示例#1
0
static int
input_gssapi_exchange_complete(int type, u_int32_t plen, struct ssh *ssh)
{
	Authctxt *authctxt = ssh->authctxt;
	int r, authenticated;
	const char *displayname;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	/*
	 * We don't need to check the status, because we're only enabled in
	 * the dispatcher once the exchange is complete
	 */

	if ((r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	authenticated = PRIVSEP(ssh_gssapi_userok(authctxt->user));

	if ((!use_privsep || mm_is_monitor()) &&
	    (displayname = ssh_gssapi_displayname()) != NULL)
		auth2_record_info(authctxt, "%s", displayname);

	authctxt->postponed = 0;
	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);
	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_MIC, NULL);
	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
	userauth_finish(ssh, authenticated, "gssapi-with-mic", NULL);
	return 0;
}
示例#2
0
static Channel *
server_request_direct_tcpip(struct ssh *ssh)
{
	Channel *c = NULL;
	char *target, *originator;
	u_int target_port, originator_port;
	int r;

	if ((r = sshpkt_get_cstring(ssh, &target, NULL)) != 0 ||
	    (r = sshpkt_get_u32(ssh, &target_port)) != 0 ||
	    (r = sshpkt_get_cstring(ssh, &originator, NULL)) != 0 ||
	    (r = sshpkt_get_u32(ssh, &originator_port)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	debug("server_request_direct_tcpip: originator %s port %d, target %s "
	    "port %d", originator, originator_port, target, target_port);

	/* XXX fine grained permissions */
	if ((options.allow_tcp_forwarding & FORWARD_LOCAL) != 0 &&
	    !no_port_forwarding_flag) {
		c = channel_connect_to_port(ssh, target, target_port,
		    "direct-tcpip", "direct-tcpip");
	} else {
		logit("refused local port forward: "
		    "originator %s port %d, target %s port %d",
		    originator, originator_port, target, target_port);
	}

	free(originator);
	free(target);

	return c;
}
示例#3
0
static Channel *
server_request_session(struct ssh *ssh)
{
	Channel *c;
	int r;

	debug("input_session_request");
	if ((r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	if (no_more_sessions) {
		ssh_packet_disconnect(ssh,
		    "Possible attack: attempt to open a session "
		    "after additional sessions disabled");
	}

	/*
	 * A server session has no fd to read or write until a
	 * CHANNEL_REQUEST for a shell is made, so we set the type to
	 * SSH_CHANNEL_LARVAL.  Additionally, a callback for handling all
	 * CHANNEL_REQUEST messages is registered.
	 */
	c = channel_new(ssh, "session", SSH_CHANNEL_LARVAL,
	    -1, -1, -1, /*window size*/0, CHAN_SES_PACKET_DEFAULT,
	    0, "server-session", 1);
	if (session_open(ssh, c->self) != 1) {
		debug("session open failed, free channel %d", c->self);
		channel_free(c);
		return NULL;
	}
	channel_register_cleanup(c->self, session_close_by_channel, 0);
	return c;
}
示例#4
0
static int
userauth_none(struct ssh *ssh)
{
    int r;

    none_enabled = 0;
    if ((r = sshpkt_get_end(ssh)) != 0)
        fatal("%s: %s", __func__, ssh_err(r));
    if (options.permit_empty_passwd && options.password_authentication)
        return (PRIVSEP(auth_password(ssh->authctxt, "")));
    return (0);
}
示例#5
0
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;
}
示例#6
0
static int
input_kex_dh_gex_request(int type, u_int32_t seq, void *ctxt)
{
	struct ssh *ssh = ctxt;
	struct kex *kex = ssh->kex;
	int r;
	u_int min = 0, max = 0, nbits = 0;

	debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
	if ((r = sshpkt_get_u32(ssh, &min)) != 0 ||
	    (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
	    (r = sshpkt_get_u32(ssh, &max)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		goto out;
	kex->nbits = nbits;
	kex->min = min;
	kex->max = max;
	min = MAX(DH_GRP_MIN, min);
	max = MIN(DH_GRP_MAX, max);
	nbits = MAX(DH_GRP_MIN, nbits);
	nbits = MIN(DH_GRP_MAX, nbits);

	if (kex->max < kex->min || kex->nbits < kex->min ||
	    kex->max < kex->nbits) {
		r = SSH_ERR_DH_GEX_OUT_OF_RANGE;
		goto out;
	}

	/* Contact privileged parent */
	kex->dh = PRIVSEP(choose_dh(min, nbits, max));
	if (kex->dh == NULL) {
		sshpkt_disconnect(ssh, "no matching DH grp found");
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	debug("SSH2_MSG_KEX_DH_GEX_GROUP sent");
	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_GROUP)) != 0 ||
	    (r = sshpkt_put_bignum2(ssh, kex->dh->p)) != 0 ||
	    (r = sshpkt_put_bignum2(ssh, kex->dh->g)) != 0 ||
	    (r = sshpkt_send(ssh)) != 0)
		goto out;

	/* Compute our exchange value in parallel with the client */
	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
		goto out;

	debug("expecting SSH2_MSG_KEX_DH_GEX_INIT");
	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_INIT, &input_kex_dh_gex_init);
	r = 0;
 out:
	return r;
}
示例#7
0
/* ARGSUSED */
int
kex_input_kexinit(int type, u_int32_t seq, void *ctxt)
{
	struct ssh *ssh = ctxt;
	struct kex *kex = ssh->kex;
	const u_char *ptr;
	u_int i;
	size_t dlen;
	int r;

	debug("SSH2_MSG_KEXINIT received");
	if (kex == NULL)
		return SSH_ERR_INVALID_ARGUMENT;

	ssh_dispatch_set(ssh, SSH2_MSG_KEXINIT, NULL);
	ptr = sshpkt_ptr(ssh, &dlen);
	if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
		return r;

	/* discard packet */
	for (i = 0; i < KEX_COOKIE_LEN; i++)
		if ((r = sshpkt_get_u8(ssh, NULL)) != 0)
			return r;
	for (i = 0; i < PROPOSAL_MAX; i++)
		if ((r = sshpkt_get_string(ssh, NULL, NULL)) != 0)
			return r;
	/*
	 * XXX RFC4253 sec 7: "each side MAY guess" - currently no supported
	 * KEX method has the server move first, but a server might be using
	 * a custom method or one that we otherwise don't support. We should
	 * be prepared to remember first_kex_follows here so we can eat a
	 * packet later.
	 * XXX2 - RFC4253 is kind of ambiguous on what first_kex_follows means
	 * for cases where the server *doesn't* go first. I guess we should
	 * ignore it when it is set for these cases, which is what we do now.
	 */
	if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||	/* first_kex_follows */
	    (r = sshpkt_get_u32(ssh, NULL)) != 0 ||	/* reserved */
	    (r = sshpkt_get_end(ssh)) != 0)
			return r;

	if (!(kex->flags & KEX_INIT_SENT))
		if ((r = kex_send_kexinit(ssh)) != 0)
			return r;
	if ((r = kex_choose_conf(ssh)) != 0)
		return r;

	if (kex->kex_type < KEX_MAX && kex->kex[kex->kex_type] != NULL)
		return (kex->kex[kex->kex_type])(ssh);

	return SSH_ERR_INTERNAL_ERROR;
}
示例#8
0
static int
server_input_eof(int type, u_int32_t seq, struct ssh *ssh)
{
	int r;

	/*
	 * Eof from the client.  The stdin descriptor to the
	 * program will be closed when all buffered data has
	 * drained.
	 */
	debug("EOF received for stdin.");
	r = sshpkt_get_end(ssh);
	stdin_eof = 1;
	return r;
}
示例#9
0
static int
server_input_window_size(int type, u_int32_t seq, struct ssh *ssh)
{
	u_int row, col, xpixel, ypixel;
	int r;

	if ((r = sshpkt_get_u32(ssh, &row)) != 0 ||
	    (r = sshpkt_get_u32(ssh, &col)) != 0 ||
	    (r = sshpkt_get_u32(ssh, &xpixel)) != 0 ||
	    (r = sshpkt_get_u32(ssh, &ypixel)) != 0 ||
	    (r = sshpkt_get_end(ssh)))
		return r;

	debug("Window change received.");
	if (fdin != -1)
		pty_change_window_size(fdin, row, col, xpixel, ypixel);
	return 0;
}
示例#10
0
文件: kex.c 项目: djmdjm/libopenssh
static int
kex_input_newkeys(int type, u_int32_t seq, struct ssh *ssh)
{
	struct kex *kex = ssh->kex;
	int r;

	debug("SSH2_MSG_NEWKEYS received");
	ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_protocol_error);
	if ((r = sshpkt_get_end(ssh)) != 0)
		return r;
	kex->done = 1;
	sshbuf_reset(kex->peer);
	/* sshbuf_reset(kex->my); */
	kex->flags &= ~KEX_INIT_SENT;
	free(kex->name);
	kex->name = NULL;
	return 0;
}
示例#11
0
/*
 * Attempt J-PAKE authentication.
 */
static int
userauth_jpake(struct ssh *ssh)
{
	Authctxt *authctxt = ssh->authctxt;
	int r, authenticated = 0;

	if ((r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	debug("[email protected] requested");

	if (authctxt->user != NULL) {
		if (authctxt->jpake_ctx == NULL)
			authctxt->jpake_ctx = jpake_new();
		if (options.zero_knowledge_password_authentication)
			authenticated = auth2_jpake_start(ssh);
	}

	return authenticated;
}
示例#12
0
文件: kex.c 项目: johnjohnsp1/ncrack
static int
kex_input_newkeys(ncrack_ssh_state *nstate)
{
	//struct ssh *ssh = ctxt;
	struct kex *kex = nstate->kex;
	int r;

	debug("SSH2_MSG_NEWKEYS received");
	//ssh_dispatch_set(ssh, SSH2_MSG_NEWKEYS, &kex_protocol_error);
	if ((r = sshpkt_get_end(nstate)) != 0)
		return r;
	kex->done = 1;
	sshbuf_reset(kex->peer);
	/* sshbuf_reset(kex->my); */
	kex->flags &= ~KEX_INIT_SENT;
	free(kex->name);
	kex->name = NULL;

	return 0;
}
示例#13
0
文件: kex.c 项目: mpitzl/libopenssh
/* ARGSUSED */
int
kex_input_kexinit(int type, u_int32_t seq, struct ssh *ssh)
{
	Kex *kex = ssh->kex;
	u_char *ptr;
	u_int i;
	size_t dlen;
	int r;

	debug("SSH2_MSG_KEXINIT received");
	if (kex == NULL)
		return SSH_ERR_INVALID_ARGUMENT;

	ptr = sshpkt_ptr(ssh, &dlen);
	if ((r = sshbuf_put(kex->peer, ptr, dlen)) != 0)
		return r;

	/* discard packet */
	for (i = 0; i < KEX_COOKIE_LEN; i++)
		if ((r = sshpkt_get_u8(ssh, NULL)) != 0)
			return r;
	for (i = 0; i < PROPOSAL_MAX; i++)
		if ((r = sshpkt_get_string(ssh, NULL, NULL)) != 0)
			return r;
	if ((r = sshpkt_get_u8(ssh, NULL)) != 0 ||
	    (r = sshpkt_get_u32(ssh, NULL)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
			return r;

	if (!(kex->flags & KEX_INIT_SENT))
		if ((r = kex_send_kexinit(ssh)) != 0)
			return r;
	if ((r = kex_choose_conf(ssh)) != 0)
		return r;

	if (kex->kex_type >= 0 && kex->kex_type < KEX_MAX &&
	    kex->kex[kex->kex_type] != NULL)
		return (kex->kex[kex->kex_type])(ssh);

	return SSH_ERR_INTERNAL_ERROR;
}
示例#14
0
static int
server_input_channel_req(int type, u_int32_t seq, struct ssh *ssh)
{
	Channel *c;
	int r, success = 0;
	u_int id;
	u_char reply;
	char *rtype = NULL;

	if ((r = sshpkt_get_u32(ssh, &id)) != 0 ||
	    (r = sshpkt_get_cstring(ssh, &rtype, NULL)) != 0 ||
	    (r = sshpkt_get_u8(ssh, &reply)) != 0)
		goto out;

	debug("server_input_channel_req: channel %u request %s reply %d",
	    id, rtype, reply);

	if ((c = channel_lookup(id)) == NULL)
		ssh_packet_disconnect(ssh, "server_input_channel_req: "
		    "unknown channel %u", id);
	if (!strcmp(rtype, "*****@*****.**")) {
		if ((r = sshpkt_get_end(ssh)) != 0)
			goto out;
		chan_rcvd_eow(c);
	} else if ((c->type == SSH_CHANNEL_LARVAL ||
	    c->type == SSH_CHANNEL_OPEN) && strcmp(c->ctype, "session") == 0)
		success = session_input_channel_req(c, rtype);
	if (reply && !(c->flags & CHAN_CLOSE_SENT)) {
		if ((r = sshpkt_start(ssh, success ? SSH2_MSG_CHANNEL_SUCCESS :
		    SSH2_MSG_CHANNEL_FAILURE)) != 0 ||
		    (r = sshpkt_put_u32(ssh, c->remote_id)) != 0 ||
		    (r = sshpkt_send(ssh)) != 0)
			goto out;
	}
	r = 0;
 out:
	if (rtype)
		free(rtype);
	return r;
}
示例#15
0
文件: auth2.c 项目: djmdjm/libopenssh
/*ARGSUSED*/
static int
input_service_request(int type, u_int32_t seq, struct ssh *ssh)
{
    struct authctxt *authctxt = ssh->authctxt;
    char *service = NULL;
    int r, acceptit = 0;

    if ((r = sshpkt_get_cstring(ssh, &service, NULL)) != 0 ||
            (r = sshpkt_get_end(ssh)) != 0)
        goto out;

    if (authctxt == NULL)
        fatal("input_service_request: no authctxt");

    if (strcmp(service, "ssh-userauth") == 0) {
        if (!authctxt->success) {
            acceptit = 1;
            /* now we can handle user-auth requests */
            ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST,
                             &input_userauth_request);
        }
    }
    /* XXX all other service requests are denied */

    if (acceptit) {
        if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_ACCEPT)) != 0 ||
                (r = sshpkt_put_cstring(ssh, service)) != 0 ||
                (r = sshpkt_send(ssh)) != 0)
            goto out;
        ssh_packet_write_wait(ssh);
    } else {
        debug("bad service request %s", service);
        ssh_packet_disconnect(ssh, "bad service request %s", service);
    }
    r = 0;
out:
    free(service);
    return r;
}
示例#16
0
static int
userauth_passwd(struct ssh *ssh)
{
	char *password;
	int authenticated = 0, r;
	u_char change;
	size_t len;

	if ((r = sshpkt_get_u8(ssh, &change)) != 0 ||
	    (r = sshpkt_get_cstring(ssh, &password, &len)) != 0 ||
	    (change && (r = sshpkt_get_cstring(ssh, NULL, NULL)) != 0) ||
	    (r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	if (change)
		logit("password change not supported");
	else if (PRIVSEP(auth_password(ssh, password)) == 1)
		authenticated = 1;
	explicit_bzero(password, len);
	free(password);
	return authenticated;
}
示例#17
0
int
kex_input_ext_info(int type, u_int32_t seq, void *ctxt)
{
	struct ssh *ssh = ctxt;
	struct kex *kex = ssh->kex;
	u_int32_t i, ninfo;
	char *name, *val, *found;
	int r;

	debug("SSH2_MSG_EXT_INFO received");
	ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &kex_protocol_error);
	if ((r = sshpkt_get_u32(ssh, &ninfo)) != 0)
		return r;
	for (i = 0; i < ninfo; i++) {
		if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0)
			return r;
		if ((r = sshpkt_get_cstring(ssh, &val, NULL)) != 0) {
			free(name);
			return r;
		}
		debug("%s: %s=<%s>", __func__, name, val);
		if (strcmp(name, "server-sig-algs") == 0) {
			found = match_list("rsa-sha2-256", val, NULL);
			if (found) {
				kex->rsa_sha2 = 256;
				free(found);
			}
			found = match_list("rsa-sha2-512", val, NULL);
			if (found) {
				kex->rsa_sha2 = 512;
				free(found);
			}
		}
		free(name);
		free(val);
	}
	return sshpkt_get_end(ssh);
}
示例#18
0
static int
server_input_stdin_data(int type, u_int32_t seq, struct ssh *ssh)
{
	u_char *data = NULL;
	size_t data_len;
	int r;

	/* Stdin data from the client.  Append it to the buffer. */
	/* Ignore any data if the client has closed stdin. */
	if (fdin == -1)
		return 0;
	if ((r = sshpkt_get_string(ssh, &data, &data_len)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0 ||
	    (r = sshbuf_put(stdin_buffer, data, data_len)) != 0)
		goto out;
	r = 0;
 out:
	if (data) {
		explicit_bzero(data, data_len);
		free(data);
	}
	return r;
}
示例#19
0
static int
input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh)
{
	Authctxt *authctxt = ssh->authctxt;
	Gssctxt *gssctxt;
	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	gss_buffer_desc recv_tok;
	OM_uint32 maj_status;
	int r;
	u_char *p;
	size_t len;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	gssctxt = authctxt->methoddata;
	if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));
	recv_tok.value = p;
	recv_tok.length = len;

	/* Push the error token into GSSAPI to see what it says */
	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	    &send_tok, NULL));

	free(recv_tok.value);

	/* We can't return anything to the client, even if we wanted to */
	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
	ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, NULL);

	/* The client will have already moved on to the next auth */

	gss_release_buffer(&maj_status, &send_tok);
	return 0;
}
示例#20
0
int
auth_rsa_challenge_dialog(struct sshkey *key)
{
	struct ssh *ssh = active_state;
	BIGNUM *challenge, *encrypted_challenge;
	u_char response[16];
	int r, success;

	if ((encrypted_challenge = BN_new()) == NULL)
		fatal("auth_rsa_challenge_dialog: BN_new() failed");

	challenge = PRIVSEP(auth_rsa_generate_challenge(key));

	/* Encrypt the challenge with the public key. */
	if ((r = rsa_public_encrypt(encrypted_challenge, challenge,
	    key->rsa)) != 0)
		fatal("%s: rsa_public_encrypt: %s", __func__, ssh_err(r));

	/* Send the encrypted challenge to the client. */
	if ((r = sshpkt_start(ssh, SSH_SMSG_AUTH_RSA_CHALLENGE)) != 0 ||
	    (r = sshpkt_put_bignum1(ssh, encrypted_challenge)) != 0 ||
	    (r = sshpkt_send(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));
	BN_clear_free(encrypted_challenge);
	ssh_packet_write_wait(ssh);

	/* Wait for a response. */
	ssh_packet_read_expect(ssh, SSH_CMSG_AUTH_RSA_RESPONSE);
	if ((r = sshpkt_get(ssh, &response, sizeof(response))) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	success = PRIVSEP(auth_rsa_verify_response(key, challenge, response));
	BN_clear_free(challenge);
	return (success);
}
示例#21
0
static int
input_kex_c25519_init(int type, u_int32_t seq, struct ssh *ssh)
{
	struct kex *kex = ssh->kex;
	struct sshkey *server_host_private, *server_host_public;
	struct sshbuf *shared_secret = NULL;
	u_char *server_host_key_blob = NULL, *signature = NULL;
	u_char server_key[CURVE25519_SIZE];
	u_char *client_pubkey = NULL;
	u_char server_pubkey[CURVE25519_SIZE];
	u_char hash[SSH_DIGEST_MAX_LENGTH];
	size_t slen, pklen, sbloblen, hashlen;
	int r;

	/* generate private key */
	kexc25519_keygen(server_key, server_pubkey);
#ifdef DEBUG_KEXECDH
	dump_digest("server private key:", server_key, sizeof(server_key));
#endif
	if (kex->load_host_public_key == NULL ||
	    kex->load_host_private_key == NULL) {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	server_host_public = kex->load_host_public_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	server_host_private = kex->load_host_private_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	if (server_host_public == NULL) {
		r = SSH_ERR_NO_HOSTKEY_LOADED;
		goto out;
	}

	if ((r = sshpkt_get_string(ssh, &client_pubkey, &pklen)) != 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("client public key:", client_pubkey, CURVE25519_SIZE);
#endif

	if ((shared_secret = sshbuf_new()) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = kexc25519_shared_key(server_key, client_pubkey,
	    shared_secret)) < 0)
		goto out;

	/* calc H */
	if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
	    &sbloblen)) != 0)
		goto out;
	hashlen = sizeof(hash);
	if ((r = kex_c25519_hash(
	    kex->hash_alg,
	    kex->client_version_string,
	    kex->server_version_string,
	    sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
	    sshbuf_ptr(kex->my), sshbuf_len(kex->my),
	    server_host_key_blob, sbloblen,
	    client_pubkey,
	    server_pubkey,
	    sshbuf_ptr(shared_secret), sshbuf_len(shared_secret),
	    hash, &hashlen)) < 0)
		goto out;

	/* save session id := H */
	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);
	}

	/* sign H */
	if ((r = kex->sign(server_host_private, server_host_public, &signature,
	     &slen, hash, hashlen, kex->hostkey_alg, ssh->compat)) < 0)
		goto out;

	/* send server hostkey, ECDH pubkey 'Q_S' and signed H */
	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_REPLY)) != 0 ||
	    (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
	    (r = sshpkt_put_string(ssh, server_pubkey, sizeof(server_pubkey))) != 0 ||
	    (r = sshpkt_put_string(ssh, signature, slen)) != 0 ||
	    (r = sshpkt_send(ssh)) != 0)
		goto out;

	if ((r = kex_derive_keys(ssh, hash, hashlen, shared_secret)) == 0)
		r = kex_send_newkeys(ssh);
out:
	explicit_bzero(hash, sizeof(hash));
	explicit_bzero(server_key, sizeof(server_key));
	free(server_host_key_blob);
	free(signature);
	free(client_pubkey);
	sshbuf_free(shared_secret);
	return r;
}
示例#22
0
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 */
	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 ||
	    (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;
	}

	/* Q_S, server public key */
	/* 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);
	sshkey_dump_ec_point(group, server_public);
#endif
	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;
	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 ||
	    BN_bin2bn(kbuf, klen, shared_secret) == NULL) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}

#ifdef DEBUG_KEXECDH
	dump_digest("shared secret", kbuf, klen);
#endif
	/* calc and verify H */
	hashlen = sizeof(hash);
	if ((r = kex_ecdh_hash(
	    kex->hash_alg,
	    group,
	    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,
	    EC_KEY_get0_public_key(client_key),
	    server_public,
	    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));
	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;
}
示例#23
0
文件: kexdhs.c 项目: 2asoft/freebsd
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) {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	server_host_public = kex->load_host_public_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	server_host_private = kex->load_host_private_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	if (server_host_public == NULL) {
		r = SSH_ERR_NO_HOSTKEY_LOADED;
		goto out;
	}

	/* key, cert */
	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= ");
	BN_print_fp(stderr, dh_client_pub);
	fprintf(stderr, "\n");
	debug("bits %d", BN_num_bits(dh_client_pub));
#endif

#ifdef DEBUG_KEXDH
	DHparams_print_fp(stderr, kex->dh);
	fprintf(stderr, "pub= ");
	BN_print_fp(stderr, kex->dh->pub_key);
	fprintf(stderr, "\n");
#endif
	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(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 ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
	    &sbloblen)) != 0)
		goto out;
	/* calc H */
	hashlen = sizeof(hash);
	if ((r = kex_dh_hash(
	    kex->client_version_string,
	    kex->server_version_string,
	    sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
	    sshbuf_ptr(kex->my), sshbuf_len(kex->my),
	    server_host_key_blob, sbloblen,
	    dh_client_pub,
	    kex->dh->pub_key,
	    shared_secret,
	    hash, &hashlen)) != 0)
		goto out;

	/* save session id := H */
	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);
	}

	/* sign H */
	if ((r = kex->sign(server_host_private, server_host_public, &signature,
	     &slen, hash, hashlen, kex->hostkey_alg, ssh->compat)) < 0)
		goto out;

	/* destroy_sensitive_data(); */

	/* send server hostkey, DH pubkey 'f' and singed H */
	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);
	free(signature);
	return r;
}
示例#24
0
static int
input_userauth_info_response(int type, u_int32_t seq, struct ssh *ssh)
{
	struct authctxt *authctxt = ssh->authctxt;
	struct kbdintctxt *kbdintctxt;
	int authenticated = 0, res;
	int r;
	u_int i, nresp;
	const char *devicename = NULL;
	char **response = NULL;

	if (authctxt == NULL)
		fatal("input_userauth_info_response: no authctxt");
	kbdintctxt = authctxt->kbdintctxt;
	if (kbdintctxt == NULL || kbdintctxt->ctxt == NULL)
		fatal("input_userauth_info_response: no kbdintctxt");
	if (kbdintctxt->device == NULL)
		fatal("input_userauth_info_response: no device");

	authctxt->postponed = 0;	/* reset */
	if ((r = sshpkt_get_u32(ssh, &nresp)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));
	if (nresp != kbdintctxt->nreq)
		fatal("input_userauth_info_response: wrong number of replies");
	if (nresp > 100)
		fatal("input_userauth_info_response: too many replies");
	if (nresp > 0) {
		response = xcalloc(nresp, sizeof(char *));
		for (i = 0; i < nresp; i++)
			if ((r = sshpkt_get_cstring(ssh, &response[i],
			    NULL)) != 0)
				fatal("%s: %s", __func__, ssh_err(r));
	}
	if ((r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	res = kbdintctxt->device->respond(kbdintctxt->ctxt, nresp, response);

	for (i = 0; i < nresp; i++) {
		explicit_bzero(response[i], strlen(response[i]));
		free(response[i]);
	}
	free(response);

	switch (res) {
	case 0:
		/* Success! */
		authenticated = authctxt->valid ? 1 : 0;
		break;
	case 1:
		/* Authentication needs further interaction */
		if (send_userauth_info_request(ssh) == 1)
			authctxt->postponed = 1;
		break;
	default:
		/* Failure! */
		break;
	}
	devicename = kbdintctxt->device->name;
	if (!authctxt->postponed) {
		if (authenticated) {
			auth2_challenge_stop(ssh);
		} else {
			/* start next device */
			/* may set authctxt->postponed */
			auth2_challenge_start(ssh);
		}
	}
	userauth_finish(ssh, authenticated, "keyboard-interactive",
	    devicename);
	return 0;
}
示例#25
0
static int
input_kex_c25519_reply(int type, u_int32_t seq, struct ssh *ssh)
{
	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;
	size_t slen, pklen, sbloblen, hashlen;
	int r;

	if (kex->verify_host_key == NULL) {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}

	/* hostkey */
	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 */
	/* 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

	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 */
	if ((r = kex_c25519_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->c25519_client_pubkey,
	    server_pubkey,
	    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 = 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(ssh, hash, hashlen, sshbuf_ptr(shared_secret),
	    sshbuf_len(shared_secret))) == 0)
		r = kex_send_newkeys(ssh);

	r = 0;
out:
	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;
}
示例#26
0
static int
input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh)
{
	Authctxt *authctxt = ssh->authctxt;
	Gssctxt *gssctxt;
	gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
	gss_buffer_desc recv_tok;
	OM_uint32 maj_status, min_status, flags;
	u_char *p;
	size_t len;
	int r;

	if (authctxt == NULL || (authctxt->methoddata == NULL && !use_privsep))
		fatal("No authentication or GSSAPI context");

	gssctxt = authctxt->methoddata;
	if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		fatal("%s: %s", __func__, ssh_err(r));

	recv_tok.value = p;
	recv_tok.length = len;
	maj_status = PRIVSEP(ssh_gssapi_accept_ctx(gssctxt, &recv_tok,
	    &send_tok, &flags));

	free(p);

	if (GSS_ERROR(maj_status)) {
		if (send_tok.length != 0) {
			if ((r = sshpkt_start(ssh,
			    SSH2_MSG_USERAUTH_GSSAPI_ERRTOK)) != 0 ||
			    (r = sshpkt_put_string(ssh, send_tok.value,
			    send_tok.length)) != 0 ||
			    (r = sshpkt_send(ssh)) != 0)
				fatal("%s: %s", __func__, ssh_err(r));
		}
		authctxt->postponed = 0;
		ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
		userauth_finish(ssh, 0, "gssapi-with-mic", NULL);
	} else {
		if (send_tok.length != 0) {
			if ((r = sshpkt_start(ssh,
			    SSH2_MSG_USERAUTH_GSSAPI_TOKEN)) != 0 ||
			    (r = sshpkt_put_string(ssh, send_tok.value,
			    send_tok.length)) != 0 ||
			    (r = sshpkt_send(ssh)) != 0)
				fatal("%s: %s", __func__, ssh_err(r));
		}
		if (maj_status == GSS_S_COMPLETE) {
			ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
			if (flags & GSS_C_INTEG_FLAG)
				ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_MIC,
				    &input_gssapi_mic);
			else
				ssh_dispatch_set(ssh,
				    SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE,
				    &input_gssapi_exchange_complete);
		}
	}

	gss_release_buffer(&min_status, &send_tok);
	return 0;
}
示例#27
0
/*
 * Checks if the user has an authentication agent, and if so, tries to
 * authenticate using the agent.
 */
static int
try_agent_authentication(struct ssh *ssh)
{
    int r, type, agent_fd, ret = 0;
    u_char response[16];
    size_t i;
    BIGNUM *challenge;
    struct ssh_identitylist *idlist = NULL;

    /* Get connection to the agent. */
    if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) {
        if (r != SSH_ERR_AGENT_NOT_PRESENT)
            debug("%s: ssh_get_authentication_socket: %s",
                  __func__, ssh_err(r));
        return 0;
    }

    if ((challenge = BN_new()) == NULL)
        fatal("try_agent_authentication: BN_new failed");

    /* Loop through identities served by the agent. */
    if ((r = ssh_fetch_identitylist(agent_fd, 1, &idlist)) != 0) {
        if (r != SSH_ERR_AGENT_NO_IDENTITIES)
            debug("%s: ssh_fetch_identitylist: %s",
                  __func__, ssh_err(r));
        goto out;
    }
    for (i = 0; i < idlist->nkeys; i++) {
        /* Try this identity. */
        debug("Trying RSA authentication via agent with '%.100s'",
              idlist->comments[i]);

        /*
         * Tell the server that we are willing to authenticate
         * using this key.
         */
        if ((r = sshpkt_start(ssh, SSH_CMSG_AUTH_RSA)) != 0 ||
                (r = sshpkt_put_bignum1(ssh, idlist->keys[i]->rsa->n)) != 0 ||
                (r = sshpkt_send(ssh)) != 0)
            fatal("%s: %s", __func__, ssh_err(r));
        ssh_packet_write_wait(ssh);

        /* Wait for server's response. */
        type = ssh_packet_read(ssh);

        /* The server sends failure if it doesn't like our key or
           does not support RSA authentication. */
        if (type == SSH_SMSG_FAILURE) {
            debug("Server refused our key.");
            continue;
        }
        /* Otherwise it should have sent a challenge. */
        if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
            ssh_packet_disconnect(ssh, "Protocol error during RSA "
                                  "authentication: %d", type);

        if ((r = sshpkt_get_bignum1(ssh, challenge)) != 0 ||
                (r = sshpkt_get_end(ssh)) != 0)
            fatal("%s: %s", __func__, ssh_err(r));

        debug("Received RSA challenge from server.");

        /* Ask the agent to decrypt the challenge. */
        if ((r = ssh_decrypt_challenge(agent_fd, idlist->keys[i],
                                       challenge, session_id, response)) != 0) {
            /*
             * The agent failed to authenticate this identifier
             * although it advertised it supports this.  Just
             * return a wrong value.
             */
            logit("Authentication agent failed to decrypt "
                  "challenge: %s", ssh_err(r));
            memset(response, 0, sizeof(response));
        }
        debug("Sending response to RSA challenge.");

        /* Send the decrypted challenge back to the server. */
        if ((r = sshpkt_start(ssh, SSH_CMSG_AUTH_RSA_RESPONSE)) != 0 ||
                (r = sshpkt_put(ssh, &response, sizeof(response))) != 0 ||
                (r = sshpkt_send(ssh)) != 0)
            fatal("%s: %s", __func__, ssh_err(r));
        ssh_packet_write_wait(ssh);

        /* Wait for response from the server. */
        type = ssh_packet_read(ssh);

        /*
         * The server returns success if it accepted the
         * authentication.
         */
        if (type == SSH_SMSG_SUCCESS) {
            debug("RSA authentication accepted by server.");
            ret = 1;
            break;
        } else if (type != SSH_SMSG_FAILURE)
            ssh_packet_disconnect(ssh, "Protocol error waiting RSA auth "
                                  "response: %d", type);
    }
    if (ret != 1)
        debug("RSA authentication using agent refused.");
out:
    ssh_free_identitylist(idlist);
    ssh_close_authentication_socket(agent_fd);
    BN_clear_free(challenge);
    return ret;
}
示例#28
0
static int
input_kex_ecdh_init(int type, u_int32_t seq, struct ssh *ssh)
{
	struct kex *kex = ssh->kex;
	EC_POINT *client_public;
	EC_KEY *server_key = NULL;
	const EC_GROUP *group;
	const EC_POINT *public_key;
	BIGNUM *shared_secret = NULL;
	struct sshkey *server_host_private, *server_host_public;
	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 ((server_key = EC_KEY_new_by_curve_name(kex->ec_nid)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if (EC_KEY_generate_key(server_key) != 1) {
		r = SSH_ERR_LIBCRYPTO_ERROR;
		goto out;
	}
	group = EC_KEY_get0_group(server_key);

#ifdef DEBUG_KEXECDH
	fputs("server private key:\n", stderr);
	sshkey_dump_ec_key(server_key);
#endif

	if (kex->load_host_public_key == NULL ||
	    kex->load_host_private_key == NULL) {
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}
	server_host_public = kex->load_host_public_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	server_host_private = kex->load_host_private_key(kex->hostkey_type,
	    kex->hostkey_nid, ssh);
	if (server_host_public == NULL) {
		r = SSH_ERR_NO_HOSTKEY_LOADED;
		goto out;
	}
	if ((client_public = EC_POINT_new(group)) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if ((r = sshpkt_get_ec(ssh, client_public, group)) != 0 ||
	    (r = sshpkt_get_end(ssh)) != 0)
		goto out;

#ifdef DEBUG_KEXECDH
	fputs("client public key:\n", stderr);
	sshkey_dump_ec_point(group, client_public);
#endif
	if (sshkey_ec_validate_public(group, client_public) != 0) {
		sshpkt_disconnect(ssh, "invalid client public key");
		r = SSH_ERR_MESSAGE_INCOMPLETE;
		goto out;
	}

	/* Calculate shared_secret */
	klen = (EC_GROUP_get_degree(group) + 7) / 8;
	if ((kbuf = malloc(klen)) == NULL ||
	    (shared_secret = BN_new()) == NULL) {
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	if (ECDH_compute_key(kbuf, klen, client_public,
	    server_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
	/* calc H */
	if ((r = sshkey_to_blob(server_host_public, &server_host_key_blob,
	    &sbloblen)) != 0)
		goto out;
	hashlen = sizeof(hash);
	if ((r = kex_ecdh_hash(
	    kex->hash_alg,
	    group,
	    kex->client_version_string,
	    kex->server_version_string,
	    sshbuf_ptr(kex->peer), sshbuf_len(kex->peer),
	    sshbuf_ptr(kex->my), sshbuf_len(kex->my),
	    server_host_key_blob, sbloblen,
	    client_public,
	    EC_KEY_get0_public_key(server_key),
	    shared_secret,
	    hash, &hashlen)) != 0)
		goto out;

	/* save session id := H */
	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);
	}

	/* sign H */
	if ((r = kex->sign(server_host_private, server_host_public, &signature,
	     &slen, hash, hashlen, kex->hostkey_alg, ssh->compat)) < 0)
		goto out;

	/* destroy_sensitive_data(); */

	public_key = EC_KEY_get0_public_key(server_key);
	/* send server hostkey, ECDH pubkey 'Q_S' and signed H */
	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_ECDH_REPLY)) != 0 ||
	    (r = sshpkt_put_string(ssh, server_host_key_blob, sbloblen)) != 0 ||
	    (r = sshpkt_put_ec(ssh, public_key, group)) != 0 ||
	    (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));
	if (kex->ec_client_key) {
		EC_KEY_free(kex->ec_client_key);
		kex->ec_client_key = NULL;
	}
	if (server_key)
		EC_KEY_free(server_key);
	if (kbuf) {
		explicit_bzero(kbuf, klen);
		free(kbuf);
	}
	if (shared_secret)
		BN_clear_free(shared_secret);
	free(server_host_key_blob);
	free(signature);
	return r;
}
示例#29
0
static int
input_kex_dh_gex_reply(int type, u_int32_t seq, struct ssh *ssh)
{
	Kex *kex = ssh->kex;
	BIGNUM *dh_server_pub = NULL, *shared_secret = NULL;
	struct sshkey *server_host_key;
	u_char *kbuf = NULL, *hash, *signature = NULL, *server_host_key_blob = NULL;
	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 (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 */
	if ((r = kexgex_hash(
	    kex->evp_md,
	    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(ssh, hash, hashlen, shared_secret)) == 0)
		r = kex_send_newkeys(ssh);
 out:
	DH_free(kex->dh);
	kex->dh = NULL;
	if (server_host_key_blob)
		free(server_host_key_blob);
	if (server_host_key)
		sshkey_free(server_host_key);
	if (dh_server_pub)
		BN_clear_free(dh_server_pub);
	if (kbuf) {
		bzero(kbuf, klen);
		free(kbuf);
	}
	if (shared_secret)
		BN_clear_free(shared_secret);
	if (signature)
		free(signature);
	return r;
}
示例#30
0
static int
input_kex_dh_gex_request(int type, u_int32_t seq, struct ssh *ssh)
{
	Kex *kex = ssh->kex;
	int r, min = -1, max = -1, nbits = -1;

	switch (type) {
	case SSH2_MSG_KEX_DH_GEX_REQUEST:
		debug("SSH2_MSG_KEX_DH_GEX_REQUEST received");
		if ((r = sshpkt_get_u32(ssh, &min)) != 0 ||
		    (r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
		    (r = sshpkt_get_u32(ssh, &max)) != 0 ||
		    (r = sshpkt_get_end(ssh)) != 0)
			goto out;
		kex->nbits = nbits;
		kex->min = min;
		kex->max = max;
		min = MAX(DH_GRP_MIN, min);
		max = MIN(DH_GRP_MAX, max);
		nbits = MAX(DH_GRP_MIN, nbits);
		nbits = MIN(DH_GRP_MAX, nbits);
		break;
	case SSH2_MSG_KEX_DH_GEX_REQUEST_OLD:
		debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD received");
		if ((r = sshpkt_get_u32(ssh, &nbits)) != 0 ||
		    (r = sshpkt_get_end(ssh)) != 0)
			goto out;
		kex->nbits = nbits;
		/* unused for old GEX */
		kex->min = min = DH_GRP_MIN;
		kex->max = max = DH_GRP_MAX;
		break;
	default:
		r = SSH_ERR_INVALID_ARGUMENT;
		goto out;
	}

	if (kex->max < kex->min || kex->nbits < kex->min ||
	    kex->max < kex->nbits) {
		r = SSH_ERR_DH_GEX_OUT_OF_RANGE;
		goto out;
	}

	/* Contact privileged parent */
	kex->dh = PRIVSEP(choose_dh(min, nbits, max));
	if (kex->dh == NULL) {
		sshpkt_disconnect(ssh, "no matching DH grp found");
		r = SSH_ERR_ALLOC_FAIL;
		goto out;
	}
	debug("SSH2_MSG_KEX_DH_GEX_GROUP sent");
	if ((r = sshpkt_start(ssh, SSH2_MSG_KEX_DH_GEX_GROUP)) != 0 ||
	    (r = sshpkt_put_bignum2(ssh, kex->dh->p)) != 0 ||
	    (r = sshpkt_put_bignum2(ssh, kex->dh->g)) != 0 ||
	    (r = sshpkt_send(ssh)) != 0)
		goto out;

	/* Compute our exchange value in parallel with the client */
	if ((r = dh_gen_key(kex->dh, kex->we_need * 8)) != 0)
		goto out;

	/* old KEX does not use min/max in kexgex_hash() */
	if (type == SSH2_MSG_KEX_DH_GEX_REQUEST_OLD)
		kex->min = kex->max = -1;

	debug("expecting SSH2_MSG_KEX_DH_GEX_INIT");
	ssh_dispatch_set(ssh, SSH2_MSG_KEX_DH_GEX_INIT, &input_kex_dh_gex_init);
	r = 0;
 out:
	return r;
}