xen/netfront: fix leaking data in shared pages

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>

diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c
index 2492a27..cae8537 100644 (file)
--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -273,7 +273,8 @@ static struct sk_buff *xennet_alloc_one_rx_buffer(struct netfront_queue *queue)
        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;