Subject: patch "staging: comedi: check validity of wMaxPacketSize of usb endpoints" added to staging-testing
To:     anant.thazhemadam@gmail.com, gregkh@linuxfoundation.org,
        stable@vger.kernel.org
From:   <gregkh@linuxfoundation.org>
Date:   Sat, 10 Oct 2020 12:37:55 +0200
Message-ID: <160232627519420@kroah.com>
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This is a note to let you know that I've just added the patch titled

    staging: comedi: check validity of wMaxPacketSize of usb endpoints

to my staging git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-testing 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 be merged to the staging-next branch sometime soon,
after it passes testing, and the merge window is open.

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


From e1f13c879a7c21bd207dc6242455e8e3a1e88b40 Mon Sep 17 00:00:00 2001
From: Anant Thazhemadam <anant.thazhemadam@gmail.com>
Date: Sat, 10 Oct 2020 13:59:32 +0530
Subject: staging: comedi: check validity of wMaxPacketSize of usb endpoints
 found

While finding usb endpoints in vmk80xx_find_usb_endpoints(), check if
wMaxPacketSize = 0 for the endpoints found.

Some devices have isochronous endpoints that have wMaxPacketSize = 0
(as required by the USB-2 spec).
However, since this doesn't apply here, wMaxPacketSize = 0 can be
considered to be invalid.

Reported-by: syzbot+009f546aa1370056b1c2@syzkaller.appspotmail.com
Tested-by: syzbot+009f546aa1370056b1c2@syzkaller.appspotmail.com
Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20201010082933.5417-1-anant.thazhemadam@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/staging/comedi/drivers/vmk80xx.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/staging/comedi/drivers/vmk80xx.c b/drivers/staging/comedi/drivers/vmk80xx.c
index 65dc6c51037e..7956abcbae22 100644
--- a/drivers/staging/comedi/drivers/vmk80xx.c
+++ b/drivers/staging/comedi/drivers/vmk80xx.c
@@ -667,6 +667,9 @@ static int vmk80xx_find_usb_endpoints(struct comedi_device *dev)
 	if (!devpriv->ep_rx || !devpriv->ep_tx)
 		return -ENODEV;
 
+	if (!usb_endpoint_maxp(devpriv->ep_rx) || !usb_endpoint_maxp(devpriv->ep_tx))
+		return -EINVAL;
+
 	return 0;
 }
 
-- 
2.28.0