| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <CANiDSCvJjqczwLRH7TNqO7mocPfJeFeFVbKErXsDNX-qj1NwDA@mail.gmail.com>
Date: Mon, 8 Sep 2025 12:35:27 +0200
From: Ricardo Ribalda <ribalda@...omium.org>
To: Laurent Pinchart <laurent.pinchart@...asonboard.com>
Cc: Tomasz Sikora <sikora.tomus@...il.com>,
Thadeu Lima de Souza Cascardo <cascardo@...lia.com>, Hans de Goede <hansg@...nel.org>,
Mauro Carvalho Chehab <mchehab@...nel.org>, Hans Verkuil <hverkuil@...nel.org>,
Mauro Carvalho Chehab <mchehab+huawei@...nel.org>, linux-media@...r.kernel.org,
linux-kernel@...r.kernel.org, stable@...r.kernel.org,
syzbot+0584f746fde3d52b4675@...kaller.appspotmail.com,
syzbot+dd320d114deb3f5bb79b@...kaller.appspotmail.com
Subject: Re: [PATCH] media: uvcvideo: Mark invalid entities with id UVC_INVALID_ENTITY_ID
On Mon, 8 Sept 2025 at 12:33, Laurent Pinchart
<laurent.pinchart@...asonboard.com> wrote:
>
> Hello Ricardo,
>
> Thank you for the patch.
>
> On Wed, Aug 20, 2025 at 04:08:16PM +0000, Ricardo Ribalda wrote:
> > From: Thadeu Lima de Souza Cascardo <cascardo@...lia.com>
> >
> > 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>
> >
> > Cc: stable@...r.kernel.org
> > Reported-by: syzbot+0584f746fde3d52b4675@...kaller.appspotmail.com
> > Closes: https://syzkaller.appspot.com/bug?extid=0584f746fde3d52b4675
> > Reported-by: syzbot+dd320d114deb3f5bb79b@...kaller.appspotmail.com
> > Closes: https://syzkaller.appspot.com/bug?extid=dd320d114deb3f5bb79b
> > Fixes: a3fbc2e6bb05 ("media: mc-entity.c: use WARN_ON, validate link pads")
> > Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@...lia.com>
> > Co-developed-by: Ricardo Ribalda <ribalda@...omium.org>
> > Signed-off-by: Ricardo Ribalda <ribalda@...omium.org>
> > ---
> > This is a new attempt to land a Thadeu's patch, but being a bit more
> > benevolent on the non-compliant cameras.
> >
> > I have kept most of Thadeu's code, but instead of returning an error
> > when trying to allocate an invalid entity, I replace its id with a
> > special ID.
> >
> > Thadeu can you validate this new version?
> >
> > Tomasz can you also check this patch with your non compliant camera?
> >
> > Thanks!
> > ---
> > drivers/media/usb/uvc/uvc_driver.c | 73 ++++++++++++++++++++++++--------------
> > drivers/media/usb/uvc/uvcvideo.h | 2 ++
> > 2 files changed, 48 insertions(+), 27 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c
> > index 775bede0d93d9b3e5391914aa395326d3de6a3b1..46923cd85f0b6790f01ae6b393571ca7660900f7 100644
> > --- a/drivers/media/usb/uvc/uvc_driver.c
> > +++ b/drivers/media/usb/uvc/uvc_driver.c
> > @@ -137,6 +137,9 @@ struct uvc_entity *uvc_entity_by_id(struct uvc_device *dev, int id)
> > {
> > struct uvc_entity *entity;
> >
> > + if (id == UVC_INVALID_ENTITY_ID)
> > + return NULL;
> > +
> > list_for_each_entry(entity, &dev->entities, list) {
> > if (entity->id == id)
> > return entity;
> > @@ -795,14 +798,27 @@ static const u8 uvc_media_transport_input_guid[16] =
> > UVC_GUID_UVC_MEDIA_TRANSPORT_INPUT;
> > static const u8 uvc_processing_guid[16] = UVC_GUID_UVC_PROCESSING;
> >
> > -static struct uvc_entity *uvc_alloc_entity(u16 type, u16 id,
> > - unsigned int num_pads, unsigned int extra_size)
> > +static struct uvc_entity *uvc_alloc_new_entity(struct uvc_device *dev, u16 type,
> > + u16 id, unsigned int num_pads,
> > + unsigned int extra_size)
> > {
> > struct uvc_entity *entity;
> > unsigned int num_inputs;
> > unsigned int size;
> > unsigned int i;
> >
> > + /* Per UVC 1.1+ spec 3.7.2, the ID should be non-zero. */
> > + if (id == 0) {
> > + dev_err(&dev->intf->dev, "Found Unit with invalid ID 0.\n");
>
> s/0./0/
>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
>
> Should I wait for Thadeu and Tomasz to check this new patch before
> applying it ?
It has been almost 3 weeks of radio-silence... I'd recommend to apply it.
We can always fix it afterwards.
>
> > + id = UVC_INVALID_ENTITY_ID;
> > + }
> > +
> > + /* Per UVC 1.1+ spec 3.7.2, the ID is unique. */
> > + if (uvc_entity_by_id(dev, id)) {
> > + dev_err(&dev->intf->dev, "Found multiple Units with ID %u\n", id);
> > + id = UVC_INVALID_ENTITY_ID;
> > + }
> > +
> > extra_size = roundup(extra_size, sizeof(*entity->pads));
> > if (num_pads)
> > num_inputs = type & UVC_TERM_OUTPUT ? num_pads : num_pads - 1;
> > @@ -812,7 +828,7 @@ static struct uvc_entity *uvc_alloc_entity(u16 type, u16 id,
> > + num_inputs;
> > entity = kzalloc(size, GFP_KERNEL);
> > if (entity == NULL)
> > - return NULL;
> > + return ERR_PTR(-ENOMEM);
> >
> > entity->id = id;
> > entity->type = type;
> > @@ -924,10 +940,10 @@ static int uvc_parse_vendor_control(struct uvc_device *dev,
> > break;
> > }
> >
> > - unit = uvc_alloc_entity(UVC_VC_EXTENSION_UNIT, buffer[3],
> > - p + 1, 2*n);
> > - if (unit == NULL)
> > - return -ENOMEM;
> > + unit = uvc_alloc_new_entity(dev, UVC_VC_EXTENSION_UNIT,
> > + buffer[3], p + 1, 2 * n);
> > + if (IS_ERR(unit))
> > + return PTR_ERR(unit);
> >
> > memcpy(unit->guid, &buffer[4], 16);
> > unit->extension.bNumControls = buffer[20];
> > @@ -1036,10 +1052,10 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
> > return -EINVAL;
> > }
> >
> > - term = uvc_alloc_entity(type | UVC_TERM_INPUT, buffer[3],
> > - 1, n + p);
> > - if (term == NULL)
> > - return -ENOMEM;
> > + term = uvc_alloc_new_entity(dev, type | UVC_TERM_INPUT,
> > + buffer[3], 1, n + p);
> > + if (IS_ERR(term))
> > + return PTR_ERR(term);
> >
> > if (UVC_ENTITY_TYPE(term) == UVC_ITT_CAMERA) {
> > term->camera.bControlSize = n;
> > @@ -1095,10 +1111,10 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
> > return 0;
> > }
> >
> > - term = uvc_alloc_entity(type | UVC_TERM_OUTPUT, buffer[3],
> > - 1, 0);
> > - if (term == NULL)
> > - return -ENOMEM;
> > + term = uvc_alloc_new_entity(dev, type | UVC_TERM_OUTPUT,
> > + buffer[3], 1, 0);
> > + if (IS_ERR(term))
> > + return PTR_ERR(term);
> >
> > memcpy(term->baSourceID, &buffer[7], 1);
> >
> > @@ -1117,9 +1133,10 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
> > return -EINVAL;
> > }
> >
> > - unit = uvc_alloc_entity(buffer[2], buffer[3], p + 1, 0);
> > - if (unit == NULL)
> > - return -ENOMEM;
> > + unit = uvc_alloc_new_entity(dev, buffer[2], buffer[3],
> > + p + 1, 0);
> > + if (IS_ERR(unit))
> > + return PTR_ERR(unit);
> >
> > memcpy(unit->baSourceID, &buffer[5], p);
> >
> > @@ -1139,9 +1156,9 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
> > return -EINVAL;
> > }
> >
> > - unit = uvc_alloc_entity(buffer[2], buffer[3], 2, n);
> > - if (unit == NULL)
> > - return -ENOMEM;
> > + unit = uvc_alloc_new_entity(dev, buffer[2], buffer[3], 2, n);
> > + if (IS_ERR(unit))
> > + return PTR_ERR(unit);
> >
> > memcpy(unit->baSourceID, &buffer[4], 1);
> > unit->processing.wMaxMultiplier =
> > @@ -1168,9 +1185,10 @@ static int uvc_parse_standard_control(struct uvc_device *dev,
> > return -EINVAL;
> > }
> >
> > - unit = uvc_alloc_entity(buffer[2], buffer[3], p + 1, n);
> > - if (unit == NULL)
> > - return -ENOMEM;
> > + unit = uvc_alloc_new_entity(dev, buffer[2], buffer[3],
> > + p + 1, n);
> > + if (IS_ERR(unit))
> > + return PTR_ERR(unit);
> >
> > memcpy(unit->guid, &buffer[4], 16);
> > unit->extension.bNumControls = buffer[20];
> > @@ -1315,9 +1333,10 @@ static int uvc_gpio_parse(struct uvc_device *dev)
> > return dev_err_probe(&dev->intf->dev, irq,
> > "No IRQ for privacy GPIO\n");
> >
> > - unit = uvc_alloc_entity(UVC_EXT_GPIO_UNIT, UVC_EXT_GPIO_UNIT_ID, 0, 1);
> > - if (!unit)
> > - return -ENOMEM;
> > + unit = uvc_alloc_new_entity(dev, UVC_EXT_GPIO_UNIT,
> > + UVC_EXT_GPIO_UNIT_ID, 0, 1);
> > + if (IS_ERR(unit))
> > + return PTR_ERR(unit);
> >
> > unit->gpio.gpio_privacy = gpio_privacy;
> > unit->gpio.irq = irq;
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index 70dc80e2b213dff333665022b3410b175d072793..881bfa0caab22714c26a3260cc843bda8e2706a4 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -41,6 +41,8 @@
> > #define UVC_EXT_GPIO_UNIT 0x7ffe
> > #define UVC_EXT_GPIO_UNIT_ID 0x100
> >
> > +#define UVC_INVALID_ENTITY_ID 0xffff
> > +
> > /* ------------------------------------------------------------------------
> > * Driver specific constants.
> > */
> >
> > ---
> > base-commit: a75b8d198c55e9eb5feb6f6e155496305caba2dc
> > change-id: 20250820-uvc-thadeu2-25723a961bd8
>
> --
> Regards,
>
> Laurent Pinchart
--
Ricardo Ribalda
Powered by blists - more mailing lists