Re: [PATCH 1/1] comedi: ni_usb6501: fix transfer-buffer overflows

From: Ian Abbott
Date: Tue Jun 07 2022 - 08:31:10 EST


On 07/06/2022 12:18, Xiaohui Zhang wrote:
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: Xiaohui Zhang <xiaohuizhang@xxxxxxxxxx>
---
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..8303bfc305c5 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_tx), MIN_BUF_SIZE);
devpriv->usb_tx_buf = kzalloc(size, GFP_KERNEL);
if (!devpriv->usb_tx_buf)
return -ENOMEM;

The code change looks OK but this patch should have been sent as a "v2" patch and should have a brief description of the v2 changes after the "---" line.

Reviewed-by: Ian Abbott <abbotti@xxxxxxxxx>

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