在 2021/5/31 下午9:58, 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 <[email protected]>
Acked-by: Jason Wang <[email protected]>
---
drivers/net/virtio_net.c | 20 +++++++++++++-------
1 file changed, 13 insertions(+), 7 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 073fec4c0df1..ed969b65126e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -730,6 +730,12 @@ static struct sk_buff *receive_small(struct net_device
*dev,
len -= vi->hdr_len;
stats->bytes += len;
+ 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++;
+ goto err_len;
+ }
rcu_read_lock();
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
@@ -833,6 +839,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
err_xdp:
rcu_read_unlock();
stats->xdp_drops++;
+err_len:
stats->drops++;
put_page(page);
xdp_xmit:
@@ -886,6 +893,12 @@ static struct sk_buff *receive_mergeable(struct net_device
*dev,
head_skb = NULL;
stats->bytes += len - vi->hdr_len;
+ 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;
+ }
rcu_read_lock();
xdp_prog = rcu_dereference(rq->xdp_prog);
if (xdp_prog) {
@@ -1012,13 +1025,6 @@ 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, !!headroom);
curr_skb = head_skb;
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