linux-stable.git/net, branch v4.16.7 Linux kernel stable tree libceph: validate con->state at the top of try_write() 2018-05-01T19:47:27+00:00 Ilya Dryomov idryomov@gmail.com 2018-04-24T17:10:55+00:00 f23c684d479175af0b594d76d49f818ce8e48067 commit 9c55ad1c214d9f8c4594ac2c3fa392c1c32431a7 upstream. ceph_con_workfn() validates con->state before calling try_read() and then try_write(). However, try_read() temporarily releases con->mutex, notably in process_message() and ceph_con_in_msg_alloc(), opening the window for ceph_con_close() to sneak in, close the connection and release con->sock. When try_write() is called on the assumption that con->state is still valid (i.e. not STANDBY or CLOSED), a NULL sock gets passed to the networking stack: BUG: unable to handle kernel NULL pointer dereference at 0000000000000020 IP: selinux_socket_sendmsg+0x5/0x20 Make sure con->state is valid at the top of try_write() and add an explicit BUG_ON for this, similar to try_read(). Cc: stable@vger.kernel.org Link: https://tracker.ceph.com/issues/23706 Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Jason Dillaman <dillaman@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 9c55ad1c214d9f8c4594ac2c3fa392c1c32431a7 upstream.

ceph_con_workfn() validates con->state before calling try_read() and
then try_write().  However, try_read() temporarily releases con->mutex,
notably in process_message() and ceph_con_in_msg_alloc(), opening the
window for ceph_con_close() to sneak in, close the connection and
release con->sock.  When try_write() is called on the assumption that
con->state is still valid (i.e. not STANDBY or CLOSED), a NULL sock
gets passed to the networking stack:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
  IP: selinux_socket_sendmsg+0x5/0x20

Make sure con->state is valid at the top of try_write() and add an
explicit BUG_ON for this, similar to try_read().

Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/23706
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: reschedule a tick in finish_hunting() 2018-05-01T19:47:27+00:00 Ilya Dryomov idryomov@gmail.com 2018-04-23T13:25:10+00:00 9f2fae5c9d7845c65a8822b4e2175223fbfb8873 commit 7b4c443d139f1d2b5570da475f7a9cbcef86740c upstream. If we go without an established session for a while, backoff delay will climb to 30 seconds. The keepalive timeout is also 30 seconds, so it's pretty easily hit after a prolonged hunting for a monitor: we don't get a chance to send out a keepalive in time, which means we never get back a keepalive ack in time, cutting an established session and attempting to connect to a different monitor every 30 seconds: [Sun Apr 1 23:37:05 2018] libceph: mon0 10.80.20.99:6789 session established [Sun Apr 1 23:37:36 2018] libceph: mon0 10.80.20.99:6789 session lost, hunting for new mon [Sun Apr 1 23:37:36 2018] libceph: mon2 10.80.20.103:6789 session established [Sun Apr 1 23:38:07 2018] libceph: mon2 10.80.20.103:6789 session lost, hunting for new mon [Sun Apr 1 23:38:07 2018] libceph: mon1 10.80.20.100:6789 session established [Sun Apr 1 23:38:37 2018] libceph: mon1 10.80.20.100:6789 session lost, hunting for new mon [Sun Apr 1 23:38:37 2018] libceph: mon2 10.80.20.103:6789 session established [Sun Apr 1 23:39:08 2018] libceph: mon2 10.80.20.103:6789 session lost, hunting for new mon The regular keepalive interval is 10 seconds. After ->hunting is cleared in finish_hunting(), call __schedule_delayed() to ensure we send out a keepalive after 10 seconds. Cc: stable@vger.kernel.org # 4.7+ Link: http://tracker.ceph.com/issues/23537 Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Jason Dillaman <dillaman@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 7b4c443d139f1d2b5570da475f7a9cbcef86740c upstream.

If we go without an established session for a while, backoff delay will
climb to 30 seconds.  The keepalive timeout is also 30 seconds, so it's
pretty easily hit after a prolonged hunting for a monitor: we don't get
a chance to send out a keepalive in time, which means we never get back
a keepalive ack in time, cutting an established session and attempting
to connect to a different monitor every 30 seconds:

  [Sun Apr 1 23:37:05 2018] libceph: mon0 10.80.20.99:6789 session established
  [Sun Apr 1 23:37:36 2018] libceph: mon0 10.80.20.99:6789 session lost, hunting for new mon
  [Sun Apr 1 23:37:36 2018] libceph: mon2 10.80.20.103:6789 session established
  [Sun Apr 1 23:38:07 2018] libceph: mon2 10.80.20.103:6789 session lost, hunting for new mon
  [Sun Apr 1 23:38:07 2018] libceph: mon1 10.80.20.100:6789 session established
  [Sun Apr 1 23:38:37 2018] libceph: mon1 10.80.20.100:6789 session lost, hunting for new mon
  [Sun Apr 1 23:38:37 2018] libceph: mon2 10.80.20.103:6789 session established
  [Sun Apr 1 23:39:08 2018] libceph: mon2 10.80.20.103:6789 session lost, hunting for new mon

The regular keepalive interval is 10 seconds.  After ->hunting is
cleared in finish_hunting(), call __schedule_delayed() to ensure we
send out a keepalive after 10 seconds.

Cc: stable@vger.kernel.org # 4.7+
Link: http://tracker.ceph.com/issues/23537
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
libceph: un-backoff on tick when we have a authenticated session 2018-05-01T19:47:27+00:00 Ilya Dryomov idryomov@gmail.com 2018-04-23T13:25:10+00:00 acd10bf085b5a3187fd0298f5af1df23662b3b9a commit facb9f6eba3df4e8027301cc0e514dc582a1b366 upstream. This means that if we do some backoff, then authenticate, and are healthy for an extended period of time, a subsequent failure won't leave us starting our hunting sequence with a large backoff. Mirrors ceph.git commit d466bc6e66abba9b464b0b69687cf45c9dccf383. Cc: stable@vger.kernel.org # 4.7+ Signed-off-by: Ilya Dryomov <idryomov@gmail.com> Reviewed-by: Jason Dillaman <dillaman@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit facb9f6eba3df4e8027301cc0e514dc582a1b366 upstream.

This means that if we do some backoff, then authenticate, and are
healthy for an extended period of time, a subsequent failure won't
leave us starting our hunting sequence with a large backoff.

Mirrors ceph.git commit d466bc6e66abba9b464b0b69687cf45c9dccf383.

Cc: stable@vger.kernel.org # 4.7+
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
VSOCK: make af_vsock.ko removable again 2018-04-29T09:35:49+00:00 Stefan Hajnoczi stefanha@redhat.com 2018-04-17T06:25:58+00:00 8a92bcf2d4d86cfb3399fa35e4b06060404d80eb [ Upstream commit 05e489b1596f0aa1025a1fa572676631cd9665da ] Commit c1eef220c1760762753b602c382127bfccee226d ("vsock: always call vsock_init_tables()") introduced a module_init() function without a corresponding module_exit() function. Modules with an init function can only be removed if they also have an exit function. Therefore the vsock module was considered "permanent" and could not be removed. This patch adds an empty module_exit() function so that "rmmod vsock" works. No explicit cleanup is required because: 1. Transports call vsock_core_exit() upon exit and cannot be removed while sockets are still alive. 2. vsock_diag.ko does not perform any action that requires cleanup by vsock.ko. Fixes: c1eef220c176 ("vsock: always call vsock_init_tables()") Reported-by: Xiumei Mu <xmu@redhat.com> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Jorgen Hansen <jhansen@vmware.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Jorgen Hansen <jhansen@vmware.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 05e489b1596f0aa1025a1fa572676631cd9665da ]

Commit c1eef220c1760762753b602c382127bfccee226d ("vsock: always call
vsock_init_tables()") introduced a module_init() function without a
corresponding module_exit() function.

Modules with an init function can only be removed if they also have an
exit function.  Therefore the vsock module was considered "permanent"
and could not be removed.

This patch adds an empty module_exit() function so that "rmmod vsock"
works.  No explicit cleanup is required because:

1. Transports call vsock_core_exit() upon exit and cannot be removed
   while sockets are still alive.
2. vsock_diag.ko does not perform any action that requires cleanup by
   vsock.ko.

Fixes: c1eef220c176 ("vsock: always call vsock_init_tables()")
Reported-by: Xiumei Mu <xmu@redhat.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Jorgen Hansen <jhansen@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net: validate attribute sizes in neigh_dump_table() 2018-04-29T09:35:49+00:00 Eric Dumazet edumazet@google.com 2018-04-11T21:46:00+00:00 8ad6731df5b2f3112624b86b6140a9bcd0c3e44d [ Upstream commit 7dd07c143a4b54d050e748bee4b4b9e94a7b1744 ] Since neigh_dump_table() calls nlmsg_parse() without giving policy constraints, attributes can have arbirary size that we must validate Reported by syzbot/KMSAN : BUG: KMSAN: uninit-value in neigh_master_filtered net/core/neighbour.c:2292 [inline] BUG: KMSAN: uninit-value in neigh_dump_table net/core/neighbour.c:2348 [inline] BUG: KMSAN: uninit-value in neigh_dump_info+0x1af0/0x2250 net/core/neighbour.c:2438 CPU: 1 PID: 3575 Comm: syzkaller268891 Not tainted 4.16.0+ #83 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676 neigh_master_filtered net/core/neighbour.c:2292 [inline] neigh_dump_table net/core/neighbour.c:2348 [inline] neigh_dump_info+0x1af0/0x2250 net/core/neighbour.c:2438 netlink_dump+0x9ad/0x1540 net/netlink/af_netlink.c:2225 __netlink_dump_start+0x1167/0x12a0 net/netlink/af_netlink.c:2322 netlink_dump_start include/linux/netlink.h:214 [inline] rtnetlink_rcv_msg+0x1435/0x1560 net/core/rtnetlink.c:4598 netlink_rcv_skb+0x355/0x5f0 net/netlink/af_netlink.c:2447 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4653 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline] netlink_unicast+0x1672/0x1750 net/netlink/af_netlink.c:1337 netlink_sendmsg+0x1048/0x1310 net/netlink/af_netlink.c:1900 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046 __sys_sendmsg net/socket.c:2080 [inline] SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091 SyS_sendmsg+0x54/0x80 net/socket.c:2087 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x43fed9 RSP: 002b:00007ffddbee2798 EFLAGS: 00000213 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fed9 RDX: 0000000000000000 RSI: 0000000020005000 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8 R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000401800 R13: 0000000000401890 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline] kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321 slab_post_alloc_hook mm/slab.h:445 [inline] slab_alloc_node mm/slub.c:2737 [inline] __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369 __kmalloc_reserve net/core/skbuff.c:138 [inline] __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206 alloc_skb include/linux/skbuff.h:984 [inline] netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline] netlink_sendmsg+0x9a6/0x1310 net/netlink/af_netlink.c:1875 sock_sendmsg_nosec net/socket.c:630 [inline] sock_sendmsg net/socket.c:640 [inline] ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046 __sys_sendmsg net/socket.c:2080 [inline] SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091 SyS_sendmsg+0x54/0x80 net/socket.c:2087 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 Fixes: 21fdd092acc7 ("net: Add support for filtering neigh dump by master device") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: David Ahern <dsa@cumulusnetworks.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: David Ahern <dsa@cumulusnetworks.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 7dd07c143a4b54d050e748bee4b4b9e94a7b1744 ]

Since neigh_dump_table() calls nlmsg_parse() without giving policy
constraints, attributes can have arbirary size that we must validate

Reported by syzbot/KMSAN :

BUG: KMSAN: uninit-value in neigh_master_filtered net/core/neighbour.c:2292 [inline]
BUG: KMSAN: uninit-value in neigh_dump_table net/core/neighbour.c:2348 [inline]
BUG: KMSAN: uninit-value in neigh_dump_info+0x1af0/0x2250 net/core/neighbour.c:2438
CPU: 1 PID: 3575 Comm: syzkaller268891 Not tainted 4.16.0+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x185/0x1d0 lib/dump_stack.c:53
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:676
 neigh_master_filtered net/core/neighbour.c:2292 [inline]
 neigh_dump_table net/core/neighbour.c:2348 [inline]
 neigh_dump_info+0x1af0/0x2250 net/core/neighbour.c:2438
 netlink_dump+0x9ad/0x1540 net/netlink/af_netlink.c:2225
 __netlink_dump_start+0x1167/0x12a0 net/netlink/af_netlink.c:2322
 netlink_dump_start include/linux/netlink.h:214 [inline]
 rtnetlink_rcv_msg+0x1435/0x1560 net/core/rtnetlink.c:4598
 netlink_rcv_skb+0x355/0x5f0 net/netlink/af_netlink.c:2447
 rtnetlink_rcv+0x50/0x60 net/core/rtnetlink.c:4653
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x1672/0x1750 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0x1048/0x1310 net/netlink/af_netlink.c:1900
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2
RIP: 0033:0x43fed9
RSP: 002b:00007ffddbee2798 EFLAGS: 00000213 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fed9
RDX: 0000000000000000 RSI: 0000000020005000 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000213 R12: 0000000000401800
R13: 0000000000401890 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:278 [inline]
 kmsan_internal_poison_shadow+0xb8/0x1b0 mm/kmsan/kmsan.c:188
 kmsan_kmalloc+0x94/0x100 mm/kmsan/kmsan.c:314
 kmsan_slab_alloc+0x11/0x20 mm/kmsan/kmsan.c:321
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc_node mm/slub.c:2737 [inline]
 __kmalloc_node_track_caller+0xaed/0x11c0 mm/slub.c:4369
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cf/0x9f0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:984 [inline]
 netlink_alloc_large_skb net/netlink/af_netlink.c:1183 [inline]
 netlink_sendmsg+0x9a6/0x1310 net/netlink/af_netlink.c:1875
 sock_sendmsg_nosec net/socket.c:630 [inline]
 sock_sendmsg net/socket.c:640 [inline]
 ___sys_sendmsg+0xec0/0x1310 net/socket.c:2046
 __sys_sendmsg net/socket.c:2080 [inline]
 SYSC_sendmsg+0x2a3/0x3d0 net/socket.c:2091
 SyS_sendmsg+0x54/0x80 net/socket.c:2087
 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x3d/0xa2

Fixes: 21fdd092acc7 ("net: Add support for filtering neigh dump by master device")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: David Ahern <dsa@cumulusnetworks.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
llc: fix NULL pointer deref for SOCK_ZAPPED 2018-04-29T09:35:48+00:00 Cong Wang xiyou.wangcong@gmail.com 2018-04-20T04:54:34+00:00 793f3b16d2031e9affc0f33fb08241f4a448f814 [ Upstream commit 3a04ce7130a7e5dad4e78d45d50313747f8c830f ] For SOCK_ZAPPED socket, we don't need to care about llc->sap, so we should just skip these refcount functions in this case. Fixes: f7e43672683b ("llc: hold llc_sap before release_sock()") Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 3a04ce7130a7e5dad4e78d45d50313747f8c830f ]

For SOCK_ZAPPED socket, we don't need to care about llc->sap,
so we should just skip these refcount functions in this case.

Fixes: f7e43672683b ("llc: hold llc_sap before release_sock()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
llc: hold llc_sap before release_sock() 2018-04-29T09:35:48+00:00 Cong Wang xiyou.wangcong@gmail.com 2018-04-18T18:51:56+00:00 1f18e0884a6f721a0b9f02c8033acf1bd0c7f646 [ Upstream commit f7e43672683b097bb074a8fe7af9bc600a23f231 ] syzbot reported we still access llc->sap in llc_backlog_rcv() after it is freed in llc_sap_remove_socket(): Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1b9/0x294 lib/dump_stack.c:113 print_address_description+0x6c/0x20b mm/kasan/report.c:256 kasan_report_error mm/kasan/report.c:354 [inline] kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430 llc_conn_ac_send_sabme_cmd_p_set_x+0x3a8/0x460 net/llc/llc_c_ac.c:785 llc_exec_conn_trans_actions net/llc/llc_conn.c:475 [inline] llc_conn_service net/llc/llc_conn.c:400 [inline] llc_conn_state_process+0x4e1/0x13a0 net/llc/llc_conn.c:75 llc_backlog_rcv+0x195/0x1e0 net/llc/llc_conn.c:891 sk_backlog_rcv include/net/sock.h:909 [inline] __release_sock+0x12f/0x3a0 net/core/sock.c:2335 release_sock+0xa4/0x2b0 net/core/sock.c:2850 llc_ui_release+0xc8/0x220 net/llc/af_llc.c:204 llc->sap is refcount'ed and llc_sap_remove_socket() is paired with llc_sap_add_socket(). This can be amended by holding its refcount before llc_sap_remove_socket() and releasing it after release_sock(). Reported-by: <syzbot+6e181fc95081c2cf9051@syzkaller.appspotmail.com> Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit f7e43672683b097bb074a8fe7af9bc600a23f231 ]

syzbot reported we still access llc->sap in llc_backlog_rcv()
after it is freed in llc_sap_remove_socket():

Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report.c:430
 llc_conn_ac_send_sabme_cmd_p_set_x+0x3a8/0x460 net/llc/llc_c_ac.c:785
 llc_exec_conn_trans_actions net/llc/llc_conn.c:475 [inline]
 llc_conn_service net/llc/llc_conn.c:400 [inline]
 llc_conn_state_process+0x4e1/0x13a0 net/llc/llc_conn.c:75
 llc_backlog_rcv+0x195/0x1e0 net/llc/llc_conn.c:891
 sk_backlog_rcv include/net/sock.h:909 [inline]
 __release_sock+0x12f/0x3a0 net/core/sock.c:2335
 release_sock+0xa4/0x2b0 net/core/sock.c:2850
 llc_ui_release+0xc8/0x220 net/llc/af_llc.c:204

llc->sap is refcount'ed and llc_sap_remove_socket() is paired
with llc_sap_add_socket(). This can be amended by holding its refcount
before llc_sap_remove_socket() and releasing it after release_sock().

Reported-by: <syzbot+6e181fc95081c2cf9051@syzkaller.appspotmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
l2tp: fix {pppol2tp, l2tp_dfs}_seq_stop() in case of seq_file overflow 2018-04-29T09:35:48+00:00 Guillaume Nault g.nault@alphalink.fr 2018-04-19T14:20:48+00:00 ff373ad92b082fafb119f0ca7c2f17c1f48961b5 [ Upstream commit 5411b6187adf62909e3b998ac782e722904c7487 ] Commit 0e0c3fee3a59 ("l2tp: hold reference on tunnels printed in pppol2tp proc file") assumed that if pppol2tp_seq_stop() was called with non-NULL private data (the 'v' pointer), then pppol2tp_seq_start() would not be called again. It turns out that this isn't guaranteed, and overflowing the seq_file's buffer in pppol2tp_seq_show() is a way to get into this situation. Therefore, pppol2tp_seq_stop() needs to reset pd->tunnel, so that pppol2tp_seq_start() won't drop a reference again if it gets called. We also have to clear pd->session, because the rest of the code expects a non-NULL tunnel when pd->session is set. The l2tp_debugfs module has the same issue. Fix it in the same way. Fixes: 0e0c3fee3a59 ("l2tp: hold reference on tunnels printed in pppol2tp proc file") Fixes: f726214d9b23 ("l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 5411b6187adf62909e3b998ac782e722904c7487 ]

Commit 0e0c3fee3a59 ("l2tp: hold reference on tunnels printed in pppol2tp proc file")
assumed that if pppol2tp_seq_stop() was called with non-NULL private
data (the 'v' pointer), then pppol2tp_seq_start() would not be called
again. It turns out that this isn't guaranteed, and overflowing the
seq_file's buffer in pppol2tp_seq_show() is a way to get into this
situation.

Therefore, pppol2tp_seq_stop() needs to reset pd->tunnel, so that
pppol2tp_seq_start() won't drop a reference again if it gets called.
We also have to clear pd->session, because the rest of the code expects
a non-NULL tunnel when pd->session is set.

The l2tp_debugfs module has the same issue. Fix it in the same way.

Fixes: 0e0c3fee3a59 ("l2tp: hold reference on tunnels printed in pppol2tp proc file")
Fixes: f726214d9b23 ("l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file 2018-04-29T09:35:48+00:00 Guillaume Nault g.nault@alphalink.fr 2018-04-12T18:50:35+00:00 9a8863e8a8def9d88583cd9c60db38a008e6b8cf [ Upstream commit f726214d9b23e5fce8c11937577a289a3202498f ] Use l2tp_tunnel_get_nth() instead of l2tp_tunnel_find_nth(), to be safe against concurrent tunnel deletion. Use the same mechanism as in l2tp_ppp.c for dropping the reference taken by l2tp_tunnel_get_nth(). That is, drop the reference just before looking up the next tunnel. In case of error, drop the last accessed tunnel in l2tp_dfs_seq_stop(). That was the last use of l2tp_tunnel_find_nth(). Fixes: 0ad6614048cf ("l2tp: Add debugfs files for dumping l2tp debug info") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit f726214d9b23e5fce8c11937577a289a3202498f ]

Use l2tp_tunnel_get_nth() instead of l2tp_tunnel_find_nth(), to be safe
against concurrent tunnel deletion.

Use the same mechanism as in l2tp_ppp.c for dropping the reference
taken by l2tp_tunnel_get_nth(). That is, drop the reference just
before looking up the next tunnel. In case of error, drop the last
accessed tunnel in l2tp_dfs_seq_stop().

That was the last use of l2tp_tunnel_find_nth().

Fixes: 0ad6614048cf ("l2tp: Add debugfs files for dumping l2tp debug info")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
l2tp: hold reference on tunnels printed in pppol2tp proc file 2018-04-29T09:35:48+00:00 Guillaume Nault g.nault@alphalink.fr 2018-04-12T18:50:34+00:00 7f8e401f9e612df2a95c1ef76217c00181389bb5 [ Upstream commit 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ] Use l2tp_tunnel_get_nth() instead of l2tp_tunnel_find_nth(), to be safe against concurrent tunnel deletion. Unlike sessions, we can't drop the reference held on tunnels in pppol2tp_seq_show(). Tunnels are reused across several calls to pppol2tp_seq_start() when iterating over sessions. These iterations need the tunnel for accessing the next session. Therefore the only safe moment for dropping the reference is just before searching for the next tunnel. Normally, the last invocation of pppol2tp_next_tunnel() doesn't find any new tunnel, so it drops the last tunnel without taking any new reference. However, in case of error, pppol2tp_seq_stop() is called directly, so we have to drop the reference there. Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts") Signed-off-by: Guillaume Nault <g.nault@alphalink.fr> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
[ Upstream commit 0e0c3fee3a59a387aeecc4fca6f3a2e9615a5443 ]

Use l2tp_tunnel_get_nth() instead of l2tp_tunnel_find_nth(), to be safe
against concurrent tunnel deletion.

Unlike sessions, we can't drop the reference held on tunnels in
pppol2tp_seq_show(). Tunnels are reused across several calls to
pppol2tp_seq_start() when iterating over sessions. These iterations
need the tunnel for accessing the next session. Therefore the only safe
moment for dropping the reference is just before searching for the next
tunnel.

Normally, the last invocation of pppol2tp_next_tunnel() doesn't find
any new tunnel, so it drops the last tunnel without taking any new
reference. However, in case of error, pppol2tp_seq_stop() is called
directly, so we have to drop the reference there.

Fixes: fd558d186df2 ("l2tp: Split pppol2tp patch into separate l2tp and ppp parts")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>