CVE-2021-47441

In the Linux kernel, the following vulnerability has been resolved: mlxsw:
thermal: Fix out-of-bounds memory accesses Currently, mlxsw allows cooling
states to be set above the maximum cooling state supported by the driver: #
cat /sys/class/thermal/thermal_zone2/cdev0/type mlxsw_fan # cat
/sys/class/thermal/thermal_zone2/cdev0/max_state 10 # echo 18 >
/sys/class/thermal/thermal_zone2/cdev0/cur_state # echo $? 0 This results
in out-of-bounds memory accesses when thermal state transition statistics
are enabled (CONFIG_THERMAL_STATISTICS=y), as the transition table is
accessed with a too large index (state) [1]. According to the thermal
maintainer, it is the responsibility of the driver to reject such
operations [2]. Therefore, return an error when the state to be set exceeds
the maximum cooling state supported by the driver. To avoid dead code, as
suggested by the thermal maintainer [3], partially revert commit
a421ce088ac8 (“mlxsw: core: Extend cooling device with cooling levels”)
that tried to interpret these invalid cooling states (above the maximum) in
a special way. The cooling levels array is not removed in order to prevent
the fans going below 20% PWM, which would cause them to get stuck at 0%
PWM. [1] BUG: KASAN: slab-out-of-bounds in
thermal_cooling_device_stats_update+0x271/0x290 Read of size 4 at addr
ffff8881052f7bf8 by task kworker/0:0/5 CPU: 0 PID: 5 Comm: kworker/0:0 Not
tainted 5.15.0-rc3-custom-45935-gce1adf704b14 #122 Hardware name: Mellanox
Technologies Ltd. “MSN2410-CB2FO”/“SA000874”, BIOS 4.6.5 03/08/2016
Workqueue: events_freezable_power_ thermal_zone_device_check Call Trace:
dump_stack_lvl+0x8b/0xb3 print_address_description.constprop.0+0x1f/0x140
kasan_report.cold+0x7f/0x11b
thermal_cooling_device_stats_update+0x271/0x290
__thermal_cdev_update+0x15e/0x4e0 thermal_cdev_update+0x9f/0xe0
step_wise_throttle+0x770/0xee0 thermal_zone_device_update+0x3f6/0xdf0
process_one_work+0xa42/0x1770 worker_thread+0x62f/0x13e0
kthread+0x3ee/0x4e0 ret_from_fork+0x1f/0x30 Allocated by task 1:
kasan_save_stack+0x1b/0x40 __kasan_kmalloc+0x7c/0x90
thermal_cooling_device_setup_sysfs+0x153/0x2c0
__thermal_cooling_device_register.part.0+0x25b/0x9c0
thermal_cooling_device_register+0xb3/0x100 mlxsw_thermal_init+0x5c5/0x7e0
__mlxsw_core_bus_device_register+0xcb3/0x19c0
mlxsw_core_bus_device_register+0x56/0xb0 mlxsw_pci_probe+0x54f/0x710
local_pci_probe+0xc6/0x170 pci_device_probe+0x2b2/0x4d0
really_probe+0x293/0xd10 __driver_probe_device+0x2af/0x440
driver_probe_device+0x51/0x1e0 __driver_attach+0x21b/0x530
bus_for_each_dev+0x14c/0x1d0 bus_add_driver+0x3ac/0x650
driver_register+0x241/0x3d0 mlxsw_sp_module_init+0xa2/0x174
do_one_initcall+0xee/0x5f0 kernel_init_freeable+0x45a/0x4de
kernel_init+0x1f/0x210 ret_from_fork+0x1f/0x30 The buggy address belongs to
the object at ffff8881052f7800 which belongs to the cache kmalloc-1k of
size 1024 The buggy address is located 1016 bytes inside of 1024-byte
region [ffff8881052f7800, ffff8881052f7c00) The buggy address belongs to
the page: page:0000000052355272 refcount:1 mapcount:0
mapping:0000000000000000 index:0x0 pfn:0x1052f0 head:0000000052355272
order:3 compound_mapcount:0 compound_pincount:0 flags:
0x200000000010200(slab|head|node=0|zone=2) raw: 0200000000010200
ffffea0005034800 0000000300000003 ffff888100041dc0 raw: 0000000000000000
0000000000100010 00000001ffffffff 0000000000000000 page dumped because:
kasan: bad access detected Memory state around the buggy address:
ffff8881052f7a80: 00 00 00 00 00 00 04 fc fc fc fc fc fc fc fc fc
ffff8881052f7b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8881052f7b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc ^
ffff8881052f7c00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8881052f7c80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc [2]
https://lore.kernel.org/linux-pm/9aca37cb-1629-5c67- —truncated—