stable inclusion
from stable-v5.10.157
commit 23c03ee0eec4424a54a5619b23954d9069bac026
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7MU59

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=23c03ee0eec4424a54a5619b23954d9069bac026

--------------------------------

[ Upstream commit a0575429 ]

Move to using refcount_t rather than atomic_t for refcounts in rxrpc.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Marc Dionne <marc.dionne@auristor.com>
cc: linux-afs@lists.infradead.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Stable-dep-of: 3bcd6c7e ("rxrpc: Fix race between conn bundle lookup and bundle removal [ZDI-CAN-15975]")
Signed-off-by: NSasha Levin <sashal@kernel.org>
Signed-off-by: Nsanglipeng <sanglipeng1@jd.com>

Conflicts:
	net/rxrpc/ar-internal.h
	net/rxrpc/conn_client.c

stable inclusion
from stable-5.10.13
commit 2e83a57a23a6c08308baebec660d1fdd82b3a4ea
bugzilla: 47995

--------------------------------

commit b8323f72 upstream.

Commit 9ebeddef ("rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record")
Then release ref in __rxrpc_put_peer and rxrpc_put_peer_locked.

	struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
	-               peer->local = local;
	+               peer->local = rxrpc_get_local(local);

rxrpc_discard_prealloc also need ref release in discarding.

syzbot report:
BUG: memory leak
unreferenced object 0xffff8881080ddc00 (size 256):
  comm "syz-executor339", pid 8462, jiffies 4294942238 (age 12.350s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 0a 00 00 00 00 c0 00 08 81 88 ff ff  ................
  backtrace:
    [<000000002b6e495f>] kmalloc include/linux/slab.h:552 [inline]
    [<000000002b6e495f>] kzalloc include/linux/slab.h:682 [inline]
    [<000000002b6e495f>] rxrpc_alloc_local net/rxrpc/local_object.c:79 [inline]
    [<000000002b6e495f>] rxrpc_lookup_local+0x1c1/0x760 net/rxrpc/local_object.c:244
    [<000000006b43a77b>] rxrpc_bind+0x174/0x240 net/rxrpc/af_rxrpc.c:149
    [<00000000fd447a55>] afs_open_socket+0xdb/0x200 fs/afs/rxrpc.c:64
    [<000000007fd8867c>] afs_net_init+0x2b4/0x340 fs/afs/main.c:126
    [<0000000063d80ec1>] ops_init+0x4e/0x190 net/core/net_namespace.c:152
    [<00000000073c5efa>] setup_net+0xde/0x2d0 net/core/net_namespace.c:342
    [<00000000a6744d5b>] copy_net_ns+0x19f/0x3e0 net/core/net_namespace.c:483
    [<0000000017d3aec3>] create_new_namespaces+0x199/0x4f0 kernel/nsproxy.c:110
    [<00000000186271ef>] unshare_nsproxy_namespaces+0x9b/0x120 kernel/nsproxy.c:226
    [<000000002de7bac4>] ksys_unshare+0x2fe/0x5c0 kernel/fork.c:2957
    [<00000000349b12ba>] __do_sys_unshare kernel/fork.c:3025 [inline]
    [<00000000349b12ba>] __se_sys_unshare kernel/fork.c:3023 [inline]
    [<00000000349b12ba>] __x64_sys_unshare+0x12/0x20 kernel/fork.c:3023
    [<000000006d178ef7>] do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
    [<00000000637076d4>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 9ebeddef ("rxrpc: rxrpc_peer needs to hold a ref on the rxrpc_local record")
Signed-off-by: NTakeshi Misawa <jeliantsurux@gmail.com>
Reported-and-tested-by: syzbot+305326672fed51b205f7@syzkaller.appspotmail.com
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Link: https://lore.kernel.org/r/161183091692.3506637.3206605651502458810.stgit@warthog.procyon.org.ukSigned-off-by: NJakub Kicinski <kuba@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

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: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-throughSigned-off-by: NGustavo A. R. Silva <gustavoars@kernel.org>

When preallocated service calls are being discarded, they're passed to
->discard_new_call() to have the caller clean up any attached higher-layer
preallocated pieces before being marked completed.  However, the act of
marking them completed now invokes the call's notification function - which
causes a problem because that function might assume that the previously
freed pieces of memory are still there.

Fix this by setting a dummy notification function on the socket after
calling ->discard_new_call().

This results in the following kasan message when the kafs module is
removed.

==================================================================
BUG: KASAN: use-after-free in afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707
Write of size 1 at addr ffff8880946c39e4 by task kworker/u4:1/21

CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.8.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 afs_wake_up_async_call+0x6aa/0x770 fs/afs/rxrpc.c:707
 rxrpc_notify_socket+0x1db/0x5d0 net/rxrpc/recvmsg.c:40
 __rxrpc_set_call_completion.part.0+0x172/0x410 net/rxrpc/recvmsg.c:76
 __rxrpc_call_completed net/rxrpc/recvmsg.c:112 [inline]
 rxrpc_call_completed+0xca/0xf0 net/rxrpc/recvmsg.c:111
 rxrpc_discard_prealloc+0x781/0xab0 net/rxrpc/call_accept.c:233
 rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245
 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186
 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603
 process_one_work+0x965/0x1690 kernel/workqueue.c:2269
 worker_thread+0x96/0xe10 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

Allocated by task 6820:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc mm/kasan/common.c:494 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467
 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 afs_alloc_call+0x55/0x630 fs/afs/rxrpc.c:141
 afs_charge_preallocation+0xe9/0x2d0 fs/afs/rxrpc.c:757
 afs_open_socket+0x292/0x360 fs/afs/rxrpc.c:92
 afs_net_init+0xa6c/0xe30 fs/afs/main.c:125
 ops_init+0xaf/0x420 net/core/net_namespace.c:151
 setup_net+0x2de/0x860 net/core/net_namespace.c:341
 copy_net_ns+0x293/0x590 net/core/net_namespace.c:482
 create_new_namespaces+0x3fb/0xb30 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:231
 ksys_unshare+0x43d/0x8e0 kernel/fork.c:2983
 __do_sys_unshare kernel/fork.c:3051 [inline]
 __se_sys_unshare kernel/fork.c:3049 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3049
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 21:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 afs_put_call+0x585/0xa40 fs/afs/rxrpc.c:190
 rxrpc_discard_prealloc+0x764/0xab0 net/rxrpc/call_accept.c:230
 rxrpc_listen+0x147/0x360 net/rxrpc/af_rxrpc.c:245
 afs_close_socket+0x95/0x320 fs/afs/rxrpc.c:110
 afs_net_exit+0x1bc/0x310 fs/afs/main.c:155
 ops_exit_list.isra.0+0xa8/0x150 net/core/net_namespace.c:186
 cleanup_net+0x511/0xa50 net/core/net_namespace.c:603
 process_one_work+0x965/0x1690 kernel/workqueue.c:2269
 worker_thread+0x96/0xe10 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

The buggy address belongs to the object at ffff8880946c3800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 484 bytes inside of
 1024-byte region [ffff8880946c3800, ffff8880946c3c00)
The buggy address belongs to the page:
page:ffffea000251b0c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea0002546508 ffffea00024fa248 ffff8880aa000c40
raw: 0000000000000000 ffff8880946c3000 0000000100000002 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880946c3880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880946c3900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880946c3980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff8880946c3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880946c3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Reported-by: syzbot+d3eccef36ddbd02713e9@syzkaller.appspotmail.com
Fixes: 5ac0d622 ("rxrpc: Fix missing notification")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rxrpc currently uses a fixed 4s retransmission timeout until the RTT is
sufficiently sampled.  This can cause problems with some fileservers with
calls to the cache manager in the afs filesystem being dropped from the
fileserver because a packet goes missing and the retransmission timeout is
greater than the call expiry timeout.

Fix this by:

 (1) Copying the RTT/RTO calculation code from Linux's TCP implementation
     and altering it to fit rxrpc.

 (2) Altering the various users of the RTT to make use of the new SRTT
     value.

 (3) Replacing the use of rxrpc_resend_timeout to use the calculated RTO
     value instead (which is needed in jiffies), along with a backoff.

Notes:

 (1) rxrpc provides RTT samples by matching the serial numbers on outgoing
     DATA packets that have the RXRPC_REQUEST_ACK set and PING ACK packets
     against the reference serial number in incoming REQUESTED ACK and
     PING-RESPONSE ACK packets.

 (2) Each packet that is transmitted on an rxrpc connection gets a new
     per-connection serial number, even for retransmissions, so an ACK can
     be cross-referenced to a specific trigger packet.  This allows RTT
     information to be drawn from retransmitted DATA packets also.

 (3) rxrpc maintains the RTT/RTO state on the rxrpc_peer record rather than
     on an rxrpc_call because many RPC calls won't live long enough to
     generate more than one sample.

 (4) The calculated SRTT value is in units of 8ths of a microsecond rather
     than nanoseconds.

The (S)RTT and RTO values are displayed in /proc/net/rxrpc/peers.

Fixes: 17926a79 ([AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both"")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix rxrpc_new_incoming_call() to check that we have a suitable service key
available for the combination of service ID and security class of a new
incoming call - and to reject calls for which we don't.

This causes an assertion like the following to appear:

	rxrpc: Assertion failed - 6(0x6) == 12(0xc) is false
	kernel BUG at net/rxrpc/call_object.c:456!

Where call->state is RXRPC_CALL_SERVER_SECURING (6) rather than
RXRPC_CALL_COMPLETE (12).

Fixes: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Reported-by: NMarc Dionne <marc.dionne@auristor.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Standard kernel mutexes cannot be used in any way from interrupt or softirq
context, so the user_mutex which manages access to a call cannot be a mutex
since on a new call the mutex must start off locked and be unlocked within
the softirq handler to prevent userspace interfering with a call we're
setting up.

Commit a0855d24 ("locking/mutex: Complain
upon mutex API misuse in IRQ contexts") causes big warnings to be splashed
in dmesg for each a new call that comes in from the server.  Whilst it
*seems* like it should be okay, since the accept path uses trylock, there
are issues with PI boosting and marking the wrong task as the owner.

Fix this by not taking the mutex in the softirq path at all.  It's not
obvious that there should be any need for it as the state is set before the
first notification is generated for the new call.

There's also no particular reason why the link-assessing ping should be
triggered inside the mutex.  It's not actually transmitted there anyway,
but rather it has to be deferred to a workqueue.

Further, I don't think that there's any particular reason that the socket
notification needs to be done from within rx->incoming_lock, so the amount
of time that lock is held can be shortened too and the ping prepared before
the new call notification is sent.

Fixes: 540b1c48 ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
cc: Peter Zijlstra (Intel) <peterz@infradead.org>
cc: Ingo Molnar <mingo@redhat.com>
cc: Will Deacon <will@kernel.org>
cc: Davidlohr Bueso <dave@stgolabs.net>

Move the unlock and the ping transmission for a new incoming call into
rxrpc_new_incoming_call() rather than doing it in the caller.  This makes
it clearer to see what's going on.
Suggested-by: NPeter Zijlstra <peterz@infradead.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
cc: Ingo Molnar <mingo@redhat.com>
cc: Will Deacon <will@kernel.org>
cc: Davidlohr Bueso <dave@stgolabs.net>

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: 1db88c53 ("rxrpc: Fix -Wframe-larger-than= warnings from on-stack crypto")
Reported-by: syzbot+eed305768ece6682bb7f@syzkaller.appspotmail.com
Signed-off-by: NDavid Howells <dhowells@redhat.com>

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: e34d4234 ("rxrpc: Trace rxrpc_call usage")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

rxrpc_put_*conn() calls trace_rxrpc_conn() after they have done the
decrement of the refcount - which looks at the debug_id in the connection
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: 363deeab ("rxrpc: Add connection tracepoint and client conn state tracepoint")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

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: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NAllison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.deSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix an uninitialised variable introduced by the last patch.  This can cause
a crash when a new call comes in to a local service, such as when an AFS
fileserver calls back to the local cache manager.

Fixes: c1e15b49 ("rxrpc: Fix the packet reception routine")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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: 17926a79 ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix connection-level abort handling to cache the abort and error codes
properly so that a new incoming call can be properly aborted if it races
with the parent connection being aborted by another CPU.

The abort_code and error parameters can then be dropped from
rxrpc_abort_calls().

Fixes: f5c17aae ("rxrpc: Calls should only have one terminal state")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix some refs to init_net that should've been changed to the appropriate
network namespace.

Fixes: 2baec2c3 ("rxrpc: Support network namespacing")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NPaolo Abeni <pabeni@redhat.com>

rxrpc_extract_addr_from_skb() doesn't use the argument that points to the
local endpoint, so remove the argument.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Make the following changes to improve the robustness of the code that sets
up a new service call:

 (1) Cache the rxrpc_sock struct obtained in rxrpc_data_ready() to do a
     service ID check and pass that along to rxrpc_new_incoming_call().
     This means that I can remove the check from rxrpc_new_incoming_call()
     without the need to worry about the socket attached to the local
     endpoint getting replaced - which would invalidate the check.

 (2) Cache the rxrpc_peer struct, thereby allowing the peer search to be
     done once.  The peer is passed to rxrpc_new_incoming_call(), thereby
     saving the need to repeat the search.

     This also reduces the possibility of rxrpc_publish_service_conn()
     BUG()'ing due to the detection of a duplicate connection, despite the
     initial search done by rxrpc_find_connection_rcu() having turned up
     nothing.

     This BUG() shouldn't ever get hit since rxrpc_data_ready() *should* be
     non-reentrant and the result of the initial search should still hold
     true, but it has proven possible to hit.

     I *think* this may be due to __rxrpc_lookup_peer_rcu() cutting short
     the iteration over the hash table if it finds a matching peer with a
     zero usage count, but I don't know for sure since it's only ever been
     hit once that I know of.

     Another possibility is that a bug in rxrpc_data_ready() that checked
     the wrong byte in the header for the RXRPC_CLIENT_INITIATED flag
     might've let through a packet that caused a spurious and invalid call
     to be set up.  That is addressed in another patch.

 (3) Fix __rxrpc_lookup_peer_rcu() to skip peer records that have a zero
     usage count rather than stopping and returning not found, just in case
     there's another peer record behind it in the bucket.

 (4) Don't search the peer records in rxrpc_alloc_incoming_call(), but
     rather either use the peer cached in (2) or, if one wasn't found,
     preemptively install a new one.

Fixes: 8496af50 ("rxrpc: Use RCU to access a peer's service connection tree")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

In the input path, a received sk_buff can be marked for rejection by
setting RXRPC_SKB_MARK_* in skb->mark and, if needed, some auxiliary data
(such as an abort code) in skb->priority.  The rejection is handled by
queueing the sk_buff up for dealing with in process context.  The output
code reads the mark and priority and, theoretically, generates an
appropriate response packet.

However, if RXRPC_SKB_MARK_BUSY is set, this isn't noticed and an ABORT
message with a random abort code is generated (since skb->priority wasn't
set to anything).

Fix this by outputting the appropriate sort of packet.

Also, whilst we're at it, most of the marks are no longer used, so remove
them and rename the remaining two to something more obvious.

Fixes: 248f219c ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

There just check the user call ID isn't already in use, hence should
compare user_call_ID with xcall->user_call_ID, which is current
node's user_call_ID.

Fixes: 540b1c48 ("rxrpc: Fix deadlock between call creation and sendmsg/recvmsg")
Suggested-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

rxrpc_local objects cannot be disposed of until all the connections that
point to them have been RCU'd as a connection object holds refcount on the
local endpoint it is communicating through.  Currently, this can cause an
assertion failure to occur when a network namespace is destroyed as there's
no check that the RCU destructors for the connections have been run before
we start trying to destroy local endpoints.

The kernel reports:

	rxrpc: AF_RXRPC: Leaked local 0000000036a41bc1 {5}
	------------[ cut here ]------------
	kernel BUG at ../net/rxrpc/local_object.c:439!

Fix this by keeping a count of the live connections and waiting for it to
go to zero at the end of rxrpc_destroy_all_connections().

Fixes: dee46364 ("rxrpc: Add RCU destruction for connections and calls")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to track reference counting on the rxrpc_local struct.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

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: 2baec2c3 ("rxrpc: Support network namespacing")
Signed-off-by: NDavid Howells <dhowells@redhat.com>

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: NDavid Howells <dhowells@redhat.com>

In rxrpc and afs, use the debug_ids that are monotonically allocated to
various objects as they're allocated rather than pointers as kernel
pointers are now hashed making them less useful.  Further, the debug ids
aren't reused anywhere nearly as quickly.

In addition, allow kernel services that use rxrpc, such as afs, to take
numbers from the rxrpc counter, assign them to their own call struct and
pass them in to rxrpc for both client and service calls so that the trace
lines for each will have the same ID tag.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Provide a different lockdep key for rxrpc_call::user_mutex when the call is
made on a kernel socket, such as by the AFS filesystem.

The problem is that lockdep registers a false positive between userspace
calling the sendmsg syscall on a user socket where call->user_mutex is held
whilst userspace memory is accessed whereas the AFS filesystem may perform
operations with mmap_sem held by the caller.

In such a case, the following warning is produced.

======================================================
WARNING: possible circular locking dependency detected
4.14.0-fscache+ #243 Tainted: G            E
------------------------------------------------------
modpost/16701 is trying to acquire lock:
 (&vnode->io_lock){+.+.}, at: [<ffffffffa000fc40>] afs_begin_vnode_operation+0x33/0x77 [kafs]

but task is already holding lock:
 (&mm->mmap_sem){++++}, at: [<ffffffff8104376a>] __do_page_fault+0x1ef/0x486

which lock already depends on the new lock.

the existing dependency chain (in reverse order) is:

-> #3 (&mm->mmap_sem){++++}:
       __might_fault+0x61/0x89
       _copy_from_iter_full+0x40/0x1fa
       rxrpc_send_data+0x8dc/0xff3
       rxrpc_do_sendmsg+0x62f/0x6a1
       rxrpc_sendmsg+0x166/0x1b7
       sock_sendmsg+0x2d/0x39
       ___sys_sendmsg+0x1ad/0x22b
       __sys_sendmsg+0x41/0x62
       do_syscall_64+0x89/0x1be
       return_from_SYSCALL_64+0x0/0x75

-> #2 (&call->user_mutex){+.+.}:
       __mutex_lock+0x86/0x7d2
       rxrpc_new_client_call+0x378/0x80e
       rxrpc_kernel_begin_call+0xf3/0x154
       afs_make_call+0x195/0x454 [kafs]
       afs_vl_get_capabilities+0x193/0x198 [kafs]
       afs_vl_lookup_vldb+0x5f/0x151 [kafs]
       afs_create_volume+0x2e/0x2f4 [kafs]
       afs_mount+0x56a/0x8d7 [kafs]
       mount_fs+0x6a/0x109
       vfs_kern_mount+0x67/0x135
       do_mount+0x90b/0xb57
       SyS_mount+0x72/0x98
       do_syscall_64+0x89/0x1be
       return_from_SYSCALL_64+0x0/0x75

-> #1 (k-sk_lock-AF_RXRPC){+.+.}:
       lock_sock_nested+0x74/0x8a
       rxrpc_kernel_begin_call+0x8a/0x154
       afs_make_call+0x195/0x454 [kafs]
       afs_fs_get_capabilities+0x17a/0x17f [kafs]
       afs_probe_fileserver+0xf7/0x2f0 [kafs]
       afs_select_fileserver+0x83f/0x903 [kafs]
       afs_fetch_status+0x89/0x11d [kafs]
       afs_iget+0x16f/0x4f8 [kafs]
       afs_mount+0x6c6/0x8d7 [kafs]
       mount_fs+0x6a/0x109
       vfs_kern_mount+0x67/0x135
       do_mount+0x90b/0xb57
       SyS_mount+0x72/0x98
       do_syscall_64+0x89/0x1be
       return_from_SYSCALL_64+0x0/0x75

-> #0 (&vnode->io_lock){+.+.}:
       lock_acquire+0x174/0x19f
       __mutex_lock+0x86/0x7d2
       afs_begin_vnode_operation+0x33/0x77 [kafs]
       afs_fetch_data+0x80/0x12a [kafs]
       afs_readpages+0x314/0x405 [kafs]
       __do_page_cache_readahead+0x203/0x2ba
       filemap_fault+0x179/0x54d
       __do_fault+0x17/0x60
       __handle_mm_fault+0x6d7/0x95c
       handle_mm_fault+0x24e/0x2a3
       __do_page_fault+0x301/0x486
       do_page_fault+0x236/0x259
       page_fault+0x22/0x30
       __clear_user+0x3d/0x60
       padzero+0x1c/0x2b
       load_elf_binary+0x785/0xdc7
       search_binary_handler+0x81/0x1ff
       do_execveat_common.isra.14+0x600/0x888
       do_execve+0x1f/0x21
       SyS_execve+0x28/0x2f
       do_syscall_64+0x89/0x1be
       return_from_SYSCALL_64+0x0/0x75

other info that might help us debug this:

Chain exists of:
  &vnode->io_lock --> &call->user_mutex --> &mm->mmap_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&mm->mmap_sem);
                               lock(&call->user_mutex);
                               lock(&mm->mmap_sem);
  lock(&vnode->io_lock);

 *** DEADLOCK ***

1 lock held by modpost/16701:
 #0:  (&mm->mmap_sem){++++}, at: [<ffffffff8104376a>] __do_page_fault+0x1ef/0x486

stack backtrace:
CPU: 0 PID: 16701 Comm: modpost Tainted: G            E   4.14.0-fscache+ #243
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Call Trace:
 dump_stack+0x67/0x8e
 print_circular_bug+0x341/0x34f
 check_prev_add+0x11f/0x5d4
 ? add_lock_to_list.isra.12+0x8b/0x8b
 ? add_lock_to_list.isra.12+0x8b/0x8b
 ? __lock_acquire+0xf77/0x10b4
 __lock_acquire+0xf77/0x10b4
 lock_acquire+0x174/0x19f
 ? afs_begin_vnode_operation+0x33/0x77 [kafs]
 __mutex_lock+0x86/0x7d2
 ? afs_begin_vnode_operation+0x33/0x77 [kafs]
 ? afs_begin_vnode_operation+0x33/0x77 [kafs]
 ? afs_begin_vnode_operation+0x33/0x77 [kafs]
 afs_begin_vnode_operation+0x33/0x77 [kafs]
 afs_fetch_data+0x80/0x12a [kafs]
 afs_readpages+0x314/0x405 [kafs]
 __do_page_cache_readahead+0x203/0x2ba
 ? filemap_fault+0x179/0x54d
 filemap_fault+0x179/0x54d
 __do_fault+0x17/0x60
 __handle_mm_fault+0x6d7/0x95c
 handle_mm_fault+0x24e/0x2a3
 __do_page_fault+0x301/0x486
 do_page_fault+0x236/0x259
 page_fault+0x22/0x30
RIP: 0010:__clear_user+0x3d/0x60
RSP: 0018:ffff880071e93da0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000011c RCX: 000000000000011c
RDX: 0000000000000000 RSI: 0000000000000008 RDI: 000000000060f720
RBP: 000000000060f720 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: ffff8800b5459b68 R12: ffff8800ce150e00
R13: 000000000060f720 R14: 00000000006127a8 R15: 0000000000000000
 padzero+0x1c/0x2b
 load_elf_binary+0x785/0xdc7
 search_binary_handler+0x81/0x1ff
 do_execveat_common.isra.14+0x600/0x888
 do_execve+0x1f/0x21
 SyS_execve+0x28/0x2f
 do_syscall_64+0x89/0x1be
 entry_SYSCALL64_slow_path+0x25/0x25
RIP: 0033:0x7fdb6009ee07
RSP: 002b:00007fff566d9728 EFLAGS: 00000246 ORIG_RAX: 000000000000003b
RAX: ffffffffffffffda RBX: 000055ba57280900 RCX: 00007fdb6009ee07
RDX: 000055ba5727f270 RSI: 000055ba5727cac0 RDI: 000055ba57280900
RBP: 000055ba57280900 R08: 00007fff566d9700 R09: 0000000000000000
R10: 000055ba5727cac0 R11: 0000000000000246 R12: 0000000000000000
R13: 000055ba5727cac0 R14: 000055ba5727f270 R15: 0000000000000000
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Fix IPv6 support in AF_RXRPC in the following ways:

 (1) When extracting the address from a received IPv4 packet, if the local
     transport socket is open for IPv6 then fill out the sockaddr_rxrpc
     struct for an IPv4-mapped-to-IPv6 AF_INET6 transport address instead
     of an AF_INET one.

 (2) When sending CHALLENGE or RESPONSE packets, the transport length needs
     to be set from the sockaddr_rxrpc::transport_len field rather than
     sizeof() on the IPv4 transport address.

 (3) When processing an IPv4 ICMP packet received by an IPv6 socket, set up
     the address correctly before searching for the affected peer.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

rxrpc_service_prealloc_one() doesn't set the socket pointer on any new call
it preallocates, but does add it to the rxrpc net namespace call list.
This, however, causes rxrpc_put_call() to oops when the call is discarded
when the socket is closed.  rxrpc_put_call() needs the socket to be able to
reach the namespace so that it can use a lock held therein.

Fix this by setting a call's socket pointer immediately before discarding
it.

This can be triggered by unloading the kafs module, resulting in an oops
like the following:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000030
IP: rxrpc_put_call+0x1e2/0x32d
PGD 0
P4D 0
Oops: 0000 [#1] SMP
Modules linked in: kafs(E-)
CPU: 3 PID: 3037 Comm: rmmod Tainted: G            E   4.12.0-fscache+ #213
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
task: ffff8803fc92e2c0 task.stack: ffff8803fef74000
RIP: 0010:rxrpc_put_call+0x1e2/0x32d
RSP: 0018:ffff8803fef77e08 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8803fab99ac0 RCX: 000000000000000f
RDX: ffffffff81c50a40 RSI: 000000000000000c RDI: ffff8803fc92ea88
RBP: ffff8803fef77e30 R08: ffff8803fc87b941 R09: ffffffff82946d20
R10: ffff8803fef77d10 R11: 00000000000076fc R12: 0000000000000005
R13: ffff8803fab99c20 R14: 0000000000000001 R15: ffffffff816c6aee
FS:  00007f915a059700(0000) GS:ffff88041fb80000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000030 CR3: 00000003fef39000 CR4: 00000000001406e0
Call Trace:
 rxrpc_discard_prealloc+0x325/0x341
 rxrpc_listen+0xf9/0x146
 kernel_listen+0xb/0xd
 afs_close_socket+0x3e/0x173 [kafs]
 afs_exit+0x1f/0x57 [kafs]
 SyS_delete_module+0x10f/0x19a
 do_syscall_64+0x8a/0x149
 entry_SYSCALL64_slow_path+0x25/0x25

Fixes: 2baec2c3 ("rxrpc: Support network namespacing")
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Cache the congestion window setting that was determined during a call's
transmission phase when it finishes so that it can be used by the next call
to the same peer, thereby shortcutting the slow-start algorithm.

The value is stored in the rxrpc_peer struct and is accessed without
locking.  Each call takes the value that happens to be there when it starts
and just overwrites the value when it finishes.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement AuriStor's service upgrade facility.  There are three problems
that this is meant to deal with:

 (1) Various of the standard AFS RPC calls have IPv4 addresses in their
     requests and/or replies - but there's no room for including IPv6
     addresses.

 (2) Definition of IPv6-specific RPC operations in the standard operation
     sets has not yet been achieved.

 (3) One could envision the creation a new service on the same port that as
     the original service.  The new service could implement improved
     operations - and the client could try this first, falling back to the
     original service if it's not there.

     Unfortunately, certain servers ignore packets addressed to a service
     they don't implement and don't respond in any way - not even with an
     ABORT.  This means that the client must then wait for the call timeout
     to occur.

What service upgrade does is to see if the connection is marked as being
'upgradeable' and if so, change the service ID in the server and thus the
request and reply formats.  Note that the upgrade isn't mandatory - a
server that supports only the original call set will ignore the upgrade
request.

In the protocol, the procedure is then as follows:

 (1) To request an upgrade, the first DATA packet in a new connection must
     have the userStatus set to 1 (this is normally 0).  The userStatus
     value is normally ignored by the server.

 (2) If the server doesn't support upgrading, the reply packets will
     contain the same service ID as for the first request packet.

 (3) If the server does support upgrading, all future reply packets on that
     connection will contain the new service ID and the new service ID will
     be applied to *all* further calls on that connection as well.

 (4) The RPC op used to probe the upgrade must take the same request data
     as the shadow call in the upgrade set (but may return a different
     reply).  GetCapability RPC ops were added to all standard sets for
     just this purpose.  Ops where the request formats differ cannot be
     used for probing.

 (5) The client must wait for completion of the probe before sending any
     further RPC ops to the same destination.  It should then use the
     service ID that recvmsg() reported back in all future calls.

 (6) The shadow service must have call definitions for all the operation
     IDs defined by the original service.


To support service upgrading, a server should:

 (1) Call bind() twice on its AF_RXRPC socket before calling listen().
     Each bind() should supply a different service ID, but the transport
     addresses must be the same.  This allows the server to receive
     requests with either service ID.

 (2) Enable automatic upgrading by calling setsockopt(), specifying
     RXRPC_UPGRADEABLE_SERVICE and passing in a two-member array of
     unsigned shorts as the argument:

	unsigned short optval[2];

     This specifies a pair of service IDs.  They must be different and must
     match the service IDs bound to the socket.  Member 0 is the service ID
     to upgrade from and member 1 is the service ID to upgrade to.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Permit bind() to be called on an AF_RXRPC socket more than once (currently
maximum twice) to bind multiple listening services to it.  There are some
restrictions:

 (1) All bind() calls involved must have a non-zero service ID.

 (2) The service IDs must all be different.

 (3) The rest of the address (notably the transport part) must be the same
     in all (a single UDP socket is shared).

 (4) This must be done before listen() or sendmsg() is called.

This allows someone to connect to the service socket with different service
IDs and lays the foundation for service upgrading.

The service ID used by an incoming call can be extracted from the msg_name
returned by recvmsg().
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Support network namespacing in AF_RXRPC with the following changes:

 (1) All the local endpoint, peer and call lists, locks, counters, etc. are
     moved into the per-namespace record.

 (2) All the connection tracking is moved into the per-namespace record
     with the exception of the client connection ID tree, which is kept
     global so that connection IDs are kept unique per-machine.

 (3) Each namespace gets its own epoch.  This allows each network namespace
     to pretend to be a separate client machine.

 (4) The /proc/net/rxrpc_xxx files are now called /proc/net/rxrpc/xxx and
     the contents reflect the namespace.

fs/afs/ should be okay with this patch as it explicitly requires the current
net namespace to be init_net to permit a mount to proceed at the moment.  It
will, however, need updating so that cells, IP addresses and DNS records are
per-namespace also.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use negative error codes in struct rxrpc_call::error because that's what
the kernel normally deals with and to make the code consistent.  We only
turn them positive when transcribing into a cmsg for userspace recvmsg.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

All the routines by which rxrpc is accessed from the outside are serialised
by means of the socket lock (sendmsg, recvmsg, bind,
rxrpc_kernel_begin_call(), ...) and this presents a problem:

 (1) If a number of calls on the same socket are in the process of
     connection to the same peer, a maximum of four concurrent live calls
     are permitted before further calls need to wait for a slot.

 (2) If a call is waiting for a slot, it is deep inside sendmsg() or
     rxrpc_kernel_begin_call() and the entry function is holding the socket
     lock.

 (3) sendmsg() and recvmsg() or the in-kernel equivalents are prevented
     from servicing the other calls as they need to take the socket lock to
     do so.

 (4) The socket is stuck until a call is aborted and makes its slot
     available to the waiter.

Fix this by:

 (1) Provide each call with a mutex ('user_mutex') that arbitrates access
     by the users of rxrpc separately for each specific call.

 (2) Make rxrpc_sendmsg() and rxrpc_recvmsg() unlock the socket as soon as
     they've got a call and taken its mutex.

     Note that I'm returning EWOULDBLOCK from recvmsg() if MSG_DONTWAIT is
     set but someone else has the lock.  Should I instead only return
     EWOULDBLOCK if there's nothing currently to be done on a socket, and
     sleep in this particular instance because there is something to be
     done, but we appear to be blocked by the interrupt handler doing its
     ping?

 (3) Make rxrpc_new_client_call() unlock the socket after allocating a new
     call, locking its user mutex and adding it to the socket's call tree.
     The call is returned locked so that sendmsg() can add data to it
     immediately.

     From the moment the call is in the socket tree, it is subject to
     access by sendmsg() and recvmsg() - even if it isn't connected yet.

 (4) Lock new service calls in the UDP data_ready handler (in
     rxrpc_new_incoming_call()) because they may already be in the socket's
     tree and the data_ready handler makes them live immediately if a user
     ID has already been preassigned.

     Note that the new call is locked before any notifications are sent
     that it is live, so doing mutex_trylock() *ought* to always succeed.
     Userspace is prevented from doing sendmsg() on calls that are in a
     too-early state in rxrpc_do_sendmsg().

 (5) Make rxrpc_new_incoming_call() return the call with the user mutex
     held so that a ping can be scheduled immediately under it.

     Note that it might be worth moving the ping call into
     rxrpc_new_incoming_call() and then we can drop the mutex there.

 (6) Make rxrpc_accept_call() take the lock on the call it is accepting and
     release the socket after adding the call to the socket's tree.  This
     is slightly tricky as we've dequeued the call by that point and have
     to requeue it.

     Note that requeuing emits a trace event.

 (7) Make rxrpc_kernel_send_data() and rxrpc_kernel_recv_data() take the
     new mutex immediately and don't bother with the socket mutex at all.

This patch has the nice bonus that calls on the same socket are now to some
extent parallelisable.

Note that we might want to move rxrpc_service_prealloc() calls out from the
socket lock and give it its own lock, so that we don't hang progress in
other calls because we're waiting for the allocator.

We probably also want to avoid calling rxrpc_notify_socket() from within
the socket lock (rxrpc_accept_call()).
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Tested-by: NMarc Dionne <marc.c.dionne@auristor.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Allow listen() with a backlog of 0 to be used to disable listening on an
AF_RXRPC socket.  This also releases any preallocation, thereby making it
easier for a kernel service to account for all allocated call structures
when shutting down the service.

The socket cannot thereafter have listening reenabled, but must rather be
closed and reopened.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Split rxrpc_send_data_packet() to separate ACK generation (which is more
complicated) from ABORT generation.  This simplifies the code a bit and
fixes the following warning:

In file included from ../net/rxrpc/output.c:20:0:
net/rxrpc/output.c: In function 'rxrpc_send_call_packet':
net/rxrpc/ar-internal.h:1187:27: error: 'top' may be used uninitialized in this function [-Werror=maybe-uninitialized]
net/rxrpc/output.c:103:24: note: 'top' was declared here
net/rxrpc/output.c:225:25: error: 'hard_ack' may be used uninitialized in this function [-Werror=maybe-uninitialized]
Reported-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NDavid Howells <dhowells@redhat.com>

If an call comes in to a local endpoint that isn't listening for any
incoming calls at the moment, an oops will happen.  We need to check that
the local endpoint's service pointer isn't NULL before we dereference it.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Reduce the rxrpc_local::services list to just a pointer as we don't permit
multiple service endpoints to bind to a single transport endpoints (this is
excluded by rxrpc_lookup_local()).

The reason we don't allow this is that if you send a request to an AFS
filesystem service, it will try to talk back to your cache manager on the
port you sent from (this is how file change notifications are handled).  To
prevent someone from stealing your CM callbacks, we don't let AF_RXRPC
sockets share a UDP socket if at least one of them has a service bound.
Signed-off-by: NDavid Howells <dhowells@redhat.com>

Add a tracepoint to follow the life of packets that get added to a call's
receive buffer.
Signed-off-by: NDavid Howells <dhowells@redhat.com>