On 25/03/19 19:47, David Rientjes wrote:
> This ensures that the address and length provided to DBG_DECRYPT and
> DBG_ENCRYPT do not cause an overflow.
> 
> At the same time, pass the actual number of pages pinned in memory to
> sev_unpin_memory() as a cleanup.
> 
> Reported-by: Cfir Cohen <c...@google.com>
> Signed-off-by: David Rientjes <rient...@google.com>
> ---
>  arch/x86/kvm/svm.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -6799,7 +6799,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct 
> kvm_sev_cmd *argp, bool dec)
>       struct page **src_p, **dst_p;
>       struct kvm_sev_dbg debug;
>       unsigned long n;
> -     int ret, size;
> +     unsigned int size;
> +     int ret;
>  
>       if (!sev_guest(kvm))
>               return -ENOTTY;
> @@ -6807,6 +6808,11 @@ static int sev_dbg_crypt(struct kvm *kvm, struct 
> kvm_sev_cmd *argp, bool dec)
>       if (copy_from_user(&debug, (void __user *)(uintptr_t)argp->data, 
> sizeof(debug)))
>               return -EFAULT;
>  
> +     if (!debug.len || debug.src_uaddr + debug.len < debug.src_uaddr)
> +             return -EINVAL;
> +     if (!debug.dst_uaddr)
> +             return -EINVAL;
> +
>       vaddr = debug.src_uaddr;
>       size = debug.len;
>       vaddr_end = vaddr + size;
> @@ -6857,8 +6863,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct 
> kvm_sev_cmd *argp, bool dec)
>                                                    dst_vaddr,
>                                                    len, &argp->error);
>  
> -             sev_unpin_memory(kvm, src_p, 1);
> -             sev_unpin_memory(kvm, dst_p, 1);
> +             sev_unpin_memory(kvm, src_p, n);
> +             sev_unpin_memory(kvm, dst_p, n);
>  
>               if (ret)
>                       goto err;
> 

Queued, thanks.

Paolo

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