1 files changed, 182 insertions, 117 deletions

diff --git a/crypto/openssh/kexgexc.c b/crypto/openssh/kexgexc.c
index 355b7ba..71ff133 100644
--- a/crypto/openssh/kexgexc.c
+++ b/crypto/openssh/kexgexc.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kexgexc.c,v 1.17 2014/02/02 03:44:31 djm Exp $ */
+/* $OpenBSD: kexgexc.c,v 1.22 2015/05/26 23:23:40 dtucker Exp $ */
 /*
  * Copyright (c) 2000 Niels Provos.  All rights reserved.
  * Copyright (c) 2001 Markus Friedl.  All rights reserved.
@@ -26,6 +26,9 @@
 
 #include "includes.h"
 
+#ifdef WITH_OPENSSL
+
+#include <sys/param.h>
 #include <sys/types.h>
 
 #include <openssl/dh.h>
@@ -35,173 +38,235 @@
 #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 "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 *);
 
-void
-kexgex_client(Kex *kex)
+int
+kexgex_client(struct ssh *ssh)
 {
-	BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
-	BIGNUM *p = NULL, *g = NULL;
-	Key *server_host_key;
-	u_char *kbuf, *hash, *signature = NULL, *server_host_key_blob = NULL;
-	u_int klen, slen, sbloblen, hashlen;
-	int kout;
-	int min, max, nbits;
-	DH *dh;
+	struct kex *kex = ssh->kex;
+	int r;
+	u_int nbits;
 
 	nbits = dh_estimate(kex->dh_need * 8);
 
-	if (datafellows & SSH_OLD_DHGEX) {
-		/* Old GEX request */
-		packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
-		packet_put_int(nbits);
-		min = DH_GRP_MIN;
-		max = DH_GRP_MAX;
-
-		debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD(%u) sent", nbits);
-	} else {
-		/* New GEX request */
-		min = DH_GRP_MIN;
-		max = DH_GRP_MAX;
-		packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
-		packet_put_int(min);
-		packet_put_int(nbits);
-		packet_put_int(max);
-
-		debug("SSH2_MSG_KEX_DH_GEX_REQUEST(%u<%u<%u) sent",
-		    min, nbits, max);
-	}
+	kex->min = DH_GRP_MIN;
+	kex->max = DH_GRP_MAX;
+	kex->nbits = nbits;
+	if (datafellows & SSH_BUG_DHGEX_LARGE)
+		kex->nbits = MIN(kex->nbits, 4096);
+	/* 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",
-	    min, nbits, max);
+	    kex->min, kex->nbits, kex->max);
 #endif
-	packet_send();
-
-	debug("expecting SSH2_MSG_KEX_DH_GEX_GROUP");
-	packet_read_expect(SSH2_MSG_KEX_DH_GEX_GROUP);
+	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_GROUP,
+	    &input_kex_dh_gex_group);
+	r = 0;
+ out:
+	return r;
+}
 
-	if ((p = BN_new()) == NULL)
-		fatal("BN_new");
-	packet_get_bignum2(p);
-	if ((g = BN_new()) == NULL)
-		fatal("BN_new");
-	packet_get_bignum2(g);
-	packet_check_eom();
+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;
 
-	if (BN_num_bits(p) < min || BN_num_bits(p) > max)
-		fatal("DH_GEX group out of range: %d !< %d !< %d",
-		    min, BN_num_bits(p), max);
+	debug("got SSH2_MSG_KEX_DH_GEX_GROUP");
 
-	dh = dh_new_group(g, p);
-	dh_gen_key(dh, kex->we_need * 8);
+	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, 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
+	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;
+}
 
-	debug("SSH2_MSG_KEX_DH_GEX_INIT sent");
-	/* generate and send 'e', client DH public key */
-	packet_start(SSH2_MSG_KEX_DH_GEX_INIT);
-	packet_put_bignum2(dh->pub_key);
-	packet_send();
-
-	debug("expecting SSH2_MSG_KEX_DH_GEX_REPLY");
-	packet_read_expect(SSH2_MSG_KEX_DH_GEX_REPLY);
+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 */
-	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 (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)
-		fatal("dh_server_pub == NULL");
-	packet_get_bignum2(dh_server_pub);
-
+	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;
+	}
 
-	/* signed H */
-	signature = packet_get_string(&slen);
-	packet_check_eom();
-
-	if (!dh_pub_is_valid(dh, dh_server_pub))
-		packet_disconnect("bad server public DH value");
-
-	klen = DH_size(dh);
-	kbuf = xmalloc(klen);
-	if ((kout = DH_compute_key(kbuf, dh_server_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_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 ((shared_secret = BN_new()) == NULL)
-		fatal("kexgex_client: BN_new failed");
-	if (BN_bin2bn(kbuf, kout, shared_secret) == NULL)
-		fatal("kexgex_client: BN_bin2bn failed");
-	explicit_bzero(kbuf, klen);
-	free(kbuf);
-
-	if (datafellows & SSH_OLD_DHGEX)
-		min = max = -1;
+	if (ssh->compat & SSH_OLD_DHGEX)
+		kex->min = kex->max = -1;
 
 	/* calc and verify H */
-	kexgex_hash(
+	hashlen = sizeof(hash);
+	if ((r = kexgex_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,
-	    min, nbits, max,
-	    dh->p, dh->g,
-	    dh->pub_key,
+	    kex->min, kex->nbits, kex->max,
+	    kex->dh->p, kex->dh->g,
+	    kex->dh->pub_key,
 	    dh_server_pub,
 	    shared_secret,
-	    &hash, &hashlen
-	);
-
-	/* have keys, free DH */
-	DH_free(dh);
-	free(server_host_key_blob);
-	BN_clear_free(dh_server_pub);
+	    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));
+	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 */