[RFC 5/7] KEYS: encrypted: Allow TEE based trusted master keys

From: Sumit Garg <sumit.garg@linaro.org>
To: keyrings@vger.kernel.org, linux-integrity@vger.kernel.org,
	linux-security-module@vger.kernel.org
Cc: jens.wiklander@linaro.org, corbet@lwn.net, dhowells@redhat.com,
	jejb@linux.ibm.com, jarkko.sakkinen@linux.intel.com,
	zohar@linux.ibm.com, jmorris@namei.org, serge@hallyn.com,
	ard.biesheuvel@linaro.org, daniel.thompson@linaro.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	tee-dev@lists.linaro.org, Sumit Garg <sumit.garg@linaro.org>
Subject: [RFC 5/7] KEYS: encrypted: Allow TEE based trusted master keys
Date: Thu, 13 Jun 2019 16:00:31 +0530	[thread overview]
Message-ID: <1560421833-27414-6-git-send-email-sumit.garg@linaro.org> (raw)
In-Reply-To: <1560421833-27414-1-git-send-email-sumit.garg@linaro.org>

Allow search for TEE based trusted keys to act as master keys in case
TPM device is not present.

Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
---
 security/keys/encrypted-keys/masterkey_trusted.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/security/keys/encrypted-keys/masterkey_trusted.c b/security/keys/encrypted-keys/masterkey_trusted.c
index c68528a..cfac27f 100644
--- a/security/keys/encrypted-keys/masterkey_trusted.c
+++ b/security/keys/encrypted-keys/masterkey_trusted.c
@@ -23,6 +23,9 @@
  * Trusted keys are sealed to PCRs and other metadata. Although userspace
  * manages both trusted/encrypted key-types, like the encrypted key type
  * data, trusted key type data is not visible decrypted from userspace.
+ *
+ * Also, check for alternate trusted keys provided via TEE in case there
+ * is no TPM available.
  */
 struct key *request_trusted_key(const char *trusted_desc,
 				const u8 **master_key, size_t *master_keylen)
@@ -31,8 +34,11 @@ struct key *request_trusted_key(const char *trusted_desc,
 	struct key *tkey;
 
 	tkey = request_key(&key_type_trusted, trusted_desc, NULL);
-	if (IS_ERR(tkey))
-		goto error;
+	if (IS_ERR(tkey)) {
+		tkey = request_key(&key_type_tee_trusted, trusted_desc, NULL);
+		if (IS_ERR(tkey))
+			goto error;
+	}
 
 	down_read(&tkey->sem);
 	tpayload = tkey->payload.data[0];
-- 
2.7.4

