2019-03-18 23:25:31

by Aditya Pakki

Subject: [PATCH] mtd: rawnand: vf610: Fix to check for NULL pointer dereference

of_match_device can return NULL if there is no matching device is found.
The patch avoids a potential NULL pointer dereference by checking for the
return value and passing the error upstream.

Signed-off-by: Aditya Pakki <[email protected]>
---
drivers/mtd/nand/raw/vf610_nfc.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/mtd/nand/raw/vf610_nfc.c b/drivers/mtd/nand/raw/vf610_nfc.c
index a662ca1970e5..946abbb275c3 100644
--- a/drivers/mtd/nand/raw/vf610_nfc.c
+++ b/drivers/mtd/nand/raw/vf610_nfc.c
@@ -850,6 +850,8 @@ static int vf610_nfc_probe(struct platform_device *pdev)
}

of_id = of_match_device(vf610_nfc_dt_ids, &pdev->dev);
+ if (!of_id)
+ return -ENODEV;
nfc->variant = (enum vf610_nfc_variant)of_id->data;

for_each_available_child_of_node(nfc->dev->of_node, child) {
--
2.17.1

2019-04-01 15:27:46

by Miquel Raynal

Subject: Re: [PATCH] mtd: rawnand: vf610: Fix to check for NULL pointer dereference

Hi Aditya,

Aditya Pakki <[email protected]> wrote on Mon, 18 Mar 2019 18:24:34
-0500:

> of_match_device can return NULL if there is no matching device is found.
> The patch avoids a potential NULL pointer dereference by checking for the
> return value and passing the error upstream.
>
> Signed-off-by: Aditya Pakki <[email protected]>
> ---
> drivers/mtd/nand/raw/vf610_nfc.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/mtd/nand/raw/vf610_nfc.c b/drivers/mtd/nand/raw/vf610_nfc.c
> index a662ca1970e5..946abbb275c3 100644
> --- a/drivers/mtd/nand/raw/vf610_nfc.c
> +++ b/drivers/mtd/nand/raw/vf610_nfc.c
> @@ -850,6 +850,8 @@ static int vf610_nfc_probe(struct platform_device *pdev)
> }
>
> of_id = of_match_device(vf610_nfc_dt_ids, &pdev->dev);
> + if (!of_id)
> + return -ENODEV;
> nfc->variant = (enum vf610_nfc_variant)of_id->data;
>
> for_each_available_child_of_node(nfc->dev->of_node, child) {


Applied to git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git
on nand/next with the title changed to

mtd: rawnand: vf610: Avoid a potential NULL pointer dereference

and a space after the return statement.

Thanks,
Miquèl

2019-04-01 15:32:23

by Boris Brezillon

Subject: Re: [PATCH] mtd: rawnand: vf610: Fix to check for NULL pointer dereference

On Mon, 1 Apr 2019 17:26:51 +0200
Miquel Raynal <[email protected]> wrote:

> Hi Aditya,
>
> Aditya Pakki <[email protected]> wrote on Mon, 18 Mar 2019 18:24:34
> -0500:
>
> > of_match_device can return NULL if there is no matching device is found.
> > The patch avoids a potential NULL pointer dereference by checking for the
> > return value and passing the error upstream.
> >
> > Signed-off-by: Aditya Pakki <[email protected]>
> > ---
> > drivers/mtd/nand/raw/vf610_nfc.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/mtd/nand/raw/vf610_nfc.c b/drivers/mtd/nand/raw/vf610_nfc.c
> > index a662ca1970e5..946abbb275c3 100644
> > --- a/drivers/mtd/nand/raw/vf610_nfc.c
> > +++ b/drivers/mtd/nand/raw/vf610_nfc.c
> > @@ -850,6 +850,8 @@ static int vf610_nfc_probe(struct platform_device *pdev)
> > }
> >
> > of_id = of_match_device(vf610_nfc_dt_ids, &pdev->dev);
> > + if (!of_id)
> > + return -ENODEV;

For the record, this can't happen unless you have serious memory
corruption issues since you reached the ->probe() function (which means
a match was found before).

> > nfc->variant = (enum vf610_nfc_variant)of_id->data;
> >
> > for_each_available_child_of_node(nfc->dev->of_node, child) {
>
>
> Applied to git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git
> on nand/next with the title changed to
>
> mtd: rawnand: vf610: Avoid a potential NULL pointer dereference
>
> and a space after the return statement.
>
> Thanks,
> Miquèl