On 28/02/2016 16:35, Michael S. Tsirkin wrote:
> Calling return copy_to_user(...) or return copy_from_user in an ioctl
> will not do the right thing if there's a pagefault:
> copy_to_user/copy_from_user return the number of bytes not copied in
> this case.
>
> Fix up kvm on mips to do
> return copy_to_user(...)) ? -EFAULT : 0;
> and
> return copy_from_user(...)) ? -EFAULT : 0;
>
> everywhere.
>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
> ---
>
> Untested.
>
> arch/mips/kvm/mips.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/mips/kvm/mips.c b/arch/mips/kvm/mips.c
> index 8bc3977..3110447 100644
> --- a/arch/mips/kvm/mips.c
> +++ b/arch/mips/kvm/mips.c
> @@ -702,7 +702,7 @@ static int kvm_mips_get_reg(struct kvm_vcpu *vcpu,
> } else if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U128) {
> void __user *uaddr = (void __user *)(long)reg->addr;
>
> - return copy_to_user(uaddr, vs, 16);
> + return copy_to_user(uaddr, vs, 16) ? -EFAULT : 0;
> } else {
> return -EINVAL;
> }
> @@ -732,7 +732,7 @@ static int kvm_mips_set_reg(struct kvm_vcpu *vcpu,
> } else if ((reg->id & KVM_REG_SIZE_MASK) == KVM_REG_SIZE_U128) {
> void __user *uaddr = (void __user *)(long)reg->addr;
>
> - return copy_from_user(vs, uaddr, 16);
> + return copy_from_user(vs, uaddr, 16) ? -EFAULT : 0;
> } else {
> return -EINVAL;
> }
>
Applied with the commit message tweak suggested by Sergei.
Paolo
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