From d693c836b1d5f37d9dae8a6dbefc7b731863eacb Mon Sep 17 00:00:00 2001
From: Andreas Schneider <asn@samba.org>
Date: Wed, 27 Feb 2019 14:40:30 +0100
Subject: [PATCH 119/187] libcli:smb: Use GnuTLS AES128 CMAC in
 smb2_signing_sign_pdu()

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

Adapted by Andrew Bartlett to followup from earlier patch to
allow compile without GnuTLS over the whole series.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit ee11e3ffd8d801cb5988bb73dbccd1e2f0cbe7b0)
---
 libcli/smb/smb2_signing.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/libcli/smb/smb2_signing.c b/libcli/smb/smb2_signing.c
index 01027d55fbe..b7c0be528b7 100644
--- a/libcli/smb/smb2_signing.c
+++ b/libcli/smb/smb2_signing.c
@@ -24,6 +24,11 @@
 #include "../lib/crypto/crypto.h"
 #include "lib/util/iov_buf.h"
 
+#ifndef HAVE_GNUTLS_AES_CMAC
+#include "lib/crypto/aes.h"
+#include "lib/crypto/aes_cmac_128.h"
+#endif
+
 #include "lib/crypto/gnutls_helpers.h"
 #include <gnutls/gnutls.h>
 #include <gnutls/crypto.h>
@@ -96,6 +101,33 @@ NTSTATUS smb2_signing_sign_pdu(struct smb2_signing_key *signing_key,
 	SIVAL(hdr, SMB2_HDR_FLAGS, IVAL(hdr, SMB2_HDR_FLAGS) | SMB2_HDR_FLAG_SIGNED);
 
 	if (protocol >= PROTOCOL_SMB2_24) {
+#ifdef HAVE_GNUTLS_AES_CMAC
+		gnutls_datum_t key = {
+			.data = signing_key->blob.data,
+			.size = MIN(signing_key->blob.length, 16),
+		};
+		int rc;
+
+		if (signing_key->hmac_hnd == NULL) {
+			rc = gnutls_hmac_init(&signing_key->hmac_hnd,
+					      GNUTLS_MAC_AES_CMAC_128,
+					      key.data,
+					      key.size);
+			if (rc < 0) {
+				return NT_STATUS_NO_MEMORY;
+			}
+		}
+
+		for (i = 0; i < count; i++) {
+			rc = gnutls_hmac(signing_key->hmac_hnd,
+					 vector[i].iov_base,
+					 vector[i].iov_len);
+			if (rc < 0) {
+				return NT_STATUS_INTERNAL_ERROR;
+			}
+		}
+		gnutls_hmac_output(signing_key->hmac_hnd, res);
+#else /* NOT HAVE_GNUTLS_AES_CMAC */
 		struct aes_cmac_128_context ctx;
 		uint8_t key[AES_BLOCK_SIZE] = {0};
 
@@ -112,6 +144,7 @@ NTSTATUS smb2_signing_sign_pdu(struct smb2_signing_key *signing_key,
 		aes_cmac_128_final(&ctx, res);
 
 		ZERO_ARRAY(key);
+#endif /* HAVE_GNUTLS_AES_CMAC */
 	} else {
 		uint8_t digest[gnutls_hmac_get_len(GNUTLS_MAC_SHA256)];
 		int rc;
-- 
2.23.0