From: Mimi Zohar <zohar@linux.ibm.com>
To: Roberto Sassu <roberto.sassu@huawei.com>,
"matthewgarrett@google.com" <matthewgarrett@google.com>
Cc: "linux-integrity@vger.kernel.org"
<linux-integrity@vger.kernel.org>,
Silviu Vlasceanu <Silviu.Vlasceanu@huawei.com>
Subject: Re: Immutable metadata
Date: Sun, 29 Mar 2020 22:10:23 -0400 [thread overview]
Message-ID: <1585534223.5188.408.camel@linux.ibm.com> (raw)
In-Reply-To: <ff12bbbd945545a988ef84d6e4d3b83d@huawei.com>
Hi Roberto,
On Sat, 2020-03-28 at 11:18 +0000, Roberto Sassu wrote:
> Hi Matthew, Mimi
>
> I have a question about portable signatures. Is there any particular reason
> why a write to a file is not denied by IMA if metadata are immutable?
As much as possible, IMA and EVM should be independent of each other.
EVM is responsible for the integrity of file metadata, so it needs to
read other security xattrs, but IMA shouldn't be looking at the EVM
xattr.
Like any other security xattr, responsibility for maintaining the
xattr is left up to the particular LSM. In this case, EVM would need
to prevent the file from being opened rw. Should that be hard coded
or based on an EVM policy?
Mimi
next prev parent reply other threads:[~2020-03-30 2:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-28 11:18 Immutable metadata Roberto Sassu
2020-03-30 2:10 ` Mimi Zohar [this message]
2020-03-30 15:46 ` Mimi Zohar
2020-03-30 15:56 ` Roberto Sassu
2020-03-30 18:36 ` Mimi Zohar
2020-03-31 6:56 ` Roberto Sassu
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