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Subject[PATCH] reset: Fix potential use-after-free in __of_reset_control_get()
Date
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);

return rstc;
--
2.17.1
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