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

[Pathak, Rahul (R.)]

Hello Alan,

Should I resend  this patch version  with the tear line correction?

Regards
Rahul Pathak


________________________________________
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Sent: Tuesday, December 8, 2015 8:53 PM
To: Pathak, Rahul (R.)
Cc: gregkh@xxxxxxxxxxxxxxxxxxx; kborer@xxxxxxxxx; dan.carpenter@xxxxxxxxxx; chasemetzger15@xxxxxxxxx; linux-usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Subject: Re: [PATCH v2] usb: Use memdup_user to reuse the code

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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