SMB3.1.1: Add GCM crypto to the encrypt and decrypt functions

SMB3.1.1 GCM performs much better than the older CCM default:
more than twice as fast in the write patch (copy to the Samba
server on localhost for example) and 80% faster on the read
patch (copy from the server).
Signed-off-by: NSteve French <stfrench@microsoft.com>
Reviewed-by: NRonnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: NPavel Shilovsky <pshilov@microsoft.com>

fs/cifs/smb2ops.c

@@ -3367,7 +3367,7 @@ smb2_dir_needs_close(struct cifsFileInfo *cfile)
 
 static void
 fill_transform_hdr(struct smb2_transform_hdr *tr_hdr, unsigned int orig_len,
-		   struct smb_rqst *old_rq)
+		   struct smb_rqst *old_rq, __le16 cipher_type)
 {
 	struct smb2_sync_hdr *shdr =
 			(struct smb2_sync_hdr *)old_rq->rq_iov[0].iov_base;
@@ -3376,6 +3376,9 @@ fill_transform_hdr(struct smb2_transform_hdr *tr_hdr, unsigned int orig_len,
 	tr_hdr->ProtocolId = SMB2_TRANSFORM_PROTO_NUM;
 	tr_hdr->OriginalMessageSize = cpu_to_le32(orig_len);
 	tr_hdr->Flags = cpu_to_le16(0x01);
+	if (cipher_type == SMB2_ENCRYPTION_AES128_GCM)
+		get_random_bytes(&tr_hdr->Nonce, SMB3_AES128GCM_NONCE);
+	else
 		get_random_bytes(&tr_hdr->Nonce, SMB3_AES128CCM_NONCE);
 	memcpy(&tr_hdr->SessionId, &shdr->SessionId, 8);
 }
@@ -3534,8 +3537,13 @@ crypt_message(struct TCP_Server_Info *server, int num_rqst,
 		rc = -ENOMEM;
 		goto free_sg;
 	}
+
+	if (server->cipher_type == SMB2_ENCRYPTION_AES128_GCM)
+		memcpy(iv, (char *)tr_hdr->Nonce, SMB3_AES128GCM_NONCE);
+	else {
 		iv[0] = 3;
 		memcpy(iv + 1, (char *)tr_hdr->Nonce, SMB3_AES128CCM_NONCE);
+	}
 
 	aead_request_set_crypt(req, sg, sg, crypt_len, iv);
 	aead_request_set_ad(req, assoc_data_len);
@@ -3635,7 +3643,7 @@ smb3_init_transform_rq(struct TCP_Server_Info *server, int num_rqst,
 	}
 
 	/* fill the 1st iov with a transform header */
-	fill_transform_hdr(tr_hdr, orig_len, old_rq);
+	fill_transform_hdr(tr_hdr, orig_len, old_rq, server->cipher_type);
 
 	rc = crypt_message(server, num_rqst, new_rq, 1);
 	cifs_dbg(FYI, "Encrypt message returned %d\n", rc);

fs/cifs/smb2transport.c

@@ -734,6 +734,9 @@ smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
 	struct crypto_aead *tfm;
 
 	if (!server->secmech.ccmaesencrypt) {
+		if (server->cipher_type == SMB2_ENCRYPTION_AES128_GCM)
+			tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
+		else
 			tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
 		if (IS_ERR(tfm)) {
 			cifs_dbg(VFS, "%s: Failed to alloc encrypt aead\n",
@@ -744,6 +747,9 @@ smb3_crypto_aead_allocate(struct TCP_Server_Info *server)
 	}
 
 	if (!server->secmech.ccmaesdecrypt) {
+		if (server->cipher_type == SMB2_ENCRYPTION_AES128_GCM)
+			tfm = crypto_alloc_aead("gcm(aes)", 0, 0);
+		else
 			tfm = crypto_alloc_aead("ccm(aes)", 0, 0);
 		if (IS_ERR(tfm)) {
 			crypto_free_aead(server->secmech.ccmaesencrypt);