lkml.org 
[lkml]   [2018]   [Oct]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] reset: Fix potential use-after-free in __of_reset_control_get()
From
Date
Hi Geert,

On Mon, 2018-10-08 at 13:14 +0200, Geert Uytterhoeven wrote:
> Calling of_node_put() decreases the reference count of a device tree
> object, and may free some data.
>
> However, the of_phandle_args structure embedding it is passed to
> reset_controller_dev.of_xlate() after that, so it may still be accessed.
>
> Move the call to of_node_put() down to fix this.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> ---
> drivers/reset/core.c | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/reset/core.c b/drivers/reset/core.c
> index 225e34c56b94a2e3..bc9df10d31b4bae1 100644
> --- a/drivers/reset/core.c
> +++ b/drivers/reset/core.c
> @@ -496,27 +496,28 @@ struct reset_control *__of_reset_control_get(struct device_node *node,
> break;
> }
> }
> - of_node_put(args.np);
>
> if (!rcdev) {
> - mutex_unlock(&reset_list_mutex);
> - return ERR_PTR(-EPROBE_DEFER);
> + rstc = ERR_PTR(-EPROBE_DEFER);
> + goto out;
> }
>
> if (WARN_ON(args.args_count != rcdev->of_reset_n_cells)) {
> - mutex_unlock(&reset_list_mutex);
> - return ERR_PTR(-EINVAL);
> + rstc = ERR_PTR(-EINVAL);
> + goto out;
> }
>
> rstc_id = rcdev->of_xlate(rcdev, &args);
> if (rstc_id < 0) {
> - mutex_unlock(&reset_list_mutex);
> - return ERR_PTR(rstc_id);
> + rstc = ERR_PTR(rstc_id);
> + goto out;
> }
>
> /* reset_list_mutex also protects the rcdev's reset_control list */
> rstc = __reset_control_get_internal(rcdev, rstc_id, shared);
>
> +out:
> + of_node_put(args.np);
> mutex_unlock(&reset_list_mutex);

Thank you for the patch. I'd like to move of_node_put after mutex_unlock
for symmetry. If you agree, I can switch the two when applying.

regards
Philipp

\
 
 \ /
  Last update: 2018-10-08 14:57    [W:0.037 / U:0.756 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site