syzbot


KASAN: use-after-free Write in __get_vm_area_node

Status: closed as invalid on 2018/05/26 17:47
Subsystems: netfilter
[Documentation on labels]
Reported-by: syzbot+c81b83fc8b16ad38fdb9@syzkaller.appspotmail.com
First crash: 2180d, last: 2180d

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in setup_vmalloc_vm mm/vmalloc.c:1366 [inline]
BUG: KASAN: use-after-free in __get_vm_area_node+0x373/0x390 mm/vmalloc.c:1415
Write of size 8 at addr ffff8801b2b1ea98 by task syz-executor3/4486

CPU: 1 PID: 4486 Comm: syz-executor3 Not tainted 4.16.0+ #1
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+0x1b9/0x29f lib/dump_stack.c:53
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0xac/0x2f5 mm/kasan/report.c:412
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:438
 setup_vmalloc_vm mm/vmalloc.c:1366 [inline]
 __get_vm_area_node+0x373/0x390 mm/vmalloc.c:1415
 __vmalloc_node_range+0xc4/0x720 mm/vmalloc.c:1754
 __vmalloc_node mm/vmalloc.c:1804 [inline]
 __vmalloc_node_flags mm/vmalloc.c:1818 [inline]
 vzalloc+0x45/0x50 mm/vmalloc.c:1857
 alloc_counters.isra.11+0xaf/0x830 net/ipv6/netfilter/ip6_tables.c:818
 copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:840 [inline]
 get_entries net/ipv6/netfilter/ip6_tables.c:1043 [inline]
 do_ip6t_get_ctl+0x7e3/0xc30 net/ipv6/netfilter/ip6_tables.c:1711
 nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
 nf_getsockopt+0x80/0xe0 net/netfilter/nf_sockopt.c:122
 ipv6_getsockopt+0x1d9/0x300 net/ipv6/ipv6_sockglue.c:1370
 tcp_getsockopt+0x93/0xe0 net/ipv4/tcp.c:3346
 sock_common_getsockopt+0x9a/0xe0 net/core/sock.c:2998
 __sys_getsockopt+0x1a5/0x370 net/socket.c:1940
 SYSC_getsockopt net/socket.c:1951 [inline]
 SyS_getsockopt+0x34/0x50 net/socket.c:1948
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x457d4a
RSP: 002b:0000000000a3e328 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000a3e350 RCX: 0000000000457d4a
RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000013
RBP: 00000000007010a0 R08: 0000000000a3e34c R09: 0000000000004000
R10: 0000000000a3e450 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000000013 R14: 0000000000000029 R15: 00000000007009e0

Allocated by task 1343:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:552
 kmem_cache_alloc_trace+0x152/0x780 mm/slab.c:3608
 kmalloc include/linux/slab.h:512 [inline]
 kzalloc include/linux/slab.h:701 [inline]
 ext4_htree_create_dir_info fs/ext4/dir.c:416 [inline]
 ext4_dx_readdir fs/ext4/dir.c:535 [inline]
 ext4_readdir+0x2722/0x3bb0 fs/ext4/dir.c:123
 iterate_dir+0x4b0/0x5d0 fs/readdir.c:51
 SYSC_getdents fs/readdir.c:231 [inline]
 SyS_getdents+0x22c/0x450 fs/readdir.c:212
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 1343:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3486 [inline]
 kfree+0xd9/0x260 mm/slab.c:3801
 ext4_htree_free_dir_info fs/ext4/dir.c:427 [inline]
 ext4_release_dir+0x4c/0x60 fs/ext4/dir.c:624
 __fput+0x34d/0x890 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1e4/0x290 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x2bd/0x310 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x792/0x9d0 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8801b2b1ea80
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 24 bytes inside of
 64-byte region [ffff8801b2b1ea80, ffff8801b2b1eac0)
The buggy address belongs to the page:
page:ffffea0006cac780 count:1 mapcount:0 mapping:ffff8801b2b1e000 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801b2b1e000 0000000000000000 0000000100000020
raw: ffffea00075b8260 ffffea0007162a20 ffff8801dac00340 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b2b1e980: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801b2b1ea00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8801b2b1ea80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                            ^
 ffff8801b2b1eb00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801b2b1eb80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/09 08:31 net-next-old 17dec0a94915 f13fb445 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.