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

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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>
This commit is contained in:
Haiyang Zhang 2012-02-02 07:18:00 +00:00 committed by David S. Miller
parent 0a282538cc
commit c31c151b1c
3 changed files with 18 additions and 5 deletions
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8
drivers/net/hyperv/netvsc_drv.c
View file

@ -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;

13
drivers/net/hyperv/rndis_filter.c
View file

@ -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 =

2
include/linux/hyperv.h
View file

@ -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)