From: Andrea Parri (Microsoft) <[email protected]> Sent: Wednesday, November 18, 2020 6:37 AM > > When channel->device_obj is non-NULL, vmbus_onoffer_rescind() could > invoke put_device(), that will eventually release the device and free > the channel object (cf. vmbus_device_release()). However, a pointer > to the object is dereferenced again later to load the primary_channel. > The use-after-free can be avoided by noticing that this load/check is > redundant if device_obk is non-NULL: primary_channel must be NULL if > device_obj is non-NULL, cf. vmbus_add_channel_work(). > > Reported-by: Juan Vazquez <[email protected]> > Signed-off-by: Andrea Parri (Microsoft) <[email protected]> > --- > drivers/hv/channel_mgmt.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c > index 5bc5eef5da159..4072fd1f22146 100644 > --- a/drivers/hv/channel_mgmt.c > +++ b/drivers/hv/channel_mgmt.c > @@ -1116,8 +1116,7 @@ static void vmbus_onoffer_rescind(struct > vmbus_channel_message_header *hdr) > vmbus_device_unregister(channel->device_obj); > put_device(dev); > } > - } > - if (channel->primary_channel != NULL) { > + } else if (channel->primary_channel != NULL) { > /* > * Sub-channel is being rescinded. Following is the channel > * close sequence when initiated from the driveri (refer to > -- > 2.25.1
Taking into the account the separate comments from Wei Liu, Reviewed-by: Michael Kelley <[email protected]>
