[PATCH] USB: io_edgeport: fix slab-out-of-bounds Read in edge_interrupt_callback

Qiujun Huang
2020-03-25T07:52:44Z

The boundary condition should be (length - 1) as we access data[position+1].

Reported-and-tested-by: syzbot+37ba33391ad5f3935bbd@syzkaller.appspotmail.com
Signed-off-by: Qiujun Huang <hqjagain@gmail.com>
---
drivers/usb/serial/io_edgeport.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index 5737add..4cca0b8 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -710,7 +710,7 @@ static void edge_interrupt_callback(struct urb *urb)
/* grab the txcredits for the ports if available */
position = 2;
portNumber = 0;
- while ((position < length) &&
+ while ((position < length - 1) &&
(portNumber < edge_serial->serial->num_ports)) {
txCredits = data[position] | (data[position+1] << 8);
if (txCredits) {
--
1.8.3.1