From: "Serge E. Hallyn" <serge@hallyn.com>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
Micah Morton <mortonm@chromium.org>,
jmorris@namei.org, Kees Cook <keescook@chromium.org>,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH] LSM: add SafeSetID module that gates setid calls
Date: Fri, 2 Nov 2018 19:22:27 +0000 [thread overview]
Message-ID: <20181102192227.GA21498@mail.hallyn.com> (raw)
In-Reply-To: <b1f95526-d0f1-712e-e0a7-9710cae7e1f0@schaufler-ca.com>
Quoting Casey Schaufler (casey@schaufler-ca.com):
> On 11/2/2018 11:30 AM, Serge E. Hallyn wrote:
> > Quoting Casey Schaufler (casey@schaufler-ca.com):
> >
> >> Let me suggest a change to the way your LSM works
> >> that would reduce my concerns. Rather than refusing to
> >> make a UID change that isn't on your whitelist, kill a
> >> process that makes a prohibited request. This mitigates
> >> the problem where a process doesn't check for an error
> >> return. Sure, your system will be harder to get running
> >> until your whitelist is complete, but you'll avoid a
> >> whole category of security bugs.
> > Might also consider not restricting CAP_SETUID, but instead adding a
> > new CAP_SETUID_RANGE capability. That way you can be sure there will be
> > no regressions with any programs which run with CAP_SETUID.
> >
> > Though that violates what Casey was just arguing halfway up the email.
>
> I know that it's hard to believe 20 years after the fact,
> but the POSIX group worked very hard to ensure that the granularity
> of capabilities was correct for the security policy that the
> interfaces defined in P1003.1. What would CAP_SETUID_RANGE mean?
CAP_SETUID would mean you can switch to any uid.
CAP_SETUID_RANGE would mean you could make the transitions which have
been defined through <handwave> some mechanism. Be it prctl, or some
new security.uidrange xattr, or the mechanism Micah proposed, except
it only applies for CAP_SETUID_RANGE not CAP_SETUID.
-serge
next prev parent reply other threads:[~2018-11-02 19:22 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-31 15:28 [PATCH] LSM: add SafeSetID module that gates setid calls mortonm
2018-10-31 21:02 ` Serge E. Hallyn
2018-10-31 21:57 ` Kees Cook
2018-10-31 22:37 ` Casey Schaufler
2018-11-01 1:12 ` Micah Morton
2018-11-01 6:13 ` Serge E. Hallyn
2018-11-01 15:39 ` Casey Schaufler
2018-11-01 15:56 ` Serge E. Hallyn
2018-11-01 16:18 ` Micah Morton
2018-11-01 6:07 ` Serge E. Hallyn
2018-11-01 16:11 ` Micah Morton
2018-11-01 16:22 ` Micah Morton
2018-11-01 16:41 ` Micah Morton
2018-11-01 17:08 ` Casey Schaufler
2018-11-01 19:52 ` Micah Morton
2018-11-02 16:05 ` Casey Schaufler
2018-11-02 17:12 ` Micah Morton
2018-11-02 18:19 ` Casey Schaufler
2018-11-02 18:30 ` Serge E. Hallyn
2018-11-02 19:02 ` Casey Schaufler
2018-11-02 19:22 ` Serge E. Hallyn [this message]
2018-11-08 20:53 ` Micah Morton
2018-11-08 21:34 ` Casey Schaufler
2018-11-09 0:30 ` Micah Morton
2018-11-09 23:21 ` [PATCH] LSM: generalize flag passing to security_capable mortonm
2018-11-21 16:54 ` [PATCH] LSM: add SafeSetID module that gates setid calls mortonm
2018-12-06 0:08 ` Kees Cook
2018-12-06 17:51 ` Micah Morton
2019-01-11 17:13 ` [PATCH v2] " mortonm
2019-01-15 0:38 ` Kees Cook
2019-01-15 18:04 ` [PATCH v3 1/2] LSM: mark all set*uid call sites in kernel/sys.c mortonm
2019-01-15 19:34 ` Kees Cook
2019-01-15 18:04 ` [PATCH v3 2/2] LSM: add SafeSetID module that gates setid calls mortonm
2019-01-15 19:44 ` Kees Cook
2019-01-15 21:50 ` [PATCH v4 " mortonm
2019-01-15 22:32 ` Kees Cook
2019-01-16 15:46 ` [PATCH v5 " mortonm
2019-01-16 16:10 ` Casey Schaufler
2019-01-22 20:40 ` Micah Morton
2019-01-22 22:28 ` James Morris
2019-01-22 22:40 ` Micah Morton
2019-01-22 22:42 ` [PATCH v3 1/2] " mortonm
2019-01-25 15:51 ` Micah Morton
2019-01-25 20:15 ` [PATCH v5 2/2] " James Morris
2019-01-25 21:06 ` Micah Morton
2019-01-28 19:47 ` Micah Morton
2019-01-28 19:56 ` Kees Cook
2019-01-28 20:09 ` James Morris
2019-01-28 20:19 ` Micah Morton
2019-01-28 20:30 ` [PATCH] LSM: Add 'name' field for SafeSetID in DEFINE_LSM mortonm
2019-01-28 22:12 ` James Morris
2019-01-28 22:33 ` [PATCH v5 2/2] LSM: add SafeSetID module that gates setid calls Micah Morton
2019-01-29 17:25 ` James Morris
2019-01-29 21:14 ` Micah Morton
2019-01-30 7:15 ` Kees Cook
2019-02-06 19:03 ` [PATCH] LSM: SafeSetID: add selftest mortonm
2019-02-06 19:26 ` Edwin Zimmerman
2019-02-07 21:54 ` Micah Morton
2019-02-12 19:01 ` James Morris
2019-01-15 21:58 ` [PATCH v3 2/2] LSM: add SafeSetID module that gates setid calls Micah Morton
2019-01-15 19:49 ` [PATCH v2] " Micah Morton
2019-01-15 19:53 ` Kees Cook
2019-01-15 4:07 ` James Morris
2019-01-15 19:42 ` Micah Morton
2018-11-02 19:28 ` [PATCH] " Micah Morton
2018-11-06 19:09 ` [PATCH v2] " mortonm
2018-11-06 20:59 ` [PATCH] " James Morris
2018-11-06 21:21 ` [PATCH v3] " mortonm
2018-11-02 18:07 ` [PATCH] " Stephen Smalley
2018-11-02 19:13 ` Micah Morton
2018-11-19 18:54 ` [PATCH] [PATCH] LSM: generalize flag passing to security_capable mortonm
2018-12-13 22:29 ` Micah Morton
2018-12-13 23:09 ` Casey Schaufler
2018-12-14 0:05 ` Micah Morton
2018-12-18 22:37 ` [PATCH v2] " mortonm
2019-01-07 17:55 ` Micah Morton
2019-01-07 18:16 ` Casey Schaufler
2019-01-07 18:36 ` Micah Morton
2019-01-07 18:46 ` Casey Schaufler
2019-01-07 19:02 ` Micah Morton
2019-01-07 22:57 ` [PATCH v3] " mortonm
2019-01-07 23:13 ` [PATCH v2] " Kees Cook
2019-01-08 0:10 ` [PATCH v4] " mortonm
2019-01-08 0:20 ` Kees Cook
2019-01-09 18:39 ` Micah Morton
2019-01-10 22:31 ` James Morris
2019-01-10 23:03 ` Micah Morton
2019-01-08 0:10 ` [PATCH v2] " Micah Morton
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