Add the missing bulk-endpoint max-packet sanity check to probe() to
avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
device has broken descriptors (or when doing descriptor fuzz testing).
Note that USB core will reject URBs submitted for endpoints with zero
wMaxPacketSize but that drivers doing packet-size calculations still
need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
endpoint descriptors with maxpacket=0")).
Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
Cc: [email protected] # 2.6.26
Signed-off-by: Johan Hovold <[email protected]>
---
drivers/media/usb/uvc/uvc_video.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
index e16464606b14..85ac5c1081b6 100644
--- a/drivers/media/usb/uvc/uvc_video.c
+++ b/drivers/media/usb/uvc/uvc_video.c
@@ -1958,6 +1958,10 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
if (ep == NULL)
return -EIO;
+ /* Reject broken descriptors. */
+ if (usb_endpoint_maxp(&ep->desc) == 0)
+ return -EIO;
+
ret = uvc_init_video_bulk(stream, ep, gfp_flags);
}
--
2.32.0
Quoting Johan Hovold (2021-10-26 10:55:11)
> Add the missing bulk-endpoint max-packet sanity check to probe() to
> avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
> device has broken descriptors (or when doing descriptor fuzz testing).
>
> Note that USB core will reject URBs submitted for endpoints with zero
> wMaxPacketSize but that drivers doing packet-size calculations still
> need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
> endpoint descriptors with maxpacket=0")).
>
> Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
> Cc: [email protected] # 2.6.26
> Signed-off-by: Johan Hovold <[email protected]>
> ---
> drivers/media/usb/uvc/uvc_video.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> index e16464606b14..85ac5c1081b6 100644
> --- a/drivers/media/usb/uvc/uvc_video.c
> +++ b/drivers/media/usb/uvc/uvc_video.c
> @@ -1958,6 +1958,10 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
> if (ep == NULL)
> return -EIO;
>
> + /* Reject broken descriptors. */
> + if (usb_endpoint_maxp(&ep->desc) == 0)
> + return -EIO;
Is there any value in identifying this with a specific return code like
-ENODATA?
But either way, this seems sane.
Reviewed-by: Kieran Bingham <[email protected]>
> +
> ret = uvc_init_video_bulk(stream, ep, gfp_flags);
> }
>
> --
> 2.32.0
>
On Tue, Oct 26, 2021 at 11:55:05AM +0100, Kieran Bingham wrote:
> Quoting Johan Hovold (2021-10-26 10:55:11)
> > Add the missing bulk-endpoint max-packet sanity check to probe() to
> > avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
> > device has broken descriptors (or when doing descriptor fuzz testing).
> >
> > Note that USB core will reject URBs submitted for endpoints with zero
> > wMaxPacketSize but that drivers doing packet-size calculations still
> > need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
> > endpoint descriptors with maxpacket=0")).
> >
> > Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
> > Cc: [email protected] # 2.6.26
> > Signed-off-by: Johan Hovold <[email protected]>
> > ---
> > drivers/media/usb/uvc/uvc_video.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > index e16464606b14..85ac5c1081b6 100644
> > --- a/drivers/media/usb/uvc/uvc_video.c
> > +++ b/drivers/media/usb/uvc/uvc_video.c
> > @@ -1958,6 +1958,10 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
> > if (ep == NULL)
> > return -EIO;
> >
> > + /* Reject broken descriptors. */
> > + if (usb_endpoint_maxp(&ep->desc) == 0)
> > + return -EIO;
>
> Is there any value in identifying this with a specific return code like
> -ENODATA?
Going one step further, wouldn't it be better to fail probe() for those
devices ?
> But either way, this seems sane.
>
> Reviewed-by: Kieran Bingham <[email protected]>
>
> > +
> > ret = uvc_init_video_bulk(stream, ep, gfp_flags);
> > }
> >
--
Regards,
Laurent Pinchart
On Tue, Oct 26, 2021 at 02:15:20PM +0300, Laurent Pinchart wrote:
> On Tue, Oct 26, 2021 at 11:55:05AM +0100, Kieran Bingham wrote:
> > Quoting Johan Hovold (2021-10-26 10:55:11)
> > > Add the missing bulk-endpoint max-packet sanity check to probe() to
> > > avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
> > > device has broken descriptors (or when doing descriptor fuzz testing).
> > >
> > > Note that USB core will reject URBs submitted for endpoints with zero
> > > wMaxPacketSize but that drivers doing packet-size calculations still
> > > need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
> > > endpoint descriptors with maxpacket=0")).
> > >
> > > Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
> > > Cc: [email protected] # 2.6.26
> > > Signed-off-by: Johan Hovold <[email protected]>
> > > ---
> > > drivers/media/usb/uvc/uvc_video.c | 4 ++++
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > > index e16464606b14..85ac5c1081b6 100644
> > > --- a/drivers/media/usb/uvc/uvc_video.c
> > > +++ b/drivers/media/usb/uvc/uvc_video.c
> > > @@ -1958,6 +1958,10 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
> > > if (ep == NULL)
> > > return -EIO;
> > >
> > > + /* Reject broken descriptors. */
> > > + if (usb_endpoint_maxp(&ep->desc) == 0)
> > > + return -EIO;
> >
> > Is there any value in identifying this with a specific return code like
> > -ENODATA?
>
> Going one step further, wouldn't it be better to fail probe() for those
> devices ?
This is not how the driver works today. Look at the "return -EIO" just
above in case the expected endpoint is missing. And similarly for the
isochronous case for which zero wMaxPacket isn't handled until
uvc_video_start_transfer() either (a few lines further up still).
Note however the copy-paste error in the commit message mentioning
probe(), which is indeed where this would typically be handled.
Do you want me to resend or can you change
s/probe()/uvc_video_start_transfer()/
in the commit message when applying if you think this is acceptable as
is?
Johan
Hi Johan,
On Tue, Oct 26, 2021 at 02:06:55PM +0200, Johan Hovold wrote:
> On Tue, Oct 26, 2021 at 02:15:20PM +0300, Laurent Pinchart wrote:
> > On Tue, Oct 26, 2021 at 11:55:05AM +0100, Kieran Bingham wrote:
> > > Quoting Johan Hovold (2021-10-26 10:55:11)
> > > > Add the missing bulk-endpoint max-packet sanity check to probe() to
> > > > avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
> > > > device has broken descriptors (or when doing descriptor fuzz testing).
> > > >
> > > > Note that USB core will reject URBs submitted for endpoints with zero
> > > > wMaxPacketSize but that drivers doing packet-size calculations still
> > > > need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
> > > > endpoint descriptors with maxpacket=0")).
> > > >
> > > > Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
> > > > Cc: [email protected] # 2.6.26
> > > > Signed-off-by: Johan Hovold <[email protected]>
> > > > ---
> > > > drivers/media/usb/uvc/uvc_video.c | 4 ++++
> > > > 1 file changed, 4 insertions(+)
> > > >
> > > > diff --git a/drivers/media/usb/uvc/uvc_video.c b/drivers/media/usb/uvc/uvc_video.c
> > > > index e16464606b14..85ac5c1081b6 100644
> > > > --- a/drivers/media/usb/uvc/uvc_video.c
> > > > +++ b/drivers/media/usb/uvc/uvc_video.c
> > > > @@ -1958,6 +1958,10 @@ static int uvc_video_start_transfer(struct uvc_streaming *stream,
> > > > if (ep == NULL)
> > > > return -EIO;
> > > >
> > > > + /* Reject broken descriptors. */
> > > > + if (usb_endpoint_maxp(&ep->desc) == 0)
> > > > + return -EIO;
> > >
> > > Is there any value in identifying this with a specific return code like
> > > -ENODATA?
> >
> > Going one step further, wouldn't it be better to fail probe() for those
> > devices ?
>
> This is not how the driver works today. Look at the "return -EIO" just
> above in case the expected endpoint is missing. And similarly for the
> isochronous case for which zero wMaxPacket isn't handled until
> uvc_video_start_transfer() either (a few lines further up still).
That's a good point, it wouldn't be reasonable to ask you to fix all
that :-)
> Note however the copy-paste error in the commit message mentioning
> probe(), which is indeed where this would typically be handled.
>
> Do you want me to resend or can you change
>
> s/probe()/uvc_video_start_transfer()/
>
> in the commit message when applying if you think this is acceptable as
> is?
I can fix this when applying.
Reviewed-by: Laurent Pinchart <[email protected]>
--
Regards,
Laurent Pinchart
On Wed, Oct 27, 2021 at 12:50:46AM +0300, Laurent Pinchart wrote:
> Hi Johan,
>
> On Tue, Oct 26, 2021 at 02:06:55PM +0200, Johan Hovold wrote:
> > Do you want me to resend or can you change
> >
> > s/probe()/uvc_video_start_transfer()/
> >
> > in the commit message when applying if you think this is acceptable as
> > is?
>
> I can fix this when applying.
Perfect, thanks.
> Reviewed-by: Laurent Pinchart <[email protected]>
Johan
Hi Laurent,
On Wed, Oct 27, 2021 at 12:50:46AM +0300, Laurent Pinchart wrote:
> Hi Johan,
>
> On Tue, Oct 26, 2021 at 02:06:55PM +0200, Johan Hovold wrote:
> > On Tue, Oct 26, 2021 at 02:15:20PM +0300, Laurent Pinchart wrote:
> > > On Tue, Oct 26, 2021 at 11:55:05AM +0100, Kieran Bingham wrote:
> > > > Quoting Johan Hovold (2021-10-26 10:55:11)
> > > > > Add the missing bulk-endpoint max-packet sanity check to probe() to
> > > > > avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
> > > > > device has broken descriptors (or when doing descriptor fuzz testing).
> > > > >
> > > > > Note that USB core will reject URBs submitted for endpoints with zero
> > > > > wMaxPacketSize but that drivers doing packet-size calculations still
> > > > > need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
> > > > > endpoint descriptors with maxpacket=0")).
> > > > >
> > > > > Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
> > > > > Cc: [email protected] # 2.6.26
> > > > > Signed-off-by: Johan Hovold <[email protected]>
> > Note however the copy-paste error in the commit message mentioning
> > probe(), which is indeed where this would typically be handled.
> >
> > Do you want me to resend or can you change
> >
> > s/probe()/uvc_video_start_transfer()/
> >
> > in the commit message when applying if you think this is acceptable as
> > is?
>
> I can fix this when applying.
>
> Reviewed-by: Laurent Pinchart <[email protected]>
I noticed that this one hasn't showed up in linux-next yet. Do you still
have it in your queue or do you want me to resend?
Johan
Hi Johan,
On Fri, Dec 03, 2021 at 11:29:07AM +0100, Johan Hovold wrote:
> On Wed, Oct 27, 2021 at 12:50:46AM +0300, Laurent Pinchart wrote:
> > On Tue, Oct 26, 2021 at 02:06:55PM +0200, Johan Hovold wrote:
> > > On Tue, Oct 26, 2021 at 02:15:20PM +0300, Laurent Pinchart wrote:
> > > > On Tue, Oct 26, 2021 at 11:55:05AM +0100, Kieran Bingham wrote:
> > > > > Quoting Johan Hovold (2021-10-26 10:55:11)
> > > > > > Add the missing bulk-endpoint max-packet sanity check to probe() to
> > > > > > avoid division by zero in uvc_alloc_urb_buffers() in case a malicious
> > > > > > device has broken descriptors (or when doing descriptor fuzz testing).
> > > > > >
> > > > > > Note that USB core will reject URBs submitted for endpoints with zero
> > > > > > wMaxPacketSize but that drivers doing packet-size calculations still
> > > > > > need to handle this (cf. commit 2548288b4fb0 ("USB: Fix: Don't skip
> > > > > > endpoint descriptors with maxpacket=0")).
> > > > > >
> > > > > > Fixes: c0efd232929c ("V4L/DVB (8145a): USB Video Class driver")
> > > > > > Cc: [email protected] # 2.6.26
> > > > > > Signed-off-by: Johan Hovold <[email protected]>
> > >
> > > Note however the copy-paste error in the commit message mentioning
> > > probe(), which is indeed where this would typically be handled.
> > >
> > > Do you want me to resend or can you change
> > >
> > > s/probe()/uvc_video_start_transfer()/
> > >
> > > in the commit message when applying if you think this is acceptable as
> > > is?
> >
> > I can fix this when applying.
> >
> > Reviewed-by: Laurent Pinchart <[email protected]>
>
> I noticed that this one hasn't showed up in linux-next yet. Do you still
> have it in your queue or do you want me to resend?
It should be in Mauro's queue now:
https://lore.kernel.org/all/[email protected]/
--
Regards,
Laurent Pinchart
On Fri, Dec 03, 2021 at 12:52:19PM +0200, Laurent Pinchart wrote:
> > I noticed that this one hasn't showed up in linux-next yet. Do you still
> > have it in your queue or do you want me to resend?
>
> It should be in Mauro's queue now:
>
> https://lore.kernel.org/all/[email protected]/
Perfect, thanks!
Johan