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From:   Tianjia Zhang <tianjia.zhang@linux.alibaba.com>
To:     zohar@linux.ibm.com, dmitry.kasatkin@gmail.com, jmorris@namei.org,
        serge@hallyn.com, zhangliguang@linux.alibaba.com
Cc:     linux-integrity@vger.kernel.org,
        linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 0/2] support to read and tune appraise mode in runtime
Date:   Thu,  9 Apr 2020 11:39:05 +0800
Message-Id: <20200409033907.102833-1-tianjia.zhang@linux.alibaba.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Support the read and write operations of ima_appraise by adding a
securifyfs file 'appraise_mode'.

In order to tune appraise mode in runtime, writing a PKCS#7 signature
corresponding the signed content is required. The content should be off,
enforce, log or fix. Given a simple way to archive this:

$ echo -n off > mode
$ openssl smime -sign -nocerts -noattr -binary \
    -in mode -inkey <system_trusted_key> \
    -signer <cert> -outform der -out mode.p7s
$ sudo cat mode.p7s \
    > /sys/kernel/security/ima/appraise_mode

Note that the signing key must be a trust key located in
system trusted keyring. So even the root privilege cannot
simply disable the enforcement.

Tianjia Zhang (2):
  ima: support to read appraise mode
  ima: support to tune appraise mode in runtime

 security/integrity/ima/ima_fs.c | 134 +++++++++++++++++++++++++++++++-
 1 file changed, 133 insertions(+), 1 deletion(-)

-- 
2.17.1