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Alexander Sverdlin 59a460c394 sctp: Fix race between OOTB responce and route removal 
[ Upstream commit 29c4afc4e9 ]

There is NULL pointer dereference possible during statistics update if the route
used for OOTB responce is removed at unfortunate time. If the route exists when
we receive OOTB packet and we finally jump into sctp_packet_transmit() to send
ABORT, but in the meantime route is removed under our feet, we take "no_route"
path and try to update stats with IP_INC_STATS(sock_net(asoc->base.sk), ...).

But sctp_ootb_pkt_new() used to prepare responce packet doesn't call
sctp_transport_set_owner() and therefore there is no asoc associated with this
packet. Probably temporary asoc just for OOTB responces is overkill, so just
introduce a check like in all other places in sctp_packet_transmit(), where
"asoc" is dereferenced.

To reproduce this, one needs to
0. ensure that sctp module is loaded (otherwise ABORT is not generated)
1. remove default route on the machine
2. while true; do
     ip route del [interface-specific route]
     ip route add [interface-specific route]
   done
3. send enough OOTB packets (i.e. HB REQs) from another host to trigger ABORT
   responce

On x86_64 the crash looks like this:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
IP: [<ffffffffa05ec9ac>] sctp_packet_transmit+0x63c/0x730 [sctp]
PGD 0
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: ...
CPU: 0 PID: 0 Comm: swapper/0 Tainted: G           O    4.0.5-1-ARCH #1
Hardware name: ...
task: ffffffff818124c0 ti: ffffffff81800000 task.ti: ffffffff81800000
RIP: 0010:[<ffffffffa05ec9ac>]  [<ffffffffa05ec9ac>] sctp_packet_transmit+0x63c/0x730 [sctp]
RSP: 0018:ffff880127c037b8  EFLAGS: 00010296
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000015ff66b480
RDX: 00000015ff66b400 RSI: ffff880127c17200 RDI: ffff880123403700
RBP: ffff880127c03888 R08: 0000000000017200 R09: ffffffff814625af
R10: ffffea00047e4680 R11: 00000000ffffff80 R12: ffff8800b0d38a28
R13: ffff8800b0d38a28 R14: ffff8800b3e88000 R15: ffffffffa05f24e0
FS:  0000000000000000(0000) GS:ffff880127c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000020 CR3: 00000000c855b000 CR4: 00000000000007f0
Stack:
 ffff880127c03910 ffff8800b0d38a28 ffffffff8189d240 ffff88011f91b400
 ffff880127c03828 ffffffffa05c94c5 0000000000000000 ffff8800baa1c520
 0000000000000000 0000000000000001 0000000000000000 0000000000000000
Call Trace:
 <IRQ>
 [<ffffffffa05c94c5>] ? sctp_sf_tabort_8_4_8.isra.20+0x85/0x140 [sctp]
 [<ffffffffa05d6b42>] ? sctp_transport_put+0x52/0x80 [sctp]
 [<ffffffffa05d0bfc>] sctp_do_sm+0xb8c/0x19a0 [sctp]
 [<ffffffff810b0e00>] ? trigger_load_balance+0x90/0x210
 [<ffffffff810e0329>] ? update_process_times+0x59/0x60
 [<ffffffff812c7a40>] ? timerqueue_add+0x60/0xb0
 [<ffffffff810e0549>] ? enqueue_hrtimer+0x29/0xa0
 [<ffffffff8101f599>] ? read_tsc+0x9/0x10
 [<ffffffff8116d4b5>] ? put_page+0x55/0x60
 [<ffffffff810ee1ad>] ? clockevents_program_event+0x6d/0x100
 [<ffffffff81462b68>] ? skb_free_head+0x58/0x80
 [<ffffffffa029a10b>] ? chksum_update+0x1b/0x27 [crc32c_generic]
 [<ffffffff81283f3e>] ? crypto_shash_update+0xce/0xf0
 [<ffffffffa05d3993>] sctp_endpoint_bh_rcv+0x113/0x280 [sctp]
 [<ffffffffa05dd4e6>] sctp_inq_push+0x46/0x60 [sctp]
 [<ffffffffa05ed7a0>] sctp_rcv+0x880/0x910 [sctp]
 [<ffffffffa05ecb50>] ? sctp_packet_transmit_chunk+0xb0/0xb0 [sctp]
 [<ffffffffa05ecb70>] ? sctp_csum_update+0x20/0x20 [sctp]
 [<ffffffff814b05a5>] ? ip_route_input_noref+0x235/0xd30
 [<ffffffff81051d6b>] ? ack_ioapic_level+0x7b/0x150
 [<ffffffff814b27be>] ip_local_deliver_finish+0xae/0x210
 [<ffffffff814b2e15>] ip_local_deliver+0x35/0x90
 [<ffffffff814b2a15>] ip_rcv_finish+0xf5/0x370
 [<ffffffff814b3128>] ip_rcv+0x2b8/0x3a0
 [<ffffffff81474193>] __netif_receive_skb_core+0x763/0xa50
 [<ffffffff81476c28>] __netif_receive_skb+0x18/0x60
 [<ffffffff81476cb0>] netif_receive_skb_internal+0x40/0xd0
 [<ffffffff814776c8>] napi_gro_receive+0xe8/0x120
 [<ffffffffa03946aa>] rtl8169_poll+0x2da/0x660 [r8169]
 [<ffffffff8147896a>] net_rx_action+0x21a/0x360
 [<ffffffff81078dc1>] __do_softirq+0xe1/0x2d0
 [<ffffffff8107912d>] irq_exit+0xad/0xb0
 [<ffffffff8157d158>] do_IRQ+0x58/0xf0
 [<ffffffff8157b06d>] common_interrupt+0x6d/0x6d
 <EOI>
 [<ffffffff810e1218>] ? hrtimer_start+0x18/0x20
 [<ffffffffa05d65f9>] ? sctp_transport_destroy_rcu+0x29/0x30 [sctp]
 [<ffffffff81020c50>] ? mwait_idle+0x60/0xa0
 [<ffffffff810216ef>] arch_cpu_idle+0xf/0x20
 [<ffffffff810b731c>] cpu_startup_entry+0x3ec/0x480
 [<ffffffff8156b365>] rest_init+0x85/0x90
 [<ffffffff818eb035>] start_kernel+0x48b/0x4ac
 [<ffffffff818ea120>] ? early_idt_handlers+0x120/0x120
 [<ffffffff818ea339>] x86_64_start_reservations+0x2a/0x2c
 [<ffffffff818ea49c>] x86_64_start_kernel+0x161/0x184
Code: 90 48 8b 80 b8 00 00 00 48 89 85 70 ff ff ff 48 83 bd 70 ff ff ff 00 0f 85 cd fa ff ff 48 89 df 31 db e8 18 63 e7 e0 48 8b 45 80 <48> 8b 40 20 48 8b 40 30 48 8b 80 68 01 00 00 65 48 ff 40 78 e9
RIP  [<ffffffffa05ec9ac>] sctp_packet_transmit+0x63c/0x730 [sctp]
 RSP <ffff880127c037b8>
CR2: 0000000000000020
---[ end trace 5aec7fd2dc983574 ]---
Kernel panic - not syncing: Fatal exception in interrupt
Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffff9fffffff)
drm_kms_helper: panic occurred, switching back to text console
---[ end Kernel panic - not syncing: Fatal exception in interrupt

Signed-off-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-10 10:40:21 -07:00
..
associola.c net: sctp: fix slab corruption from use after free on INIT collisions 2015-02-26 17:48:48 -08:00
auth.c net: sctp: fix memory leak in auth key management 2014-11-21 09:22:51 -08:00
bind_addr.c net: sctp: sctp_bind_addr: remove dead code 2013-04-17 14:13:02 -04:00
chunk.c sctp: fix -ENOMEM result with invalid user space pointer in sendto() syscall 2012-11-28 11:11:17 -05:00
command.c
debug.c sctp: remove completely unsed EMPTY state 2011-04-20 01:51:03 -07:00
endpointola.c net: sctp: cache auth_enable per endpoint 2014-05-30 21:52:15 -07:00
input.c net: sctp: rfc4443: do not report ICMP redirects to user space 2013-10-13 16:08:29 -07:00
inqueue.c net: sctp: fix remote memory pressure from excessive queueing 2014-11-21 09:22:55 -08:00
ipv6.c net: sctp: rfc4443: do not report ICMP redirects to user space 2013-10-13 16:08:29 -07:00
Kconfig net, sctp: remove CONFIG_EXPERIMENTAL 2013-02-13 13:57:27 -05:00
Makefile sctp: implement sctp association probing module 2010-04-30 22:41:09 -04:00
objcnt.c sctp: Make the proc files per network namespace. 2012-08-14 23:29:53 -07:00
output.c sctp: Fix race between OOTB responce and route removal 2015-07-10 10:40:21 -07:00
outqueue.c sctp: fully initialize sctp_outq in sctp_outq_init 2013-06-13 18:05:24 -07:00
primitive.c sctp: Push struct net down to sctp_chunk_event_lookup 2012-08-14 23:30:37 -07:00
probe.c net: sctp: attribute printl with __printf for gcc fmt checks 2013-05-01 15:04:10 -04:00
proc.c sctp: Add buffer utilization fields to /proc/net/sctp/assocs 2013-04-16 16:43:34 -04:00
protocol.c sctp: reset flowi4_oif parameter on route lookup 2014-05-30 21:52:16 -07:00
sm_make_chunk.c net: sctp: fix passing wrong parameter header to param_type2af in sctp_process_param 2015-02-26 17:48:49 -08:00
sm_sideeffect.c net: remove redundant check for timer pending state before del_timer 2013-02-04 13:26:49 -05:00
sm_statefuns.c net: sctp: fix skb_over_panic when receiving malformed ASCONF chunks 2014-11-21 09:22:55 -08:00
sm_statetable.c sctp: Make sysctl tunables per net 2012-08-14 23:32:16 -07:00
socket.c net: sctp: cache auth_enable per endpoint 2014-05-30 21:52:15 -07:00
ssnmap.c net: sctp: sctp_ssnmap: remove 'malloced' element from struct 2013-04-17 14:13:02 -04:00
sysctl.c net: sctp: check proc_dointvec result in proc_sctp_do_auth 2014-07-28 08:00:04 -07:00
transport.c net: sctp: sctp_transport: remove unused variable 2013-04-17 14:13:02 -04:00
tsnmap.c sctp: fix association hangs due to off-by-one errors in sctp_tsnmap_grow() 2013-02-28 15:34:26 -05:00
ulpevent.c net: sctp: fix information leaks in ulpevent layer 2014-07-28 08:00:05 -07:00
ulpqueue.c net: sctp: sctp_ulpq: remove 'malloced' struct member 2013-04-17 14:13:02 -04:00