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Subject[PATCH v2 2/2] virtio-net: Prevent NULL dereference
Date
This patch prevents a NULL dereference when the user has passed a length
longer than an actual buffer to virtio-net.

Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org
Cc: netdev@vger.kernel.org
Cc: kvm@vger.kernel.org
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
---
drivers/net/virtio_net.c | 12 +++++++++++-
1 files changed, 11 insertions(+), 1 deletions(-)
diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index bde0dec..4a53d2a 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -208,12 +208,22 @@ static struct sk_buff *page_to_skb(struct virtnet_info *vi,
return NULL;
}

- while (len) {
+ while (len && page) {
set_skb_frag(skb, page, offset, &len);
page = (struct page *)page->private;
offset = 0;
}

+ /*
+ * This is the case where we ran out of pages in our linked list, but
+ * supposedly have more data to read.
+ */
+ if (len > 0) {
+ pr_debug("%s: missing data to assemble skb\n", skb->dev->name);
+ dev_kfree_skb(skb);
+ return NULL;
+ }
+
if (page)
give_pages(vi, page);

--
1.7.6.1


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