Re: [IMA] Re: possible deadlock in get_user_pages_unlocked (2)

Re: [IMA] Re: possible deadlock in get_user_pages_unlocked (2)

[Eric Biggers]

On Mon, Jun 10, 2019 at 12:06:23PM -0700, Eric Biggers wrote:
> On Tue, Jun 04, 2019 at 06:16:00PM -0700, syzbot wrote:
> > syzbot has bisected this bug to:
> > 
> > commit 69d61f577d147b396be0991b2ac6f65057f7d445
> > Author: Mimi Zohar <zohar@linux.ibm.com>
> > Date:   Wed Apr 3 21:47:46 2019 +0000
> > 
> >     ima: verify mprotect change is consistent with mmap policy
> > 
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1055a2f2a00000
> > start commit:   56b697c6 Add linux-next specific files for 20190604
> > git tree:       linux-next
> > final crash:    https://syzkaller.appspot.com/x/report.txt?x=1255a2f2a00000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=1455a2f2a00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=4248d6bc70076f7d
> > dashboard link: https://syzkaller.appspot.com/bug?extid=e1374b2ec8f6a25ab2e5
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=165757eea00000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=10dd3e86a00000
> > 
> > Reported-by: syzbot+e1374b2ec8f6a25ab2e5@syzkaller.appspotmail.com
> > Fixes: 69d61f577d14 ("ima: verify mprotect change is consistent with mmap
> > policy")
> > 
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> > 
> 
> Hi Mimi, it seems your change to call ima_file_mmap() from
> security_file_mprotect() violates the locking order by taking i_rwsem while
> mmap_sem is held.
> 
> - Eric

This patch was dropped from linux-next, so let's invalidate the bug report.

#syz invalid

- Eric