| 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
| ||
|
Message-ID: <7bf896d6-0cff-4be8-98db-8befa11cb6bc@gmail.com>
Date: Tue, 31 Dec 2024 14:20:21 +0100
From: Eric Dumazet <eric.dumazet@...il.com>
To: syzbot <syzbot+43f6243d6c4946b26405@...kaller.appspotmail.com>
Cc: linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
miklos@...redi.hu, syzkaller-bugs@...glegroups.com, viro@...iv.linux.org.uk
Subject: Re: [syzbot] [fuse?] BUG: unable to handle kernel NULL pointer
dereference in fuse_copy_one
On 12/31/24 2:17 PM, syzbot wrote:
>> On 12/31/24 2:10 PM, syzbot wrote:
>>> Hello,
>>>
>>> syzbot found the following issue on:
>>>
>>> HEAD commit: ccb98ccef0e5 Merge tag 'platform-drivers-x86-v6.13-4' of g..
>>> git tree: upstream
>>> console output: https://syzkaller.appspot.com/x/log.txt?x=14d4f50f980000
>>> kernel config: https://syzkaller.appspot.com/x/.config?x=86dd15278dbfe19f
>>> dashboard link: https://syzkaller.appspot.com/bug?extid=43f6243d6c4946b26405
>>> compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
>>> userspace arch: i386
>>>
>>> Unfortunately, I don't have any reproducer for this issue yet.
>>>
>>> Downloadable assets:
>>> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-ccb98cce.raw.xz
>>> vmlinux: https://storage.googleapis.com/syzbot-assets/75a6223b351c/vmlinux-ccb98cce.xz
>>> kernel image: https://storage.googleapis.com/syzbot-assets/beea89d50f58/bzImage-ccb98cce.xz
>>>
>>> IMPORTANT: if you fix the issue, please add the following tag to the commit:
>>> Reported-by: syzbot+43f6243d6c4946b26405@...kaller.appspotmail.com
>>>
>>> BUG: kernel NULL pointer dereference, address: 0000000000000000
>>> #PF: supervisor write access in kernel mode
>>> #PF: error_code(0x0002) - not-present page
>>> PGD 6a754067 P4D 6a754067 PUD 68142067 PMD 0
>>> Oops: Oops: 0002 [#1] PREEMPT SMP KASAN NOPTI
>>> CPU: 0 UID: 0 PID: 7523 Comm: syz.2.395 Not tainted 6.13.0-rc5-syzkaller-00004-gccb98ccef0e5 #0
>>> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
>>> RIP: 0010:memcpy+0xc/0x20 arch/x86/lib/memcpy_64.S:38
>>> Code: e9 44 fd ff ff 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 48 89 f8 48 89 d1 <f3> a4 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90
>>> RSP: 0018:ffffc9000370f8b0 EFLAGS: 00010293
>>> RAX: 0000000000000000 RBX: ffffc9000370fc50 RCX: 0000000000000004
>>> RDX: 0000000000000004 RSI: ffff88804ef5d710 RDI: 0000000000000000
>>> RBP: 0000000000000004 R08: 0000000000000005 R09: 0000000000000000
>>> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000004
>>> R13: 0000000000000000 R14: 0000000000000004 R15: dffffc0000000000
>>> FS: 0000000000000000(0000) GS:ffff88802b400000(0063) knlGS:00000000f5080b40
>>> CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
>>> CR2: 0000000000000000 CR3: 000000006ba72000 CR4: 0000000000352ef0
>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>>> Call Trace:
>>> <TASK>
>>> fuse_copy_do fs/fuse/dev.c:809 [inline]
>>> fuse_copy_one+0x1cc/0x230 fs/fuse/dev.c:1065
>>> fuse_copy_args+0x109/0x690 fs/fuse/dev.c:1083
>>> copy_out_args fs/fuse/dev.c:1966 [inline]
>>> fuse_dev_do_write+0x1b0a/0x3100 fs/fuse/dev.c:2052
>>> fuse_dev_write+0x160/0x1f0 fs/fuse/dev.c:2087
>>> new_sync_write fs/read_write.c:586 [inline]
>>> vfs_write+0x5ae/0x1150 fs/read_write.c:679
>>> ksys_write+0x12b/0x250 fs/read_write.c:731
>>> do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
>>> __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
>>> do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
>>> entry_SYSENTER_compat_after_hwframe+0x84/0x8e
>>> RIP: 0023:0xf708e579
>>> Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
>>> RSP: 002b:00000000f5080500 EFLAGS: 00000293 ORIG_RAX: 0000000000000004
>>> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000020000700
>>> RDX: 0000000000000014 RSI: 00000000f73c3ff4 RDI: 0000000000000000
>>> RBP: 0000000020008380 R08: 0000000000000000 R09: 0000000000000000
>>> R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
>>> R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
>>> </TASK>
>>> Modules linked in:
>>> CR2: 0000000000000000
>>> ---[ end trace 0000000000000000 ]---
>>> RIP: 0010:memcpy+0xc/0x20 arch/x86/lib/memcpy_64.S:38
>>> Code: e9 44 fd ff ff 66 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 48 89 f8 48 89 d1 <f3> a4 c3 cc cc cc cc 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90
>>> RSP: 0018:ffffc9000370f8b0 EFLAGS: 00010293
>>> RAX: 0000000000000000 RBX: ffffc9000370fc50 RCX: 0000000000000004
>>> RDX: 0000000000000004 RSI: ffff88804ef5d710 RDI: 0000000000000000
>>> RBP: 0000000000000004 R08: 0000000000000005 R09: 0000000000000000
>>> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000004
>>> R13: 0000000000000000 R14: 0000000000000004 R15: dffffc0000000000
>>> FS: 0000000000000000(0000) GS:ffff88802b400000(0063) knlGS:00000000f5080b40
>>> CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
>>> CR2: 0000000000000000 CR3: 000000006ba72000 CR4: 0000000000352ef0
>>> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
>>> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>>> ----------------
>>> Code disassembly (best guess):
>>> 0: e9 44 fd ff ff jmp 0xfffffd49
>>> 5: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
>>> c: 00 00
>>> e: 90 nop
>>> f: 90 nop
>>> 10: 90 nop
>>> 11: 90 nop
>>> 12: 90 nop
>>> 13: 90 nop
>>> 14: 90 nop
>>> 15: 90 nop
>>> 16: 90 nop
>>> 17: 90 nop
>>> 18: 90 nop
>>> 19: 90 nop
>>> 1a: 90 nop
>>> 1b: 90 nop
>>> 1c: 90 nop
>>> 1d: 90 nop
>>> 1e: f3 0f 1e fa endbr64
>>> 22: 66 90 xchg %ax,%ax
>>> 24: 48 89 f8 mov %rdi,%rax
>>> 27: 48 89 d1 mov %rdx,%rcx
>>> * 2a: f3 a4 rep movsb %ds:(%rsi),%es:(%rdi) <-- trapping instruction
>>> 2c: c3 ret
>>> 2d: cc int3
>>> 2e: cc int3
>>> 2f: cc int3
>>> 30: cc int3
>>> 31: 66 66 2e 0f 1f 84 00 data16 cs nopw 0x0(%rax,%rax,1)
>>> 38: 00 00 00 00
>>> 3c: 66 90 xchg %ax,%ax
>>> 3e: 90 nop
>>> 3f: 90 nop
>>>
>>>
>>> ---
>>> 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.
>>>
>>> If the report is already addressed, let syzbot know by replying with:
>>> #syz fix: exact-commit-title
>>>
>>> If you want to overwrite report's subsystems, reply with:
>>> #syz set subsystems: new-subsystem
>>> (See the list of subsystem names on the web dashboard)
>>>
>>> If the report is a duplicate of another one, reply with:
>>> #syz dup: exact-subject-of-another-report
>>>
>>> If you want to undo deduplication, reply with:
>>> #syz undup
>>>
>> Bug origin in
>>
>> commit ebe559609d7829b52c6642b581860760984faf9d
>> Author: Al Viro <viro@...iv.linux.org.uk>
>> Date: Fri Nov 15 10:30:14 2024 -0500
>>
>> fs: get rid of __FMODE_NONOTIFY kludge
>>
>> #syz test
> This crash does not have a reproducer. I cannot test it.
Right, I sent this (probably correct) patch on the wrong syzbot report.
>> diff --git a/fs/notify/fanotify/fanotify_user.c
>> b/fs/notify/fanotify/fanotify_user.c
>> index 19435cd2c41f..6ff94e312232 100644
>> --- a/fs/notify/fanotify/fanotify_user.c
>> +++ b/fs/notify/fanotify/fanotify_user.c
>> @@ -1624,8 +1624,8 @@ SYSCALL_DEFINE2(fanotify_init, unsigned int,
>> flags, unsigned int, event_f_flags)
>> file = anon_inode_getfile_fmode("[fanotify]", &fanotify_fops,
>> group,
>> f_flags, FMODE_NONOTIFY);
>> if (IS_ERR(file)) {
>> - fd = PTR_ERR(file);
>> put_unused_fd(fd);
>> + fd = PTR_ERR(file);
>> goto out_destroy_group;
>> }
>> fd_install(fd, file);
>>
Powered by blists - more mailing lists