From: James Bottomley <jejb@linux.ibm.com>
To: Stefan Berger <stefanb@linux.ibm.com>, linux-integrity@vger.kernel.org
Cc: zohar@linux.ibm.com, serge@hallyn.com,
christian.brauner@ubuntu.com, containers@lists.linux.dev,
dmitry.kasatkin@gmail.com, ebiederm@xmission.com,
krzysztof.struczynski@huawei.com, roberto.sassu@huawei.com,
mpeters@redhat.com, lhinds@redhat.com, lsturman@redhat.com,
puiterwi@redhat.com, jamjoom@us.ibm.com,
linux-kernel@vger.kernel.org, paul@paul-moore.com,
rgb@redhat.com, linux-security-module@vger.kernel.org,
jmorris@namei.org, Denis Semakin <denis.semakin@huawei.com>
Subject: Re: [RFC 17/20] ima: Use integrity_admin_ns_capable() to check corresponding capability
Date: Wed, 01 Dec 2021 11:58:09 -0500 [thread overview]
Message-ID: <7c751783b28766412f158e5ca074748ed18070bd.camel@linux.ibm.com> (raw)
In-Reply-To: <20211130160654.1418231-18-stefanb@linux.ibm.com>
On Tue, 2021-11-30 at 11:06 -0500, Stefan Berger wrote:
> From: Denis Semakin <denis.semakin@huawei.com>
>
> Use integrity_admin_ns_capable() to check corresponding capability to
> allow read/write IMA policy without CAP_SYS_ADMIN but with
> CAP_INTEGRITY_ADMIN.
>
> Signed-off-by: Denis Semakin <denis.semakin@huawei.com>
> ---
> security/integrity/ima/ima_fs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/integrity/ima/ima_fs.c
> b/security/integrity/ima/ima_fs.c
> index fd2798f2d224..6766bb8262f2 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -393,7 +393,7 @@ static int ima_open_policy(struct inode *inode,
> struct file *filp)
> #else
> if ((filp->f_flags & O_ACCMODE) != O_RDONLY)
> return -EACCES;
> - if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN))
> + if (!integrity_admin_ns_capable(ns->user_ns))
so this one is basically replacing what you did in RFC 16/20, which
seems a little redundant.
The question I'd like to ask is: is there still a reason for needing
CAP_INTEGRITY_ADMIN? My thinking is that now IMA is pretty much tied
to requiring a user (and a mount, because of securityfs_ns) namespace,
there might not be a pressing need for an admin capability separated
from CAP_SYS_ADMIN because the owner of the user namespace passes the
ns_capable(..., CAP_SYS_ADMIN) check. The rationale in
https://kernsec.org/wiki/index.php/IMA_Namespacing_design_considerations
Is effectively "because CAP_SYS_ADMIN is too powerful" but that's no
longer true of the user namespace owner. It only passes the ns_capable
() check not the capable() one, so while it does get CAP_SYS_ADMIN, it
can only use it in a few situations which represent quite a power
reduction already.
James
next prev parent reply other threads:[~2021-12-01 16:58 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-30 16:06 [RFC 00/20] ima: Namespace IMA with audit support in IMA-ns Stefan Berger
2021-11-30 16:06 ` [RFC 01/20] ima: Add IMA namespace support Stefan Berger
2021-11-30 16:06 ` [RFC 02/20] ima: Define ns_status for storing namespaced iint data Stefan Berger
2021-11-30 16:06 ` [RFC 03/20] ima: Namespace audit status flags Stefan Berger
2021-11-30 16:06 ` [RFC 04/20] ima: Move delayed work queue and variables into ima_namespace Stefan Berger
2021-11-30 16:06 ` [RFC 05/20] ima: Move IMA's keys queue related " Stefan Berger
2021-11-30 16:06 ` [RFC 06/20] ima: Move policy " Stefan Berger
2021-11-30 16:06 ` [RFC 07/20] ima: Move ima_htable " Stefan Berger
2021-11-30 16:06 ` [RFC 08/20] ima: Move measurement list related variables " Stefan Berger
2021-12-02 12:46 ` James Bottomley
2021-12-02 13:41 ` Stefan Berger
2021-12-02 16:29 ` James Bottomley
2021-12-02 16:45 ` Stefan Berger
2021-12-02 17:44 ` James Bottomley
2021-12-02 18:03 ` Stefan Berger
2021-12-02 20:03 ` James Bottomley
2021-11-30 16:06 ` [RFC 09/20] ima: Only accept AUDIT rules for IMA non-init_ima_ns namespaces for now Stefan Berger
2021-11-30 16:06 ` [RFC 10/20] ima: Implement hierarchical processing of file accesses Stefan Berger
2021-11-30 16:06 ` [RFC 11/20] securityfs: Prefix global variables with securityfs_ Stefan Berger
2021-11-30 16:06 ` [RFC 12/20] securityfs: Pass static variables as parameters from top level functions Stefan Berger
2021-11-30 16:06 ` [RFC 13/20] securityfs: Build securityfs_ns for namespacing support Stefan Berger
2021-12-02 13:35 ` Christian Brauner
2021-12-02 13:47 ` Stefan Berger
2021-11-30 16:06 ` [RFC 14/20] ima: Move some IMA policy and filesystem related variables into ima_namespace Stefan Berger
2021-11-30 16:06 ` [RFC 15/20] capabilities: Introduce CAP_INTEGRITY_ADMIN Stefan Berger
2021-11-30 17:27 ` Casey Schaufler
2021-11-30 17:41 ` Stefan Berger
2021-11-30 17:50 ` Casey Schaufler
2021-11-30 16:06 ` [RFC 16/20] ima: Use ns_capable() for namespace policy access Stefan Berger
2021-11-30 16:06 ` [RFC 17/20] ima: Use integrity_admin_ns_capable() to check corresponding capability Stefan Berger
2021-12-01 16:58 ` James Bottomley [this message]
2021-12-01 17:35 ` Stefan Berger
2021-12-01 19:29 ` James Bottomley
2021-12-02 7:16 ` Denis Semakin
2021-12-02 12:33 ` James Bottomley
2021-12-02 17:54 ` Stefan Berger
2021-12-02 12:59 ` Christian Brauner
2021-12-02 13:01 ` Christian Brauner
2021-12-02 15:58 ` Casey Schaufler
2021-11-30 16:06 ` [RFC 18/20] userns: Introduce a refcount variable for calling early teardown function Stefan Berger
2021-11-30 16:06 ` [RFC 19/20] ima/userns: Define early teardown function for IMA namespace Stefan Berger
2021-11-30 16:06 ` [RFC 20/20] ima: Setup securityfs_ns " Stefan Berger
2021-12-01 17:56 ` James Bottomley
2021-12-01 18:11 ` Stefan Berger
2021-12-01 19:21 ` James Bottomley
2021-12-01 20:25 ` Stefan Berger
2021-12-01 21:11 ` James Bottomley
2021-12-01 21:34 ` Stefan Berger
2021-12-01 22:01 ` James Bottomley
2021-12-01 22:09 ` Stefan Berger
2021-12-01 22:19 ` James Bottomley
2021-12-02 0:02 ` Stefan Berger
2021-12-02 13:18 ` Christian Brauner
2021-12-02 13:52 ` Stefan Berger
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