adapt kex to sshbuf and struct ssh; ok djm@

1 files changed, 119 insertions, 67 deletions

diff --git a/usr.bin/ssh/kexdhs.c b/usr.bin/ssh/kexdhs.c
index 121134c44ed..1ac5a4e16d1 100644
--- a/usr.bin/ssh/kexdhs.c
+++ b/usr.bin/ssh/kexdhs.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexdhs.c,v 1.19 2015/01/19 19:52:16 markus Exp $ */
+/* $OpenBSD: kexdhs.c,v 1.20 2015/01/19 20:16:15 markus Exp $ */
 /*
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
  *
@@ -30,55 +30,88 @@
 
 #include <openssl/dh.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 "dh.h"
 #include "ssh2.h"
 
-void
-kexdh_server(Kex *kex)
+#include "dispatch.h"
+#include "compat.h"
+#include "ssherr.h"
+#include "sshbuf.h"
+
+static int input_kex_dh_init(int, u_int32_t, void *);
+
+int
+kexdh_server(struct ssh *ssh)
 {
-	BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
-	DH *dh;
-	Key *server_host_public, *server_host_private;
-	u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
-	u_int sbloblen, klen, hashlen, slen;
-	int kout;
+	struct kex *kex = ssh->kex;
+	int r;
 
 	/* generate server DH public key */
 	switch (kex->kex_type) {
 	case KEX_DH_GRP1_SHA1:
-		dh = dh_new_group1();
+		kex->dh = dh_new_group1();
 		break;
 	case KEX_DH_GRP14_SHA1:
-		dh = dh_new_group14();
+		kex->dh = dh_new_group14();
 		break;
 	default:
-		fatal("%s: Unexpected KEX type %d", __func__, kex->kex_type);
+		r = SSH_ERR_INVALID_ARGUMENT;
+		goto out;
 	}
-	dh_gen_key(dh, kex->we_need * 8);
+	if (kex->dh == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
+		goto out;
 
 	debug("expecting SSH2_MSG_KEXDH_INIT");
-	packet_read_expect(SSH2_MSG_KEXDH_INIT);
+	ssh_dispatch_set(ssh, SSH2_MSG_KEXDH_INIT, &input_kex_dh_init);
+	r = 0;
+ out:
+	return r;
+}
+
+int
+input_kex_dh_init(int type, u_int32_t seq, void *ctxt)
+{
+	struct ssh *ssh = ctxt;
+	struct kex *kex = ssh->kex;
+	BIGNUM *shared_secret = NULL, *dh_client_pub = NULL;
+	struct sshkey *server_host_public, *server_host_private;
+	u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
+	u_char hash[SSH_DIGEST_MAX_LENGTH];
+	size_t sbloblen, slen;
+	size_t klen = 0, hashlen;
+	int kout, r;
 
 	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);
+	    kex->load_host_private_key == NULL) {
+		r = SSH_ERR_INVALID_ARGUMENT;
+		goto out;
+	}
+	if ((server_host_public = kex->load_host_public_key(kex->hostkey_type,
+	    ssh)) == NULL ||
+	    (server_host_private = kex->load_host_private_key(kex->hostkey_type,
+	    ssh)) == NULL) {
+		r = SSH_ERR_NO_HOSTKEY_LOADED;
+		goto out;
+	}
 
 	/* key, cert */
-	if ((dh_client_pub = BN_new()) == NULL)
-		fatal("dh_client_pub == NULL");
-	packet_get_bignum2(dh_client_pub);
-	packet_check_eom();
+	if ((dh_client_pub = BN_new()) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((r = sshpkt_get_bignum2(ssh, dh_client_pub)) != 0 ||
+	    (r = sshpkt_get_end(ssh)) != 0)
+		goto out;
 
 #ifdef DEBUG_KEXDH
 	fprintf(stderr, "dh_client_pub= ");
@@ -88,70 +121,89 @@ kexdh_server(Kex *kex)
 #endif
 
 #ifdef DEBUG_KEXDH
-	DHparams_print_fp(stderr, dh);
+	DHparams_print_fp(stderr, kex->dh);
 	fprintf(stderr, "pub= ");
-	BN_print_fp(stderr, dh->pub_key);
+	BN_print_fp(stderr, kex->dh->pub_key);
 	fprintf(stderr, "\n");
 #endif
-	if (!dh_pub_is_valid(dh, dh_client_pub))
-		packet_disconnect("bad client public DH value");
+	if (!dh_pub_is_valid(kex->dh, dh_client_pub)) {
+		sshpkt_disconnect(ssh, "bad client public DH value");
+		r = SSH_ERR_MESSAGE_INCOMPLETE;
+		goto out;
+	}
 
-	klen = DH_size(dh);
-	kbuf = xmalloc(klen);
-	if ((kout = DH_compute_key(kbuf, dh_client_pub, dh)) < 0)
-		fatal("DH_compute_key: failed");
+	klen = DH_size(kex->dh);
+	if ((kbuf = malloc(klen)) == NULL ||
+	    (shared_secret = BN_new()) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((kout = DH_compute_key(kbuf, dh_client_pub, kex->dh)) < 0 ||
+	    BN_bin2bn(kbuf, kout, shared_secret) == NULL) {
+		r = SSH_ERR_LIBCRYPTO_ERROR;
+		goto out;
+	}
 #ifdef DEBUG_KEXDH
 	dump_digest("shared secret", kbuf, kout);
 #endif
-	if ((shared_secret = BN_new()) == NULL)
-		fatal("kexdh_server: BN_new failed");
-	if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
-		fatal("kexdh_server: BN_bin2bn failed");
-	explicit_bzero(kbuf, klen);
-	free(kbuf);
-
-	key_to_blob(server_host_public, &server_host_key_blob, &sbloblen);
-
+	if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
+	    &sbloblen)) != 0)
+		goto out;
 	/* calc H */
-	kex_dh_hash(
+	hashlen = sizeof(hash);
+	if ((r = kex_dh_hash(
 	    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,
 	    dh_client_pub,
-	    dh->pub_key,
+	    kex->dh->pub_key,
 	    shared_secret,
-	    &hash, &hashlen
-	);
-	BN_clear_free(dh_client_pub);
+	    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);
+	if ((r = kex->sign(server_host_private, server_host_public,
+	    &signature, &slen, hash, hashlen, ssh->compat)) < 0)
+		goto out;
 
 	/* destroy_sensitive_data(); */
 
 	/* send server hostkey, DH pubkey 'f' and singed H */
-	packet_start(SSH2_MSG_KEXDH_REPLY);
-	packet_put_string(server_host_key_blob, sbloblen);
-	packet_put_bignum2(dh->pub_key);	/* f */
-	packet_put_string(signature, slen);
-	packet_send();
-
-	free(signature);
+	if ((r = sshpkt_start(ssh, SSH2_MSG_KEXDH_REPLY)) != 0 ||
+	    (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
+	    (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 ||	/* f */
+	    (r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0)
+		goto out;
+
+	if ((r = kex_derive_keys_bn(ssh, hash, hashlen, shared_secret)) == 0)
+		r = kex_send_newkeys(ssh);
+ out:
+	explicit_bzero(hash, sizeof(hash));
+	DH_free(kex->dh);
+	kex->dh = NULL;
+	if (dh_client_pub)
+		BN_clear_free(dh_client_pub);
+	if (kbuf) {
+		explicit_bzero(kbuf, klen);
+		free(kbuf);
+	}
+	if (shared_secret)
+		BN_clear_free(shared_secret);
 	free(server_host_key_blob);
-	/* have keys, free DH */
-	DH_free(dh);
-
-	kex_derive_keys_bn(kex, hash, hashlen, shared_secret);
-	BN_clear_free(shared_secret);
-	kex_finish(kex);
+	free(signature);
+	return r;
 }