linux-kernel - [syzbot] WARNING: refcount bug in memfd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <00000000000064451505cf0a3aa2@google.com>
Date:   Sat, 23 Oct 2021 12:35:19 -0700
From:   syzbot <syzbot+75639e6a0331cd61d3e2@...kaller.appspotmail.com>
To:     akpm@...ux-foundation.org, jordy@...dyzomer.github.io,
        jordy@...ing.systems, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, syzkaller-bugs@...glegroups.com,
        torvalds@...ux-foundation.org
Subject: [syzbot] WARNING: refcount bug in memfd_secret

Hello,

syzbot found the following issue on:

HEAD commit:    9c0c4d24ac00 Merge tag 'block-5.15-2021-10-22' of git://gi..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=115a0328b00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=59f3ef2b4077575
dashboard link: https://syzkaller.appspot.com/bug?extid=75639e6a0331cd61d3e2
compiler:       Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13a035c2b00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14ae869f300000

The issue was bisected to:

commit 110860541f443f950c1274f217a1a3e298670a33
Author: Jordy Zomer <jordy@...dyzomer.github.io>
Date:   Wed Sep 8 02:56:18 2021 +0000

    mm/secretmem: use refcount_t instead of atomic_t

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1433ea1cb00000
final oops:     https://syzkaller.appspot.com/x/report.txt?x=1633ea1cb00000
console output: https://syzkaller.appspot.com/x/log.txt?x=1233ea1cb00000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+75639e6a0331cd61d3e2@...kaller.appspotmail.com
Fixes: 110860541f44 ("mm/secretmem: use refcount_t instead of atomic_t")

------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 6529 at lib/refcount.c:25 refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25
Modules linked in:
CPU: 1 PID: 6529 Comm: syz-executor563 Not tainted 5.15.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0x13d/0x1a0 lib/refcount.c:25
Code: c7 80 e1 b3 8a 31 c0 e8 31 8e 3b fd 0f 0b eb a3 e8 b8 79 71 fd c6 05 43 86 b6 09 01 48 c7 c7 e0 e1 b3 8a 31 c0 e8 13 8e 3b fd <0f> 0b eb 85 e8 9a 79 71 fd c6 05 26 86 b6 09 01 48 c7 c7 40 e2 b3
RSP: 0018:ffffc900012dfed0 EFLAGS: 00010246
RAX: f8bc46cda99bde00 RBX: 0000000000000002 RCX: ffff88801e03d580
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: ffffffff81695fe2 R09: ffffed10173a57a8
R10: ffffed10173a57a8 R11: 0000000000000000 R12: ffff888078595180
R13: ffff88806f5e8030 R14: 0000000000000003 R15: dffffc0000000000
FS:  00005555558b2300(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ff91ea21000 CR3: 000000007077c000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __refcount_inc include/linux/refcount.h:250 [inline]
 refcount_inc include/linux/refcount.h:267 [inline]
 __do_sys_memfd_secret mm/secretmem.c:221 [inline]
 __se_sys_memfd_secret+0x2ea/0x350 mm/secretmem.c:194
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f09de6c7f79
Code: 28 c3 e8 2a 14 00 00 66 2e 0f 1f 84 00 00 00 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 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:00007ffe81d58a98 EFLAGS: 00000246 ORIG_RAX: 00000000000001bf
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f09de6c7f79
RDX: 00007f09de68ae83 RSI: 0000000000000012 RDI: 0000000000000000
RBP: 00007f09de68bf60 R08: 0000000000000000 R09: 0000000000000000
R10: 00000000ffffffff R11: 0000000000000246 R12: 00007f09de68bff0
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@...glegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches