syzbot


KASAN: use-after-free Read in search_by_entry_key (2)

Status: fixed on 2021/09/10 21:17
Reported-by: syzbot+121dcf978ef5745e7d2d@syzkaller.appspotmail.com
Fix commit: df2f583b6363 reiserfs: add check for root_inode in reiserfs_fill_super
First crash: 628d, last: 478d

Fix bisection: fixed by (bisect log) :
commit df2f583b63637f9f882ba604cf23e0336de82220
Author: Yu Kuai <yukuai3@huawei.com>
Date: Fri Jul 2 04:07:43 2021 +0000

  reiserfs: add check for root_inode in reiserfs_fill_super

similar bugs (6):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in search_by_entry_key (2) C inconclusive inconclusive 14 11d 173d 0/24 upstream: reported C repro on 2022/06/12 10:38
linux-4.14 KASAN: use-after-free Read in search_by_entry_key (2) C error 5 11h14m 596d 0/1 upstream: reported C repro on 2021/04/16 06:17
linux-4.14 KASAN: use-after-free Read in search_by_entry_key C done 3 696d 802d 1/1 fixed on 2021/02/21 17:18
linux-4.19 KASAN: use-after-free Read in search_by_entry_key (3) C error 6 7d05h 169d 0/1 upstream: reported C repro on 2022/06/17 02:59
linux-4.19 KASAN: use-after-free Read in search_by_entry_key C done 1 697d 787d 1/1 fixed on 2021/02/20 09:47
upstream KASAN: use-after-free Read in search_by_entry_key C done 3 782d 785d 21/24 fixed on 2021/03/10 01:49

Sample crash report:
reiserfs: using flush barriers
REISERFS (device loop0): journal params: device loop0, size 15748, journal first block 18, max trans len 1024, max batch 900, max commit age 0, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using rupasov hash to sort names
==================================================================
BUG: KASAN: use-after-free in bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
BUG: KASAN: use-after-free in search_by_entry_key+0xcda/0xf30 fs/reiserfs/namei.c:164
Read of size 4 at addr ffff88808b258004 by task syz-executor259/8108

CPU: 0 PID: 8108 Comm: syz-executor259 Not tainted 4.19.180-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+0x1fc/0x2ef lib/dump_stack.c:118
 print_address_description.cold+0x54/0x219 mm/kasan/report.c:256
 kasan_report_error.cold+0x8a/0x1b9 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
 bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
 search_by_entry_key+0xcda/0xf30 fs/reiserfs/namei.c:164
 reiserfs_find_entry.part.0+0x142/0x1480 fs/reiserfs/namei.c:321
 reiserfs_find_entry fs/reiserfs/namei.c:367 [inline]
 reiserfs_lookup+0x24a/0x490 fs/reiserfs/namei.c:367
 __lookup_slow+0x246/0x4a0 fs/namei.c:1672
 lookup_one_len+0x163/0x190 fs/namei.c:2544
 reiserfs_lookup_privroot+0x92/0x280 fs/reiserfs/xattr.c:970
 reiserfs_fill_super+0x13ea/0x2cf0 fs/reiserfs/super.c:2197
 mount_bdev+0x2fc/0x3b0 fs/super.c:1158
 mount_fs+0xa3/0x310 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+0x113c/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+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x44622a
Code: 48 c7 c2 c0 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 a8 00 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffde14f4358 EFLAGS: 00000286 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffde14f43b0 RCX: 000000000044622a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffde14f4370
RBP: 00007ffde14f4370 R08: 00007ffde14f43b0 R09: 0000000000000000
R10: 0000000000208403 R11: 0000000000000286 R12: 0000000000000004
R13: 0000000000000003 R14: 0000000000000003 R15: 0000000000000004

The buggy address belongs to the page:
page:ffffea00022c9600 count:0 mapcount:0 mapping:0000000000000000 index:0x1
flags: 0xfff00000000000()
raw: 00fff00000000000 ffffea00022c9648 ffff8880ba02ea08 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808b257f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808b257f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808b258000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff88808b258080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88808b258100: 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 2021/03/14 15:18 linux-4.19.y 030194a5b292 4a003785 .config log report syz C KASAN: use-after-free Read in search_by_entry_key
ci2-linux-4-19 2021/03/14 15:00 linux-4.19.y 030194a5b292 4a003785 .config log report info KASAN: use-after-free Read in search_by_entry_key
* Struck through repros no longer work on HEAD.