Hi Takashi, On Fri, Jan 22, 2021 at 04:47:44PM +0100, Robert Foss wrote: > Hey Takashi, > > This patch is generating a checkpatch warning, but I think it is > spurious and can be ignored. The checkpatch warning isn't superious and should really be corrected. > > 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> Thank you for your patch. Unfortunately, it depends on the first patch in the series, which I think has problems (see email about this). Thanks Sean > > --- > > 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 > >
