upstream: move client/server SSH-* banners to buffers under

ssh->kex and factor out the banner exchange. This eliminates some common code
from the client and server.

Also be more strict about handling \r characters - these should only
be accepted immediately before \n (pointed out by Jann Horn).

Inspired by a patch from Markus Schmidt.
(lots of) feedback and ok markus@

OpenBSD-Commit-ID: 1cc7885487a6754f63641d7d3279b0941890275b

1 files changed, 12 insertions, 8 deletions

diff --git a/kex.h b/kex.h
index 0f67f58db..9ba860954 100644
--- a/kex.h
+++ b/kex.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.h,v 1.92 2018/12/07 03:39:40 djm Exp $ */
+/* $OpenBSD: kex.h,v 1.93 2018/12/27 03:25:25 djm Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -145,12 +145,12 @@ struct kex {
         int     ext_info_c;
         struct sshbuf *my;
         struct sshbuf *peer;
+        struct sshbuf *client_version;
+        struct sshbuf *server_version;
         sig_atomic_t done;
         u_int   flags;
         int     hash_alg;
         int     ec_nid;
-        char    *client_version_string;
-        char    *server_version_string;
         char    *failed_choice;
         int     (*verify_host_key)(struct sshkey *, struct ssh *);
         struct sshkey *(*load_host_public_key)(int, int, struct ssh *);
@@ -173,7 +173,10 @@ char	*kex_alg_list(char);
 char    *kex_names_cat(const char *, const char *);
 int      kex_assemble_names(char **, const char *, const char *);
 
-int      kex_new(struct ssh *, char *[PROPOSAL_MAX], struct kex **);
+int      kex_exchange_identification(struct ssh *, int, const char *);
+
+struct kex *kex_new(void);
+int      kex_ready(struct ssh *, char *[PROPOSAL_MAX]);
 int      kex_setup(struct ssh *, char *[PROPOSAL_MAX]);
 void     kex_free_newkeys(struct newkeys *);
 void     kex_free(struct kex *);
@@ -199,22 +202,23 @@ int	 kexecdh_server(struct ssh *);
 int      kexc25519_client(struct ssh *);
 int      kexc25519_server(struct ssh *);
 
-int      kex_dh_hash(int, const char *, const char *,
+int      kex_dh_hash(int, const struct sshbuf *, const struct sshbuf *,
     const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
     const BIGNUM *, const BIGNUM *, const BIGNUM *, u_char *, size_t *);
 
-int      kexgex_hash(int, const char *, const char *,
+int      kexgex_hash(int, const struct sshbuf *, const struct sshbuf *,
     const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
     int, int, int,
     const BIGNUM *, const BIGNUM *, const BIGNUM *,
     const BIGNUM *, const BIGNUM *,
     u_char *, size_t *);
 
-int kex_ecdh_hash(int, const EC_GROUP *, const char *, const char *,
+int kex_ecdh_hash(int, const EC_GROUP *,
+    const struct sshbuf *, const struct sshbuf *,
     const u_char *, size_t, const u_char *, size_t, const u_char *, size_t,
     const EC_POINT *, const EC_POINT *, const BIGNUM *, u_char *, size_t *);
 
-int      kex_c25519_hash(int, const char *, const char *,
+int      kex_c25519_hash(int, const struct sshbuf *, const struct sshbuf *,
     const u_char *, size_t, const u_char *, size_t,
     const u_char *, size_t, const u_char *, const u_char *,
     const u_char *, size_t, u_char *, size_t *);