Patch-mainline: v6.3

Git-commit: 853618d5886bf94812f31228091cd37d308230f7

References: git-fixes

From: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

Date: Fri, 14 Apr 2023 14:08:35 +0800

Subject: [PATCH] virtio_net: bugfix overflow inside xdp_linearize_page()

Here we copy the data from the original buf to the new page. But we

not check that it may be overflow.

As long as the size received(including vnethdr) is greater than 3840

(PAGE_SIZE -VIRTIO_XDP_HEADROOM). Then the memcpy will overflow.

And this is completely possible, as long as the MTU is large, such

as 4096. In our test environment, this will cause crash. Since crash is

caused by the written memory, it is meaningless, so I do not include it.

Fixes: 72979a6c3590 ("virtio_net: xdp, add slowpath case for non contiguous buffers")

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>

Acked-by: Jason Wang <jasowang@redhat.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Juergen Gross <jgross@suse.com>

---

 drivers/net/virtio_net.c | 8 ++++++--

 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c

index 2396c28c0122..ea1bd4bb326d 100644

--- a/drivers/net/virtio_net.c

+++ b/drivers/net/virtio_net.c

@@ -814,8 +814,13 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,

 				       int page_off,

 				       unsigned int *len)

 {

-	struct page *page = alloc_page(GFP_ATOMIC);

+	int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

+	struct page *page;

+

+	if (page_off + *len + tailroom > PAGE_SIZE)

+		return NULL;

+	page = alloc_page(GFP_ATOMIC);

 	if (!page)

 		return NULL;

@@ -823,7 +828,6 @@ static struct page *xdp_linearize_page(struct receive_queue *rq,

 	page_off += *len;

 	while (--*num_buf) {

-		int tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));

 		unsigned int buflen;

 		void *buf;

 		int off;

-- 

2.35.3