linux-kernel - Re: [syzbot] KMSAN: kernel-infoleak in ucma_init_qp

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-prev] [day] [month] [year] [list]

Message-ID: <YdQydxgthE47Xhab@unreal>
Date:   Tue, 4 Jan 2022 13:41:43 +0200
From:   Leon Romanovsky <leon@...nel.org>
To:     syzbot <syzbot+6d532fa8f9463da290bc@...kaller.appspotmail.com>
Cc:     glider@...gle.com, jgg@...pe.ca, liangwenpeng@...wei.com,
        linux-kernel@...r.kernel.org, linux-rdma@...r.kernel.org,
        liweihang@...wei.com, syzkaller-bugs@...glegroups.com,
        tanxiaofei@...wei.com, yuehaibing@...wei.com
Subject: Re: [syzbot] KMSAN: kernel-infoleak in ucma_init_qp_attr

On Tue, Jan 04, 2022 at 02:03:17AM -0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    81c325bbf94e kmsan: hooks: do not check memory in kmsan_in..
> git tree:       https://github.com/google/kmsan.git master
> console output: https://syzkaller.appspot.com/x/log.txt?x=10c4260db00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=2d8b9a11641dc9aa
> dashboard link: https://syzkaller.appspot.com/bug?extid=6d532fa8f9463da290bc
> compiler:       clang version 14.0.0 (/usr/local/google/src/llvm-git-monorepo 2b554920f11c8b763cd9ed9003f4e19b919b8e1f), GNU ld (GNU Binutils for Debian) 2.35.2
> userspace arch: i386
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+6d532fa8f9463da290bc@...kaller.appspotmail.com
> 
> =====================================================
> BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:121 [inline]
> BUG: KMSAN: kernel-infoleak in _copy_to_user+0x1c9/0x270 lib/usercopy.c:33
>  instrument_copy_to_user include/linux/instrumented.h:121 [inline]
>  _copy_to_user+0x1c9/0x270 lib/usercopy.c:33
>  copy_to_user include/linux/uaccess.h:209 [inline]
>  ucma_init_qp_attr+0x8c7/0xb10 drivers/infiniband/core/ucma.c:1242
>  ucma_write+0x637/0x6c0 drivers/infiniband/core/ucma.c:1732
>  vfs_write+0x8ce/0x2030 fs/read_write.c:588
>  ksys_write+0x28b/0x510 fs/read_write.c:643
>  __do_sys_write fs/read_write.c:655 [inline]
>  __se_sys_write fs/read_write.c:652 [inline]
>  __ia32_sys_write+0xdb/0x120 fs/read_write.c:652
>  do_syscall_32_irqs_on arch/x86/entry/common.c:114 [inline]
>  __do_fast_syscall_32+0x96/0xf0 arch/x86/entry/common.c:180
>  do_fast_syscall_32+0x34/0x70 arch/x86/entry/common.c:205
>  do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:248
>  entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
> 
> Local variable resp created at:
>  ucma_init_qp_attr+0xa4/0xb10 drivers/infiniband/core/ucma.c:1214
>  ucma_write+0x637/0x6c0 drivers/infiniband/core/ucma.c:1732
> 
> Bytes 40-59 of 144 are uninitialized
> Memory access of size 144 starts at ffff888167523b00
> Data copied to user address 0000000020000100
> 
> CPU: 1 PID: 25910 Comm: syz-executor.1 Not tainted 5.16.0-rc5-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> =====================================================

We are not clearing GRH fields in ib_copy_ah_attr_to_user() if dst->is_global is not set.
I'm testing the fix now and will post the patch after it will pass CI.

Thanks

> 
> 
> ---
> 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.