3.16.74-rc1 review patch. If anyone has any objections, please let me know.
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From: Luke Nowakowski-Krijger lnowakow@eng.ucsd.edu
commit c666355e60ddb4748ead3bdd983e3f7f2224aaf0 upstream.
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 [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/media/radio/radio-raremono.c | 30 +++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-)
--- a/drivers/media/radio/radio-raremono.c +++ b/drivers/media/radio/radio-raremono.c @@ -283,6 +283,14 @@ static int vidioc_g_frequency(struct fil 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, @@ -307,12 +315,14 @@ static int usb_raremono_probe(struct usb 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; @@ -336,7 +346,8 @@ static int usb_raremono_probe(struct usb 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", @@ -345,7 +356,7 @@ static int usb_raremono_probe(struct usb 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); @@ -357,6 +368,7 @@ static int usb_raremono_probe(struct usb radio->vdev.ioctl_ops = &usb_raremono_ioctl_ops; radio->vdev.lock = &radio->lock; radio->vdev.release = video_device_release_empty; + radio->v4l2_dev.release = raremono_device_release;
usb_set_intfdata(intf, &radio->v4l2_dev);
@@ -373,6 +385,10 @@ static int usb_raremono_probe(struct usb } 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; }