diff -U0 openssh-6.2p2/ChangeLog.dh openssh-6.2p2/ChangeLog
--- openssh-6.2p2/ChangeLog.dh 2013-11-18 12:14:09.662240103 +0100
+++ openssh-6.2p2/ChangeLog 2013-11-18 12:14:09.665240089 +0100
@@ -0,0 +1,8 @@
+20131010
+ - dtucker@cvs.openbsd.org 2013/10/08 11:42:13
+ [dh.c dh.h]
+ Increase the size of the Diffie-Hellman groups requested for a each
+ symmetric key size. New values from NIST Special Publication 800-57 with
+ the upper limit specified by RFC4419. Pointed out by Peter Backes, ok
+ djm@.
+
diff -up openssh-6.2p2/dh.c.dh openssh-6.2p2/dh.c
--- openssh-6.2p2/dh.c.dh 2011-12-19 00:52:52.000000000 +0100
+++ openssh-6.2p2/dh.c 2013-11-18 12:14:09.665240089 +0100
@@ -332,17 +332,20 @@ dh_new_group14(void)
/*
* Estimates the group order for a Diffie-Hellman group that has an
- * attack complexity approximately the same as O(2**bits). Estimate
- * with: O(exp(1.9223 * (ln q)^(1/3) (ln ln q)^(2/3)))
+ * attack complexity approximately the same as O(2**bits).
+ * Values from NIST Special Publication 800-57: Recommendation for Key
+ * Management Part 1 (rev 3) limited by the recommended maximum value
+ * from RFC4419 section 3.
*/
int
dh_estimate(int bits)
{
-
+ if (bits <= 112)
+ return 2048;
if (bits <= 128)
- return (1024); /* O(2**86) */
+ return 3072;
if (bits <= 192)
- return (2048); /* O(2**116) */
- return (4096); /* O(2**156) */
+ return 7680;
+ return 8192;
}
diff -up openssh-6.2p2/dh.h.dh openssh-6.2p2/dh.h
--- openssh-6.2p2/dh.h.dh 2008-06-29 14:47:04.000000000 +0200
+++ openssh-6.2p2/dh.h 2013-11-18 12:14:09.665240089 +0100
@@ -1,4 +1,4 @@
-/* $OpenBSD: dh.h,v 1.10 2008/06/26 09:19:40 djm Exp $ */
+/* $OpenBSD: dh.h,v 1.11 2013/10/08 11:42:13 dtucker Exp $ */
/*
* Copyright (c) 2000 Niels Provos. All rights reserved.
@@ -43,6 +43,7 @@ int dh_pub_is_valid(DH *, BIGNUM *);
int dh_estimate(int);
+/* Min and max values from RFC4419. */
#define DH_GRP_MIN 1024
#define DH_GRP_MAX 8192