From: Al Viro <viro@ZenIV.linux.org.uk>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Matt Helsley <matthltc@us.ibm.com>,
xemul@parallels.com, containers@lists.linux-foundation.org,
linux-kernel@vger.kernel.org, dave@linux.vnet.ibm.com,
mingo@elte.hu, torvalds@linux-foundation.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 1/9] exec_path 1/9: introduce ->exec_path and switch /proc/*/exe
Date: Sat, 6 Jun 2009 08:22:44 +0100 [thread overview]
Message-ID: <20090606072244.GA13497@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20090603230422.GB853@x200.localdomain>
On Thu, Jun 04, 2009 at 03:04:22AM +0400, Alexey Dobriyan wrote:
> diff --git a/fs/binfmt_som.c b/fs/binfmt_som.c
> index eff74b9..6c56262 100644
> --- a/fs/binfmt_som.c
> +++ b/fs/binfmt_som.c
> @@ -174,6 +174,7 @@ static int map_som_binary(struct file *file,
> up_write(¤t->mm->mmap_sem);
> if (retval > 0 || retval < -1024)
> retval = 0;
> + set_task_exec_path(current, &bprm->file->f_path);
Oh? Even on failure exits?
> + if (!path->mnt || !path->dentry)
> + return -ENOENT;
Umm... I really don't like that. Note that path with NULL vfsmount
and non-NULL dentry should never happen. If anything, we ought
to add path_empty(path) (!(path)->mnt) and convert such places to it.
> +static inline void set_task_exec_path(struct task_struct *tsk, struct path *path)
> +{
> + struct path old_path;
> +
> + path_get(path);
> + task_lock(tsk);
> + old_path = tsk->exec_path;
> + tsk->exec_path = *path;
> + task_unlock(tsk);
> + path_put(&old_path);
> +}
Do we ever have a right to do that to anything other than current? Note
that fork() is a special case anyway...
> + set_task_exec_path(tsk, &(struct path){ .mnt = NULL, .dentry = NULL });
Ew...
> + get_task_exec_path(current, &p->exec_path);
> +
We already have that value sitting there, so why not get_path(&p->exec_path)?
The real problem I have with that we *really* can't umount the filesystem
that used to host the binary anymore. At all.
Frankly, I'm almost tempted to add explicit way to switch the damn thing
via /proc/self/something - e.g. allow a binary to write a pathname to
/proc/self/set_exec and have that switch the sucker. The interesting
part, of course, is figuring out the security implications of that...
next prev parent reply other threads:[~2009-06-06 7:22 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20090526113618.GJ28083@us.ibm.com>
[not found] ` <20090526162415.fb9cefef.akpm@linux-foundation.org>
[not found] ` <20090531215427.GA29534@x200.localdomain>
[not found] ` <20090531151953.8f8b14b5.akpm@linux-foundation.org>
[not found] ` <20090531151953.8f8b14b5.akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
2009-06-03 23:04 ` [PATCH 1/9] exec_path 1/9: introduce ->exec_path and switch /proc/*/exe Alexey Dobriyan
2009-06-03 23:05 ` [PATCH 2/9] exec_path 2/9: switch audit to ->exec_path Alexey Dobriyan
[not found] ` <20090603230422.GB853-2ev+ksY9ol182hYKe6nXyg@public.gmane.org>
2009-06-03 23:05 ` [PATCH 3/9] exec_path 3/9: switch TOMOYO " Alexey Dobriyan
2009-06-03 23:06 ` [PATCH 4/9] exec_path 4/9: switch oprofile " Alexey Dobriyan
2009-06-03 23:06 ` [PATCH 6/9] exec_path 6/9: add struct spu::tsk Alexey Dobriyan
2009-06-03 23:06 ` [PATCH 5/9] exec_path 5/9: make struct spu_context::owner task_struct Alexey Dobriyan
2009-06-03 23:07 ` [PATCH 7/9] exec_path 7/9: switch cell SPU thing to ->exec_path Alexey Dobriyan
2009-06-03 23:07 ` [PATCH 8/9] exec_path 8/9: remove ->exe_file et al Alexey Dobriyan
2009-06-03 23:08 ` [PATCH 9/9] exec_path 9/9: remove VM_EXECUTABLE Alexey Dobriyan
2009-06-04 7:24 ` Matt Helsley
2009-06-03 23:36 ` [PATCH 1/9] exec_path 1/9: introduce ->exec_path and switch /proc/*/exe Linus Torvalds
2009-06-04 7:55 ` Matt Helsley
2009-06-04 8:10 ` Matt Helsley
2009-06-04 15:07 ` Linus Torvalds
2009-06-04 21:30 ` Matt Helsley
2009-06-04 22:42 ` Alexey Dobriyan
2009-06-05 3:49 ` Matt Helsley
2009-06-05 10:45 ` Christoph Hellwig
2009-06-05 15:10 ` Linus Torvalds
2009-06-05 15:41 ` Alexey Dobriyan
2009-06-05 15:49 ` Linus Torvalds
2009-06-05 16:09 ` Alexey Dobriyan
[not found] ` <20090605160943.GA5262-2ev+ksY9ol182hYKe6nXyg@public.gmane.org>
2009-06-05 16:48 ` Linus Torvalds
2009-06-05 17:46 ` Alexey Dobriyan
2009-06-06 7:22 ` Al Viro [this message]
2009-06-15 22:10 ` Alexey Dobriyan
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