From a6a0788cbbe8dfce2819ee43b09c80725742e21c Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Fri, 7 Dec 2018 03:39:40 +0000 Subject: upstream: only consider the ext-info-c extension during the initial KEX. It shouldn't be sent in subsequent ones, but if it is present we should ignore it. This prevents sshd from sending a SSH_MSG_EXT_INFO for REKEX for buggy these clients. Reported by Jakub Jelen via bz2929; ok dtucker@ OpenBSD-Commit-ID: 91564118547f7807030ec537480303e2371902f9 --- kex.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'kex.c') diff --git a/kex.c b/kex.c index 25f9f66f6..3823a9544 100644 --- a/kex.c +++ b/kex.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kex.c,v 1.141 2018/07/09 13:37:10 sf Exp $ */ +/* $OpenBSD: kex.c,v 1.142 2018/12/07 03:39:40 djm Exp $ */ /* * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. * @@ -487,6 +487,7 @@ kex_input_newkeys(int type, u_int32_t seq, struct ssh *ssh) if ((r = ssh_set_newkeys(ssh, MODE_IN)) != 0) return r; kex->done = 1; + kex->flags &= ~KEX_INITIAL; sshbuf_reset(kex->peer); /* sshbuf_reset(kex->my); */ kex->flags &= ~KEX_INIT_SENT; @@ -594,6 +595,7 @@ kex_new(struct ssh *ssh, char *proposal[PROPOSAL_MAX], struct kex **kexp) if ((r = kex_prop2buf(kex->my, proposal)) != 0) goto out; kex->done = 0; + kex->flags = KEX_INITIAL; kex_reset_dispatch(ssh); ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, &kex_input_kexinit); r = 0; @@ -839,7 +841,7 @@ kex_choose_conf(struct ssh *ssh) } /* Check whether client supports ext_info_c */ - if (kex->server) { + if (kex->server && (kex->flags & KEX_INITIAL)) { char *ext; ext = match_list("ext-info-c", peer[PROPOSAL_KEX_ALGS], NULL); -- cgit v1.2.3