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From:   GUO Zihua <guozihua@huawei.com>
To:     <corbet@lwn.net>, <zohar@linux.ibm.com>
CC:     <linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <roberto.sassu@huawei.com>, <wangweiyang2@huawei.com>,
        <xiujianfeng@huawei.com>, <linux-integrity@vger.kernel.org>,
        <guozihua@huawei.com>
Subject: [RESEND][PATCH] Documentation: added order requirement for ima_hash=
Date:   Tue, 25 Jan 2022 17:02:37 +0800
Message-ID: <20220125090237.120357-1-guozihua@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk

From: Guo Zihua <guozihua@huawei.com>

Commandline parameter ima_hash= and ima_template= has order requirement
for them to work correctly together. Namely ima_hash= must be
specified after ima_template=, otherwise ima_template= will be ignored.

The reason is that when handling ima_hash=, ima template would be set to
the default value if it has not been initialized already, and that value
cannot be changed afterwards by ima_template=.

This patch adds this limitation to the documentation.

Reviewed-by: Roberto Sassu <roberto.sassu@huawei.com>
Signed-off-by: Guo Zihua <guozihua@huawei.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index f5a27f067db9..1b5aa6ca65f8 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -1843,6 +1843,10 @@
 			The list of supported hash algorithms is defined
 			in crypto/hash_info.h.
 
+			This parameter must be specified after ima_template=,
+			as it would set the default template and that cannot be
+			changed by ima_template= afterwards.
+
 	ima_policy=	[IMA]
 			The builtin policies to load during IMA setup.
 			Format: "tcb | appraise_tcb | secure_boot |
@@ -1879,6 +1883,9 @@
 			Formats: { "ima" | "ima-ng" | "ima-sig" }
 			Default: "ima-ng"
 
+			This parameter must be specified before ima_hash=.
+			Please refer to ima_hash= for further explanation.
+
 	ima_template_fmt=
 			[IMA] Define a custom template format.
 			Format: { "field1|...|fieldN" }
-- 
2.17.1