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, ``` So, deny allocating an entity with ID 0 or an ID that belongs to a unit that is already added to the list of entities. 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> Reported-by: syzbot+0584f746fde3d52b4675@xxxxxxxxxxxxxxxxxxxxxxxxx Closes: https://syzkaller.appspot.com/bug?extid=0584f746fde3d52b4675 Reported-by: syzbot+dd320d114deb3f5bb79b@xxxxxxxxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxx> --- drivers/media/usb/uvc/uvc_driver.c | 70 ++++++++++++++++++------------ 1 file changed, 43 insertions(+), 27 deletions(-) diff --git a/drivers/media/usb/uvc/uvc_driver.c b/drivers/media/usb/uvc/uvc_driver.c index f0febdc08c2d..3daa93a29776 100644 --- a/drivers/media/usb/uvc/uvc_driver.c +++ b/drivers/media/usb/uvc/uvc_driver.c @@ -775,14 +775,27 @@ 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 is unique */ + if (uvc_entity_by_id(dev, id)) { + dev_err(&dev->udev->dev, "Found multiple Units with the same ID.\n"); + return ERR_PTR(-EINVAL); + } + + /* Per UVC 1.1+ spec 3.7.2, the ID should be non-zero */ + if (id == 0) { + dev_err(&dev->udev->dev, "Found Unit with invalid ID 0.\n"); + return ERR_PTR(-EINVAL); + } + extra_size = roundup(extra_size, sizeof(*entity->pads)); if (num_pads) num_inputs = type & UVC_TERM_OUTPUT ? num_pads : num_pads - 1; @@ -792,7 +805,7 @@ 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; @@ -904,10 +917,10 @@ 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]; @@ -1016,10 +1029,10 @@ 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; @@ -1075,10 +1088,10 @@ 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); @@ -1097,9 +1110,10 @@ 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); @@ -1119,9 +1133,9 @@ 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 = @@ -1148,9 +1162,10 @@ 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]; @@ -1290,9 +1305,10 @@ static int uvc_gpio_parse(struct uvc_device *dev) return dev_err_probe(&dev->udev->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; -- 2.34.1
