KEYS: Add parser for TPM-based keys [ver #2]

For TPM based keys, the only standard seems to be described here:
http://david.woodhou.se/draft-woodhouse-cert-best-practice.html#rfc.section.4.4

Quote from the relevant section:
"Rather, a common form of storage for "wrapped" keys is to encode the
binary TCPA_KEY structure in a single ASN.1 OCTET-STRING, and store the
result in PEM format with the tag "-----BEGIN TSS KEY BLOB-----". "

This patch implements the above behavior.  It is assumed that the PEM
encoding is stripped out by userspace and only the raw DER/BER format is
provided.  This is similar to how PKCS7, PKCS8 and X.509 keys are
handled.

Signed-off-by: Denis Kenzior <denkenz@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Marcel Holtmann <marcel@holtmann.org>
Reviewed-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: James Morris <james.morris@microsoft.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/crypto/asymmetric_keys/Kconfig b/crypto/asymmetric_keys/Kconfig
index b75555c7..88353a9e 100644
--- a/crypto/asymmetric_keys/Kconfig
+++ b/crypto/asymmetric_keys/Kconfig
@@ -52,6 +52,15 @@ config PKCS8_PRIVATE_KEY_PARSER
 	  private key data and provides the ability to instantiate a crypto key
 	  from that data.
 
+config TPM_KEY_PARSER
+	tristate "TPM private key parser"
+	depends on ASYMMETRIC_TPM_KEY_SUBTYPE
+	select ASN1
+	help
+	  This option provides support for parsing TPM format blobs for
+	  private key data and provides the ability to instantiate a crypto key
+	  from that data.
+
 config PKCS7_MESSAGE_PARSER
 	tristate "PKCS#7 message parser"
 	depends on X509_CERTIFICATE_PARSER