netdev - [PATCH AUTOSEL 4.19 42/43] usbnet: sanity checking of packet sizes and device mtu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [day] [month] [year] [list]

Message-Id: <20191001164311.15993-42-sashal@kernel.org>
Date:   Tue,  1 Oct 2019 12:43:10 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Oliver Neukum <oneukum@...e.com>,
        "David S . Miller" <davem@...emloft.net>,
        Sasha Levin <sashal@...nel.org>, netdev@...r.kernel.org,
        linux-usb@...r.kernel.org
Subject: [PATCH AUTOSEL 4.19 42/43] usbnet: sanity checking of packet sizes and device mtu

From: Oliver Neukum <oneukum@...e.com>

[ Upstream commit 280ceaed79f18db930c0cc8bb21f6493490bf29c ]

After a reset packet sizes and device mtu can change and need
to be reevaluated to calculate queue sizes.
Malicious devices can set this to zero and we divide by it.
Introduce sanity checking.

Reported-and-tested-by:  syzbot+6102c120be558c885f04@...kaller.appspotmail.com
Signed-off-by: Oliver Neukum <oneukum@...e.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/net/usb/usbnet.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 52ffb2360cc90..84b354f76dea8 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -356,6 +356,8 @@ void usbnet_update_max_qlen(struct usbnet *dev)
 {
 	enum usb_device_speed speed = dev->udev->speed;
 
+	if (!dev->rx_urb_size || !dev->hard_mtu)
+		goto insanity;
 	switch (speed) {
 	case USB_SPEED_HIGH:
 		dev->rx_qlen = MAX_QUEUE_MEMORY / dev->rx_urb_size;
@@ -372,6 +374,7 @@ void usbnet_update_max_qlen(struct usbnet *dev)
 		dev->tx_qlen = 5 * MAX_QUEUE_MEMORY / dev->hard_mtu;
 		break;
 	default:
+insanity:
 		dev->rx_qlen = dev->tx_qlen = 4;
 	}
 }
-- 
2.20.1