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Date: Wed, 4 May 2016 12:38:52 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: Kangjie Lu <kangjielu@gmail.com>
Cc: akpm@linux-foundation.org, peterz@infradead.org, amanieu@gmail.com,
        linux-kernel@vger.kernel.org, taesoo@gatech.edu, insu@gatech.edu,
        Kangjie Lu <kjlu@gatech.edu>
Subject: Re: [PATCH] infoleak fix1 in signal
Message-ID: <20160504103851.GA6977@redhat.com>
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On 05/03, Kangjie Lu wrote:
>
> The stack object “info” has a total size of 128 bytes; however,
> only 28 bytes are initialized. The remaining uninitialized bytes
> are sent to userland via send_signal.

Not really, please see copy_siginfo_to_user(), case(__SI_CHLD). All members
copied to user-space are initialized afaics.

> @@ -1594,6 +1594,7 @@ bool do_notify_parent(struct task_struct *tsk, int sig)
>  			sig = SIGCHLD;
>  	}
>
> +	memset(&info, 0, sizeof(info));

looks like a false alarm to me.

Oleg.