Re: [patch v2] libertas: potential oops in debugfs

[Dan Williams <dcbw@redhat.com>]

On Wed, 2013-10-30 at 20:12 +0300, Dan Carpenter wrote:
> If we do a zero size allocation then it will oops.  Also we can't be
> sure the user passes us a NUL terminated string so I've added a
> terminator.
> 
> This code can only be triggered by root.
> 
> Reported-by: Nico Golde <nico@ngolde.de>
> Reported-by: Fabian Yamaguchi <fabs@goesec.de>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Acked-by: Dan Williams <dcbw@redhat.com>

> 
> diff --git a/drivers/net/wireless/libertas/debugfs.c b/drivers/net/wireless/libertas/debugfs.c
> index 668dd27..1917348 100644
> --- a/drivers/net/wireless/libertas/debugfs.c
> +++ b/drivers/net/wireless/libertas/debugfs.c
> @@ -913,7 +913,10 @@ static ssize_t lbs_debugfs_write(struct file *f, const char __user *buf,
>  	char *p2;
>  	struct debug_data *d = f->private_data;
>  
> -	pdata = kmalloc(cnt, GFP_KERNEL);
> +	if (cnt == 0)
> +		return 0;
> +
> +	pdata = kmalloc(cnt + 1, GFP_KERNEL);
>  	if (pdata == NULL)
>  		return 0;
>  
> @@ -922,6 +925,7 @@ static ssize_t lbs_debugfs_write(struct file *f, const char __user *buf,
>  		kfree(pdata);
>  		return 0;
>  	}
> +	pdata[cnt] = '\0';
>  
>  	p0 = pdata;
>  	for (i = 0; i < num_of_items; i++) {
> --
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