1 files changed, 279 insertions, 0 deletions
diff --git a/crypto/openssh/kexgexc.c b/crypto/openssh/kexgexc.c
new file mode 100644
index 000000000000..e8e059a885aa
--- /dev/null
+++ b/crypto/openssh/kexgexc.c
@@ -0,0 +1,279 @@
+/* $OpenBSD: kexgexc.c,v 1.20 2015/01/26 06:10:03 djm Exp $ */
+/*
+ * Copyright (c) 2000 Niels Provos.  All rights reserved.
+ * Copyright (c) 2001 Markus Friedl.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "includes.h"
+
+#ifdef WITH_OPENSSL
+
+#include <sys/types.h>
+
+#include <openssl/dh.h>
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <signal.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 "compat.h"
+#include "dispatch.h"
+#include "ssherr.h"
+#include "sshbuf.h"
+
+static int input_kex_dh_gex_group(int, u_int32_t, void *);
+static int input_kex_dh_gex_reply(int, u_int32_t, void *);
+
+int
+kexgex_client(struct ssh *ssh)
+{
+	struct kex *kex = ssh->kex;
+	int r;
+	u_int nbits;
+
+	nbits = dh_estimate(kex->dh_need * 8);
+
+	kex->min = DH_GRP_MIN;
+	kex->max = DH_GRP_MAX;
+	kex->nbits = nbits;
+	if (ssh->compat & SSH_OLD_DHGEX) {
+		/* Old GEX request */
+		if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST_OLD))
+		    != 0 ||
+		    (r = sshpkt_put_u32(ssh, kex->nbits)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			goto out;
+		debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD(%u) sent", kex->nbits);
+	} else {
+		/* New GEX request */
+		if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_REQUEST)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, kex->min)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, kex->nbits)) != 0 ||
+		    (r = sshpkt_put_u32(ssh, kex->max)) != 0 ||
+		    (r = sshpkt_send(ssh)) != 0)
+			goto out;
+		debug("SSH2_MSG_KEX_DH_GEX_REQUEST(%u<%u<%u) sent",
+		    kex->min, kex->nbits, kex->max);
+	}
+#ifdef DEBUG_KEXDH
+	fprintf(stderr, "\nmin = %d, nbits = %d, max = %d\n",
+	    kex->min, kex->nbits, kex->max);
+#endif
+	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_GROUP,
+	    &input_kex_dh_gex_group);
+	r = 0;
+ out:
+	return r;
+}
+
+static int
+input_kex_dh_gex_group(int type, u_int32_t seq, void *ctxt)
+{
+	struct ssh *ssh = ctxt;
+	struct kex *kex = ssh->kex;
+	BIGNUM *p = NULL, *g = NULL;
+	int r, bits;
+
+	debug("got SSH2_MSG_KEX_DH_GEX_GROUP");
+
+	if ((p = BN_new()) == NULL ||
+	    (g = BN_new()) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	if ((r = sshpkt_get_bignum2(ssh, p)) != 0 ||
+	    (r = sshpkt_get_bignum2(ssh, g)) != 0 ||
+	    (r = sshpkt_get_end(ssh)) != 0)
+		goto out;
+	if ((bits = BN_num_bits(p)) < 0 ||
+	    (u_int)bits < kex->min || (u_int)bits > kex->max) {
+		r = SSH_ERR_DH_GEX_OUT_OF_RANGE;
+		goto out;
+	}
+	if ((kex->dh = dh_new_group(g, p)) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	p = g = NULL; /* belong to kex->dh now */
+
+	/* generate and send 'e', client DH public key */
+	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0 ||
+	    (r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_INIT)) != 0 ||
+	    (r = sshpkt_put_bignum2(ssh, kex->dh->pub_key)) != 0 ||
+	    (r = sshpkt_send(ssh)) != 0)
+		goto out;
+	debug("SSH2_MSG_KEX_DH_GEX_INIT sent");
+#ifdef DEBUG_KEXDH
+	DHparams_print_fp(stderr, kex->dh);
+	fprintf(stderr, "pub= ");
+	BN_print_fp(stderr, kex->dh->pub_key);
+	fprintf(stderr, "\n");
+#endif
+	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_GROUP, NULL);
+	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_REPLY, &input_kex_dh_gex_reply);
+	r = 0;
+out:
+	if (p)
+		BN_clear_free(p);
+	if (g)
+		BN_clear_free(g);
+	return r;
+}
+
+static int
+input_kex_dh_gex_reply(int type, u_int32_t seq, void *ctxt)
+{
+	struct ssh *ssh = ctxt;
+	struct kex *kex = ssh->kex;
+	BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
+	struct sshkey *server_host_key = NULL;
+	u_char *kbuf = NULL, *signature = NULL, *server_host_key_blob = NULL;
+	u_char hash[SSH_DIGEST_MAX_LENGTH];
+	size_t klen = 0, slen, sbloblen, hashlen;
+	int kout, r;
+
+	debug("got SSH2_MSG_KEX_DH_GEX_REPLY");
+	if (kex->verify_host_key == NULL) {
+		r = SSH_ERR_INVALID_ARGUMENT;
+		goto out;
+	}
+	/* key, cert */
+	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 (server_host_key->type != kex->hostkey_type ||
+	    (kex->hostkey_type == KEY_ECDSA &&
+	    server_host_key->ecdsa_nid != kex->hostkey_nid)) {
+		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;
+	}
+	/* DH parameter f, server public DH key */
+	if ((dh_server_pub = BN_new()) == NULL) {
+		r = SSH_ERR_ALLOC_FAIL;
+		goto out;
+	}
+	/* signed H */
+	if ((r = sshpkt_get_bignum2(ssh, dh_server_pub)) != 0 ||
+	    (r = sshpkt_get_string(ssh, &signature, &slen)) != 0 ||
+	    (r = sshpkt_get_end(ssh)) != 0)
+		goto out;
+#ifdef DEBUG_KEXDH
+	fprintf(stderr, "dh_server_pub= ");
+	BN_print_fp(stderr, dh_server_pub);
+	fprintf(stderr, "\n");
+	debug("bits %d", BN_num_bits(dh_server_pub));
+#endif
+	if (!dh_pub_is_valid(kex->dh, dh_server_pub)) {
+		sshpkt_disconnect(ssh, "bad server public DH value");
+		r = SSH_ERR_MESSAGE_INCOMPLETE;
+		goto out;
+	}
+
+	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_server_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 (ssh->compat & SSH_OLD_DHGEX)
+		kex->min = kex->max = -1;
+
+	/* calc and verify H */
+	hashlen = sizeof(hash);
+	if ((r = kexgex_hash(
+	    kex->hash_alg,
+	    kex->client_version_string,
+	    kex->server_version_string,
+	    sshbuf_ptr(kex->my), sshbuf_len(kex->my),
+	    sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
+	    server_host_key_blob, sbloblen,
+	    kex->min, kex->nbits, kex->max,
+	    kex->dh->p, kex->dh->g,
+	    kex->dh->pub_key,
+	    dh_server_pub,
+	    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 = 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);
+	}
+
+	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_server_pub)
+		BN_clear_free(dh_server_pub);
+	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 /* WITH_OPENSSL */