Re: [Linux-NTFS-Dev] [syzbot] KASAN: use-after-free Read in ntfs_attr_find

[Siddh R. P. <co...@si...>]

On Thu, 25 Aug 2022 23:55:35 +0530  syzbot  wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    c40e8341e3b3 Merge tag 'cgroup-for-6.0-rc2-fixes' of git:/..
> git tree:       upstream
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=161114c7080000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=911efaff115942bb
> dashboard link: https://syzkaller.appspot.com/bug?extid=5f8dcabe4a3b2c51c607
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14dd8265080000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=11f30033080000
> 
> The issue was bisected to:
> 
> commit 38c9c22a85aeed28d0831f230136e9cf6fa2ed44
> Author: ChenXiaoSong che...@hu...>
> Date:   Thu Jul 7 10:53:29 2022 +0000
> 
>     ntfs: fix use-after-free in ntfs_ucsncmp()
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=16f6cd8d080000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=15f6cd8d080000
> console output: https://syzkaller.appspot.com/x/log.txt?x=11f6cd8d080000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syz...@sy...
> Fixes: 38c9c22a85ae ("ntfs: fix use-after-free in ntfs_ucsncmp()")

This is incorrect. The issue is caused by:
9b75450d6c58 ("fs/ntfs3: Fix memory leak if fill_super failed")

The fix for this can be seen by the two different patches tested by syzbot, which
are listed on the dashboard.

Thanks,
Siddh