KASAN: use-after-free Read in ntfs

KASAN: use-after-free Read in ntfs_iget
Status: upstream: reported C repro on 2020/11/27 20:57
Reported-by: syzbot+c584225dabdea2f71969@syzkaller.appspotmail.com
First crash: 62d, last: 62d

Cause bisection: failed (bisect log)

Fix bisection: failed (bisect log)

similar bugs (2):
Kernel	Title	Repro	Cause bisect	Fix bisect	Count	Last	Reported	Patched	Status
linux-4.14	KASAN: use-after-free Read in ntfs_iget	C			2	18d	48d	0/1	upstream: reported C repro on 2020/12/07 09:40
linux-4.19	KASAN: use-after-free Read in ntfs_iget	C			1	29d	29d	0/1	upstream: reported C repro on 2020/12/26 21:54

Sample crash report:

==================================================================
BUG: KASAN: use-after-free in ntfs_read_locked_inode+0x49dc/0x58b0 fs/ntfs/inode.c:645
Read of size 8 at addr ffff8880374ee6cd by task syz-executor401/8528

CPU: 1 PID: 8528 Comm: syz-executor401 Not tainted 5.10.0-rc5-syzkaller #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+0x107/0x163 lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:385
 __kasan_report mm/kasan/report.c:545 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562
 ntfs_read_locked_inode+0x49dc/0x58b0 fs/ntfs/inode.c:645
 ntfs_iget+0x12d/0x180 fs/ntfs/inode.c:177
 load_and_init_attrdef fs/ntfs/super.c:1589 [inline]
 load_system_files fs/ntfs/super.c:1817 [inline]
 ntfs_fill_super+0x255c/0x8560 fs/ntfs/super.c:2893
 mount_bdev+0x32e/0x3f0 fs/super.c:1419
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1549
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x13ad/0x20c0 fs/namespace.c:3205
 do_mount fs/namespace.c:3218 [inline]
 __do_sys_mount fs/namespace.c:3426 [inline]
 __se_sys_mount fs/namespace.c:3403 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3403
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x44954a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 7d a3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 5a a3 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffe2910bd28 EFLAGS: 00000287 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe2910bd80 RCX: 000000000044954a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffe2910bd40
RBP: 00007ffe2910bd40 R08: 00007ffe2910bd80 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000287 R12: 00000000000000ac
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

The buggy address belongs to the page:
page:00000000dbe06e8c refcount:1 mapcount:0 mapping:0000000069d82f88 index:0x200 pfn:0x374ee
aops:shmem_aops ino:40b dentry name:"memfd:syzkaller"
flags: 0xfff0000008001e(referenced|uptodate|dirty|lru|swapbacked)
raw: 00fff0000008001e ffffea0000ca4a08 ffffea0000d8de88 ffff8880287936a8
raw: 0000000000000200 0000000000000000 00000001ffffffff ffff888010e00000
page dumped because: kasan: bad access detected
page->mem_cgroup:ffff888010e00000

Memory state around the buggy address:
 ffff8880374ee580: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880374ee600: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880374ee680: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                                              ^
 ffff8880374ee700: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880374ee780: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Maintainers
ci-upstream-kasan-gce-selinux-root	2020/11/23 20:55	upstream	418baf2c	878fb17a	.config	log	report	syz	C		anton@tuxera.com, linux-kernel@vger.kernel.org, linux-ntfs-dev@lists.sourceforge.net