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 69193fcb7648700da8b41cee49b0e10ae15edf6f..466c58a7353dba30e89d8986c58e7cf7550b7670 100644 (file)
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -151,10 +151,10 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
        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 @@ static int netvsc_start_xmit(struct sk_buff *skb, struct net_device *net)
                                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 dc2e3849573be406999f3d123b7d47b7c85ef2e1..133b7fbf8595b423792a675f3ff5b9317106ef78 100644 (file)
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -797,6 +797,19 @@ int rndis_filter_send(struct hv_device *dev,
                        (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 62b908e0e5910a2863a0f623f3dede3a3b0bebb1..0ae065a5fcb2775540a012e7710e25b84fef81ff 100644 (file)
--- 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)