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From: Al Viro <viro@ZenIV.linux.org.uk>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Willy Tarreau <w@1wt.eu>,
	"security@kernel.org" <security@kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Linux FS Devel <linux-fsdevel@vger.kernel.org>,
	Brad Spengler <spender@grsecurity.net>
Subject: Re: [PATCH v2] vfs: Tighten up linkat(..., AT_EMPTY_PATH)
Date: Sun, 25 Aug 2013 15:23:07 +0100	[thread overview]
Message-ID: <20130825142307.GA27005@ZenIV.linux.org.uk> (raw)
In-Reply-To: <CALCETrViJ8i3ty8xAECC0nqRuepVeKsW9r2W51tTCDUuB3V25g@mail.gmail.com>

On Sun, Aug 25, 2013 at 12:26:34AM -0700, Andy Lutomirski wrote:

> I think this is more screwed up than just flink and open.  For example:
> 
> $ echo 'WTF' >test
> $ truncate -s 1 /proc/self/fd/3 3<test
> $ cat test
> W$
> 
> IMO that should have failed.

Why?  truncate() always follows links, so what's the problem with that
one?  That you get checks of truncate() and not ftruncate()?

> In an ideal world (I think) ffrob(N), frobat(N, "", AT_EMPTY_PATH),
> and frobat(AT_FDCWD, "/proc/self/fd/N) should generally do the same
> thing.

What about the cases where frob() and ffrob() check for different things?

  reply	other threads:[~2013-08-25 14:23 UTC|newest]

Thread overview: 66+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-21 19:14 [PATCH v2] vfs: Tighten up linkat(..., AT_EMPTY_PATH) Andy Lutomirski
     [not found] ` <CA+55aFxi-ps2f2M8xPhfbuQ0pToqupPrDsLi2+GPUK2sqdYfUw@mail.gmail.com>
     [not found]   ` <CALCETrW7+LcexA6v6RQDKhni_yJAduOmiSDneCpq3v8sPDvwUQ@mail.gmail.com>
2013-08-21 20:16     ` Willy Tarreau
2013-08-22 18:48 ` Linus Torvalds
2013-08-22 18:53   ` Willy Tarreau
2013-08-22 19:05     ` Andy Lutomirski
2013-08-22 19:23       ` Linus Torvalds
2013-08-22 20:10         ` Andy Lutomirski
2013-08-22 20:15           ` Willy Tarreau
2013-08-22 20:22             ` Andy Lutomirski
2013-08-22 20:44               ` Linus Torvalds
2013-08-22 20:48                 ` Andy Lutomirski
2013-08-22 20:54                   ` Linus Torvalds
2013-08-22 20:58                     ` Andy Lutomirski
2013-08-23  1:07                     ` Al Viro
2013-08-25  3:37                       ` Al Viro
2013-08-25  7:26                         ` Andy Lutomirski
2013-08-25 14:23                           ` Al Viro [this message]
2013-08-25 17:04                             ` Andy Lutomirski
2013-08-25 19:57                         ` Linus Torvalds
2013-08-25 20:06                           ` Al Viro
2013-08-25 20:23                             ` Linus Torvalds
2013-08-26 17:37                               ` Linus Torvalds
2013-08-26 18:07                                 ` Linus Torvalds
2013-08-26 18:11                                   ` Andy Lutomirski
2013-08-27 19:16                                   ` [RFC PATCH] fs: Add user_file_or_path_at and use it for truncate Andy Lutomirski
2013-08-27 19:32                                     ` Linus Torvalds
2013-08-27 20:28                                       ` Andy Lutomirski
2013-08-28  6:16                                         ` Al Viro
2013-08-28 16:24                                           ` Linus Torvalds
2013-08-28 19:04                                           ` Andy Lutomirski
2013-08-28 19:59                                             ` Al Viro
2013-08-28 21:07                                               ` Andy Lutomirski
2013-08-27 23:08                                     ` Al Viro
2013-08-27 23:13                                       ` Andy Lutomirski
2013-08-24 18:29             ` /proc/pid/fd && anon_inode_fops Oleg Nesterov
2013-08-24 21:24               ` Willy Tarreau
2013-08-25  5:23                 ` Al Viro
2013-08-25  6:50                   ` Willy Tarreau
2013-08-25 18:51                     ` Linus Torvalds
2013-08-25 19:48                       ` Oleg Nesterov
2013-08-25 20:05                         ` Linus Torvalds
2013-08-26 15:33                           ` Oleg Nesterov
2013-08-26 16:37                             ` Oleg Nesterov
2013-08-26 17:54                               ` [PATCH] proc: make proc_fd_permission() thread-friendly Oleg Nesterov
2013-08-26 18:09                                 ` Linus Torvalds
2013-08-26 19:35                                   ` Linus Torvalds
2013-08-26 20:20                                     ` Willy Tarreau
2013-08-27 15:05                                       ` Oleg Nesterov
2013-08-27 14:39                                     ` [PATCH 0/1] proc: make /proc/self point to thread Oleg Nesterov
2013-08-27 14:40                                       ` [PATCH 1/1] " Oleg Nesterov
2013-08-27 16:39                                         ` Linus Torvalds
2013-08-27 17:49                                           ` Oleg Nesterov
2013-08-27 18:15                                             ` Linus Torvalds
2013-08-27 18:28                                               ` Oleg Nesterov
     [not found]                                     ` <CALCETrXP-mYBPRon=0NzexW1FK1Qxz2+Bwv7-WeHBQpvW7ywRg@mail.gmail.com>
2013-08-27 15:45                                       ` [PATCH] proc: make proc_fd_permission() thread-friendly Oleg Nesterov
2013-08-26 18:32                                 ` Eric W. Biederman
2013-08-26 18:46                                   ` Oleg Nesterov
2013-08-26 18:56                                     ` Oleg Nesterov
2013-08-26 19:10                                     ` Eric W. Biederman
2013-08-27 14:53                                       ` Oleg Nesterov
2013-08-25 18:32                   ` /proc/pid/fd && anon_inode_fops Linus Torvalds
2013-08-25 19:11                     ` Al Viro
2013-08-25 19:17                     ` Andy Lutomirski
2013-09-03 15:58                     ` Pavel Machek
2013-08-25 15:45                 ` Oleg Nesterov
2013-08-22 19:39       ` [PATCH v2] vfs: Tighten up linkat(..., AT_EMPTY_PATH) Willy Tarreau

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