upstream: factor out DH keygen; it's identical between the client

and the server

from markus@ ok djm@

OpenBSD-Commit-ID: 2be57f6a0d44f1ab2c8de2b1b5d6f530c387fae9

1 files changed, 27 insertions, 1 deletions

diff --git a/kexdh.c b/kexdh.c
index 34c55ef9f..916036994 100644
--- a/kexdh.c
+++ b/kexdh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexdh.c,v 1.27 2018/12/27 03:25:25 djm Exp $ */
+/* $OpenBSD: kexdh.c,v 1.28 2019/01/21 10:00:23 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -39,11 +39,37 @@
 #include "sshkey.h"
 #include "cipher.h"
 #include "kex.h"
+#include "dh.h"
 #include "ssherr.h"
 #include "sshbuf.h"
 #include "digest.h"
 
 int
+kex_dh_keygen(struct kex *kex)
+{
+        switch (kex->kex_type) {
+        case KEX_DH_GRP1_SHA1:
+                kex->dh = dh_new_group1();
+                break;
+        case KEX_DH_GRP14_SHA1:
+        case KEX_DH_GRP14_SHA256:
+                kex->dh = dh_new_group14();
+                break;
+        case KEX_DH_GRP16_SHA512:
+                kex->dh = dh_new_group16();
+                break;
+        case KEX_DH_GRP18_SHA512:
+                kex->dh = dh_new_group18();
+                break;
+        default:
+                return SSH_ERR_INVALID_ARGUMENT;
+        }
+        if (kex->dh == NULL)
+                return SSH_ERR_ALLOC_FAIL;
+        return (dh_gen_key(kex->dh, kex->we_need * 8));
+}
+
+int
 kex_dh_hash(
     int hash_alg,
     const struct sshbuf *client_version,