From c666355e60ddb4748ead3bdd983e3f7f2224aaf0 Mon Sep 17 00:00:00 2001 From: Luke Nowakowski-Krijger Date: Fri, 21 Jun 2019 21:04:38 -0400 Subject: 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 Signed-off-by: Hans Verkuil [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 --- drivers/media/radio/radio-raremono.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) (limited to 'drivers/media') diff --git a/drivers/media/radio/radio-raremono.c b/drivers/media/radio/radio-raremono.c index 606f588e1edf..c3180d53c282 100644 --- a/drivers/media/radio/radio-raremono.c +++ b/drivers/media/radio/radio-raremono.c @@ -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; } -- cgit v1.2.3-59-g8ed1b