[PATCH 5.10 439/452] thermal/core: fix a UAF bug in __thermal_cooling_device_register()
From: Greg Kroah-Hartman
Date: Tue Jun 07 2022 - 14:11:47 EST
From: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
commit 0a5c26712f963f0500161a23e0ffff8d29f742ab upstream.
When device_register() return failed, program will goto out_kfree_type
to release 'cdev->device' by put_device(). That will call thermal_release()
to free 'cdev'. But the follow-up processes access 'cdev' continually.
That trggers the UAF bug.
====================================================================
BUG: KASAN: use-after-free in __thermal_cooling_device_register+0x75b/0xa90
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
dump_stack_lvl+0xe2/0x152
print_address_description.constprop.0+0x21/0x140
? __thermal_cooling_device_register+0x75b/0xa90
kasan_report.cold+0x7f/0x11b
? __thermal_cooling_device_register+0x75b/0xa90
__thermal_cooling_device_register+0x75b/0xa90
? memset+0x20/0x40
? __sanitizer_cov_trace_pc+0x1d/0x50
? __devres_alloc_node+0x130/0x180
devm_thermal_of_cooling_device_register+0x67/0xf0
max6650_probe.cold+0x557/0x6aa
......
Freed by task 258:
kasan_save_stack+0x1b/0x40
kasan_set_track+0x1c/0x30
kasan_set_free_info+0x20/0x30
__kasan_slab_free+0x109/0x140
kfree+0x117/0x4c0
thermal_release+0xa0/0x110
device_release+0xa7/0x240
kobject_put+0x1ce/0x540
put_device+0x20/0x30
__thermal_cooling_device_register+0x731/0xa90
devm_thermal_of_cooling_device_register+0x67/0xf0
max6650_probe.cold+0x557/0x6aa [max6650]
Do not use 'cdev' again after put_device() to fix the problem like doing
in thermal_zone_device_register().
[dlezcano]: as requested by Rafael, change the affectation into two statements.
Fixes: 584837618100 ("thermal/drivers/core: Use a char pointer for the cooling device name")
Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Link: https://lore.kernel.org/r/20211015024504.947520-1-william.xuanziyang@xxxxxxxxxx
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/thermal/thermal_core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/thermal/thermal_core.c
+++ b/drivers/thermal/thermal_core.c
@@ -1092,7 +1092,7 @@ __thermal_cooling_device_register(struct
{
struct thermal_cooling_device *cdev;
struct thermal_zone_device *pos = NULL;
- int ret;
+ int id, ret;
if (!ops || !ops->get_max_state || !ops->get_cur_state ||
!ops->set_cur_state)
@@ -1106,6 +1106,7 @@ __thermal_cooling_device_register(struct
if (ret < 0)
goto out_kfree_cdev;
cdev->id = ret;
+ id = ret;
cdev->type = kstrdup(type ? type : "", GFP_KERNEL);
if (!cdev->type) {
@@ -1147,8 +1148,9 @@ out_kfree_type:
thermal_cooling_device_destroy_sysfs(cdev);
kfree(cdev->type);
put_device(&cdev->device);
+ cdev = NULL;
out_ida_remove:
- ida_simple_remove(&thermal_cdev_ida, cdev->id);
+ ida_simple_remove(&thermal_cdev_ida, id);
out_kfree_cdev:
return ERR_PTR(ret);
}