Eric Dumazet 032be5f19a rxrpc: fix race condition in rxrpc_input_packet() ... After commit 5271953cad ("rxrpc: Use the UDP encap_rcv hook"), rxrpc_input_packet() is directly called from lockless UDP receive path, under rcu_read_lock() protection. It must therefore use RCU rules : - udp_sk->sk_user_data can be cleared at any point in this function. rcu_dereference_sk_user_data() is what we need here. - Also, since sk_user_data might have been set in rxrpc_open_socket() we must observe a proper RCU grace period before kfree(local) in rxrpc_lookup_local() v4: @local can be NULL in xrpc_lookup_local() as reported by kbuild test robot <lkp@intel.com> and Julia Lawall <julia.lawall@lip6.fr>, thanks ! v3,v2 : addressed David Howells feedback, thanks ! syzbot reported : kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [#1] PREEMPT SMP KASAN CPU: 0 PID: 19236 Comm: syz-executor703 Not tainted 5.1.0-rc6 #79 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0xbef/0x3fb0 kernel/locking/lockdep.c:3573 Code: 00 0f 85 a5 1f 00 00 48 81 c4 10 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 4a 21 00 00 49 81 7d 00 20 54 9c 89 0f 84 cf f4 RSP: 0018:ffff88809d7aef58 EFLAGS: 00010002 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000026 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff88809d7af090 R08: 0000000000000001 R09: 0000000000000001 R10: ffffed1015d05bc7 R11: ffff888089428600 R12: 0000000000000000 R13: 0000000000000130 R14: 0000000000000001 R15: 0000000000000001 FS: 00007f059044d700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004b6040 CR3: 00000000955ca000 CR4: 00000000001406f0 Call Trace: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 skb_queue_tail+0x26/0x150 net/core/skbuff.c:2972 rxrpc_reject_packet net/rxrpc/input.c:1126 [inline] rxrpc_input_packet+0x4a0/0x5536 net/rxrpc/input.c:1414 udp_queue_rcv_one_skb+0xaf2/0x1780 net/ipv4/udp.c:2011 udp_queue_rcv_skb+0x128/0x730 net/ipv4/udp.c:2085 udp_unicast_rcv_skb.isra.0+0xb9/0x360 net/ipv4/udp.c:2245 __udp4_lib_rcv+0x701/0x2ca0 net/ipv4/udp.c:2301 udp_rcv+0x22/0x30 net/ipv4/udp.c:2482 ip_protocol_deliver_rcu+0x60/0x8f0 net/ipv4/ip_input.c:208 ip_local_deliver_finish+0x23b/0x390 net/ipv4/ip_input.c:234 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:255 dst_input include/net/dst.h:450 [inline] ip_rcv_finish+0x1e1/0x300 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0x115/0x1a0 net/core/dev.c:4987 __netif_receive_skb+0x2c/0x1c0 net/core/dev.c:5099 netif_receive_skb_internal+0x117/0x660 net/core/dev.c:5202 napi_frags_finish net/core/dev.c:5769 [inline] napi_gro_frags+0xade/0xd10 net/core/dev.c:5843 tun_get_user+0x2f24/0x3fb0 drivers/net/tun.c:1981 tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2027 call_write_iter include/linux/fs.h:1866 [inline] do_iter_readv_writev+0x5e1/0x8e0 fs/read_write.c:681 do_iter_write fs/read_write.c:957 [inline] do_iter_write+0x184/0x610 fs/read_write.c:938 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1002 do_writev+0x15e/0x370 fs/read_write.c:1037 __do_sys_writev fs/read_write.c:1110 [inline] __se_sys_writev fs/read_write.c:1107 [inline] __x64_sys_writev+0x75/0xb0 fs/read_write.c:1107 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 5271953cad ("rxrpc: Use the UDP encap_rcv hook") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2019-04-24 14:05:09 -07:00
..
af_rxrpc.c	rxrpc: Make rxrpc_kernel_check_life() indicate if call completed	2019-04-12 16:57:23 -07:00
ar-internal.h	rxrpc: Fix detection of out of order acks	2019-04-12 16:57:23 -07:00
call_accept.c	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net	2018-10-19 11:03:06 -07:00
call_event.c	rxrpc: Fix lockup due to no error backoff after ack transmit error	2018-11-02 23:59:26 -07:00
call_object.c	Revert "rxrpc: Allow failed client calls to be retried"	2019-01-15 21:33:36 -08:00
conn_client.c	rxrpc: Fix client call queueing, waiting for channel	2019-03-08 18:24:53 -08:00
conn_event.c	rxrpc: Trace received connection aborts	2019-04-12 16:57:23 -07:00
conn_object.c	rxrpc: Drop the local endpoint arg from rxrpc_extract_addr_from_skb()	2018-10-04 09:32:28 +01:00
conn_service.c	rxrpc: Fix apparent leak of rxrpc_local objects	2018-03-30 21:05:33 +01:00
input.c	rxrpc: fix race condition in rxrpc_input_packet()	2019-04-24 14:05:09 -07:00
insecure.c	rxrpc: Trace protocol errors in received packets	2017-04-06 11:09:39 +01:00
Kconfig	rxrpc: Add config to inject packet loss	2016-09-17 11:24:04 +01:00
key.c	rxrpc: Use correct timestamp from Kerberos 5 ticket	2017-08-29 10:55:06 +01:00
local_event.c	rxrpc: Drop the local endpoint arg from rxrpc_extract_addr_from_skb()	2018-10-04 09:32:28 +01:00
local_object.c	rxrpc: fix race condition in rxrpc_input_packet()	2019-04-24 14:05:09 -07:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
misc.c	rxrpc: Fix call timeouts	2017-11-24 10:18:41 +00:00
net_ns.c	rxrpc: Add /proc/net/rxrpc/peers to display peer list	2018-10-15 22:52:58 -07:00
output.c	rxrpc: avoid clang -Wuninitialized warning	2019-03-23 21:48:30 -04:00
peer_event.c	rxrpc: Clear socket error	2019-04-12 16:57:23 -07:00
peer_object.c	rxrpc: Fix the packet reception routine	2018-10-08 22:42:04 +01:00
proc.c	rxrpc: Add /proc/net/rxrpc/peers to display peer list	2018-10-15 22:52:58 -07:00
protocol.h	rxrpc: Improve up-front incoming packet checking	2018-09-28 10:32:31 +01:00
recvmsg.c	rxrpc: bad unlock balance in rxrpc_recvmsg	2019-02-06 10:54:07 -08:00
rxkad.c	rxrpc: Remove VLA usage of skcipher	2018-09-28 12:46:07 +08:00
security.c	rxrpc: remove unused static variables	2018-03-30 21:04:44 +01:00
sendmsg.c	rxrpc: Allow errors to be returned from rxrpc_queue_packet()	2019-04-12 16:57:23 -07:00
skbuff.c	rxrpc: Use rxrpc_free_skb() rather than rxrpc_lose_skb()	2018-10-04 09:32:27 +01:00
sysctl.c	rxrpc: remove redundant static int 'zero'	2018-08-11 11:25:18 -07:00
utils.c	rxrpc: Drop the local endpoint arg from rxrpc_extract_addr_from_skb()	2018-10-04 09:32:28 +01:00