mlxsw: thermal: Fix out-of-bounds memory accesses

PlaidCat · PlaidCat · commit 4bb3978ac87f · 2025-06-06T13:31:52.000-04:00
jira LE-3201 cve CVE-2021-47441 Rebuild_History Non-Buildable kernel-rt-4.18.0-553.22.1.rt7.363.el8_10 commit-author Ido Schimmel <idosch@nvidia.com> commit 332fdf9 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 a421ce0 ("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-1629-5c67-1895-1fdc45c0244e@linaro.org/ [3] https://lore.kernel.org/linux-pm/af9857f2-578e-de3a-e62b-6baff7e69fd4@linaro.org/ CC: Daniel Lezcano <daniel.lezcano@linaro.org> Fixes: a50c1e3 ("mlxsw: core: Implement thermal zone") Fixes: a421ce0 ("mlxsw: core: Extend cooling device with cooling levels") Signed-off-by: Ido Schimmel <idosch@nvidia.com> Tested-by: Vadim Pasternak <vadimp@nvidia.com> Link: https://lore.kernel.org/r/20211012174955.472928-1-idosch@idosch.org Signed-off-by: Jakub Kicinski <kuba@kernel.org> (cherry picked from commit 332fdf9) Signed-off-by: Jonathan Maple <jmaple@ciq.com>
diff --git a/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c b/drivers/net/ethernet/mellanox/mlxsw/core_thermal.c
@@ -24,16 +24,8 @@
 #define MLXSW_THERMAL_ZONE_MAX_NAME	16
 #define MLXSW_THERMAL_TEMP_SCORE_MAX	GENMASK(31, 0)
 #define MLXSW_THERMAL_MAX_STATE	10
+#define MLXSW_THERMAL_MIN_STATE	2
 #define MLXSW_THERMAL_MAX_DUTY	255
-/* Minimum and maximum fan allowed speed in percent: from 20% to 100%. Values
- * MLXSW_THERMAL_MAX_STATE + x, where x is between 2 and 10 are used for
- * setting fan speed dynamic minimum. For example, if value is set to 14 (40%)
- * cooling levels vector will be set to 4, 4, 4, 4, 4, 5, 6, 7, 8, 9, 10 to
- * introduce PWM speed in percent: 40, 40, 40, 40, 40, 50, 60. 70, 80, 90, 100.
- */
-#define MLXSW_THERMAL_SPEED_MIN		(MLXSW_THERMAL_MAX_STATE + 2)
-#define MLXSW_THERMAL_SPEED_MAX		(MLXSW_THERMAL_MAX_STATE * 2)
-#define MLXSW_THERMAL_SPEED_MIN_LEVEL	2		/* 20% */
 
 /* External cooling devices, allowed for binding to mlxsw thermal zones. */
 static char * const mlxsw_thermal_external_allowed_cdev[] = {
@@ -620,49 +612,16 @@ static int mlxsw_thermal_set_cur_state(struct thermal_cooling_device *cdev,
 	struct mlxsw_thermal *thermal = cdev->devdata;
 	struct device *dev = thermal->bus_info->dev;
 	char mfsc_pl[MLXSW_REG_MFSC_LEN];
-	unsigned long cur_state, i;
 	int idx;
-	u8 duty;
 	int err;
 
+	if (state > MLXSW_THERMAL_MAX_STATE)
+		return -EINVAL;
+
 	idx = mlxsw_get_cooling_device_idx(thermal, cdev);
 	if (idx < 0)
 		return idx;
 
-	/* Verify if this request is for changing allowed fan dynamical
-	 * minimum. If it is - update cooling levels accordingly and update
-	 * state, if current state is below the newly requested minimum state.
-	 * For example, if current state is 5, and minimal state is to be
-	 * changed from 4 to 6, thermal->cooling_levels[0 to 5] will be changed
-	 * all from 4 to 6. And state 5 (thermal->cooling_levels[4]) should be
-	 * overwritten.
-	 */
-	if (state >= MLXSW_THERMAL_SPEED_MIN &&
-	    state <= MLXSW_THERMAL_SPEED_MAX) {
-		state -= MLXSW_THERMAL_MAX_STATE;
-		for (i = 0; i <= MLXSW_THERMAL_MAX_STATE; i++)
-			thermal->cooling_levels[i] = max(state, i);
-
-		mlxsw_reg_mfsc_pack(mfsc_pl, idx, 0);
-		err = mlxsw_reg_query(thermal->core, MLXSW_REG(mfsc), mfsc_pl);
-		if (err)
-			return err;
-
-		duty = mlxsw_reg_mfsc_pwm_duty_cycle_get(mfsc_pl);
-		cur_state = mlxsw_duty_to_state(duty);
-
-		/* If current fan state is lower than requested dynamical
-		 * minimum, increase fan speed up to dynamical minimum.
-		 */
-		if (state < cur_state)
-			return 0;
-
-		state = cur_state;
-	}
-
-	if (state > MLXSW_THERMAL_MAX_STATE)
-		return -EINVAL;
-
 	/* Normalize the state to the valid speed range. */
 	state = thermal->cooling_levels[state];
 	mlxsw_reg_mfsc_pack(mfsc_pl, idx, mlxsw_state_to_duty(state));
@@ -963,8 +922,7 @@ int mlxsw_thermal_init(struct mlxsw_core *core,
 
 	/* Initialize cooling levels per PWM state. */
 	for (i = 0; i < MLXSW_THERMAL_MAX_STATE; i++)
-		thermal->cooling_levels[i] = max(MLXSW_THERMAL_SPEED_MIN_LEVEL,
-						 i);
+		thermal->cooling_levels[i] = max(MLXSW_THERMAL_MIN_STATE, i);
 
 	thermal->polling_delay = bus_info->low_frequency ?
 				 MLXSW_THERMAL_SLOW_POLL_INT :
