From 9b5fa6c165e98ddec38bc976bac0cfee62fd0d72 Mon Sep 17 00:00:00 2001
From: Andreas Schneider <asn@samba.org>
Date: Mon, 18 Mar 2019 15:13:08 +0100
Subject: [PATCH 091/187] libcli:auth: Use GnuTLS AES128 CFB for
 netlogon_creds_aes_decrypt()

Signed-off-by: Andreas Schneider <asn@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
(cherry picked from commit a96728586150768957b88a0714b15f13ee9f81af)
---
 libcli/auth/credentials.c | 41 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 40 insertions(+), 1 deletion(-)

diff --git a/libcli/auth/credentials.c b/libcli/auth/credentials.c
index 87f8820238e..cfeab6efdcd 100644
--- a/libcli/auth/credentials.c
+++ b/libcli/auth/credentials.c
@@ -22,10 +22,13 @@
 
 #include "includes.h"
 #include "system/time.h"
-#include "../lib/crypto/crypto.h"
 #include "libcli/auth/libcli_auth.h"
 #include "../libcli/security/dom_sid.h"
 
+#ifndef HAVE_GNUTLS_AES_CFB8
+#include "lib/crypto/aes.h"
+#endif
+
 #include "lib/crypto/gnutls_helpers.h"
 #include <gnutls/gnutls.h>
 #include <gnutls/crypto.h>
@@ -345,12 +348,48 @@ NTSTATUS netlogon_creds_aes_encrypt(struct netlogon_creds_CredentialState *creds
 */
 void netlogon_creds_aes_decrypt(struct netlogon_creds_CredentialState *creds, uint8_t *data, size_t len)
 {
+#ifdef HAVE_GNUTLS_AES_CFB8
+	gnutls_cipher_hd_t cipher_hnd = NULL;
+	gnutls_datum_t key = {
+		.data = creds->session_key,
+		.size = sizeof(creds->session_key),
+	};
+	uint32_t iv_size =
+		gnutls_cipher_get_iv_size(GNUTLS_CIPHER_AES_128_CFB8);
+	uint8_t _iv[iv_size];
+	gnutls_datum_t iv = {
+		.data = _iv,
+		.size = iv_size,
+	};
+	int rc;
+
+	ZERO_ARRAY(_iv);
+
+	rc = gnutls_cipher_init(&cipher_hnd,
+				GNUTLS_CIPHER_AES_128_CFB8,
+				&key,
+				&iv);
+	if (rc < 0) {
+		DBG_ERR("ERROR: gnutls_cipher_init: %s\n",
+			gnutls_strerror(rc));
+		return;
+	}
+
+	rc = gnutls_cipher_decrypt(cipher_hnd, data, len);
+	gnutls_cipher_deinit(cipher_hnd);
+	if (rc < 0) {
+		DBG_ERR("ERROR: gnutls_cipher_decrypt: %s\n",
+			gnutls_strerror(rc));
+		return;
+	}
+#else /* NOT HAVE_GNUTLS_AES_CFB8 */
 	AES_KEY key;
 	uint8_t iv[AES_BLOCK_SIZE] = {0};
 
 	AES_set_encrypt_key(creds->session_key, 128, &key);
 
 	aes_cfb8_encrypt(data, data, len, &key, iv, AES_DECRYPT);
+#endif /* HAVE_GNUTLS_AES_CFB8 */
 }
 
 /*****************************************************************
-- 
2.23.0