From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huaweicloud.com>,
mark@fasheh.com, jlbec@evilplan.org, joseph.qi@linux.alibaba.com,
dmitry.kasatkin@gmail.com, paul@paul-moore.com,
jmorris@namei.org, serge@hallyn.com,
stephen.smalley.work@gmail.com, eparis@parisplace.org,
casey@schaufler-ca.com
Cc: ocfs2-devel@oss.oracle.com, reiserfs-devel@vger.kernel.org,
linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org, selinux@vger.kernel.org,
linux-kernel@vger.kernel.org, keescook@chromium.org,
nicolas.bouchinet@clip-os.org,
Roberto Sassu <roberto.sassu@huawei.com>
Subject: Re: [PATCH v7 6/6] evm: Support multiple LSMs providing an xattr
Date: Mon, 20 Feb 2023 05:56:54 -0500 [thread overview]
Message-ID: <7bea1e47e85f8cb340a6ec4f7c04bc5e17c31b99.camel@linux.ibm.com> (raw)
In-Reply-To: <ab9245bfb43b96fd8eded8a4ca25f5cae20b9f04.camel@huaweicloud.com>
On Mon, 2023-02-20 at 10:49 +0100, Roberto Sassu wrote:
> On Sun, 2023-02-19 at 14:42 -0500, Mimi Zohar wrote:
> > On Thu, 2022-12-01 at 11:41 +0100, Roberto Sassu wrote:
> > > From: Roberto Sassu <roberto.sassu@huawei.com>
> > >
> > > Currently, evm_inode_init_security() processes a single LSM xattr from
> > > the array passed by security_inode_init_security(), and calculates the
> > > HMAC on it and other inode metadata.
> > >
> > > Given that initxattrs() callbacks, called by
> > > security_inode_init_security(), expect that this array is terminated when
> > > the xattr name is set to NULL, reuse the same assumption to scan all xattrs
> > > and to calculate the HMAC on all of them.
> > >
> > > Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
> > > Reviewed-by: Casey Schaufler <casey@schaufler-ca.com>
> >
> > Normally changing the contents of the EVM HMAC calculation would break
> > existing systems. Assuming for the time being this is safe, at what
> > point will it affect backwards compatability? Should it be documented
> > now or then?
>
> Actually, the current patch set continues to fullfill user space
> expectation on the EVM behavior. If the LSM infrastructure created more
> xattrs and EVM calculated the HMAC on just one, there would be a
> problem on subsequent xattr operations and on IMA verification.
>
> By updating both the LSM infrastructure and EVM to support multiple
> xattrs, everything will continue to work.
Agreed. Thank you for the reminder of the bug report being addressed
by this patch set.
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
--
thanks,
Mimi
next prev parent reply other threads:[~2023-02-20 10:58 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-12-01 10:41 [PATCH v7 0/6] evm: Do HMAC of multiple per LSM xattrs for new inodes Roberto Sassu
2022-12-01 10:41 ` [PATCH v7 1/6] reiserfs: Switch to security_inode_init_security() Roberto Sassu
2023-02-17 19:47 ` Mimi Zohar
2022-12-01 10:41 ` [PATCH v7 2/6] ocfs2: " Roberto Sassu
2023-01-10 8:55 ` Roberto Sassu
2023-01-12 17:21 ` Paul Moore
2023-02-08 14:33 ` Roberto Sassu
2023-02-09 21:05 ` Paul Moore
2023-02-21 6:45 ` Joseph Qi
2023-02-21 7:51 ` Roberto Sassu
2023-02-17 19:51 ` Mimi Zohar
2023-02-17 21:30 ` Mimi Zohar
2023-02-20 9:27 ` Roberto Sassu
2023-02-20 11:08 ` Mimi Zohar
2023-02-20 12:20 ` Roberto Sassu
2023-02-20 12:40 ` Mimi Zohar
2023-02-20 8:34 ` Roberto Sassu
2022-12-01 10:41 ` [PATCH v7 3/6] security: Remove security_old_inode_init_security() Roberto Sassu
2023-02-19 19:41 ` Mimi Zohar
2022-12-01 10:41 ` [PATCH v7 4/6] security: Allow all LSMs to provide xattrs for inode_init_security hook Roberto Sassu
2023-02-20 12:43 ` Mimi Zohar
2022-12-01 10:41 ` [PATCH v7 5/6] evm: Align evm_inode_init_security() definition with LSM infrastructure Roberto Sassu
2023-02-19 19:41 ` Mimi Zohar
2022-12-01 10:41 ` [PATCH v7 6/6] evm: Support multiple LSMs providing an xattr Roberto Sassu
2023-02-19 19:42 ` Mimi Zohar
2023-02-20 9:49 ` Roberto Sassu
2023-02-20 10:56 ` Mimi Zohar [this message]
2023-01-12 17:15 ` [PATCH v7 0/6] evm: Do HMAC of multiple per LSM xattrs for new inodes Paul Moore
2023-01-13 10:35 ` Roberto Sassu
2023-03-08 22:16 ` Paul Moore
2023-03-09 7:53 ` Roberto Sassu
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