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[130.37.198.127]) by smtp.gmail.com with ESMTPSA id jy12-20020a170907762c00b008784e808553sm555707ejc.6.2023.01.25.16.25.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Jan 2023 16:25:15 -0800 (PST) From: Pietro Borrello Subject: [PATCH 0/5] HID: manually unregister leds on device removal to prevent UAFs Date: Thu, 26 Jan 2023 00:24:53 +0000 Message-Id: <20230125-hid-unregister-leds-v1-0-9a5192dcef16@diag.uniroma1.it> MIME-Version: 1.0 X-B4-Tracking: v=1; b=H4sIAFXI0WMC/x2NSwrDMAwFrxK0rsB2PyG9SsnCHyUWpG6RklIIu XvtLod5w9tBSZgU7t0OQh9WfpUK9tRBzL7MhJwqgzPubKy7YuaEWxGaWVcSXCgpXmKYbr0ZBrIJ ahm8EgbxJebWPn2bNvEWmvj7v3uMx/EDqjNKDX4AAAA= To: Jiri Kosina , Benjamin Tissoires , Hanno Zulla , Carlo Caione , Pavel Machek , Lee Jones , Roderick Colenbrander , Sven Eckelmann Cc: linux-leds@vger.kernel.org, Cristiano Giuffrida , "Bos, H.J." , Jakob Koschel , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Jiri Kosina , Roderick Colenbrander , Pietro Borrello X-Mailer: b4 0.11.1 X-Developer-Signature: v=1; a=ed25519-sha256; t=1674692715; l=8938; i=borrello@diag.uniroma1.it; s=20221223; h=from:subject:message-id; bh=QdIkage8duwd9pwha6zu89n0T8tDTVZRBDxoP9kF9Mw=; b=fXzHwN750DnttJAeCO91BYVF2+9g4c/zKjp62LHyu93bNaic87TmNnvH3RVlkdCZaqknn5MIW1FG 2n8lM66QAOCDnfCOIAR8TSfyFf0ngp502PN2XMF+eqbMF1H9YGg2 X-Developer-Key: i=borrello@diag.uniroma1.it; a=ed25519; pk=4xRQbiJKehl7dFvrG33o2HpveMrwQiUPKtIlObzKmdY= Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org 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. More drivers have the same pattern (hid-lg-g15.c, hid-playstation.c, hid-sony.c) but I wasn't able to properly pass the right descriptors to trigger the led configurations needed to trigger the workers. Some other drivers manually unregister at removal (hid-corsair.c, hid-gt683r.c, hid-lenovo.c) since they do not use the managed interface, which is safe, to my understanding. Also, a similar pattern is present with callbacks which schedule a worker originating from input_ff_create_memless() (e.g., in hid-bigbenff.c) but in these cases, I wasn't able to trigger the race condition with the event handling to schedule the worker during device removal. However, I have no experience with the USB protocol and I'm not able to say that they cannot be triggered. I am currently wondering if this is due to some emulation of the /dev/raw-gadget interface or if it's effectively an issue with how each device manages resource removal. But I wonder why syzkaller didn't find any crash while fuzzing the interface with upstream-usb.config, as they seem pretty straightforward to trigger. Configuring the kernel with CONFIG_DEBUG_OBJECTS, it emits a warning in debug_check_no_obj_freed, which makes it clear that device removal is freeing resources in use. KASAN detects them as use-after-free. I am attaching multiple patches for all the drivers I suspect the bug is present. The proposed patches unregister the LED controllers before removing the device itself. 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] [ 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] [ 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 ``` To: Jiri Kosina To: Benjamin Tissoires To: Hanno Zulla To: Carlo Caione To: Pavel Machek To: Lee Jones To: Roderick Colenbrander To: Sven Eckelmann Cc: linux-leds@vger.kernel.org Cc: Cristiano Giuffrida Cc: "Bos, H.J." Cc: Jakob Koschel Cc: linux-input@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Jiri Kosina Cc: Roderick Colenbrander Signed-off-by: Pietro Borrello --- Pietro Borrello (5): HID: bigben_remove: manually unregister leds HID: asus_remove: manually unregister led HID: dualsense_remove: manually unregister leds HID: dualshock4_remove: manually unregister leds HID: sony_remove: manually unregister leds drivers/hid/hid-asus.c | 1 + drivers/hid/hid-bigbenff.c | 5 +++++ drivers/hid/hid-playstation.c | 8 ++++++++ drivers/hid/hid-sony.c | 8 ++++++++ 4 files changed, 22 insertions(+) --- base-commit: 2241ab53cbb5cdb08a6b2d4688feb13971058f65 change-id: 20230125-hid-unregister-leds-4cbf67099e1d Best regards,