From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Vasiliy Kulikov <segoon@openwall.com>
Cc: Pavel Machek <pavel@ucw.cz>, Andrew Morton <akpm00@gmail.com>,
linux-kernel@vger.kernel.org, containers@lists.osdl.org,
linux-fsdevel@vger.kernel.org,
Kirill Shutemov <kirill@shutemov.name>,
Pavel Emelyanov <xemul@parallels.com>,
James Bottomley <jbottomley@parallels.com>,
Nathan Lynch <ntl@pobox.com>, Zan Lynx <zlynx@acm.org>,
Daniel Lezcano <dlezcano@fr.ibm.com>, Tejun Heo <tj@kernel.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Al Viro <viro@ZenIV.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [patch 2/2] fs, proc: Introduce the /proc/<pid>/map_files/ directory v12
Date: Wed, 14 Sep 2011 20:00:19 +0400 [thread overview]
Message-ID: <20110914160018.GW25367@sun> (raw)
In-Reply-To: <20110914144841.GA7906@albatros>
On Wed, Sep 14, 2011 at 06:48:41PM +0400, Vasiliy Kulikov wrote:
...
>
> Actually now I see the difference between having something mapped and
> having an _fd_ of this something.
>
> Relevant code:
>
> +static struct dentry *
> +proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
> + struct task_struct *task, const void *ptr)
> +{
> ...
> + inode->i_mode = S_IFLNK;
> +
> + if (file->f_mode & FMODE_READ)
> + inode->i_mode |= S_IRUSR | S_IXUSR;
> + if (file->f_mode & FMODE_WRITE)
> + inode->i_mode |= S_IWUSR | S_IXUSR;
>
>
> If you have a write mmap area, but no fd, you may not trunc a file; with
> map_files/ you may get an fd and ftrunc it.
>
This stands for anonymous memory, and if you have enough rights to
access the task this ftruncate is the last problem (since having ptrace
access to the task I _aready_ can trash various stuff inside, i dont need
even bother to look into map_files/ or whatever). So I don't see how
ftruncate migh harm you here?
Cyrill
next prev parent reply other threads:[~2011-09-14 16:00 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-13 21:13 [patch 0/2] symlinks for mapped files in proc Cyrill Gorcunov
2011-09-13 21:14 ` [patch 1/2] fs, proc: Make proc_get_link to use dentry instead of inode Cyrill Gorcunov
2011-09-14 1:37 ` Kirill A. Shutemov
2011-09-13 21:14 ` [patch 2/2] fs, proc: Introduce the /proc/<pid>/map_files/ directory v12 Cyrill Gorcunov
[not found] ` <20110914023428.GA4034@shutemov.name>
2011-09-14 5:54 ` Cyrill Gorcunov
2011-09-14 6:52 ` Andrew Morton
2011-09-14 10:56 ` Cyrill Gorcunov
2011-09-14 11:14 ` Pavel Machek
2011-09-14 11:39 ` Cyrill Gorcunov
2011-09-14 13:44 ` Cyrill Gorcunov
2011-09-14 14:48 ` Vasiliy Kulikov
2011-09-14 14:57 ` Vasiliy Kulikov
2011-09-14 16:00 ` Cyrill Gorcunov [this message]
2011-09-14 16:07 ` Vasiliy Kulikov
2011-09-14 16:13 ` Pavel Emelyanov
2011-09-14 16:21 ` Vasiliy Kulikov
2011-09-15 9:14 ` Cyrill Gorcunov
2011-09-15 9:27 ` Vasiliy Kulikov
2011-09-15 10:29 ` Cyrill Gorcunov
2011-09-15 10:56 ` Vasiliy Kulikov
2011-09-15 11:00 ` Cyrill Gorcunov
2011-09-15 20:19 ` Cyrill Gorcunov
2011-09-16 17:56 ` Vasiliy Kulikov
2011-09-16 18:07 ` Cyrill Gorcunov
2011-09-16 18:11 ` Vasiliy Kulikov
2011-09-16 18:26 ` Cyrill Gorcunov
2011-09-16 18:31 ` Kirill A. Shutemov
2011-09-16 18:40 ` Cyrill Gorcunov
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