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| author | Johan Hovold <johan@kernel.org> | 2019-10-09 20:09:42 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-10 13:41:18 +0300 |
| commit | bed5ef230943863b9abf5eae226a20fad9a8ff71 (patch) | |
| tree | 5b6beb207aed9dc04a15c193f21da5e61d8c6c73 /drivers | |
| parent | 623170ff59710474d2db3dfb0ebb7577f44abd33 (diff) | |
| download | linux-bed5ef230943863b9abf5eae226a20fad9a8ff71.tar.xz | |
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: 4212cd74ca6f ("USB: usb-skeleton.c: remove err() usage")
Fixes: 5c290a5e42c3 ("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>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/usb-skeleton.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/usb/usb-skeleton.c b/drivers/usb/usb-skeleton.c index 8001d6384c73..c2843fcfa52d 100644 --- a/drivers/usb/usb-skeleton.c +++ b/drivers/usb/usb-skeleton.c @@ -61,6 +61,7 @@ struct usb_skel { spinlock_t err_lock; /* lock for errors */ struct kref kref; struct mutex io_mutex; /* synchronize I/O with disconnect */ + unsigned long disconnected:1; wait_queue_head_t bulk_in_wait; /* to wait for an ongoing read */ }; #define to_skel_dev(d) container_of(d, struct usb_skel, kref) @@ -238,7 +239,7 @@ static ssize_t skel_read(struct file *file, char *buffer, size_t count, if (rv < 0) return rv; - if (!dev->interface) { /* disconnect() was called */ + if (dev->disconnected) { /* disconnect() was called */ rv = -ENODEV; goto exit; } @@ -420,7 +421,7 @@ static ssize_t skel_write(struct file *file, const char *user_buffer, /* this lock makes sure we don't submit URBs to gone devices */ mutex_lock(&dev->io_mutex); - if (!dev->interface) { /* disconnect() was called */ + if (dev->disconnected) { /* disconnect() was called */ mutex_unlock(&dev->io_mutex); retval = -ENODEV; goto error; @@ -571,7 +572,7 @@ static void skel_disconnect(struct usb_interface *interface) /* prevent more I/O from starting */ mutex_lock(&dev->io_mutex); - dev->interface = NULL; + dev->disconnected = 1; mutex_unlock(&dev->io_mutex); usb_kill_anchored_urbs(&dev->submitted); |