[PATCH 1/1] rtc: gemini: add return value validation

[PATCH 1/1] rtc: gemini: add return value validation

[Pan Bian]

From: Pan Bian <bianpan2016@163.com>

Function devm_ioremap() will return a NULL pointer if it fails to remap
IO address, and its return value should be validated before it is used.
However, in function gemini_rtc_probe(), its return value is not
checked. This may result in bad memory access bugs on future access,
e.g. calling the function gemini_rtc_read_time().

Signed-off-by: Pan Bian <bianpan2016@163.com>
---
 drivers/rtc/rtc-gemini.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/rtc/rtc-gemini.c b/drivers/rtc/rtc-gemini.c
index ccf0dba..5279390 100644
--- a/drivers/rtc/rtc-gemini.c
+++ b/drivers/rtc/rtc-gemini.c
@@ -139,6 +139,8 @@ static int gemini_rtc_probe(struct platform_device *pdev)
 
 	rtc->rtc_base = devm_ioremap(dev, res->start,
 				     resource_size(res));
+	if (!rtc->rtc_base)
+		return -ENOMEM;
 
 	ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt,
 			       IRQF_SHARED, pdev->name, dev);
-- 
1.9.1

[PATCH 1/1] rtc: gemini: add return value validation

[Hans Ulli Kroll]

HI Pan,

On Sun, 23 Apr 2017, Pan Bian wrote:

> From: Pan Bian <bianpan2016@163.com>
> 
> Function devm_ioremap() will return a NULL pointer if it fails to remap
> IO address, and its return value should be validated before it is used.
> However, in function gemini_rtc_probe(), its return value is not
> checked. This may result in bad memory access bugs on future access,
> e.g. calling the function gemini_rtc_read_time().
> 
> Signed-off-by: Pan Bian <bianpan2016@163.com>
> ---
>  drivers/rtc/rtc-gemini.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/rtc/rtc-gemini.c b/drivers/rtc/rtc-gemini.c
> index ccf0dba..5279390 100644
> --- a/drivers/rtc/rtc-gemini.c
> +++ b/drivers/rtc/rtc-gemini.c
> @@ -139,6 +139,8 @@ static int gemini_rtc_probe(struct platform_device *pdev)
>  
>  	rtc->rtc_base = devm_ioremap(dev, res->start,
>  				     resource_size(res));
> +	if (!rtc->rtc_base)
> +		return -ENOMEM;
>  
>  	ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt,
>  			       IRQF_SHARED, pdev->name, dev);
> -- 
> 1.9.1
> 
> 
> 

Acked-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>

[PATCH 1/1] rtc: gemini: add return value validation

[Alexandre Belloni]

On 23/04/2017 at 20:48:07 +0800, Pan Bian wrote:
> From: Pan Bian <bianpan2016@163.com>
> 
> Function devm_ioremap() will return a NULL pointer if it fails to remap
> IO address, and its return value should be validated before it is used.
> However, in function gemini_rtc_probe(), its return value is not
> checked. This may result in bad memory access bugs on future access,
> e.g. calling the function gemini_rtc_read_time().
> 
> Signed-off-by: Pan Bian <bianpan2016@163.com>
> ---
>  drivers/rtc/rtc-gemini.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
Applied, thanks.

-- 
Alexandre Belloni, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com