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;
diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index dc2e384..133b7fb 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -797,6 +797,19 @@
(unsigned long)rndisMessage & (PAGE_SIZE-1);
pkt->page_buf[0].len = rndisMessageSize;
+ /* Add one page_buf if the rndis msg goes beyond page boundary */
+ if (pkt->page_buf[0].offset + rndisMessageSize > PAGE_SIZE) {
+ int i;
+ for (i = pkt->page_buf_cnt; i > 1; i--)
+ pkt->page_buf[i] = pkt->page_buf[i-1];
+ pkt->page_buf_cnt++;
+ pkt->page_buf[0].len = PAGE_SIZE - pkt->page_buf[0].offset;
+ pkt->page_buf[1].pfn = virt_to_phys((void *)((ulong)
+ rndisMessage + pkt->page_buf[0].len)) >> PAGE_SHIFT;
+ pkt->page_buf[1].offset = 0;
+ pkt->page_buf[1].len = rndisMessageSize - pkt->page_buf[0].len;
+ }
+
/* Save the packet send completion and context */
filterPacket->completion = pkt->completion.send.send_completion;
filterPacket->completion_ctx =
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 62b908e..0ae065a 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -35,7 +35,7 @@
#include <linux/mod_devicetable.h>
-#define MAX_PAGE_BUFFER_COUNT 18
+#define MAX_PAGE_BUFFER_COUNT 19
#define MAX_MULTIPAGE_BUFFER_COUNT 32 /* 128K */
#pragma pack(push, 1)