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
diff --git a/kex.c b/kex.c
index 25f9f66..3823a95 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 @@
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 @@
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 @@
}
/* 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);
diff --git a/kex.h b/kex.h
index 593de12..0f67f58 100644
--- a/kex.h
+++ b/kex.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.h,v 1.91 2018/07/11 18:53:29 markus Exp $ */
+/* $OpenBSD: kex.h,v 1.92 2018/12/07 03:39:40 djm Exp $ */
/*
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
@@ -104,6 +104,7 @@
};
#define KEX_INIT_SENT 0x0001
+#define KEX_INITIAL 0x0002
struct sshenc {
char *name;