net/hyperv: Fix the page buffer when an RNDIS message goes beyond page boundary
There is a possible data corruption if an RNDIS message goes beyond page
boundary in the sending code path. This patch fixes the problem.
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 69193fc..466c58a 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -151,10 +151,10 @@
int ret;
unsigned int i, num_pages, npg_data;
- /* Add multipage for skb->data and additional one for RNDIS */
+ /* Add multipages for skb->data and additional 2 for RNDIS */
npg_data = (((unsigned long)skb->data + skb_headlen(skb) - 1)
>> PAGE_SHIFT) - ((unsigned long)skb->data >> PAGE_SHIFT) + 1;
- num_pages = skb_shinfo(skb)->nr_frags + npg_data + 1;
+ num_pages = skb_shinfo(skb)->nr_frags + npg_data + 2;
/* Allocate a netvsc packet based on # of frags. */
packet = kzalloc(sizeof(struct hv_netvsc_packet) +
@@ -173,8 +173,8 @@
sizeof(struct hv_netvsc_packet) +
(num_pages * sizeof(struct hv_page_buffer));
- /* Setup the rndis header */
- packet->page_buf_cnt = num_pages;
+ /* If the rndis msg goes beyond 1 page, we will add 1 later */
+ packet->page_buf_cnt = num_pages - 1;
/* Initialize it from the skb */
packet->total_data_buflen = skb->len;