<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/usb/core/devio.c, branch linux-4.9.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>USB: core: Change %pK for __user pointers to %px</title>
<updated>2020-12-02T07:31:28+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2020-11-19T17:02:28+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eca70659fd7c60a2e3c718b7e82edfb1509805c4'/>
<id>eca70659fd7c60a2e3c718b7e82edfb1509805c4</id>
<content type='text'>
commit f3bc432aa8a7a2bfe9ebb432502be5c5d979d7fe upstream.

Commit 2f964780c03b ("USB: core: replace %p with %pK") used the %pK
format specifier for a bunch of __user pointers.  But as the 'K' in
the specifier indicates, it is meant for kernel pointers.  The reason
for the %pK specifier is to avoid leaks of kernel addresses, but when
the pointer is to an address in userspace the security implications
are minimal.  In particular, no kernel information is leaked.

This patch changes the __user %pK specifiers (used in a bunch of
debugging output lines) to %px, which will always print the actual
address with no mangling.  (Notably, there is no printk format
specifier particularly intended for __user pointers.)

Fixes: 2f964780c03b ("USB: core: replace %p with %pK")
CC: Vamsi Krishna Samavedam &lt;vskrishn@codeaurora.org&gt;
CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/20201119170228.GB576844@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit f3bc432aa8a7a2bfe9ebb432502be5c5d979d7fe upstream.

Commit 2f964780c03b ("USB: core: replace %p with %pK") used the %pK
format specifier for a bunch of __user pointers.  But as the 'K' in
the specifier indicates, it is meant for kernel pointers.  The reason
for the %pK specifier is to avoid leaks of kernel addresses, but when
the pointer is to an address in userspace the security implications
are minimal.  In particular, no kernel information is leaked.

This patch changes the __user %pK specifiers (used in a bunch of
debugging output lines) to %px, which will always print the actual
address with no mangling.  (Notably, there is no printk format
specifier particularly intended for __user pointers.)

Fixes: 2f964780c03b ("USB: core: replace %p with %pK")
CC: Vamsi Krishna Samavedam &lt;vskrishn@codeaurora.org&gt;
CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Link: https://lore.kernel.org/r/20201119170228.GB576844@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>usb: usbfs: Suppress problematic bind and unbind uevents.</title>
<updated>2020-01-04T12:39:24+00:00</updated>
<author>
<name>Ingo Rohloff</name>
<email>ingo.rohloff@lauterbach.com</email>
</author>
<published>2019-10-11T11:55:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=aaaf3afc2dde1026231d41d84a2cfc7e896d11a1'/>
<id>aaaf3afc2dde1026231d41d84a2cfc7e896d11a1</id>
<content type='text'>
[ Upstream commit abb0b3d96a1f9407dd66831ae33985a386d4200d ]

commit 1455cf8dbfd0 ("driver core: emit uevents when device is bound
to a driver") added bind and unbind uevents when a driver is bound or
unbound to a physical device.

For USB devices which are handled via the generic usbfs layer (via
libusb for example), this is problematic:
Each time a user space program calls
   ioctl(usb_fd, USBDEVFS_CLAIMINTERFACE, &amp;usb_intf_nr);
and then later
   ioctl(usb_fd, USBDEVFS_RELEASEINTERFACE, &amp;usb_intf_nr);
The kernel will now produce a bind or unbind event, which does not
really contain any useful information.

This allows a user space program to run a DoS attack against programs
which listen to uevents (in particular systemd/eudev/upowerd):
A malicious user space program just has to call in a tight loop

   ioctl(usb_fd, USBDEVFS_CLAIMINTERFACE, &amp;usb_intf_nr);
   ioctl(usb_fd, USBDEVFS_RELEASEINTERFACE, &amp;usb_intf_nr);

With this loop the malicious user space program floods the kernel and
all programs listening to uevents with tons of bind and unbind
events.

This patch suppresses uevents for ioctls USBDEVFS_CLAIMINTERFACE and
USBDEVFS_RELEASEINTERFACE.

Signed-off-by: Ingo Rohloff &lt;ingo.rohloff@lauterbach.com&gt;
Link: https://lore.kernel.org/r/20191011115518.2801-1-ingo.rohloff@lauterbach.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit abb0b3d96a1f9407dd66831ae33985a386d4200d ]

commit 1455cf8dbfd0 ("driver core: emit uevents when device is bound
to a driver") added bind and unbind uevents when a driver is bound or
unbound to a physical device.

For USB devices which are handled via the generic usbfs layer (via
libusb for example), this is problematic:
Each time a user space program calls
   ioctl(usb_fd, USBDEVFS_CLAIMINTERFACE, &amp;usb_intf_nr);
and then later
   ioctl(usb_fd, USBDEVFS_RELEASEINTERFACE, &amp;usb_intf_nr);
The kernel will now produce a bind or unbind event, which does not
really contain any useful information.

This allows a user space program to run a DoS attack against programs
which listen to uevents (in particular systemd/eudev/upowerd):
A malicious user space program just has to call in a tight loop

   ioctl(usb_fd, USBDEVFS_CLAIMINTERFACE, &amp;usb_intf_nr);
   ioctl(usb_fd, USBDEVFS_RELEASEINTERFACE, &amp;usb_intf_nr);

With this loop the malicious user space program floods the kernel and
all programs listening to uevents with tons of bind and unbind
events.

This patch suppresses uevents for ioctls USBDEVFS_CLAIMINTERFACE and
USBDEVFS_RELEASEINTERFACE.

Signed-off-by: Ingo Rohloff &lt;ingo.rohloff@lauterbach.com&gt;
Link: https://lore.kernel.org/r/20191011115518.2801-1-ingo.rohloff@lauterbach.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>usb: usbfs: fix double-free of usb memory upon submiturb error</title>
<updated>2019-08-25T08:51:17+00:00</updated>
<author>
<name>Gavin Li</name>
<email>git@thegavinli.com</email>
</author>
<published>2019-08-04T23:50:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=eb7124b0cca13de746719238eceba21537e8b396'/>
<id>eb7124b0cca13de746719238eceba21537e8b396</id>
<content type='text'>
commit c43f28dfdc4654e738aa6d3fd08a105b2bee758d upstream.

Upon an error within proc_do_submiturb(), dec_usb_memory_use_count()
gets called once by the error handling tail and again by free_async().
Remove the first call.

Signed-off-by: Gavin Li &lt;git@thegavinli.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20190804235044.22327-1-gavinli@thegavinli.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit c43f28dfdc4654e738aa6d3fd08a105b2bee758d upstream.

Upon an error within proc_do_submiturb(), dec_usb_memory_use_count()
gets called once by the error handling tail and again by free_async().
Remove the first call.

Signed-off-by: Gavin Li &lt;git@thegavinli.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Cc: stable &lt;stable@vger.kernel.org&gt;
Link: https://lore.kernel.org/r/20190804235044.22327-1-gavinli@thegavinli.com
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: fix the usbfs flag sanitization for control transfers</title>
<updated>2018-11-10T15:43:00+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2018-10-15T20:55:04+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=bdbb426f6e1c397ae567f1d38a522270d9cfe2e9'/>
<id>bdbb426f6e1c397ae567f1d38a522270d9cfe2e9</id>
<content type='text'>
commit 665c365a77fbfeabe52694aedf3446d5f2f1ce42 upstream.

Commit 7a68d9fb8510 ("USB: usbdevfs: sanitize flags more") checks the
transfer flags for URBs submitted from userspace via usbfs.  However,
the check for whether the USBDEVFS_URB_SHORT_NOT_OK flag should be
allowed for a control transfer was added in the wrong place, before
the code has properly determined the direction of the control
transfer.  (Control transfers are special because for them, the
direction is set by the bRequestType byte of the Setup packet rather
than direction bit of the endpoint address.)

This patch moves code which sets up the allow_short flag for control
transfers down after is_in has been set to the correct value.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: syzbot+24a30223a4b609bb802e@syzkaller.appspotmail.com
Fixes: 7a68d9fb8510 ("USB: usbdevfs: sanitize flags more")
CC: Oliver Neukum &lt;oneukum@suse.com&gt;
CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 665c365a77fbfeabe52694aedf3446d5f2f1ce42 upstream.

Commit 7a68d9fb8510 ("USB: usbdevfs: sanitize flags more") checks the
transfer flags for URBs submitted from userspace via usbfs.  However,
the check for whether the USBDEVFS_URB_SHORT_NOT_OK flag should be
allowed for a control transfer was added in the wrong place, before
the code has properly determined the direction of the control
transfer.  (Control transfers are special because for them, the
direction is set by the bRequestType byte of the Setup packet rather
than direction bit of the endpoint address.)

This patch moves code which sets up the allow_short flag for control
transfers down after is_in has been set to the correct value.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Reported-and-tested-by: syzbot+24a30223a4b609bb802e@syzkaller.appspotmail.com
Fixes: 7a68d9fb8510 ("USB: usbdevfs: sanitize flags more")
CC: Oliver Neukum &lt;oneukum@suse.com&gt;
CC: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: usbdevfs: restore warning for nonsensical flags</title>
<updated>2018-10-04T00:01:50+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2018-09-05T10:07:03+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=35d7a3bb6d5dd8214f61e7de7289acffd3f8ee22'/>
<id>35d7a3bb6d5dd8214f61e7de7289acffd3f8ee22</id>
<content type='text'>
commit 81e0403b26d94360abd1f6a57311337973bc82cd upstream.

If we filter flags before they reach the core we need to generate our
own warnings.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Fixes: 0cb54a3e47cb ("USB: debugging code shouldn't alter control flow")
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 81e0403b26d94360abd1f6a57311337973bc82cd upstream.

If we filter flags before they reach the core we need to generate our
own warnings.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Fixes: 0cb54a3e47cb ("USB: debugging code shouldn't alter control flow")
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: usbdevfs: sanitize flags more</title>
<updated>2018-10-04T00:01:50+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2018-09-05T10:07:02+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a2ecf4329fe1c334b7341c20beb90ba02bf9e76c'/>
<id>a2ecf4329fe1c334b7341c20beb90ba02bf9e76c</id>
<content type='text'>
commit 7a68d9fb851012829c29e770621905529bd9490b upstream.

Requesting a ZERO_PACKET or not is sensible only for output.
In the input direction the device decides.
Likewise accepting short packets makes sense only for input.

This allows operation with panic_on_warn without opening up
a local DOS.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Reported-by: syzbot+843efa30c8821bd69f53@syzkaller.appspotmail.com
Fixes: 0cb54a3e47cb ("USB: debugging code shouldn't alter control flow")
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7a68d9fb851012829c29e770621905529bd9490b upstream.

Requesting a ZERO_PACKET or not is sensible only for output.
In the input direction the device decides.
Likewise accepting short packets makes sense only for input.

This allows operation with panic_on_warn without opening up
a local DOS.

Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Reported-by: syzbot+843efa30c8821bd69f53@syzkaller.appspotmail.com
Fixes: 0cb54a3e47cb ("USB: debugging code shouldn't alter control flow")
Cc: stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: usbfs: Filter flags passed in from user space</title>
<updated>2017-12-09T21:01:57+00:00</updated>
<author>
<name>Oliver Neukum</name>
<email>oneukum@suse.com</email>
</author>
<published>2017-11-23T15:39:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=20c315ebabc5a63b0bb169ddd60455ee0b70633e'/>
<id>20c315ebabc5a63b0bb169ddd60455ee0b70633e</id>
<content type='text'>
commit 446f666da9f019ce2ffd03800995487e79a91462 upstream.

USBDEVFS_URB_ISO_ASAP must be accepted only for ISO endpoints.
Improve sanity checking.

Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 446f666da9f019ce2ffd03800995487e79a91462 upstream.

USBDEVFS_URB_ISO_ASAP must be accepted only for ISO endpoints.
Improve sanity checking.

Reported-by: Andrey Konovalov &lt;andreyknvl@google.com&gt;
Signed-off-by: Oliver Neukum &lt;oneukum@suse.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: devio: Prevent integer overflow in proc_do_submiturb()</title>
<updated>2017-12-09T21:01:57+00:00</updated>
<author>
<name>Dan Carpenter</name>
<email>dan.carpenter@oracle.com</email>
</author>
<published>2017-09-22T20:43:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=545c10375330c9212227a6a7efd84f49ccd6c9b2'/>
<id>545c10375330c9212227a6a7efd84f49ccd6c9b2</id>
<content type='text'>
commit 57999d1107c1e60c2ca7088f2ac0f819e2f554b3 upstream.

There used to be an integer overflow check in proc_do_submiturb() but
we removed it.  It turns out that it's still required.  The
uurb-&gt;buffer_length variable is a signed integer and it's controlled by
the user.  It can lead to an integer overflow when we do:

	num_sgs = DIV_ROUND_UP(uurb-&gt;buffer_length, USB_SG_SIZE);

If we strip away the macro then that line looks like this:

	num_sgs = (uurb-&gt;buffer_length + USB_SG_SIZE - 1) / USB_SG_SIZE;
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It's the first addition which can overflow.

Fixes: 1129d270cbfb ("USB: Increase usbfs transfer limit")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 57999d1107c1e60c2ca7088f2ac0f819e2f554b3 upstream.

There used to be an integer overflow check in proc_do_submiturb() but
we removed it.  It turns out that it's still required.  The
uurb-&gt;buffer_length variable is a signed integer and it's controlled by
the user.  It can lead to an integer overflow when we do:

	num_sgs = DIV_ROUND_UP(uurb-&gt;buffer_length, USB_SG_SIZE);

If we strip away the macro then that line looks like this:

	num_sgs = (uurb-&gt;buffer_length + USB_SG_SIZE - 1) / USB_SG_SIZE;
                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
It's the first addition which can overflow.

Fixes: 1129d270cbfb ("USB: Increase usbfs transfer limit")
Signed-off-by: Dan Carpenter &lt;dan.carpenter@oracle.com&gt;
Acked-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: Increase usbfs transfer limit</title>
<updated>2017-12-09T21:01:57+00:00</updated>
<author>
<name>Mateusz Berezecki</name>
<email>mateuszb@fastmail.fm</email>
</author>
<published>2016-12-21T17:19:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d6ab871c432dbb30d8a186347f4d9ebd22041b6a'/>
<id>d6ab871c432dbb30d8a186347f4d9ebd22041b6a</id>
<content type='text'>
commit 1129d270cbfbb7e2b1ec3dede4a13930bdd10e41 upstream.

Promote a variable keeping track of USB transfer memory usage to a
wider data type and allow for higher bandwidth transfers from a large
number of USB devices connected to a single host.

Signed-off-by: Mateusz Berezecki &lt;mateuszb@fastmail.fm&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 1129d270cbfbb7e2b1ec3dede4a13930bdd10e41 upstream.

Promote a variable keeping track of USB transfer memory usage to a
wider data type and allow for higher bandwidth transfers from a large
number of USB devices connected to a single host.

Signed-off-by: Mateusz Berezecki &lt;mateuszb@fastmail.fm&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
</div>
</content>
</entry>
<entry>
<title>USB: usbfs: compute urb-&gt;actual_length for isochronous</title>
<updated>2017-11-21T08:23:29+00:00</updated>
<author>
<name>Alan Stern</name>
<email>stern@rowland.harvard.edu</email>
</author>
<published>2017-11-08T17:23:17+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=87ff414178cb2fc5ab30b636a3505efe248f6882'/>
<id>87ff414178cb2fc5ab30b636a3505efe248f6882</id>
<content type='text'>
commit 2ef47001b3ee3ded579b7532ebdcf8680e4d8c54 upstream.

The USB kerneldoc says that the actual_length field "is read in
non-iso completion functions", but the usbfs driver uses it for all
URB types in processcompl().  Since not all of the host controller
drivers set actual_length for isochronous URBs, programs using usbfs
with some host controllers don't work properly.  For example, Minas
reports that a USB camera controlled by libusb doesn't work properly
with a dwc2 controller.

It doesn't seem worthwhile to change the HCDs and the documentation,
since the in-kernel USB class drivers evidently don't rely on
actual_length for isochronous transfers.  The easiest solution is for
usbfs to calculate the actual_length value for itself, by adding up
the lengths of the individual packets in an isochronous transfer.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Minas Harutyunyan &lt;Minas.Harutyunyan@synopsys.com&gt;
Reported-and-tested-by: wlf &lt;wulf@rock-chips.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 2ef47001b3ee3ded579b7532ebdcf8680e4d8c54 upstream.

The USB kerneldoc says that the actual_length field "is read in
non-iso completion functions", but the usbfs driver uses it for all
URB types in processcompl().  Since not all of the host controller
drivers set actual_length for isochronous URBs, programs using usbfs
with some host controllers don't work properly.  For example, Minas
reports that a USB camera controlled by libusb doesn't work properly
with a dwc2 controller.

It doesn't seem worthwhile to change the HCDs and the documentation,
since the in-kernel USB class drivers evidently don't rely on
actual_length for isochronous transfers.  The easiest solution is for
usbfs to calculate the actual_length value for itself, by adding up
the lengths of the individual packets in an isochronous transfer.

Signed-off-by: Alan Stern &lt;stern@rowland.harvard.edu&gt;
CC: Minas Harutyunyan &lt;Minas.Harutyunyan@synopsys.com&gt;
Reported-and-tested-by: wlf &lt;wulf@rock-chips.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;

</pre>
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