linux-stable.git/drivers/media/usb, branch linux-3.16.y

media: uvcvideo: Avoid cyclic entity chains due to malformed USB descriptors

2020-05-22T20:19:33+00:00

commit 68035c80e129c4cfec659aac4180354530b26527 upstream.

Way back in 2017, fuzzing the 4.14-rc2 USB stack with syzkaller kicked
up the following WARNING from the UVC chain scanning code:

  | list_add double add: new=ffff880069084010, prev=ffff880069084010,
  | next=ffff880067d22298.
  | ------------[ cut here ]------------
  | WARNING: CPU: 1 PID: 1846 at lib/list_debug.c:31 __list_add_valid+0xbd/0xf0
  | Modules linked in:
  | CPU: 1 PID: 1846 Comm: kworker/1:2 Not tainted
  | 4.14.0-rc2-42613-g1488251d1a98 #238
  | Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  | Workqueue: usb_hub_wq hub_event
  | task: ffff88006b01ca40 task.stack: ffff880064358000
  | RIP: 0010:__list_add_valid+0xbd/0xf0 lib/list_debug.c:29
  | RSP: 0018:ffff88006435ddd0 EFLAGS: 00010286
  | RAX: 0000000000000058 RBX: ffff880067d22298 RCX: 0000000000000000
  | RDX: 0000000000000058 RSI: ffffffff85a58800 RDI: ffffed000c86bbac
  | RBP: ffff88006435dde8 R08: 1ffff1000c86ba52 R09: 0000000000000000
  | R10: 0000000000000002 R11: 0000000000000000 R12: ffff880069084010
  | R13: ffff880067d22298 R14: ffff880069084010 R15: ffff880067d222a0
  | FS:  0000000000000000(0000) GS:ffff88006c900000(0000) knlGS:0000000000000000
  | CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  | CR2: 0000000020004ff2 CR3: 000000006b447000 CR4: 00000000000006e0
  | Call Trace:
  |  __list_add ./include/linux/list.h:59
  |  list_add_tail+0x8c/0x1b0 ./include/linux/list.h:92
  |  uvc_scan_chain_forward.isra.8+0x373/0x416
  | drivers/media/usb/uvc/uvc_driver.c:1471
  |  uvc_scan_chain drivers/media/usb/uvc/uvc_driver.c:1585
  |  uvc_scan_device drivers/media/usb/uvc/uvc_driver.c:1769
  |  uvc_probe+0x77f2/0x8f00 drivers/media/usb/uvc/uvc_driver.c:2104

Looking into the output from usbmon, the interesting part is the
following data packet:

  ffff880069c63e00 30710169 C Ci:1:002:0 0 143 = 09028f00 01030080
  00090403 00000e01 00000924 03000103 7c003328 010204db

If we drop the lead configuration and interface descriptors, we're left
with an output terminal descriptor describing a generic display:

  /* Output terminal descriptor */
  buf[0]	09
  buf[1]	24
  buf[2]	03	/* UVC_VC_OUTPUT_TERMINAL */
  buf[3]	00	/* ID */
  buf[4]	01	/* type == 0x0301 (UVC_OTT_DISPLAY) */
  buf[5]	03
  buf[6]	7c
  buf[7]	00	/* source ID refers to self! */
  buf[8]	33

The problem with this descriptor is that it is self-referential: the
source ID of 0 matches itself! This causes the 'struct uvc_entity'
representing the display to be added to its chain list twice during
'uvc_scan_chain()': once via 'uvc_scan_chain_entity()' when it is
processed directly from the 'dev->entities' list and then again
immediately afterwards when trying to follow the source ID in
'uvc_scan_chain_forward()'

Add a check before adding an entity to a chain list to ensure that the
entity is not already part of a chain.

Link: https://lore.kernel.org/linux-media/CAAeHK+z+Si69jUR+N-SjN9q4O+o5KFiNManqEa-PjUta7EOb7A@mail.gmail.com/

Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
Reported-by: Andrey Konovalov 
Signed-off-by: Will Deacon 
Signed-off-by: Laurent Pinchart 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Ben Hutchings

media-device: dynamically allocate struct media_devnode

2020-04-28T18:03:50+00:00

commit a087ce704b802becbb4b0f2a20f2cb3f6911802e upstream.

struct media_devnode is currently embedded at struct media_device.

While this works fine during normal usage, it leads to a race
condition during devnode unregister. the problem is that drivers
assume that, after calling media_device_unregister(), the struct
that contains media_device can be freed. This is not true, as it
can't be freed until userspace closes all opened /dev/media devnodes.

In other words, if the media devnode is still open, and media_device
gets freed, any call to an ioctl will make the core to try to access
struct media_device, with will cause an use-after-free and even GPF.

Fix this by dynamically allocating the struct media_devnode and only
freeing it when it is safe.

Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Mauro Carvalho Chehab 
[bwh: Backported to 3.16:
 - Drop change in au0828
 - Include  in media-device.c
 - Adjust context]
Signed-off-by: Ben Hutchings

media: xirlink_cit: add missing descriptor sanity checks

2020-04-28T18:03:44+00:00

commit a246b4d547708f33ff4d4b9a7a5dbac741dc89d8 upstream.

Make sure to check that we have two alternate settings and at least one
endpoint before accessing the second altsetting structure and
dereferencing the endpoint arrays.

This specifically avoids dereferencing NULL-pointers or corrupting
memory when a device does not have the expected descriptors.

Note that the sanity check in cit_get_packet_size() is not redundant as
the driver is mixing looking up altsettings by index and by number,
which may not coincide.

Fixes: 659fefa0eb17 ("V4L/DVB: gspca_xirlink_cit: Add support for camera with a bcd version of 0.01")
Fixes: 59f8b0bf3c12 ("V4L/DVB: gspca_xirlink_cit: support bandwidth changing for devices with 1 alt setting")
Cc: Hans de Goede 
Signed-off-by: Johan Hovold 
Signed-off-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Ben Hutchings

media: stv06xx: add missing descriptor sanity checks

2020-04-28T18:03:44+00:00

commit 485b06aadb933190f4bc44e006076bc27a23f205 upstream.

Make sure to check that we have two alternate settings and at least one
endpoint before accessing the second altsetting structure and
dereferencing the endpoint arrays.

This specifically avoids dereferencing NULL-pointers or corrupting
memory when a device does not have the expected descriptors.

Note that the sanity checks in stv06xx_start() and pb0100_start() are
not redundant as the driver is mixing looking up altsettings by index
and by number, which may not coincide.

Fixes: 8668d504d72c ("V4L/DVB (12082): gspca_stv06xx: Add support for st6422 bridge and sensor")
Fixes: c0b33bdc5b8d ("[media] gspca-stv06xx: support bandwidth changing")
Cc: Hans de Goede 
Signed-off-by: Johan Hovold 
Signed-off-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Ben Hutchings

media: ov519: add missing endpoint sanity checks

2020-04-28T18:03:44+00:00

commit 998912346c0da53a6dbb71fab3a138586b596b30 upstream.

Make sure to check that we have at least one endpoint before accessing
the endpoint array to avoid dereferencing a NULL-pointer on stream
start.

Note that these sanity checks are not redundant as the driver is mixing
looking up altsettings by index and by number, which need not coincide.

Fixes: 1876bb923c98 ("V4L/DVB (12079): gspca_ov519: add support for the ov511 bridge")
Fixes: b282d87332f5 ("V4L/DVB (12080): gspca_ov519: Fix ov518+ with OV7620AE (Trust spacecam 320)")
Cc: Hans de Goede 
Signed-off-by: Johan Hovold 
Signed-off-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Ben Hutchings

media: usbvision: Fix races among open, close, and disconnect

2020-02-11T20:03:17+00:00

commit 9e08117c9d4efc1e1bc6fce83dab856d9fd284b6 upstream.

Visual inspection of the usbvision driver shows that it suffers from
three races between its open, close, and disconnect handlers.  In
particular, the driver is careful to update its usbvision->user and
usbvision->remove_pending flags while holding the private mutex, but:

	usbvision_v4l2_close() and usbvision_radio_close() don't hold
	the mutex while they check the value of
	usbvision->remove_pending;

	usbvision_disconnect() doesn't hold the mutex while checking
	the value of usbvision->user; and

	also, usbvision_v4l2_open() and usbvision_radio_open() don't
	check whether the device has been unplugged before allowing
	the user to open the device files.

Each of these can potentially lead to usbvision_release() being called
twice and use-after-free errors.

This patch fixes the races by reading the flags while the mutex is
still held and checking for pending removes before allowing an open to
succeed.

Signed-off-by: Alan Stern 
Signed-off-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
[bwh: Backported to 3.16:
 - Add unlock label in usbvision_v4l2_open()
 - Adjust context]
Signed-off-by: Ben Hutchings

media: usbvision: Fix invalid accesses after device disconnect

2020-02-11T20:03:17+00:00

commit c7a191464078262bf799136317c95824e26a222b upstream.

The syzbot fuzzer found two invalid-access bugs in the usbvision
driver.  These bugs occur when userspace keeps the device file open
after the device has been disconnected and usbvision_disconnect() has
set usbvision->dev to NULL:

	When the device file is closed, usbvision_radio_close() tries
	to issue a usb_set_interface() call, passing the NULL pointer
	as its first argument.

	If userspace performs a querycap ioctl call, vidioc_querycap()
	calls usb_make_path() with the same NULL pointer.

This patch fixes the problems by making the appropriate tests
beforehand.  Note that vidioc_querycap() is protected by
usbvision->v4l2_lock, acquired in a higher layer of the V4L2
subsystem.

Reported-and-tested-by: syzbot+7fa38a608b1075dfd634@syzkaller.appspotmail.com

Signed-off-by: Alan Stern 
Signed-off-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

usbvision: fix locking error

2020-02-11T20:03:16+00:00

commit 5ce625a42d6206d5a18222c6475f6b866ef68569 upstream.

When remove_pending is non-zero, v4l2_lock is never unlocked.

Signed-off-by: Insu Yun 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Ben Hutchings

usbvision: fix locking error

2020-02-11T20:03:16+00:00

commit e2c84ccb0fbe5e524d15bb09c042a6ca634adaed upstream.

If remove_pending is non-zero, then the v4l2_lock is never unlocked.

Signed-off-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Ben Hutchings

usbvision-video: two use after frees

2020-02-11T20:03:16+00:00

commit 470a9147899500eb4898f77816520c4b4aa1a698 upstream.

The lock has been freed in usbvision_release() so there is no need to
call mutex_unlock() here.

Signed-off-by: Dan Carpenter 
Signed-off-by: Hans Verkuil 
Signed-off-by: Mauro Carvalho Chehab 
Signed-off-by: Ben Hutchings