From: Christian Brauner <brauner@kernel.org>
To: "Christian A. Ehrhardt" <lk@c--e.de>, Tejun Heo <tj@kernel.org>
Cc: Tejun Heo <tj@kernel.org>,
syzbot <syzbot+534ee3d24c37c411f37f@syzkaller.appspotmail.com>,
gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com,
Yosry Ahmed <yosryahmed@google.com>
Subject: Re: [PATCH] cgroup: Fix crash with CLONE_INTO_CGROUP and v1 cgroups
Date: Sun, 9 Oct 2022 19:35:19 +0200 [thread overview]
Message-ID: <20221009173519.jwuissylg5haicie@wittgenstein> (raw)
In-Reply-To: <Y0LITEA/22Z7YVSa@cae.in-ulm.de>
On Sun, Oct 09, 2022 at 03:10:36PM +0200, Christian A. Ehrhardt wrote:
>
> Since commit f3a2aebdd6, Version 1 cgroups no longer cause an
> error when used with CLONE_INTO_CGROUP. However, the permission
> checks performed during clone assume a Version 2 cgroup.
>
> Restore the error check for V1 cgroups in the clone() path.
>
> Reported-by: syzbot+534ee3d24c37c411f37f@syzkaller.appspotmail.com
> Link: https://lore.kernel.org/lkml/000000000000385cbf05ea3f1862@google.com/
> Fixes: f3a2aebdd6 ("cgroup: enable cgroup_get_from_file() on cgroup1")
> Signed-off-by: Christian A. Ehrhardt <lk@c--e.de>
> ---
Thanks for fixing this,
Reviewed-by: Christian Brauner (Microsoft) <brauner@kernel.org>
Fwiw, @Tejun, after
f3a2aebdd6 ("cgroup: enable cgroup_get_from_file() on cgroup1")
that non-me-Christian fixes with this patch cgroup_get_from_file() looks
a bit odd. It could use sm like:
From 0a8a5f7acbec0385ec16cd93a9cff2486fae0ecb Mon Sep 17 00:00:00 2001
From: Christian Brauner <brauner@kernel.org>
Date: Sun, 9 Oct 2022 19:33:21 +0200
Subject: [PATCH] cgroup: remove unneeded local variable
Since commit f3a2aebdd6 ("cgroup: enable cgroup_get_from_file() on cgroup1")
the assigment to @cgrp has become pointless.
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
---
kernel/cgroup/cgroup.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 8ad2c267ff47..550e7bd96b76 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -6160,14 +6160,12 @@ void cgroup_fork(struct task_struct *child)
static struct cgroup *cgroup_get_from_file(struct file *f)
{
struct cgroup_subsys_state *css;
- struct cgroup *cgrp;
css = css_tryget_online_from_dir(f->f_path.dentry, NULL);
if (IS_ERR(css))
return ERR_CAST(css);
- cgrp = css->cgroup;
- return cgrp;
+ return css->cgroup;
}
/**
--
2.34.1
next prev parent reply other threads:[~2022-10-09 17:37 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-05 0:59 [syzbot] general protection fault in kernfs_get_inode syzbot
2022-10-05 2:19 ` syzbot
2022-10-07 21:35 ` Tejun Heo
2022-10-08 5:46 ` Christian Brauner
2022-10-08 5:51 ` Christian Brauner
2022-10-08 11:15 ` syzbot
2022-10-08 18:29 ` Christian A. Ehrhardt
2022-10-09 8:42 ` Christian Brauner
2022-10-09 13:10 ` [PATCH] cgroup: Fix crash with CLONE_INTO_CGROUP and v1 cgroups Christian A. Ehrhardt
2022-10-09 17:35 ` Christian Brauner [this message]
2022-10-09 18:16 ` Greg KH
2022-10-10 18:48 ` Tejun Heo
2022-10-09 18:42 ` Yosry Ahmed
2022-10-10 18:38 ` Martin KaFai Lau
2022-10-10 18:43 ` Tejun Heo
2022-10-10 18:50 ` Yosry Ahmed
2022-10-10 19:51 ` Tejun Heo
2022-10-10 19:57 ` Yosry Ahmed
2022-10-10 20:07 ` Tejun Heo
2022-10-10 20:09 ` Yosry Ahmed
2022-11-17 7:26 ` [syzbot] general protection fault in kernfs_get_inode syzbot
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