syzbot


KASAN: use-after-free Read in search_by_entry_key

Status: fixed on 2021/03/10 01:49
Reported-by: syzbot+83b6f7cf9922cae5c4d7@syzkaller.appspotmail.com
Fix commit: d24396c5290b reiserfs: add check for an invalid ih_entry_count
First crash: 786d, last: 782d

Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: WARNING in sysfs_warn_dup (log)
Repro: C syz .config
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 12h21m 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 7d06h 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
linux-4.19 KASAN: use-after-free Read in search_by_entry_key (2) C done 2 478d 628d 1/1 fixed on 2021/09/10 21:17
Patch testing requests:
Created Duration User Patch Repo Result
2020/11/01 07:35 18m rkovhaev@gmail.com patch upstream OK
2020/10/31 21:54 19m rkovhaev@gmail.com patch upstream OK
2020/10/20 12:07 11m anmol.karan123@gmail.com patch upstream report log
2020/10/11 16:15 10m rkovhaev@gmail.com upstream report log

Sample crash report:
REISERFS (device loop0): journal params: device loop0, size 15748, journal first block 18, max trans len 256, max batch 225, max commit age 30, max trans age 30
REISERFS (device loop0): checking transaction log (loop0)
REISERFS (device loop0): Using tea hash to sort names
REISERFS (device loop0): using 3.5.x disk format
==================================================================
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+0x81f/0x960 fs/reiserfs/namei.c:164
Read of size 4 at addr ffff88807d41e7bd by task syz-executor210/6891

CPU: 1 PID: 6891 Comm: syz-executor210 Not tainted 5.9.0-rc8-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+0x198/0x1fd lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 bin_search_in_dir_item fs/reiserfs/namei.c:40 [inline]
 search_by_entry_key+0x81f/0x960 fs/reiserfs/namei.c:164
 reiserfs_find_entry.part.0+0x139/0xdf0 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+0x24c/0x480 fs/namei.c:1544
 lookup_one_len+0x163/0x190 fs/namei.c:2562
 reiserfs_lookup_privroot+0x92/0x280 fs/reiserfs/xattr.c:972
 reiserfs_fill_super+0x211b/0x2df3 fs/reiserfs/super.c:2176
 mount_bdev+0x32e/0x3f0 fs/super.c:1417
 legacy_get_tree+0x105/0x220 fs/fs_context.c:592
 vfs_get_tree+0x89/0x2f0 fs/super.c:1547
 do_new_mount fs/namespace.c:2875 [inline]
 path_mount+0x1387/0x20a0 fs/namespace.c:3192
 do_mount fs/namespace.c:3205 [inline]
 __do_sys_mount fs/namespace.c:3413 [inline]
 __se_sys_mount fs/namespace.c:3390 [inline]
 __x64_sys_mount+0x27f/0x300 fs/namespace.c:3390
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x447d9a
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:00007ffe3d8a0238 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007ffe3d8a0290 RCX: 0000000000447d9a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffe3d8a0250
RBP: 00007ffe3d8a0250 R08: 00007ffe3d8a0290 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000297 R12: 0000000000000006
R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003

The buggy address belongs to the page:
page:00000000b141154e refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x7d41e
flags: 0xfffe0000000000()
raw: 00fffe0000000000 ffffea0001f507c8 ffff8880ae539608 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88807d41e680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807d41e700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88807d41e780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                        ^
 ffff88807d41e800: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88807d41e880: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================

Crashes (3):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-kasan-gce-root 2020/10/12 06:59 upstream 3dd0130f2430 4a77ae0b .config log report syz C
ci-upstream-kasan-gce-selinux-root 2020/10/11 10:09 upstream da690031a5d6 4a77ae0b .config log report syz C
ci-upstream-kasan-gce-smack-root 2020/10/08 09:26 upstream c85fb28b6f99 1880b4a9 .config log report syz C
* Struck through repros no longer work on HEAD.