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

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: ea7bbd69 UPSTREAM: serial: samsung: 32-bit access for TX/R..
git tree: android-5.4
console output: https://syzkaller.appspot.com/x/log.txt?x=12b9f99a100000
kernel config: https://syzkaller.appspot.com/x/.config?x=5993e04cebb65bd0
dashboard link: https://syzkaller.appspot.com/bug?extid=da7e980264b08b5379e4
compiler: Android (6032204 based on r370808) clang version 10.0.1 (https://android.googlesource.com/toolchain/llvm-project 6e765c10313d15c02ab29977a82938f66742c3a9)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+da7e98...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-out-of-bounds in __tipc_nl_add_nametable_publ net/tipc/name_table.c:815 [inline]
BUG: KASAN: slab-out-of-bounds in __tipc_nl_service_range_list net/tipc/name_table.c:885 [inline]
BUG: KASAN: slab-out-of-bounds in tipc_nl_service_list net/tipc/name_table.c:926 [inline]
BUG: KASAN: slab-out-of-bounds in tipc_nl_name_table_dump+0x1042/0x1620 net/tipc/name_table.c:960
Read of size 4 at addr ffff8881cf41baf8 by task syz-executor.3/1838

CPU: 0 PID: 1838 Comm: syz-executor.3 Tainted: G W 5.4.42-syzkaller-00393-gea7bbd69ade9 #0
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+0x14a/0x1ce lib/dump_stack.c:118
print_address_description+0x93/0x620 mm/kasan/report.c:374
__kasan_report+0x16d/0x1e0 mm/kasan/report.c:506
kasan_report+0x34/0x60 mm/kasan/common.c:634
__tipc_nl_add_nametable_publ net/tipc/name_table.c:815 [inline]
__tipc_nl_service_range_list net/tipc/name_table.c:885 [inline]
tipc_nl_service_list net/tipc/name_table.c:926 [inline]
tipc_nl_name_table_dump+0x1042/0x1620 net/tipc/name_table.c:960
__tipc_nl_compat_dumpit+0x25e/0x860 net/tipc/netlink_compat.c:207
tipc_nl_compat_dumpit+0x33e/0x4e0 net/tipc/netlink_compat.c:288
tipc_nl_compat_handle net/tipc/netlink_compat.c:1195 [inline]
tipc_nl_compat_recv+0x106c/0x2030 net/tipc/netlink_compat.c:1291
genl_family_rcv_msg net/netlink/genetlink.c:629 [inline]
genl_rcv_msg+0xeef/0x13c0 net/netlink/genetlink.c:654
netlink_rcv_skb+0x200/0x480 net/netlink/af_netlink.c:2478
genl_rcv+0x24/0x40 net/netlink/genetlink.c:665
netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
netlink_unicast+0x8ad/0xa50 net/netlink/af_netlink.c:1329
netlink_sendmsg+0x9de/0xd80 net/netlink/af_netlink.c:1918
sock_sendmsg_nosec net/socket.c:638 [inline]
sock_sendmsg net/socket.c:658 [inline]
kernel_sendmsg+0xe2/0x120 net/socket.c:678
sock_no_sendpage+0x145/0x1b0 net/core/sock.c:2745
kernel_sendpage net/socket.c:3764 [inline]
sock_sendpage+0xd0/0x120 net/socket.c:936
pipe_to_sendpage+0x23b/0x300 fs/splice.c:449
splice_from_pipe_feed fs/splice.c:500 [inline]
__splice_from_pipe+0x2d3/0x870 fs/splice.c:624
splice_from_pipe fs/splice.c:659 [inline]
generic_splice_sendpage+0x184/0x210 fs/splice.c:829
splice_direct_to_actor+0x496/0xb00 fs/splice.c:976
do_splice_direct+0x28b/0x3e0 fs/splice.c:1064
do_sendfile+0x8d6/0x1100 fs/read_write.c:1467
__do_sys_sendfile64 fs/read_write.c:1528 [inline]
__se_sys_sendfile64 fs/read_write.c:1514 [inline]
__x64_sys_sendfile64+0x1d4/0x230 fs/read_write.c:1514
do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ca29
Code: 0d 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f771fab4c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00000000004fc540 RCX: 000000000045ca29
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000008
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000100000001 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008dc R14: 00000000004cba16 R15: 00007f771fab56d4

Allocated by task 422:
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
__kasan_kmalloc+0x12c/0x1c0 mm/kasan/common.c:510
kmem_cache_alloc_trace+0xc3/0x280 mm/slub.c:2793
kmalloc include/linux/slab.h:556 [inline]
kzalloc include/linux/slab.h:690 [inline]
snmp6_alloc_dev net/ipv6/addrconf.c:346 [inline]
ipv6_add_dev+0x492/0x14a0 net/ipv6/addrconf.c:399
addrconf_notify+0x650/0x3790 net/ipv6/addrconf.c:3523
notifier_call_chain kernel/notifier.c:95 [inline]
__raw_notifier_call_chain kernel/notifier.c:396 [inline]
raw_notifier_call_chain+0x9e/0x100 kernel/notifier.c:403
call_netdevice_notifiers_info net/core/dev.c:1667 [inline]
call_netdevice_notifiers_extack net/core/dev.c:1679 [inline]
call_netdevice_notifiers net/core/dev.c:1693 [inline]
register_netdevice+0xeeb/0x1460 net/core/dev.c:9104
register_netdev+0x37/0x50 net/core/dev.c:9195
sit_init_net+0x225/0x480 net/ipv6/sit.c:1868
ops_init+0x26e/0x340 net/core/net_namespace.c:137
setup_net+0x22b/0xac0 net/core/net_namespace.c:335
copy_net_ns+0x2e5/0x4a0 net/core/net_namespace.c:476
create_new_namespaces+0x57b/0x680 kernel/nsproxy.c:103
unshare_nsproxy_namespaces+0x11e/0x180 kernel/nsproxy.c:202
ksys_unshare+0x52f/0xa40 kernel/fork.c:2874
__do_sys_unshare kernel/fork.c:2942 [inline]
__se_sys_unshare kernel/fork.c:2940 [inline]
__x64_sys_unshare+0x34/0x40 kernel/fork.c:2940
do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 374:
save_stack mm/kasan/common.c:69 [inline]
set_track mm/kasan/common.c:77 [inline]
kasan_set_free_info mm/kasan/common.c:332 [inline]
__kasan_slab_free+0x181/0x230 mm/kasan/common.c:471
slab_free_hook mm/slub.c:1424 [inline]
slab_free_freelist_hook+0xd0/0x150 mm/slub.c:1457
slab_free mm/slub.c:3014 [inline]
kfree+0x12b/0x600 mm/slub.c:3975
context_add_hash+0x1c7/0x280 security/selinux/ss/services.c:1478
context_struct_to_sid security/selinux/ss/services.c:1491 [inline]
security_get_user_sids+0x7c0/0x1310 security/selinux/ss/services.c:2657
sel_write_user+0x427/0x820 security/selinux/selinuxfs.c:1064
selinux_transaction_write+0xf2/0x130 security/selinux/selinuxfs.c:791
__vfs_write+0xfa/0x720 fs/read_write.c:496
vfs_write+0x217/0x4f0 fs/read_write.c:560
ksys_write+0x18c/0x2c0 fs/read_write.c:614
do_syscall_64+0xcb/0x150 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8881cf41ba80
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 56 bytes to the right of
64-byte region [ffff8881cf41ba80, ffff8881cf41bac0)
The buggy address belongs to the page:
page:ffffea00073d06c0 refcount:1 mapcount:0 mapping:ffff8881da803180 index:0x0
flags: 0x8000000000000200(slab)
raw: 8000000000000200 dead000000000100 dead000000000122 ffff8881da803180
raw: 0000000000000000 0000000000200020 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881cf41b980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff8881cf41ba00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
>ffff8881cf41ba80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
^
ffff8881cf41bb00: 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc fc
ffff8881cf41bb80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================


---
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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.