Patch "virtio: 9p: correctly pass physical address to userspace for high pages" has been added to the 3.7-stable tree

Patch "virtio: 9p: correctly pass physical address to userspace for high pages" has been added to the 3.7-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    virtio: 9p: correctly pass physical address to userspace for high pages

to the 3.7-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     virtio-9p-correctly-pass-physical-address-to-userspace-for-high-pages.patch
and it can be found in the queue-3.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From b9cdc88df8e63e81c723b82c286fc97f5d0dc325 Mon Sep 17 00:00:00 2001
From: Will Deacon <will.deacon@arm.com>
Date: Fri, 19 Oct 2012 14:03:32 +0100
Subject: virtio: 9p: correctly pass physical address to userspace for high pages

From: Will Deacon <will.deacon@arm.com>

commit b9cdc88df8e63e81c723b82c286fc97f5d0dc325 upstream.

When using a virtio transport, the 9p net device may pass the physical
address of a kernel buffer to userspace via a scatterlist inside a
virtqueue. If the kernel buffer is mapped outside of the linear mapping
(e.g. highmem), then virt_to_page will return a bogus value and we will
populate the scatterlist with junk.

This patch uses kmap_to_page when populating the page array for a kernel
buffer.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/9p/trans_virtio.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/9p/trans_virtio.c
+++ b/net/9p/trans_virtio.c
@@ -39,6 +39,7 @@
 #include <linux/inet.h>
 #include <linux/idr.h>
 #include <linux/file.h>
+#include <linux/highmem.h>
 #include <linux/slab.h>
 #include <net/9p/9p.h>
 #include <linux/parser.h>
@@ -325,7 +326,7 @@ static int p9_get_mapped_pages(struct vi
 		int count = nr_pages;
 		while (nr_pages) {
 			s = rest_of_page(data);
-			pages[index++] = virt_to_page(data);
+			pages[index++] = kmap_to_page(data);
 			data += s;
 			nr_pages--;
 		}


Patches currently in stable-queue which might be from will.deacon@arm.com are

queue-3.7/mm-highmem-export-kmap_to_page-for-modules.patch
queue-3.7/arm64-signal-push-the-unwinding-prologue-on-the-signal-stack.patch
queue-3.7/virtio-9p-correctly-pass-physical-address-to-userspace-for-high-pages.patch
queue-3.7/virtio-force-vring-descriptors-to-be-allocated-from-lowmem.patch