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From: Roberto Sassu <roberto.sassu@huawei.com>
To: <zohar@linux.ibm.com>, <mjg59@google.com>
Cc: <linux-integrity@vger.kernel.org>,
	<linux-security-module@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <silviu.vlasceanu@huawei.com>,
	Roberto Sassu <roberto.sassu@huawei.com>
Subject: [PATCH v2 05/12] evm: Load EVM key in ima_load_x509() to avoid appraisal
Date: Fri, 4 Sep 2020 11:26:36 +0200	[thread overview]
Message-ID: <20200904092643.20013-1-roberto.sassu@huawei.com> (raw)
In-Reply-To: <20200904092339.19598-1-roberto.sassu@huawei.com>

Public keys do not need to be appraised by IMA as the restriction on the
IMA/EVM keyrings ensures that a key is loaded only if it is signed with a
key in the primary or secondary keyring.

However, when evm_load_x509() is loaded, appraisal is already enabled and
a valid IMA signature must be added to the EVM key to pass verification.

Since the restriction is applied on both IMA and EVM keyrings, it is safe
to disable appraisal also when the EVM key is loaded. This patch calls
evm_load_x509() inside ima_load_x509() if CONFIG_IMA_LOAD_X509 is defined.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Mimi Zohar <zohar@linux.ibm.com>
---
 security/integrity/iint.c         | 2 ++
 security/integrity/ima/ima_init.c | 4 ++++
 2 files changed, 6 insertions(+)

diff --git a/security/integrity/iint.c b/security/integrity/iint.c
index 1d20003243c3..7d08c31c612f 100644
--- a/security/integrity/iint.c
+++ b/security/integrity/iint.c
@@ -200,7 +200,9 @@ int integrity_kernel_read(struct file *file, loff_t offset,
 void __init integrity_load_keys(void)
 {
 	ima_load_x509();
+#ifndef CONFIG_IMA_LOAD_X509
 	evm_load_x509();
+#endif
 }
 
 static int __init integrity_fs_init(void)
diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 4902fe7bd570..9d29a1680da8 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -106,6 +106,10 @@ void __init ima_load_x509(void)
 
 	ima_policy_flag &= ~unset_flags;
 	integrity_load_x509(INTEGRITY_KEYRING_IMA, CONFIG_IMA_X509_PATH);
+
+	/* load also EVM key to avoid appraisal */
+	evm_load_x509();
+
 	ima_policy_flag |= unset_flags;
 }
 #endif
-- 
2.27.GIT


  parent reply	other threads:[~2020-09-04  9:30 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-04  9:23 [PATCH v2 00/12] IMA/EVM fixes Roberto Sassu
2020-09-04  9:23 ` [PATCH v2 01/12] ima: Don't ignore errors from crypto_shash_update() Roberto Sassu
2020-09-07 15:03   ` Sasha Levin
2020-09-04  9:23 ` [PATCH v2 02/12] ima: Remove semicolon at the end of ima_get_binary_runtime_size() Roberto Sassu
2020-09-04  9:23 ` [PATCH v2 03/12] evm: Check size of security.evm before using it Roberto Sassu
2020-09-04  9:23 ` [PATCH v2 04/12] evm: Execute evm_inode_init_security() only when the HMAC key is loaded Roberto Sassu
2020-09-07 15:03   ` Sasha Levin
2020-09-16 16:15   ` Mimi Zohar
2020-09-04  9:26 ` Roberto Sassu [this message]
2020-09-04  9:26 ` [PATCH v2 06/12] evm: Refuse EVM_ALLOW_METADATA_WRITES only if " Roberto Sassu
2020-09-04  9:26 ` [PATCH v2 07/12] evm: Introduce EVM_RESET_STATUS atomic flag Roberto Sassu
2020-09-17 12:01   ` Mimi Zohar
2020-09-17 17:36     ` Roberto Sassu
2020-09-17 17:47       ` Mimi Zohar
2020-09-04  9:26 ` [PATCH v2 08/12] evm: Allow xattr/attr operations for portable signatures if check fails Roberto Sassu
2020-09-17 12:32   ` Mimi Zohar
2020-09-04  9:26 ` [PATCH v2 09/12] evm: Allow setxattr() and setattr() if metadata digest won't change Roberto Sassu
2020-09-17 13:15   ` Mimi Zohar
2020-09-04  9:26 ` [PATCH v2 10/12] ima: Allow imasig requirement to be satisfied by EVM portable signatures Roberto Sassu
2020-09-04  9:26 ` [PATCH v2 11/12] ima: Introduce template field evmsig and write to field sig as fallback Roberto Sassu
2020-09-17 14:25   ` Mimi Zohar
2020-09-17 15:05     ` Roberto Sassu
2020-09-17 15:55       ` Mimi Zohar
2020-09-04  9:26 ` [PATCH v2 12/12] ima: Don't remove security.ima if file must not be appraised Roberto Sassu
2020-09-16 16:14 ` [PATCH v2 00/12] IMA/EVM fixes Mimi Zohar
2020-09-17 14:33   ` Mimi Zohar

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