From: Dan Carpenter <error27@gmail.com>
To: Vasiliy Kulikov <segooon@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>,
kernel-janitors@vger.kernel.org,
Greg Kroah-Hartman <gregkh@suse.de>,
Alan Cox <alan@linux.intel.com>, Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/8] char: synclink: fix information leak to userland
Date: Sun, 17 Oct 2010 17:36:09 +0000 [thread overview]
Message-ID: <20101017173609.GS6614@bicker> (raw)
In-Reply-To: <20101017153839.GA11029@albatros>
On Sun, Oct 17, 2010 at 07:38:39PM +0400, Vasiliy Kulikov wrote:
> On Sun, Oct 17, 2010 at 17:34 +0200, Jiri Slaby wrote:
> > On 10/17/2010 04:41 PM, Vasiliy Kulikov wrote:
> > > Structure new_line is copied to userland with some padding fields unitialized.
> > > It leads to leaking of stack memory.
> >
> > I think your tool has a bug. I must admit I fail to see the padding
> > which would cause leaks. Could you elaborate?
>
> I didn't use any tool except "grep copy_to_user" :)
>
It seems like you should be able to use pahole to make a list of
structs with padding and then a checker script to find places where
information is leaked.
Also someone complained to me about when I added a memset() in a fast
path. The thought was that it might be faster to just initialize it
instead like:
struct foo bar = {};
In my case just using the initializer made the code cleaner so I did it,
but neither of us actually benchmarked it.
regards,
dan carpenter
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <error27@gmail.com>
To: Vasiliy Kulikov <segooon@gmail.com>
Cc: Jiri Slaby <jslaby@suse.cz>,
kernel-janitors@vger.kernel.org,
Greg Kroah-Hartman <gregkh@suse.de>,
Alan Cox <alan@linux.intel.com>, Arnd Bergmann <arnd@arndb.de>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 6/8] char: synclink: fix information leak to userland
Date: Sun, 17 Oct 2010 19:36:09 +0200 [thread overview]
Message-ID: <20101017173609.GS6614@bicker> (raw)
In-Reply-To: <20101017153839.GA11029@albatros>
On Sun, Oct 17, 2010 at 07:38:39PM +0400, Vasiliy Kulikov wrote:
> On Sun, Oct 17, 2010 at 17:34 +0200, Jiri Slaby wrote:
> > On 10/17/2010 04:41 PM, Vasiliy Kulikov wrote:
> > > Structure new_line is copied to userland with some padding fields unitialized.
> > > It leads to leaking of stack memory.
> >
> > I think your tool has a bug. I must admit I fail to see the padding
> > which would cause leaks. Could you elaborate?
>
> I didn't use any tool except "grep copy_to_user" :)
>
It seems like you should be able to use pahole to make a list of
structs with padding and then a checker script to find places where
information is leaked.
Also someone complained to me about when I added a memset() in a fast
path. The thought was that it might be faster to just initialize it
instead like:
struct foo bar = {};
In my case just using the initializer made the code cleaner so I did it,
but neither of us actually benchmarked it.
regards,
dan carpenter
next prev parent reply other threads:[~2010-10-17 17:36 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-17 14:41 [PATCH 6/8] char: synclink: fix information leak to userland Vasiliy Kulikov
2010-10-17 14:41 ` Vasiliy Kulikov
2010-10-17 15:34 ` Jiri Slaby
2010-10-17 15:34 ` Jiri Slaby
2010-10-17 15:38 ` Vasiliy Kulikov
2010-10-17 15:38 ` Vasiliy Kulikov
2010-10-17 17:36 ` Dan Carpenter [this message]
2010-10-17 17:36 ` Dan Carpenter
2010-10-17 17:50 ` Vasiliy Kulikov
2010-10-17 17:50 ` Vasiliy Kulikov
2010-10-17 17:46 ` Jiri Slaby
2010-10-17 17:46 ` Jiri Slaby
2010-10-17 17:55 ` Vasiliy Kulikov
2010-10-17 17:55 ` Vasiliy Kulikov
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