On Mon, Jul 24, 2017 at 04:45:02PM -0700, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > The patch below was submitted to be applied to the 4.12-stable tree. > > I fail to see how this patch meets the stable kernel rules as found at > Documentation/process/stable_kernel_rules.rst. > > I could be totally wrong, and if so, please respond to > <stable@xxxxxxxxxxxxxxx> and let me know why this patch should be > applied. Otherwise, it is now dropped from my patch queues, never to be > seen again. This is a fix for -EFAULT on (any?) usage of /dev/xen/privcmd from inside of Xen HVM guest with SMAP enabled. Details in this thread: http://markmail.org/message/b6wxaipxbjyhiueg > thanks, > > greg k-h > > ------------------ original commit in Linus's tree ------------------ > > From c54590cac51db8ab5fd30156bdaba34af915e629 Mon Sep 17 00:00:00 2001 > From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?= > <marmarek@xxxxxxxxxxxxxxxxxxxxxx> > Date: Mon, 26 Jun 2017 14:49:46 +0200 > Subject: [PATCH] x86/xen: allow userspace access during hypercalls > MIME-Version: 1.0 > Content-Type: text/plain; charset=UTF-8 > Content-Transfer-Encoding: 8bit > > 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@xxxxxxxxxxxxxxx > Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx> > Reviewed-by: Juergen Gross <jgross@xxxxxxxx> > Signed-off-by: Juergen Gross <jgross@xxxxxxxx> > > diff --git a/arch/x86/include/asm/xen/hypercall.h b/arch/x86/include/asm/xen/hypercall.h > index 7a4db5fefd15..11071fcd630e 100644 > --- a/arch/x86/include/asm/xen/hypercall.h > +++ b/arch/x86/include/asm/xen/hypercall.h > @@ -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> > @@ -216,10 +217,12 @@ 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; > } > @@ -478,7 +481,11 @@ static inline int > HYPERVISOR_dm_op( > domid_t dom, unsigned int nr_bufs, struct xen_dm_op_buf *bufs) > { > - return _hypercall3(int, dm_op, dom, nr_bufs, bufs); > + int ret; > + stac(); > + ret = _hypercall3(int, dm_op, dom, nr_bufs, bufs); > + clac(); > + return ret; > } > > static inline void > -- Best Regards, Marek Marczykowski-Górecki Invisible Things Lab A: Because it messes up the order in which people normally read text. Q: Why is top-posting such a bad thing?
Attachment:
signature.asc
Description: PGP signature