linux-stable.git/drivers/vhost/net.c, branch linux-3.17.y

vhost-net: don't open-code kvfree

2014-06-23T06:22:48+00:00

Commit 23cc5a991c ("vhost-net: extend device allocation to vmalloc")
added another open-coded version of kvfree (which is available since
v3.15-rc5), nuke it.

Signed-off-by: Romain Francoise 
Signed-off-by: Michael S. Tsirkin

vhost: move memory pointer to VQs

2014-06-09T13:21:07+00:00

commit 2ae76693b8bcabf370b981cd00c36cd41d33fabc
    vhost: replace rcu with mutex
replaced rcu sync for memory accesses with VQ mutex locl/unlock.
This is correct since all accesses are under VQ mutex, but incomplete:
we still do useless rcu lock/unlock operations, someone might copy this
code into some other context where this won't be right.
This use of RCU is also non standard and hard to understand.
Let's copy the pointer to each VQ structure, this way
the access rules become straight-forward, and there's
no need for RCU anymore.

Reported-by: Eric Dumazet 
Signed-off-by: Michael S. Tsirkin

vhost: move acked_features to VQs

2014-06-09T13:21:06+00:00

Refactor code to make sure features are only accessed
under VQ mutex. This makes everything simpler, no need
for RCU here anymore.

Signed-off-by: Michael S. Tsirkin

vhost-net: extend device allocation to vmalloc

2014-06-09T13:21:05+00:00

Michael Mueller provided a patch to reduce the size of
vhost-net structure as some allocations could fail under
memory pressure/fragmentation. We are still left with
high order allocations though.

This patch is handling the problem at the core level, allowing
vhost structures to use vmalloc() if kmalloc() failed.

As vmalloc() adds overhead on a critical network path, add __GFP_REPEAT
to kzalloc() flags to do this fallback only when really needed.

People are still looking at cleaner ways to handle the problem
at the API level, probably passing in multiple iovecs.
This hack seems consistent with approaches
taken since then by drivers/vhost/scsi.c and net/core/dev.c

Based on patch by Romain Francoise.

Cc: Michael Mueller 
Signed-off-by: Romain Francoise 
Acked-by: Michael S. Tsirkin

vhost: don't open-code sockfd_put()

2014-04-02T03:19:10+00:00

Signed-off-by: Al Viro

vhost: validate vhost_get_vq_desc return value

2014-03-28T20:10:35+00:00

vhost fails to validate negative error code
from vhost_get_vq_desc causing
a crash: we are using -EFAULT which is 0xfffffff2
as vector size, which exceeds the allocated size.

The code in question was introduced in commit
8dd014adfea6f173c1ef6378f7e5e7924866c923
    vhost-net: mergeable buffers support

CVE-2014-0055

Signed-off-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller

vhost: fix total length when packets are too short

2014-03-28T20:07:31+00:00

When mergeable buffers are disabled, and the
incoming packet is too large for the rx buffer,
get_rx_bufs returns success.

This was intentional in order for make recvmsg
truncate the packet and then handle_rx would
detect err != sock_len and drop it.

Unfortunately we pass the original sock_len to
recvmsg - which means we use parts of iov not fully
validated.

Fix this up by detecting this overrun and doing packet drop
immediately.

CVE-2014-0077

Signed-off-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller

vhost: fix a theoretical race in device cleanup

2014-02-13T23:47:30+00:00

vhost_zerocopy_callback accesses VQ right after it drops a ubuf
reference.  In theory, this could race with device removal which waits
on the ubuf kref, and crash on use after free.

Do all accesses within rcu read side critical section, and synchronize
on release.

Since callbacks are always invoked from bh, synchronize_rcu_bh seems
enough and will help release complete a bit faster.

Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang 
Signed-off-by: David S. Miller

vhost: fix ref cnt checking deadlock

2014-02-13T23:47:30+00:00

vhost checked the counter within the refcnt before decrementing.  It
really wanted to know that it is the one that has the last reference, as
a way to batch freeing resources a bit more efficiently.

Note: we only let refcount go to 0 on device release.

This works well but we now access the ref counter twice so there's a
race: all users might see a high count and decide to defer freeing
resources.
In the end no one initiates freeing resources until the last reference
is gone (which is on VM shotdown so might happen after a looooong time).

Let's do what we probably should have done straight away:
switch from kref to plain atomic, documenting the
semantics, return the refcount value atomically after decrement,
then use that to avoid the deadlock.

Reported-by: Qin Chuanyu 
Signed-off-by: Michael S. Tsirkin 
Acked-by: Jason Wang 
Signed-off-by: David S. Miller

vhost: remove the dead branch

2013-12-06T20:22:05+00:00

Since vhost_dev_init() forever return 0, some branches are never run,
therefore need to be removed.

Signed-off-by: Zhi Yong Wu 
Acked-by: Michael S. Tsirkin 
Signed-off-by: David S. Miller