nettle: added HKDF functions

They are being included conditionally depending on the RSA-PSS feature
(RSA-PSS and HKDF are expected to be introduced at the same version).

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

3 files changed, 164 insertions, 0 deletions

diff --git a/lib/nettle/Makefile.am b/lib/nettle/Makefile.am
index 182d7d9838..4c044c9f9b 100644
--- a/lib/nettle/Makefile.am
+++ b/lib/nettle/Makefile.am
@@ -65,4 +65,8 @@ libcrypto_la_SOURCES += int/pss-mgf1.c int/pss-mgf1.h int/pss.c int/pss.h \
 	int/rsa-pss.c int/rsa-pss.h \
 	int/rsa-pss-sha256-sign-tr.c int/rsa-pss-sha256-verify.c \
 	int/rsa-pss-sha512-sign-tr.c int/rsa-pss-sha512-verify.c
+
+# HKDF was introduced in the same version of nettle
+libcrypto_la_SOURCES += int/hkdf.c int/hkdf.h
+
 endif
diff --git a/lib/nettle/int/hkdf.c b/lib/nettle/int/hkdf.c
new file mode 100644
index 0000000000..3ff6c24eb0
--- /dev/null
+++ b/lib/nettle/int/hkdf.c
@@ -0,0 +1,94 @@
+/* hkdf.c
+
+   HKDF key derivation function, see RFC 5869.
+
+   Copyright (C) 2017 Red Hat, Inc.
+
+   Author: Nikos Mavrogiannopoulos
+
+   This file is part of GNU Nettle.
+
+   GNU Nettle is free software: you can redistribute it and/or
+   modify it under the terms of either:
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at your
+       option) any later version.
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at your
+       option) any later version.
+
+   or both in parallel, as here.
+
+   GNU Nettle is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see http://www.gnu.org/licenses/.
+*/
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+/* Needed for alloca on freebsd */
+#include <stdlib.h>
+#include <string.h>
+
+#include <nettle/hmac.h>
+
+#include <nettle/memxor.h>
+#include "hkdf.h"
+
+/* hkdf_extract: Outputs a PRK of digest_size
+ */
+void
+hkdf_extract (void *mac_ctx,
+	      nettle_hash_update_func * update,
+	      nettle_hash_digest_func * digest,
+	      size_t digest_size,
+	      size_t secret_size, const uint8_t * secret, uint8_t * dst)
+{
+  update (mac_ctx, secret_size, secret);
+  digest (mac_ctx, digest_size, dst);
+}
+
+/* hkdf_expand: Outputs an arbitrary key of size specified by length
+ */
+void
+hkdf_expand (void *mac_ctx,
+	     nettle_hash_update_func * update,
+	     nettle_hash_digest_func * digest,
+	     size_t digest_size,
+	     size_t info_size, const uint8_t * info,
+	     size_t length, uint8_t * dst)
+{
+  uint8_t i = 1;
+  ssize_t left = length;
+
+  if (!left)
+    return;
+
+  for (;; dst += digest_size, left -= digest_size, i++)
+    {
+      update (mac_ctx, info_size, info);
+      update (mac_ctx, 1, &i);
+      if (left <= (ssize_t)digest_size)
+	{
+	  if (left > 0)
+	    digest (mac_ctx, left, dst);
+	  return;
+	}
+
+      digest (mac_ctx, digest_size, dst);
+      update (mac_ctx, digest_size, dst);
+    }
+
+  return;
+}
diff --git a/lib/nettle/int/hkdf.h b/lib/nettle/int/hkdf.h
new file mode 100644
index 0000000000..a7101da3a8
--- /dev/null
+++ b/lib/nettle/int/hkdf.h
@@ -0,0 +1,66 @@
+/* hkdf.h
+
+   HKDF key derivation function, see RFC 5869.
+
+   Copyright (C) 2017 Red Hat, Inc.
+
+   This file is part of GNU Nettle.
+
+   GNU Nettle is free software: you can redistribute it and/or
+   modify it under the terms of either:
+
+     * the GNU Lesser General Public License as published by the Free
+       Software Foundation; either version 3 of the License, or (at your
+       option) any later version.
+
+   or
+
+     * the GNU General Public License as published by the Free
+       Software Foundation; either version 2 of the License, or (at your
+       option) any later version.
+
+   or both in parallel, as here.
+
+   GNU Nettle is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received copies of the GNU General Public License and
+   the GNU Lesser General Public License along with this program.  If
+   not, see http://www.gnu.org/licenses/.
+*/
+
+#ifndef _HKDF_H_INCLUDED
+#define _HKDF_H_INCLUDED
+
+#include <nettle/nettle-meta.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Namespace mangling */
+#define hkdf_extract gnutls_hkdf_extract
+#define hkdf_expand gnutls_hkdf_expand
+
+	void
+	 hkdf_extract(void *mac_ctx,
+		      nettle_hash_update_func * update,
+		      nettle_hash_digest_func * digest,
+		      size_t digest_size,
+		      size_t secret_size, const uint8_t * secret,
+		      uint8_t * dst);
+
+	void
+	 hkdf_expand(void *mac_ctx,
+		     nettle_hash_update_func * update,
+		     nettle_hash_digest_func * digest,
+		     size_t digest_size,
+		     size_t info_size, const uint8_t * info,
+		     size_t length, uint8_t * dst);
+
+#ifdef __cplusplus
+}
+#endif
+#endif				/* NETTLE_HKDF_H_INCLUDED */