Re: [PATCH v4 3/3] domctl: Modify XEN_DOMCTL_getdomaininfo to fail if domid is not found

[Jan Beulich <jbeulich@xxxxxxxx>]

On 09.05.2023 18:07, Alejandro Vallejo wrote:
> --- a/xen/common/domctl.c
> +++ b/xen/common/domctl.c
> @@ -314,7 +314,7 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
> u_domctl)
>          /* fall through */
>      default:
>          d = rcu_lock_domain_by_id(op->domain);
> -        if ( !d && op->cmd != XEN_DOMCTL_getdomaininfo )
> +        if ( !d )
>              return -ESRCH;
>      }
>  
> @@ -534,42 +534,14 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
> u_domctl)
>  
>      case XEN_DOMCTL_getdomaininfo:
>      {
> -        domid_t dom = DOMID_INVALID;
> -
> -        if ( !d )
> -        {
> -            ret = -EINVAL;
> -            if ( op->domain >= DOMID_FIRST_RESERVED )
> -                break;
> -
> -            rcu_read_lock(&domlist_read_lock);
> -
> -            dom = op->domain;
> -            for_each_domain ( d )
> -                if ( d->domain_id >= dom )
> -                    break;
> -        }
> -
> -        ret = -ESRCH;
> -        if ( d == NULL )
> -            goto getdomaininfo_out;
> -
>          ret = xsm_getdomaininfo(XSM_HOOK, d);
>          if ( ret )
> -            goto getdomaininfo_out;
> +            break;
>  
>          getdomaininfo(d, &op->u.getdomaininfo);
>  
>          op->domain = op->u.getdomaininfo.domain;
>          copyback = 1;
> -
> -    getdomaininfo_out:
> -        /* When d was non-NULL upon entry, no cleanup is needed. */
> -        if ( dom == DOMID_INVALID )
> -            break;
> -
> -        rcu_read_unlock(&domlist_read_lock);
> -        d = NULL;
>          break;
>      }
>  

I realize it's a little late that this occurs to me, but this being a binary
incompatible change it should imo have been accompanied by a bump of
XEN_DOMCTL_INTERFACE_VERSION (which we haven't bumped yet in this release
cycle).

Jan