KEYS: asym_tpm: extract key size & public key [ver #2]

The parsed BER/DER blob obtained from user space contains a TPM_Key
structure.  This structure has some information about the key as well as
the public key portion.

This patch extracts this information for future use.

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>

include/crypto/asym_tpm_subtype.h

@@ -7,6 +7,9 @@
 struct tpm_key {
 	void *blob;
 	u32 blob_len;
+	uint16_t key_len; /* Size in bits of the key */
+	const void *pub_key; /* pointer inside blob to the public key bytes */
+	uint16_t pub_key_len; /* length of the public key */
 };
 
 struct tpm_key *tpm_key_create(const void *blob, uint32_t blob_len);