This is a note to let you know that I've just added the patch titled
KVM: x86: Protect the unused bits in MSR exiting flags
to the 5.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kvm-x86-protect-the-unused-bits-in-msr-exiting-flags.patch
and it can be found in the queue-5.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c54ed785f358b2ffd11033e61595168dc667f3da
Author: Aaron Lewis <aaronlewis@xxxxxxxxxx>
Date: Thu Jul 14 16:13:15 2022 +0000
KVM: x86: Protect the unused bits in MSR exiting flags
[ Upstream commit cf5029d5dd7cb0aaa53250fa9e389abd231606b3 ]
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@xxxxxxxxxx>
Message-Id: <20220714161314.1715227-1-aaronlewis@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Stable-dep-of: 2e3272bc1790 ("KVM: x86: Copy filter arg outside kvm_vm_ioctl_set_msr_filter()")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index e07607eed35c..ed8efd402d05 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5360,6 +5360,11 @@ 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;
@@ -5454,6 +5459,9 @@ 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;
