2021-10-11 16:29:23

by Yang Yingliang

Subject: [PATCH] iio: core: do not create debugfs when has no dev name

I got a null-ptr-deref report when doing fault injection test:

BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: 0000 [#1] SMP KASAN PTI
RIP: 0010:strlen+0x0/0x20
Call Trace:
start_creating+0x199/0x2f0
debugfs_create_dir+0x25/0x430
__iio_device_register+0x4da/0x1b40 [industrialio]
__devm_iio_device_register+0x22/0x80 [industrialio]
max1027_probe+0x639/0x860 [max1027]
spi_probe+0x183/0x210
really_probe+0x285/0xc30

If dev_set_name() fails, the dev_name() is null, add check for
device name before creating debugfs.

Reported-by: Hulk Robot <[email protected]>
Fixes: e553f182d55b ("staging: iio: core: Introduce debugfs support...")
Signed-off-by: Yang Yingliang <[email protected]>
---
drivers/iio/industrialio-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 2dc837db50f7..8974490ad536 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -466,7 +466,7 @@ static void iio_device_register_debugfs(struct iio_dev *indio_dev)
if (indio_dev->info->debugfs_reg_access == NULL)
return;

- if (!iio_debugfs_dentry)
+ if (!iio_debugfs_dentry || !dev_name(&indio_dev->dev))
return;

iio_dev_opaque = to_iio_dev_opaque(indio_dev);
--
2.25.1

2021-10-11 16:37:49

by Lars-Peter Clausen

Subject: Re: [PATCH] iio: core: do not create debugfs when has no dev name

On 10/11/21 3:56 PM, Yang Yingliang wrote:
> I got a null-ptr-deref report when doing fault injection test:
>
> BUG: kernel NULL pointer dereference, address: 0000000000000000
> PGD 0 P4D 0
> Oops: 0000 [#1] SMP KASAN PTI
> RIP: 0010:strlen+0x0/0x20
> Call Trace:
> start_creating+0x199/0x2f0
> debugfs_create_dir+0x25/0x430
> __iio_device_register+0x4da/0x1b40 [industrialio]
> __devm_iio_device_register+0x22/0x80 [industrialio]
> max1027_probe+0x639/0x860 [max1027]
> spi_probe+0x183/0x210
> really_probe+0x285/0xc30
>
> If dev_set_name() fails, the dev_name() is null, add check for
> device name before creating debugfs.

If dev_set_name() fails, shouldn't we better return an error in
iio_device_alloc()? Otherwise the device has no name and will show up as
<null> in sysfs.

>
> Reported-by: Hulk Robot <[email protected]>
> Fixes: e553f182d55b ("staging: iio: core: Introduce debugfs support...")
> Signed-off-by: Yang Yingliang <[email protected]>
> ---
> drivers/iio/industrialio-core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index 2dc837db50f7..8974490ad536 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -466,7 +466,7 @@ static void iio_device_register_debugfs(struct iio_dev *indio_dev)
> if (indio_dev->info->debugfs_reg_access == NULL)
> return;
>
> - if (!iio_debugfs_dentry)
> + if (!iio_debugfs_dentry || !dev_name(&indio_dev->dev))
> return;
>
> iio_dev_opaque = to_iio_dev_opaque(indio_dev);