| Message ID | 20210120102057.21143-3-tiwai@suse.de |
|---|---|
| State | Superseded |
| Headers | show |
| Series | media: dvb-usb: Fix UAF and memory leaks | expand |
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@linaro.org> On Wed, 20 Jan 2021 at 12:51, Takashi Iwai <tiwai@suse.de> 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@b1-systems.com> > BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1181104 > Cc: <stable@vger.kernel.org> > Signed-off-by: Takashi Iwai <tiwai@suse.de> > --- > 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 >
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@linaro.org> > > On Wed, 20 Jan 2021 at 12:51, Takashi Iwai <tiwai@suse.de> 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@b1-systems.com> > > BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1181104 > > Cc: <stable@vger.kernel.org> > > Signed-off-by: Takashi Iwai <tiwai@suse.de> 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 > >
On Sun, 31 Jan 2021 16:04:56 +0100, Sean Young wrote: > > 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. It's case-by-case, checkpatch is no bible by itself. In this particular case, it was rather a false-positive of checkpatch: the commit reference including a line-break. This issue has been always annoying and I wish this will be dropped from checkpatch in near future... thanks, Takashi
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;
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@b1-systems.com> BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1181104 Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> --- drivers/media/usb/dvb-usb/dvb-usb-init.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-)