From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Cooper Subject: Re: [PATCH 02/22] libxc: introduce xc_dom_seg_to_ptr_pages Date: Tue, 11 Jun 2013 19:44:29 +0100 Message-ID: <51B7700D.1060706@citrix.com> References: <1370974865-19554-1-git-send-email-ian.jackson@eu.citrix.com> <1370974865-19554-3-git-send-email-ian.jackson@eu.citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1370974865-19554-3-git-send-email-ian.jackson@eu.citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Jackson Cc: "xen-devel@lists.xensource.com" , "mattjd@gmail.com" , "security@xen.org" List-Id: xen-devel@lists.xenproject.org On 11/06/13 19:20, Ian Jackson wrote: > Provide a version of xc_dom_seg_to_ptr which returns the number of > guest pages it has actually mapped. This is useful for callers who > want to do range checking; we will use this later in this series. > > This is part of the fix to a security issue, XSA-55. > > Signed-off-by: Ian Jackson Reviewed-by: Andrew Cooper > > v7: xc_dom_seg_to_ptr_pages now always expects pages_out!=NULL. > (It seems silly to have it tolerate NULL when all the real callers > pass non-NULL and there's a version which doesn't need pages_out > anyway. Fix the call in xc_dom_seg_to_ptr to have a dummy pages > for pages_out.) > > v5: xc_dom_seg_to_ptr_pages sets *pages_out=0 if it returns NULL. > > v4 was: > > Acked-by: Ian Campbell > Reviewed-by: Konrad Rzeszutek Wilk > --- > tools/libxc/xc_dom.h | 19 ++++++++++++++++--- > 1 files changed, 16 insertions(+), 3 deletions(-) > > diff --git a/tools/libxc/xc_dom.h b/tools/libxc/xc_dom.h > index ac36600..316c5cb 100644 > --- a/tools/libxc/xc_dom.h > +++ b/tools/libxc/xc_dom.h > @@ -294,14 +294,27 @@ void *xc_dom_pfn_to_ptr(struct xc_dom_image *dom, xen_pfn_t first, > void xc_dom_unmap_one(struct xc_dom_image *dom, xen_pfn_t pfn); > void xc_dom_unmap_all(struct xc_dom_image *dom); > > -static inline void *xc_dom_seg_to_ptr(struct xc_dom_image *dom, > - struct xc_dom_seg *seg) > +static inline void *xc_dom_seg_to_ptr_pages(struct xc_dom_image *dom, > + struct xc_dom_seg *seg, > + xen_pfn_t *pages_out) > { > xen_vaddr_t segsize = seg->vend - seg->vstart; > unsigned int page_size = XC_DOM_PAGE_SIZE(dom); > xen_pfn_t pages = (segsize + page_size - 1) / page_size; > + void *retval; > + > + retval = xc_dom_pfn_to_ptr(dom, seg->pfn, pages); > + > + *pages_out = retval ? pages : 0; > + return retval; > +} > + > +static inline void *xc_dom_seg_to_ptr(struct xc_dom_image *dom, > + struct xc_dom_seg *seg) > +{ > + xen_pfn_t dummy; > > - return xc_dom_pfn_to_ptr(dom, seg->pfn, pages); > + return xc_dom_seg_to_ptr_pages(dom, seg, &dummy); > } > > static inline void *xc_dom_vaddr_to_ptr(struct xc_dom_image *dom,