linux.git/net/tipc, branch v4.19.145

tipc: fix shutdown() of connectionless socket

2020-09-12T11:40:22+00:00

[ Upstream commit 2a63866c8b51a3f72cea388dfac259d0e14c4ba6 ]

syzbot is reporting hung task at nbd_ioctl() [1], for there are two
problems regarding TIPC's connectionless socket's shutdown() operation.

----------
#include 
#include 
#include 
#include 
#include 

int main(int argc, char *argv[])
{
        const int fd = open("/dev/nbd0", 3);
        alarm(5);
        ioctl(fd, NBD_SET_SOCK, socket(PF_TIPC, SOCK_DGRAM, 0));
        ioctl(fd, NBD_DO_IT, 0); /* To be interrupted by SIGALRM. */
        return 0;
}
----------

One problem is that wait_for_completion() from flush_workqueue() from
nbd_start_device_ioctl() from nbd_ioctl() cannot be completed when
nbd_start_device_ioctl() received a signal at wait_event_interruptible(),
for tipc_shutdown() from kernel_sock_shutdown(SHUT_RDWR) from
nbd_mark_nsock_dead() from sock_shutdown() from nbd_start_device_ioctl()
is failing to wake up a WQ thread sleeping at wait_woken() from
tipc_wait_for_rcvmsg() from sock_recvmsg() from sock_xmit() from
nbd_read_stat() from recv_work() scheduled by nbd_start_device() from
nbd_start_device_ioctl(). Fix this problem by always invoking
sk->sk_state_change() (like inet_shutdown() does) when tipc_shutdown() is
called.

The other problem is that tipc_wait_for_rcvmsg() cannot return when
tipc_shutdown() is called, for tipc_shutdown() sets sk->sk_shutdown to
SEND_SHUTDOWN (despite "how" is SHUT_RDWR) while tipc_wait_for_rcvmsg()
needs sk->sk_shutdown set to RCV_SHUTDOWN or SHUTDOWN_MASK. Fix this
problem by setting sk->sk_shutdown to SHUTDOWN_MASK (like inet_shutdown()
does) when the socket is connectionless.

[1] https://syzkaller.appspot.com/bug?id=3fe51d307c1f0a845485cf1798aa059d12bf18b2

Reported-by: syzbot 
Signed-off-by: Tetsuo Handa 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tipc: fix uninit skb->data in tipc_nl_compat_dumpit()

2020-09-03T09:24:17+00:00

[ Upstream commit 47733f9daf4fe4f7e0eb9e273f21ad3a19130487 ]

__tipc_nl_compat_dumpit() has two callers, and it expects them to
pass a valid nlmsghdr via arg->data. This header is artificial and
crafted just for __tipc_nl_compat_dumpit().

tipc_nl_compat_publ_dump() does so by putting a genlmsghdr as well
as some nested attribute, TIPC_NLA_SOCK. But the other caller
tipc_nl_compat_dumpit() does not, this leaves arg->data uninitialized
on this call path.

Fix this by just adding a similar nlmsghdr without any payload in
tipc_nl_compat_dumpit().

This bug exists since day 1, but the recent commit 6ea67769ff33
("net: tipc: prepare attrs in __tipc_nl_compat_dumpit()") makes it
easier to appear.

Reported-and-tested-by: syzbot+0e7181deafa7e0b79923@syzkaller.appspotmail.com
Fixes: d0796d1ef63d ("tipc: convert legacy nl bearer dump to nl compat")
Cc: Jon Maloy 
Cc: Ying Xue 
Cc: Richard Alpe 
Signed-off-by: Cong Wang 
Acked-by: Ying Xue 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tipc: clean up skb list lock handling on send path

2020-07-29T08:16:47+00:00

commit e654f9f53b45fde3fcc8051830b212c7a8f36148 upstream.

The policy for handling the skb list locks on the send and receive paths
is simple.

- On the send path we never need to grab the lock on the 'xmitq' list
  when the destination is an exernal node.

- On the receive path we always need to grab the lock on the 'inputq'
  list, irrespective of source node.

However, when transmitting node local messages those will eventually
end up on the receive path of a local socket, meaning that the argument
'xmitq' in tipc_node_xmit() will become the 'ínputq' argument in  the
function tipc_sk_rcv(). This has been handled by always initializing
the spinlock of the 'xmitq' list at message creation, just in case it
may end up on the receive path later, and despite knowing that the lock
in most cases never will be used.

This approach is inaccurate and confusing, and has also concealed the
fact that the stated 'no lock grabbing' policy for the send path is
violated in some cases.

We now clean up this by never initializing the lock at message creation,
instead doing this at the moment we find that the message actually will
enter the receive path. At the same time we fix the four locations
where we incorrectly access the spinlock on the send/error path.

This patch also reverts commit d12cffe9329f ("tipc: ensure head->lock
is initialised") which has now become redundant.

CC: Eric Dumazet 
Reported-by: Chris Packham 
Acked-by: Ying Xue 
Signed-off-by: Jon Maloy 
Reviewed-by: Xin Long 
Signed-off-by: David S. Miller 
[acj: backport v4.19 -stable
- adjust context
- skipped the hunk modifying non-existent function tipc_mcast_send_sync
- additional comment ]
Signed-off-by: Aviraj CJ 
Signed-off-by: Greg Kroah-Hartman

tipc: fix partial topology connection closure

2020-05-14T05:57:18+00:00

[ Upstream commit 980d69276f3048af43a045be2925dacfb898a7be ]

When an application connects to the TIPC topology server and subscribes
to some services, a new connection is created along with some objects -
'tipc_subscription' to store related data correspondingly...
However, there is one omission in the connection handling that when the
connection or application is orderly shutdown (e.g. via SIGQUIT, etc.),
the connection is not closed in kernel, the 'tipc_subscription' objects
are not freed too.
This results in:
- The maximum number of subscriptions (65535) will be reached soon, new
subscriptions will be rejected;
- TIPC module cannot be removed (unless the objects  are somehow forced
to release first);

The commit fixes the issue by closing the connection if the 'recvmsg()'
returns '0' i.e. when the peer is shutdown gracefully. It also includes
the other unexpected cases.

Acked-by: Jon Maloy 
Acked-by: Ying Xue 
Signed-off-by: Tuong Lien 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: ipv6_stub: use ip6_dst_lookup_flow instead of ip6_dst_lookup

2020-04-29T14:31:17+00:00

commit 6c8991f41546c3c472503dff1ea9daaddf9331c2 upstream.

ipv6_stub uses the ip6_dst_lookup function to allow other modules to
perform IPv6 lookups. However, this function skips the XFRM layer
entirely.

All users of ipv6_stub->ip6_dst_lookup use ip_route_output_flow (via the
ip_route_output_key and ip_route_output helpers) for their IPv4 lookups,
which calls xfrm_lookup_route(). This patch fixes this inconsistent
behavior by switching the stub to ip6_dst_lookup_flow, which also calls
xfrm_lookup_route().

This requires some changes in all the callers, as these two functions
take different arguments and have different return types.

Fixes: 5f81bd2e5d80 ("ipv6: export a stub for IPv6 symbols used by vxlan")
Reported-by: Xiumei Mu 
Signed-off-by: Sabrina Dubroca 
Signed-off-by: David S. Miller 
[bwh: Backported to 4.19:
 - Drop change in lwt_bpf.c
 - Delete now-unused "ret" in mlx5e_route_lookup_ipv6()
 - Initialise "out_dev" in mlx5e_create_encap_header_ipv6() to avoid
   introducing a spurious "may be used uninitialised" warning
 - Adjust filenames, context, indentation]
Signed-off-by: Ben Hutchings 
Signed-off-by: Sasha Levin

tipc: add missing attribute validation for MTU property

2020-03-18T06:14:18+00:00

[ Upstream commit 213320a67962ff6e7b83b704d55cbebc341426db ]

Add missing attribute validation for TIPC_NLA_PROP_MTU
to the netlink policy.

Fixes: 901271e0403a ("tipc: implement configuration of UDP media MTU")
Signed-off-by: Jakub Kicinski 
Signed-off-by: Jakub Kicinski 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tipc: reduce risk of wakeup queue starvation

2020-01-27T13:51:02+00:00

[ Upstream commit 7c5b42055964f587e55bd87ef334c3a27e95d144 ]

In commit 365ad353c256 ("tipc: reduce risk of user starvation during
link congestion") we allowed senders to add exactly one list of extra
buffers to the link backlog queues during link congestion (aka
"oversubscription"). However, the criteria for when to stop adding
wakeup messages to the input queue when the overload abates is
inaccurate, and may cause starvation problems during very high load.

Currently, we stop adding wakeup messages after 10 total failed attempts
where we find that there is no space left in the backlog queue for a
certain importance level. The counter for this is accumulated across all
levels, which may lead the algorithm to leave the loop prematurely,
although there may still be plenty of space available at some levels.
The result is sometimes that messages near the wakeup queue tail are not
added to the input queue as they should be.

We now introduce a more exact algorithm, where we keep adding wakeup
messages to a level as long as the backlog queue has free slots for
the corresponding level, and stop at the moment there are no more such
slots or when there are no more wakeup messages to dequeue.

Fixes: 365ad35 ("tipc: reduce risk of user starvation during link congestion")
Reported-by: Tung Nguyen 
Acked-by: Ying Xue 
Signed-off-by: Jon Maloy 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tipc: set sysctl_tipc_rmem and named_timeout right range

2020-01-27T13:50:39+00:00

[ Upstream commit 4bcd4ec1017205644a2697bccbc3b5143f522f5f ]

We find that sysctl_tipc_rmem and named_timeout do not have the right minimum
setting. sysctl_tipc_rmem should be larger than zero, like sysctl_tcp_rmem.
And named_timeout as a timeout setting should be not less than zero.

Fixes: cc79dd1ba9c10 ("tipc: change socket buffer overflow control to respect sk_rcvbuf")
Fixes: a5325ae5b8bff ("tipc: add name distributor resiliency queue")
Signed-off-by: Jie Liu 
Reported-by: Qiang Ning 
Reviewed-by: Zhiqiang Liu 
Reviewed-by: Miaohe Lin 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tipc: tipc clang warning

2020-01-27T13:50:33+00:00

[ Upstream commit 737889efe9713a0f20a75fd0de952841d9275e6b ]

When checking the code with clang -Wsometimes-uninitialized we get the
following warning:

if (!tipc_link_is_establishing(l)) {
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/tipc/node.c:847:46: note: uninitialized use occurs here
      tipc_bearer_xmit(n->net, bearer_id, &xmitq, maddr);

net/tipc/node.c:831:2: note: remove the 'if' if its condition is always
true
if (!tipc_link_is_establishing(l)) {
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/tipc/node.c:821:31: note: initialize the variable 'maddr' to silence
this warning
struct tipc_media_addr *maddr;

We fix this by initializing 'maddr' to NULL. For the matter of clarity,
we also test if 'xmitq' is non-empty before we use it and 'maddr'
further down in the  function. It will never happen that 'xmitq' is non-
empty at the same time as 'maddr' is NULL, so this is a sufficient test.

Fixes: 598411d70f85 ("tipc: make resetting of links non-atomic")
Reported-by: Nathan Chancellor 
Signed-off-by: Jon Maloy 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin

tipc: eliminate message disordering during binding table update

2020-01-27T13:50:00+00:00

[ Upstream commit 988f3f1603d4650409db5334355cbf7b13ef50c3 ]

We have seen the following race scenario:
1) named_distribute() builds a "bulk" message, containing a PUBLISH
   item for a certain publication. This is based on the contents of
   the binding tables's 'cluster_scope' list.
2) tipc_named_withdraw() removes the same publication from the list,
   bulds a WITHDRAW message and distributes it to all cluster nodes.
3) tipc_named_node_up(), which was calling named_distribute(), sends
   out the bulk message built under 1)
4) The WITHDRAW message arrives at the just detected node, finds
   no corresponding publication, and is dropped.
5) The PUBLISH item arrives at the same node, is added to its binding
   table, and remains there forever.

This arrival disordering was earlier taken care of by the backlog queue,
originally added for a different purpose, which was removed in the
commit referred to below, but we now need a different solution.
In this commit, we replace the rcu lock protecting the 'cluster_scope'
list with a regular RW lock which comprises even the sending of the
bulk message. This both guarantees both the list integrity and the
message sending order. We will later add a commit which cleans up
this code further.

Note that this commit needs recently added commit d3092b2efca1 ("tipc:
fix unsafe rcu locking when accessing publication list") to apply
cleanly.

Fixes: 37922ea4a310 ("tipc: permit overlapping service ranges in name table")
Reported-by: Tuong Lien Tong 
Acked-by: Ying Xue 
Signed-off-by: Jon Maloy 
Signed-off-by: David S. Miller 
Signed-off-by: Sasha Levin