xenoprof: clear buffer intended to be shared with guests

alloc_xenheap_pages() making use of MEMF_no_scrub is fine for Xen
internally used allocations, but buffers allocated to be shared with
(unpriviliged) guests need to be zapped of their prior content.

This is part of XSA-313.

Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wl@xen.org>

diff --git a/xen/common/xenoprof.c b/xen/common/xenoprof.c
index 4f3e799ebbcfd2eae8db3efb3192abc6d3382d9e..4d909fd5d69bf67446b8ac6177bd975f2ca716c3 100644 (file)
--- a/xen/common/xenoprof.c
+++ b/xen/common/xenoprof.c
@@ -253,6 +253,9 @@ static int alloc_xenoprof_struct(
         return -ENOMEM;
     }
 
+    for ( i = 0; i < npages; ++i )
+        clear_page(d->xenoprof->rawbuf + i * PAGE_SIZE);
+
     d->xenoprof->npages = npages;
     d->xenoprof->nbuf = nvcpu;
     d->xenoprof->bufsize = bufsize;