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KASAN: slab-out-of-bounds Read in xfrm_policy_inexact_insert

Status: fixed on 2019/03/06 07:43
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+ededf2bd5d663a945d57@syzkaller.appspotmail.com
Fix commit: 12750abad517 xfrm: policy: fix infinite loop when merging src-nodes
First crash: 2003d, last: 1979d
Discussions (1)
Title Replies (including bot) Last reply
KASAN: slab-out-of-bounds Read in xfrm_policy_inexact_insert 0 (1) 2018/12/20 12:11

Sample crash report:
IPv6 header not found
IPv6 header not found
==================================================================
BUG: KASAN: slab-out-of-bounds in xfrm_policy_insert_inexact_list net/xfrm/xfrm_policy.c:1496 [inline]
BUG: KASAN: slab-out-of-bounds in xfrm_policy_inexact_insert+0xc11/0xda0 net/xfrm/xfrm_policy.c:1202
Read of size 8 at addr ffff888093dce868 by task syz-executor4/4193

CPU: 1 PID: 4193 Comm: syz-executor4 Not tainted 4.20.0+ #18
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+0x1db/0x2d0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
 kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 xfrm_policy_insert_inexact_list net/xfrm/xfrm_policy.c:1496 [inline]
 xfrm_policy_inexact_insert+0xc11/0xda0 net/xfrm/xfrm_policy.c:1202
 xfrm_policy_insert+0x623/0x910 net/xfrm/xfrm_policy.c:1570
 xfrm_add_policy+0x2a1/0x6c0 net/xfrm/xfrm_user.c:1657
 xfrm_user_rcv_msg+0x458/0x8d0 net/xfrm/xfrm_user.c:2663
 netlink_rcv_skb+0x17d/0x410 net/netlink/af_netlink.c:2477
 xfrm_netlink_rcv+0x70/0x90 net/xfrm/xfrm_user.c:2671
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x574/0x770 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 ___sys_sendmsg+0x7ec/0x910 net/socket.c:2116
 __sys_sendmsg+0x112/0x270 net/socket.c:2154
 __do_sys_sendmsg net/socket.c:2163 [inline]
 __se_sys_sendmsg net/socket.c:2161 [inline]
 __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457ec9
Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2c058ebc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9
RDX: 0000000000008000 RSI: 0000000020000480 RDI: 0000000000000007
RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2c058ec6d4
R13: 00000000004c5394 R14: 00000000004d8e30 R15: 00000000ffffffff

Allocated by task 30456:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 kasan_kmalloc mm/kasan/common.c:482 [inline]
 kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455
 __do_kmalloc mm/slab.c:3709 [inline]
 __kmalloc+0x15c/0x740 mm/slab.c:3718
 kmalloc_array include/linux/slab.h:668 [inline]
 kcalloc include/linux/slab.h:679 [inline]
 veth_alloc_queues drivers/net/veth.c:923 [inline]
 veth_dev_init+0x11c/0x2f0 drivers/net/veth.c:950
 register_netdevice+0x30d/0x10b0 net/core/dev.c:8559
 veth_newlink+0x58d/0xa60 drivers/net/veth.c:1298
 __rtnl_newlink+0x1281/0x1a70 net/core/rtnetlink.c:3182
 rtnl_newlink+0x69/0xa0 net/core/rtnetlink.c:3240
 rtnetlink_rcv_msg+0x481/0xc30 net/core/rtnetlink.c:5130
 netlink_rcv_skb+0x17d/0x410 net/netlink/af_netlink.c:2477
 rtnetlink_rcv+0x1d/0x30 net/core/rtnetlink.c:5148
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x574/0x770 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0xa05/0xf90 net/netlink/af_netlink.c:1917
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg+0xdd/0x130 net/socket.c:631
 __sys_sendto+0x387/0x5f0 net/socket.c:1788
 __do_sys_sendto net/socket.c:1800 [inline]
 __se_sys_sendto net/socket.c:1796 [inline]
 __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1796
 do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 28506:
 save_stack+0x45/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452
 __cache_free mm/slab.c:3485 [inline]
 kfree+0xcf/0x230 mm/slab.c:3804
 in6_dev_finish_destroy_rcu+0x8a/0xb0 net/ipv6/addrconf_core.c:209
 __rcu_reclaim kernel/rcu/rcu.h:240 [inline]
 rcu_do_batch kernel/rcu/tree.c:2452 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2773 [inline]
 rcu_process_callbacks+0xc4a/0x1680 kernel/rcu/tree.c:2754
 __do_softirq+0x30b/0xb11 kernel/softirq.c:292

The buggy address belongs to the object at ffff888093dce4c0
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 936 bytes inside of
 1024-byte region [ffff888093dce4c0, ffff888093dce8c0)
The buggy address belongs to the page:
page:ffffea00024f7380 count:1 mapcount:0 mapping:ffff88812c3f0ac0 index:0x0 compound_mapcount: 0
flags: 0x1fffc0000010200(slab|head)
raw: 01fffc0000010200 ffffea0002528288 ffffea00018b4f08 ffff88812c3f0ac0
raw: 0000000000000000 ffff888093dce040 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888093dce700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888093dce780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888093dce800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                                                          ^
 ffff888093dce880: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888093dce900: fc fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00
==================================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/01/13 03:20 net-old 8d008e64a2eb c3f3344c .config console log report ci-upstream-net-this-kasan-gce
2019/01/11 18:18 net-next-old b71acb0e3721 c3f3344c .config console log report ci-upstream-net-kasan-gce
2018/12/19 20:19 net-next-old 33f18c96afdf fe2dc057 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.