[PATCH v2] drivers/base/auxiliary: check return value of strrchr()

[PATCH v2] drivers/base/auxiliary: check return value of strrchr()

[Li Zhong]

The return value of strrchr() could be NULL, which will cause invalid
offset in (int)(p - name). So we check it here.

Signed-off-by: Li Zhong <floridsleeves@gmail.com>
---
 drivers/base/auxiliary.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c
index 8c5e65930617..2ec0306bfba3 100644
--- a/drivers/base/auxiliary.c
+++ b/drivers/base/auxiliary.c
@@ -191,6 +191,8 @@ static int auxiliary_uevent(struct device *dev, struct kobj_uevent_env *env)
 
 	name = dev_name(dev);
 	p = strrchr(name, '.');
+	if (!p)
+		return -EINVAL;
 
 	return add_uevent_var(env, "MODALIAS=%s%.*s", AUXILIARY_MODULE_PREFIX,
 			      (int)(p - name), name);
-- 
2.25.1

Re: [PATCH v2] drivers/base/auxiliary: check return value of strrchr()

[Greg KH]

On Sat, Sep 03, 2022 at 05:51:56PM -0700, Li Zhong wrote:
> The return value of strrchr() could be NULL, which will cause invalid
> offset in (int)(p - name). So we check it here.
> 
> Signed-off-by: Li Zhong <floridsleeves@gmail.com>
> ---
>  drivers/base/auxiliary.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/base/auxiliary.c b/drivers/base/auxiliary.c
> index 8c5e65930617..2ec0306bfba3 100644
> --- a/drivers/base/auxiliary.c
> +++ b/drivers/base/auxiliary.c
> @@ -191,6 +191,8 @@ static int auxiliary_uevent(struct device *dev, struct kobj_uevent_env *env)
>  
>  	name = dev_name(dev);
>  	p = strrchr(name, '.');
> +	if (!p)
> +		return -EINVAL;

How can that ever happen?  For what device will that be triggered?

And again, please follow Documentation/process/researcher-guidelines.rst