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From: Greg KH <gregkh@linuxfoundation.org>
To: Martijn Coenen <maco@android.com>
Cc: john.stultz@linaro.org, tkjos@google.com, arve@android.com,
	linux-kernel@vger.kernel.org, devel@driverdev.osuosl.org,
	maco@google.com, ebiggers@google.com
Subject: Re: [PATCH] ANDROID: binder: remove waitqueue when thread exits.
Date: Fri, 5 Jan 2018 13:20:21 +0100	[thread overview]
Message-ID: <20180105122021.GF19551@kroah.com> (raw)
In-Reply-To: <20180105102707.261740-1-maco@android.com>

On Fri, Jan 05, 2018 at 11:27:07AM +0100, Martijn Coenen wrote:
> binder_poll() passes the thread->wait waitqueue that
> can be slept on for work. When a thread that uses
> epoll explicitly exits using BINDER_THREAD_EXIT,
> the waitqueue is freed, but it is never removed
> from the corresponding epoll data structure. When
> the process subsequently exits, the epoll cleanup
> code tries to access the waitlist, which results in
> a use-after-free.
> 
> Prevent this by using POLLFREE when the thread exits.
> 
> Signed-off-by: Martijn Coenen <maco@android.com>
> Reported-by: syzbot <syzkaller@googlegroups.com>
> ---
>  drivers/android/binder.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)

Should this be a 4.15-final thing, as well as backported to any range of
older kernels?

thanks,

greg k-h

  reply	other threads:[~2018-01-05 12:20 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-05 10:27 Martijn Coenen
2018-01-05 12:20 ` Greg KH [this message]
2018-01-05 12:54   ` Martijn Coenen

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