Merge tag 'rxrpc-fixes-20181008' of git://git.kernel.org/pub/scm/linux/kernel/git...

David Howells says:

====================
rxrpc: Fix packet reception code

Here are a set of patches that prepares for and fix problems in rxrpc's
package reception code.  There serious problems are:

 (A) There's a window between binding the socket and setting the data_ready
     hook in which packets can find their way into the UDP socket's receive
     queues.

 (B) The skb_recv_udp() will return an error (and clear the error state) if
     there was an error on the Tx side.  rxrpc doesn't handle this.

 (C) The rxrpc data_ready handler doesn't fully drain the UDP receive
     queue.

 (D) The rxrpc data_ready handler assumes it is called in a non-reentrant
 state.

The second patch fixes (A) - (C); the third patch renders (B) and (C)
non-issues by using the recap_rcv hook instead of data_ready - and the
final patch fixes (D).  That last is the most complex.

The preparatory patches are:

 (1) Fix some places that are doing things in the wrong net namespace.

 (2) Stop taking the rcu read lock as it's held by the IP input routine in
     the call chain.

 (3) Only end the Tx phase if *we* rotated the final packet out of the Tx
     buffer.

 (4) Don't assume that the call state won't change after dropping the
     call_state lock.

 (5) Only take receive window and MTU suze parameters from an ACK packet if
     it's the latest ACK packet.

 (6) Record connection-level abort information correctly.

 (7) Fix a trace line.

And then there are three main patches - note that these are mixed in with
the preparatory patches somewhat:

 (1) Fix the setup window (A), skb_recv_udp() error check (B) and packet
     drainage (C).

 (2) Switch to using the encap_rcv instead of data_ready to cut out the
     effects of the UDP read queues and get the packets delivered directly.

 (3) Add more locking into the various packet input paths to defend against
     re-entrance (D).
====================

Signed-off-by: David S. Miller <davem@davemloft.net>