linux.git/net/rxrpc/net_ns.c, branch vm-bind

rxrpc: Fix locking issue

2022-05-22T20:03:01+00:00

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); 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: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both") Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller

rxrpc: Allow list of in-use local UDP endpoints to be viewed in /proc

2022-05-22T20:03:01+00:00

Allow the list of in-use local UDP endpoints in the current network namespace to be viewed in /proc. To aid with this, the endpoint list is converted to an hlist and RCU-safe manipulation is used so that the list can be read with only the RCU read lock held. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: David S. Miller

rxrpc: Restore removed timer deletion

2022-04-15T09:54:49+00:00

A recent patch[1] from Eric Dumazet flipped the order in which the keepalive timer and the keepalive worker were cancelled in order to fix a syzbot reported issue[2]. Unfortunately, this enables the mirror image bug whereby the timer races with rxrpc_exit_net(), restarting the worker after it has been cancelled: CPU 1 CPU 2 =============== ===================== if (rxnet->live) rxnet->live = false; cancel_work_sync(&rxnet->peer_keepalive_work); rxrpc_queue_work(&rxnet->peer_keepalive_work); del_timer_sync(&rxnet->peer_keepalive_timer); Fix this by restoring the removed del_timer_sync() so that we try to remove the timer twice. If the timer runs again, it should see ->live == false and not restart the worker. Fixes: 1946014ca3b1 ("rxrpc: fix a race in rxrpc_exit_net()") Signed-off-by: David Howells cc: Eric Dumazet cc: Marc Dionne cc: linux-afs@lists.infradead.org Link: https://lore.kernel.org/r/20220404183439.3537837-1-eric.dumazet@gmail.com/ [1] Link: https://syzkaller.appspot.com/bug?extid=724378c4bb58f703b09a [2] Reviewed-by: Eric Dumazet Signed-off-by: David S. Miller

rxrpc: fix a race in rxrpc_exit_net()

2022-04-06T12:48:51+00:00

Current code can lead to the following race: CPU0 CPU1 rxrpc_exit_net() rxrpc_peer_keepalive_worker() if (rxnet->live) rxnet->live = false; del_timer_sync(&rxnet->peer_keepalive_timer); timer_reduce(&rxnet->peer_keepalive_timer, jiffies + delay); cancel_work_sync(&rxnet->peer_keepalive_work); rxrpc_exit_net() exits while peer_keepalive_timer is still armed, leading to use-after-free. syzbot report was: ODEBUG: free active (active state 0) object type: timer_list hint: rxrpc_peer_keepalive_timeout+0x0/0xb0 WARNING: CPU: 0 PID: 3660 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505 Modules linked in: CPU: 0 PID: 3660 Comm: kworker/u4:6 Not tainted 5.17.0-syzkaller-13993-g88e6c0207623 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: netns cleanup_net RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505 Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 af 00 00 00 48 8b 14 dd 00 1c 26 8a 4c 89 ee 48 c7 c7 00 10 26 8a e8 b1 e7 28 05 <0f> 0b 83 05 15 eb c5 09 01 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e c3 RSP: 0018:ffffc9000353fb00 EFLAGS: 00010082 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: ffff888029196140 RSI: ffffffff815efad8 RDI: fffff520006a7f52 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815ea4ae R11: 0000000000000000 R12: ffffffff89ce23e0 R13: ffffffff8a2614e0 R14: ffffffff816628c0 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe1f2908924 CR3: 0000000043720000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __debug_check_no_obj_freed lib/debugobjects.c:992 [inline] debug_check_no_obj_freed+0x301/0x420 lib/debugobjects.c:1023 kfree+0xd6/0x310 mm/slab.c:3809 ops_free_list.part.0+0x119/0x370 net/core/net_namespace.c:176 ops_free_list net/core/net_namespace.c:174 [inline] cleanup_net+0x591/0xb00 net/core/net_namespace.c:598 process_one_work+0x996/0x1610 kernel/workqueue.c:2289 worker_thread+0x665/0x1080 kernel/workqueue.c:2436 kthread+0x2e9/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298 Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive") Signed-off-by: Eric Dumazet Cc: David Howells Cc: Marc Dionne Cc: linux-afs@lists.infradead.org Reported-by: syzbot Signed-off-by: David S. Miller

rxrpc: Rewrite the client connection manager

2020-09-08T20:11:43+00:00

Rewrite the rxrpc client connection manager so that it can support multiple connections for a given security key to a peer. The following changes are made: (1) For each open socket, the code currently maintains an rbtree with the connections placed into it, keyed by communications parameters. This is tricky to maintain as connections can be culled from the tree or replaced within it. Connections can require replacement for a number of reasons, e.g. their IDs span too great a range for the IDR data type to represent efficiently, the call ID numbers on that conn would overflow or the conn got aborted. This is changed so that there's now a connection bundle object placed in the tree, keyed on the same parameters. The bundle, however, does not need to be replaced. (2) An rxrpc_bundle object can now manage the available channels for a set of parallel connections. The lock that manages this is moved there from the rxrpc_connection struct (channel_lock). (3) There'a a dummy bundle for all incoming connections to share so that they have a channel_lock too. It might be better to give each incoming connection its own bundle. This bundle is not needed to manage which channels incoming calls are made on because that's the solely at whim of the client. (4) The restrictions on how many client connections are around are removed. Instead, a previous patch limits the number of client calls that can be allocated. Ordinarily, client connections are reaped after 2 minutes on the idle queue, but when more than a certain number of connections are in existence, the reaper starts reaping them after 2s of idleness instead to get the numbers back down. It could also be made such that new call allocations are forced to wait until the number of outstanding connections subsides. Signed-off-by: David Howells

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 36

2019-05-24T15:27:11+00:00

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 licence as published by the free software foundation either version 2 of the licence 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 114 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Kate Stewart Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170857.552531963@linutronix.de Signed-off-by: Greg Kroah-Hartman

rxrpc: Add /proc/net/rxrpc/peers to display peer list

2018-10-16T05:52:58+00:00

Add /proc/net/rxrpc/peers to display the list of peers currently active. Signed-off-by: David Howells Signed-off-by: David S. Miller

rxrpc: Fix the keepalive generator [ver #2]

2018-08-09T02:10:26+00:00

AF_RXRPC has a keepalive message generator that generates a message for a peer ~20s after the last transmission to that peer to keep firewall ports open. The implementation is incorrect in the following ways: (1) It mixes up ktime_t and time64_t types. (2) It uses ktime_get_real(), the output of which may jump forward or backward due to adjustments to the time of day. (3) If the current time jumps forward too much or jumps backwards, the generator function will crank the base of the time ring round one slot at a time (ie. a 1s period) until it catches up, spewing out VERSION packets as it goes. Fix the problem by: (1) Only using time64_t. There's no need for sub-second resolution. (2) Use ktime_get_seconds() rather than ktime_get_real() so that time isn't perceived to go backwards. (3) Simplifying rxrpc_peer_keepalive_worker() by splitting it into two parts: (a) The "worker" function that manages the buckets and the timer. (b) The "dispatch" function that takes the pending peers and potentially transmits a keepalive packet before putting them back in the ring into the slot appropriate to the revised last-Tx time. (4) Taking everything that's pending out of the ring and splicing it into a temporary collector list for processing. In the case that there's been a significant jump forward, the ring gets entirely emptied and then the time base can be warped forward before the peers are processed. The warping can't happen if the ring isn't empty because the slot a peer is in is keepalive-time dependent, relative to the base time. (5) Limit the number of iterations of the bucket array when scanning it. (6) Set the timer to skip any empty slots as there's no point waking up if there's nothing to do yet. This can be triggered by an incoming call from a server after a reboot with AF_RXRPC and AFS built into the kernel causing a peer record to be set up before userspace is started. The system clock is then adjusted by userspace, thereby potentially causing the keepalive generator to have a meltdown - which leads to a message like: watchdog: BUG: soft lockup - CPU#0 stuck for 23s! [kworker/0:1:23] ... Workqueue: krxrpcd rxrpc_peer_keepalive_worker EIP: lock_acquire+0x69/0x80 ... Call Trace: ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? _raw_spin_lock_bh+0x29/0x60 ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? rxrpc_peer_keepalive_worker+0x5e/0x350 ? __lock_acquire+0x3d3/0x870 ? process_one_work+0x110/0x340 ? process_one_work+0x166/0x340 ? process_one_work+0x110/0x340 ? worker_thread+0x39/0x3c0 ? kthread+0xdb/0x110 ? cancel_delayed_work+0x90/0x90 ? kthread_stop+0x70/0x70 ? ret_from_fork+0x19/0x24 Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive") Reported-by: kernel test robot Signed-off-by: David Howells Signed-off-by: David S. Miller

proc: introduce proc_create_net{,_data}

2018-05-16T05:24:30+00:00

Variants of proc_create{,_data} that directly take a struct seq_operations and deal with network namespaces in ->open and ->release. All callers of proc_create + seq_open_net converted over, and seq_{open,release}_net are removed entirely. Signed-off-by: Christoph Hellwig

rxrpc: Fix leak of rxrpc_peer objects

2018-03-30T20:05:44+00:00

When a new client call is requested, an rxrpc_conn_parameters struct object is passed in with a bunch of parameters set, such as the local endpoint to use. A pointer to the target peer record is also placed in there by rxrpc_get_client_conn() - and this is removed if and only if a new connection object is allocated. Thus it leaks if a new connection object isn't allocated. Fix this by putting any peer object attached to the rxrpc_conn_parameters object in the function that allocated it. Fixes: 19ffa01c9c45 ("rxrpc: Use structs to hold connection params and protocol info") Signed-off-by: David Howells