USB: usb-skeleton: fix NULL-deref on disconnect
The driver was using its struct usb_interface pointer as an inverted disconnected flag and was setting it to NULL before making sure all completion handlers had run. This could lead to NULL-pointer dereferences in the dev_err() statements in the completion handlers which relies on said pointer. Fix this by using a dedicated disconnected flag. Note that this is also addresses a NULL-pointer dereference at release() and a struct usb_interface reference leak introduced by a recent runtime PM fix, which depends on and should have been submitted together with this patch. Fixes:4212cd74ca
("USB: usb-skeleton.c: remove err() usage") Fixes:5c290a5e42
("USB: usb-skeleton: fix runtime PM after driver unbind") Cc: stable <stable@vger.kernel.org> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20191009170944.30057-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
committed by
Greg Kroah-Hartman
parent
623170ff59
commit
bed5ef2309
@ -61,6 +61,7 @@ struct usb_skel {
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spinlock_t err_lock; /* lock for errors */
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spinlock_t err_lock; /* lock for errors */
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struct kref kref;
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struct kref kref;
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struct mutex io_mutex; /* synchronize I/O with disconnect */
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struct mutex io_mutex; /* synchronize I/O with disconnect */
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unsigned long disconnected:1;
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wait_queue_head_t bulk_in_wait; /* to wait for an ongoing read */
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wait_queue_head_t bulk_in_wait; /* to wait for an ongoing read */
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};
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};
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#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
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#define to_skel_dev(d) container_of(d, struct usb_skel, kref)
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@ -238,7 +239,7 @@ static ssize_t skel_read(struct file *file, char *buffer, size_t count,
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if (rv < 0)
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if (rv < 0)
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return rv;
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return rv;
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if (!dev->interface) { /* disconnect() was called */
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if (dev->disconnected) { /* disconnect() was called */
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rv = -ENODEV;
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rv = -ENODEV;
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goto exit;
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goto exit;
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}
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}
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@ -420,7 +421,7 @@ static ssize_t skel_write(struct file *file, const char *user_buffer,
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/* this lock makes sure we don't submit URBs to gone devices */
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/* this lock makes sure we don't submit URBs to gone devices */
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mutex_lock(&dev->io_mutex);
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mutex_lock(&dev->io_mutex);
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if (!dev->interface) { /* disconnect() was called */
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if (dev->disconnected) { /* disconnect() was called */
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mutex_unlock(&dev->io_mutex);
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mutex_unlock(&dev->io_mutex);
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retval = -ENODEV;
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retval = -ENODEV;
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goto error;
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goto error;
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@ -571,7 +572,7 @@ static void skel_disconnect(struct usb_interface *interface)
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/* prevent more I/O from starting */
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/* prevent more I/O from starting */
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mutex_lock(&dev->io_mutex);
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mutex_lock(&dev->io_mutex);
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dev->interface = NULL;
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dev->disconnected = 1;
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mutex_unlock(&dev->io_mutex);
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mutex_unlock(&dev->io_mutex);
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usb_kill_anchored_urbs(&dev->submitted);
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usb_kill_anchored_urbs(&dev->submitted);
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