diff mbox series

[v2] virtio-net: Add validation for used length

Message ID 20210527073643.123-1-xieyongji@bytedance.com
State New
Headers show
Series [v2] virtio-net: Add validation for used length | expand

Commit Message

Yongji Xie May 27, 2021, 7:36 a.m. UTC 
This adds validation for used length (might come
from an untrusted device) to avoid data corruption
or loss.

Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
 drivers/net/virtio_net.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

Comments

Yongji Xie May 28, 2021, 3:10 a.m. UTC | #1 
On Fri, May 28, 2021 at 2:07 AM Jakub Kicinski <kuba@kernel.org> wrote:
>

> On Thu, 27 May 2021 15:36:43 +0800 Xie Yongji wrote:

> > This adds validation for used length (might come

> > from an untrusted device) to avoid data corruption

> > or loss.

> >

> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>

>

> This does not apply to net nor net-next.


Will send v3. Thanks for the reminder.

Thanks,
Yongji
diff mbox series

Patch

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c4711e23af88..01f10049f686 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -661,6 +661,17 @@  static struct sk_buff *receive_small(struct net_device *dev,
 
 	rcu_read_lock();
 	xdp_prog = rcu_dereference(rq->xdp_prog);
+	if (unlikely(len > GOOD_PACKET_LEN)) {
+		pr_debug("%s: rx error: len %u exceeds max size %d\n",
+			 dev->name, len, GOOD_PACKET_LEN);
+		dev->stats.rx_length_errors++;
+		if (xdp_prog)
+			goto err_xdp;
+
+		rcu_read_unlock();
+		put_page(page);
+		return NULL;
+	}
 	if (xdp_prog) {
 		struct virtio_net_hdr_mrg_rxbuf *hdr = buf + header_offset;
 		struct xdp_frame *xdpf;
@@ -815,6 +826,16 @@  static struct sk_buff *receive_mergeable(struct net_device *dev,
 
 	rcu_read_lock();
 	xdp_prog = rcu_dereference(rq->xdp_prog);
+	if (unlikely(len > truesize)) {
+		pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
+			 dev->name, len, (unsigned long)ctx);
+		dev->stats.rx_length_errors++;
+		if (xdp_prog)
+			goto err_xdp;
+
+		rcu_read_unlock();
+		goto err_skb;
+	}
 	if (xdp_prog) {
 		struct xdp_frame *xdpf;
 		struct page *xdp_page;
@@ -937,13 +958,6 @@  static struct sk_buff *receive_mergeable(struct net_device *dev,
 	}
 	rcu_read_unlock();
 
-	if (unlikely(len > truesize)) {
-		pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
-			 dev->name, len, (unsigned long)ctx);
-		dev->stats.rx_length_errors++;
-		goto err_skb;
-	}
-
 	head_skb = page_to_skb(vi, rq, page, offset, len, truesize, !xdp_prog,
 			       metasize);
 	curr_skb = head_skb;