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