CVE-2025-40016

Description

In the Linux kernel, the following vulnerability has been resolved:media: uvcvideo: Mark invalid entities with id UVC_INVALID_ENTITY_IDPer UVC 1.1+ specification 3.7.2, units and terminals must have a non-zerounique ID.Each Unit and Terminal within the video function is assigned a uniqueidentification number, the Unit ID (UID) or Terminal ID (TID), contained inthe bUnitID or bTerminalID field of the descriptor. The value 0x00 isreserved for undefined ID,If we add a new entity with id 0 or a duplicated ID, it will be markedas UVC_INVALID_ENTITY_ID.In a previous attempt commit 3dd075fe8ebb (media: uvcvideo: Requireentities 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 luckythis time.This also prevents some syzkaller reproducers from triggering warnings dueto a chain of entities referring to themselves. In one particular case, anOutput Unit is connected to an Input Unit, both with the same ID of 1. Butwhen looking up for the source ID of the Output Unit, that same entity isfound instead of the input entity, which leads to such warnings.In another case, a backward chain was considered finished as the source IDwas 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 (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] [ 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+0x1---truncated---

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234