There is a risk that the members of the structure asix_rx_fixup_info
become unsynchronised leading to the possibility of a malfunction.
For example, rx->split_head was not being set to false after an
error was detected so potentially could cause a malformed 32-bit
Data header word to be formed.
Therefore add function reset_asix_rx_fixup_info() to reset all the
members of asix_rx_fixup_info so that future processing will start
with known initial conditions.
Also, if (skb->len != offset) becomes true then call
reset_asix_rx_fixup_info() so that the processing of the next URB
starts with known initial conditions. Without the call, the check
does nothing which potentially could lead to a malfunction
when the next URB is processed.
In addition, for robustness, call reset_asix_rx_fixup_info() before
every error path's "return 0". This ensures that the next URB is
processed from known initial conditions.
Signed-off-by: Dean Jenkins <dean_jenk...@mentor.com>
---
drivers/net/usb/asix_common.c | 34 +++++++++++++++++++++++++---------
1 file changed, 25 insertions(+), 9 deletions(-)
diff --git a/drivers/net/usb/asix_common.c b/drivers/net/usb/asix_common.c
index 6983b6b..fda74f3 100644
--- a/drivers/net/usb/asix_common.c
+++ b/drivers/net/usb/asix_common.c
@@ -75,6 +75,27 @@ void asix_write_cmd_async(struct usbnet *dev, u8 cmd, u16
value, u16 index,
value, index, data, size);
}
+static void reset_asix_rx_fixup_info(struct asix_rx_fixup_info *rx)
+{
+ /* Reset the variables that have a lifetime outside of
+ * asix_rx_fixup_internal() so that future processing starts from a
+ * known set of initial conditions.
+ */
+
+ if (rx->ax_skb) {
+ /* Discard any incomplete Ethernet frame in the netdev buffer */
+ kfree_skb(rx->ax_skb);
+ rx->ax_skb = NULL;
+ }
+
+ /* Assume the Data header 32-bit word is at the start of the current
+ * or next URB socket buffer so reset all the state variables.
+ */
+ rx->remaining = 0;
+ rx->split_head = false;
+ rx->header = 0;
+}
+
int asix_rx_fixup_internal(struct usbnet *dev, struct sk_buff *skb,
struct asix_rx_fixup_info *rx)
{
@@ -99,15 +120,7 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct
sk_buff *skb,
if (size != ((~rx->header >> 16) & 0x7ff)) {
netdev_err(dev->net, "asix_rx_fixup() Data Header
synchronisation was lost, remaining %d\n",
rx->remaining);
- if (rx->ax_skb) {
- kfree_skb(rx->ax_skb);
- rx->ax_skb = NULL;
- /* Discard the incomplete netdev Ethernet frame
- * and assume the Data header is at the start of
- * the current URB socket buffer.
- */
- }
- rx->remaining = 0;
+ reset_asix_rx_fixup_info(rx);
}
}
@@ -139,11 +152,13 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct
sk_buff *skb,
if (size != ((~rx->header >> 16) & 0x7ff)) {
netdev_err(dev->net, "asix_rx_fixup() Bad
Header Length 0x%x, offset %d\n",
rx->header, offset);
+ reset_asix_rx_fixup_info(rx);
return 0;
}
if (size > dev->net->mtu + ETH_HLEN + VLAN_HLEN) {
netdev_dbg(dev->net, "asix_rx_fixup() Bad RX
Length %d\n",
size);
+ reset_asix_rx_fixup_info(rx);
return 0;
}
@@ -180,6 +195,7 @@ int asix_rx_fixup_internal(struct usbnet *dev, struct
sk_buff *skb,
if (skb->len != offset) {
netdev_err(dev->net, "asix_rx_fixup() Bad SKB Length %d, %d\n",
skb->len, offset);
+ reset_asix_rx_fixup_info(rx);
return 0;
}
--
2.7.4
--
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