Commit bf6f66de authored by Marek Marczykowski-Górecki's avatar Marek Marczykowski-Górecki Committed by Sasha Levin

x86/xen: allow userspace access during hypercalls

[ Upstream commit c54590ca ]

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>
Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent 1799763d
...@@ -43,6 +43,7 @@ ...@@ -43,6 +43,7 @@
#include <asm/page.h> #include <asm/page.h>
#include <asm/pgtable.h> #include <asm/pgtable.h>
#include <asm/smap.h>
#include <xen/interface/xen.h> #include <xen/interface/xen.h>
#include <xen/interface/sched.h> #include <xen/interface/sched.h>
...@@ -213,10 +214,12 @@ privcmd_call(unsigned call, ...@@ -213,10 +214,12 @@ privcmd_call(unsigned call,
__HYPERCALL_DECLS; __HYPERCALL_DECLS;
__HYPERCALL_5ARG(a1, a2, a3, a4, a5); __HYPERCALL_5ARG(a1, a2, a3, a4, a5);
stac();
asm volatile("call *%[call]" asm volatile("call *%[call]"
: __HYPERCALL_5PARAM : __HYPERCALL_5PARAM
: [call] "a" (&hypercall_page[call]) : [call] "a" (&hypercall_page[call])
: __HYPERCALL_CLOBBER5); : __HYPERCALL_CLOBBER5);
clac();
return (long)__res; return (long)__res;
} }
......
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