On Mon, Feb 26, 2024 at 02:03:31PM -0500, Paolo Bonzini wrote:
> There is no danger to the kernel if userspace provides a 64-bit value that
> has the high bits set, but for whatever reason happ[ens to resolve to an
^
remove the messy char.
> address that has something mapped there. KVM uses the checked version
> of put_user() in kvm_x86_dev_get_attr().
See from the code change, not just kvm_x86_dev_get_attr().
Thanks,
Yilun
>
> Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> arch/x86/kvm/x86.c | 24 +++---------------------
> 1 file changed, 3 insertions(+), 21 deletions(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index f3f7405e0628..14c969782d73 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4791,25 +4791,13 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
> return r;
> }
>
> -static inline void __user *kvm_get_attr_addr(struct kvm_device_attr *attr)
> -{
> - void __user *uaddr = (void __user*)(unsigned long)attr->addr;
> -
> - if ((u64)(unsigned long)uaddr != attr->addr)
> - return ERR_PTR_USR(-EFAULT);
> - return uaddr;
> -}
> -
> static int kvm_x86_dev_get_attr(struct kvm_device_attr *attr)
> {
> - u64 __user *uaddr = kvm_get_attr_addr(attr);
> + u64 __user *uaddr = u64_to_user_ptr(attr->addr);
>
> if (attr->group)
> return -ENXIO;
>
> - if (IS_ERR(uaddr))
> - return PTR_ERR(uaddr);
> -
> switch (attr->attr) {
> case KVM_X86_XCOMP_GUEST_SUPP:
> if (put_user(kvm_caps.supported_xcr0, uaddr))
> @@ -5664,12 +5652,9 @@ static int kvm_arch_tsc_has_attr(struct kvm_vcpu *vcpu,
> static int kvm_arch_tsc_get_attr(struct kvm_vcpu *vcpu,
> struct kvm_device_attr *attr)
> {
> - u64 __user *uaddr = kvm_get_attr_addr(attr);
> + u64 __user *uaddr = u64_to_user_ptr(attr->addr);
> int r;
>
> - if (IS_ERR(uaddr))
> - return PTR_ERR(uaddr);
> -
> switch (attr->attr) {
> case KVM_VCPU_TSC_OFFSET:
> r = -EFAULT;
> @@ -5687,13 +5672,10 @@ static int kvm_arch_tsc_get_attr(struct kvm_vcpu *vcpu,
> static int kvm_arch_tsc_set_attr(struct kvm_vcpu *vcpu,
> struct kvm_device_attr *attr)
> {
> - u64 __user *uaddr = kvm_get_attr_addr(attr);
> + u64 __user *uaddr = u64_to_user_ptr(attr->addr);
> struct kvm *kvm = vcpu->kvm;
> int r;
>
> - if (IS_ERR(uaddr))
> - return PTR_ERR(uaddr);
> -
> switch (attr->attr) {
> case KVM_VCPU_TSC_OFFSET: {
> u64 offset, tsc, ns;
> --
> 2.39.1
>
>
>
