crypto: rsa - return raw integers for the ASN.1 parser

Return the raw key with no other processing so that the caller
can copy it or MPI parse it, etc.

The scope is to have only one ANS.1 parser for all RSA
implementations.

Update the RSA software implementation so that it does
the MPI conversion on top.

Signed-off-by: Tudor Ambarus <tudor-dan.ambarus@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/crypto/internal/rsa.h

@@ -12,12 +12,24 @@
  */
 #ifndef _RSA_HELPER_
 #define _RSA_HELPER_
-#include <linux/mpi.h>
+#include <linux/types.h>
 
+/**
+ * rsa_key - RSA key structure
+ * @n           : RSA modulus raw byte stream
+ * @e           : RSA public exponent raw byte stream
+ * @d           : RSA private exponent raw byte stream
+ * @n_sz        : length in bytes of RSA modulus n
+ * @e_sz        : length in bytes of RSA public exponent
+ * @d_sz        : length in bytes of RSA private exponent
+ */
 struct rsa_key {
-	MPI n;
-	MPI e;
-	MPI d;
+	const u8 *n;
+	const u8 *e;
+	const u8 *d;
+	size_t n_sz;
+	size_t e_sz;
+	size_t d_sz;
 };
 
 int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
@@ -26,7 +38,5 @@ int rsa_parse_pub_key(struct rsa_key *rsa_key, const void *key,
 int rsa_parse_priv_key(struct rsa_key *rsa_key, const void *key,
 		       unsigned int key_len);
 
-void rsa_free_key(struct rsa_key *rsa_key);
-
 extern struct crypto_template rsa_pkcs1pad_tmpl;
 #endif