From: Oleg Nesterov <oleg@redhat.com>
To: Paul Moore <paul@paul-moore.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>,
"chengjian (D)" <cj.chengjian@huawei.com>,
neilb@suse.com, Anna.Schumaker@netapp.com, keescook@chromium.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
viro@zeniv.linux.org.uk,
"Xiexiuqi (Xie XiuQi)" <xiexiuqi@huawei.com>,
Li Bin <huawei.libin@huawei.com>,
yanaijie@huawei.com, peterz@infradead.org, mingo@redhat.com,
Linux Security Module list
<linux-security-module@vger.kernel.org>,
selinux@vger.kernel.org
Subject: Re: kernel BUG at kernel/cred.c:434!
Date: Mon, 15 Apr 2019 17:05:21 +0200 [thread overview]
Message-ID: <20190415150520.GA13257@redhat.com> (raw)
In-Reply-To: <CAHC9VhQ7ihqU0K57ctwzoHq0t0QVJPKiQQZn5TXB1FUqsvOSEQ@mail.gmail.com>
On 04/15, Paul Moore wrote:
>
> On Mon, Apr 15, 2019 at 9:43 AM Oleg Nesterov <oleg@redhat.com> wrote:
> > Well, acct("/proc/self/attr/current") doesn't look like a good idea, but I do
> > not know where should we put the additional check... And probably
> > "echo /proc/self/attr/current > /proc/sys/kernel/core_pattern" can hit the
> > same problem, do_coredump() does override_creds() too.
> >
> > May be just add
> >
> > if (current->cred != current->real_cred)
> > return -EACCES;
> >
> > into proc_pid_attr_write(), I dunno.
>
> Is the problem that do_acct_process() is calling override_creds() and
> the returned/old credentials are being freed before do_acct_process()
> can reinstall the creds via revert_creds()? Presumably because the
> process accounting is causing the credentials to be replaced?
Afaics, the problem is that do_acct_process() does override_creds() and
then __kernel_write(). Which calls proc_pid_attr_write(), which in turn calls
selinux_setprocattr(), which does another prepare_creds() + commit_creds();
and commit_creds() hits
BUG_ON(task->cred != old);
Oleg.
next prev parent reply other threads:[~2019-04-15 15:05 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <6e4428ca-3da1-a033-08f7-a51e57503989@huawei.com>
2019-04-12 15:28 ` kernel BUG at kernel/cred.c:434! Casey Schaufler
2019-04-15 13:43 ` Oleg Nesterov
2019-04-15 14:48 ` Paul Moore
2019-04-15 15:05 ` Oleg Nesterov [this message]
2019-04-15 16:20 ` Paul Moore
2019-04-16 3:40 ` Kees Cook
2019-04-16 14:46 ` chengjian (D)
2019-04-17 14:30 ` Paul Moore
2019-04-17 14:57 ` Oleg Nesterov
2019-04-17 15:39 ` Casey Schaufler
2019-04-17 15:40 ` Paul Moore
2019-04-17 16:27 ` Oleg Nesterov
2019-04-17 16:42 ` Casey Schaufler
2019-04-18 13:39 ` Stephen Smalley
2019-04-17 23:39 ` Paul Moore
2019-04-18 0:17 ` John Johansen
2019-04-18 0:24 ` Casey Schaufler
2019-04-18 2:49 ` Yang Yingliang
2019-04-19 2:04 ` Paul Moore
2019-04-19 2:34 ` Yang Yingliang
2019-04-19 13:24 ` Paul Moore
2019-04-19 14:34 ` Yang Yingliang
2019-04-19 16:13 ` Paul Moore
2019-04-20 7:38 ` Yang Yingliang
2019-04-22 19:48 ` Paul Moore
2019-04-23 4:08 ` Yang Yingliang
2019-04-23 20:18 ` Paul Moore
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