From 4ba0d54794814ec0de1ec87987d0c3b89379b436 Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Tue, 3 Jul 2018 11:39:54 +0000 Subject: upstream: Improve strictness and control over RSA-SHA2 signature In ssh, when an agent fails to return a RSA-SHA2 signature when requested and falls back to RSA-SHA1 instead, retry the signature to ensure that the public key algorithm sent in the SSH_MSG_USERAUTH matches the one in the signature itself. In sshd, strictly enforce that the public key algorithm sent in the SSH_MSG_USERAUTH message matches what appears in the signature. Make the sshd_config PubkeyAcceptedKeyTypes and HostbasedAcceptedKeyTypes options control accepted signature algorithms (previously they selected supported key types). This allows these options to ban RSA-SHA1 in favour of RSA-SHA2. Add new signature algorithms "rsa-sha2-256-cert-v01@openssh.com" and "rsa-sha2-512-cert-v01@openssh.com" to force use of RSA-SHA2 signatures with certificate keys. feedback and ok markus@ OpenBSD-Commit-ID: c6e9f6d45eed8962ad502d315d7eaef32c419dde --- compat.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-) (limited to 'compat.c') diff --git a/compat.c b/compat.c index 1c0e0873..1c9890aa 100644 --- a/compat.c +++ b/compat.c @@ -1,4 +1,4 @@ -/* $OpenBSD: compat.c,v 1.107 2018/04/16 22:50:44 djm Exp $ */ +/* $OpenBSD: compat.c,v 1.108 2018/07/03 11:39:54 djm Exp $ */ /* * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. * @@ -52,16 +52,27 @@ compat_datafellows(const char *version) } check[] = { { "OpenSSH_2.*," "OpenSSH_3.0*," - "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, - { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR }, - { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF}, + "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR| + SSH_BUG_SIGTYPE}, + { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE }, + { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| + SSH_BUG_SIGTYPE}, { "OpenSSH_2*," "OpenSSH_3*," - "OpenSSH_4*", 0 }, - { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT}, - { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH}, + "OpenSSH_4*", SSH_BUG_SIGTYPE }, + { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT| + SSH_BUG_SIGTYPE}, + { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, { "OpenSSH_6.5*," - "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD}, + "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD| + SSH_BUG_SIGTYPE}, + { "OpenSSH_7.0*," + "OpenSSH_7.1*," + "OpenSSH_7.2*," + "OpenSSH_7.3*," + "OpenSSH_7.4*," + "OpenSSH_7.5*," + "OpenSSH_7.6*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, { "OpenSSH*", SSH_NEW_OPENSSH }, { "*MindTerm*", 0 }, { "3.0.*", SSH_BUG_DEBUG }, -- cgit v1.2.1