lib: crypt: Prepare the existing code to switch to Intel AES hardware instructions.

Rename the old struct aes_key as an intermediate struct aes_key_rj
and wrap it in a union so we can chose an alternate aes_key struct
when using Intel AES hardware.

Rename the original software implementations of:

 AES_set_encrypt_key()
 AES_set_decrypt_key()
 AES_encrypt()
 AES_decrypt()

by adding an _rj on the end, and call them via a wrapper
function.

BUG: https://bugzilla.samba.org/show_bug.cgi?id=13008

Based on original work by Justin Maggard <jmaggard@netgear.com>

Signed-off-by: Jeremy Allison <jra@samba.org>
Reviewed-by: Stefan Metzmacher <metze@samba.org>

2 files changed, 67 insertions, 11 deletions

diff --git a/lib/crypto/aes.c b/lib/crypto/aes.c
index 800a97ee705..8e6d8418f16 100644
--- a/lib/crypto/aes.c
+++ b/lib/crypto/aes.c
@@ -37,35 +37,85 @@
 #ifdef SAMBA_RIJNDAEL
 #include "rijndael-alg-fst.h"
 
-int
-AES_set_encrypt_key(const unsigned char *userkey, const int bits, AES_KEY *key)
+/*
+ * The next 4 functions are the pure software implementations
+ * of:
+ *
+ * AES_set_encrypt_key()
+ * AES_set_decrypt_key()
+ * AES_encrypt()
+ * AES_decrypt()
+ */
+
+static int
+AES_set_encrypt_key_rj(const unsigned char *userkey, const int bits, AES_KEY *key)
 {
-    key->rounds = rijndaelKeySetupEnc(key->key, userkey, bits);
-    if (key->rounds == 0)
+    key->u.aes_rj.rounds = rijndaelKeySetupEnc(key->u.aes_rj.key, userkey, bits);
+    if (key->u.aes_rj.rounds == 0)
 	return -1;
     return 0;
 }
 
-int
-AES_set_decrypt_key(const unsigned char *userkey, const int bits, AES_KEY *key)
+static int
+AES_set_decrypt_key_rj(const unsigned char *userkey, const int bits, AES_KEY *key)
 {
-    key->rounds = rijndaelKeySetupDec(key->key, userkey, bits);
-    if (key->rounds == 0)
+    key->u.aes_rj.rounds = rijndaelKeySetupDec(key->u.aes_rj.key, userkey, bits);
+    if (key->u.aes_rj.rounds == 0)
 	return -1;
     return 0;
 }
 
+static void
+AES_encrypt_rj(const unsigned char *in, unsigned char *out, const AES_KEY *key)
+{
+    rijndaelEncrypt(key->u.aes_rj.key, key->u.aes_rj.rounds, in, out);
+}
+
+static void
+AES_decrypt_rj(const unsigned char *in, unsigned char *out, const AES_KEY *key)
+{
+    rijndaelDecrypt(key->u.aes_rj.key, key->u.aes_rj.rounds, in, out);
+}
+
+/*
+ * The next 4 functions are the runtime switch for Intel AES hardware
+ * implementations of:
+ *
+ * AES_set_encrypt_key()
+ * AES_set_decrypt_key()
+ * AES_encrypt()
+ * AES_decrypt()
+ *
+ * If the hardware instructions don't exist, fall back to the software
+ * versions.
+ *
+ * Currently only use the software implementations.
+ */
+
+int
+AES_set_encrypt_key(const unsigned char *userkey, const int bits, AES_KEY *key)
+{
+	return AES_set_encrypt_key_rj(userkey, bits, key);
+}
+
+int
+AES_set_decrypt_key(const unsigned char *userkey, const int bits, AES_KEY *key)
+{
+	return AES_set_decrypt_key_rj(userkey, bits, key);
+}
+
 void
 AES_encrypt(const unsigned char *in, unsigned char *out, const AES_KEY *key)
 {
-    rijndaelEncrypt(key->key, key->rounds, in, out);
+	return AES_encrypt_rj(in, out, key);
 }
 
 void
 AES_decrypt(const unsigned char *in, unsigned char *out, const AES_KEY *key)
 {
-    rijndaelDecrypt(key->key, key->rounds, in, out);
+	return AES_decrypt_rj(in, out, key);
 }
+
 #endif /* SAMBA_RIJNDAEL */
 
 #ifdef SAMBA_AES_CBC_ENCRYPT
diff --git a/lib/crypto/aes.h b/lib/crypto/aes.h
index 48ea764d514..0ab0a376757 100644
--- a/lib/crypto/aes.h
+++ b/lib/crypto/aes.h
@@ -59,9 +59,15 @@
 #define AES_ENCRYPT 1
 #define AES_DECRYPT 0
 
-typedef struct aes_key {
+struct aes_key_rj {
     uint32_t key[(AES_MAXNR+1)*4];
     int rounds;
+};
+
+typedef struct aes_key {
+	union {
+		struct aes_key_rj aes_rj;
+	} u;
 } AES_KEY;
 
 #ifdef __cplusplus