syzbot


KASAN: use-after-free Read in ntfs_read_locked_inode

Status: fixed on 2021/03/22 03:02
Reported-by: syzbot+002e6becd6fcd67332f2@syzkaller.appspotmail.com
Fix commit: 49ee014a2070 ntfs: check for valid standard information attribute
First crash: 800d, last: 649d

Fix bisection: fixed by (bisect log) :
commit 49ee014a2070b209fd73ad96a7a36193dcdd149c
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-4.19 KASAN: use-after-free Read in ntfs_read_locked_inode C done 2 646d 796d 1/1 fixed on 2021/03/24 11:10
upstream KASAN: use-after-free Read in ntfs_read_locked_inode C done done 4 784d 1700d 0/24 upstream: reported C repro on 2018/04/05 04:02

Sample crash report:
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+0x425a/0x5000 fs/ntfs/inode.c:677
Read of size 8 at addr ffff8880805b06cd by task syz-executor128/6394

CPU: 1 PID: 6394 Comm: syz-executor128 Not tainted 4.14.198-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+0x1b2/0x283 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x194 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load_n_noabort+0x6b/0x80 mm/kasan/report.c:440
 ntfs_read_locked_inode+0x425a/0x5000 fs/ntfs/inode.c:677
 ntfs_iget+0xfa/0x130 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+0x1ffb/0x7170 fs/ntfs/super.c:2908
 mount_bdev+0x2b3/0x360 fs/super.c:1134
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2549 [inline]
 do_mount+0xe53/0x2a00 fs/namespace.c:2879
 SYSC_mount fs/namespace.c:3095 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3072
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x44954a
RSP: 002b:00007fff08421368 EFLAGS: 00000287 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fff084213c0 RCX: 000000000044954a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fff08421380
RBP: 00007fff08421380 R08: 00007fff084213c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000287 R12: 00000000000000ac
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

The buggy address belongs to the page:
page:ffffea0002016c00 count:0 mapcount:0 mapping:          (null) index:0x1
flags: 0xfffe0000000000()
raw: 00fffe0000000000 0000000000000000 0000000000000001 00000000ffffffff
raw: ffffea0002017920 ffffea00020c7b20 0000000000000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880805b0580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880805b0600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff8880805b0680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                              ^
 ffff8880805b0700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8880805b0780: 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-4-14 2020/10/02 10:34 linux-4.14.y cbfa1702aaf6 9602ddf4 .config log report syz C
ci2-linux-4-14 2020/09/20 22:16 linux-4.14.y cbfa1702aaf6 9564d2e9 .config log report syz C
* Struck through repros no longer work on HEAD.