patch "USB: serial: io_edgeport: fix slab-out-of-bounds read in" added to usb-next

patch "USB: serial: io_edgeport: fix slab-out-of-bounds read in" added to usb-next

[gregkh]

This is a note to let you know that I've just added the patch titled

    USB: serial: io_edgeport: fix slab-out-of-bounds read in

to my usb git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-next branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will also be merged in the next major kernel release
during the merge window.

If you have any questions about this process, please let me know.


From 57aa9f294b09463492f604feaa5cc719beaace32 Mon Sep 17 00:00:00 2001
From: Qiujun Huang <hqjagain@gmail.com>
Date: Wed, 25 Mar 2020 15:52:37 +0800
Subject: USB: serial: io_edgeport: fix slab-out-of-bounds read in
 edge_interrupt_callback

Fix slab-out-of-bounds read in the interrupt-URB completion handler.

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>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
---
 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 5737add6a2a4..4cca0b836f43 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) {
-- 
2.26.0