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media: radio-raremono: change devm_k*alloc to k*alloc 

Change devm_k*alloc to k*alloc to manually allocate memory

The manual allocation and freeing of memory is necessary because when
the USB radio is disconnected, the memory associated with devm_k*alloc
is freed. Meaning if we still have unresolved references to the radio
device, then we get use-after-free errors.

This patch fixes this by manually allocating memory, and freeing it in
the v4l2.release callback that gets called when the last radio device
exits.

Reported-and-tested-by: syzbot+a4387f5b6b799f6becbf@syzkaller.appspotmail.com

Signed-off-by: Luke Nowakowski-Krijger <lnowakow@eng.ucsd.edu>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil-cisco@xs4all.nl: cleaned up two small checkpatch.pl warnings]
[hverkuil-cisco@xs4all.nl: prefix subject with driver name]
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Luke Nowakowski-Krijger 2019-06-21 21:04:38 -04:00 committed by Mauro Carvalho Chehab
parent b09a2ab2ba
commit c666355e60
1 changed files with 23 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/media/radio/radio-raremono.c
View File

@ -269,6 +269,14 @@ static int vidioc_g_frequency(struct file *file, void *priv,
return 0;
}
static void raremono_device_release(struct v4l2_device *v4l2_dev)
{
struct raremono_device *radio = to_raremono_dev(v4l2_dev);
kfree(radio->buffer);
kfree(radio);
}
/* File system interface */
static const struct v4l2_file_operations usb_raremono_fops = {
.owner = THIS_MODULE,
@ -293,12 +301,14 @@ static int usb_raremono_probe(struct usb_interface *intf,
struct raremono_device *radio;
int retval = 0;
radio = devm_kzalloc(&intf->dev, sizeof(struct raremono_device), GFP_KERNEL);
if (radio)
radio->buffer = devm_kmalloc(&intf->dev, BUFFER_LENGTH, GFP_KERNEL);
if (!radio || !radio->buffer)
radio = kzalloc(sizeof(*radio), GFP_KERNEL);
if (!radio)
return -ENOMEM;
radio->buffer = kmalloc(BUFFER_LENGTH, GFP_KERNEL);
if (!radio->buffer) {
kfree(radio);
return -ENOMEM;
}
radio->usbdev = interface_to_usbdev(intf);
radio->intf = intf;
@ -322,7 +332,8 @@ static int usb_raremono_probe(struct usb_interface *intf,
if (retval != 3 ||
(get_unaligned_be16(&radio->buffer[1]) & 0xfff) == 0x0242) {
dev_info(&intf->dev, "this is not Thanko's Raremono.\n");
return -ENODEV;
retval = -ENODEV;
goto free_mem;
}
dev_info(&intf->dev, "Thanko's Raremono connected: (%04X:%04X)\n",
@ -331,7 +342,7 @@ static int usb_raremono_probe(struct usb_interface *intf,
retval = v4l2_device_register(&intf->dev, &radio->v4l2_dev);
if (retval < 0) {
dev_err(&intf->dev, "couldn't register v4l2_device\n");
return retval;
goto free_mem;
}
mutex_init(&radio->lock);
@ -344,6 +355,7 @@ static int usb_raremono_probe(struct usb_interface *intf,
radio->vdev.lock = &radio->lock;
radio->vdev.release = video_device_release_empty;
radio->vdev.device_caps = V4L2_CAP_TUNER | V4L2_CAP_RADIO;
radio->v4l2_dev.release = raremono_device_release;
usb_set_intfdata(intf, &radio->v4l2_dev);
@ -359,6 +371,10 @@ static int usb_raremono_probe(struct usb_interface *intf,
}
dev_err(&intf->dev, "could not register video device\n");
v4l2_device_unregister(&radio->v4l2_dev);
free_mem:
kfree(radio->buffer);
kfree(radio);
return retval;
}