From: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
To: zohar@linux.ibm.com, linux-integrity@vger.kernel.org
Cc: eric.snowberg@oracle.com, dhowells@redhat.com,
matthewgarrett@google.com, sashal@kernel.org,
jamorris@linux.microsoft.com, linux-kernel@vger.kernel.org,
keyrings@vger.kernel.org
Subject: [PATCH v9 3/6] IMA: Define an IMA hook to measure keys
Date: Tue, 26 Nov 2019 17:56:51 -0800 [thread overview]
Message-ID: <20191127015654.3744-4-nramas@linux.microsoft.com> (raw)
In-Reply-To: <20191127015654.3744-1-nramas@linux.microsoft.com>
Measure asymmetric keys used for verifying file signatures,
certificates, etc.
This patch defines a new IMA hook namely ima_post_key_create_or_update()
to measure the payload used to create a new key or update an existing key.
The IMA hook is defined in a new file namely ima_asymmetric_keys.c
which is built only if CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE is enabled.
Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
---
security/integrity/ima/Makefile | 1 +
security/integrity/ima/ima_asymmetric_keys.c | 52 ++++++++++++++++++++
2 files changed, 53 insertions(+)
create mode 100644 security/integrity/ima/ima_asymmetric_keys.c
diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index 31d57cdf2421..207a0a9eb72c 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -12,3 +12,4 @@ ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
ima-$(CONFIG_IMA_APPRAISE_MODSIG) += ima_modsig.o
ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o
obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o
+obj-$(CONFIG_ASYMMETRIC_PUBLIC_KEY_SUBTYPE) += ima_asymmetric_keys.o
diff --git a/security/integrity/ima/ima_asymmetric_keys.c b/security/integrity/ima/ima_asymmetric_keys.c
new file mode 100644
index 000000000000..2308adcdeff3
--- /dev/null
+++ b/security/integrity/ima/ima_asymmetric_keys.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Microsoft Corporation
+ *
+ * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
+ *
+ * File: ima_asymmetric_keys.c
+ * Defines an IMA hook to measure asymmetric keys on key
+ * create or update.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <keys/asymmetric-type.h>
+#include "ima.h"
+
+/**
+ * ima_post_key_create_or_update - measure asymmetric keys
+ * @keyring: keyring to which the key is linked to
+ * @key: created or updated key
+ * @payload: The data used to instantiate or update the key.
+ * @plen: The length of @payload.
+ * @flags: key flags
+ * @create: flag indicating whether the key was created or updated
+ *
+ * Keys can only be measured, not appraised.
+ * The payload data used to instantiate or update the key is measured.
+ */
+void ima_post_key_create_or_update(struct key *keyring, struct key *key,
+ const void *payload, size_t plen,
+ unsigned long flags, bool create)
+{
+ /* Only asymmetric keys are handled by this hook. */
+ if (key->type != &key_type_asymmetric)
+ return;
+
+ if (!payload || (plen == 0))
+ return;
+
+ /*
+ * keyring->description points to the name of the keyring
+ * (such as ".builtin_trusted_keys", ".ima", etc.) to
+ * which the given key is linked to.
+ *
+ * The name of the keyring is passed in the "eventname"
+ * parameter to process_buffer_measurement() and is set
+ * in the "eventname" field in ima_event_data for
+ * the key measurement IMA event.
+ */
+ process_buffer_measurement(payload, plen,
+ keyring->description, KEY_CHECK, 0);
+}
--
2.17.1
next prev parent reply other threads:[~2019-11-27 1:57 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-27 1:56 [PATCH v9 0/6] KEYS: Measure keys when they are created or updated Lakshmi Ramasubramanian
2019-11-27 1:56 ` [PATCH v9 1/6] IMA: Check IMA policy flag Lakshmi Ramasubramanian
2019-11-27 1:56 ` [PATCH v9 2/6] IMA: Add KEY_CHECK func to measure keys Lakshmi Ramasubramanian
2019-11-27 1:56 ` Lakshmi Ramasubramanian [this message]
2019-11-27 1:56 ` [PATCH v9 4/6] KEYS: Call the IMA hook " Lakshmi Ramasubramanian
2019-11-27 1:56 ` [PATCH v9 5/6] IMA: Add support to limit measuring keys Lakshmi Ramasubramanian
2019-11-27 18:52 ` Mimi Zohar
2019-11-28 0:44 ` Lakshmi Ramasubramanian
2019-12-02 18:18 ` Mimi Zohar
2019-12-03 12:25 ` Mimi Zohar
2019-12-03 16:13 ` Lakshmi Ramasubramanian
2019-12-03 16:47 ` Mimi Zohar
2019-12-03 19:45 ` Lakshmi Ramasubramanian
2019-12-03 20:06 ` Mimi Zohar
2019-12-03 23:37 ` Lakshmi Ramasubramanian
2019-12-04 11:16 ` Mimi Zohar
2019-12-04 22:43 ` Lakshmi Ramasubramanian
2019-12-04 23:25 ` Mat Martineau
2019-11-27 1:56 ` [PATCH v9 6/6] IMA: Read keyrings= option from the IMA policy Lakshmi Ramasubramanian
2019-11-27 19:32 ` Mimi Zohar
2019-11-27 22:05 ` Lakshmi Ramasubramanian
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