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From:   Xiaohui Zhang <ruc_zhangxiaohui@163.com>
To:     Xiaohui Zhang <ruc_zhangxiaohui@163.com>,
        Ian Abbott <abbotti@mev.co.uk>,
        H Hartley Sweeten <hsweeten@visionengravers.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Johan Hovold <johan@kernel.org>, linux-kernel@vger.kernel.org
Subject: [PATCH 1/1] comedi: ni_usb6501: fix transfer-buffer overflows
Date:   Sun,  5 Jun 2022 20:43:22 +0800
Message-Id: <20220605124322.33148-1-ruc_zhangxiaohui@163.com>
Precedence: bulk

From: xiaohuizhang98 <ruc_zhangxiaohui@163.com>

We detected a suspected bug with our code clone detection tool.

Similar to the handling of vmk80xx_alloc_usb_buffers in commit
a23461c47482("comedi: vmk80xx: fix transfer-buffer overflows"),
we thought a patch might be needed here as well.

The driver uses endpoint-sized USB transfer buffers but up until
recently had no sanity checks on the sizes.

Signed-off-by: xiaohuizhang98 <ruc_zhangxiaohui@163.com>
---
 drivers/comedi/drivers/ni_usb6501.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/comedi/drivers/ni_usb6501.c b/drivers/comedi/drivers/ni_usb6501.c
index 0dd9edf7bced..3e2b9f4d840b 100644
--- a/drivers/comedi/drivers/ni_usb6501.c
+++ b/drivers/comedi/drivers/ni_usb6501.c
@@ -90,6 +90,7 @@
 #include <linux/comedi/comedi_usb.h>
 
 #define	NI6501_TIMEOUT	1000
+#define MIN_BUF_SIZE	64
 
 /* Port request packets */
 static const u8 READ_PORT_REQUEST[]	= {0x00, 0x01, 0x00, 0x10,
@@ -459,12 +460,12 @@ static int ni6501_alloc_usb_buffers(struct comedi_device *dev)
 	struct ni6501_private *devpriv = dev->private;
 	size_t size;
 
-	size = usb_endpoint_maxp(devpriv->ep_rx);
+	size = max(usb_endpoint_maxp(devpriv->ep_rx), MIN_BUF_SIZE);
 	devpriv->usb_rx_buf = kzalloc(size, GFP_KERNEL);
 	if (!devpriv->usb_rx_buf)
 		return -ENOMEM;
 
-	size = usb_endpoint_maxp(devpriv->ep_tx);
+	size = max(usb_endpoint_maxp(devpriv->ep_rx), MIN_BUF_SIZE);
 	devpriv->usb_tx_buf = kzalloc(size, GFP_KERNEL);
 	if (!devpriv->usb_tx_buf)
 		return -ENOMEM;
-- 
2.17.1