From: Willy Tarreau <w@1wt.eu>
To: Kees Cook <keescook@chromium.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, yalin wang <yalin.wang2010@gmail.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] fs: clear file privilege bits when mmap writing
Date: Thu, 10 Dec 2015 08:10:22 +0100 [thread overview]
Message-ID: <20151210071022.GA31969@1wt.eu> (raw)
In-Reply-To: <20151210070635.GC31922@1wt.eu>
On Thu, Dec 10, 2015 at 08:06:35AM +0100, Willy Tarreau wrote:
> Hi Kees,
>
> Why not add a new file flag instead ?
>
> Something like this (editing your patch by hand to illustrate) :
(...)
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 3aa514254161..409bd7047e7e 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -913,3 +913,4 @@
> #define FL_OFDLCK 1024 /* lock is "owned" by struct file */
> #define FL_LAYOUT 2048 /* outstanding pNFS layout */
> +#define FL_DROP_PRIVS 4096 /* lest something weird decides that 2 is OK */
Crap, these ones are for locks, we need to use O_* instead
But anyway you get the idea, I mean there are probably many spare bits
overthere.
Another option I was thinking about was to change f_mode and detect the
change on close. But I don't know what to compare it against.
Willy
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next prev parent reply other threads:[~2015-12-10 7:10 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-09 22:51 [PATCH v5] fs: clear file privilege bits when mmap writing Kees Cook
2015-12-10 1:21 ` Christoph Hellwig
2015-12-10 3:25 ` Kees Cook
2015-12-10 4:14 ` Al Viro
2015-12-10 7:06 ` Willy Tarreau
2015-12-10 7:10 ` Willy Tarreau [this message]
2015-12-10 18:05 ` Kees Cook
2015-12-10 18:16 ` Willy Tarreau
2015-12-10 18:18 ` Kees Cook
2015-12-10 19:33 ` Al Viro
2015-12-10 19:47 ` Kees Cook
2015-12-10 20:27 ` Al Viro
2015-12-10 21:45 ` Kees Cook
2015-12-10 21:56 ` Al Viro
2015-12-10 22:00 ` Kees Cook
-- strict thread matches above, loose matches on Subject: below --
2015-12-10 22:33 Kees Cook
2016-01-07 19:36 ` Kees Cook
2016-01-08 0:30 ` Andy Lutomirski
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