Re: [PATCH v2] usb: Use memdup_user to reuse the code

From: Alan Stern
Date: Tue Dec 08 2015 - 10:23:17 EST


On Tue, 8 Dec 2015, Pathak, Rahul (R.) wrote:

> From: Rahul Pathak <rpathak@xxxxxxxxxxx>
>
> Fixing coccicheck warning which recommends to use memdup_user instead
> to reimplement its code, using memdup_user simplifies the code
>
> ./drivers/usb/core/devio.c:1398:11-18: WARNING opportunity for memdup_user
>
> Changes after v1: setting isopkt=NULL for proper kfree() call

This line belongs below the "---" tear line, so that it doesn't show up
in the final commit changelog. People reading the final commit won't
care about earlier versions of the patch.

> Signed-off-by: Rahul Pathak <rpathak@xxxxxxxxxxx>
> ---
> drivers/usb/core/devio.c | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
> index 38ae877c..844407c 100644
> --- a/drivers/usb/core/devio.c
> +++ b/drivers/usb/core/devio.c
> @@ -1395,11 +1395,10 @@ static int proc_do_submiturb(struct usb_dev_state *ps, struct usbdevfs_urb *uurb
> number_of_packets = uurb->number_of_packets;
> isofrmlen = sizeof(struct usbdevfs_iso_packet_desc) *
> number_of_packets;
> - isopkt = kmalloc(isofrmlen, GFP_KERNEL);
> - if (!isopkt)
> - return -ENOMEM;
> - if (copy_from_user(isopkt, iso_frame_desc, isofrmlen)) {
> - ret = -EFAULT;
> + isopkt = memdup_user(iso_frame_desc, isofrmlen);
> + if (IS_ERR(isopkt)) {
> + ret = PTR_ERR(isopkt);
> + isopkt = NULL;
> goto error;
> }
> for (totlen = u = 0; u < number_of_packets; u++) {

Aside from that,

Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

Alan Stern

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