audit: type=1400 audit(1581961807.481:36): avc: denied { map } for pid=7261 comm="syz-executor607" path="/root/syz-executor607211838" dev="sda1" ino=16483 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
==================================================================
BUG: KASAN: use-after-free in con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:2930
Write of size 8 at addr ffff8880a48ff808 by task syz-executor607/7269
CPU: 1 PID: 7269 Comm: syz-executor607 Not tainted 4.14.171-syzkaller #0
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+0x142/0x197 lib/dump_stack.c:58
print_address_description.cold+0x7c/0x1dc mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report mm/kasan/report.c:409 [inline]
kasan_report.cold+0xa9/0x2af mm/kasan/report.c:393
__asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435
con_shutdown+0x85/0x90 drivers/tty/vt/vt.c:2930
release_tty+0xbf/0x7c0 drivers/tty/tty_io.c:1501
tty_release_struct+0x3c/0x50 drivers/tty/tty_io.c:1616
tty_release+0xaa3/0xd60 drivers/tty/tty_io.c:1776
__fput+0x275/0x7a0 fs/file_table.c:210
____fput+0x16/0x20 fs/file_table.c:244
task_work_run+0x114/0x190 kernel/task_work.c:113
exit_task_work include/linux/task_work.h:22 [inline]
do_exit+0xa1a/0x2cd0 kernel/exit.c:858
do_group_exit+0x111/0x330 kernel/exit.c:955
SYSC_exit_group kernel/exit.c:966 [inline]
SyS_exit_group+0x1d/0x20 kernel/exit.c:964
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x43ff38
RSP: 002b:00007ffdf939d488 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000000000043ff38
RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000
RBP: 00000000004bf950 R08: 00000000000000e7 R09: ffffffffffffffd0
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000006d2180 R14: 0000000000000000 R15: 0000000000000000
Allocated by task 7269:
save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
save_stack+0x45/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc mm/kasan/kasan.c:551 [inline]
kasan_kmalloc+0xce/0xf0 mm/kasan/kasan.c:529
kmem_cache_alloc_trace+0x152/0x790 mm/slab.c:3618
kmalloc include/linux/slab.h:488 [inline]
kzalloc include/linux/slab.h:661 [inline]
vc_allocate drivers/tty/vt/vt.c:772 [inline]
vc_allocate+0x148/0x580 drivers/tty/vt/vt.c:753
con_install+0x52/0x400 drivers/tty/vt/vt.c:2881
tty_driver_install_tty drivers/tty/tty_io.c:1225 [inline]
tty_init_dev drivers/tty/tty_io.c:1338 [inline]
tty_init_dev+0xea/0x3a0 drivers/tty/tty_io.c:1315
tty_open_by_driver drivers/tty/tty_io.c:1973 [inline]
tty_open+0x414/0xa10 drivers/tty/tty_io.c:2021
chrdev_open+0x207/0x590 fs/char_dev.c:423
do_dentry_open+0x73b/0xeb0 fs/open.c:777
vfs_open+0x105/0x220 fs/open.c:891
do_last fs/namei.c:3428 [inline]
path_openat+0x917/0x3e50 fs/namei.c:3569
do_filp_open+0x18e/0x250 fs/namei.c:3603
do_sys_open+0x2c5/0x430 fs/open.c:1084
SYSC_open fs/open.c:1102 [inline]
SyS_open+0x2d/0x40 fs/open.c:1097
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
Freed by task 7274:
save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
save_stack+0x45/0xd0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
__cache_free mm/slab.c:3496 [inline]
kfree+0xcc/0x270 mm/slab.c:3815
vt_disallocate_all+0x286/0x380 drivers/tty/vt/vt_ioctl.c:323
vt_ioctl+0x76b/0x2170 drivers/tty/vt/vt_ioctl.c:816
tty_ioctl+0x841/0x1320 drivers/tty/tty_io.c:2661
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:500 [inline]
do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684
SYSC_ioctl fs/ioctl.c:701 [inline]
SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
The buggy address belongs to the object at ffff8880a48ff700
which belongs to the cache kmalloc-2048 of size 2048
The buggy address is located 264 bytes inside of
2048-byte region [ffff8880a48ff700, ffff8880a48fff00)
The buggy address belongs to the page:
page:ffffea0002923f80 count:1 mapcount:0 mapping:ffff8880a48fe600 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff8880a48fe600 0000000000000000 0000000100000003
raw: ffffea000209b0a0 ffffea0002933c20 ffff8880aa800c40 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff8880a48ff700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a48ff780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880a48ff800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880a48ff880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a48ff900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================