[PATCH] drivers: mfd: fix off by one error

[PATCH] drivers: mfd: fix off by one error

[Vasiliy Kulikov]

snprintf() is overflowed iff result is greater or equal than
argument "size".

Signed-off-by: Vasiliy Kulikov <segooon@gmail.com>
---
 Compile tested.

 drivers/mfd/mc13xxx-core.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/mfd/mc13xxx-core.c b/drivers/mfd/mc13xxx-core.c
index 93258ad..cd4d670 100644
--- a/drivers/mfd/mc13xxx-core.c
+++ b/drivers/mfd/mc13xxx-core.c
@@ -696,7 +696,7 @@ static int mc13xxx_add_subdevice_pdata(struct mc13xxx *mc13xxx,
 	};
 
 	/* there is no asnprintf in the kernel :-( */
-	if (snprintf(buf, sizeof(buf), format, name) > sizeof(buf))
+	if (snprintf(buf, sizeof(buf), format, name) >= sizeof(buf))
 		return -E2BIG;
 
 	cell.name = kmemdup(buf, strlen(buf) + 1, GFP_KERNEL);
-- 
1.7.0.4

[PATCH] mfd/mc13xxx: don't open code kasprintf

[@ 2010-10-10 19:39 UTC (permalink / raw)]

This fixes an off by one error noticed by Vasiliy Kulikov en passant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
 drivers/mfd/mc13xxx-core.c |    7 +------
 1 files changed, 1 insertions(+), 6 deletions(-)

diff --git a/drivers/mfd/mc13xxx-core.c b/drivers/mfd/mc13xxx-core.c
index 93258ad..b763b8c 100644
--- a/drivers/mfd/mc13xxx-core.c
+++ b/drivers/mfd/mc13xxx-core.c
@@ -687,7 +687,6 @@ EXPORT_SYMBOL_GPL(mc13783_adc_do_conversion);
 static int mc13xxx_add_subdevice_pdata(struct mc13xxx *mc13xxx,
 		const char *format, void *pdata, size_t pdata_size)
 {
-	char buf[30];
 	const char *name = mc13xxx_get_chipname(mc13xxx);
 
 	struct mfd_cell cell = {
@@ -695,11 +694,7 @@ static int mc13xxx_add_subdevice_pdata(struct mc13xxx *mc13xxx,
 		.data_size = pdata_size,
 	};
 
-	/* there is no asnprintf in the kernel :-( */
-	if (snprintf(buf, sizeof(buf), format, name) > sizeof(buf))
-		return -E2BIG;
-
-	cell.name = kmemdup(buf, strlen(buf) + 1, GFP_KERNEL);
+	cell.name = kasprintf(GFP_KERNEL, format, name);
 	if (!cell.name)
 		return -ENOMEM;
 
-- 
1.7.2.3

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Re: [PATCH] mfd/mc13xxx: don't open code kasprintf

[@ 2010-10-15 13:18 UTC (permalink / raw)]

Hi Samuel,

would you mind to take this patch (or squash it into
0c9b33e5a23e2053165c9e30ffff3b3a3cf1b2b8)?

Thanks
Uwe

On Sun, Oct 10, 2010 at 09:39:46PM +0200, Uwe Kleine-König wrote:
> This fixes an off by one error noticed by Vasiliy Kulikov en passant.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/mfd/mc13xxx-core.c |    7 +------
>  1 files changed, 1 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/mc13xxx-core.c b/drivers/mfd/mc13xxx-core.c
> index 93258ad..b763b8c 100644
> --- a/drivers/mfd/mc13xxx-core.c
> +++ b/drivers/mfd/mc13xxx-core.c
> @@ -687,7 +687,6 @@ EXPORT_SYMBOL_GPL(mc13783_adc_do_conversion);
>  static int mc13xxx_add_subdevice_pdata(struct mc13xxx *mc13xxx,
>  		const char *format, void *pdata, size_t pdata_size)
>  {
> -	char buf[30];
>  	const char *name = mc13xxx_get_chipname(mc13xxx);
>  
>  	struct mfd_cell cell = {
> @@ -695,11 +694,7 @@ static int mc13xxx_add_subdevice_pdata(struct mc13xxx *mc13xxx,
>  		.data_size = pdata_size,
>  	};
>  
> -	/* there is no asnprintf in the kernel :-( */
> -	if (snprintf(buf, sizeof(buf), format, name) > sizeof(buf))
> -		return -E2BIG;
> -
> -	cell.name = kmemdup(buf, strlen(buf) + 1, GFP_KERNEL);
> +	cell.name = kasprintf(GFP_KERNEL, format, name);
>  	if (!cell.name)
>  		return -ENOMEM;
>  
> -- 
> 1.7.2.3
> 
> 

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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Re: [PATCH] mfd/mc13xxx: don't open code kasprintf

[Samuel Ortiz]

Hi Uwe,

On Sun, Oct 10, 2010 at 09:39:46PM +0200, Uwe Kleine-König wrote:
> This fixes an off by one error noticed by Vasiliy Kulikov en passant.
> 
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
>  drivers/mfd/mc13xxx-core.c |    7 +------
>  1 files changed, 1 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/mc13xxx-core.c b/drivers/mfd/mc13xxx-core.c
> index 93258ad..b763b8c 100644
> --- a/drivers/mfd/mc13xxx-core.c
> +++ b/drivers/mfd/mc13xxx-core.c
> @@ -687,7 +687,6 @@ EXPORT_SYMBOL_GPL(mc13783_adc_do_conversion);
>  static int mc13xxx_add_subdevice_pdata(struct mc13xxx *mc13xxx,
>  		const char *format, void *pdata, size_t pdata_size)
>  {
> -	char buf[30];
>  	const char *name = mc13xxx_get_chipname(mc13xxx);
>  
>  	struct mfd_cell cell = {
> @@ -695,11 +694,7 @@ static int mc13xxx_add_subdevice_pdata(struct mc13xxx *mc13xxx,
>  		.data_size = pdata_size,
>  	};
>  
> -	/* there is no asnprintf in the kernel :-( */
> -	if (snprintf(buf, sizeof(buf), format, name) > sizeof(buf))
> -		return -E2BIG;
> -
> -	cell.name = kmemdup(buf, strlen(buf) + 1, GFP_KERNEL);
> +	cell.name = kasprintf(GFP_KERNEL, format, name);
I don't think you need to allocate a name pointer here.
cell.name = mc13xxx_get_chipname(mc13xxx); should be enough as
platform_device_alloc() will memcpy it into an allocated buffer.

Cheers,
Samuel.


>  	if (!cell.name)
>  		return -ENOMEM;
>  
> -- 
> 1.7.2.3
> 

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