linux/net
James Chapman d02ba2a611 l2tp: fix race in pppol2tp_release with session object destroy
pppol2tp_release uses call_rcu to put the final ref on its socket. But
the session object doesn't hold a ref on the session socket so may be
freed while the pppol2tp_put_sk RCU callback is scheduled. Fix this by
having the session hold a ref on its socket until the session is
destroyed. It is this ref that is dropped via call_rcu.

Sessions are also deleted via l2tp_tunnel_closeall. This must now also put
the final ref via call_rcu. So move the call_rcu call site into
pppol2tp_session_close so that this happens in both destroy paths. A
common destroy path should really be implemented, perhaps with
l2tp_tunnel_closeall calling l2tp_session_delete like pppol2tp_release
does, but this will be looked at later.

ODEBUG: activate active (active state 1) object type: rcu_head hint:           (null)
WARNING: CPU: 3 PID: 13407 at lib/debugobjects.c:291 debug_print_object+0x166/0x220
Modules linked in:
CPU: 3 PID: 13407 Comm: syzbot_19c09769 Not tainted 4.16.0-rc2+ #38
Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
RIP: 0010:debug_print_object+0x166/0x220
RSP: 0018:ffff880013647a00 EFLAGS: 00010082
RAX: dffffc0000000008 RBX: 0000000000000003 RCX: ffffffff814d3333
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff88001a59f6d0
RBP: ffff880013647a40 R08: 0000000000000000 R09: 0000000000000001
R10: ffff8800136479a8 R11: 0000000000000000 R12: 0000000000000001
R13: ffffffff86161420 R14: ffffffff85648b60 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88001a580000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020e77000 CR3: 0000000006022000 CR4: 00000000000006e0
Call Trace:
 debug_object_activate+0x38b/0x530
 ? debug_object_assert_init+0x3b0/0x3b0
 ? __mutex_unlock_slowpath+0x85/0x8b0
 ? pppol2tp_session_destruct+0x110/0x110
 __call_rcu.constprop.66+0x39/0x890
 ? __call_rcu.constprop.66+0x39/0x890
 call_rcu_sched+0x17/0x20
 pppol2tp_release+0x2c7/0x440
 ? fcntl_setlk+0xca0/0xca0
 ? sock_alloc_file+0x340/0x340
 sock_release+0x92/0x1e0
 sock_close+0x1b/0x20
 __fput+0x296/0x6e0
 ____fput+0x1a/0x20
 task_work_run+0x127/0x1a0
 do_exit+0x7f9/0x2ce0
 ? SYSC_connect+0x212/0x310
 ? mm_update_next_owner+0x690/0x690
 ? up_read+0x1f/0x40
 ? __do_page_fault+0x3c8/0xca0
 do_group_exit+0x10d/0x330
 ? do_group_exit+0x330/0x330
 SyS_exit_group+0x22/0x30
 do_syscall_64+0x1e0/0x730
 ? trace_hardirqs_off_thunk+0x1a/0x1c
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x7f362e471259
RSP: 002b:00007ffe389abe08 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f362e471259
RDX: 00007f362e471259 RSI: 000000000000002e RDI: 0000000000000000
RBP: 00007ffe389abe30 R08: 0000000000000000 R09: 00007f362e944270
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000400b60
R13: 00007ffe389abf50 R14: 0000000000000000 R15: 0000000000000000
Code: 8d 3c dd a0 8f 64 85 48 89 fa 48 c1 ea 03 80 3c 02 00 75 7b 48 8b 14 dd a0 8f 64 85 4c 89 f6 48 c7 c7 20 85 64 85 e
8 2a 55 14 ff <0f> 0b 83 05 ad 2a 68 04 01 48 83 c4 18 5b 41 5c 41 5d 41 5e 41

Fixes: ee40fb2e1e ("l2tp: protect sock pointer of struct pppol2tp_session with RCU")
Signed-off-by: James Chapman <jchapman@katalix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2018-02-26 12:20:36 -05:00
..
6lowpan License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
9p virtio: bugfixes 2018-02-15 14:29:27 -08:00
802 treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
8021q net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
appletalk net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
atm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
ax25 net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
batman-adv vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
bluetooth vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
bpf bpf: fix null pointer deref in bpf_prog_test_run_xdp 2018-02-01 07:43:56 -08:00
bridge Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2018-02-21 14:49:55 -05:00
caif vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
can can: migrate documentation to restructured text 2018-01-26 10:46:44 +01:00
ceph libceph: check kstrndup() return value 2018-01-29 18:36:12 +01:00
core net_sched: gen_estimator: fix broken estimators based on percpu stats 2018-02-23 12:35:46 -05:00
dcb
dccp vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
decnet dn_getsockoptdecnet: move nf_{get/set}sockopt outside sock lock 2018-02-16 15:46:15 -05:00
dns_resolver afs: Support the AFS dynamic root 2018-02-06 14:43:37 +00:00
dsa net: dsa: Support internal phy on 'cpu' port 2018-01-23 19:22:38 -05:00
ethernet
hsr net: hsr: Convert timers to use timer_setup() 2017-10-25 13:00:27 +09:00
ieee802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
ife MAINTAINERS: Update Yotam's E-mail 2017-11-01 12:19:03 +09:00
ipv4 net: ipv4: Set addr_type in hash_keys for forwarded case 2018-02-22 14:30:51 -05:00
ipv6 ipv6 sit: work around bogus gcc-8 -Wrestrict warning 2018-02-23 10:53:26 -05:00
iucv vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
kcm vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
key af_key: Fix memory leak in key_notify_policy. 2018-01-10 09:45:11 +01:00
l2tp l2tp: fix race in pppol2tp_release with session object destroy 2018-02-26 12:20:36 -05:00
l3mdev
lapb treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts 2017-11-21 16:35:54 -08:00
llc net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
mac80211 Various fixes across the tree, the shortlog basically says it all: 2018-02-22 15:17:01 -05:00
mac802154 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00
mpls mpls, nospec: Sanitize array index in mpls_label_ok() 2018-02-08 15:24:12 -05:00
ncsi net/ncsi: Don't take any action on HNCDSC AEN 2017-12-18 14:50:11 -05:00
netfilter netfilter: IDLETIMER: be syzkaller friendly 2018-02-19 18:28:59 +01:00
netlabel net/netlabel: Add list_next_rcu() in rcu_dereference(). 2017-11-18 10:32:41 +09:00
netlink netlink: put module reference if dump start fails 2018-02-22 14:01:38 -05:00
netrom net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
nfc NFC: llcp: Limit size of SDP URI 2018-02-16 15:16:05 -05:00
nsh openvswitch: enable NSH support 2017-11-08 16:12:33 +09:00
openvswitch openvswitch: Remove padding from packet before L3+ conntrack processing 2018-02-01 09:46:22 -05:00
packet vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
phonet vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
psample MAINTAINERS: Update Yotam's E-mail 2017-11-01 12:19:03 +09:00
qrtr net: use rtnl_register_module where needed 2017-12-04 11:32:39 -05:00
rds rds: do not call ->conn_alloc with GFP_KERNEL 2018-02-13 13:52:02 -05:00
rfkill vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
rose net: delete /proc THIS_MODULE references 2018-01-16 15:01:33 -05:00
rxrpc rxrpc: Fix send in rxrpc_send_data_packet() 2018-02-22 15:37:47 -05:00
sched net: sched: report if filter is too large to dump 2018-02-20 21:57:17 -05:00
sctp sctp: remove the left unnecessary check for chunk in sctp_renege_events 2018-02-16 16:32:37 -05:00
smc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
strparser strparser: Call sock_owned_by_user_nocheck 2017-12-28 14:28:22 -05:00
sunrpc vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
switchdev net: bridge: Add/del switchdev object on host join/leave 2017-11-10 13:41:40 +09:00
tipc tipc: Fix missing RTNL lock protection during setting link properties 2018-02-14 14:46:33 -05:00
tls tls: getsockopt return record sequence number 2018-02-14 15:05:19 -05:00
unix net: af_unix: fix typo in UNIX_SKB_FRAGS_SZ comment 2018-02-13 12:21:45 -05:00
vmw_vsock vfs: do bulk POLL* -> EPOLL* replacement 2018-02-11 14:34:03 -08:00
wimax License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
wireless Various fixes across the tree, the shortlog basically says it all: 2018-02-22 15:17:01 -05:00
x25 treewide: Remove TIMER_FUNC_TYPE and TIMER_DATA_TYPE casts 2017-11-21 16:35:54 -08:00
xfrm Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next 2018-01-26 10:22:53 -05:00
compat.c
Kconfig Staging/IIO patches for 4.16-rc1 2018-02-01 09:51:57 -08:00
Makefile ipx: move Novell IPX protocol support into staging 2017-11-28 13:55:00 +01:00
socket.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-01-31 14:31:10 -08:00
sysctl_net.c