| From 45add7af73dc5673589d8af45d92ab46a5c388d9 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Mon, 4 Apr 2022 11:34:39 -0700 |
| Subject: rxrpc: fix a race in rxrpc_exit_net() |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| [ Upstream commit 1946014ca3b19be9e485e780e862c375c6f98bad ] |
| |
| 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: |
| <TASK> |
| __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 |
| </TASK> |
| |
| Fixes: ace45bec6d77 ("rxrpc: Fix firewall route keepalive") |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Cc: David Howells <dhowells@redhat.com> |
| Cc: Marc Dionne <marc.dionne@auristor.com> |
| Cc: linux-afs@lists.infradead.org |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/rxrpc/net_ns.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| diff --git a/net/rxrpc/net_ns.c b/net/rxrpc/net_ns.c |
| index 25bbc4cc8b13..f15d6942da45 100644 |
| --- a/net/rxrpc/net_ns.c |
| +++ b/net/rxrpc/net_ns.c |
| @@ -113,8 +113,8 @@ static __net_exit void rxrpc_exit_net(struct net *net) |
| struct rxrpc_net *rxnet = rxrpc_net(net); |
| |
| rxnet->live = false; |
| - del_timer_sync(&rxnet->peer_keepalive_timer); |
| cancel_work_sync(&rxnet->peer_keepalive_work); |
| + del_timer_sync(&rxnet->peer_keepalive_timer); |
| rxrpc_destroy_all_calls(rxnet); |
| rxrpc_destroy_all_connections(rxnet); |
| rxrpc_destroy_all_peers(rxnet); |
| -- |
| 2.35.1 |
| |