linux-kernel - Re: [PATCH] fix infoleak in fcntl

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Message-ID: <572FA936.30802@nod.at>
Date:	Sun, 8 May 2016 23:01:42 +0200
From:	Richard Weinberger <richard@....at>
To:	Kangjie Lu <kangjielu@...il.com>
Cc:	Jeff Layton <jlayton@...chiereds.net>,
	Bruce Fields <bfields@...ldses.org>,
	Al Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Taesoo Kim <taesoo@...ech.edu>, Insu Yun <insu@...ech.edu>,
	Kangjie Lu <kjlu@...ech.edu>
Subject: Re: [PATCH] fix infoleak in fcntl

Am 08.05.2016 um 17:40 schrieb Kangjie Lu:
> 
> 
> On Sun, May 8, 2016 at 8:58 AM, Richard Weinberger <richard.weinberger@...il.com <mailto:richard.weinberger@...il.com>> wrote:
> 
>     On Tue, May 3, 2016 at 10:34 PM, Kangjie Lu <kangjielu@...il.com <mailto:kangjielu@...il.com>> wrote:
>     > The stack object “si” has a total size of 128 bytes; however, only
>     > 16 bytes are initialized. The remaining uninitialized bytes are
>     > sent to userland via send_signal.
> 
>     How did you find all these leaks?
>     Since you sent more than one patch I guess you used some tool, which one?
> 
> 
> Yes. Since there are *so many* infoleak vulnerabilities in the kernel, we are writing a
> static checker to find them.  We plan to release it once it is done, so people can use
> it to find more bugs in kernel or even other user space programs.

How does your tool work?
I'd guess it tries to find uninitialized structs passed into copy_to_user().

Thanks,
//richard