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>
Now that there are no more data path users of vhost_vsock_lock, it can
be turned into a mutex. It's only used by .release() and in the
.ioctl() path.
Depends-on: <20181105103547.22018-1-stefanha@redhat.com>
Suggested-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
If the network stack calls .send_pkt()/.cancel_pkt() during .release(),
a struct vhost_vsock use-after-free is possible. This occurs because
.release() does not wait for other CPUs to stop using struct
vhost_vsock.
Switch to an RCU-enabled hashtable (indexed by guest CID) so that
.release() can wait for other CPUs by calling synchronize_rcu(). This
also eliminates vhost_vsock_lock acquisition in the data path so it
could have a positive effect on performance.
This is CVE-2018-14625 "kernel: use-after-free Read in vhost_transport_send_pkt".
Cc: stable@vger.kernel.org
Reported-and-tested-by: syzbot+bd391451452fb0b93039@syzkaller.appspotmail.com
Reported-by: syzbot+e3e074963495f92a89ed@syzkaller.appspotmail.com
Reported-by: syzbot+d5a0a170c5069658b141@syzkaller.appspotmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>
If a local process has closed a connected socket and hasn't received a
RST packet yet, then the socket remains in the table until a timeout
expires.
When a vhost_vsock instance is released with the timeout still pending,
the socket is never freed because vhost_vsock has already set the
SOCK_DONE flag.
Check if the close timer is pending and let it close the socket. This
prevents the race which can leak sockets.
Reported-by: Maximilian Riemensberger <riemensberger@cadami.net>
Cc: Graham Whaley <graham.whaley@gmail.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This cleans up the qemu fw cfg device driver.
On top of this, vmcore is dumped there on crash to
help debugging witH kASLR enabled.
Also included are some fixes in vhost.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
Pull fw_cfg, vhost updates from Michael Tsirkin:
"This cleans up the qemu fw cfg device driver.
On top of this, vmcore is dumped there on crash to help debugging
with kASLR enabled.
Also included are some fixes in vhost"
* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
vhost: add vsock compat ioctl
vhost: fix vhost ioctl signature to build with clang
fw_cfg: write vmcoreinfo details
crash: export paddr_vmcoreinfo_note()
fw_cfg: add DMA register
fw_cfg: add a public uapi header
fw_cfg: handle fw_cfg_read_blob() error
fw_cfg: remove inline from fw_cfg_read_blob()
fw_cfg: fix sparse warnings around FW_CFG_FILE_DIR read
fw_cfg: fix sparse warning reading FW_CFG_ID
fw_cfg: fix sparse warnings with fw_cfg_file
fw_cfg: fix sparse warnings in fw_cfg_sel_endianness()
ptr_ring: fix build
This will allow usage of vsock from 32-bit binaries on a 64-bit
kernel.
Signed-off-by: Sonny Rao <sonnyrao@chromium.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fixed a coding style issue.
Signed-off-by: Vaibhav Murkute <vaibhavmurkute88@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In commit ea5d404655 ("vhost: fix release path lockdep checks"),
Michael added a flag to check whether we should hold a lock in
vhost_dev_cleanup(), however, in commit 47283bef7e ("vhost: move
memory pointer to VQs"), RCU operations have been replaced by
mutex, we can remove the no-longer-used `locked' parameter now.
Signed-off-by: Caspar Zhang <jinli.zjl@alibaba-inc.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The vhost_vsock->guest_cid field is uninitialized when /dev/vhost-vsock
is opened until the VHOST_VSOCK_SET_GUEST_CID ioctl is called.
kvmalloc(..., GFP_KERNEL | __GFP_RETRY_MAYFAIL) does not zero memory.
All other vhost_vsock fields are initialized explicitly so just
initialize this field too.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
__GFP_REPEAT was designed to allow retry-but-eventually-fail semantic to
the page allocator. This has been true but only for allocations
requests larger than PAGE_ALLOC_COSTLY_ORDER. It has been always
ignored for smaller sizes. This is a bit unfortunate because there is
no way to express the same semantic for those requests and they are
considered too important to fail so they might end up looping in the
page allocator for ever, similarly to GFP_NOFAIL requests.
Now that the whole tree has been cleaned up and accidental or misled
usage of __GFP_REPEAT flag has been removed for !costly requests we can
give the original flag a better name and more importantly a more useful
semantic. Let's rename it to __GFP_RETRY_MAYFAIL which tells the user
that the allocator would try really hard but there is no promise of a
success. This will work independent of the order and overrides the
default allocator behavior. Page allocator users have several levels of
guarantee vs. cost options (take GFP_KERNEL as an example)
- GFP_KERNEL & ~__GFP_RECLAIM - optimistic allocation without _any_
attempt to free memory at all. The most light weight mode which even
doesn't kick the background reclaim. Should be used carefully because
it might deplete the memory and the next user might hit the more
aggressive reclaim
- GFP_KERNEL & ~__GFP_DIRECT_RECLAIM (or GFP_NOWAIT)- optimistic
allocation without any attempt to free memory from the current
context but can wake kswapd to reclaim memory if the zone is below
the low watermark. Can be used from either atomic contexts or when
the request is a performance optimization and there is another
fallback for a slow path.
- (GFP_KERNEL|__GFP_HIGH) & ~__GFP_DIRECT_RECLAIM (aka GFP_ATOMIC) -
non sleeping allocation with an expensive fallback so it can access
some portion of memory reserves. Usually used from interrupt/bh
context with an expensive slow path fallback.
- GFP_KERNEL - both background and direct reclaim are allowed and the
_default_ page allocator behavior is used. That means that !costly
allocation requests are basically nofail but there is no guarantee of
that behavior so failures have to be checked properly by callers
(e.g. OOM killer victim is allowed to fail currently).
- GFP_KERNEL | __GFP_NORETRY - overrides the default allocator behavior
and all allocation requests fail early rather than cause disruptive
reclaim (one round of reclaim in this implementation). The OOM killer
is not invoked.
- GFP_KERNEL | __GFP_RETRY_MAYFAIL - overrides the default allocator
behavior and all allocation requests try really hard. The request
will fail if the reclaim cannot make any progress. The OOM killer
won't be triggered.
- GFP_KERNEL | __GFP_NOFAIL - overrides the default allocator behavior
and all allocation requests will loop endlessly until they succeed.
This might be really dangerous especially for larger orders.
Existing users of __GFP_REPEAT are changed to __GFP_RETRY_MAYFAIL
because they already had their semantic. No new users are added.
__alloc_pages_slowpath is changed to bail out for __GFP_RETRY_MAYFAIL if
there is no progress and we have already passed the OOM point.
This means that all the reclaim opportunities have been exhausted except
the most disruptive one (the OOM killer) and a user defined fallback
behavior is more sensible than keep retrying in the page allocator.
[akpm@linux-foundation.org: fix arch/sparc/kernel/mdesc.c]
[mhocko@suse.com: semantic fix]
Link: http://lkml.kernel.org/r/20170626123847.GM11534@dhcp22.suse.cz
[mhocko@kernel.org: address other thing spotted by Vlastimil]
Link: http://lkml.kernel.org/r/20170626124233.GN11534@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20170623085345.11304-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alex Belits <alex.belits@cavium.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: David Daney <david.daney@cavium.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: NeilBrown <neilb@suse.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Vhost-vsock is a software device so there is no probe call that causes
the driver to register its misc char device node. This creates a
chicken and egg problem: userspace applications must open
/dev/vhost-vsock to use the driver but the file doesn't exist until the
kernel module has been loaded.
Use the devname modalias mechanism so that /dev/vhost-vsock is created
at boot. The vhost_vsock kernel module is automatically loaded when the
first application opens /dev/host-vsock.
Note that the "reserved for local use" range in
Documentation/admin-guide/devices.txt is incorrect. The userio driver
already occupies part of that range. I've updated the documentation
accordingly.
Cc: device@lanana.org
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
vhost code uses __GFP_REPEAT when allocating vhost_virtqueue resp.
vhost_vsock because it would really like to prefer kmalloc to the
vmalloc fallback - see 23cc5a991c ("vhost-net: extend device
allocation to vmalloc") for more context. Michael Tsirkin has also
noted:
"__GFP_REPEAT overhead is during allocation time. Using vmalloc means
all accesses are slowed down. Allocation is not on data path, accesses
are."
The similar applies to other vhost_kvzalloc users.
Let's teach kvmalloc_node to handle __GFP_REPEAT properly. There are
two things to be careful about. First we should prevent from the OOM
killer and so have to involve __GFP_NORETRY by default and secondly
override __GFP_REPEAT for !costly order requests as the __GFP_REPEAT is
ignored for !costly orders.
Supporting __GFP_REPEAT like semantic for !costly request is possible it
would require changes in the page allocator. This is out of scope of
this patch.
This patch shouldn't introduce any functional change.
Link: http://lkml.kernel.org/r/20170306103032.2540-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The virtio drivers deal with struct virtio_vsock_pkt. Add
virtio_transport_deliver_tap_pkt(pkt) for handing packets to the
vsockmon device.
We call virtio_transport_deliver_tap_pkt(pkt) from
net/vmw_vsock/virtio_transport.c and drivers/vhost/vsock.c instead of
common code. This is because the drivers may drop packets before
handing them to common code - we still want to capture them.
Signed-off-by: Gerard Garcia <ggarcia@deic.uab.cat>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
To allow canceling all packets of a connection.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Propagate the error when vhost_vq_init_access() fails and set
vq->private_data to NULL.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Multi vsocks may setup the same cid at the same time.
Signed-off-by: Gao feng <omarapazanadi@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
local_addr.svm_cid is host cid. We should check guest cid instead,
which is remote_addr.svm_cid. Otherwise we end up resetting all
connections to all guests.
Cc: stable@vger.kernel.org [4.8+]
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Peng Tao <bergwolf@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stash the packet length in a local variable before handing over
ownership of the packet to virtio_transport_recv_pkt() or
virtio_transport_free_pkt().
This patch solves the use-after-free since pkt is no longer guaranteed
to be alive.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
VM sockets vhost transport implementation. This driver runs on the
host.
Signed-off-by: Asias He <asias@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Zha Bin