r8152: fix tx/rx memory overflow

[Linux-MTD Mailing List]

Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=7937f9e5141c9d4864d399d91325605a35cd5831
Commit:     7937f9e5141c9d4864d399d91325605a35cd5831
Parent:     b4789b8e6be3151a955ade74872822f30e8cd914
Author:     hayeswang <hayeswang at realtek.com>
AuthorDate: Wed Nov 20 17:30:54 2013 +0800
Committer:  David S. Miller <davem at davemloft.net>
CommitDate: Wed Nov 20 15:09:41 2013 -0500

    r8152: fix tx/rx memory overflow
    
    The tx/rx would access the memory which is out of the desired range.
    Modify the method of checking the end of the memory to avoid it.
    
    For r8152_tx_agg_fill(), the variable remain may become negative.
    However, the declaration is unsigned, so the while loop wouldn't
    break when reaching the end of the desied memory. Although to change
    the declaration from unsigned to signed is enough to fix it, I also
    modify the checking method for safe. Replace
    
    		remain = rx_buf_sz - sizeof(*tx_desc) -
    			 (u32)((void *)tx_data - agg->head);
    
    with
    
    		remain = rx_buf_sz - (int)(tx_agg_align(tx_data) - agg->head);
    
    to make sure the variable remain is always positive. Then, the
    overflow wouldn't happen.
    
    For rx_bottom(), the rx_desc should not be used to calculate the
    packet length before making sure the rx_desc is in the desired range.
    Change the checking to two parts. First, check the descriptor is in
    the memory. The other, using the descriptor to find out the packet
    length and check if the packet is in the memory.
    
    Signed-off-by: Hayes Wang <hayeswang at realtek.com>
    Signed-off-by: David S. Miller <davem at davemloft.net>
---
 drivers/net/usb/r8152.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index f3fce41..428600d 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -24,7 +24,7 @@
 #include <linux/ipv6.h>
 
 /* Version Information */
-#define DRIVER_VERSION "v1.01.0 (2013/08/12)"
+#define DRIVER_VERSION "v1.02.0 (2013/10/28)"
 #define DRIVER_AUTHOR "Realtek linux nic maintainers <nic_swsd at realtek.com>"
 #define DRIVER_DESC "Realtek RTL8152 Based USB 2.0 Ethernet Adapters"
 #define MODULENAME "r8152"
@@ -1136,14 +1136,14 @@ r8152_tx_csum(struct r8152 *tp, struct tx_desc *desc, struct sk_buff *skb)
 
 static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
 {
-	u32 remain;
+	int remain;
 	u8 *tx_data;
 
 	tx_data = agg->head;
 	agg->skb_num = agg->skb_len = 0;
-	remain = rx_buf_sz - sizeof(struct tx_desc);
+	remain = rx_buf_sz;
 
-	while (remain >= ETH_ZLEN) {
+	while (remain >= ETH_ZLEN + sizeof(struct tx_desc)) {
 		struct tx_desc *tx_desc;
 		struct sk_buff *skb;
 		unsigned int len;
@@ -1152,12 +1152,14 @@ static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
 		if (!skb)
 			break;
 
+		remain -= sizeof(*tx_desc);
 		len = skb->len;
 		if (remain < len) {
 			skb_queue_head(&tp->tx_queue, skb);
 			break;
 		}
 
+		tx_data = tx_agg_align(tx_data);
 		tx_desc = (struct tx_desc *)tx_data;
 		tx_data += sizeof(*tx_desc);
 
@@ -1167,9 +1169,8 @@ static int r8152_tx_agg_fill(struct r8152 *tp, struct tx_agg *agg)
 		agg->skb_len += len;
 		dev_kfree_skb_any(skb);
 
-		tx_data = tx_agg_align(tx_data + len);
-		remain = rx_buf_sz - sizeof(*tx_desc) -
-			 (u32)((void *)tx_data - agg->head);
+		tx_data += len;
+		remain = rx_buf_sz - (int)(tx_agg_align(tx_data) - agg->head);
 	}
 
 	usb_fill_bulk_urb(agg->urb, tp->udev, usb_sndbulkpipe(tp->udev, 2),
@@ -1188,7 +1189,6 @@ static void rx_bottom(struct r8152 *tp)
 	list_for_each_safe(cursor, next, &tp->rx_done) {
 		struct rx_desc *rx_desc;
 		struct rx_agg *agg;
-		unsigned pkt_len;
 		int len_used = 0;
 		struct urb *urb;
 		u8 *rx_data;
@@ -1204,17 +1204,22 @@ static void rx_bottom(struct r8152 *tp)
 
 		rx_desc = agg->head;
 		rx_data = agg->head;
-		pkt_len = le32_to_cpu(rx_desc->opts1) & RX_LEN_MASK;
-		len_used += sizeof(struct rx_desc) + pkt_len;
+		len_used += sizeof(struct rx_desc);
 
-		while (urb->actual_length >= len_used) {
+		while (urb->actual_length > len_used) {
 			struct net_device *netdev = tp->netdev;
 			struct net_device_stats *stats;
+			unsigned int pkt_len;
 			struct sk_buff *skb;
 
+			pkt_len = le32_to_cpu(rx_desc->opts1) & RX_LEN_MASK;
 			if (pkt_len < ETH_ZLEN)
 				break;
 
+			len_used += pkt_len;
+			if (urb->actual_length < len_used)
+				break;
+
 			stats = rtl8152_get_stats(netdev);
 
 			pkt_len -= 4; /* CRC */
@@ -1234,9 +1239,8 @@ static void rx_bottom(struct r8152 *tp)
 
 			rx_data = rx_agg_align(rx_data + pkt_len + 4);
 			rx_desc = (struct rx_desc *)rx_data;
-			pkt_len = le32_to_cpu(rx_desc->opts1) & RX_LEN_MASK;
 			len_used = (int)(rx_data - (u8 *)agg->head);
-			len_used += sizeof(struct rx_desc) + pkt_len;
+			len_used += sizeof(struct rx_desc);
 		}
 
 submit: