diff mbox

[2/2] net/hyperv: Fix the page buffer when an RNDIS message goes beyond page boundary

Message ID 1328203080-801-2-git-send-email-haiyangz@microsoft.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Haiyang Zhang Feb. 2, 2012, 5:18 p.m. UTC 
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>
---
 drivers/net/hyperv/netvsc_drv.c   |    8 ++++----
 drivers/net/hyperv/rndis_filter.c |   13 +++++++++++++
 include/linux/hyperv.h            |    2 +-
 3 files changed, 18 insertions(+), 5 deletions(-)

Comments

David Miller Feb. 2, 2012, 7:50 p.m. UTC | #1 
From: Haiyang Zhang <haiyangz@microsoft.com>
Date: Thu,  2 Feb 2012 09:18:00 -0800

> 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>

Applied.
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diff mbox

Patch

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 @@  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 dc2e384..133b7fb 100644
--- 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 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)