From: Steven Rostedt <rostedt@goodmis.org>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
Linux Trace Kernel <linux-trace-kernel@vger.kernel.org>,
Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [PATCH] eventfs: Stop using dcache_readdir() for getdents()
Date: Wed, 3 Jan 2024 13:51:02 -0500 [thread overview]
Message-ID: <20240103135102.38352956@gandalf.local.home> (raw)
In-Reply-To: <CAHk-=wjVdGkjDXBbvLn2wbZnqP4UsH46E3gqJ9m7UG6DpX2+WA@mail.gmail.com>
On Wed, 3 Jan 2024 10:38:09 -0800
Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Wed, 3 Jan 2024 at 10:12, Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > Much better. Now eventfs looks more like a real filesystem, and less
> > like an eldritch horror monster that is parts of dcache tackled onto a
> > pseudo-filesystem.
>
> Oh, except I think you still need to just remove the 'set_gid()' mess.
>
> It's disgusting and it's wrong, and it's not even what the 'uid'
> option does (it only sets the root inode uid).
>
> If you remount the filesystem with different gid values, you get to
> keep both broken pieces. And if it isn't a remount, then setting the
> root uid is sufficient.
>
> I think the whole thing was triggered by commit 49d67e445742, and
> maybe the fix is to just revert that commit.
>
> That commit makes no sense in general, since the default mounting
> position for tracefs that the kernel sets up is only accessible to
> root anyway.
>
> Alternatively, just do the ->permissions() thing, and allow access to
> the group in the mount options.
>
> Getting rid of set_gid() would be this attached lovely patch:
>
> fs/tracefs/inode.c | 83 ++----------------------------------------------------
> 1 file changed, 2 insertions(+), 81 deletions(-)
>
> and would get rid of the final (?) piece of disgusting dcache hackery
> that tracefs most definitely should not have.
>
I'll look at that and play with it. I understand VFS much better now that I
spent so much time with eventfs. That commit had to do with allowing OTH
read access, which is a security issue as the trace files expose a lot of
the kernel internals.
I think these changes are a bit much for -rc8, don't you? Or do you want
all this in before v6.7 is released. I'd be more comfortable with adding
these changes in the upcoming merge window, where I can have more time
playing with them.
-- Steve
next prev parent reply other threads:[~2024-01-03 18:49 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-03 15:25 [PATCH] eventfs: Stop using dcache_readdir() for getdents() Steven Rostedt
2024-01-03 18:12 ` Linus Torvalds
2024-01-03 18:27 ` Steven Rostedt
2024-01-03 18:38 ` Linus Torvalds
2024-01-03 18:51 ` Steven Rostedt [this message]
2024-01-03 19:04 ` Linus Torvalds
2024-01-03 19:53 ` Steven Rostedt
2024-01-03 19:57 ` Linus Torvalds
2024-01-03 21:54 ` Linus Torvalds
2024-01-03 22:05 ` Steven Rostedt
2024-01-03 22:14 ` Linus Torvalds
2024-01-03 22:06 ` Linus Torvalds
2024-01-03 22:14 ` Al Viro
2024-01-03 22:17 ` Linus Torvalds
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