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Message-ID: <2025102004-CVE-2025-40016-bfe1@gregkh>
Date: Mon, 20 Oct 2025 17:29:07 +0200
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-cve-announce@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...nel.org>
Subject: CVE-2025-40016: media: uvcvideo: Mark invalid entities with id UVC_INVALID_ENTITY_ID
From: Greg Kroah-Hartman <gregkh@...nel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
media: uvcvideo: Mark invalid entities with id UVC_INVALID_ENTITY_ID
Per UVC 1.1+ specification 3.7.2, units and terminals must have a non-zero
unique ID.
```
Each Unit and Terminal within the video function is assigned a unique
identification number, the Unit ID (UID) or Terminal ID (TID), contained in
the bUnitID or bTerminalID field of the descriptor. The value 0x00 is
reserved for undefined ID,
```
If we add a new entity with id 0 or a duplicated ID, it will be marked
as UVC_INVALID_ENTITY_ID.
In a previous attempt commit 3dd075fe8ebb ("media: uvcvideo: Require
entities to have a non-zero unique ID"), we ignored all the invalid units,
this broke a lot of non-compatible cameras. Hopefully we are more lucky
this time.
This also prevents some syzkaller reproducers from triggering warnings due
to a chain of entities referring to themselves. In one particular case, an
Output Unit is connected to an Input Unit, both with the same ID of 1. But
when looking up for the source ID of the Output Unit, that same entity is
found instead of the input entity, which leads to such warnings.
In another case, a backward chain was considered finished as the source ID
was 0. Later on, that entity was found, but its pads were not valid.
Here is a sample stack trace for one of those cases.
[ 20.650953] usb 1-1: new high-speed USB device number 2 using dummy_hcd
[ 20.830206] usb 1-1: Using ep0 maxpacket: 8
[ 20.833501] usb 1-1: config 0 descriptor??
[ 21.038518] usb 1-1: string descriptor 0 read error: -71
[ 21.038893] usb 1-1: Found UVC 0.00 device <unnamed> (2833:0201)
[ 21.039299] uvcvideo 1-1:0.0: Entity type for entity Output 1 was not initialized!
[ 21.041583] uvcvideo 1-1:0.0: Entity type for entity Input 1 was not initialized!
[ 21.042218] ------------[ cut here ]------------
[ 21.042536] WARNING: CPU: 0 PID: 9 at drivers/media/mc/mc-entity.c:1147 media_create_pad_link+0x2c4/0x2e0
[ 21.043195] Modules linked in:
[ 21.043535] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Not tainted 6.11.0-rc7-00030-g3480e43aeccf #444
[ 21.044101] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
[ 21.044639] Workqueue: usb_hub_wq hub_event
[ 21.045100] RIP: 0010:media_create_pad_link+0x2c4/0x2e0
[ 21.045508] Code: fe e8 20 01 00 00 b8 f4 ff ff ff 48 83 c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 cc cc cc cc 0f 0b eb e9 0f 0b eb 0a 0f 0b eb 06 <0f> 0b eb 02 0f 0b b8 ea ff ff ff eb d4 66 2e 0f 1f 84 00 00 00 00
[ 21.046801] RSP: 0018:ffffc9000004b318 EFLAGS: 00010246
[ 21.047227] RAX: ffff888004e5d458 RBX: 0000000000000000 RCX: ffffffff818fccf1
[ 21.047719] RDX: 000000000000007b RSI: 0000000000000000 RDI: ffff888004313290
[ 21.048241] RBP: ffff888004313290 R08: 0001ffffffffffff R09: 0000000000000000
[ 21.048701] R10: 0000000000000013 R11: 0001888004313290 R12: 0000000000000003
[ 21.049138] R13: ffff888004313080 R14: ffff888004313080 R15: 0000000000000000
[ 21.049648] FS: 0000000000000000(0000) GS:ffff88803ec00000(0000) knlGS:0000000000000000
[ 21.050271] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 21.050688] CR2: 0000592cc27635b0 CR3: 000000000431c000 CR4: 0000000000750ef0
[ 21.051136] PKRU: 55555554
[ 21.051331] Call Trace:
[ 21.051480] <TASK>
[ 21.051611] ? __warn+0xc4/0x210
[ 21.051861] ? media_create_pad_link+0x2c4/0x2e0
[ 21.052252] ? report_bug+0x11b/0x1a0
[ 21.052540] ? trace_hardirqs_on+0x31/0x40
[ 21.052901] ? handle_bug+0x3d/0x70
[ 21.053197] ? exc_invalid_op+0x1a/0x50
[ 21.053511] ? asm_exc_invalid_op+0x1a/0x20
[ 21.053924] ? media_create_pad_link+0x91/0x2e0
[ 21.054364] ? media_create_pad_link+0x2c4/0x2e0
[ 21.054834] ? media_create_pad_link+0x91/0x2e0
[ 21.055131] ? _raw_spin_unlock+0x1e/0x40
[ 21.055441] ? __v4l2_device_register_subdev+0x202/0x210
[ 21.055837] uvc_mc_register_entities+0x358/0x400
[ 21.056144] uvc_register_chains+0x1fd/0x290
[ 21.056413] uvc_probe+0x380e/0x3dc0
[ 21.056676] ? __lock_acquire+0x5aa/0x26e0
[ 21.056946] ? find_held_lock+0x33/0xa0
[ 21.057196] ? kernfs_activate+0x70/0x80
[ 21.057533] ? usb_match_dynamic_id+0x1b/0x70
[ 21.057811] ? find_held_lock+0x33/0xa0
[ 21.058047] ? usb_match_dynamic_id+0x55/0x70
[ 21.058330] ? lock_release+0x124/0x260
[ 21.058657] ? usb_match_one_id_intf+0xa2/0x100
[ 21.058997] usb_probe_interface+0x1ba/0x330
[ 21.059399] really_probe+0x1ba/0x4c0
[ 21.059662] __driver_probe_device+0xb2/0x180
[ 21.059944] driver_probe_device+0x5a/0x100
[ 21.060170] __device_attach_driver+0xe9/0x160
[ 21.060427] ? __pfx___device_attach_driver+0x10/0x10
[ 21.060872] bus_for_each_drv+0xa9/0x100
[ 21.061312] __device_attach+0xed/0x190
[ 21.061812] device_initial_probe+0xe/0x20
[ 21.062229] bus_probe_device+0x4d/0xd0
[ 21.062590] device_add+0x308/0x590
[ 21.062912] usb_set_configuration+0x7b6/0xaf0
[ 21.063403] usb_generic_driver_probe+0x36/0x80
[ 21.063714] usb_probe_device+0x7b/0x130
[ 21.063936] really_probe+0x1ba/0x4c0
[ 21.064111] __driver_probe_device+0xb2/0x180
[ 21.064577] driver_probe_device+0x5a/0x100
[ 21.065019] __device_attach_driver+0xe9/0x160
[ 21.065403] ? __pfx___device_attach_driver+0x10/0x10
[ 21.065820] bus_for_each_drv+0xa9/0x100
[ 21.066094] __device_attach+0xed/0x190
[ 21.066535] device_initial_probe+0xe/0x20
[ 21.066992] bus_probe_device+0x4d/0xd0
[ 21.067250] device_add+0x308/0x590
[ 21.067501] usb_new_device+0x347/0x610
[ 21.067817] hub_event+0x156b/0x1e30
[ 21.068060] ? process_scheduled_works+0x48b/0xaf0
[ 21.068337] process_scheduled_works+0x5a3/0xaf0
[ 21.068668] worker_thread+0x3cf/0x560
[ 21.068932] ? kthread+0x109/0x1b0
[ 21.069133] kthread+0x197/0x1b0
[ 21.069343] ? __pfx_worker_thread+0x10/0x10
[ 21.069598] ? __pfx_kthread+0x10/0x10
[ 21.069908] ret_from_fork+0x32/0x40
[ 21.070169] ? __pfx_kthread+0x10/0x10
[ 21.070424] ret_from_fork_asm+0x1a/0x30
[ 21.070737] </TASK>
The Linux kernel CVE team has assigned CVE-2025-40016 to this issue.
Affected and fixed versions
===========================
Issue introduced in 5.7 with commit a3fbc2e6bb05a3b1ea341cd29dea09b4a033727b and fixed in 6.6.110 with commit f617d515d66c05e9aebc787a8fe48b7163fc7b70
Issue introduced in 5.7 with commit a3fbc2e6bb05a3b1ea341cd29dea09b4a033727b and fixed in 6.12.51 with commit 000b2a6bed7f30e0aadfb19bce9af6458d879304
Issue introduced in 5.7 with commit a3fbc2e6bb05a3b1ea341cd29dea09b4a033727b and fixed in 6.16.11 with commit 15c0e136bd8cd70a1136a11c7876d6aae0eef8c8
Issue introduced in 5.7 with commit a3fbc2e6bb05a3b1ea341cd29dea09b4a033727b and fixed in 6.17.1 with commit 0f140cede24334b3ee55e3e1127071266cbb8287
Issue introduced in 5.7 with commit a3fbc2e6bb05a3b1ea341cd29dea09b4a033727b and fixed in 6.18-rc1 with commit 0e2ee70291e64a30fe36960c85294726d34a103e
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2025-40016
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
drivers/media/usb/uvc/uvc_driver.c
drivers/media/usb/uvc/uvcvideo.h
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/f617d515d66c05e9aebc787a8fe48b7163fc7b70
https://git.kernel.org/stable/c/000b2a6bed7f30e0aadfb19bce9af6458d879304
https://git.kernel.org/stable/c/15c0e136bd8cd70a1136a11c7876d6aae0eef8c8
https://git.kernel.org/stable/c/0f140cede24334b3ee55e3e1127071266cbb8287
https://git.kernel.org/stable/c/0e2ee70291e64a30fe36960c85294726d34a103e
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