lightnvm: fix up nonsensical configure overrun checking
diff mbox

Message ID 20160217140601.3878.33701.stgit@localhost.localdomain
State New
Headers show

Commit Message

Alan Cox Feb. 17, 2016, 2:06 p.m. UTC
Instead of checking a constant 0 actually check the space available. Even
better remember to allow for the header and also check the right amount of
space is needed.

Signed-off-by: Alan Cox <alan@linux.intel.com>
---
 drivers/lightnvm/core.c |   11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)


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Comments

Matias Bjorling Feb. 18, 2016, 7:56 a.m. UTC | #1
On 02/17/2016 03:06 PM, Alan wrote:
> Instead of checking a constant 0 actually check the space available. Even
> better remember to allow for the header and also check the right amount of
> space is needed.
> 
> Signed-off-by: Alan Cox <alan@linux.intel.com>
> ---
>  drivers/lightnvm/core.c |   11 +++++------
>  1 file changed, 5 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
> index 33224cb..782ac5d 100644
> --- a/drivers/lightnvm/core.c
> +++ b/drivers/lightnvm/core.c
> @@ -870,20 +870,19 @@ static int nvm_configure_by_str_event(const char *val,
>  
>  static int nvm_configure_get(char *buf, const struct kernel_param *kp)
>  {
> -	int sz = 0;
> -	char *buf_start = buf;
> +	int sz;
>  	struct nvm_dev *dev;
>  
> -	buf += sprintf(buf, "available devices:\n");
> +	sz = sprintf(buf, "available devices:\n");
>  	down_write(&nvm_lock);
>  	list_for_each_entry(dev, &nvm_devices, devices) {
> -		if (sz > 4095 - DISK_NAME_LEN)
> +		if (sz > 4095 - DISK_NAME_LEN - 2)
>  			break;
> -		buf += sprintf(buf, " %32s\n", dev->name);
> +		sz += sprintf(buf + sz, " %32s\n", dev->name);
>  	}
>  	up_write(&nvm_lock);
>  
> -	return buf - buf_start - 1;
> +	return sz;
>  }
>  
>  static const struct kernel_param_ops nvm_configure_by_str_event_param_ops = {
> 

Thanks Alan, applied.

-Matias
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Patch
diff mbox

diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 33224cb..782ac5d 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -870,20 +870,19 @@  static int nvm_configure_by_str_event(const char *val,
 
 static int nvm_configure_get(char *buf, const struct kernel_param *kp)
 {
-	int sz = 0;
-	char *buf_start = buf;
+	int sz;
 	struct nvm_dev *dev;
 
-	buf += sprintf(buf, "available devices:\n");
+	sz = sprintf(buf, "available devices:\n");
 	down_write(&nvm_lock);
 	list_for_each_entry(dev, &nvm_devices, devices) {
-		if (sz > 4095 - DISK_NAME_LEN)
+		if (sz > 4095 - DISK_NAME_LEN - 2)
 			break;
-		buf += sprintf(buf, " %32s\n", dev->name);
+		sz += sprintf(buf + sz, " %32s\n", dev->name);
 	}
 	up_write(&nvm_lock);
 
-	return buf - buf_start - 1;
+	return sz;
 }
 
 static const struct kernel_param_ops nvm_configure_by_str_event_param_ops = {