| Message ID | 20230918-power-uaf-v1-1-73c397178c42@axis.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere, archived |
| Headers | show |
| Series | power: supply: Fix info use-after-free | expand |
Hi Vincent, On Mon, Sep 18, 2023 at 09:33:26AM +0200, Vincent Whitchurch wrote: > power_supply_uevent() which is called to emit a udev event on device > deletion attempts to use the info structure which is device-managed and > has been freed before this point. The use-after-free is triggered since > commit 699fb50d99039 ("drivers: base: Free devm resources when > unregistering a device"). > > Fix this by associating the devm resource with the parent device > instead, similar to recent fixes done in the input subsystem, such as > commit dd613a4e45f8 ("HID: uclogic: Correct devm device reference for > hidinput input_dev"). > > Note that the power supply subsystem allows drivers to register a device > without a parent (with a warning), in this case there is still a risk of > use-after-free since we have no other device to attach the devm to. Thanks for the bug report with a potential fix already included :) I think in case of power-supply this might be enough? diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c index 06e5b6b0e255..d483a81560ab 100644 --- a/drivers/power/supply/power_supply_sysfs.c +++ b/drivers/power/supply/power_supply_sysfs.c @@ -482,6 +482,13 @@ int power_supply_uevent(const struct device *dev, struct kobj_uevent_env *env) if (ret) return ret; + /* + * Kernel generates KOBJ_REMOVE uevent in device removal path, after + * resources have been freed. Exit early to avoid use-after-free. + */ + if (psy->removing) + return 0; + prop_buf = (char *)get_zeroed_page(GFP_KERNEL); if (!prop_buf) return -ENOMEM; That would also cover the no-parent-device part and avoid the device(s) being queried for data at device removal time, which wouldn't work if the device removal happens due to a hot-unplug. -- Sebastian > > ================================================================== > BUG: KASAN: slab-use-after-free in power_supply_battery_info_has_prop (power_supply_core.c:872) > Read of size 4 at addr 0000000062e59028 by task python3/27 > > Call Trace: > power_supply_battery_info_has_prop (power_supply_core.c:872) > power_supply_uevent (power_supply_sysfs.c:504) > dev_uevent (drivers/base/core.c:2590) > kobject_uevent_env (lib/kobject_uevent.c:558) > kobject_uevent (lib/kobject_uevent.c:643) > device_del (drivers/base/core.c:3266 drivers/base/core.c:3831) > device_unregister (drivers/base/core.c:3730 drivers/base/core.c:3854) > power_supply_unregister (power_supply_core.c:1608) > devm_power_supply_release (power_supply_core.c:1515) > release_nodes (drivers/base/devres.c:506) > devres_release_group (drivers/base/devres.c:669) > i2c_device_remove (drivers/i2c/i2c-core-base.c:629) > device_remove (drivers/base/dd.c:570) > device_release_driver_internal (drivers/base/dd.c:1274 drivers/base/dd.c:1295) > device_driver_detach (drivers/base/dd.c:1332) > unbind_store (drivers/base/bus.c:247) > ... > > Allocated by task 27: > devm_kmalloc (drivers/base/devres.c:119 drivers/base/devres.c:829) > power_supply_get_battery_info (include/linux/device.h:316 power_supply_core.c:626) > __power_supply_register (power_supply_core.c:1408) > devm_power_supply_register (power_supply_core.c:1544) > bq256xx_probe (bq256xx_charger.c:1539 bq256xx_charger.c:1727) bq256xx_charger > i2c_device_probe (drivers/i2c/i2c-core-base.c:584) > really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658) > __driver_probe_device (drivers/base/dd.c:800) > device_driver_attach (drivers/base/dd.c:1128) > bind_store (drivers/base/bus.c:273) > ... > > Freed by task 27: > kfree (mm/slab_common.c:1073) > release_nodes (drivers/base/devres.c:503) > devres_release_all (drivers/base/devres.c:536) > device_del (drivers/base/core.c:3829) > device_unregister (drivers/base/core.c:3730 drivers/base/core.c:3854) > power_supply_unregister (power_supply_core.c:1608) > devm_power_supply_release (power_supply_core.c:1515) > release_nodes (drivers/base/devres.c:506) > devres_release_group (drivers/base/devres.c:669) > i2c_device_remove (drivers/i2c/i2c-core-base.c:629) > device_remove (drivers/base/dd.c:570) > device_release_driver_internal (drivers/base/dd.c:1274 drivers/base/dd.c:1295) > device_driver_detach (drivers/base/dd.c:1332) > unbind_store (drivers/base/bus.c:247) > ... > ================================================================== > > Fixes: 27a2195efa8d ("power: supply: core: auto-exposure of simple-battery data") > Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> > --- > drivers/power/supply/power_supply_core.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c > index 0b69fb7bafd8..2863b0a4dfc7 100644 > --- a/drivers/power/supply/power_supply_core.c > +++ b/drivers/power/supply/power_supply_core.c > @@ -573,6 +573,7 @@ EXPORT_SYMBOL_GPL(devm_power_supply_get_by_phandle); > int power_supply_get_battery_info(struct power_supply *psy, > struct power_supply_battery_info **info_out) > { > + struct device *allocdev = psy->dev.parent ?: &psy->dev; > struct power_supply_resistance_temp_table *resist_table; > struct power_supply_battery_info *info; > struct device_node *battery_np = NULL; > @@ -623,7 +624,7 @@ int power_supply_get_battery_info(struct power_supply *psy, > goto out_put_node; > } > > - info = devm_kzalloc(&psy->dev, sizeof(*info), GFP_KERNEL); > + info = devm_kzalloc(allocdev, sizeof(*info), GFP_KERNEL); > if (!info) { > err = -ENOMEM; > goto out_put_node; > @@ -776,7 +777,7 @@ int power_supply_get_battery_info(struct power_supply *psy, > info->ocv_table_size[index] = tab_len; > > table = info->ocv_table[index] = > - devm_kcalloc(&psy->dev, tab_len, sizeof(*table), GFP_KERNEL); > + devm_kcalloc(allocdev, tab_len, sizeof(*table), GFP_KERNEL); > if (!info->ocv_table[index]) { > power_supply_put_battery_info(psy, info); > err = -ENOMEM; > @@ -796,7 +797,7 @@ int power_supply_get_battery_info(struct power_supply *psy, > goto out_ret_pointer; > > info->resist_table_size = len / (2 * sizeof(__be32)); > - resist_table = info->resist_table = devm_kcalloc(&psy->dev, > + resist_table = info->resist_table = devm_kcalloc(allocdev, > info->resist_table_size, > sizeof(*resist_table), > GFP_KERNEL); > @@ -825,17 +826,18 @@ EXPORT_SYMBOL_GPL(power_supply_get_battery_info); > void power_supply_put_battery_info(struct power_supply *psy, > struct power_supply_battery_info *info) > { > + struct device *allocdev = psy->dev.parent ?: &psy->dev; > int i; > > for (i = 0; i < POWER_SUPPLY_OCV_TEMP_MAX; i++) { > if (info->ocv_table[i]) > - devm_kfree(&psy->dev, info->ocv_table[i]); > + devm_kfree(allocdev, info->ocv_table[i]); > } > > if (info->resist_table) > - devm_kfree(&psy->dev, info->resist_table); > + devm_kfree(allocdev, info->resist_table); > > - devm_kfree(&psy->dev, info); > + devm_kfree(allocdev, info); > } > EXPORT_SYMBOL_GPL(power_supply_put_battery_info); > > > --- > base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d > change-id: 20230918-power-uaf-6f7f1b585ec5 > > Best regards, > -- > Vincent Whitchurch <vincent.whitchurch@axis.com> >
On Mon, 2023-09-18 at 17:04 +0200, Sebastian Reichel wrote: > diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c > index 06e5b6b0e255..d483a81560ab 100644 > --- a/drivers/power/supply/power_supply_sysfs.c > +++ b/drivers/power/supply/power_supply_sysfs.c > @@ -482,6 +482,13 @@ int power_supply_uevent(const struct device *dev, struct kobj_uevent_env *env) > if (ret) > return ret; > > > + /* > + * Kernel generates KOBJ_REMOVE uevent in device removal path, after > + * resources have been freed. Exit early to avoid use-after-free. > + */ > + if (psy->removing) > + return 0; > + > prop_buf = (char *)get_zeroed_page(GFP_KERNEL); > if (!prop_buf) > return -ENOMEM; > > That would also cover the no-parent-device part and avoid the > device(s) being queried for data at device removal time, which > wouldn't work if the device removal happens due to a hot-unplug. Works for me. Tested-by: Vincent Whitchurch <vincent.whitchurch@axis.com>
Hi, On Tue, Sep 19, 2023 at 07:33:01AM +0000, Vincent Whitchurch wrote: > On Mon, 2023-09-18 at 17:04 +0200, Sebastian Reichel wrote: > > diff --git a/drivers/power/supply/power_supply_sysfs.c b/drivers/power/supply/power_supply_sysfs.c > > index 06e5b6b0e255..d483a81560ab 100644 > > --- a/drivers/power/supply/power_supply_sysfs.c > > +++ b/drivers/power/supply/power_supply_sysfs.c > > @@ -482,6 +482,13 @@ int power_supply_uevent(const struct device *dev, struct kobj_uevent_env *env) > > if (ret) > > return ret; > > > > > > + /* > > + * Kernel generates KOBJ_REMOVE uevent in device removal path, after > > + * resources have been freed. Exit early to avoid use-after-free. > > + */ > > + if (psy->removing) > > + return 0; > > + > > prop_buf = (char *)get_zeroed_page(GFP_KERNEL); > > if (!prop_buf) > > return -ENOMEM; > > > > That would also cover the no-parent-device part and avoid the > > device(s) being queried for data at device removal time, which > > wouldn't work if the device removal happens due to a hot-unplug. > > Works for me. > > Tested-by: Vincent Whitchurch <vincent.whitchurch@axis.com> Ok, I added it to power-supply's fixes branch as 3dc0bab23dba53f315c9a7b4a679e0a6d46f7c6e. -- Sebastian
diff --git a/drivers/power/supply/power_supply_core.c b/drivers/power/supply/power_supply_core.c index 0b69fb7bafd8..2863b0a4dfc7 100644 --- a/drivers/power/supply/power_supply_core.c +++ b/drivers/power/supply/power_supply_core.c @@ -573,6 +573,7 @@ EXPORT_SYMBOL_GPL(devm_power_supply_get_by_phandle); int power_supply_get_battery_info(struct power_supply *psy, struct power_supply_battery_info **info_out) { + struct device *allocdev = psy->dev.parent ?: &psy->dev; struct power_supply_resistance_temp_table *resist_table; struct power_supply_battery_info *info; struct device_node *battery_np = NULL; @@ -623,7 +624,7 @@ int power_supply_get_battery_info(struct power_supply *psy, goto out_put_node; } - info = devm_kzalloc(&psy->dev, sizeof(*info), GFP_KERNEL); + info = devm_kzalloc(allocdev, sizeof(*info), GFP_KERNEL); if (!info) { err = -ENOMEM; goto out_put_node; @@ -776,7 +777,7 @@ int power_supply_get_battery_info(struct power_supply *psy, info->ocv_table_size[index] = tab_len; table = info->ocv_table[index] = - devm_kcalloc(&psy->dev, tab_len, sizeof(*table), GFP_KERNEL); + devm_kcalloc(allocdev, tab_len, sizeof(*table), GFP_KERNEL); if (!info->ocv_table[index]) { power_supply_put_battery_info(psy, info); err = -ENOMEM; @@ -796,7 +797,7 @@ int power_supply_get_battery_info(struct power_supply *psy, goto out_ret_pointer; info->resist_table_size = len / (2 * sizeof(__be32)); - resist_table = info->resist_table = devm_kcalloc(&psy->dev, + resist_table = info->resist_table = devm_kcalloc(allocdev, info->resist_table_size, sizeof(*resist_table), GFP_KERNEL); @@ -825,17 +826,18 @@ EXPORT_SYMBOL_GPL(power_supply_get_battery_info); void power_supply_put_battery_info(struct power_supply *psy, struct power_supply_battery_info *info) { + struct device *allocdev = psy->dev.parent ?: &psy->dev; int i; for (i = 0; i < POWER_SUPPLY_OCV_TEMP_MAX; i++) { if (info->ocv_table[i]) - devm_kfree(&psy->dev, info->ocv_table[i]); + devm_kfree(allocdev, info->ocv_table[i]); } if (info->resist_table) - devm_kfree(&psy->dev, info->resist_table); + devm_kfree(allocdev, info->resist_table); - devm_kfree(&psy->dev, info); + devm_kfree(allocdev, info); } EXPORT_SYMBOL_GPL(power_supply_put_battery_info);
power_supply_uevent() which is called to emit a udev event on device deletion attempts to use the info structure which is device-managed and has been freed before this point. The use-after-free is triggered since commit 699fb50d99039 ("drivers: base: Free devm resources when unregistering a device"). Fix this by associating the devm resource with the parent device instead, similar to recent fixes done in the input subsystem, such as commit dd613a4e45f8 ("HID: uclogic: Correct devm device reference for hidinput input_dev"). Note that the power supply subsystem allows drivers to register a device without a parent (with a warning), in this case there is still a risk of use-after-free since we have no other device to attach the devm to. ================================================================== BUG: KASAN: slab-use-after-free in power_supply_battery_info_has_prop (power_supply_core.c:872) Read of size 4 at addr 0000000062e59028 by task python3/27 Call Trace: power_supply_battery_info_has_prop (power_supply_core.c:872) power_supply_uevent (power_supply_sysfs.c:504) dev_uevent (drivers/base/core.c:2590) kobject_uevent_env (lib/kobject_uevent.c:558) kobject_uevent (lib/kobject_uevent.c:643) device_del (drivers/base/core.c:3266 drivers/base/core.c:3831) device_unregister (drivers/base/core.c:3730 drivers/base/core.c:3854) power_supply_unregister (power_supply_core.c:1608) devm_power_supply_release (power_supply_core.c:1515) release_nodes (drivers/base/devres.c:506) devres_release_group (drivers/base/devres.c:669) i2c_device_remove (drivers/i2c/i2c-core-base.c:629) device_remove (drivers/base/dd.c:570) device_release_driver_internal (drivers/base/dd.c:1274 drivers/base/dd.c:1295) device_driver_detach (drivers/base/dd.c:1332) unbind_store (drivers/base/bus.c:247) ... Allocated by task 27: devm_kmalloc (drivers/base/devres.c:119 drivers/base/devres.c:829) power_supply_get_battery_info (include/linux/device.h:316 power_supply_core.c:626) __power_supply_register (power_supply_core.c:1408) devm_power_supply_register (power_supply_core.c:1544) bq256xx_probe (bq256xx_charger.c:1539 bq256xx_charger.c:1727) bq256xx_charger i2c_device_probe (drivers/i2c/i2c-core-base.c:584) really_probe (drivers/base/dd.c:579 drivers/base/dd.c:658) __driver_probe_device (drivers/base/dd.c:800) device_driver_attach (drivers/base/dd.c:1128) bind_store (drivers/base/bus.c:273) ... Freed by task 27: kfree (mm/slab_common.c:1073) release_nodes (drivers/base/devres.c:503) devres_release_all (drivers/base/devres.c:536) device_del (drivers/base/core.c:3829) device_unregister (drivers/base/core.c:3730 drivers/base/core.c:3854) power_supply_unregister (power_supply_core.c:1608) devm_power_supply_release (power_supply_core.c:1515) release_nodes (drivers/base/devres.c:506) devres_release_group (drivers/base/devres.c:669) i2c_device_remove (drivers/i2c/i2c-core-base.c:629) device_remove (drivers/base/dd.c:570) device_release_driver_internal (drivers/base/dd.c:1274 drivers/base/dd.c:1295) device_driver_detach (drivers/base/dd.c:1332) unbind_store (drivers/base/bus.c:247) ... ================================================================== Fixes: 27a2195efa8d ("power: supply: core: auto-exposure of simple-battery data") Signed-off-by: Vincent Whitchurch <vincent.whitchurch@axis.com> --- drivers/power/supply/power_supply_core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) --- base-commit: 0bb80ecc33a8fb5a682236443c1e740d5c917d1d change-id: 20230918-power-uaf-6f7f1b585ec5 Best regards,