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Commit 5c7c179e authored by Marek Marczykowski-Górecki's avatar Marek Marczykowski-Górecki Committed by Greg Kroah-Hartman
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x86/xen: allow userspace access during hypercalls 



commit c54590cac51db8ab5fd30156bdaba34af915e629 upstream.

Userspace application can do a hypercall through /dev/xen/privcmd, and
some for some hypercalls argument is a pointers to user-provided
structure. When SMAP is supported and enabled, hypervisor can't access.
So, lets allow it.

The same applies to HYPERVISOR_dm_op, where additionally privcmd driver
carefully verify buffer addresses.

Cc: stable@vger.kernel.org
Signed-off-by: default avatarMarek Marczykowski-Górecki <marmarek@invisiblethingslab.com>
Reviewed-by: default avatarJuergen Gross <jgross@suse.com>
[HYPERVISOR_dm_op dropped - not present until 4.11]
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 78dce99f

arch/x86/include/asm/xen/hypercall.h

+3 −0
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ 


#include <asm/page.h>

#include <asm/pgtable.h>

#include <asm/smap.h>



#include <xen/interface/xen.h>

#include <xen/interface/sched.h>
@@ -213,10 +214,12 @@ privcmd_call(unsigned call, 
	__HYPERCALL_DECLS;

	__HYPERCALL_5ARG(a1, a2, a3, a4, a5);



	stac();

	asm volatile("call *%[call]"

		     : __HYPERCALL_5PARAM

		     : [call] "a" (&hypercall_page[call])

		     : __HYPERCALL_CLOBBER5);

	clac();



	return (long)__res;

}