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authorJohan Hovold <johan@kernel.org>2019-10-09 19:09:42 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-10-10 12:41:18 +0200
commitbed5ef230943863b9abf5eae226a20fad9a8ff71 (patch)
tree5b6beb207aed9dc04a15c193f21da5e61d8c6c73
parent623170ff59710474d2db3dfb0ebb7577f44abd33 (diff)
downloadlinux-bed5ef230943863b9abf5eae226a20fad9a8ff71.tar.bz2
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>
-rw-r--r--drivers/usb/usb-skeleton.c7
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);