syzbot


KASAN: use-after-free Read in ntfs_read_locked_inode

Status: fixed on 2021/03/24 11:10
Reported-by: syzbot+9016e2b4812b0bba3879@syzkaller.appspotmail.com
Fix commit: 23e895868b51 ntfs: check for valid standard information attribute
First crash: 805d, last: 655d

Fix bisection: fixed by (bisect log) :
commit 23e895868b518f48eab7925aeb93aeeac3ac2594
Author: Rustam Kovhaev <rkovhaev@gmail.com>
Date: Wed Feb 24 20:00:30 2021 +0000

  ntfs: check for valid standard information attribute

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_read_locked_inode C done 2 658d 810d 1/1 fixed on 2021/03/22 03:02
upstream KASAN: use-after-free Read in ntfs_read_locked_inode C done done 4 793d 1709d 0/24 upstream: reported C repro on 2018/04/05 04:02

Sample crash report:
ntfs: (device loop0): ntfs_read_locked_inode(): Failed with error code -5.  Marking corrupt inode 0xa as bad.  Run chkdsk.
ntfs: (device loop0): load_and_init_upcase(): Failed to load $UpCase from the volume. Using default.
==================================================================
BUG: KASAN: use-after-free in ntfs_read_locked_inode+0x4731/0x5490 fs/ntfs/inode.c:670
Read of size 8 at addr ffff8880819a46cd by task syz-executor611/6497

CPU: 1 PID: 6497 Comm: syz-executor611 Not tainted 4.19.150-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+0x22c/0x33e lib/dump_stack.c:118
 print_address_description.cold+0x56/0x25c mm/kasan/report.c:256
 kasan_report_error.cold+0x66/0xb9 mm/kasan/report.c:354
 kasan_report mm/kasan/report.c:412 [inline]
 __asan_report_load_n_noabort+0x8b/0xa0 mm/kasan/report.c:443
 ntfs_read_locked_inode+0x4731/0x5490 fs/ntfs/inode.c:670
 ntfs_iget+0x12d/0x180 fs/ntfs/inode.c:190
 load_and_init_attrdef fs/ntfs/super.c:1603 [inline]
 load_system_files fs/ntfs/super.c:1831 [inline]
 ntfs_fill_super+0x22b0/0x89d2 fs/ntfs/super.c:2908
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x318 fs/super.c:1261
 vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
 vfs_kern_mount fs/namespace.c:951 [inline]
 do_new_mount fs/namespace.c:2469 [inline]
 do_mount+0x51c/0x2f10 fs/namespace.c:2799
 ksys_mount+0xcf/0x130 fs/namespace.c:3015
 __do_sys_mount fs/namespace.c:3029 [inline]
 __se_sys_mount fs/namespace.c:3026 [inline]
 __x64_sys_mount+0xba/0x150 fs/namespace.c:3026
 do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45761a
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ed 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 ca a3 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007ffcd49d7368 EFLAGS: 00000287 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffcd49d73c0 RCX: 000000000045761a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffcd49d7380
RBP: 0000000000000004 R08: 00007ffcd49d73c0 R09: 0000000000316777
R10: 0000000000000000 R11: 0000000000000287 R12: 0000000000000003
R13: 00007ffcd49d7380 R14: 0000000000000000 R15: 0000000020001230

The buggy address belongs to the page:
page:ffffea0002066900 count:0 mapcount:0 mapping:0000000000000000 index:0x1
flags: 0xfffe0000000000()
raw: 00fffe0000000000 ffffea0002066948 ffffea00020668c8 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880819a4580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880819a4600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880819a4680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8880819a4700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880819a4780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (2):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-19 2020/10/15 01:13 linux-4.19.y a1b977b49b66 fc7735a2 .config log report syz C
ci2-linux-4-19 2020/09/25 09:40 linux-4.19.y d09b80172c22 54289b08 .config log report syz C
* Struck through repros no longer work on HEAD.