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From: Mimi Zohar <zohar@linux.ibm.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: linux-integrity@vger.kernel.org, James Morris <jmorris@namei.org>,
	"Serge E . Hallyn" <serge@hallyn.com>,
	linux-security-module <linux-security-module@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Eric Biggers <ebiggers@kernel.org>,
	Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [RFC PATCH 2/2] integrity: double check iint_cache was initialized
Date: Wed, 24 Mar 2021 07:10:24 -0400	[thread overview]
Message-ID: <37aeaf361bfbd800e29db761f5160f2ce1869298.camel@linux.ibm.com> (raw)
In-Reply-To: <0a0c5cc5-0e1b-ef01-60c4-5247af2124f4@i-love.sakura.ne.jp>

On Wed, 2021-03-24 at 19:10 +0900, Tetsuo Handa wrote:
> On 2021/03/24 1:13, Mimi Zohar wrote:
> > On Wed, 2021-03-24 at 00:14 +0900, Tetsuo Handa wrote:
> >> On 2021/03/23 23:47, Mimi Zohar wrote:
> >>> Initially I also questioned making "integrity" an LSM.  Perhaps it's
> >>> time to reconsider.   For now, it makes sense to just fix the NULL
> >>> pointer dereferencing.
> >>
> >> Do we think calling panic() as "fix the NULL pointer dereferencing" ?
> > 
> > Not supplying "integrity" as an "lsm=" option is a user error.  There
> > are only two options - allow or deny the caller to proceed.   If the
> > user is expecting the integrity subsystem to be properly working,
> > returning a NULL and allowing the system to boot (RFC patch version)
> > does not make sense.   Better to fail early.
> 
> What does the "user" mean? Those who load the vmlinux?
> Only the "root" user (so called administrators)?
> Any users including other than "root" user?
> 
> If the user means those who load the vmlinux, that user is explicitly asking
> for disabling "integrity" for some reason. In that case, it is a bug if
> booting with "integrity" disabled is impossible.
> 
> If the user means something other than those who load the vmlinux,
> is there a possibility that that user (especially non "root" users) is
> allowed to try to use "integrity" ? If processes other than global init
> process can try to use "integrity", wouldn't it be a DoS attack vector?
> Please explain in the descripotion why calling panic() does not cause
> DoS attack vector.

User in this case, is anyone rebooting the system and is intentionally
changing the default values, dropping the "integrity" option on the
boot command line.

Mimi


  reply	other threads:[~2021-03-24 11:11 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-19 20:03 [RFC PATCH 1/2] ima: don't access a file's integrity status before an IMA policy is loaded Mimi Zohar
2021-03-19 20:03 ` [RFC PATCH 2/2] integrity: double check iint_cache was initialized Mimi Zohar
2021-03-22  7:10   ` Tetsuo Handa
2021-03-22  7:53     ` Dmitry Vyukov
2021-03-23  1:46       ` Tetsuo Handa
2021-03-23 12:09         ` Mimi Zohar
2021-03-23 13:37           ` Tetsuo Handa
2021-03-23 14:01             ` Tetsuo Handa
2021-03-23 14:47               ` Mimi Zohar
2021-03-23 15:14                 ` Tetsuo Handa
2021-03-23 16:13                   ` Mimi Zohar
2021-03-24 10:10                     ` Tetsuo Handa
2021-03-24 11:10                       ` Mimi Zohar [this message]
2021-03-24 11:20                         ` Tetsuo Handa
2021-03-24 11:37                           ` Dmitry Vyukov
2021-03-24 11:49                             ` Mimi Zohar
2021-03-24 11:58                               ` Dmitry Vyukov
2021-03-24 12:17                                 ` Mimi Zohar
2021-03-24 15:56                                 ` Casey Schaufler

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