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From: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
To: serge@hallyn.com, Oleg Nesterov <oleg@redhat.com>
Cc: syzbot <syzbot+a9ac39bf55329e206219@syzkaller.appspotmail.com>,
	jmorris@namei.org, keescook@chromium.org,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	syzkaller-bugs@googlegroups.com
Subject: Re: KASAN: use-after-free Read in task_is_descendant
Date: Sun, 21 Oct 2018 16:12:43 +0900	[thread overview]
Message-ID: <bf1a083c-0d09-07fb-6ad2-4bf30ac49cd8@I-love.SAKURA.ne.jp> (raw)
In-Reply-To: <0000000000004904df0578b7d3da@google.com>

On 2018/10/21 16:10, syzbot wrote:
> BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:188 [inline]
> BUG: KASAN: use-after-free in task_is_descendant.part.2+0x610/0x670 security/yama/yama_lsm.c:295
> Read of size 8 at addr ffff8801c4666b20 by task syz-executor3/12722
> 
> CPU: 1 PID: 12722 Comm: syz-executor3 Not tainted 4.19.0-rc8+ #70
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
>  __dump_stack lib/dump_stack.c:77 [inline]
>  dump_stack+0x1c4/0x2b4 lib/dump_stack.c:113
>  print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
>  kasan_report_error mm/kasan/report.c:354 [inline]
>  kasan_report.cold.9+0x242/0x309 mm/kasan/report.c:412
>  __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
>  __read_once_size include/linux/compiler.h:188 [inline]
>  task_is_descendant.part.2+0x610/0x670 security/yama/yama_lsm.c:295

Do we need to hold

  write_lock_irq(&tasklist_lock);

rather than

  rcu_read_lock();

when accessing

  "struct task_struct"->real_parent

?

  reply	other threads:[~2018-10-21  7:13 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-21  7:10 KASAN: use-after-free Read in task_is_descendant syzbot
2018-10-21  7:12 ` Tetsuo Handa [this message]
2018-10-22  9:54   ` Oleg Nesterov
2018-10-22 10:06     ` Tetsuo Handa
2018-10-22 13:46       ` Oleg Nesterov
2018-10-25  2:15         ` Tetsuo Handa
2018-10-25 11:13           ` Oleg Nesterov
2018-10-25 11:36             ` Kees Cook
2018-10-25 12:05               ` Oleg Nesterov
2018-10-25 11:47             ` Tetsuo Handa
2018-10-25 12:17               ` Oleg Nesterov
2018-10-25 13:01                 ` Oleg Nesterov
2018-10-26 16:09                   ` Kees Cook
2018-10-29 12:23                     ` Oleg Nesterov
2018-10-29 15:05                       ` yama: unsafe usage of ptrace_relation->tracer Oleg Nesterov
2019-01-10 11:05                         ` Tetsuo Handa
2019-01-10 18:47                           ` Kees Cook
2019-01-16 17:40                           ` Oleg Nesterov
2018-10-25 13:14                 ` KASAN: use-after-free Read in task_is_descendant Tetsuo Handa
2018-10-25 15:55                   ` Oleg Nesterov
2018-10-25 16:25                     ` Oleg Nesterov
2018-10-26 12:23                     ` Tetsuo Handa
2018-10-26 13:04                       ` Oleg Nesterov
2018-10-26 13:51                         ` Tetsuo Handa
2018-10-26 14:39                           ` Oleg Nesterov
2018-10-26 15:04                             ` Tetsuo Handa
2018-10-26 15:22                               ` Oleg Nesterov
2018-10-25  8:19     ` Kees Cook
2018-10-25 11:52       ` Oleg Nesterov
2018-11-10  3:25 ` syzbot
2018-11-10 11:46 ` syzbot

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