[PATCH][V3] usb: isp1760: check for null return from kzalloc

[PATCH][V3] usb: isp1760: check for null return from kzalloc

[Colin King]

From: Colin Ian King <colin.king@canonical.com>

isp1760_ep_alloc_request allocates a structure with kzalloc without checking 
for NULL and then returns a pointer to one of the structure fields. As the 
field happens to be the first in the structure the caller can properly check 
for NULL, but this is risky if the structure layout is changed later. Add an 
explicit NULL check for the kzalloc return value

Detected with smatch static analysis:

drivers/usb/isp1760/isp1760-udc.c:816 isp1760_ep_alloc_request()
  error: potential null dereference 'req'.  (kzalloc returns null)

[ thanks to Laurent Pinchart for improved commit message ]

Signed-off-by: Colin Ian King <colin.king@canonical.com>
---
 drivers/usb/isp1760/isp1760-udc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/isp1760/isp1760-udc.c b/drivers/usb/isp1760/isp1760-udc.c
index 3fc4fe7..18ebf5b 100644
--- a/drivers/usb/isp1760/isp1760-udc.c
+++ b/drivers/usb/isp1760/isp1760-udc.c
@@ -812,6 +812,8 @@ static struct usb_request *isp1760_ep_alloc_request(struct usb_ep *ep,
 	struct isp1760_request *req;
 
 	req = kzalloc(sizeof(*req), gfp_flags);
+	if (!req)
+		return NULL;
 
 	return &req->req;
 }
-- 
2.1.4

Re: [PATCH][V3] usb: isp1760: check for null return from kzalloc

[Laurent Pinchart]

Hi Colin,

Thank you for the patch.

On Tuesday 02 June 2015 19:05:13 Colin King wrote:
> From: Colin Ian King <colin.king@canonical.com>
> 
> isp1760_ep_alloc_request allocates a structure with kzalloc without checking
> for NULL and then returns a pointer to one of the structure fields. As the
> field happens to be the first in the structure the caller can properly
> check for NULL, but this is risky if the structure layout is changed later.
> Add an explicit NULL check for the kzalloc return value
> 
> Detected with smatch static analysis:
> 
> drivers/usb/isp1760/isp1760-udc.c:816 isp1760_ep_alloc_request()
>   error: potential null dereference 'req'.  (kzalloc returns null)
> 
> [ thanks to Laurent Pinchart for improved commit message ]
> 
> Signed-off-by: Colin Ian King <colin.king@canonical.com>

Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

Felipe, I expect you to pick this up, please let me know if there's any issue.

> ---
>  drivers/usb/isp1760/isp1760-udc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/usb/isp1760/isp1760-udc.c
> b/drivers/usb/isp1760/isp1760-udc.c index 3fc4fe7..18ebf5b 100644
> --- a/drivers/usb/isp1760/isp1760-udc.c
> +++ b/drivers/usb/isp1760/isp1760-udc.c
> @@ -812,6 +812,8 @@ static struct usb_request
> *isp1760_ep_alloc_request(struct usb_ep *ep, struct isp1760_request *req;
> 
>  	req = kzalloc(sizeof(*req), gfp_flags);
> +	if (!req)
> +		return NULL;
> 
>  	return &req->req;
>  }

-- 
Regards,

Laurent Pinchart

Re: [PATCH][V3] usb: isp1760: check for null return from kzalloc

[Felipe Balbi]

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Hi,

On Wed, Jun 03, 2015 at 03:43:23AM +0300, Laurent Pinchart wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > isp1760_ep_alloc_request allocates a structure with kzalloc without checking
> > for NULL and then returns a pointer to one of the structure fields. As the
> > field happens to be the first in the structure the caller can properly
> > check for NULL, but this is risky if the structure layout is changed later.
> > Add an explicit NULL check for the kzalloc return value
> > 
> > Detected with smatch static analysis:
> > 
> > drivers/usb/isp1760/isp1760-udc.c:816 isp1760_ep_alloc_request()
> >   error: potential null dereference 'req'.  (kzalloc returns null)
> > 
> > [ thanks to Laurent Pinchart for improved commit message ]
> > 
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> 
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> Felipe, I expect you to pick this up, please let me know if there's any issue.

once -rc1 is tagged, yes. My tree is already closed for v4.2.

-- 
balbi

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Re: [PATCH][V3] usb: isp1760: check for null return from kzalloc

[Greg Kroah-Hartman]

On Wed, Jun 03, 2015 at 03:43:23AM +0300, Laurent Pinchart wrote:
> Hi Colin,
> 
> Thank you for the patch.
> 
> On Tuesday 02 June 2015 19:05:13 Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> > 
> > isp1760_ep_alloc_request allocates a structure with kzalloc without checking
> > for NULL and then returns a pointer to one of the structure fields. As the
> > field happens to be the first in the structure the caller can properly
> > check for NULL, but this is risky if the structure layout is changed later.
> > Add an explicit NULL check for the kzalloc return value
> > 
> > Detected with smatch static analysis:
> > 
> > drivers/usb/isp1760/isp1760-udc.c:816 isp1760_ep_alloc_request()
> >   error: potential null dereference 'req'.  (kzalloc returns null)
> > 
> > [ thanks to Laurent Pinchart for improved commit message ]
> > 
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> 
> Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> 
> Felipe, I expect you to pick this up, please let me know if there's any issue.

I'll just take it directly, thanks.

greg k-h

Re: [PATCH][V3] usb: isp1760: check for null return from kzalloc

[Felipe Balbi]

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On Mon, Jun 08, 2015 at 02:22:06PM -0700, Greg Kroah-Hartman wrote:
> On Wed, Jun 03, 2015 at 03:43:23AM +0300, Laurent Pinchart wrote:
> > Hi Colin,
> > 
> > Thank you for the patch.
> > 
> > On Tuesday 02 June 2015 19:05:13 Colin King wrote:
> > > From: Colin Ian King <colin.king@canonical.com>
> > > 
> > > isp1760_ep_alloc_request allocates a structure with kzalloc without checking
> > > for NULL and then returns a pointer to one of the structure fields. As the
> > > field happens to be the first in the structure the caller can properly
> > > check for NULL, but this is risky if the structure layout is changed later.
> > > Add an explicit NULL check for the kzalloc return value
> > > 
> > > Detected with smatch static analysis:
> > > 
> > > drivers/usb/isp1760/isp1760-udc.c:816 isp1760_ep_alloc_request()
> > >   error: potential null dereference 'req'.  (kzalloc returns null)
> > > 
> > > [ thanks to Laurent Pinchart for improved commit message ]
> > > 
> > > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > 
> > Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > 
> > Felipe, I expect you to pick this up, please let me know if there's any issue.
> 
> I'll just take it directly, thanks.

that works too, dropping from my queue.

-- 
balbi

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