syzbot


KASAN: use-after-free Read in sctp_do_sm

Status: fixed on 2018/05/17 10:02
Subsystems: sctp
[Documentation on labels]
Reported-by: syzbot+141d898c5f24489db4aa@syzkaller.appspotmail.com
Fix commit: 6910e25de225 sctp: remove sctp_chunk_put from fail_mark err path in sctp_ulpevent_make_rcvmsg
First crash: 2230d, last: 2229d
Discussions (5)
Title Replies (including bot) Last reply
[PATCH 4.16 00/55] 4.16.10-stable review 63 (63) 2018/05/19 07:43
[PATCH 4.9 00/33] 4.9.101-stable review 40 (40) 2018/05/18 20:47
[PATCH 4.14 00/45] 4.14.42-stable review 50 (50) 2018/05/18 20:46
[PATCH net] sctp: remove sctp_chunk_put from fail_mark err path in sctp_ulpevent_make_rcvmsg 4 (4) 2018/05/10 21:49
KASAN: use-after-free Read in sctp_do_sm 2 (3) 2018/05/08 18:57

Sample crash report:
RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000016
R13: 000000000000071f R14: 00000000006feb88 R15: 0000000000000007
==================================================================
BUG: KASAN: use-after-free in sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1817 [inline]
BUG: KASAN: use-after-free in sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
BUG: KASAN: use-after-free in sctp_do_sm+0x6015/0x7160 net/sctp/sm_sideeffect.c:1191
Read of size 1 at addr ffff8801d86b8e38 by task syz-executor2/28473

CPU: 0 PID: 28473 Comm: syz-executor2 Not tainted 4.17.0-rc4+ #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1817 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
 sctp_do_sm+0x6015/0x7160 net/sctp/sm_sideeffect.c:1191
 sctp_assoc_bh_rcv+0x30f/0x520 net/sctp/associola.c:1065
 sctp_inq_push+0x263/0x320 net/sctp/inqueue.c:95
 sctp_backlog_rcv+0x192/0xc00 net/sctp/input.c:350
 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
 sctp_sendmsg+0x13cc/0x1d70 net/sctp/socket.c:2128
 inet_sendmsg+0x19f/0x690 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 sock_write_iter+0x35a/0x5a0 net/socket.c:908
 call_write_iter include/linux/fs.h:1784 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x64d/0x960 fs/read_write.c:487
 vfs_write+0x1f8/0x560 fs/read_write.c:549
 ksys_write+0xf9/0x250 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455979
RSP: 002b:00007f96c58b4c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f96c58b56d4 RCX: 0000000000455979
RDX: 0000000000000008 RSI: 0000000020000000 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000016
R13: 000000000000071f R14: 00000000006feb88 R15: 0000000000000007

Allocated by task 28473:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
 kmem_cache_zalloc include/linux/slab.h:691 [inline]
 sctp_chunkify+0xce/0x400 net/sctp/sm_make_chunk.c:1355
 sctp_rcv+0xc65/0x3a60 net/sctp/input.c:221
 sctp6_rcv+0x15/0x30 net/sctp/ipv6.c:1045
 ip6_input_finish+0x3ff/0x1a30 net/ipv6/ip6_input.c:284
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip6_input+0xe1/0x5e0 net/ipv6/ip6_input.c:327
 dst_input include/net/dst.h:450 [inline]
 ip6_rcv_finish+0x29c/0xa10 net/ipv6/ip6_input.c:71
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ipv6_rcv+0xed6/0x22a0 net/ipv6/ip6_input.c:208
 __netif_receive_skb_core+0x26f5/0x3630 net/core/dev.c:4592
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:4657
 process_backlog+0x219/0x760 net/core/dev.c:5337
 napi_poll net/core/dev.c:5735 [inline]
 net_rx_action+0x7b7/0x1930 net/core/dev.c:5801
 __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285

Freed by task 28473:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
 sctp_chunk_destroy net/sctp/sm_make_chunk.c:1481 [inline]
 sctp_chunk_put+0x321/0x440 net/sctp/sm_make_chunk.c:1504
 sctp_ulpevent_make_rcvmsg+0x955/0xd40 net/sctp/ulpevent.c:718
 sctp_ulpq_tail_data+0xa8/0x12b0 net/sctp/ulpqueue.c:108
 sctp_cmd_interpreter net/sctp/sm_sideeffect.c:1478 [inline]
 sctp_side_effects net/sctp/sm_sideeffect.c:1220 [inline]
 sctp_do_sm+0x1658/0x7160 net/sctp/sm_sideeffect.c:1191
 sctp_assoc_bh_rcv+0x30f/0x520 net/sctp/associola.c:1065
 sctp_inq_push+0x263/0x320 net/sctp/inqueue.c:95
 sctp_backlog_rcv+0x192/0xc00 net/sctp/input.c:350
 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
 sctp_sendmsg+0x13cc/0x1d70 net/sctp/socket.c:2128
 inet_sendmsg+0x19f/0x690 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 sock_write_iter+0x35a/0x5a0 net/socket.c:908
 call_write_iter include/linux/fs.h:1784 [inline]
 new_sync_write fs/read_write.c:474 [inline]
 __vfs_write+0x64d/0x960 fs/read_write.c:487
 vfs_write+0x1f8/0x560 fs/read_write.c:549
 ksys_write+0xf9/0x250 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801d86b8d40
 which belongs to the cache sctp_chunk of size 256
The buggy address is located 248 bytes inside of
 256-byte region [ffff8801d86b8d40, ffff8801d86b8e40)
The buggy address belongs to the page:
page:ffffea000761ae00 count:1 mapcount:0 mapping:ffff8801d86b80c0 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d86b80c0 0000000000000000 000000010000000c
raw: ffffea0007180f60 ffffea0006d2afa0 ffff8801cd494540 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d86b8d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801d86b8d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d86b8e00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                                        ^
 ffff8801d86b8e80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801d86b8f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/05/08 21:55 upstream 036db8bd9637 b88872ba .config console log report ci-upstream-kasan-gce
2018/05/08 06:24 upstream f142f08bf7ec 045bbd4a .config console log report ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.