X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fopenssl%2Fprf.c;h=4f5a52befc65a98bbaf8338aa7dda5d4fe2a3d11;hb=390d25f0b80dd7418e147de3561c70461628574d;hp=2830d609a0c5cb2bba35ef3d5405f314a79a3efd;hpb=feb3f22fffa2620b9b11a509ce51ff9fa3be9418;p=tinc

diff --git a/src/openssl/prf.c b/src/openssl/prf.c
index 2830d609..4f5a52be 100644
--- a/src/openssl/prf.c
+++ b/src/openssl/prf.c
@@ -1,6 +1,6 @@
 /*
     prf.c -- Pseudo-Random Function for key material generation
-    Copyright (C) 2011 Guus Sliepen <guus@tinc-vpn.org>
+    Copyright (C) 2011-2013 Guus Sliepen <guus@tinc-vpn.org>
 
     This program is free software; you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -17,25 +17,30 @@
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
-#include "system.h"
+#include "../system.h"
+
+#include <openssl/obj_mac.h>
 
 #include "digest.h"
-#include "prf.h"
+#include "../digest.h"
+#include "../prf.h"
 
-/* Generate key material from a master secret and a seed, based on RFC 2246.
-   We use SHA512 and Whirlpool instead of MD5 and SHA1.
+/* Generate key material from a master secret and a seed, based on RFC 4346 section 5.
+   We use SHA512 instead of MD5 and SHA1.
  */
 
-static bool prf_xor(int nid, char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, ssize_t outlen) {
-	digest_t digest;
-	
-	if(!digest_open_by_nid(&digest, nid, 0))
+static bool prf_xor(int nid, const char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, ssize_t outlen) {
+	digest_t *digest = digest_open_by_nid(nid, -1);
+
+	if(!digest)
 		return false;
 
-	if(!digest_set_key(&digest, secret, secretlen))
+	if(!digest_set_key(digest, secret, secretlen)) {
+		digest_close(digest);
 		return false;
+	}
 
-	size_t len = digest_length(&digest);
+	size_t len = digest_length(digest);
 
 	/* Data is what the "inner" HMAC function processes.
 	   It consists of the previous HMAC result plus the seed.
@@ -49,10 +54,16 @@ static bool prf_xor(int nid, char *secret, size_t secretlen, char *seed, size_t
 
 	while(outlen > 0) {
 		/* Inner HMAC */
-		digest_create(&digest, data, len + seedlen, data);
+		if(!digest_create(digest, data, len + seedlen, data)) {
+			digest_close(digest);
+			return false;
+		}
 
 		/* Outer HMAC */
-		digest_create(&digest, data, len + seedlen, hash);
+		if(!digest_create(digest, data, len + seedlen, hash)) {
+			digest_close(digest);
+			return false;
+		}
 
 		/* XOR the results of the outer HMAC into the out buffer */
 		for(int i = 0; i < len && i < outlen; i++)
@@ -61,16 +72,13 @@ static bool prf_xor(int nid, char *secret, size_t secretlen, char *seed, size_t
 		outlen -= len;
 	}
 
-	digest_close(&digest);
+	digest_close(digest);
 	return true;
 }
 
-bool prf(char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, size_t outlen) {
-	/* Split secret in half, generate outlen bits with two different hash algorithms,
-	   and XOR the results. */
-
+bool prf(const char *secret, size_t secretlen, char *seed, size_t seedlen, char *out, size_t outlen) {
+	/* This construction allows us to easily switch back to a scheme where the PRF is calculated using two different digest algorithms. */
 	memset(out, 0, outlen);
 
-	return prf_xor(NID_sha512, secret, secretlen / 2, seed, seedlen, out, outlen)
-		&& prf_xor(NID_whirlpool, secret, secretlen / 2, seed, seedlen, out, outlen);
+	return prf_xor(NID_sha512, secret, secretlen, seed, seedlen, out, outlen);
 }