upstream commit

adapt kex to sshbuf and struct ssh; ok djm@

1 files changed, 99 insertions, 60 deletions

diff --git a/kexc25519c.c b/kexc25519c.c
index ffb537ef6..833ce0544 100644
--- a/kexc25519c.c
+++ b/kexc25519c.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexc25519c.c,v 1.5 2015/01/19 19:52:16 markus Exp $ */
+/* $OpenBSD: kexc25519c.c,v 1.6 2015/01/19 20:16:15 markus Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -33,97 +33,136 @@
 #include <string.h>
 #include <signal.h>
 
-#include "xmalloc.h"
-#include "buffer.h"
-#include "key.h"
+#include "sshkey.h"
 #include "cipher.h"
 #include "kex.h"
 #include "log.h"
 #include "packet.h"
 #include "ssh2.h"
+#include "sshbuf.h"
+#include "digest.h"
+#include "ssherr.h"
 
-void
-kexc25519_client(Kex *kex)
-{
-        Key *server_host_key;
-        u_char client_key[CURVE25519_SIZE];
-        u_char client_pubkey[CURVE25519_SIZE];
-        u_char *server_pubkey = NULL;
-        u_char *server_host_key_blob = NULL, *signature = NULL;
-        u_char *hash;
-        u_int slen, sbloblen, hashlen;
-        Buffer shared_secret;
-
-        kexc25519_keygen(client_key, client_pubkey);
+static int
+input_kex_c25519_reply(int type, u_int32_t seq, void *ctxt);
 
-        packet_start(SSH2_MSG_KEX_ECDH_INIT);
-        packet_put_string(client_pubkey, sizeof(client_pubkey));
-        packet_send();
-        debug("sending SSH2_MSG_KEX_ECDH_INIT");
+int
+kexc25519_client(struct ssh *ssh)
+{
+        struct kex *kex = ssh->kex;
+        int r;
 
+        kexc25519_keygen(kex->c25519_client_key, kex->c25519_client_pubkey);
 #ifdef DEBUG_KEXECDH
-        dump_digest("client private key:", client_key, sizeof(client_key));
+        dump_digest("client private key:", kex->c25519_client_key,
+            sizeof(kex->c25519_client_key));
 #endif
+        if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_INIT)) != 0 ||
+            (r = sshpkt_put_string(ssh, kex->c25519_client_pubkey,
+            sizeof(kex->c25519_client_pubkey))) != 0 ||
+            (r = sshpkt_send(ssh)) != 0)
+                return r;
 
         debug("expecting SSH2_MSG_KEX_ECDH_REPLY");
-        packet_read_expect(SSH2_MSG_KEX_ECDH_REPLY);
+        ssh_dispatch_set(ssh, SSH2_MSG_KEX_ECDH_REPLY, &input_kex_c25519_reply);
+        return 0;
+}
+
+static int
+input_kex_c25519_reply(int type, u_int32_t seq, void *ctxt)
+{
+        struct ssh *ssh = ctxt;
+        struct kex *kex = ssh->kex;
+        struct sshkey *server_host_key = NULL;
+        struct sshbuf *shared_secret = NULL;
+        u_char *server_pubkey = NULL;
+        u_char *server_host_key_blob = NULL, *signature = NULL;
+        u_char hash[SSH_DIGEST_MAX_LENGTH];
+        size_t slen, pklen, sbloblen, hashlen;
+        int r;
+
+        if (kex->verify_host_key == NULL) {
+                r = SSH_ERR_INVALID_ARGUMENT;
+                goto out;
+        }
 
         /* hostkey */
-        server_host_key_blob = packet_get_string(&sbloblen);
-        server_host_key = key_from_blob(server_host_key_blob, sbloblen);
-        if (server_host_key == NULL)
-                fatal("cannot decode server_host_key_blob");
-        if (server_host_key->type != kex->hostkey_type)
-                fatal("type mismatch for decoded server_host_key_blob");
-        if (kex->verify_host_key == NULL)
-                fatal("cannot verify server_host_key");
-        if (kex->verify_host_key(server_host_key) == -1)
-                fatal("server_host_key verification failed");
+        if ((r = sshpkt_get_string(ssh, &server_host_key_blob,
+            &sbloblen)) != 0 ||
+            (r = sshkey_from_blob(server_host_key_blob, sbloblen,
+            &server_host_key)) != 0)
+                goto out;
+        if (server_host_key->type != kex->hostkey_type) {
+                r = SSH_ERR_KEY_TYPE_MISMATCH;
+                goto out;
+        }
+        if (kex->verify_host_key(server_host_key, ssh) == -1) {
+                r = SSH_ERR_SIGNATURE_INVALID;
+                goto out;
+        }
 
         /* Q_S, server public key */
-        server_pubkey = packet_get_string(&slen);
-        if (slen != CURVE25519_SIZE)
-                fatal("Incorrect size for server Curve25519 pubkey: %d", slen);
+        /* signed H */
+        if ((r = sshpkt_get_string(ssh, &server_pubkey, &pklen)) != 0 ||
+            (r = sshpkt_get_string(ssh, &signature, &slen)) != 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("server public key:", server_pubkey, CURVE25519_SIZE);
 #endif
 
-        /* signed H */
-        signature = packet_get_string(&slen);
-        packet_check_eom();
-
-        buffer_init(&shared_secret);
-        kexc25519_shared_key(client_key, server_pubkey, &shared_secret);
+        if ((shared_secret = sshbuf_new()) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if ((r = kexc25519_shared_key(kex->c25519_client_key, server_pubkey,
+            shared_secret)) < 0)
+                goto out;
 
         /* calc and verify H */
-        kex_c25519_hash(
+        hashlen = sizeof(hash);
+        if ((r = kex_c25519_hash(
             kex->hash_alg,
             kex->client_version_string,
             kex->server_version_string,
-            buffer_ptr(kex->my), buffer_len(kex->my),
-            buffer_ptr(kex->peer), buffer_len(kex->peer),
+            sshbuf_ptr(kex->my), sshbuf_len(kex->my),
+            sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
             server_host_key_blob, sbloblen,
-            client_pubkey,
+            kex->c25519_client_pubkey,
             server_pubkey,
-            buffer_ptr(&shared_secret), buffer_len(&shared_secret),
-            &hash, &hashlen
-        );
-        free(server_host_key_blob);
-        free(server_pubkey);
-        if (key_verify(server_host_key, signature, slen, hash, hashlen) != 1)
-                fatal("key_verify failed for server_host_key");
-        key_free(server_host_key);
-        free(signature);
+            sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
+            hash, &hashlen)) < 0)
+                goto out;
+
+        if ((r = sshkey_verify(server_host_key, signature, slen, hash, hashlen,
+            ssh->compat)) != 0)
+                goto out;
 
         /* save session id */
         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);
         }
-        kex_derive_keys(kex, hash, hashlen,
-            buffer_ptr(&shared_secret), buffer_len(&shared_secret));
-        buffer_free(&shared_secret);
-        kex_finish(kex);
+
+        if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
+                r = kex_send_newkeys(ssh);
+out:
+        explicit_bzero(hash, sizeof(hash));
+        explicit_bzero(kex->c25519_client_key, sizeof(kex->c25519_client_key));
+        free(server_host_key_blob);
+        free(server_pubkey);
+        free(signature);
+        sshkey_free(server_host_key);
+        sshbuf_free(shared_secret);
+        return r;
 }