[PATCH 5.5 206/399] net: phy: fixed_phy: fix use-after-free when checking link GPIO

Greg Kroah-Hartman
2020-02-21T07:52:27Z

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

[ Upstream commit d266f19f3ae7fbcaf92229639b78d2110ae44f33 ]

If we fail to locate GPIO for any reason other than deferral or
not-found-GPIO, we try to print device tree node info, however if might
be freed already as we called of_node_put() on it.

Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/phy/fixed_phy.c | 7 ++-----
1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/fixed_phy.c b/drivers/net/phy/fixed_phy.c
index 7c5265fd2b94d..4190f9ed5313d 100644
--- a/drivers/net/phy/fixed_phy.c
+++ b/drivers/net/phy/fixed_phy.c
@@ -212,16 +212,13 @@ static struct gpio_desc *fixed_phy_get_gpiod(struct device_node *np)
*/
gpiod = gpiod_get_from_of_node(fixed_link_node, "link-gpios", 0,
GPIOD_IN, "mdio");
- of_node_put(fixed_link_node);
- if (IS_ERR(gpiod)) {
- if (PTR_ERR(gpiod) == -EPROBE_DEFER)
- return gpiod;
-
+ if (IS_ERR(gpiod) && PTR_ERR(gpiod) != -EPROBE_DEFER) {
if (PTR_ERR(gpiod) != -ENOENT)
pr_err("error getting GPIO for fixed link %pOF, proceed without\n",
fixed_link_node);
gpiod = NULL;
}
+ of_node_put(fixed_link_node);

return gpiod;
}
--
2.20.1