crypto: aesni - add wrapper for generic gcm(aes)

When I added generic-gcm-aes I didn't add a wrapper like the one
provided for rfc4106(gcm(aes)). We need to add a cryptd wrapper to fall
back on in case the FPU is not available, otherwise we might corrupt the
FPU state.

Fixes: cce2ea8d90fe ("crypto: aesni - add generic gcm(aes)")
Cc: <[e-mail]>
Reported-by: Ilya Lesokhin <[e-mail]>
Signed-off-by: Sabrina Dubroca <[e-mail]>
Reviewed-by: Stefano Brivio <[e-mail]>
Signed-off-by: Herbert Xu <[e-mail]>

arch/x86/crypto/aesni-intel_glue.c

···
 	       rfc4106_set_hash_subkey(ctx->hash_subkey, key, key_len);
 }
 
-static int rfc4106_set_key(struct crypto_aead *parent, const u8 *key,
-			   unsigned int key_len)
+static int gcmaes_wrapper_set_key(struct crypto_aead *parent, const u8 *key,
+				  unsigned int key_len)
 {
 	struct cryptd_aead **ctx = crypto_aead_ctx(parent);
 	struct cryptd_aead *cryptd_tfm = *ctx;
···
 
 /* This is the Integrity Check Value (aka the authentication tag length and can
  * be 8, 12 or 16 bytes long. */
-static int rfc4106_set_authsize(struct crypto_aead *parent,
-				unsigned int authsize)
+static int gcmaes_wrapper_set_authsize(struct crypto_aead *parent,
+				       unsigned int authsize)
 {
 	struct cryptd_aead **ctx = crypto_aead_ctx(parent);
 	struct cryptd_aead *cryptd_tfm = *ctx;
···
 			      aes_ctx);
 }
 
-static int rfc4106_encrypt(struct aead_request *req)
+static int gcmaes_wrapper_encrypt(struct aead_request *req)
 {
 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 	struct cryptd_aead **ctx = crypto_aead_ctx(tfm);
···
 	return crypto_aead_encrypt(req);
 }
 
-static int rfc4106_decrypt(struct aead_request *req)
+static int gcmaes_wrapper_decrypt(struct aead_request *req)
 {
 	struct crypto_aead *tfm = crypto_aead_reqtfm(req);
 	struct cryptd_aead **ctx = crypto_aead_ctx(tfm);
···
 			      aes_ctx);
 }
 
+static int generic_gcmaes_init(struct crypto_aead *aead)
+{
+	struct cryptd_aead *cryptd_tfm;
+	struct cryptd_aead **ctx = crypto_aead_ctx(aead);
+
+	cryptd_tfm = cryptd_alloc_aead("__driver-generic-gcm-aes-aesni",
+				       CRYPTO_ALG_INTERNAL,
+				       CRYPTO_ALG_INTERNAL);
+	if (IS_ERR(cryptd_tfm))
+		return PTR_ERR(cryptd_tfm);
+
+	*ctx = cryptd_tfm;
+	crypto_aead_set_reqsize(aead, crypto_aead_reqsize(&cryptd_tfm->base));
+
+	return 0;
+}
+
+static void generic_gcmaes_exit(struct crypto_aead *aead)
+{
+	struct cryptd_aead **ctx = crypto_aead_ctx(aead);
+
+	cryptd_free_aead(*ctx);
+}
+
 static struct aead_alg aesni_aead_algs[] = { {
 	.setkey			= common_rfc4106_set_key,
 	.setauthsize		= common_rfc4106_set_authsize,
···
 }, {
 	.init			= rfc4106_init,
 	.exit			= rfc4106_exit,
-	.setkey			= rfc4106_set_key,
-	.setauthsize		= rfc4106_set_authsize,
-	.encrypt		= rfc4106_encrypt,
-	.decrypt		= rfc4106_decrypt,
+	.setkey			= gcmaes_wrapper_set_key,
+	.setauthsize		= gcmaes_wrapper_set_authsize,
+	.encrypt		= gcmaes_wrapper_encrypt,
+	.decrypt		= gcmaes_wrapper_decrypt,
 	.ivsize			= GCM_RFC4106_IV_SIZE,
 	.maxauthsize		= 16,
 	.base = {
···
 	.ivsize			= GCM_AES_IV_SIZE,
 	.maxauthsize		= 16,
 	.base = {
+		.cra_name		= "__generic-gcm-aes-aesni",
+		.cra_driver_name	= "__driver-generic-gcm-aes-aesni",
+		.cra_priority		= 0,
+		.cra_flags		= CRYPTO_ALG_INTERNAL,
+		.cra_blocksize		= 1,
+		.cra_ctxsize		= sizeof(struct generic_gcmaes_ctx),
+		.cra_alignmask		= AESNI_ALIGN - 1,
+		.cra_module		= THIS_MODULE,
+	},
+}, {
+	.init			= generic_gcmaes_init,
+	.exit			= generic_gcmaes_exit,
+	.setkey			= gcmaes_wrapper_set_key,
+	.setauthsize		= gcmaes_wrapper_set_authsize,
+	.encrypt		= gcmaes_wrapper_encrypt,
+	.decrypt		= gcmaes_wrapper_decrypt,
+	.ivsize			= GCM_AES_IV_SIZE,
+	.maxauthsize		= 16,
+	.base = {
 		.cra_name		= "gcm(aes)",
 		.cra_driver_name	= "generic-gcm-aesni",
 		.cra_priority		= 400,
 		.cra_flags		= CRYPTO_ALG_ASYNC,
 		.cra_blocksize		= 1,
-		.cra_ctxsize		= sizeof(struct generic_gcmaes_ctx),
-		.cra_alignmask		= AESNI_ALIGN - 1,
+		.cra_ctxsize		= sizeof(struct cryptd_aead *),
 		.cra_module		= THIS_MODULE,
 	},
 } };