From: Luke Nowakowski-Krijger lnowakow@eng.ucsd.edu
[ Upstream commit d4a6a9537bc32811486282206ecfb7c53754b74d ]
Add hdpvr device num check and error handling
We need to increment the device count atomically before we checkout a device to make sure that we do not reach the max count, otherwise we get out-of-bounds errors as reported by syzbot.
Reported-and-tested-by: syzbot+aac8d0d7205f112045d2@syzkaller.appspotmail.com
Signed-off-by: Luke Nowakowski-Krijger lnowakow@eng.ucsd.edu Signed-off-by: Hans Verkuil hverkuil-cisco@xs4all.nl Signed-off-by: Mauro Carvalho Chehab mchehab+samsung@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/media/usb/hdpvr/hdpvr-core.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/media/usb/hdpvr/hdpvr-core.c b/drivers/media/usb/hdpvr/hdpvr-core.c index 1e8cbaf368961..416092c47ef40 100644 --- a/drivers/media/usb/hdpvr/hdpvr-core.c +++ b/drivers/media/usb/hdpvr/hdpvr-core.c @@ -275,6 +275,7 @@ static int hdpvr_probe(struct usb_interface *interface, #endif size_t buffer_size; int i; + int dev_num; int retval = -ENOMEM;
/* allocate memory for our device state and initialize it */ @@ -379,8 +380,17 @@ static int hdpvr_probe(struct usb_interface *interface, } #endif
+ dev_num = atomic_inc_return(&dev_nr); + if (dev_num >= HDPVR_MAX) { + v4l2_err(&dev->v4l2_dev, + "max device number reached, device register failed\n"); + atomic_dec(&dev_nr); + retval = -ENODEV; + goto reg_fail; + } + retval = hdpvr_register_videodev(dev, &interface->dev, - video_nr[atomic_inc_return(&dev_nr)]); + video_nr[dev_num]); if (retval < 0) { v4l2_err(&dev->v4l2_dev, "registering videodev failed\n"); goto reg_fail;