I noticed a recurring pattern is present in multiple hid devices in the
Linux tree, where the LED controller of a device schedules a work_struct
to interact with the hardware.
The work_struct is embedded in the device structure and thus, is freed
at device removal.
The issue is that a LED worker may be scheduled by a timer concurrently
with device removal, causing the work_struct to be accessed after having
been freed.
I was able to trigger the issue in hid-bigbenff.c and hid-asus.c
where the work_structs may be scheduled by the LED controller
while the device is disconnecting, triggering use-after-frees.
I can attach the reproducer, but it's very simple USB configuration,
using the /dev/raw-gadget interface with some more USB interactions
to manage LEDs configuration and pass checks in asus_kbd_init()
and asus_kbd_get_functions() in case of hid-asus.c.
I triggered the issue by connecting a device and immediately
disconnecting it, so that the remove function runs before the LED one
which remains pending.
I am attaching multiple patches for asus and bigben drivers.
The proposed patches introduce safe wrappers to schedule the workers
safely with several spinlocks checks.
I attach the (partial for brevity) ODEBUG dumps:
```hid-bigbenff.c
[ 37.803135][ T1170] usb 1-1: USB disconnect, device number 2
[ 37.827979][ T1170] ODEBUG: free active (active state 0) object
type: work_struct hint: bigben_worker+0x0/0x860
[ 37.829634][ T1170] WARNING: CPU: 0 PID: 1170 at
lib/debugobjects.c:505 debug_check_no_obj_freed+0x43a/0x630
[ 37.830904][ T1170] Modules linked in:
[ 37.831413][ T1170] CPU: 0 PID: 1170 Comm: kworker/0:3 Not tainted
6.1.0-rc4-dirty #43
[ 37.832465][ T1170] Hardware name: QEMU Standard PC (i440FX + PIIX,
1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 37.833751][ T1170] Workqueue: usb_hub_wq hub_event
[ 37.834409][ T1170] RIP: 0010:debug_check_no_obj_freed+0x43a/0x630
[ 37.835218][ T1170] Code: 48 89 ef e8 28 82 58 ff 49 8b 14 24 4c 8b
45 00 48 c7 c7 40 5f 09 87 48 c7 c6 60 5b 09 87 89 d9 4d 89 f9 31 c0
e8 46 25 ef fe <0f> 0b 4c 8b 64 24 20 48 ba 00 00 00 00 00 fc ff df ff
05 4f 7c 17
[ 37.837667][ T1170] RSP: 0018:ffffc900006fee60 EFLAGS: 00010246
[ 37.838503][ T1170] RAX: 0d2d19ffcded3d00 RBX: 0000000000000000
RCX: ffff888117fc9b00
[ 37.839519][ T1170] RDX: 0000000000000000 RSI: 0000000000000000
RDI: 0000000000000000
[ 37.840570][ T1170] RBP: ffffffff86e88380 R08: ffffffff8130793b
R09: fffff520000dfd85
[ 37.841618][ T1170] R10: fffff520000dfd85 R11: 0000000000000000
R12: ffffffff87095fb8
[ 37.842649][ T1170] R13: ffff888117770ad8 R14: ffff888117770acc
R15: ffffffff852b7420
[ 37.843728][ T1170] FS: 0000000000000000(0000)
GS:ffff8881f6600000(0000) knlGS:0000000000000000
[ 37.844877][ T1170] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 37.845749][ T1170] CR2: 00007f992eaab380 CR3: 000000011834b000
CR4: 00000000001006f0
[ 37.846794][ T1170] Call Trace:
[ 37.847245][ T1170] <TASK>
[ 37.847643][ T1170] slab_free_freelist_hook+0x89/0x160
[ 37.848409][ T1170] ? devres_release_all+0x262/0x350
[ 37.849156][ T1170] __kmem_cache_free+0x71/0x110
[ 37.849829][ T1170] devres_release_all+0x262/0x350
[ 37.850478][ T1170] ? devres_release+0x90/0x90
[ 37.851118][ T1170] device_release_driver_internal+0x5e5/0x8a0
[ 37.851944][ T1170] bus_remove_device+0x2ea/0x400
[ 37.852611][ T1170] device_del+0x64f/0xb40
[ 37.853212][ T1170] ? kill_device+0x150/0x150
[ 37.853831][ T1170] ? print_irqtrace_events+0x1f0/0x1f0
[ 37.854564][ T1170] hid_destroy_device+0x66/0x100
[ 37.855226][ T1170] usbhid_disconnect+0x9a/0xc0
[ 37.855887][ T1170] usb_unbind_interface+0x1e1/0x890
```
``` hid-asus.c
[ 77.409878][ T1169] usb 1-1: USB disconnect, device number 2
[ 77.423606][ T1169] ODEBUG: free active (active state 0) object
type: work_struct hint: asus_kbd_backlight_work+0x0/0x2c0
[ 77.425222][ T1169] WARNING: CPU: 0 PID: 1169 at
lib/debugobjects.c:505 debug_check_no_obj_freed+0x43a/0x630
[ 77.426599][ T1169] Modules linked in:
[ 77.427322][ T1169] CPU: 0 PID: 1169 Comm: kworker/0:3 Not tainted
6.1.0-rc4-dirty #43
[ 77.428404][ T1169] Hardware name: QEMU Standard PC (i440FX + PIIX,
1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
[ 77.429644][ T1169] Workqueue: usb_hub_wq hub_event
[ 77.430296][ T1169] RIP: 0010:debug_check_no_obj_freed+0x43a/0x630
[ 77.431142][ T1169] Code: 48 89 ef e8 28 82 58 ff 49 8b 14 24 4c 8b
45 00 48 c7 c7 40 5f 09 87 48 c7 c6 60 5b 09 87 89 d9 4d 89 f9 31 c0
e8 46 25 ef fe <0f> 0b 4c 8b 64 24 20 48 ba 00 00 00 00 00 fc ff df ff
05 4f 7c 17
[ 77.433691][ T1169] RSP: 0018:ffffc9000069ee60 EFLAGS: 00010246
[ 77.434470][ T1169] RAX: b85d2b40c12d7600 RBX: 0000000000000000
RCX: ffff888117a78000
[ 77.435507][ T1169] RDX: 0000000000000000 RSI: 0000000080000000
RDI: 0000000000000000
[ 77.436521][ T1169] RBP: ffffffff86e88380 R08: ffffffff8130793b
R09: ffffed103ecc4ed6
[ 77.437582][ T1169] R10: ffffed103ecc4ed6 R11: 0000000000000000
R12: ffffffff87095fb8
[ 77.438593][ T1169] R13: ffff88810e348fe0 R14: ffff88810e348fd4
R15: ffffffff852b5780
[ 77.439667][ T1169] FS: 0000000000000000(0000)
GS:ffff8881f6600000(0000) knlGS:0000000000000000
[ 77.440842][ T1169] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 77.441688][ T1169] CR2: 00007ffc05495ff0 CR3: 000000010cdf0000
CR4: 00000000001006f0
[ 77.442720][ T1169] Call Trace:
[ 77.443167][ T1169] <TASK>
[ 77.443555][ T1169] slab_free_freelist_hook+0x89/0x160
[ 77.444302][ T1169] ? devres_release_all+0x262/0x350
[ 77.444990][ T1169] __kmem_cache_free+0x71/0x110
[ 77.445638][ T1169] devres_release_all+0x262/0x350
[ 77.446309][ T1169] ? devres_release+0x90/0x90
[ 77.446978][ T1169] device_release_driver_internal+0x5e5/0x8a0
[ 77.447748][ T1169] bus_remove_device+0x2ea/0x400
[ 77.448421][ T1169] device_del+0x64f/0xb40
[ 77.448976][ T1169] ? kill_device+0x150/0x150
[ 77.449577][ T1169] ? print_irqtrace_events+0x1f0/0x1f0
[ 77.450307][ T1169] hid_destroy_device+0x66/0x100
[ 77.450938][ T1169] usbhid_disconnect+0x9a/0xc0
```
Signed-off-by: Pietro Borrello <[email protected]>
---
Changes in v4:
- Split patches that add spinlock wrt the patches that check scheduling
- Smaller locked regions
- Link to v3: https://lore.kernel.org/r/[email protected]
Changes in v3:
- use spinlocks to prevent workers scheduling
- drop patches on sony & playstation hid drivers
- Link to v2: https://lore.kernel.org/r/[email protected]
Changes in v2:
- dualshock4: Clarify UAF
- dualsense: Clarify UAF
- dualsense: Unregister multicolor led controller
- Link to v1: https://lore.kernel.org/r/[email protected]
---
Pietro Borrello (5):
HID: bigben: use spinlock to protect concurrent accesses
HID: bigben_worker() remove unneeded check on report_field
HID: bigben: use spinlock to safely schedule workers
HID: asus: use spinlock to protect concurrent accesses
HID: asus: use spinlock to safely schedule workers
drivers/hid/hid-asus.c | 37 +++++++++++++++++++++----
drivers/hid/hid-bigbenff.c | 68 +++++++++++++++++++++++++++++++++++++++++-----
2 files changed, 93 insertions(+), 12 deletions(-)
---
base-commit: 2241ab53cbb5cdb08a6b2d4688feb13971058f65
change-id: 20230125-hid-unregister-leds-4cbf67099e1d
Best regards,
--
Pietro Borrello <[email protected]>
bigben driver has a worker that may access data concurrently.
Proct the accesses using a spinlock.
Fixes: 256a90ed9e46 ("HID: hid-bigbenff: driver for BigBen Interactive PS3OFMINIPAD gamepad")
Signed-off-by: Pietro Borrello <[email protected]>
---
drivers/hid/hid-bigbenff.c | 52 ++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 50 insertions(+), 2 deletions(-)
diff --git a/drivers/hid/hid-bigbenff.c b/drivers/hid/hid-bigbenff.c
index e8b16665860d..ed3d2d7bc1dd 100644
--- a/drivers/hid/hid-bigbenff.c
+++ b/drivers/hid/hid-bigbenff.c
@@ -174,6 +174,7 @@ static __u8 pid0902_rdesc_fixed[] = {
struct bigben_device {
struct hid_device *hid;
struct hid_report *report;
+ spinlock_t lock;
bool removed;
u8 led_state; /* LED1 = 1 .. LED4 = 8 */
u8 right_motor_on; /* right motor off/on 0/1 */
@@ -190,12 +191,27 @@ static void bigben_worker(struct work_struct *work)
struct bigben_device *bigben = container_of(work,
struct bigben_device, worker);
struct hid_field *report_field = bigben->report->field[0];
+ bool do_work_led = false;
+ bool do_work_ff = false;
+ u8 *buf;
+ u32 len;
+ unsigned long flags;
if (bigben->removed || !report_field)
return;
+ buf = hid_alloc_report_buf(bigben->report, GFP_KERNEL);
+ if (!buf)
+ return;
+
+ len = hid_report_len(bigben->report);
+
+ /* LED work */
+ spin_lock_irqsave(&bigben->lock, flags);
+
if (bigben->work_led) {
bigben->work_led = false;
+ do_work_led = true;
report_field->value[0] = 0x01; /* 1 = led message */
report_field->value[1] = 0x08; /* reserved value, always 8 */
report_field->value[2] = bigben->led_state;
@@ -204,11 +220,22 @@ static void bigben_worker(struct work_struct *work)
report_field->value[5] = 0x00; /* padding */
report_field->value[6] = 0x00; /* padding */
report_field->value[7] = 0x00; /* padding */
- hid_hw_request(bigben->hid, bigben->report, HID_REQ_SET_REPORT);
+ hid_output_report(bigben->report, buf);
+ }
+
+ spin_unlock_irqrestore(&bigben->lock, flags);
+
+ if (do_work_led) {
+ hid_hw_raw_request(bigben->hid, bigben->report->id, buf, len,
+ bigben->report->type, HID_REQ_SET_REPORT);
}
+ /* FF work */
+ spin_lock_irqsave(&bigben->lock, flags);
+
if (bigben->work_ff) {
bigben->work_ff = false;
+ do_work_ff = true;
report_field->value[0] = 0x02; /* 2 = rumble effect message */
report_field->value[1] = 0x08; /* reserved value, always 8 */
report_field->value[2] = bigben->right_motor_on;
@@ -217,8 +244,17 @@ static void bigben_worker(struct work_struct *work)
report_field->value[5] = 0x00; /* padding */
report_field->value[6] = 0x00; /* padding */
report_field->value[7] = 0x00; /* padding */
- hid_hw_request(bigben->hid, bigben->report, HID_REQ_SET_REPORT);
+ hid_output_report(bigben->report, buf);
+ }
+
+ spin_unlock_irqrestore(&bigben->lock, flags);
+
+ if (do_work_ff) {
+ hid_hw_raw_request(bigben->hid, bigben->report->id, buf, len,
+ bigben->report->type, HID_REQ_SET_REPORT);
}
+
+ kfree(buf);
}
static int hid_bigben_play_effect(struct input_dev *dev, void *data,
@@ -228,6 +264,7 @@ static int hid_bigben_play_effect(struct input_dev *dev, void *data,
struct bigben_device *bigben = hid_get_drvdata(hid);
u8 right_motor_on;
u8 left_motor_force;
+ unsigned long flags;
if (!bigben) {
hid_err(hid, "no device data\n");
@@ -242,9 +279,12 @@ static int hid_bigben_play_effect(struct input_dev *dev, void *data,
if (right_motor_on != bigben->right_motor_on ||
left_motor_force != bigben->left_motor_force) {
+ spin_lock_irqsave(&bigben->lock, flags);
bigben->right_motor_on = right_motor_on;
bigben->left_motor_force = left_motor_force;
bigben->work_ff = true;
+ spin_unlock_irqrestore(&bigben->lock, flags);
+
schedule_work(&bigben->worker);
}
@@ -259,6 +299,7 @@ static void bigben_set_led(struct led_classdev *led,
struct bigben_device *bigben = hid_get_drvdata(hid);
int n;
bool work;
+ unsigned long flags;
if (!bigben) {
hid_err(hid, "no device data\n");
@@ -267,6 +308,7 @@ static void bigben_set_led(struct led_classdev *led,
for (n = 0; n < NUM_LEDS; n++) {
if (led == bigben->leds[n]) {
+ spin_lock_irqsave(&bigben->lock, flags);
if (value == LED_OFF) {
work = (bigben->led_state & BIT(n));
bigben->led_state &= ~BIT(n);
@@ -274,6 +316,7 @@ static void bigben_set_led(struct led_classdev *led,
work = !(bigben->led_state & BIT(n));
bigben->led_state |= BIT(n);
}
+ spin_unlock_irqrestore(&bigben->lock, flags);
if (work) {
bigben->work_led = true;
@@ -307,8 +350,12 @@ static enum led_brightness bigben_get_led(struct led_classdev *led)
static void bigben_remove(struct hid_device *hid)
{
struct bigben_device *bigben = hid_get_drvdata(hid);
+ unsigned long flags;
+ spin_lock_irqsave(&bigben->lock, flags);
bigben->removed = true;
+ spin_unlock_irqrestore(&bigben->lock, flags);
+
cancel_work_sync(&bigben->worker);
hid_hw_stop(hid);
}
@@ -362,6 +409,7 @@ static int bigben_probe(struct hid_device *hid,
set_bit(FF_RUMBLE, hidinput->input->ffbit);
INIT_WORK(&bigben->worker, bigben_worker);
+ spin_lock_init(&bigben->lock);
error = input_ff_create_memless(hidinput->input, NULL,
hid_bigben_play_effect);
--
2.25.1
Use spinlocks to deal with workers introducing a wrapper
bigben_schedule_work(), and several spinlock checks.
Otherwise, bigben_set_led() may schedule bigben->worker after the
structure has been freed, causing a use-after-free.
Fixes: 4eb1b01de5b9 ("HID: hid-bigbenff: fix race condition for scheduled work during removal")
Signed-off-by: Pietro Borrello <[email protected]>
---
drivers/hid/hid-bigbenff.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/hid/hid-bigbenff.c b/drivers/hid/hid-bigbenff.c
index b98c5f31c184..9d6560db762b 100644
--- a/drivers/hid/hid-bigbenff.c
+++ b/drivers/hid/hid-bigbenff.c
@@ -185,6 +185,15 @@ struct bigben_device {
struct work_struct worker;
};
+static inline void bigben_schedule_work(struct bigben_device *bigben)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&bigben->lock, flags);
+ if (!bigben->removed)
+ schedule_work(&bigben->worker);
+ spin_unlock_irqrestore(&bigben->lock, flags);
+}
static void bigben_worker(struct work_struct *work)
{
@@ -197,9 +206,6 @@ static void bigben_worker(struct work_struct *work)
u32 len;
unsigned long flags;
- if (bigben->removed)
- return;
-
buf = hid_alloc_report_buf(bigben->report, GFP_KERNEL);
if (!buf)
return;
@@ -285,7 +291,7 @@ static int hid_bigben_play_effect(struct input_dev *dev, void *data,
bigben->work_ff = true;
spin_unlock_irqrestore(&bigben->lock, flags);
- schedule_work(&bigben->worker);
+ bigben_schedule_work(bigben);
}
return 0;
@@ -320,7 +326,7 @@ static void bigben_set_led(struct led_classdev *led,
if (work) {
bigben->work_led = true;
- schedule_work(&bigben->worker);
+ bigben_schedule_work(bigben);
}
return;
}
@@ -450,7 +456,7 @@ static int bigben_probe(struct hid_device *hid,
bigben->left_motor_force = 0;
bigben->work_led = true;
bigben->work_ff = true;
- schedule_work(&bigben->worker);
+ bigben_schedule_work(bigben);
hid_info(hid, "LED and force feedback support for BigBen gamepad\n");
--
2.25.1
bigben_worker() checks report_field to be non-NULL.
The check has been added in commit
918aa1ef104d ("HID: bigbenff: prevent null pointer dereference")
to prevent a NULL pointer crash.
However, the true root cause was a missing check for output
reports, patched in commit
c7bf714f8755 ("HID: check empty report_list in bigben_probe()"),
where the type-confused report list_entry was overlapping with
a NULL pointer, which was then causing the crash.
Fixes: 918aa1ef104d ("HID: bigbenff: prevent null pointer dereference")
Signed-off-by: Pietro Borrello <[email protected]>
---
drivers/hid/hid-bigbenff.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/hid/hid-bigbenff.c b/drivers/hid/hid-bigbenff.c
index ed3d2d7bc1dd..b98c5f31c184 100644
--- a/drivers/hid/hid-bigbenff.c
+++ b/drivers/hid/hid-bigbenff.c
@@ -197,7 +197,7 @@ static void bigben_worker(struct work_struct *work)
u32 len;
unsigned long flags;
- if (bigben->removed || !report_field)
+ if (bigben->removed)
return;
buf = hid_alloc_report_buf(bigben->report, GFP_KERNEL);
--
2.25.1
asus driver has a worker that may access data concurrently.
Proct the accesses using a spinlock.
Fixes: af22a610bc38 ("HID: asus: support backlight on USB keyboards")
Signed-off-by: Pietro Borrello <[email protected]>
---
drivers/hid/hid-asus.c | 22 +++++++++++++++++++++-
1 file changed, 21 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index f99752b998f3..9f767baf39fb 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -98,6 +98,7 @@ struct asus_kbd_leds {
struct hid_device *hdev;
struct work_struct work;
unsigned int brightness;
+ spinlock_t lock;
bool removed;
};
@@ -495,7 +496,12 @@ static void asus_kbd_backlight_set(struct led_classdev *led_cdev,
{
struct asus_kbd_leds *led = container_of(led_cdev, struct asus_kbd_leds,
cdev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&led->lock, flags);
led->brightness = brightness;
+ spin_unlock_irqrestore(&led->lock, flags);
+
schedule_work(&led->work);
}
@@ -503,8 +509,14 @@ static enum led_brightness asus_kbd_backlight_get(struct led_classdev *led_cdev)
{
struct asus_kbd_leds *led = container_of(led_cdev, struct asus_kbd_leds,
cdev);
+ enum led_brightness brightness;
+ unsigned long flags;
- return led->brightness;
+ spin_lock_irqsave(&led->lock, flags);
+ brightness = led->brightness;
+ spin_unlock_irqrestore(&led->lock, flags);
+
+ return brightness;
}
static void asus_kbd_backlight_work(struct work_struct *work)
@@ -512,11 +524,14 @@ static void asus_kbd_backlight_work(struct work_struct *work)
struct asus_kbd_leds *led = container_of(work, struct asus_kbd_leds, work);
u8 buf[] = { FEATURE_KBD_REPORT_ID, 0xba, 0xc5, 0xc4, 0x00 };
int ret;
+ unsigned long flags;
if (led->removed)
return;
+ spin_lock_irqsave(&led->lock, flags);
buf[4] = led->brightness;
+ spin_unlock_irqrestore(&led->lock, flags);
ret = asus_kbd_set_report(led->hdev, buf, sizeof(buf));
if (ret < 0)
@@ -584,6 +599,7 @@ static int asus_kbd_register_leds(struct hid_device *hdev)
drvdata->kbd_backlight->cdev.brightness_set = asus_kbd_backlight_set;
drvdata->kbd_backlight->cdev.brightness_get = asus_kbd_backlight_get;
INIT_WORK(&drvdata->kbd_backlight->work, asus_kbd_backlight_work);
+ spin_lock_init(&drvdata->kbd_backlight->lock);
ret = devm_led_classdev_register(&hdev->dev, &drvdata->kbd_backlight->cdev);
if (ret < 0) {
@@ -1119,9 +1135,13 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
static void asus_remove(struct hid_device *hdev)
{
struct asus_drvdata *drvdata = hid_get_drvdata(hdev);
+ unsigned long flags;
if (drvdata->kbd_backlight) {
+ spin_lock_irqsave(&drvdata->kbd_backlight->lock, flags);
drvdata->kbd_backlight->removed = true;
+ spin_unlock_irqrestore(&drvdata->kbd_backlight->lock, flags);
+
cancel_work_sync(&drvdata->kbd_backlight->work);
}
--
2.25.1
Use spinlocks to deal with workers introducing a wrapper
asus_schedule_work(), and several spinlock checks.
Otherwise, asus_kbd_backlight_set() may schedule led->work after the
structure has been freed, causing a use-after-free.
Fixes: af22a610bc38 ("HID: asus: support backlight on USB keyboards")
Signed-off-by: Pietro Borrello <[email protected]>
---
drivers/hid/hid-asus.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index 9f767baf39fb..d1094bb1aa42 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -491,6 +491,16 @@ static int rog_nkey_led_init(struct hid_device *hdev)
return ret;
}
+static void asus_schedule_work(struct asus_kbd_leds *led)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&led->lock, flags);
+ if (!led->removed)
+ schedule_work(&led->work);
+ spin_unlock_irqrestore(&led->lock, flags);
+}
+
static void asus_kbd_backlight_set(struct led_classdev *led_cdev,
enum led_brightness brightness)
{
@@ -502,7 +512,7 @@ static void asus_kbd_backlight_set(struct led_classdev *led_cdev,
led->brightness = brightness;
spin_unlock_irqrestore(&led->lock, flags);
- schedule_work(&led->work);
+ asus_schedule_work(led);
}
static enum led_brightness asus_kbd_backlight_get(struct led_classdev *led_cdev)
@@ -526,9 +536,6 @@ static void asus_kbd_backlight_work(struct work_struct *work)
int ret;
unsigned long flags;
- if (led->removed)
- return;
-
spin_lock_irqsave(&led->lock, flags);
buf[4] = led->brightness;
spin_unlock_irqrestore(&led->lock, flags);
--
2.25.1
On Sun, 12 Feb 2023 18:59:58 +0000, Pietro Borrello wrote:
> I noticed a recurring pattern is present in multiple hid devices in the
> Linux tree, where the LED controller of a device schedules a work_struct
> to interact with the hardware.
> The work_struct is embedded in the device structure and thus, is freed
> at device removal.
>
> The issue is that a LED worker may be scheduled by a timer concurrently
> with device removal, causing the work_struct to be accessed after having
> been freed.
> I was able to trigger the issue in hid-bigbenff.c and hid-asus.c
> where the work_structs may be scheduled by the LED controller
> while the device is disconnecting, triggering use-after-frees.
> I can attach the reproducer, but it's very simple USB configuration,
> using the /dev/raw-gadget interface with some more USB interactions
> to manage LEDs configuration and pass checks in asus_kbd_init()
> and asus_kbd_get_functions() in case of hid-asus.c.
> I triggered the issue by connecting a device and immediately
> disconnecting it, so that the remove function runs before the LED one
> which remains pending.
>
> [...]
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git (for-6.3/asus), thanks!
[4/5] HID: asus: use spinlock to protect concurrent accesses
https://git.kernel.org/hid/hid/c/315c537068a1
[5/5] HID: asus: use spinlock to safely schedule workers
https://git.kernel.org/hid/hid/c/4ab3a086d10e
Cheers,
--
Benjamin Tissoires <[email protected]>
On Feb 12 2023, Pietro Borrello wrote:
> I noticed a recurring pattern is present in multiple hid devices in the
> Linux tree, where the LED controller of a device schedules a work_struct
> to interact with the hardware.
> The work_struct is embedded in the device structure and thus, is freed
> at device removal.
>
> The issue is that a LED worker may be scheduled by a timer concurrently
> with device removal, causing the work_struct to be accessed after having
> been freed.
> I was able to trigger the issue in hid-bigbenff.c and hid-asus.c
> where the work_structs may be scheduled by the LED controller
> while the device is disconnecting, triggering use-after-frees.
> I can attach the reproducer, but it's very simple USB configuration,
> using the /dev/raw-gadget interface with some more USB interactions
> to manage LEDs configuration and pass checks in asus_kbd_init()
> and asus_kbd_get_functions() in case of hid-asus.c.
> I triggered the issue by connecting a device and immediately
> disconnecting it, so that the remove function runs before the LED one
> which remains pending.
>
> I am attaching multiple patches for asus and bigben drivers.
> The proposed patches introduce safe wrappers to schedule the workers
> safely with several spinlocks checks.
>
> I attach the (partial for brevity) ODEBUG dumps:
>
> ```hid-bigbenff.c
> [ 37.803135][ T1170] usb 1-1: USB disconnect, device number 2
> [ 37.827979][ T1170] ODEBUG: free active (active state 0) object
> type: work_struct hint: bigben_worker+0x0/0x860
> [ 37.829634][ T1170] WARNING: CPU: 0 PID: 1170 at
> lib/debugobjects.c:505 debug_check_no_obj_freed+0x43a/0x630
> [ 37.830904][ T1170] Modules linked in:
> [ 37.831413][ T1170] CPU: 0 PID: 1170 Comm: kworker/0:3 Not tainted
> 6.1.0-rc4-dirty #43
> [ 37.832465][ T1170] Hardware name: QEMU Standard PC (i440FX + PIIX,
> 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> [ 37.833751][ T1170] Workqueue: usb_hub_wq hub_event
> [ 37.834409][ T1170] RIP: 0010:debug_check_no_obj_freed+0x43a/0x630
> [ 37.835218][ T1170] Code: 48 89 ef e8 28 82 58 ff 49 8b 14 24 4c 8b
> 45 00 48 c7 c7 40 5f 09 87 48 c7 c6 60 5b 09 87 89 d9 4d 89 f9 31 c0
> e8 46 25 ef fe <0f> 0b 4c 8b 64 24 20 48 ba 00 00 00 00 00 fc ff df ff
> 05 4f 7c 17
> [ 37.837667][ T1170] RSP: 0018:ffffc900006fee60 EFLAGS: 00010246
> [ 37.838503][ T1170] RAX: 0d2d19ffcded3d00 RBX: 0000000000000000
> RCX: ffff888117fc9b00
> [ 37.839519][ T1170] RDX: 0000000000000000 RSI: 0000000000000000
> RDI: 0000000000000000
> [ 37.840570][ T1170] RBP: ffffffff86e88380 R08: ffffffff8130793b
> R09: fffff520000dfd85
> [ 37.841618][ T1170] R10: fffff520000dfd85 R11: 0000000000000000
> R12: ffffffff87095fb8
> [ 37.842649][ T1170] R13: ffff888117770ad8 R14: ffff888117770acc
> R15: ffffffff852b7420
> [ 37.843728][ T1170] FS: 0000000000000000(0000)
> GS:ffff8881f6600000(0000) knlGS:0000000000000000
> [ 37.844877][ T1170] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 37.845749][ T1170] CR2: 00007f992eaab380 CR3: 000000011834b000
> CR4: 00000000001006f0
> [ 37.846794][ T1170] Call Trace:
> [ 37.847245][ T1170] <TASK>
> [ 37.847643][ T1170] slab_free_freelist_hook+0x89/0x160
> [ 37.848409][ T1170] ? devres_release_all+0x262/0x350
> [ 37.849156][ T1170] __kmem_cache_free+0x71/0x110
> [ 37.849829][ T1170] devres_release_all+0x262/0x350
> [ 37.850478][ T1170] ? devres_release+0x90/0x90
> [ 37.851118][ T1170] device_release_driver_internal+0x5e5/0x8a0
> [ 37.851944][ T1170] bus_remove_device+0x2ea/0x400
> [ 37.852611][ T1170] device_del+0x64f/0xb40
> [ 37.853212][ T1170] ? kill_device+0x150/0x150
> [ 37.853831][ T1170] ? print_irqtrace_events+0x1f0/0x1f0
> [ 37.854564][ T1170] hid_destroy_device+0x66/0x100
> [ 37.855226][ T1170] usbhid_disconnect+0x9a/0xc0
> [ 37.855887][ T1170] usb_unbind_interface+0x1e1/0x890
> ```
>
> ``` hid-asus.c
> [ 77.409878][ T1169] usb 1-1: USB disconnect, device number 2
> [ 77.423606][ T1169] ODEBUG: free active (active state 0) object
> type: work_struct hint: asus_kbd_backlight_work+0x0/0x2c0
> [ 77.425222][ T1169] WARNING: CPU: 0 PID: 1169 at
> lib/debugobjects.c:505 debug_check_no_obj_freed+0x43a/0x630
> [ 77.426599][ T1169] Modules linked in:
> [ 77.427322][ T1169] CPU: 0 PID: 1169 Comm: kworker/0:3 Not tainted
> 6.1.0-rc4-dirty #43
> [ 77.428404][ T1169] Hardware name: QEMU Standard PC (i440FX + PIIX,
> 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
> [ 77.429644][ T1169] Workqueue: usb_hub_wq hub_event
> [ 77.430296][ T1169] RIP: 0010:debug_check_no_obj_freed+0x43a/0x630
> [ 77.431142][ T1169] Code: 48 89 ef e8 28 82 58 ff 49 8b 14 24 4c 8b
> 45 00 48 c7 c7 40 5f 09 87 48 c7 c6 60 5b 09 87 89 d9 4d 89 f9 31 c0
> e8 46 25 ef fe <0f> 0b 4c 8b 64 24 20 48 ba 00 00 00 00 00 fc ff df ff
> 05 4f 7c 17
> [ 77.433691][ T1169] RSP: 0018:ffffc9000069ee60 EFLAGS: 00010246
> [ 77.434470][ T1169] RAX: b85d2b40c12d7600 RBX: 0000000000000000
> RCX: ffff888117a78000
> [ 77.435507][ T1169] RDX: 0000000000000000 RSI: 0000000080000000
> RDI: 0000000000000000
> [ 77.436521][ T1169] RBP: ffffffff86e88380 R08: ffffffff8130793b
> R09: ffffed103ecc4ed6
> [ 77.437582][ T1169] R10: ffffed103ecc4ed6 R11: 0000000000000000
> R12: ffffffff87095fb8
> [ 77.438593][ T1169] R13: ffff88810e348fe0 R14: ffff88810e348fd4
> R15: ffffffff852b5780
> [ 77.439667][ T1169] FS: 0000000000000000(0000)
> GS:ffff8881f6600000(0000) knlGS:0000000000000000
> [ 77.440842][ T1169] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 77.441688][ T1169] CR2: 00007ffc05495ff0 CR3: 000000010cdf0000
> CR4: 00000000001006f0
> [ 77.442720][ T1169] Call Trace:
> [ 77.443167][ T1169] <TASK>
> [ 77.443555][ T1169] slab_free_freelist_hook+0x89/0x160
> [ 77.444302][ T1169] ? devres_release_all+0x262/0x350
> [ 77.444990][ T1169] __kmem_cache_free+0x71/0x110
> [ 77.445638][ T1169] devres_release_all+0x262/0x350
> [ 77.446309][ T1169] ? devres_release+0x90/0x90
> [ 77.446978][ T1169] device_release_driver_internal+0x5e5/0x8a0
> [ 77.447748][ T1169] bus_remove_device+0x2ea/0x400
> [ 77.448421][ T1169] device_del+0x64f/0xb40
> [ 77.448976][ T1169] ? kill_device+0x150/0x150
> [ 77.449577][ T1169] ? print_irqtrace_events+0x1f0/0x1f0
> [ 77.450307][ T1169] hid_destroy_device+0x66/0x100
> [ 77.450938][ T1169] usbhid_disconnect+0x9a/0xc0
> ```
>
> Signed-off-by: Pietro Borrello <[email protected]>
> ---
> Changes in v4:
> - Split patches that add spinlock wrt the patches that check scheduling
> - Smaller locked regions
> - Link to v3: https://lore.kernel.org/r/[email protected]
>
> Changes in v3:
> - use spinlocks to prevent workers scheduling
> - drop patches on sony & playstation hid drivers
> - Link to v2: https://lore.kernel.org/r/[email protected]
>
> Changes in v2:
> - dualshock4: Clarify UAF
> - dualsense: Clarify UAF
> - dualsense: Unregister multicolor led controller
> - Link to v1: https://lore.kernel.org/r/[email protected]
>
> ---
> Pietro Borrello (5):
> HID: bigben: use spinlock to protect concurrent accesses
> HID: bigben_worker() remove unneeded check on report_field
> HID: bigben: use spinlock to safely schedule workers
> HID: asus: use spinlock to protect concurrent accesses
> HID: asus: use spinlock to safely schedule workers
>
> drivers/hid/hid-asus.c | 37 +++++++++++++++++++++----
> drivers/hid/hid-bigbenff.c | 68 +++++++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 93 insertions(+), 12 deletions(-)
And patches 1-3 applied to hid/hid.git branch for-6.3/bigben
Cheers,
Benjamin
> ---
> base-commit: 2241ab53cbb5cdb08a6b2d4688feb13971058f65
> change-id: 20230125-hid-unregister-leds-4cbf67099e1d
>
> Best regards,
> --
> Pietro Borrello <[email protected]>
>