linux/drivers/vhost
Stefano Garzarella f6bbf0010b vhost-vdpa: fix use-after-free of v->config_ctx
When the 'v->config_ctx' eventfd_ctx reference is released we didn't
set it to NULL. So if the same character device (e.g. /dev/vhost-vdpa-0)
is re-opened, the 'v->config_ctx' is invalid and calling again
vhost_vdpa_config_put() causes use-after-free issues like the
following refcount_t underflow:

    refcount_t: underflow; use-after-free.
    WARNING: CPU: 2 PID: 872 at lib/refcount.c:28 refcount_warn_saturate+0xae/0xf0
    RIP: 0010:refcount_warn_saturate+0xae/0xf0
    Call Trace:
     eventfd_ctx_put+0x5b/0x70
     vhost_vdpa_release+0xcd/0x150 [vhost_vdpa]
     __fput+0x8e/0x240
     ____fput+0xe/0x10
     task_work_run+0x66/0xa0
     exit_to_user_mode_prepare+0x118/0x120
     syscall_exit_to_user_mode+0x21/0x50
     ? __x64_sys_close+0x12/0x40
     do_syscall_64+0x45/0x50
     entry_SYSCALL_64_after_hwframe+0x44/0xae

Fixes: 776f395004 ("vhost_vdpa: Support config interrupt in vdpa")
Cc: lingshan.zhu@intel.com
Cc: stable@vger.kernel.org
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210311135257.109460-2-sgarzare@redhat.com
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Zhu Lingshan <lingshan.zhu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
2021-03-14 18:10:07 -04:00
..
iotlb.c vhost: Fix documentation 2020-09-24 05:54:36 -04:00
Kconfig vhost_vdpa: implement IRQ offloading in vhost_vdpa 2020-08-05 11:08:42 -04:00
Makefile vhost: introduce vDPA-based backend 2020-04-02 10:41:40 -04:00
net.c vhost_net: fix ubuf refcount incorrectly when sendmsg fails 2021-01-04 13:18:52 -08:00
scsi.c vhost scsi: alloc vhost_scsi with kvzalloc() to avoid delay 2021-02-23 07:52:56 -05:00
test.c tools/virtio: Add --reset 2020-06-22 12:34:21 -04:00
test.h tools/virtio: Add --reset 2020-06-22 12:34:21 -04:00
vdpa.c vhost-vdpa: fix use-after-free of v->config_ctx 2021-03-14 18:10:07 -04:00
vhost.c vhost: Fix vhost_vq_reset() 2021-03-14 18:06:33 -04:00
vhost.h vhost: add helper to check if a vq has been setup 2020-11-15 17:30:54 -05:00
vringh.c vhost: vringh: use krealloc_array() 2020-12-15 12:13:37 -08:00
vsock.c vhost/vsock: add IOTLB API support 2020-12-27 05:49:01 -05:00