1 files changed, 83 insertions, 51 deletions

diff --git a/kexc25519s.c b/kexc25519s.c
index 2b8e8efa1..b2d2c858f 100644
--- a/kexc25519s.c
+++ b/kexc25519s.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexc25519s.c,v 1.4 2014/01/12 08:13:13 djm Exp $ */
+/* $OpenBSD: kexc25519s.c,v 1.8 2015/01/26 06:10:03 djm Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -30,97 +30,129 @@
 #include <string.h>
 #include <signal.h>
 
-#include "xmalloc.h"
-#include "buffer.h"
-#include "key.h"
+#include "sshkey.h"
 #include "cipher.h"
+#include "digest.h"
 #include "kex.h"
 #include "log.h"
 #include "packet.h"
 #include "ssh2.h"
+#include "sshbuf.h"
+#include "ssherr.h"
 
-void
-kexc25519_server(Kex *kex)
+static int input_kex_c25519_init(int, u_int32_t, void *);
+
+int
+kexc25519_server(struct ssh *ssh)
+{
+        debug("expecting SSH2_MSG_KEX_ECDH_INIT");
+        ssh_dispatch_set(ssh, SSH2_MSG_KEX_ECDH_INIT, &input_kex_c25519_init);
+        return 0;
+}
+
+static int
+input_kex_c25519_init(int type, u_int32_t seq, void *ctxt)
 {
-        Key *server_host_private, *server_host_public;
+        struct ssh *ssh = ctxt;
+        struct kex *kex = ssh->kex;
+        struct sshkey *server_host_private, *server_host_public;
+        struct sshbuf *shared_secret = NULL;
         u_char *server_host_key_blob = NULL, *signature = NULL;
         u_char server_key[CURVE25519_SIZE];
         u_char *client_pubkey = NULL;
         u_char server_pubkey[CURVE25519_SIZE];
-        u_char *hash;
-        u_int slen, sbloblen, hashlen;
-        Buffer shared_secret;
+        u_char hash[SSH_DIGEST_MAX_LENGTH];
+        size_t slen, pklen, sbloblen, hashlen;
+        int r;
 
         /* generate private key */
         kexc25519_keygen(server_key, server_pubkey);
 #ifdef DEBUG_KEXECDH
         dump_digest("server private key:", server_key, sizeof(server_key));
 #endif
-
         if (kex->load_host_public_key == NULL ||
-            kex->load_host_private_key == NULL)
-                fatal("Cannot load hostkey");
-        server_host_public = kex->load_host_public_key(kex->hostkey_type);
-        if (server_host_public == NULL)
-                fatal("Unsupported hostkey type %d", kex->hostkey_type);
-        server_host_private = kex->load_host_private_key(kex->hostkey_type);
-
-        debug("expecting SSH2_MSG_KEX_ECDH_INIT");
-        packet_read_expect(SSH2_MSG_KEX_ECDH_INIT);
-        client_pubkey = packet_get_string(&slen);
-        if (slen != CURVE25519_SIZE)
-                fatal("Incorrect size for server Curve25519 pubkey: %d", slen);
-        packet_check_eom();
+            kex->load_host_private_key == NULL) {
+                r = SSH_ERR_INVALID_ARGUMENT;
+                goto out;
+        }
+        server_host_public = kex->load_host_public_key(kex->hostkey_type,
+            kex->hostkey_nid, ssh);
+        server_host_private = kex->load_host_private_key(kex->hostkey_type,
+            kex->hostkey_nid, ssh);
+        if (server_host_public == NULL) {
+                r = SSH_ERR_NO_HOSTKEY_LOADED;
+                goto out;
+        }
 
+        if ((r = sshpkt_get_string(ssh, &client_pubkey, &pklen)) != 0 ||
+            (r = sshpkt_get_end(ssh)) != 0)
+                goto out;
+        if (pklen != CURVE25519_SIZE) {
+                r = SSH_ERR_SIGNATURE_INVALID;
+                goto out;
+        }
 #ifdef DEBUG_KEXECDH
         dump_digest("client public key:", client_pubkey, CURVE25519_SIZE);
 #endif
 
-        buffer_init(&shared_secret);
-        kexc25519_shared_key(server_key, client_pubkey, &shared_secret);
+        if ((shared_secret = sshbuf_new()) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if ((r = kexc25519_shared_key(server_key, client_pubkey,
+            shared_secret)) < 0)
+                goto out;
 
         /* calc H */
-        key_to_blob(server_host_public, &server_host_key_blob, &sbloblen);
-        kex_c25519_hash(
+        if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
+            &sbloblen)) != 0)
+                goto out;
+        hashlen = sizeof(hash);
+        if ((r = kex_c25519_hash(
             kex->hash_alg,
             kex->client_version_string,
             kex->server_version_string,
-            buffer_ptr(&kex->peer), buffer_len(&kex->peer),
-            buffer_ptr(&kex->my), buffer_len(&kex->my),
+            sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
+            sshbuf_ptr(kex->my), sshbuf_len(kex->my),
             server_host_key_blob, sbloblen,
             client_pubkey,
             server_pubkey,
-            buffer_ptr(&shared_secret), buffer_len(&shared_secret),
-            &hash, &hashlen
-        );
+            sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
+            hash, &hashlen)) < 0)
+                goto out;
 
         /* save session id := H */
         if (kex->session_id == NULL) {
                 kex->session_id_len = hashlen;
-                kex->session_id = xmalloc(kex->session_id_len);
+                kex->session_id = malloc(kex->session_id_len);
+                if (kex->session_id == NULL) {
+                        r = SSH_ERR_ALLOC_FAIL;
+                        goto out;
+                }
                 memcpy(kex->session_id, hash, kex->session_id_len);
         }
 
         /* sign H */
-        kex->sign(server_host_private, server_host_public, &signature, &slen,
-            hash, hashlen);
-
-        /* destroy_sensitive_data(); */
+        if ((r = kex->sign(server_host_private, server_host_public,
+            &signature, &slen, hash, hashlen, ssh->compat)) < 0)
+                goto out;
 
         /* send server hostkey, ECDH pubkey 'Q_S' and signed H */
-        packet_start(SSH2_MSG_KEX_ECDH_REPLY);
-        packet_put_string(server_host_key_blob, sbloblen);
-        packet_put_string(server_pubkey, sizeof(server_pubkey));
-        packet_put_string(signature, slen);
-        packet_send();
-
-        free(signature);
+        if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_REPLY)) != 0 ||
+            (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
+            (r = sshpkt_put_string(ssh, server_pubkey, sizeof(server_pubkey))) != 0 ||
+            (r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
+            (r = sshpkt_send(ssh)) != 0)
+                goto out;
+
+        if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
+                r = kex_send_newkeys(ssh);
+out:
+        explicit_bzero(hash, sizeof(hash));
+        explicit_bzero(server_key, sizeof(server_key));
         free(server_host_key_blob);
-        /* have keys, free server key */
+        free(signature);
         free(client_pubkey);
-
-        kex_derive_keys(kex, hash, hashlen,
-            buffer_ptr(&shared_secret), buffer_len(&shared_secret));
-        buffer_free(&shared_secret);
-        kex_finish(kex);
+        sshbuf_free(shared_secret);
+        return r;
 }