DEFAULT_DENY)

+		return -EINVAL;

+

 	for (i = 0; i < ARRAY_SIZE(filter.ranges); i++)

 		empty &= !filter.ranges[i].nmsrs;

-- 

2.35.3