[PATCH V2 1/1] comedi: ni_usb6501: fix transfer-buffer overflows

[PATCH V2 1/1] comedi: ni_usb6501: fix transfer-buffer overflows

[Xiaohui Zhang]

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.

---

Fix the typo in the last bit of the old patch which use the wrong
endpoint to determine the size for usb_tx_buf.

Signed-off-by: Xiaohui Zhang <xiaohuizhang@ruc.edu.cn>
---
 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;
-- 
2.17.1

Re: [PATCH V2 1/1] comedi: ni_usb6501: fix transfer-buffer overflows

[Greg Kroah-Hartman]

On Tue, Jun 07, 2022 at 09:47:20PM +0800, 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.
> 
> ---
> 
> Fix the typo in the last bit of the old patch which use the wrong
> endpoint to determine the size for usb_tx_buf.
> 
> Signed-off-by: Xiaohui Zhang <xiaohuizhang@ruc.edu.cn>
> ---

Please read the documentation links I sent you that say how to properly
document this.

Please do so and then you can submit a v3.

thanks,

greg k-h