[SRU][F][PATCH 0/1] CVE-2020-36776

[Bethany Jamison]

[Impact]

 In the Linux kernel, the following vulnerability has been resolved:

 thermal/drivers/cpufreq_cooling: Fix slab OOB issue

 Slab OOB issue is scanned by KASAN in cpu_power_to_freq().
 If power is limited below the power of OPP0 in EM table,
 it will cause slab out-of-bound issue with negative array
 index.

 Return the lowest frequency if limited power cannot found
 a suitable OPP in EM table to fix this issue.

 Backtrace:
 [<ffffffd02d2a37f0>] die+0x104/0x5ac
 [<ffffffd02d2a5630>] bug_handler+0x64/0xd0
 [<ffffffd02d288ce4>] brk_handler+0x160/0x258
 [<ffffffd02d281e5c>] do_debug_exception+0x248/0x3f0
 [<ffffffd02d284488>] el1_dbg+0x14/0xbc
 [<ffffffd02d75d1d4>] __kasan_report+0x1dc/0x1e0
 [<ffffffd02d75c2e0>] kasan_report+0x10/0x20
 [<ffffffd02d75def8>] __asan_report_load8_noabort+0x18/0x28
 [<ffffffd02e6fce5c>] cpufreq_power2state+0x180/0x43c
 [<ffffffd02e6ead80>] power_actor_set_power+0x114/0x1d4
 [<ffffffd02e6fac24>] allocate_power+0xaec/0xde0
 [<ffffffd02e6f9f80>] power_allocator_throttle+0x3ec/0x5a4
 [<ffffffd02e6ea888>] handle_thermal_trip+0x160/0x294
 [<ffffffd02e6edd08>] thermal_zone_device_check+0xe4/0x154
 [<ffffffd02d351cb4>] process_one_work+0x5e4/0xe28
 [<ffffffd02d352f44>] worker_thread+0xa4c/0xfac
 [<ffffffd02d360124>] kthread+0x33c/0x358
 [<ffffffd02d289940>] ret_from_fork+0xc/0x18

[Fix]

Mantic:	not-affected
Jammy: 	not-affected
Focal: 	Backported - The fix commit changes the range of a for-loop,
	but Focal's for-loop was set up differently than upstream (decrementing
	instead of incrementing) so I modified the range of the for-loop to
	match the fix commit (0, max_level].
Bionic: Backported - being sent out via esm ML.
Xenial: not-affected
Trusty: not-affected

[Test Case]

Compile and boot tested.

[Where problems could occur]

This affectes those using the cpufreq_cooling thermal driver, issues could 
occur in memory management if this out-of-bounds issue causes power to be
too low in the CPU.

brian-sy yang (1):
  thermal/drivers/cpufreq_cooling: Fix slab OOB issue

 drivers/thermal/cpu_cooling.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

-- 
2.34.1