linux-stable/drivers/vhost
Zha Bin 7fbe078c37 vhost/vsock: fix vhost vsock cid hashing inconsistent
The vsock core only supports 32bit CID, but the Virtio-vsock spec define
CID (dst_cid and src_cid) as u64 and the upper 32bits is reserved as
zero. This inconsistency causes one bug in vhost vsock driver. The
scenarios is:

  0. A hash table (vhost_vsock_hash) is used to map an CID to a vsock
  object. And hash_min() is used to compute the hash key. hash_min() is
  defined as:
  (sizeof(val) <= 4 ? hash_32(val, bits) : hash_long(val, bits)).
  That means the hash algorithm has dependency on the size of macro
  argument 'val'.
  0. In function vhost_vsock_set_cid(), a 64bit CID is passed to
  hash_min() to compute the hash key when inserting a vsock object into
  the hash table.
  0. In function vhost_vsock_get(), a 32bit CID is passed to hash_min()
  to compute the hash key when looking up a vsock for an CID.

Because the different size of the CID, hash_min() returns different hash
key, thus fails to look up the vsock object for an CID.

To fix this bug, we keep CID as u64 in the IOCTLs and virtio message
headers, but explicitly convert u64 to u32 when deal with the hash table
and vsock core.

Fixes: 834e772c8d ("vhost/vsock: fix use-after-free in network stack callers")
Link: https://github.com/stefanha/virtio/blob/vsock/trunk/content.tex
Signed-off-by: Zha Bin <zhabin@linux.alibaba.com>
Reviewed-by: Liu Jiang <gerry@linux.alibaba.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-11 17:48:11 -08:00
..
Kconfig vhost: allow vhost-scsi driver to be built-in 2018-08-22 01:01:32 +03:00
Kconfig.vringh vhost: split out vringh Kconfig 2016-08-02 16:54:28 +03:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
net.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-12-27 13:04:52 -08:00
scsi.c virtio, vhost: features, fixes, cleanups 2019-01-02 18:54:45 -08:00
test.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
test.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
vhost.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
vhost.h vhost: switch to use new message format 2018-08-06 10:41:04 -07:00
vringh.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
vsock.c vhost/vsock: fix vhost vsock cid hashing inconsistent 2019-01-11 17:48:11 -08:00