在 2021/5/25 下午4:45, Yongji Xie 写道:
On Tue, May 25, 2021 at 2:30 PM Jason Wang <jasowang@xxxxxxxxxx> wrote:
在 2021/5/25 下午12:58, Xie Yongji 写道:
This adds validation for used length (might come
from an untrusted device) to avoid data corruption
or loss.
Signed-off-by: Xie Yongji <xieyongji@xxxxxxxxxxxxx>
---
drivers/net/virtio_net.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index c4711e23af88..2dcdc1a3c7e8 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -668,6 +668,13 @@ static struct sk_buff *receive_small(struct net_device *dev,
void *orig_data;
u32 act;
+ if (unlikely(len > GOOD_PACKET_LEN)) {
+ pr_debug("%s: rx error: len %u exceeds max size %lu\n",
+ dev->name, len, GOOD_PACKET_LEN);
+ dev->stats.rx_length_errors++;
+ goto err_xdp;
+ }
Need to count vi->hdr_len here?
We did len -= vi->hdr_len before.
Right.
+
if (unlikely(hdr->hdr.gso_type))
goto err_xdp;
@@ -739,6 +746,14 @@ static struct sk_buff *receive_small(struct net_device *dev,
}
rcu_read_unlock();
+ if (unlikely(len > GOOD_PACKET_LEN)) {
+ pr_debug("%s: rx error: len %u exceeds max size %lu\n",
+ dev->name, len, GOOD_PACKET_LEN);
+ dev->stats.rx_length_errors++;
+ put_page(page);
+ return NULL;
+ }
+
skb = build_skb(buf, buflen);
if (!skb) {
put_page(page);
@@ -822,6 +837,13 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
void *data;
u32 act;
+ 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_xdp;
+ }
There's a similar check after the XDP, let's simply move it here?
Do we still need that in non-XDP cases?
I meant we check once for both XDP and non-XDP if we do it before if
(xdp_prog)
And do we need similar check in receive_big()?
It seems that the check in page_to_skb() can do similar things.
Right.
Thanks
Thanks,
Yongji
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