Hey Takashi, This patch is generating a checkpatch warning, but I think it is spurious and can be ignored. Other than that, this looks good to me. Reviewed-by: Robert Foss <robert.foss@xxxxxxxxxx> On Wed, 20 Jan 2021 at 12:51, Takashi Iwai <tiwai@xxxxxxx> wrote: > > dvb_usb_device_init() copies the properties to the own data, so that > the callers can release the original properties later (as done in the > commit 299c7007e936 "media: dw2102: Fix memleak on sequence of > probes"). However, it also stores dev->desc pointer that is a > reference to the original properties data. Since dev->desc is > referred later, it may result in use-after-free, in the worst case, > leading to a kernel Oops as reported. > > This patch addresses the problem by allocating and copying the > properties at first, then get the desc from the copied properties. > > Reported-and-tested-by: Stefan Seyfried <seife+kernel@xxxxxxxxxxxxxx> > BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1181104 > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> > --- > drivers/media/usb/dvb-usb/dvb-usb-init.c | 23 +++++++++++++---------- > 1 file changed, 13 insertions(+), 10 deletions(-) > > diff --git a/drivers/media/usb/dvb-usb/dvb-usb-init.c b/drivers/media/usb/dvb-usb/dvb-usb-init.c > index 5befec87f26a..07ff9b4d2f34 100644 > --- a/drivers/media/usb/dvb-usb/dvb-usb-init.c > +++ b/drivers/media/usb/dvb-usb/dvb-usb-init.c > @@ -255,27 +255,30 @@ int dvb_usb_device_init(struct usb_interface *intf, > if (du != NULL) > *du = NULL; > > - if ((desc = dvb_usb_find_device(udev, props, &cold)) == NULL) { > + d = kzalloc(sizeof(struct dvb_usb_device), GFP_KERNEL); > + if (!d) { > + err("no memory for 'struct dvb_usb_device'"); > + return -ENOMEM; > + } > + > + memcpy(&d->props, props, sizeof(struct dvb_usb_device_properties)); > + > + desc = dvb_usb_find_device(udev, &d->props, &cold); > + if (!desc) { > deb_err("something went very wrong, device was not found in current device list - let's see what comes next.\n"); > - return -ENODEV; > + ret = -ENODEV; > + goto error; > } > > if (cold) { > info("found a '%s' in cold state, will try to load a firmware", desc->name); > ret = dvb_usb_download_firmware(udev, props); > if (!props->no_reconnect || ret != 0) > - return ret; > + goto error; > } > > info("found a '%s' in warm state.", desc->name); > - d = kzalloc(sizeof(struct dvb_usb_device), GFP_KERNEL); > - if (d == NULL) { > - err("no memory for 'struct dvb_usb_device'"); > - return -ENOMEM; > - } > - > d->udev = udev; > - memcpy(&d->props, props, sizeof(struct dvb_usb_device_properties)); > d->desc = desc; > d->owner = owner; > > -- > 2.26.2 >
