upstream commit

adapt kex to sshbuf and struct ssh; ok djm@

1 files changed, 137 insertions, 70 deletions

diff --git a/kexecdhc.c b/kexecdhc.c
index df811c1c8..3f362c5b1 100644
--- a/kexecdhc.c
+++ b/kexecdhc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexecdhc.c,v 1.8 2015/01/19 19:52:16 markus Exp $ */
+/* $OpenBSD: kexecdhc.c,v 1.9 2015/01/19 20:16:15 markus Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2010 Damien Miller.  All rights reserved.
@@ -34,126 +34,193 @@
 #include <string.h>
 #include <signal.h>
 
-#include "xmalloc.h"
-#include "buffer.h"
-#include "key.h"
+#include <openssl/ecdh.h>
+
+#include "sshkey.h"
 #include "cipher.h"
+#include "digest.h"
 #include "kex.h"
 #include "log.h"
 #include "packet.h"
 #include "dh.h"
 #include "ssh2.h"
+#include "dispatch.h"
+#include "compat.h"
+#include "ssherr.h"
+#include "sshbuf.h"
 
-#include <openssl/ecdh.h>
+static int input_kex_ecdh_reply(int, u_int32_t, void *);
 
-void
-kexecdh_client(Kex *kex)
+int
+kexecdh_client(struct ssh *ssh)
 {
-        EC_KEY *client_key;
-        EC_POINT *server_public;
+        struct kex *kex = ssh->kex;
+        EC_KEY *client_key = NULL;
         const EC_GROUP *group;
-        BIGNUM *shared_secret;
-        Key *server_host_key;
-        u_char *server_host_key_blob = NULL, *signature = NULL;
-        u_char *kbuf, *hash;
-        u_int klen, slen, sbloblen, hashlen;
+        const EC_POINT *public_key;
+        int r;
 
-        if ((client_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL)
-                fatal("%s: EC_KEY_new_by_curve_name failed", __func__);
-        if (EC_KEY_generate_key(client_key) != 1)
-                fatal("%s: EC_KEY_generate_key failed", __func__);
+        if ((client_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if (EC_KEY_generate_key(client_key) != 1) {
+                r = SSH_ERR_LIBCRYPTO_ERROR;
+                goto out;
+        }
         group = EC_KEY_get0_group(client_key);
+        public_key = EC_KEY_get0_public_key(client_key);
 
-        packet_start(SSH2_MSG_KEX_ECDH_INIT);
-        packet_put_ecpoint(group, EC_KEY_get0_public_key(client_key));
-        packet_send();
+        if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_INIT)) != 0 ||
+            (r = sshpkt_put_ec(ssh, public_key, group)) != 0 ||
+            (r = sshpkt_send(ssh)) != 0)
+                goto out;
         debug("sending SSH2_MSG_KEX_ECDH_INIT");
 
 #ifdef DEBUG_KEXECDH
         fputs("client private key:\n", stderr);
-        key_dump_ec_key(client_key);
+        sshkey_dump_ec_key(client_key);
 #endif
+        kex->ec_client_key = client_key;
+        kex->ec_group = group;
+        client_key = NULL;      /* owned by the kex */
 
         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_ecdh_reply);
+        r = 0;
+ out:
+        if (client_key)
+                EC_KEY_free(client_key);
+        return r;
+}
+
+static int
+input_kex_ecdh_reply(int type, u_int32_t seq, void *ctxt)
+{
+        struct ssh *ssh = ctxt;
+        struct kex *kex = ssh->kex;
+        const EC_GROUP *group;
+        EC_POINT *server_public = NULL;
+        EC_KEY *client_key;
+        BIGNUM *shared_secret = NULL;
+        struct sshkey *server_host_key = NULL;
+        u_char *server_host_key_blob = NULL, *signature = NULL;
+        u_char *kbuf = NULL;
+        u_char hash[SSH_DIGEST_MAX_LENGTH];
+        size_t slen, sbloblen;
+        size_t klen = 0, hashlen;
+        int r;
+
+        if (kex->verify_host_key == NULL) {
+                r = SSH_ERR_INVALID_ARGUMENT;
+                goto out;
+        }
+        group = kex->ec_group;
+        client_key = kex->ec_client_key;
 
         /* 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 */
-        if ((server_public = EC_POINT_new(group)) == NULL)
-                fatal("%s: EC_POINT_new failed", __func__);
-        packet_get_ecpoint(group, server_public);
-
-        if (key_ec_validate_public(group, server_public) != 0)
-                fatal("%s: invalid server public key", __func__);
+        /* signed H */
+        if ((server_public = EC_POINT_new(group)) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
+        if ((r = sshpkt_get_ec(ssh, server_public, group)) != 0 ||
+            (r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
+            (r = sshpkt_get_end(ssh)) != 0)
+                goto out;
 
 #ifdef DEBUG_KEXECDH
         fputs("server public key:\n", stderr);
-        key_dump_ec_point(group, server_public);
+        sshkey_dump_ec_point(group, server_public);
 #endif
-
-        /* signed H */
-        signature = packet_get_string(&slen);
-        packet_check_eom();
+        if (sshkey_ec_validate_public(group, server_public) != 0) {
+                sshpkt_disconnect(ssh, "invalid server public key");
+                r = SSH_ERR_MESSAGE_INCOMPLETE;
+                goto out;
+        }
 
         klen = (EC_GROUP_get_degree(group) + 7) / 8;
-        kbuf = xmalloc(klen);
+        if ((kbuf = malloc(klen)) == NULL ||
+            (shared_secret = BN_new()) == NULL) {
+                r = SSH_ERR_ALLOC_FAIL;
+                goto out;
+        }
         if (ECDH_compute_key(kbuf, klen, server_public,
-            client_key, NULL) != (int)klen)
-                fatal("%s: ECDH_compute_key failed", __func__);
+            client_key, NULL) != (int)klen ||
+            BN_bin2bn(kbuf, klen, shared_secret) == NULL) {
+                r = SSH_ERR_LIBCRYPTO_ERROR;
+                goto out;
+        }
 
 #ifdef DEBUG_KEXECDH
         dump_digest("shared secret", kbuf, klen);
 #endif
-        if ((shared_secret = BN_new()) == NULL)
-                fatal("%s: BN_new failed", __func__);
-        if (BN_bin2bn(kbuf, klen, shared_secret) == NULL)
-                fatal("%s: BN_bin2bn failed", __func__);
-        explicit_bzero(kbuf, klen);
-        free(kbuf);
-
         /* calc and verify H */
-        kex_ecdh_hash(
+        hashlen = sizeof(hash);
+        if ((r = kex_ecdh_hash(
             kex->hash_alg,
             group,
             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,
             EC_KEY_get0_public_key(client_key),
             server_public,
             shared_secret,
-            &hash, &hashlen
-        );
-        free(server_host_key_blob);
-        EC_POINT_clear_free(server_public);
-        EC_KEY_free(client_key);
+            hash, &hashlen)) != 0)
+                goto out;
 
-        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);
+        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_bn(kex, hash, hashlen, shared_secret);
-        BN_clear_free(shared_secret);
-        kex_finish(kex);
+        if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
+                r = kex_send_newkeys(ssh);
+ out:
+        explicit_bzero(hash, sizeof(hash));
+        if (kex->ec_client_key) {
+                EC_KEY_free(kex->ec_client_key);
+                kex->ec_client_key = NULL;
+        }
+        if (server_public)
+                EC_POINT_clear_free(server_public);
+        if (kbuf) {
+                explicit_bzero(kbuf, klen);
+                free(kbuf);
+        }
+        if (shared_secret)
+                BN_clear_free(shared_secret);
+        sshkey_free(server_host_key);
+        free(server_host_key_blob);
+        free(signature);
+        return r;
 }
 #endif /* defined(WITH_OPENSSL) && defined(OPENSSL_HAS_ECC) */
+