[PATCH 4.19 066/105] hwmon: (ibmpex) Fix possible UAF when ibmpex_register_bmc() fails

Greg Kroah-Hartman
2022-12-05T19:22:01Z

From: Gaosheng Cui <cuigaosheng1@huawei.com>

[ Upstream commit e2a87785aab0dac190ac89be6a9ba955e2c634f2 ]

Smatch report warning as follows:

drivers/hwmon/ibmpex.c:509 ibmpex_register_bmc() warn:
'&data->list' not removed from list

If ibmpex_find_sensors() fails in ibmpex_register_bmc(), data will
be freed, but data->list will not be removed from driver_data.bmc_data,
then list traversal may cause UAF.

Fix by removeing it from driver_data.bmc_data before free().

Fixes: 57c7c3a0fdea ("hwmon: IBM power meter driver")
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Link: https://lore.kernel.org/r/20221117034423.2935739-1-cuigaosheng1@huawei.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/ibmpex.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/hwmon/ibmpex.c b/drivers/hwmon/ibmpex.c
index ab72cabf5a95..e289c845f970 100644
--- a/drivers/hwmon/ibmpex.c
+++ b/drivers/hwmon/ibmpex.c
@@ -517,6 +517,7 @@ static void ibmpex_register_bmc(int iface, struct device *dev)
return;

out_register:
+ list_del(&data->list);
hwmon_device_unregister(data->hwmon_dev);
out_user:
ipmi_destroy_user(data->user);
--
2.35.1