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

Dan Williams
2013-10-30T19:52:25Z

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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