From: Rafael Aquini <aquini@redhat.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: Tso Ted <tytso@mit.edu>, Adrian Bunk <bunk@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Laura Abbott <labbott@redhat.com>, Jeff Mahoney <jeffm@suse.com>,
Jiri Kosina <jikos@kernel.org>, Jessica Yu <jeyu@suse.de>,
Takashi Iwai <tiwai@suse.de>, Ann Davis <AnDavis@suse.com>,
Richard Palethorpe <rpalethorpe@suse.de>,
linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org,
kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org,
dyoung@redhat.com, bhe@redhat.com, corbet@lwn.net,
keescook@chromium.org, akpm@linux-foundation.org, cai@lca.pw,
rdunlap@infradead.org
Subject: Re: [PATCH v2] kernel: add panic_on_taint
Date: Fri, 8 May 2020 08:47:19 -0400 [thread overview]
Message-ID: <20200508124719.GB367616@optiplex-lnx> (raw)
In-Reply-To: <20200507222558.GA11244@42.do-not-panic.com>
On Thu, May 07, 2020 at 10:25:58PM +0000, Luis Chamberlain wrote:
> On Thu, May 07, 2020 at 06:06:06PM -0400, Rafael Aquini wrote:
> > On Thu, May 07, 2020 at 08:33:40PM +0000, Luis Chamberlain wrote:
> > > I *think* that a cmdline route to enable this would likely remove the
> > > need for the kernel config for this. But even with Vlastimil's work
> > > merged, I think we'd want yet-another value to enable / disable this
> > > feature. Do we need yet-another-taint flag to tell us that this feature
> > > was enabled?
> > >
> >
> > I guess it makes sense to get rid of the sysctl interface for
> > proc_on_taint, and only keep it as a cmdline option.
>
> That would be easier to support and k3eps this simple.
>
> > But the real issue seems to be, regardless we go with a cmdline-only option
> > or not, the ability of proc_taint() to set any arbitrary taint flag
> > other than just marking the kernel with TAINT_USER.
>
> I think we would have no other option but to add a new TAINT flag so
> that we know that the taint flag was modified by a user. Perhaps just
> re-using TAINT_USER when proc_taint() would suffice.
>
We might not need an extra taint flag if, perhaps, we could make these
two features mutually exclusive. The idea here is that bitmasks added
via panic_on_taint get filtered out in proc_taint(), so a malicious
user couldn't exploit the latter interface to easily panic the system,
when the first one is also in use.
-- Rafael
WARNING: multiple messages have this Message-ID (diff)
From: Rafael Aquini <aquini@redhat.com>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: linux-doc@vger.kernel.org, Takashi Iwai <tiwai@suse.de>,
Jeff Mahoney <jeffm@suse.com>,
bhe@redhat.com, corbet@lwn.net, Laura Abbott <labbott@redhat.com>,
dyoung@redhat.com, Ann Davis <AnDavis@suse.com>,
Richard Palethorpe <rpalethorpe@suse.de>,
keescook@chromium.org, Jiri Kosina <jikos@kernel.org>,
cai@lca.pw, Adrian Bunk <bunk@kernel.org>,
Tso Ted <tytso@mit.edu>, Jessica Yu <jeyu@suse.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
rdunlap@infradead.org, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
akpm@linux-foundation.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH v2] kernel: add panic_on_taint
Date: Fri, 8 May 2020 08:47:19 -0400 [thread overview]
Message-ID: <20200508124719.GB367616@optiplex-lnx> (raw)
In-Reply-To: <20200507222558.GA11244@42.do-not-panic.com>
On Thu, May 07, 2020 at 10:25:58PM +0000, Luis Chamberlain wrote:
> On Thu, May 07, 2020 at 06:06:06PM -0400, Rafael Aquini wrote:
> > On Thu, May 07, 2020 at 08:33:40PM +0000, Luis Chamberlain wrote:
> > > I *think* that a cmdline route to enable this would likely remove the
> > > need for the kernel config for this. But even with Vlastimil's work
> > > merged, I think we'd want yet-another value to enable / disable this
> > > feature. Do we need yet-another-taint flag to tell us that this feature
> > > was enabled?
> > >
> >
> > I guess it makes sense to get rid of the sysctl interface for
> > proc_on_taint, and only keep it as a cmdline option.
>
> That would be easier to support and k3eps this simple.
>
> > But the real issue seems to be, regardless we go with a cmdline-only option
> > or not, the ability of proc_taint() to set any arbitrary taint flag
> > other than just marking the kernel with TAINT_USER.
>
> I think we would have no other option but to add a new TAINT flag so
> that we know that the taint flag was modified by a user. Perhaps just
> re-using TAINT_USER when proc_taint() would suffice.
>
We might not need an extra taint flag if, perhaps, we could make these
two features mutually exclusive. The idea here is that bitmasks added
via panic_on_taint get filtered out in proc_taint(), so a malicious
user couldn't exploit the latter interface to easily panic the system,
when the first one is also in use.
-- Rafael
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next prev parent reply other threads:[~2020-05-08 13:13 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 18:06 [PATCH v2] kernel: add panic_on_taint Rafael Aquini
2020-05-07 18:06 ` Rafael Aquini
2020-05-07 18:22 ` Luis Chamberlain
2020-05-07 18:22 ` Luis Chamberlain
2020-05-07 18:43 ` Rafael Aquini
2020-05-07 18:43 ` Rafael Aquini
2020-05-07 18:47 ` Rafael Aquini
2020-05-07 18:47 ` Rafael Aquini
2020-05-07 20:33 ` Luis Chamberlain
2020-05-07 20:33 ` Luis Chamberlain
2020-05-07 22:06 ` Rafael Aquini
2020-05-07 22:06 ` Rafael Aquini
2020-05-07 22:25 ` Luis Chamberlain
2020-05-07 22:25 ` Luis Chamberlain
2020-05-08 12:47 ` Rafael Aquini [this message]
2020-05-08 12:47 ` Rafael Aquini
2020-05-09 3:48 ` Luis Chamberlain
2020-05-09 3:48 ` Luis Chamberlain
2020-05-09 14:56 ` Rafael Aquini
2020-05-09 14:56 ` Rafael Aquini
2020-05-07 18:50 ` Luis Chamberlain
2020-05-07 18:50 ` Luis Chamberlain
2020-05-07 18:53 ` Rafael Aquini
2020-05-07 18:53 ` Rafael Aquini
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