[PATCH 5.18 098/102] xen/netfront: fix leaking data in shared pages

Greg Kroah-Hartman
2022-07-05T12:36:36Z

From: Roger Pau Monne <roger.pau@citrix.com>

commit 307c8de2b02344805ebead3440d8feed28f2f010 upstream.

When allocating pages to be used for shared communication with the
backend always zero them, this avoids leaking unintended data present
on the pages.

This is CVE-2022-33740, part of XSA-403.

Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/net/xen-netfront.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -273,7 +273,8 @@ static struct sk_buff *xennet_alloc_one_
if (unlikely(!skb))
return NULL;

- page = page_pool_dev_alloc_pages(queue->page_pool);
+ page = page_pool_alloc_pages(queue->page_pool,
+ GFP_ATOMIC | __GFP_NOWARN | __GFP_ZERO);
if (unlikely(!page)) {
kfree_skb(skb);
return NULL;