Commit Graph

116 Commits

Author SHA1 Message Date
David Howells f3441d4125 rxrpc: Copy client call parameters into rxrpc_call earlier
Copy client call parameters into rxrpc_call earlier so that that can be
used to convey them to the connection code - which can then be offloaded to
the I/O thread.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:41 +00:00
David Howells 15f661dc95 rxrpc: Implement a mechanism to send an event notification to a call
Provide a means by which an event notification can be sent to a call such
that the I/O thread can process it rather than it being done in a separate
workqueue.  This will allow a lot of locking to be removed.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:41 +00:00
David Howells 4041a8ff65 rxrpc: Remove call->input_lock
Remove call->input_lock as it was only necessary to serialise access to the
state stored in the rxrpc_call struct by simultaneous softirq handlers
presenting received packets.  They now dump the packets in a queue and a
single process-context handler now processes them.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:40 +00:00
David Howells 446b3e1452 rxrpc: Move packet reception processing into I/O thread
Split the packet input handler to make the softirq side just dump the
received packet into the local endpoint receive queue and then call the
remainder of the input function from the I/O thread.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:40 +00:00
David Howells 3feda9d69c rxrpc: Don't hold a ref for call timer or workqueue
Currently, rxrpc gives the call timer a ref on the call when it starts it
and this is passed along to the workqueue by the timer expiration function.
The problem comes when queue_work() fails (ie. the work item is already
queued): the timer routine must put the ref - but this may cause the
cleanup code to run.

This has the unfortunate effect that the cleanup code may then be run in
softirq context - which means that any spinlocks it might need to touch
have to be guarded to disable softirqs (ie. they need a "_bh" suffix).

Fix this by:

 (1) Don't give a ref to the timer.

 (2) Making the expiration function not do anything if the refcount is 0.
     Note that this is more of an optimisation.

 (3) Make sure that the cleanup routine waits for timer to complete.

However, this has a consequence that timer cannot give a ref to the work
item.  Therefore the following fixes are also necessary:

 (4) Don't give a ref to the work item.

 (5) Make the work item return asap if it sees the ref count is 0.

 (6) Make sure that the cleanup routine waits for the work item to
     complete.

Unfortunately, neither the timer nor the work item can simply get around
the problem by just using refcount_inc_not_zero() as the waits would still
have to be done, and there would still be the possibility of having to put
the ref in the expiration function.

Note the call work item is going to go away with the work being transferred
to the I/O thread, so the wait in (6) will become obsolete.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:39 +00:00
David Howells 9a36a6bc22 rxrpc: trace: Don't use __builtin_return_address for sk_buff tracing
In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the sk_buff tracepoint.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:39 +00:00
David Howells cb0fc0c972 rxrpc: trace: Don't use __builtin_return_address for rxrpc_call tracing
In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the rxrpc_call tracepoint

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:39 +00:00
David Howells 7fa25105b2 rxrpc: trace: Don't use __builtin_return_address for rxrpc_conn tracing
In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the rxrpc_conn tracepoint

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:39 +00:00
David Howells 47c810a798 rxrpc: trace: Don't use __builtin_return_address for rxrpc_peer tracing
In rxrpc tracing, use enums to generate lists of points of interest rather
than __builtin_return_address() for the rxrpc_peer tracepoint

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:38 +00:00
David Howells 2cc800863c rxrpc: Drop rxrpc_conn_parameters from rxrpc_connection and rxrpc_bundle
Remove the rxrpc_conn_parameters struct from the rxrpc_connection and
rxrpc_bundle structs and emplace the members directly.  These are going to
get filled in from the rxrpc_call struct in future.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:38 +00:00
David Howells e969c92ce5 rxrpc: Remove the [_k]net() debugging macros
Remove the _net() and knet() debugging macros in favour of tracepoints.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-12-01 13:36:38 +00:00
David Howells 1fc4fa2ac9 rxrpc: Fix congestion management
rxrpc has a problem in its congestion management in that it saves the
congestion window size (cwnd) from one call to another, but if this is 0 at
the time is saved, then the next call may not actually manage to ever
transmit anything.

To this end:

 (1) Don't save cwnd between calls, but rather reset back down to the
     initial cwnd and re-enter slow-start if data transmission is idle for
     more than an RTT.

 (2) Preserve ssthresh instead, as that is a handy estimate of pipe
     capacity.  Knowing roughly when to stop slow start and enter
     congestion avoidance can reduce the tendency to overshoot and drop
     larger amounts of packets when probing.

In future, cwind growth also needs to be constrained when the window isn't
being filled due to being application limited.

Reported-by: Simon Wilkinson <sxw@auristor.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells 6869ddb87d rxrpc: Remove the rxtx ring
The Rx/Tx ring is no longer used, so remove it.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells d57a3a1516 rxrpc: Save last ACK's SACK table rather than marking txbufs
Improve the tracking of which packets need to be transmitted by saving the
last ACK packet that we receive that has a populated soft-ACK table rather
than marking packets.  Then we can step through the soft-ACK table and look
at the packets we've transmitted beyond that to determine which packets we
might want to retransmit.

We also look at the highest serial number that has been acked to try and
guess which packets we've transmitted the peer is likely to have seen.  If
necessary, we send a ping to retrieve that number.

One downside that might be a problem is that we can't then compare the
previous acked/unacked state so easily in rxrpc_input_soft_acks() - which
is a potential problem for the slow-start algorithm.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells 4e76bd406d rxrpc: Remove call->lock
call->lock is no longer necessary, so remove it.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells a4ea4c4776 rxrpc: Don't use a ring buffer for call Tx queue
Change the way the Tx queueing works to make the following ends easier to
achieve:

 (1) The filling of packets, the encryption of packets and the transmission
     of packets can be handled in parallel by separate threads, rather than
     rxrpc_sendmsg() allocating, filling, encrypting and transmitting each
     packet before moving onto the next one.

 (2) Get rid of the fixed-size ring which sets a hard limit on the number
     of packets that can be retained in the ring.  This allows the number
     of packets to increase without having to allocate a very large ring or
     having variable-sized rings.

     [Note: the downside of this is that it's then less efficient to locate
     a packet for retransmission as we then have to step through a list and
     examine each buffer in the list.]

 (3) Allow the filler/encrypter to run ahead of the transmission window.

 (4) Make it easier to do zero copy UDP from the packet buffers.

 (5) Make it easier to do zero copy from userspace to the packet buffers -
     and thence to UDP (only if for unauthenticated connections).

To that end, the following changes are made:

 (1) Use the new rxrpc_txbuf struct instead of sk_buff for keeping packets
     to be transmitted in.  This allows them to be placed on multiple
     queues simultaneously.  An sk_buff isn't really necessary as it's
     never passed on to lower-level networking code.

 (2) Keep the transmissable packets in a linked list on the call struct
     rather than in a ring.  As a consequence, the annotation buffer isn't
     used either; rather a flag is set on the packet to indicate ackedness.

 (3) Use the RXRPC_CALL_TX_LAST flag to indicate that the last packet to be
     transmitted has been queued.  Add RXRPC_CALL_TX_ALL_ACKED to indicate
     that all packets up to and including the last got hard acked.

 (4) Wire headers are now stored in the txbuf rather than being concocted
     on the stack and they're stored immediately before the data, thereby
     allowing zerocopy of a single span.

 (5) Don't bother with instant-resend on transmission failure; rather,
     leave it for a timer or an ACK packet to trigger.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells 5d7edbc923 rxrpc: Get rid of the Rx ring
Get rid of the Rx ring and replace it with a pair of queues instead.  One
queue gets the packets that are in-sequence and are ready for processing by
recvmsg(); the other queue gets the out-of-sequence packets for addition to
the first queue as the holes get filled.

The annotation ring is removed and replaced with a SACK table.  The SACK
table has the bits set that correspond exactly to the sequence number of
the packet being acked.  The SACK ring is copied when an ACK packet is
being assembled and rotated so that the first ACK is in byte 0.

Flow control handling is altered so that packets that are moved to the
in-sequence queue are hard-ACK'd even before they're consumed - and then
the Rx window size in the ACK packet (rsize) is shrunk down to compensate
(even going to 0 if the window is full).

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells 530403d9ba rxrpc: Clean up ACK handling
Clean up the rxrpc_propose_ACK() function.  If deferred PING ACK proposal
is split out, it's only really needed for deferred DELAY ACKs.  All other
ACKs, bar terminal IDLE ACK are sent immediately.  The deferred IDLE ACK
submission can be handled by conversion of a DELAY ACK into an IDLE ACK if
there's nothing to be SACK'd.

Also, because there's a delay between an ACK being generated and being
transmitted, it's possible that other ACKs of the same type will be
generated during that interval.  Apart from the ACK time and the serial
number responded to, most of the ACK body, including window and SACK
parameters, are not filled out till the point of transmission - so we can
avoid generating a new ACK if there's one pending that will cover the SACK
data we need to convey.

Therefore, don't propose a new DELAY or IDLE ACK for a call if there's one
already pending.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells a11e6ff961 rxrpc: Remove call->tx_phase
Remove call->tx_phase as it's only ever set.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:28 +00:00
David Howells 334dfbfc5a rxrpc: Split call timer-expiration from call timer-set tracepoint
Split the tracepoint for call timer-set to separate out the call
timer-expiration event

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
2022-11-08 16:42:15 +00:00
David Howells b0f571ecd7 rxrpc: Fix locking in rxrpc's sendmsg
Fix three bugs in the rxrpc's sendmsg implementation:

 (1) rxrpc_new_client_call() should release the socket lock when returning
     an error from rxrpc_get_call_slot().

 (2) rxrpc_wait_for_tx_window_intr() will return without the call mutex
     held in the event that we're interrupted by a signal whilst waiting
     for tx space on the socket or relocking the call mutex afterwards.

     Fix this by: (a) moving the unlock/lock of the call mutex up to
     rxrpc_send_data() such that the lock is not held around all of
     rxrpc_wait_for_tx_window*() and (b) indicating to higher callers
     whether we're return with the lock dropped.  Note that this means
     recvmsg() will not block on this call whilst we're waiting.

 (3) After dropping and regaining the call mutex, rxrpc_send_data() needs
     to go and recheck the state of the tx_pending buffer and the
     tx_total_len check in case we raced with another sendmsg() on the same
     call.

Thinking on this some more, it might make sense to have different locks for
sendmsg() and recvmsg().  There's probably no need to make recvmsg() wait
for sendmsg().  It does mean that recvmsg() can return MSG_EOR indicating
that a call is dead before a sendmsg() to that call returns - but that can
currently happen anyway.

Without fix (2), something like the following can be induced:

	WARNING: bad unlock balance detected!
	5.16.0-rc6-syzkaller #0 Not tainted
	-------------------------------------
	syz-executor011/3597 is trying to release lock (&call->user_mutex) at:
	[<ffffffff885163a3>] rxrpc_do_sendmsg+0xc13/0x1350 net/rxrpc/sendmsg.c:748
	but there are no more locks to release!

	other info that might help us debug this:
	no locks held by syz-executor011/3597.
	...
	Call Trace:
	 <TASK>
	 __dump_stack lib/dump_stack.c:88 [inline]
	 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
	 print_unlock_imbalance_bug include/trace/events/lock.h:58 [inline]
	 __lock_release kernel/locking/lockdep.c:5306 [inline]
	 lock_release.cold+0x49/0x4e kernel/locking/lockdep.c:5657
	 __mutex_unlock_slowpath+0x99/0x5e0 kernel/locking/mutex.c:900
	 rxrpc_do_sendmsg+0xc13/0x1350 net/rxrpc/sendmsg.c:748
	 rxrpc_sendmsg+0x420/0x630 net/rxrpc/af_rxrpc.c:561
	 sock_sendmsg_nosec net/socket.c:704 [inline]
	 sock_sendmsg+0xcf/0x120 net/socket.c:724
	 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2409
	 ___sys_sendmsg+0xf3/0x170 net/socket.c:2463
	 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2492
	 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
	 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
	 entry_SYSCALL_64_after_hwframe+0x44/0xae

[Thanks to Hawkins Jiawei and Khalid Masum for their attempts to fix this]

Fixes: bc5e3a546d ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Reported-by: syzbot+7f0483225d0c94cb3441@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Tested-by: syzbot+7f0483225d0c94cb3441@syzkaller.appspotmail.com
cc: Hawkins Jiawei <yin31149@gmail.com>
cc: Khalid Masum <khalid.masum.92@gmail.com>
cc: Dan Carpenter <dan.carpenter@oracle.com>
cc: linux-afs@lists.infradead.org
Link: https://lore.kernel.org/r/166135894583.600315.7170979436768124075.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-08-25 12:39:40 -07:00
David Howells ad25f5cb39 rxrpc: Fix locking issue
There's a locking issue with the per-netns list of calls in rxrpc.  The
pieces of code that add and remove a call from the list use write_lock()
and the calls procfile uses read_lock() to access it.  However, the timer
callback function may trigger a removal by trying to queue a call for
processing and finding that it's already queued - at which point it has a
spare refcount that it has to do something with.  Unfortunately, if it puts
the call and this reduces the refcount to 0, the call will be removed from
the list.  Unfortunately, since the _bh variants of the locking functions
aren't used, this can deadlock.

================================
WARNING: inconsistent lock state
5.18.0-rc3-build4+ #10 Not tainted
--------------------------------
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
ksoftirqd/2/25 [HC0[0]:SC1[1]:HE1:SE0] takes:
ffff888107ac4038 (&rxnet->call_lock){+.?.}-{2:2}, at: rxrpc_put_call+0x103/0x14b
{SOFTIRQ-ON-W} state was registered at:
...
 Possible unsafe locking scenario:

       CPU0
       ----
  lock(&rxnet->call_lock);
  <Interrupt>
    lock(&rxnet->call_lock);

 *** DEADLOCK ***

1 lock held by ksoftirqd/2/25:
 #0: ffff8881008ffdb0 ((&call->timer)){+.-.}-{0:0}, at: call_timer_fn+0x5/0x23d

Changes
=======
ver #2)
 - Changed to using list_next_rcu() rather than rcu_dereference() directly.

Fixes: 17926a7932 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-22 21:03:01 +01:00
David Howells a05754295e rxrpc: Use refcount_t rather than atomic_t
Move to using refcount_t rather than atomic_t for refcounts in rxrpc.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-22 21:03:01 +01:00
David Howells 4a7f62f919 rxrpc: Fix call timer start racing with call destruction
The rxrpc_call struct has a timer used to handle various timed events
relating to a call.  This timer can get started from the packet input
routines that are run in softirq mode with just the RCU read lock held.
Unfortunately, because only the RCU read lock is held - and neither ref or
other lock is taken - the call can start getting destroyed at the same time
a packet comes in addressed to that call.  This causes the timer - which
was already stopped - to get restarted.  Later, the timer dispatch code may
then oops if the timer got deallocated first.

Fix this by trying to take a ref on the rxrpc_call struct and, if
successful, passing that ref along to the timer.  If the timer was already
running, the ref is discarded.

The timer completion routine can then pass the ref along to the call's work
item when it queues it.  If the timer or work item where already
queued/running, the extra ref is discarded.

Fixes: a158bdd324 ("rxrpc: Fix call timeouts")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Tested-by: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Link: http://lists.infradead.org/pipermail/linux-afs/2022-March/005073.html
Link: https://lore.kernel.org/r/164865115696.2943015.11097991776647323586.stgit@warthog.procyon.org.uk
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-03-31 12:25:25 +02:00
David Howells 7b5eab57ca rxrpc: Fix clearance of Tx/Rx ring when releasing a call
At the end of rxrpc_release_call(), rxrpc_cleanup_ring() is called to clear
the Rx/Tx skbuff ring, but this doesn't lock the ring whilst it's accessing
it.  Unfortunately, rxrpc_resend() might be trying to retransmit a packet
concurrently with this - and whilst it does lock the ring, this isn't
protection against rxrpc_cleanup_call().

Fix this by removing the call to rxrpc_cleanup_ring() from
rxrpc_release_call().  rxrpc_cleanup_ring() will be called again anyway
from rxrpc_cleanup_call().  The earlier call is just an optimisation to
recycle skbuffs more quickly.

Alternative solutions include rxrpc_release_call() could try to cancel the
work item or wait for it to complete or rxrpc_cleanup_ring() could lock
when accessing the ring (which would require a bh lock).

This can produce a report like the following:

  BUG: KASAN: use-after-free in rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372
  Read of size 4 at addr ffff888011606e04 by task kworker/0:0/5
  ...
  Workqueue: krxrpcd rxrpc_process_call
  Call Trace:
   ...
   kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413
   rxrpc_send_data_packet+0x19b4/0x1e70 net/rxrpc/output.c:372
   rxrpc_resend net/rxrpc/call_event.c:266 [inline]
   rxrpc_process_call+0x1634/0x1f60 net/rxrpc/call_event.c:412
   process_one_work+0x98d/0x15f0 kernel/workqueue.c:2275
   ...

  Allocated by task 2318:
   ...
   sock_alloc_send_pskb+0x793/0x920 net/core/sock.c:2348
   rxrpc_send_data+0xb51/0x2bf0 net/rxrpc/sendmsg.c:358
   rxrpc_do_sendmsg+0xc03/0x1350 net/rxrpc/sendmsg.c:744
   rxrpc_sendmsg+0x420/0x630 net/rxrpc/af_rxrpc.c:560
   ...

  Freed by task 2318:
   ...
   kfree_skb+0x140/0x3f0 net/core/skbuff.c:704
   rxrpc_free_skb+0x11d/0x150 net/rxrpc/skbuff.c:78
   rxrpc_cleanup_ring net/rxrpc/call_object.c:485 [inline]
   rxrpc_release_call+0x5dd/0x860 net/rxrpc/call_object.c:552
   rxrpc_release_calls_on_socket+0x21c/0x300 net/rxrpc/call_object.c:579
   rxrpc_release_sock net/rxrpc/af_rxrpc.c:885 [inline]
   rxrpc_release+0x263/0x5a0 net/rxrpc/af_rxrpc.c:916
   __sock_release+0xcd/0x280 net/socket.c:597
   ...

  The buggy address belongs to the object at ffff888011606dc0
   which belongs to the cache skbuff_head_cache of size 232

Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Reported-by: syzbot+174de899852504e4a74a@syzkaller.appspotmail.com
Reported-by: syzbot+3d1c772efafd3c38d007@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hillf Danton <hdanton@sina.com>
Link: https://lore.kernel.org/r/161234207610.653119.5287360098400436976.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2021-02-04 18:11:08 -08:00
Jakub Kicinski 9d49aea13f Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Small conflict around locking in rxrpc_process_event() -
channel_lock moved to bundle in next, while state lock
needs _bh() from net.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2020-10-08 15:44:50 -07:00
David Howells 2d914c1bf0 rxrpc: Fix accept on a connection that need securing
When a new incoming call arrives at an userspace rxrpc socket on a new
connection that has a security class set, the code currently pushes it onto
the accept queue to hold a ref on it for the socket.  This doesn't work,
however, as recvmsg() pops it off, notices that it's in the SERVER_SECURING
state and discards the ref.  This means that the call runs out of refs too
early and the kernel oopses.

By contrast, a kernel rxrpc socket manually pre-charges the incoming call
pool with calls that already have user call IDs assigned, so they are ref'd
by the call tree on the socket.

Change the mode of operation for userspace rxrpc server sockets to work
like this too.  Although this is a UAPI change, server sockets aren't
currently functional.

Fixes: 248f219cb8 ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-10-05 16:35:57 +01:00
David Howells b7a7d67408 rxrpc: Impose a maximum number of client calls
Impose a maximum on the number of client rxrpc calls that are allowed
simultaneously.  This will be in lieu of a maximum number of client
connections as this is easier to administed as, unlike connections, calls
aren't reusable (to be changed in a subsequent patch)..

This doesn't affect the limits on service calls and connections.

Signed-off-by: David Howells <dhowells@redhat.com>
2020-09-08 21:10:45 +01:00
David Howells 4700c4d80b rxrpc: Fix loss of RTT samples due to interposed ACK
The Rx protocol has a mechanism to help generate RTT samples that works by
a client transmitting a REQUESTED-type ACK when it receives a DATA packet
that has the REQUEST_ACK flag set.

The peer, however, may interpose other ACKs before transmitting the
REQUESTED-ACK, as can be seen in the following trace excerpt:

 rxrpc_tx_data: c=00000044 DATA d0b5ece8:00000001 00000001 q=00000001 fl=07
 rxrpc_rx_ack: c=00000044 00000001 PNG r=00000000 f=00000002 p=00000000 n=0
 rxrpc_rx_ack: c=00000044 00000002 REQ r=00000001 f=00000002 p=00000001 n=0
 ...

DATA packet 1 (q=xx) has REQUEST_ACK set (bit 1 of fl=xx).  The incoming
ping (labelled PNG) hard-acks the request DATA packet (f=xx exceeds the
sequence number of the DATA packet), causing it to be discarded from the Tx
ring.  The ACK that was requested (labelled REQ, r=xx references the serial
of the DATA packet) comes after the ping, but the sk_buff holding the
timestamp has gone and the RTT sample is lost.

This is particularly noticeable on RPC calls used to probe the service
offered by the peer.  A lot of peers end up with an unknown RTT because we
only ever sent a single RPC.  This confuses the server rotation algorithm.

Fix this by caching the information about the outgoing packet in RTT
calculations in the rxrpc_call struct rather than looking in the Tx ring.

A four-deep buffer is maintained and both REQUEST_ACK-flagged DATA and
PING-ACK transmissions are recorded in there.  When the appropriate
response ACK is received, the buffer is checked for a match and, if found,
an RTT sample is recorded.

If a received ACK refers to a packet with a later serial number than an
entry in the cache, that entry is presumed lost and the entry is made
available to record a new transmission.

ACKs types other than REQUESTED-type and PING-type cause any matching
sample to be cancelled as they don't necessarily represent a useful
measurement.

If there's no space in the buffer on ping/data transmission, the sample
base is discarded.

Fixes: 50235c4b5a ("rxrpc: Obtain RTT data by requesting ACKs on DATA packets")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-08-20 17:59:27 +01:00
David Howells 65550098c1 rxrpc: Fix race between recvmsg and sendmsg on immediate call failure
There's a race between rxrpc_sendmsg setting up a call, but then failing to
send anything on it due to an error, and recvmsg() seeing the call
completion occur and trying to return the state to the user.

An assertion fails in rxrpc_recvmsg() because the call has already been
released from the socket and is about to be released again as recvmsg deals
with it.  (The recvmsg_q queue on the socket holds a ref, so there's no
problem with use-after-free.)

We also have to be careful not to end up reporting an error twice, in such
a way that both returns indicate to userspace that the user ID supplied
with the call is no longer in use - which could cause the client to
malfunction if it recycles the user ID fast enough.

Fix this by the following means:

 (1) When sendmsg() creates a call after the point that the call has been
     successfully added to the socket, don't return any errors through
     sendmsg(), but rather complete the call and let recvmsg() retrieve
     them.  Make sendmsg() return 0 at this point.  Further calls to
     sendmsg() for that call will fail with ESHUTDOWN.

     Note that at this point, we haven't send any packets yet, so the
     server doesn't yet know about the call.

 (2) If sendmsg() returns an error when it was expected to create a new
     call, it means that the user ID wasn't used.

 (3) Mark the call disconnected before marking it completed to prevent an
     oops in rxrpc_release_call().

 (4) recvmsg() will then retrieve the error and set MSG_EOR to indicate
     that the user ID is no longer known by the kernel.

An oops like the following is produced:

	kernel BUG at net/rxrpc/recvmsg.c:605!
	...
	RIP: 0010:rxrpc_recvmsg+0x256/0x5ae
	...
	Call Trace:
	 ? __init_waitqueue_head+0x2f/0x2f
	 ____sys_recvmsg+0x8a/0x148
	 ? import_iovec+0x69/0x9c
	 ? copy_msghdr_from_user+0x5c/0x86
	 ___sys_recvmsg+0x72/0xaa
	 ? __fget_files+0x22/0x57
	 ? __fget_light+0x46/0x51
	 ? fdget+0x9/0x1b
	 do_recvmmsg+0x15e/0x232
	 ? _raw_spin_unlock+0xa/0xb
	 ? vtime_delta+0xf/0x25
	 __x64_sys_recvmmsg+0x2c/0x2f
	 do_syscall_64+0x4c/0x78
	 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 357f5ef646 ("rxrpc: Call rxrpc_release_call() on error in rxrpc_new_client_call()")
Reported-by: syzbot+b54969381df354936d96@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-07-30 16:50:20 -07:00
David Howells e138aa7d32 rxrpc: Fix call interruptibility handling
Fix the interruptibility of kernel-initiated client calls so that they're
either only interruptible when they're waiting for a call slot to come
available or they're not interruptible at all.  Either way, they're not
interruptible during transmission.

This should help prevent StoreData calls from being interrupted when
writeback is in progress.  It doesn't, however, handle interruption during
the receive phase.

Userspace-initiated calls are still interruptable.  After the signal has
been handled, sendmsg() will return the amount of data copied out of the
buffer and userspace can perform another sendmsg() call to continue
transmission.

Fixes: bc5e3a546d ("rxrpc: Use MSG_WAITALL to tell sendmsg() to temporarily ignore signals")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-03-13 23:04:30 +00:00
David Howells 963485d436 rxrpc: Fix call RCU cleanup using non-bh-safe locks
rxrpc_rcu_destroy_call(), which is called as an RCU callback to clean up a
put call, calls rxrpc_put_connection() which, deep in its bowels, takes a
number of spinlocks in a non-BH-safe way, including rxrpc_conn_id_lock and
local->client_conns_lock.  RCU callbacks, however, are normally called from
softirq context, which can cause lockdep to notice the locking
inconsistency.

To get lockdep to detect this, it's necessary to have the connection
cleaned up on the put at the end of the last of its calls, though normally
the clean up is deferred.  This can be induced, however, by starting a call
on an AF_RXRPC socket and then closing the socket without reading the
reply.

Fix this by having rxrpc_rcu_destroy_call() punt the destruction to a
workqueue if in softirq-mode and defer the destruction to process context.

Note that another way to fix this could be to add a bunch of bh-disable
annotations to the spinlocks concerned - and there might be more than just
those two - but that means spending more time with BHs disabled.

Note also that some of these places were covered by bh-disable spinlocks
belonging to the rxrpc_transport object, but these got removed without the
_bh annotation being retained on the next lock in.

Fixes: 999b69f892 ("rxrpc: Kill the client connection bundle concept")
Reported-by: syzbot+d82f3ac8d87e7ccbb2c9@syzkaller.appspotmail.com
Reported-by: syzbot+3f1fd6b8cbf8702d134e@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hillf Danton <hdanton@sina.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-02-07 11:20:57 +01:00
David Howells 5273a191dc rxrpc: Fix NULL pointer deref due to call->conn being cleared on disconnect
When a call is disconnected, the connection pointer from the call is
cleared to make sure it isn't used again and to prevent further attempted
transmission for the call.  Unfortunately, there might be a daemon trying
to use it at the same time to transmit a packet.

Fix this by keeping call->conn set, but setting a flag on the call to
indicate disconnection instead.

Remove also the bits in the transmission functions where the conn pointer is
checked and a ref taken under spinlock as this is now redundant.

Fixes: 8d94aa381d ("rxrpc: Calls shouldn't hold socket refs")
Signed-off-by: David Howells <dhowells@redhat.com>
2020-02-03 10:25:30 +00:00
David Howells 91fcfbe885 rxrpc: Fix call crypto state cleanup
Fix the cleanup of the crypto state on a call after the call has been
disconnected.  As the call has been disconnected, its connection ref has
been discarded and so we can't go through that to get to the security ops
table.

Fix this by caching the security ops pointer in the rxrpc_call struct and
using that when freeing the call security state.  Also use this in other
places we're dealing with call-specific security.

The symptoms look like:

    BUG: KASAN: use-after-free in rxrpc_release_call+0xb2d/0xb60
    net/rxrpc/call_object.c:481
    Read of size 8 at addr ffff888062ffeb50 by task syz-executor.5/4764

Fixes: 1db88c5343 ("rxrpc: Fix -Wframe-larger-than= warnings from on-stack crypto")
Reported-by: syzbot+eed305768ece6682bb7f@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
2019-10-07 11:05:05 +01:00
David Howells 48c9e0ec7c rxrpc: Fix trace-after-put looking at the put call record
rxrpc_put_call() calls trace_rxrpc_call() after it has done the decrement
of the refcount - which looks at the debug_id in the call record.  But
unless the refcount was reduced to zero, we no longer have the right to
look in the record and, indeed, it may be deleted by some other thread.

Fix this by getting the debug_id out before decrementing the refcount and
then passing that into the tracepoint.

Fixes: e34d4234b0 ("rxrpc: Trace rxrpc_call usage")
Signed-off-by: David Howells <dhowells@redhat.com>
2019-10-07 11:05:05 +01:00
David S. Miller 765b7590c9 Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
r8152 conflicts are the NAPI fixes in 'net' overlapping with
some tasklet stuff in net-next

Signed-off-by: David S. Miller <davem@davemloft.net>
2019-09-02 11:20:17 -07:00
David Howells 987db9f7cd rxrpc: Use the tx-phase skb flag to simplify tracing
Use the previously-added transmit-phase skbuff private flag to simplify the
socket buffer tracing a bit.  Which phase the skbuff comes from can now be
divined from the skb rather than having to be guessed from the call state.

We can also reduce the number of rxrpc_skb_trace values by eliminating the
difference between Tx and Rx in the symbols.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-08-27 10:04:18 +01:00
David Howells a641fd00d0 rxrpc: Abstract out rxtx ring cleanup
Abstract out rxtx ring cleanup into its own function from its two callers.
This makes it easier to apply the same changes to both.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-08-27 10:03:26 +01:00
David Howells 1db88c5343 rxrpc: Fix -Wframe-larger-than= warnings from on-stack crypto
rxkad sometimes triggers a warning about oversized stack frames when
building with clang for a 32-bit architecture:

net/rxrpc/rxkad.c:243:12: error: stack frame size of 1088 bytes in function 'rxkad_secure_packet' [-Werror,-Wframe-larger-than=]
net/rxrpc/rxkad.c:501:12: error: stack frame size of 1088 bytes in function 'rxkad_verify_packet' [-Werror,-Wframe-larger-than=]

The problem is the combination of SYNC_SKCIPHER_REQUEST_ON_STACK() in
rxkad_verify_packet()/rxkad_secure_packet() with the relatively large
scatterlist in rxkad_verify_packet_1()/rxkad_secure_packet_encrypt().

The warning does not show up when using gcc, which does not inline the
functions as aggressively, but the problem is still the same.

Allocate the cipher buffers from the slab instead, caching the allocated
packet crypto request memory used for DATA packet crypto in the rxrpc_call
struct.

Fixes: 17926a7932 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-07-30 10:32:35 -07:00
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00
David Howells b960a34b73 rxrpc: Allow the kernel to mark a call as being non-interruptible
Allow kernel services using AF_RXRPC to indicate that a call should be
non-interruptible.  This allows kafs to make things like lock-extension and
writeback data storage calls non-interruptible.

If this is set, signals will be ignored for operations on that call where
possible - such as waiting to get a call channel on an rxrpc connection.

It doesn't prevent UDP sendmsg from being interrupted, but that will be
handled by packet retransmission.

rxrpc_kernel_recv_data() isn't affected by this since that never waits,
preferring instead to return -EAGAIN and leave the waiting to the caller.

Userspace initiated calls can't be set to be uninterruptible at this time.

Signed-off-by: David Howells <dhowells@redhat.com>
2019-05-16 16:25:20 +01:00
David Howells b13023421b rxrpc: Fix net namespace cleanup
In rxrpc_destroy_all_calls(), there are two phases: (1) make sure the
->calls list is empty, emitting error messages if not, and (2) wait for the
RCU cleanup to happen on outstanding calls (ie. ->nr_calls becomes 0).

To avoid taking the call_lock, the function prechecks ->calls and if empty,
it returns to avoid taking the lock - this is wrong, however: it still
needs to go and do the second phase and wait for ->nr_calls to become 0.

Without this, the rxrpc_net struct may get deallocated before we get to the
RCU cleanup for the last calls.  This can lead to:

  Slab corruption (Not tainted): kmalloc-16k start=ffff88802b178000, len=16384
  050: 6b 6b 6b 6b 6b 6b 6b 6b 61 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkakkkkkkk

Note the "61" at offset 0x58.  This corresponds to the ->nr_calls member of
struct rxrpc_net (which is >9k in size, and thus allocated out of the 16k
slab).

Fix this by flipping the condition on the if-statement, putting the locked
section inside the if-body and dropping the return from there.  The
function will then always go on to wait for the RCU cleanup on outstanding
calls.

Fixes: 2baec2c3f8 ("rxrpc: Support network namespacing")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-04-30 10:50:50 -04:00
David Howells e122d845a0 Revert "rxrpc: Allow failed client calls to be retried"
The changes introduced to allow rxrpc calls to be retried creates an issue
when it comes to refcounting afs_call structs.  The problem is that when
rxrpc_send_data() queues the last packet for an asynchronous call, the
following sequence can occur:

 (1) The notify_end_tx callback is invoked which causes the state in the
     afs_call to be changed from AFS_CALL_CL_REQUESTING or
     AFS_CALL_SV_REPLYING.

 (2) afs_deliver_to_call() can then process event notifications from rxrpc
     on the async_work queue.

 (3) Delivery of events, such as an abort from the server, can cause the
     afs_call state to be changed to AFS_CALL_COMPLETE on async_work.

 (4) For an asynchronous call, afs_process_async_call() notes that the call
     is complete and tried to clean up all the refs on async_work.

 (5) rxrpc_send_data() might return the amount of data transferred
     (success) or an error - which could in turn reflect a local error or a
     received error.

Synchronising the clean up after rxrpc_kernel_send_data() returns an error
with the asynchronous cleanup is then tricky to get right.

Mostly revert commit c038a58ccf.  The two API
functions the original commit added aren't currently used.  This makes
rxrpc_kernel_send_data() always return successfully if it queued the data
it was given.

Note that this doesn't affect synchronous calls since their Rx notification
function merely pokes a wait queue and does not refcounting.  The
asynchronous call notification function *has* to do refcounting and pass a
ref over the work item to avoid the need to sync the workqueue in call
cleanup.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-15 21:33:36 -08:00
David Howells c1e15b4944 rxrpc: Fix the packet reception routine
The rxrpc_input_packet() function and its call tree was built around the
assumption that data_ready() handler called from UDP to inform a kernel
service that there is data to be had was non-reentrant.  This means that
certain locking could be dispensed with.

This, however, turns out not to be the case with a multi-queue network card
that can deliver packets to multiple cpus simultaneously.  Each of those
cpus can be in the rxrpc_input_packet() function at the same time.

Fix by adding or changing some structure members:

 (1) Add peer->rtt_input_lock to serialise access to the RTT buffer.

 (2) Make conn->service_id into a 32-bit variable so that it can be
     cmpxchg'd on all arches.

 (3) Add call->input_lock to serialise access to the Rx/Tx state.  Note
     that although the Rx and Tx states are (almost) entirely separate,
     there's no point completing the separation and having separate locks
     since it's a bi-phasal RPC protocol rather than a bi-direction
     streaming protocol.  Data transmission and data reception do not take
     place simultaneously on any particular call.

and making the following functional changes:

 (1) In rxrpc_input_data(), hold call->input_lock around the core to
     prevent simultaneous producing of packets into the Rx ring and
     updating of tracking state for a particular call.

 (2) In rxrpc_input_ping_response(), only read call->ping_serial once, and
     check it before checking RXRPC_CALL_PINGING as that's a cheaper test.
     The bit test and bit clear can then be combined.  No further locking
     is needed here.

 (3) In rxrpc_input_ack(), take call->input_lock after we've parsed much of
     the ACK packet.  The superseded ACK check is then done both before and
     after the lock is taken.

     The handing of ackinfo data is split, parsing before the lock is taken
     and processing with it held.  This is keyed on rxMTU being non-zero.

     Congestion management is also done within the locked section.

 (4) In rxrpc_input_ackall(), take call->input_lock around the Tx window
     rotation.  The ACKALL packet carries no information and is only really
     useful after all packets have been transmitted since it's imprecise.

 (5) In rxrpc_input_implicit_end_call(), we use rx->incoming_lock to
     prevent calls being simultaneously implicitly ended on two cpus and
     also to prevent any races with incoming call setup.

 (6) In rxrpc_input_packet(), use cmpxchg() to effect the service upgrade
     on a connection.  It is only permitted to happen once for a
     connection.

 (7) In rxrpc_new_incoming_call(), we have to recheck the routing inside
     rx->incoming_lock to see if someone else set up the call, connection
     or peer whilst we were getting there.  We can't trust the values from
     the earlier routing check unless we pin refs on them - which we want
     to avoid.

     Further, we need to allow for an incoming call to have its state
     changed on another CPU between us making it live and us adjusting it
     because the conn is now in the RXRPC_CONN_SERVICE state.

 (8) In rxrpc_peer_add_rtt(), take peer->rtt_input_lock around the access
     to the RTT buffer.  Don't need to lock around setting peer->rtt.

For reference, the inventory of state-accessing or state-altering functions
used by the packet input procedure is:

> rxrpc_input_packet()
  * PACKET CHECKING

  * ROUTING
    > rxrpc_post_packet_to_local()
    > rxrpc_find_connection_rcu() - uses RCU
      > rxrpc_lookup_peer_rcu() - uses RCU
      > rxrpc_find_service_conn_rcu() - uses RCU
      > idr_find() - uses RCU

  * CONNECTION-LEVEL PROCESSING
    - Service upgrade
      - Can only happen once per conn
      ! Changed to use cmpxchg
    > rxrpc_post_packet_to_conn()
    - Setting conn->hi_serial
      - Probably safe not using locks
      - Maybe use cmpxchg

  * CALL-LEVEL PROCESSING
    > Old-call checking
      > rxrpc_input_implicit_end_call()
        > rxrpc_call_completed()
	> rxrpc_queue_call()
	! Need to take rx->incoming_lock
	> __rxrpc_disconnect_call()
	> rxrpc_notify_socket()
    > rxrpc_new_incoming_call()
      - Uses rx->incoming_lock for the entire process
        - Might be able to drop this earlier in favour of the call lock
      > rxrpc_incoming_call()
      	! Conflicts with rxrpc_input_implicit_end_call()
    > rxrpc_send_ping()
      - Don't need locks to check rtt state
      > rxrpc_propose_ACK

  * PACKET DISTRIBUTION
    > rxrpc_input_call_packet()
      > rxrpc_input_data()
	* QUEUE DATA PACKET ON CALL
	> rxrpc_reduce_call_timer()
	  - Uses timer_reduce()
	! Needs call->input_lock()
	> rxrpc_receiving_reply()
	  ! Needs locking around ack state
	  > rxrpc_rotate_tx_window()
	  > rxrpc_end_tx_phase()
	> rxrpc_proto_abort()
	> rxrpc_input_dup_data()
	- Fills the Rx buffer
	- rxrpc_propose_ACK()
	- rxrpc_notify_socket()

      > rxrpc_input_ack()
	* APPLY ACK PACKET TO CALL AND DISCARD PACKET
	> rxrpc_input_ping_response()
	  - Probably doesn't need any extra locking
	  ! Need READ_ONCE() on call->ping_serial
	  > rxrpc_input_check_for_lost_ack()
	    - Takes call->lock to consult Tx buffer
	  > rxrpc_peer_add_rtt()
	    ! Needs to take a lock (peer->rtt_input_lock)
	    ! Could perhaps manage with cmpxchg() and xadd() instead
	> rxrpc_input_requested_ack
	  - Consults Tx buffer
	    ! Probably needs a lock
	  > rxrpc_peer_add_rtt()
	> rxrpc_propose_ack()
	> rxrpc_input_ackinfo()
	  - Changes call->tx_winsize
	    ! Use cmpxchg to handle change
	    ! Should perhaps track serial number
	  - Uses peer->lock to record MTU specification changes
	> rxrpc_proto_abort()
	! Need to take call->input_lock
	> rxrpc_rotate_tx_window()
	> rxrpc_end_tx_phase()
	> rxrpc_input_soft_acks()
	- Consults the Tx buffer
	> rxrpc_congestion_management()
	  - Modifies the Tx annotations
	  ! Needs call->input_lock()
	  > rxrpc_queue_call()

      > rxrpc_input_abort()
	* APPLY ABORT PACKET TO CALL AND DISCARD PACKET
	> rxrpc_set_call_completion()
	> rxrpc_notify_socket()

      > rxrpc_input_ackall()
	* APPLY ACKALL PACKET TO CALL AND DISCARD PACKET
	! Need to take call->input_lock
	> rxrpc_rotate_tx_window()
	> rxrpc_end_tx_phase()

    > rxrpc_reject_packet()

There are some functions used by the above that queue the packet, after
which the procedure is terminated:

 - rxrpc_post_packet_to_local()
   - local->event_queue is an sk_buff_head
   - local->processor is a work_struct
 - rxrpc_post_packet_to_conn()
   - conn->rx_queue is an sk_buff_head
   - conn->processor is a work_struct
 - rxrpc_reject_packet()
   - local->reject_queue is an sk_buff_head
   - local->processor is a work_struct

And some that offload processing to process context:

 - rxrpc_notify_socket()
   - Uses RCU lock
   - Uses call->notify_lock to call call->notify_rx
   - Uses call->recvmsg_lock to queue recvmsg side
 - rxrpc_queue_call()
   - call->processor is a work_struct
 - rxrpc_propose_ACK()
   - Uses call->lock to wrap __rxrpc_propose_ACK()

And a bunch that complete a call, all of which use call->state_lock to
protect the call state:

 - rxrpc_call_completed()
 - rxrpc_set_call_completion()
 - rxrpc_abort_call()
 - rxrpc_proto_abort()
   - Also uses rxrpc_queue_call()

Fixes: 17926a7932 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: David Howells <dhowells@redhat.com>
2018-10-08 22:42:04 +01:00
David Howells 5e33a23ba4 rxrpc: Fix some missed refs to init_net
Fix some refs to init_net that should've been changed to the appropriate
network namespace.

Fixes: 2baec2c3f8 ("rxrpc: Support network namespacing")
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Paolo Abeni <pabeni@redhat.com>
2018-10-05 14:21:59 +01:00
David Howells f334430316 rxrpc: Fix error distribution
Fix error distribution by immediately delivering the errors to all the
affected calls rather than deferring them to a worker thread.  The problem
with the latter is that retries and things can happen in the meantime when we
want to stop that sooner.

To this end:

 (1) Stop the error distributor from removing calls from the error_targets
     list so that peer->lock isn't needed to synchronise against other adds
     and removals.

 (2) Require the peer's error_targets list to be accessed with RCU, thereby
     avoiding the need to take peer->lock over distribution.

 (3) Don't attempt to affect a call's state if it is already marked complete.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-09-28 10:33:17 +01:00
Mark Rutland bfc18e389c atomics/treewide: Rename __atomic_add_unless() => atomic_fetch_add_unless()
While __atomic_add_unless() was originally intended as a building-block
for atomic_add_unless(), it's now used in a number of places around the
kernel. It's the only common atomic operation named __atomic*(), rather
than atomic_*(), and for consistency it would be better named
atomic_fetch_add_unless().

This lack of consistency is slightly confusing, and gets in the way of
scripting atomics. Given that, let's clean things up and promote it to
an official part of the atomics API, in the form of
atomic_fetch_add_unless().

This patch converts definitions and invocations over to the new name,
including the instrumented version, using the following script:

  ----
  git grep -w __atomic_add_unless | while read line; do
  sed -i '{s/\<__atomic_add_unless\>/atomic_fetch_add_unless/}' "${line%%:*}";
  done
  git grep -w __arch_atomic_add_unless | while read line; do
  sed -i '{s/\<__arch_atomic_add_unless\>/arch_atomic_fetch_add_unless/}' "${line%%:*}";
  done
  ----

Note that we do not have atomic{64,_long}_fetch_add_unless(), which will
be introduced by later patches.

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Will Deacon <will.deacon@arm.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Palmer Dabbelt <palmer@sifive.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/lkml/20180621121321.4761-2-mark.rutland@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-06-21 14:22:32 +02:00
Linus Torvalds 5bb053bef8 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller:

 1) Support offloading wireless authentication to userspace via
    NL80211_CMD_EXTERNAL_AUTH, from Srinivas Dasari.

 2) A lot of work on network namespace setup/teardown from Kirill Tkhai.
    Setup and cleanup of namespaces now all run asynchronously and thus
    performance is significantly increased.

 3) Add rx/tx timestamping support to mv88e6xxx driver, from Brandon
    Streiff.

 4) Support zerocopy on RDS sockets, from Sowmini Varadhan.

 5) Use denser instruction encoding in x86 eBPF JIT, from Daniel
    Borkmann.

 6) Support hw offload of vlan filtering in mvpp2 dreiver, from Maxime
    Chevallier.

 7) Support grafting of child qdiscs in mlxsw driver, from Nogah
    Frankel.

 8) Add packet forwarding tests to selftests, from Ido Schimmel.

 9) Deal with sub-optimal GSO packets better in BBR congestion control,
    from Eric Dumazet.

10) Support 5-tuple hashing in ipv6 multipath routing, from David Ahern.

11) Add path MTU tests to selftests, from Stefano Brivio.

12) Various bits of IPSEC offloading support for mlx5, from Aviad
    Yehezkel, Yossi Kuperman, and Saeed Mahameed.

13) Support RSS spreading on ntuple filters in SFC driver, from Edward
    Cree.

14) Lots of sockmap work from John Fastabend. Applications can use eBPF
    to filter sendmsg and sendpage operations.

15) In-kernel receive TLS support, from Dave Watson.

16) Add XDP support to ixgbevf, this is significant because it should
    allow optimized XDP usage in various cloud environments. From Tony
    Nguyen.

17) Add new Intel E800 series "ice" ethernet driver, from Anirudh
    Venkataramanan et al.

18) IP fragmentation match offload support in nfp driver, from Pieter
    Jansen van Vuuren.

19) Support XDP redirect in i40e driver, from Björn Töpel.

20) Add BPF_RAW_TRACEPOINT program type for accessing the arguments of
    tracepoints in their raw form, from Alexei Starovoitov.

21) Lots of striding RQ improvements to mlx5 driver with many
    performance improvements, from Tariq Toukan.

22) Use rhashtable for inet frag reassembly, from Eric Dumazet.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1678 commits)
  net: mvneta: improve suspend/resume
  net: mvneta: split rxq/txq init and txq deinit into SW and HW parts
  ipv6: frags: fix /proc/sys/net/ipv6/ip6frag_low_thresh
  net: bgmac: Fix endian access in bgmac_dma_tx_ring_free()
  net: bgmac: Correctly annotate register space
  route: check sysctl_fib_multipath_use_neigh earlier than hash
  fix typo in command value in drivers/net/phy/mdio-bitbang.
  sky2: Increase D3 delay to sky2 stops working after suspend
  net/mlx5e: Set EQE based as default TX interrupt moderation mode
  ibmvnic: Disable irqs before exiting reset from closed state
  net: sched: do not emit messages while holding spinlock
  vlan: also check phy_driver ts_info for vlan's real device
  Bluetooth: Mark expected switch fall-throughs
  Bluetooth: Set HCI_QUIRK_SIMULTANEOUS_DISCOVERY for BTUSB_QCA_ROME
  Bluetooth: btrsi: remove unused including <linux/version.h>
  Bluetooth: hci_bcm: Remove DMI quirk for the MINIX Z83-4
  sh_eth: kill useless check in __sh_eth_get_regs()
  sh_eth: add sh_eth_cpu_data::no_xdfar flag
  ipv6: factorize sk_wmem_alloc updates done by __ip6_append_data()
  ipv4: factorize sk_wmem_alloc updates done by __ip_append_data()
  ...
2018-04-03 14:04:18 -07:00
David Howells d3be4d2443 rxrpc: Fix potential call vs socket/net destruction race
rxrpc_call structs don't pin sockets or network namespaces, but may attempt
to access both after their refcount reaches 0 so that they can detach
themselves from the network namespace.  However, there's no guarantee that
the socket still exists at this point (so sock_net(&call->socket->sk) may
be invalid) and the namespace may have gone away if the call isn't pinning
a peer.

Fix this by (a) carrying a net pointer in the rxrpc_call struct and (b)
waiting for all calls to be destroyed when the network namespace goes away.

This was detected by checker:

net/rxrpc/call_object.c:634:57: warning: incorrect type in argument 1 (different address spaces)
net/rxrpc/call_object.c:634:57:    expected struct sock const *sk
net/rxrpc/call_object.c:634:57:    got struct sock [noderef] <asn:4>*<noident>

Fixes: 2baec2c3f8 ("rxrpc: Support network namespacing")
Signed-off-by: David Howells <dhowells@redhat.com>
2018-03-30 21:05:23 +01:00
David Howells 88f2a8257c rxrpc: Fix checker warnings and errors
Fix various issues detected by checker.

Errors:

 (*) rxrpc_discard_prealloc() should be using rcu_assign_pointer to set
     call->socket.

Warnings:

 (*) rxrpc_service_connection_reaper() should be passing NULL rather than 0 to
     trace_rxrpc_conn() as the where argument.

 (*) rxrpc_disconnect_client_call() should get its net pointer via the
     call->conn rather than call->sock to avoid a warning about accessing
     an RCU pointer without protection.

 (*) Proc seq start/stop functions need annotation as they pass locks
     between the functions.

False positives:

 (*) Checker doesn't correctly handle of seq-retry lock context balance in
     rxrpc_find_service_conn_rcu().

 (*) Checker thinks execution may proceed past the BUG() in
     rxrpc_publish_service_conn().

 (*) Variable length array warnings from SKCIPHER_REQUEST_ON_STACK() in
     rxkad.c.

Signed-off-by: David Howells <dhowells@redhat.com>
2018-03-30 21:05:17 +01:00