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authorAlberto Gonzalez Iniesta <agi@inittab.org>2012-11-05 16:28:09 +0100
committerAlberto Gonzalez Iniesta <agi@inittab.org>2012-11-05 16:28:09 +0100
commit8dd0350e1607aa30f7a043c8d5ec7a7eeb874115 (patch)
tree566d0620eb693320cb121dfd93a5675fa704a30b /src/openvpn/ssl.c
parent349cfa7acb95abe865209a28e417ec74b56f9bba (diff)
Imported Upstream version 2.3_rc1
Diffstat (limited to 'src/openvpn/ssl.c')
-rw-r--r--src/openvpn/ssl.c3384
1 files changed, 3384 insertions, 0 deletions
diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
new file mode 100644
index 0000000..19512c0
--- /dev/null
+++ b/src/openvpn/ssl.c
@@ -0,0 +1,3384 @@
+/*
+ * OpenVPN -- An application to securely tunnel IP networks
+ * over a single TCP/UDP port, with support for SSL/TLS-based
+ * session authentication and key exchange,
+ * packet encryption, packet authentication, and
+ * packet compression.
+ *
+ * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
+ * Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com>
+ *
+ * Additions for eurephia plugin done by:
+ * David Sommerseth <dazo@users.sourceforge.net> Copyright (C) 2008-2009
+ *
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (see the file COPYING included with this
+ * distribution); if not, write to the Free Software Foundation, Inc.,
+ * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+/**
+ * @file Control Channel SSL/Data channel negotiation Module
+ */
+
+/*
+ * The routines in this file deal with dynamically negotiating
+ * the data channel HMAC and cipher keys through a TLS session.
+ *
+ * Both the TLS session and the data channel are multiplexed
+ * over the same TCP/UDP port.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#elif defined(_MSC_VER)
+#include "config-msvc.h"
+#endif
+
+#include "syshead.h"
+
+#if defined(ENABLE_CRYPTO) && defined(ENABLE_SSL)
+
+#include "error.h"
+#include "common.h"
+#include "integer.h"
+#include "socket.h"
+#include "misc.h"
+#include "fdmisc.h"
+#include "interval.h"
+#include "perf.h"
+#include "status.h"
+#include "gremlin.h"
+#include "pkcs11.h"
+#include "list.h"
+#include "base64.h"
+#include "route.h"
+
+#include "ssl.h"
+#include "ssl_verify.h"
+#include "ssl_backend.h"
+
+#include "memdbg.h"
+
+#ifndef ENABLE_OCC
+static const char ssl_default_options_string[] = "V0 UNDEF";
+#endif
+
+static inline const char *
+local_options_string (const struct tls_session *session)
+{
+#ifdef ENABLE_OCC
+ return session->opt->local_options;
+#else
+ return ssl_default_options_string;
+#endif
+}
+
+#ifdef MEASURE_TLS_HANDSHAKE_STATS
+
+static int tls_handshake_success; /* GLOBAL */
+static int tls_handshake_error; /* GLOBAL */
+static int tls_packets_generated; /* GLOBAL */
+static int tls_packets_sent; /* GLOBAL */
+
+#define INCR_SENT ++tls_packets_sent
+#define INCR_GENERATED ++tls_packets_generated
+#define INCR_SUCCESS ++tls_handshake_success
+#define INCR_ERROR ++tls_handshake_error
+
+void
+show_tls_performance_stats(void)
+{
+ msg (D_TLS_DEBUG_LOW, "TLS Handshakes, success=%f%% (good=%d, bad=%d), retransmits=%f%%",
+ (double) tls_handshake_success / (tls_handshake_success + tls_handshake_error) * 100.0,
+ tls_handshake_success, tls_handshake_error,
+ (double) (tls_packets_sent - tls_packets_generated) / tls_packets_generated * 100.0);
+}
+#else
+
+#define INCR_SENT
+#define INCR_GENERATED
+#define INCR_SUCCESS
+#define INCR_ERROR
+
+#endif
+
+
+/*
+ * Max number of bytes we will add
+ * for data structures common to both
+ * data and control channel packets.
+ * (opcode only).
+ */
+void
+tls_adjust_frame_parameters(struct frame *frame)
+{
+ frame_add_to_extra_frame (frame, 1); /* space for opcode */
+}
+
+/*
+ * Max number of bytes we will add
+ * to control channel packet.
+ */
+static void
+tls_init_control_channel_frame_parameters(const struct frame *data_channel_frame,
+ struct frame *frame)
+{
+ /*
+ * frame->extra_frame is already initialized with tls_auth buffer requirements,
+ * if --tls-auth is enabled.
+ */
+
+ /* inherit link MTU and extra_link from data channel */
+ frame->link_mtu = data_channel_frame->link_mtu;
+ frame->extra_link = data_channel_frame->extra_link;
+
+ /* set extra_frame */
+ tls_adjust_frame_parameters (frame);
+ reliable_ack_adjust_frame_parameters (frame, CONTROL_SEND_ACK_MAX);
+ frame_add_to_extra_frame (frame, SID_SIZE + sizeof (packet_id_type));
+
+ /* set dynamic link MTU to minimum value */
+ frame_set_mtu_dynamic (frame, 0, SET_MTU_TUN);
+}
+
+void
+init_ssl_lib ()
+{
+ tls_init_lib ();
+
+ crypto_init_lib ();
+}
+
+void
+free_ssl_lib ()
+{
+ crypto_uninit_lib ();
+ prng_uninit();
+
+ tls_free_lib();
+}
+
+/*
+ * OpenSSL library calls pem_password_callback if the
+ * private key is protected by a password.
+ */
+
+static struct user_pass passbuf; /* GLOBAL */
+
+void
+pem_password_setup (const char *auth_file)
+{
+ if (!strlen (passbuf.password))
+ get_user_pass (&passbuf, auth_file, UP_TYPE_PRIVATE_KEY, GET_USER_PASS_MANAGEMENT|GET_USER_PASS_SENSITIVE|GET_USER_PASS_PASSWORD_ONLY);
+}
+
+int
+pem_password_callback (char *buf, int size, int rwflag, void *u)
+{
+ if (buf)
+ {
+ /* prompt for password even if --askpass wasn't specified */
+ pem_password_setup (NULL);
+ strncpynt (buf, passbuf.password, size);
+ purge_user_pass (&passbuf, false);
+
+ return strlen (buf);
+ }
+ return 0;
+}
+
+/*
+ * Auth username/password handling
+ */
+
+static bool auth_user_pass_enabled; /* GLOBAL */
+static struct user_pass auth_user_pass; /* GLOBAL */
+
+#ifdef ENABLE_CLIENT_CR
+static char *auth_challenge; /* GLOBAL */
+#endif
+
+void
+auth_user_pass_setup (const char *auth_file, const struct static_challenge_info *sci)
+{
+ auth_user_pass_enabled = true;
+ if (!auth_user_pass.defined)
+ {
+#if AUTO_USERID
+ get_user_pass_auto_userid (&auth_user_pass, auth_file);
+#else
+# ifdef ENABLE_CLIENT_CR
+ if (auth_challenge) /* dynamic challenge/response */
+ get_user_pass_cr (&auth_user_pass,
+ auth_file,
+ UP_TYPE_AUTH,
+ GET_USER_PASS_MANAGEMENT|GET_USER_PASS_SENSITIVE|GET_USER_PASS_DYNAMIC_CHALLENGE,
+ auth_challenge);
+ else if (sci) /* static challenge response */
+ {
+ int flags = GET_USER_PASS_MANAGEMENT|GET_USER_PASS_SENSITIVE|GET_USER_PASS_STATIC_CHALLENGE;
+ if (sci->flags & SC_ECHO)
+ flags |= GET_USER_PASS_STATIC_CHALLENGE_ECHO;
+ get_user_pass_cr (&auth_user_pass,
+ auth_file,
+ UP_TYPE_AUTH,
+ flags,
+ sci->challenge_text);
+ }
+ else
+# endif
+ get_user_pass (&auth_user_pass, auth_file, UP_TYPE_AUTH, GET_USER_PASS_MANAGEMENT|GET_USER_PASS_SENSITIVE);
+#endif
+ }
+}
+
+/*
+ * Disable password caching
+ */
+void
+ssl_set_auth_nocache (void)
+{
+ passbuf.nocache = true;
+ auth_user_pass.nocache = true;
+}
+
+/*
+ * Set an authentication token
+ */
+void
+ssl_set_auth_token (const char *token)
+{
+ set_auth_token (&auth_user_pass, token);
+}
+
+/*
+ * Forget private key password AND auth-user-pass username/password.
+ */
+void
+ssl_purge_auth (const bool auth_user_pass_only)
+{
+ if (!auth_user_pass_only)
+ {
+#ifdef ENABLE_PKCS11
+ pkcs11_logout ();
+#endif
+ purge_user_pass (&passbuf, true);
+ }
+ purge_user_pass (&auth_user_pass, true);
+#ifdef ENABLE_CLIENT_CR
+ ssl_purge_auth_challenge();
+#endif
+}
+
+#ifdef ENABLE_CLIENT_CR
+
+void
+ssl_purge_auth_challenge (void)
+{
+ free (auth_challenge);
+ auth_challenge = NULL;
+}
+
+void
+ssl_put_auth_challenge (const char *cr_str)
+{
+ ssl_purge_auth_challenge();
+ auth_challenge = string_alloc(cr_str, NULL);
+}
+
+#endif
+
+/*
+ * Initialize SSL context.
+ * All files are in PEM format.
+ */
+void
+init_ssl (const struct options *options, struct tls_root_ctx *new_ctx)
+{
+ ASSERT(NULL != new_ctx);
+
+ tls_clear_error();
+
+ if (options->tls_server)
+ {
+ tls_ctx_server_new(new_ctx);
+ tls_ctx_load_dh_params(new_ctx, options->dh_file, options->dh_file_inline);
+ }
+ else /* if client */
+ {
+ tls_ctx_client_new(new_ctx);
+ }
+
+ tls_ctx_set_options(new_ctx, options->ssl_flags);
+
+ if (options->pkcs12_file)
+ {
+ if (0 != tls_ctx_load_pkcs12(new_ctx, options->pkcs12_file,
+ options->pkcs12_file_inline, !options->ca_file))
+ goto err;
+ }
+#ifdef ENABLE_PKCS11
+ else if (options->pkcs11_providers[0])
+ {
+ if (!tls_ctx_use_pkcs11 (new_ctx, options->pkcs11_id_management, options->pkcs11_id))
+ {
+ msg (M_WARN, "Cannot load certificate \"%s\" using PKCS#11 interface",
+ options->pkcs11_id);
+ goto err;
+ }
+ }
+#endif
+#ifdef ENABLE_CRYPTOAPI
+ else if (options->cryptoapi_cert)
+ {
+ tls_ctx_load_cryptoapi(new_ctx, options->cryptoapi_cert);
+ }
+#endif
+#ifdef MANAGMENT_EXTERNAL_KEY
+ else if ((options->management_flags & MF_EXTERNAL_KEY) && options->cert_file)
+ {
+ openvpn_x509_cert_t *my_cert = NULL;
+ tls_ctx_load_cert_file(new_ctx, options->cert_file, options->cert_file_inline,
+ &my_cert);
+ tls_ctx_use_external_private_key(new_ctx, my_cert);
+
+ tls_ctx_free_cert_file(my_cert);
+ }
+#endif
+ else
+ {
+ /* Load Certificate */
+ if (options->cert_file)
+ {
+ tls_ctx_load_cert_file(new_ctx, options->cert_file, options->cert_file_inline, NULL);
+ }
+
+ /* Load Private Key */
+ if (options->priv_key_file)
+ {
+ if (0 != tls_ctx_load_priv_file(new_ctx, options->priv_key_file, options->priv_key_file_inline))
+ goto err;
+ }
+ }
+
+ if (options->ca_file || options->ca_path)
+ {
+ tls_ctx_load_ca(new_ctx, options->ca_file, options->ca_file_inline,
+ options->ca_path, options->tls_server);
+ }
+
+ /* Load extra certificates that are part of our own certificate
+ chain but shouldn't be included in the verify chain */
+ if (options->extra_certs_file || options->extra_certs_file_inline)
+ {
+ tls_ctx_load_extra_certs(new_ctx, options->extra_certs_file, options->extra_certs_file_inline);
+ }
+
+ /* Allowable ciphers */
+ if (options->cipher_list)
+ {
+ tls_ctx_restrict_ciphers(new_ctx, options->cipher_list);
+ }
+
+#ifdef ENABLE_CRYPTO_POLARSSL
+ /* Personalise the random by mixing in the certificate */
+ tls_ctx_personalise_random (new_ctx);
+#endif
+
+ tls_clear_error ();
+ return;
+
+ err:
+ tls_clear_error ();
+ tls_ctx_free (new_ctx);
+ return;
+}
+
+/*
+ * Map internal constants to ascii names.
+ */
+static const char *
+state_name (int state)
+{
+ switch (state)
+ {
+ case S_UNDEF:
+ return "S_UNDEF";
+ case S_INITIAL:
+ return "S_INITIAL";
+ case S_PRE_START:
+ return "S_PRE_START";
+ case S_START:
+ return "S_START";
+ case S_SENT_KEY:
+ return "S_SENT_KEY";
+ case S_GOT_KEY:
+ return "S_GOT_KEY";
+ case S_ACTIVE:
+ return "S_ACTIVE";
+ case S_NORMAL_OP:
+ return "S_NORMAL_OP";
+ case S_ERROR:
+ return "S_ERROR";
+ default:
+ return "S_???";
+ }
+}
+
+static const char *
+packet_opcode_name (int op)
+{
+ switch (op)
+ {
+ case P_CONTROL_HARD_RESET_CLIENT_V1:
+ return "P_CONTROL_HARD_RESET_CLIENT_V1";
+ case P_CONTROL_HARD_RESET_SERVER_V1:
+ return "P_CONTROL_HARD_RESET_SERVER_V1";
+ case P_CONTROL_HARD_RESET_CLIENT_V2:
+ return "P_CONTROL_HARD_RESET_CLIENT_V2";
+ case P_CONTROL_HARD_RESET_SERVER_V2:
+ return "P_CONTROL_HARD_RESET_SERVER_V2";
+ case P_CONTROL_SOFT_RESET_V1:
+ return "P_CONTROL_SOFT_RESET_V1";
+ case P_CONTROL_V1:
+ return "P_CONTROL_V1";
+ case P_ACK_V1:
+ return "P_ACK_V1";
+ case P_DATA_V1:
+ return "P_DATA_V1";
+ default:
+ return "P_???";
+ }
+}
+
+static const char *
+session_index_name (int index)
+{
+ switch (index)
+ {
+ case TM_ACTIVE:
+ return "TM_ACTIVE";
+ case TM_UNTRUSTED:
+ return "TM_UNTRUSTED";
+ case TM_LAME_DUCK:
+ return "TM_LAME_DUCK";
+ default:
+ return "TM_???";
+ }
+}
+
+/*
+ * For debugging.
+ */
+static const char *
+print_key_id (struct tls_multi *multi, struct gc_arena *gc)
+{
+ int i;
+ struct buffer out = alloc_buf_gc (256, gc);
+
+ for (i = 0; i < KEY_SCAN_SIZE; ++i)
+ {
+ struct key_state *ks = multi->key_scan[i];
+ buf_printf (&out, " [key#%d state=%s id=%d sid=%s]", i,
+ state_name (ks->state), ks->key_id,
+ session_id_print (&ks->session_id_remote, gc));
+ }
+
+ return BSTR (&out);
+}
+
+/*
+ * Given a key_method, return true if op
+ * represents the required form of hard_reset.
+ *
+ * If key_method = 0, return true if any
+ * form of hard reset is used.
+ */
+static bool
+is_hard_reset (int op, int key_method)
+{
+ if (!key_method || key_method == 1)
+ if (op == P_CONTROL_HARD_RESET_CLIENT_V1 || op == P_CONTROL_HARD_RESET_SERVER_V1)
+ return true;
+
+ if (!key_method || key_method >= 2)
+ if (op == P_CONTROL_HARD_RESET_CLIENT_V2 || op == P_CONTROL_HARD_RESET_SERVER_V2)
+ return true;
+
+ return false;
+}
+
+/** @addtogroup control_processor
+ * @{ */
+
+/** @name Functions for initialization and cleanup of key_state structures
+ * @{ */
+
+/**
+ * Initialize a \c key_state structure.
+ * @ingroup control_processor
+ *
+ * This function initializes a \c key_state structure associated with a \c
+ * tls_session. It sets up the structure's SSL-BIO, sets the object's \c
+ * key_state.state to \c S_INITIAL, and sets the session ID and key ID two
+ * appropriate values based on the \c tls_session's internal state. It
+ * also initializes a new set of structures for the \link reliable
+ * Reliability Layer\endlink.
+ *
+ * @param session - A pointer to the \c tls_session structure
+ * associated with the \a ks argument.
+ * @param ks - A pointer to the \c key_state structure to be
+ * initialized. This structure should already have
+ * been allocated before calling this function.
+ */
+static void
+key_state_init (struct tls_session *session, struct key_state *ks)
+{
+ update_time ();
+
+ CLEAR (*ks);
+
+ /*
+ * Build TLS object that reads/writes ciphertext
+ * to/from memory BIOs.
+ */
+ key_state_ssl_init(&ks->ks_ssl, &session->opt->ssl_ctx, session->opt->server,
+ session);
+
+ /* Set control-channel initiation mode */
+ ks->initial_opcode = session->initial_opcode;
+ session->initial_opcode = P_CONTROL_SOFT_RESET_V1;
+ ks->state = S_INITIAL;
+ ks->key_id = session->key_id;
+
+ /*
+ * key_id increments to KEY_ID_MASK then recycles back to 1.
+ * This way you know that if key_id is 0, it is the first key.
+ */
+ ++session->key_id;
+ session->key_id &= P_KEY_ID_MASK;
+ if (!session->key_id)
+ session->key_id = 1;
+
+ /* allocate key source material object */
+ ALLOC_OBJ_CLEAR (ks->key_src, struct key_source2);
+
+ /* allocate reliability objects */
+ ALLOC_OBJ_CLEAR (ks->send_reliable, struct reliable);
+ ALLOC_OBJ_CLEAR (ks->rec_reliable, struct reliable);
+ ALLOC_OBJ_CLEAR (ks->rec_ack, struct reliable_ack);
+
+ /* allocate buffers */
+ ks->plaintext_read_buf = alloc_buf (TLS_CHANNEL_BUF_SIZE);
+ ks->plaintext_write_buf = alloc_buf (TLS_CHANNEL_BUF_SIZE);
+ ks->ack_write_buf = alloc_buf (BUF_SIZE (&session->opt->frame));
+ reliable_init (ks->send_reliable, BUF_SIZE (&session->opt->frame),
+ FRAME_HEADROOM (&session->opt->frame), TLS_RELIABLE_N_SEND_BUFFERS,
+ ks->key_id ? false : session->opt->xmit_hold);
+ reliable_init (ks->rec_reliable, BUF_SIZE (&session->opt->frame),
+ FRAME_HEADROOM (&session->opt->frame), TLS_RELIABLE_N_REC_BUFFERS,
+ false);
+ reliable_set_timeout (ks->send_reliable, session->opt->packet_timeout);
+
+ /* init packet ID tracker */
+ packet_id_init (&ks->packet_id,
+ session->opt->tcp_mode,
+ session->opt->replay_window,
+ session->opt->replay_time,
+ "SSL", ks->key_id);
+
+#ifdef MANAGEMENT_DEF_AUTH
+ ks->mda_key_id = session->opt->mda_context->mda_key_id_counter++;
+#endif
+}
+
+
+/**
+ * Cleanup a \c key_state structure.
+ * @ingroup control_processor
+ *
+ * This function cleans up a \c key_state structure. It frees the
+ * associated SSL-BIO, and the structures allocated for the \link reliable
+ * Reliability Layer\endlink.
+ *
+ * @param ks - A pointer to the \c key_state structure to be
+ * cleaned up.
+ * @param clear - Whether the memory allocated for the \a ks object
+ * should be overwritten with 0s.
+ */
+static void
+key_state_free (struct key_state *ks, bool clear)
+{
+ ks->state = S_UNDEF;
+
+ key_state_ssl_free(&ks->ks_ssl);
+
+ free_key_ctx_bi (&ks->key);
+ free_buf (&ks->plaintext_read_buf);
+ free_buf (&ks->plaintext_write_buf);
+ free_buf (&ks->ack_write_buf);
+ buffer_list_free(ks->paybuf);
+
+ if (ks->send_reliable)
+ {
+ reliable_free (ks->send_reliable);
+ free (ks->send_reliable);
+ }
+
+ if (ks->rec_reliable)
+ {
+ reliable_free (ks->rec_reliable);
+ free (ks->rec_reliable);
+ }
+
+ if (ks->rec_ack)
+ free (ks->rec_ack);
+
+ if (ks->key_src)
+ free (ks->key_src);
+
+ packet_id_free (&ks->packet_id);
+
+#ifdef PLUGIN_DEF_AUTH
+ key_state_rm_auth_control_file (ks);
+#endif
+
+ if (clear)
+ CLEAR (*ks);
+}
+
+/** @} name Functions for initialization and cleanup of key_state structures */
+
+/** @} addtogroup control_processor */
+
+
+/*
+ * Must be called if we move a tls_session in memory.
+ */
+static inline void tls_session_set_self_referential_pointers (struct tls_session* session) {
+ session->tls_auth.packet_id = &session->tls_auth_pid;
+}
+
+
+/** @addtogroup control_processor
+ * @{ */
+
+/** @name Functions for initialization and cleanup of tls_session structures
+ * @{ */
+
+/**
+ * Initialize a \c tls_session structure.
+ * @ingroup control_processor
+ *
+ * This function initializes a \c tls_session structure. This includes
+ * generating a random session ID, and initializing the \c KS_PRIMARY \c
+ * key_state in the \c tls_session.key array.
+ *
+ * @param multi - A pointer to the \c tls_multi structure
+ * associated with the \a session argument.
+ * @param session - A pointer to the \c tls_session structure to be
+ * initialized. This structure should already have
+ * been allocated before calling this function.
+ */
+static void
+tls_session_init (struct tls_multi *multi, struct tls_session *session)
+{
+ struct gc_arena gc = gc_new ();
+
+ dmsg (D_TLS_DEBUG, "TLS: tls_session_init: entry");
+
+ CLEAR (*session);
+
+ /* Set options data to point to parent's option structure */
+ session->opt = &multi->opt;
+
+ /* Randomize session # if it is 0 */
+ while (!session_id_defined(&session->session_id))
+ session_id_random (&session->session_id);
+
+ /* Are we a TLS server or client? */
+ ASSERT (session->opt->key_method >= 1);
+ if (session->opt->key_method == 1)
+ {
+ session->initial_opcode = session->opt->server ?
+ P_CONTROL_HARD_RESET_SERVER_V1 : P_CONTROL_HARD_RESET_CLIENT_V1;
+ }
+ else /* session->opt->key_method >= 2 */
+ {
+ session->initial_opcode = session->opt->server ?
+ P_CONTROL_HARD_RESET_SERVER_V2 : P_CONTROL_HARD_RESET_CLIENT_V2;
+ }
+
+ /* Initialize control channel authentication parameters */
+ session->tls_auth = session->opt->tls_auth;
+
+ /* Set session internal pointers (also called if session object is moved in memory) */
+ tls_session_set_self_referential_pointers (session);
+
+ /* initialize packet ID replay window for --tls-auth */
+ packet_id_init (session->tls_auth.packet_id,
+ session->opt->tcp_mode,
+ session->opt->replay_window,
+ session->opt->replay_time,
+ "TLS_AUTH", session->key_id);
+
+ /* load most recent packet-id to replay protect on --tls-auth */
+ packet_id_persist_load_obj (session->tls_auth.pid_persist, session->tls_auth.packet_id);
+
+ key_state_init (session, &session->key[KS_PRIMARY]);
+
+ dmsg (D_TLS_DEBUG, "TLS: tls_session_init: new session object, sid=%s",
+ session_id_print (&session->session_id, &gc));
+
+ gc_free (&gc);
+}
+
+/**
+ * Clean up a \c tls_session structure.
+ * @ingroup control_processor
+ *
+ * This function cleans up a \c tls_session structure. This includes
+ * cleaning up all associated \c key_state structures.
+ *
+ * @param session - A pointer to the \c tls_session structure to be
+ * cleaned up.
+ * @param clear - Whether the memory allocated for the \a session
+ * object should be overwritten with 0s.
+ */
+static void
+tls_session_free (struct tls_session *session, bool clear)
+{
+ int i;
+
+ if (session->tls_auth.packet_id)
+ packet_id_free (session->tls_auth.packet_id);
+
+ for (i = 0; i < KS_SIZE; ++i)
+ key_state_free (&session->key[i], false);
+
+ if (session->common_name)
+ free (session->common_name);
+
+ cert_hash_free (session->cert_hash_set);
+
+ if (clear)
+ CLEAR (*session);
+}
+
+/** @} name Functions for initialization and cleanup of tls_session structures */
+
+/** @} addtogroup control_processor */
+
+
+static void
+move_session (struct tls_multi* multi, int dest, int src, bool reinit_src)
+{
+ msg (D_TLS_DEBUG_LOW, "TLS: move_session: dest=%s src=%s reinit_src=%d",
+ session_index_name(dest),
+ session_index_name(src),
+ reinit_src);
+ ASSERT (src != dest);
+ ASSERT (src >= 0 && src < TM_SIZE);
+ ASSERT (dest >= 0 && dest < TM_SIZE);
+ tls_session_free (&multi->session[dest], false);
+ multi->session[dest] = multi->session[src];
+ tls_session_set_self_referential_pointers (&multi->session[dest]);
+
+ if (reinit_src)
+ tls_session_init (multi, &multi->session[src]);
+ else
+ CLEAR (multi->session[src]);
+
+ dmsg (D_TLS_DEBUG, "TLS: move_session: exit");
+}
+
+static void
+reset_session (struct tls_multi *multi, struct tls_session *session)
+{
+ tls_session_free (session, false);
+ tls_session_init (multi, session);
+}
+
+#if 0
+/*
+ * Transmit a TLS reset on our untrusted channel.
+ */
+static void
+initiate_untrusted_session (struct tls_multi *multi, struct sockaddr_in *to)
+{
+ struct tls_session *session = &multi->session[TM_UNTRUSTED];
+ struct key_state *ks = &session->key[KS_PRIMARY];
+
+ reset_session (multi, session);
+ ks->remote_addr = *to;
+ msg (D_TLS_DEBUG_LOW, "TLS: initiate_untrusted_session: addr=%s", print_sockaddr (to));
+}
+#endif
+
+/*
+ * Used to determine in how many seconds we should be
+ * called again.
+ */
+static inline void
+compute_earliest_wakeup (interval_t *earliest, interval_t seconds_from_now) {
+ if (seconds_from_now < *earliest)
+ *earliest = seconds_from_now;
+ if (*earliest < 0)
+ *earliest = 0;
+}
+
+/*
+ * Return true if "lame duck" or retiring key has expired and can
+ * no longer be used.
+ */
+static inline bool
+lame_duck_must_die (const struct tls_session* session, interval_t *wakeup)
+{
+ const struct key_state* lame = &session->key[KS_LAME_DUCK];
+ if (lame->state >= S_INITIAL)
+ {
+ const time_t local_now = now;
+ ASSERT (lame->must_die); /* a lame duck key must always have an expiration */
+ if (local_now < lame->must_die)
+ {
+ compute_earliest_wakeup (wakeup, lame->must_die - local_now);
+ return false;
+ }
+ else
+ return true;
+ }
+ else if (lame->state == S_ERROR)
+ return true;
+ else
+ return false;
+}
+
+struct tls_multi *
+tls_multi_init (struct tls_options *tls_options)
+{
+ struct tls_multi *ret;
+
+ ALLOC_OBJ_CLEAR (ret, struct tls_multi);
+
+ /* get command line derived options */
+ ret->opt = *tls_options;
+
+ /* set up pointer to HMAC object for TLS packet authentication */
+ ret->opt.tls_auth.key_ctx_bi = &ret->opt.tls_auth_key;
+
+ /* set up list of keys to be scanned by data channel encrypt and decrypt routines */
+ ASSERT (SIZE (ret->key_scan) == 3);
+ ret->key_scan[0] = &ret->session[TM_ACTIVE].key[KS_PRIMARY];
+ ret->key_scan[1] = &ret->session[TM_ACTIVE].key[KS_LAME_DUCK];
+ ret->key_scan[2] = &ret->session[TM_LAME_DUCK].key[KS_LAME_DUCK];
+
+ return ret;
+}
+
+void
+tls_multi_init_finalize (struct tls_multi* multi, const struct frame* frame)
+{
+ tls_init_control_channel_frame_parameters (frame, &multi->opt.frame);
+
+ /* initialize the active and untrusted sessions */
+
+ tls_session_init (multi, &multi->session[TM_ACTIVE]);
+
+ if (!multi->opt.single_session)
+ tls_session_init (multi, &multi->session[TM_UNTRUSTED]);
+}
+
+/*
+ * Initialize and finalize a standalone tls-auth verification object.
+ */
+
+struct tls_auth_standalone *
+tls_auth_standalone_init (struct tls_options *tls_options,
+ struct gc_arena *gc)
+{
+ struct tls_auth_standalone *tas;
+
+ ALLOC_OBJ_CLEAR_GC (tas, struct tls_auth_standalone, gc);
+
+ /* set up pointer to HMAC object for TLS packet authentication */
+ tas->tls_auth_key = tls_options->tls_auth_key;
+ tas->tls_auth_options.key_ctx_bi = &tas->tls_auth_key;
+ tas->tls_auth_options.flags |= CO_PACKET_ID_LONG_FORM;
+
+ /* get initial frame parms, still need to finalize */
+ tas->frame = tls_options->frame;
+
+ return tas;
+}
+
+void
+tls_auth_standalone_finalize (struct tls_auth_standalone *tas,
+ const struct frame *frame)
+{
+ tls_init_control_channel_frame_parameters (frame, &tas->frame);
+}
+
+/*
+ * Set local and remote option compatibility strings.
+ * Used to verify compatibility of local and remote option
+ * sets.
+ */
+void
+tls_multi_init_set_options (struct tls_multi* multi,
+ const char *local,
+ const char *remote)
+{
+#ifdef ENABLE_OCC
+ /* initialize options string */
+ multi->opt.local_options = local;
+ multi->opt.remote_options = remote;
+#endif
+}
+
+/*
+ * Cleanup a tls_multi structure and free associated memory allocations.
+ */
+void
+tls_multi_free (struct tls_multi *multi, bool clear)
+{
+ int i;
+
+ ASSERT (multi);
+
+#ifdef MANAGEMENT_DEF_AUTH
+ man_def_auth_set_client_reason(multi, NULL);
+
+ free (multi->peer_info);
+#endif
+
+ if (multi->locked_cn)
+ free (multi->locked_cn);
+
+ if (multi->locked_username)
+ free (multi->locked_username);
+
+ cert_hash_free (multi->locked_cert_hash_set);
+
+ for (i = 0; i < TM_SIZE; ++i)
+ tls_session_free (&multi->session[i], false);
+
+ if (clear)
+ CLEAR (*multi);
+
+ free(multi);
+}
+
+
+/*
+ * Move a packet authentication HMAC + related fields to or from the front
+ * of the buffer so it can be processed by encrypt/decrypt.
+ */
+
+/*
+ * Dependent on hmac size, opcode size, and session_id size.
+ * Will assert if too small.
+ */
+#define SWAP_BUF_SIZE 256
+
+static bool
+swap_hmac (struct buffer *buf, const struct crypto_options *co, bool incoming)
+{
+ struct key_ctx *ctx;
+
+ ASSERT (co);
+
+ ctx = (incoming ? &co->key_ctx_bi->decrypt : &co->key_ctx_bi->encrypt);
+ ASSERT (ctx->hmac);
+
+ {
+ /* hmac + packet_id (8 bytes) */
+ const int hmac_size = hmac_ctx_size (ctx->hmac) + packet_id_size (true);
+
+ /* opcode + session_id */
+ const int osid_size = 1 + SID_SIZE;
+
+ int e1, e2;
+ uint8_t *b = BPTR (buf);
+ uint8_t buf1[SWAP_BUF_SIZE];
+ uint8_t buf2[SWAP_BUF_SIZE];
+
+ if (incoming)
+ {
+ e1 = osid_size;
+ e2 = hmac_size;
+ }
+ else
+ {
+ e1 = hmac_size;
+ e2 = osid_size;
+ }
+
+ ASSERT (e1 <= SWAP_BUF_SIZE && e2 <= SWAP_BUF_SIZE);
+
+ if (buf->len >= e1 + e2)
+ {
+ memcpy (buf1, b, e1);
+ memcpy (buf2, b + e1, e2);
+ memcpy (b, buf2, e2);
+ memcpy (b + e2, buf1, e1);
+ return true;
+ }
+ else
+ return false;
+ }
+}
+
+#undef SWAP_BUF_SIZE
+
+/*
+ * Write a control channel authentication record.
+ */
+static void
+write_control_auth (struct tls_session *session,
+ struct key_state *ks,
+ struct buffer *buf,
+ struct link_socket_actual **to_link_addr,
+ int opcode,
+ int max_ack,
+ bool prepend_ack)
+{
+ uint8_t *header;
+ struct buffer null = clear_buf ();
+
+ ASSERT (link_socket_actual_defined (&ks->remote_addr));
+ ASSERT (reliable_ack_write
+ (ks->rec_ack, buf, &ks->session_id_remote, max_ack, prepend_ack));
+ ASSERT (session_id_write_prepend (&session->session_id, buf));
+ ASSERT (header = buf_prepend (buf, 1));
+ *header = ks->key_id | (opcode << P_OPCODE_SHIFT);
+ if (session->tls_auth.key_ctx_bi->encrypt.hmac)
+ {
+ /* no encryption, only write hmac */
+ openvpn_encrypt (buf, null, &session->tls_auth, NULL);
+ ASSERT (swap_hmac (buf, &session->tls_auth, false));
+ }
+ *to_link_addr = &ks->remote_addr;
+}
+
+/*
+ * Read a control channel authentication record.
+ */
+static bool
+read_control_auth (struct buffer *buf,
+ const struct crypto_options *co,
+ const struct link_socket_actual *from)
+{
+ struct gc_arena gc = gc_new ();
+
+ if (co->key_ctx_bi->decrypt.hmac)
+ {
+ struct buffer null = clear_buf ();
+
+ /* move the hmac record to the front of the packet */
+ if (!swap_hmac (buf, co, true))
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: cannot locate HMAC in incoming packet from %s",
+ print_link_socket_actual (from, &gc));
+ gc_free (&gc);
+ return false;
+ }
+
+ /* authenticate only (no decrypt) and remove the hmac record
+ from the head of the buffer */
+ openvpn_decrypt (buf, null, co, NULL);
+ if (!buf->len)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: incoming packet authentication failed from %s",
+ print_link_socket_actual (from, &gc));
+ gc_free (&gc);
+ return false;
+ }
+
+ }
+
+ /* advance buffer pointer past opcode & session_id since our caller
+ already read it */
+ buf_advance (buf, SID_SIZE + 1);
+
+ gc_free (&gc);
+ return true;
+}
+
+/*
+ * For debugging, print contents of key_source2 structure.
+ */
+
+static void
+key_source_print (const struct key_source *k,
+ const char *prefix)
+{
+ struct gc_arena gc = gc_new ();
+
+ VALGRIND_MAKE_READABLE ((void *)k->pre_master, sizeof (k->pre_master));
+ VALGRIND_MAKE_READABLE ((void *)k->random1, sizeof (k->random1));
+ VALGRIND_MAKE_READABLE ((void *)k->random2, sizeof (k->random2));
+
+ dmsg (D_SHOW_KEY_SOURCE,
+ "%s pre_master: %s",
+ prefix,
+ format_hex (k->pre_master, sizeof (k->pre_master), 0, &gc));
+ dmsg (D_SHOW_KEY_SOURCE,
+ "%s random1: %s",
+ prefix,
+ format_hex (k->random1, sizeof (k->random1), 0, &gc));
+ dmsg (D_SHOW_KEY_SOURCE,
+ "%s random2: %s",
+ prefix,
+ format_hex (k->random2, sizeof (k->random2), 0, &gc));
+
+ gc_free (&gc);
+}
+
+static void
+key_source2_print (const struct key_source2 *k)
+{
+ key_source_print (&k->client, "Client");
+ key_source_print (&k->server, "Server");
+}
+
+/*
+ * Generate the hash required by for the \c tls1_PRF function.
+ *
+ * @param md_kt Message digest to use
+ * @param sec Secret to base the hash on
+ * @param sec_len Length of the secret
+ * @param seed Seed to hash
+ * @param seed_len Length of the seed
+ * @param out Output buffer
+ * @param olen Length of the output buffer
+ */
+void
+tls1_P_hash(const md_kt_t *md_kt,
+ const uint8_t *sec,
+ int sec_len,
+ const uint8_t *seed,
+ int seed_len,
+ uint8_t *out,
+ int olen)
+{
+ struct gc_arena gc = gc_new ();
+ int chunk,n;
+ hmac_ctx_t ctx;
+ hmac_ctx_t ctx_tmp;
+ uint8_t A1[MAX_HMAC_KEY_LENGTH];
+ unsigned int A1_len;
+
+#ifdef ENABLE_DEBUG
+ const int olen_orig = olen;
+ const uint8_t *out_orig = out;
+#endif
+
+ CLEAR(ctx);
+ CLEAR(ctx_tmp);
+
+ dmsg (D_SHOW_KEY_SOURCE, "tls1_P_hash sec: %s", format_hex (sec, sec_len, 0, &gc));
+ dmsg (D_SHOW_KEY_SOURCE, "tls1_P_hash seed: %s", format_hex (seed, seed_len, 0, &gc));
+
+ chunk = md_kt_size(md_kt);
+ A1_len = md_kt_size(md_kt);
+
+ hmac_ctx_init(&ctx, sec, sec_len, md_kt);
+ hmac_ctx_init(&ctx_tmp, sec, sec_len, md_kt);
+
+ hmac_ctx_update(&ctx,seed,seed_len);
+ hmac_ctx_final(&ctx, A1);
+
+ n=0;
+ for (;;)
+ {
+ hmac_ctx_reset(&ctx);
+ hmac_ctx_reset(&ctx_tmp);
+ hmac_ctx_update(&ctx,A1,A1_len);
+ hmac_ctx_update(&ctx_tmp,A1,A1_len);
+ hmac_ctx_update(&ctx,seed,seed_len);
+
+ if (olen > chunk)
+ {
+ hmac_ctx_final(&ctx, out);
+ out+=chunk;
+ olen-=chunk;
+ hmac_ctx_final(&ctx_tmp, A1); /* calc the next A1 value */
+ }
+ else /* last one */
+ {
+ hmac_ctx_final(&ctx, A1);
+ memcpy(out,A1,olen);
+ break;
+ }
+ }
+ hmac_ctx_cleanup(&ctx);
+ hmac_ctx_cleanup(&ctx_tmp);
+ CLEAR (A1);
+
+ dmsg (D_SHOW_KEY_SOURCE, "tls1_P_hash out: %s", format_hex (out_orig, olen_orig, 0, &gc));
+ gc_free (&gc);
+}
+
+/*
+ * Use the TLS PRF function for generating data channel keys.
+ * This code is based on the OpenSSL library.
+ *
+ * TLS generates keys as such:
+ *
+ * master_secret[48] = PRF(pre_master_secret[48], "master secret",
+ * ClientHello.random[32] + ServerHello.random[32])
+ *
+ * key_block[] = PRF(SecurityParameters.master_secret[48],
+ * "key expansion",
+ * SecurityParameters.server_random[32] +
+ * SecurityParameters.client_random[32]);
+ *
+ * Notes:
+ *
+ * (1) key_block contains a full set of 4 keys.
+ * (2) The pre-master secret is generated by the client.
+ */
+static void
+tls1_PRF(uint8_t *label,
+ int label_len,
+ const uint8_t *sec,
+ int slen,
+ uint8_t *out1,
+ int olen)
+{
+ struct gc_arena gc = gc_new ();
+ const md_kt_t *md5 = md_kt_get("MD5");
+ const md_kt_t *sha1 = md_kt_get("SHA1");
+ int len,i;
+ const uint8_t *S1,*S2;
+ uint8_t *out2;
+
+ out2 = (uint8_t *) gc_malloc (olen, false, &gc);
+
+ len=slen/2;
+ S1=sec;
+ S2= &(sec[len]);
+ len+=(slen&1); /* add for odd, make longer */
+
+ tls1_P_hash(md5 ,S1,len,label,label_len,out1,olen);
+ tls1_P_hash(sha1,S2,len,label,label_len,out2,olen);
+
+ for (i=0; i<olen; i++)
+ out1[i]^=out2[i];
+
+ memset (out2, 0, olen);
+
+ dmsg (D_SHOW_KEY_SOURCE, "tls1_PRF out[%d]: %s", olen, format_hex (out1, olen, 0, &gc));
+
+ gc_free (&gc);
+}
+
+static void
+openvpn_PRF (const uint8_t *secret,
+ int secret_len,
+ const char *label,
+ const uint8_t *client_seed,
+ int client_seed_len,
+ const uint8_t *server_seed,
+ int server_seed_len,
+ const struct session_id *client_sid,
+ const struct session_id *server_sid,
+ uint8_t *output,
+ int output_len)
+{
+ /* concatenate seed components */
+
+ struct buffer seed = alloc_buf (strlen (label)
+ + client_seed_len
+ + server_seed_len
+ + SID_SIZE * 2);
+
+ ASSERT (buf_write (&seed, label, strlen (label)));
+ ASSERT (buf_write (&seed, client_seed, client_seed_len));
+ ASSERT (buf_write (&seed, server_seed, server_seed_len));
+
+ if (client_sid)
+ ASSERT (buf_write (&seed, client_sid->id, SID_SIZE));
+ if (server_sid)
+ ASSERT (buf_write (&seed, server_sid->id, SID_SIZE));
+
+ /* compute PRF */
+ tls1_PRF (BPTR(&seed), BLEN(&seed), secret, secret_len, output, output_len);
+
+ buf_clear (&seed);
+ free_buf (&seed);
+
+ VALGRIND_MAKE_READABLE ((void *)output, output_len);
+}
+
+/*
+ * Using source entropy from local and remote hosts, mix into
+ * master key.
+ */
+static bool
+generate_key_expansion (struct key_ctx_bi *key,
+ const struct key_type *key_type,
+ const struct key_source2 *key_src,
+ const struct session_id *client_sid,
+ const struct session_id *server_sid,
+ bool server)
+{
+ uint8_t master[48];
+ struct key2 key2;
+ bool ret = false;
+ int i;
+
+ CLEAR (master);
+ CLEAR (key2);
+
+ /* debugging print of source key material */
+ key_source2_print (key_src);
+
+ /* compute master secret */
+ openvpn_PRF (key_src->client.pre_master,
+ sizeof(key_src->client.pre_master),
+ KEY_EXPANSION_ID " master secret",
+ key_src->client.random1,
+ sizeof(key_src->client.random1),
+ key_src->server.random1,
+ sizeof(key_src->server.random1),
+ NULL,
+ NULL,
+ master,
+ sizeof(master));
+
+ /* compute key expansion */
+ openvpn_PRF (master,
+ sizeof(master),
+ KEY_EXPANSION_ID " key expansion",
+ key_src->client.random2,
+ sizeof(key_src->client.random2),
+ key_src->server.random2,
+ sizeof(key_src->server.random2),
+ client_sid,
+ server_sid,
+ (uint8_t*)key2.keys,
+ sizeof(key2.keys));
+
+ key2.n = 2;
+
+ key2_print (&key2, key_type, "Master Encrypt", "Master Decrypt");
+
+ /* check for weak keys */
+ for (i = 0; i < 2; ++i)
+ {
+ fixup_key (&key2.keys[i], key_type);
+ if (!check_key (&key2.keys[i], key_type))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Bad dynamic key generated");
+ goto exit;
+ }
+ }
+
+ /* Initialize OpenSSL key contexts */
+
+ ASSERT (server == true || server == false);
+
+ init_key_ctx (&key->encrypt,
+ &key2.keys[(int)server],
+ key_type,
+ OPENVPN_OP_ENCRYPT,
+ "Data Channel Encrypt");
+
+ init_key_ctx (&key->decrypt,
+ &key2.keys[1-(int)server],
+ key_type,
+ OPENVPN_OP_DECRYPT,
+ "Data Channel Decrypt");
+
+ ret = true;
+
+ exit:
+ CLEAR (master);
+ CLEAR (key2);
+
+ return ret;
+}
+
+static bool
+random_bytes_to_buf (struct buffer *buf,
+ uint8_t *out,
+ int outlen)
+{
+ if (!rand_bytes (out, outlen))
+ msg (M_FATAL, "ERROR: Random number generator cannot obtain entropy for key generation [SSL]");
+ if (!buf_write (buf, out, outlen))
+ return false;
+ return true;
+}
+
+static bool
+key_source2_randomize_write (struct key_source2 *k2,
+ struct buffer *buf,
+ bool server)
+{
+ struct key_source *k = &k2->client;
+ if (server)
+ k = &k2->server;
+
+ CLEAR (*k);
+
+ if (!server)
+ {
+ if (!random_bytes_to_buf (buf, k->pre_master, sizeof (k->pre_master)))
+ return false;
+ }
+
+ if (!random_bytes_to_buf (buf, k->random1, sizeof (k->random1)))
+ return false;
+ if (!random_bytes_to_buf (buf, k->random2, sizeof (k->random2)))
+ return false;
+
+ return true;
+}
+
+static int
+key_source2_read (struct key_source2 *k2,
+ struct buffer *buf,
+ bool server)
+{
+ struct key_source *k = &k2->client;
+
+ if (!server)
+ k = &k2->server;
+
+ CLEAR (*k);
+
+ if (server)
+ {
+ if (!buf_read (buf, k->pre_master, sizeof (k->pre_master)))
+ return 0;
+ }
+
+ if (!buf_read (buf, k->random1, sizeof (k->random1)))
+ return 0;
+ if (!buf_read (buf, k->random2, sizeof (k->random2)))
+ return 0;
+
+ return 1;
+}
+
+static void
+flush_payload_buffer (struct key_state *ks)
+{
+ struct buffer *b;
+
+ while ((b = buffer_list_peek (ks->paybuf)))
+ {
+ key_state_write_plaintext_const (&ks->ks_ssl, b->data, b->len);
+ buffer_list_pop (ks->paybuf);
+ }
+}
+
+/* true if no in/out acknowledgements pending */
+#define FULL_SYNC \
+ (reliable_empty(ks->send_reliable) && reliable_ack_empty (ks->rec_ack))
+
+/*
+ * Move the active key to the lame duck key and reinitialize the
+ * active key.
+ */
+static void
+key_state_soft_reset (struct tls_session *session)
+{
+ struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */
+ struct key_state *ks_lame = &session->key[KS_LAME_DUCK]; /* retiring key */
+
+ ks->must_die = now + session->opt->transition_window; /* remaining lifetime of old key */
+ key_state_free (ks_lame, false);
+ *ks_lame = *ks;
+
+ key_state_init (session, ks);
+ ks->session_id_remote = ks_lame->session_id_remote;
+ ks->remote_addr = ks_lame->remote_addr;
+}
+
+/*
+ * Read/write strings from/to a struct buffer with a u16 length prefix.
+ */
+
+static bool
+write_empty_string (struct buffer *buf)
+{
+ if (!buf_write_u16 (buf, 0))
+ return false;
+ return true;
+}
+
+static bool
+write_string (struct buffer *buf, const char *str, const int maxlen)
+{
+ const int len = strlen (str) + 1;
+ if (len < 1 || (maxlen >= 0 && len > maxlen))
+ return false;
+ if (!buf_write_u16 (buf, len))
+ return false;
+ if (!buf_write (buf, str, len))
+ return false;
+ return true;
+}
+
+static bool
+read_string (struct buffer *buf, char *str, const unsigned int capacity)
+{
+ const int len = buf_read_u16 (buf);
+ if (len < 1 || len > (int)capacity)
+ return false;
+ if (!buf_read (buf, str, len))
+ return false;
+ str[len-1] = '\0';
+ return true;
+}
+
+static char *
+read_string_alloc (struct buffer *buf)
+{
+ const int len = buf_read_u16 (buf);
+ char *str;
+
+ if (len < 1)
+ return NULL;
+ str = (char *) malloc(len);
+ check_malloc_return(str);
+ if (!buf_read (buf, str, len))
+ {
+ free (str);
+ return NULL;
+ }
+ str[len-1] = '\0';
+ return str;
+}
+
+void
+read_string_discard (struct buffer *buf)
+{
+ char *data = read_string_alloc(buf);
+ if (data)
+ free (data);
+}
+
+/*
+ * Handle the reading and writing of key data to and from
+ * the TLS control channel (cleartext).
+ */
+
+static bool
+key_method_1_write (struct buffer *buf, struct tls_session *session)
+{
+ struct key key;
+ struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */
+ struct key_state *ks_lame = &session->key[KS_LAME_DUCK]; /* retiring key */
+
+ ASSERT (session->opt->key_method == 1);
+ ASSERT (buf_init (buf, 0));
+
+ generate_key_random (&key, &session->opt->key_type);
+ if (!check_key (&key, &session->opt->key_type))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Bad encrypting key generated");
+ return false;
+ }
+
+ if (!write_key (&key, &session->opt->key_type, buf))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: write_key failed");
+ return false;
+ }
+
+ init_key_ctx (&ks->key.encrypt, &key, &session->opt->key_type,
+ OPENVPN_OP_ENCRYPT, "Data Channel Encrypt");
+ CLEAR (key);
+
+ /* send local options string */
+ {
+ const char *local_options = local_options_string (session);
+ const int optlen = strlen (local_options) + 1;
+ if (!buf_write (buf, local_options, optlen))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: KM1 write options failed");
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static bool
+push_peer_info(struct buffer *buf, struct tls_session *session)
+{
+ struct gc_arena gc = gc_new ();
+ bool ret = false;
+
+#ifdef ENABLE_PUSH_PEER_INFO
+ if (session->opt->push_peer_info) /* write peer info */
+ {
+ struct env_set *es = session->opt->es;
+ struct env_item *e;
+ struct buffer out = alloc_buf_gc (512*3, &gc);
+
+ /* push version */
+ buf_printf (&out, "IV_VER=%s\n", PACKAGE_VERSION);
+
+ /* push platform */
+#if defined(TARGET_LINUX)
+ buf_printf (&out, "IV_PLAT=linux\n");
+#elif defined(TARGET_SOLARIS)
+ buf_printf (&out, "IV_PLAT=solaris\n");
+#elif defined(TARGET_OPENBSD)
+ buf_printf (&out, "IV_PLAT=openbsd\n");
+#elif defined(TARGET_DARWIN)
+ buf_printf (&out, "IV_PLAT=mac\n");
+#elif defined(TARGET_NETBSD)
+ buf_printf (&out, "IV_PLAT=netbsd\n");
+#elif defined(TARGET_FREEBSD)
+ buf_printf (&out, "IV_PLAT=freebsd\n");
+#elif defined(WIN32)
+ buf_printf (&out, "IV_PLAT=win\n");
+#endif
+
+ /* push mac addr */
+ {
+ struct route_gateway_info rgi;
+ get_default_gateway (&rgi);
+ if (rgi.flags & RGI_HWADDR_DEFINED)
+ buf_printf (&out, "IV_HWADDR=%s\n", format_hex_ex (rgi.hwaddr, 6, 0, 1, ":", &gc));
+ }
+
+ /* push LZO status */
+#ifdef ENABLE_LZO_STUB
+ buf_printf (&out, "IV_LZO_STUB=1\n");
+#endif
+
+ /* push env vars that begin with UV_ */
+ for (e=es->list; e != NULL; e=e->next)
+ {
+ if (e->string)
+ {
+ if (!strncmp(e->string, "UV_", 3) && buf_safe(&out, strlen(e->string)+1))
+ buf_printf (&out, "%s\n", e->string);
+ }
+ }
+
+ if (!write_string(buf, BSTR(&out), -1))
+ goto error;
+ }
+ else
+#endif
+ {
+ if (!write_empty_string (buf)) /* no peer info */
+ goto error;
+ }
+ ret = true;
+
+ error:
+ gc_free (&gc);
+ return ret;
+}
+
+static bool
+key_method_2_write (struct buffer *buf, struct tls_session *session)
+{
+ struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */
+ struct key_state *ks_lame = &session->key[KS_LAME_DUCK]; /* retiring key */
+
+ ASSERT (session->opt->key_method == 2);
+ ASSERT (buf_init (buf, 0));
+
+ /* write a uint32 0 */
+ if (!buf_write_u32 (buf, 0))
+ goto error;
+
+ /* write key_method + flags */
+ if (!buf_write_u8 (buf, (session->opt->key_method & KEY_METHOD_MASK)))
+ goto error;
+
+ /* write key source material */
+ if (!key_source2_randomize_write (ks->key_src, buf, session->opt->server))
+ goto error;
+
+ /* write options string */
+ {
+ if (!write_string (buf, local_options_string (session), TLS_OPTIONS_LEN))
+ goto error;
+ }
+
+ /* write username/password if specified */
+ if (auth_user_pass_enabled)
+ {
+#ifdef ENABLE_CLIENT_CR
+ auth_user_pass_setup (NULL, session->opt->sci);
+#else
+ auth_user_pass_setup (NULL, NULL);
+#endif
+ if (!write_string (buf, auth_user_pass.username, -1))
+ goto error;
+ if (!write_string (buf, auth_user_pass.password, -1))
+ goto error;
+ purge_user_pass (&auth_user_pass, false);
+ }
+ else
+ {
+ if (!write_empty_string (buf)) /* no username */
+ goto error;
+ if (!write_empty_string (buf)) /* no password */
+ goto error;
+ }
+
+ if (!push_peer_info (buf, session))
+ goto error;
+
+ /*
+ * generate tunnel keys if server
+ */
+ if (session->opt->server)
+ {
+ if (ks->authenticated)
+ {
+ if (!generate_key_expansion (&ks->key,
+ &session->opt->key_type,
+ ks->key_src,
+ &ks->session_id_remote,
+ &session->session_id,
+ true))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: server generate_key_expansion failed");
+ goto error;
+ }
+ }
+
+ CLEAR (*ks->key_src);
+ }
+
+ return true;
+
+ error:
+ msg (D_TLS_ERRORS, "TLS Error: Key Method #2 write failed");
+ CLEAR (*ks->key_src);
+ return false;
+}
+
+static bool
+key_method_1_read (struct buffer *buf, struct tls_session *session)
+{
+ int status;
+ struct key key;
+ struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */
+ struct key_state *ks_lame = &session->key[KS_LAME_DUCK]; /* retiring key */
+
+ ASSERT (session->opt->key_method == 1);
+
+ if (!session->verified)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Certificate verification failed (key-method 1)");
+ goto error;
+ }
+
+ status = read_key (&key, &session->opt->key_type, buf);
+ if (status != 1)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Error reading data channel key from plaintext buffer");
+ goto error;
+ }
+
+ if (!check_key (&key, &session->opt->key_type))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Bad decrypting key received from peer");
+ goto error;
+ }
+
+ if (buf->len < 1)
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Missing options string");
+ goto error;
+ }
+
+#ifdef ENABLE_OCC
+ /* compare received remote options string
+ with our locally computed options string */
+ if (!session->opt->disable_occ &&
+ !options_cmp_equal_safe ((char *) BPTR (buf), session->opt->remote_options, buf->len))
+ {
+ options_warning_safe ((char *) BPTR (buf), session->opt->remote_options, buf->len);
+ }
+#endif
+
+ buf_clear (buf);
+
+ init_key_ctx (&ks->key.decrypt, &key, &session->opt->key_type,
+ OPENVPN_OP_DECRYPT, "Data Channel Decrypt");
+ CLEAR (key);
+ ks->authenticated = true;
+ return true;
+
+ error:
+ buf_clear (buf);
+ CLEAR (key);
+ return false;
+}
+
+static bool
+key_method_2_read (struct buffer *buf, struct tls_multi *multi, struct tls_session *session)
+{
+ struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */
+ struct key_state *ks_lame = &session->key[KS_LAME_DUCK]; /* retiring key */
+
+ int key_method_flags;
+ bool username_status, password_status;
+
+ struct gc_arena gc = gc_new ();
+ char *options;
+
+ /* allocate temporary objects */
+ ALLOC_ARRAY_CLEAR_GC (options, char, TLS_OPTIONS_LEN, &gc);
+
+ ASSERT (session->opt->key_method == 2);
+
+ /* discard leading uint32 */
+ ASSERT (buf_advance (buf, 4));
+
+ /* get key method */
+ key_method_flags = buf_read_u8 (buf);
+ if ((key_method_flags & KEY_METHOD_MASK) != 2)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS ERROR: Unknown key_method/flags=%d received from remote host",
+ key_method_flags);
+ goto error;
+ }
+
+ /* get key source material (not actual keys yet) */
+ if (!key_source2_read (ks->key_src, buf, session->opt->server))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Error reading remote data channel key source entropy from plaintext buffer");
+ goto error;
+ }
+
+ /* get options */
+ if (!read_string (buf, options, TLS_OPTIONS_LEN))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Failed to read required OCC options string");
+ goto error;
+ }
+
+ ks->authenticated = false;
+
+ if (verify_user_pass_enabled(session))
+ {
+ /* Perform username/password authentication */
+ struct user_pass *up;
+
+ ALLOC_OBJ_CLEAR_GC (up, struct user_pass, &gc);
+ username_status = read_string (buf, up->username, USER_PASS_LEN);
+ password_status = read_string (buf, up->password, USER_PASS_LEN);
+
+ if (!username_status || !password_status)
+ {
+ CLEAR (*up);
+ if (!(session->opt->ssl_flags & SSLF_AUTH_USER_PASS_OPTIONAL))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Auth Username/Password was not provided by peer");
+ goto error;
+ }
+ }
+
+#ifdef MANAGEMENT_DEF_AUTH
+ /* get peer info from control channel */
+ free (multi->peer_info);
+ multi->peer_info = read_string_alloc (buf);
+#endif
+
+ verify_user_pass(up, multi, session);
+ CLEAR (*up);
+ }
+ else
+ {
+ /* Session verification should have occurred during TLS negotiation*/
+ if (!session->verified)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Certificate verification failed (key-method 2)");
+ goto error;
+ }
+ ks->authenticated = true;
+ }
+
+ /* Perform final authentication checks */
+ if (ks->authenticated)
+ {
+ verify_final_auth_checks(multi, session);
+ }
+
+#ifdef ENABLE_OCC
+ /* check options consistency */
+ if (!session->opt->disable_occ &&
+ !options_cmp_equal (options, session->opt->remote_options))
+ {
+ options_warning (options, session->opt->remote_options);
+ if (session->opt->ssl_flags & SSLF_OPT_VERIFY)
+ {
+ msg (D_TLS_ERRORS, "Option inconsistency warnings triggering disconnect due to --opt-verify");
+ ks->authenticated = false;
+ }
+ }
+#endif
+
+ buf_clear (buf);
+
+ /*
+ * Call OPENVPN_PLUGIN_TLS_FINAL plugin if defined, for final
+ * veto opportunity over authentication decision.
+ */
+ if (ks->authenticated && plugin_defined (session->opt->plugins, OPENVPN_PLUGIN_TLS_FINAL))
+ {
+ if (plugin_call (session->opt->plugins, OPENVPN_PLUGIN_TLS_FINAL, NULL, NULL, session->opt->es) != OPENVPN_PLUGIN_FUNC_SUCCESS)
+ ks->authenticated = false;
+ }
+
+ /*
+ * Generate tunnel keys if client
+ */
+ if (!session->opt->server)
+ {
+ if (!generate_key_expansion (&ks->key,
+ &session->opt->key_type,
+ ks->key_src,
+ &session->session_id,
+ &ks->session_id_remote,
+ false))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: client generate_key_expansion failed");
+ goto error;
+ }
+
+ CLEAR (*ks->key_src);
+ }
+
+ gc_free (&gc);
+ return true;
+
+ error:
+ CLEAR (*ks->key_src);
+ buf_clear (buf);
+ gc_free (&gc);
+ return false;
+}
+
+static int
+auth_deferred_expire_window (const struct tls_options *o)
+{
+ int ret = o->handshake_window;
+ const int r2 = o->renegotiate_seconds / 2;
+
+ if (o->renegotiate_seconds && r2 < ret)
+ ret = r2;
+ return ret;
+}
+
+/*
+ * This is the primary routine for processing TLS stuff inside the
+ * the main event loop. When this routine exits
+ * with non-error status, it will set *wakeup to the number of seconds
+ * when it wants to be called again.
+ *
+ * Return value is true if we have placed a packet in *to_link which we
+ * want to send to our peer.
+ */
+static bool
+tls_process (struct tls_multi *multi,
+ struct tls_session *session,
+ struct buffer *to_link,
+ struct link_socket_actual **to_link_addr,
+ struct link_socket_info *to_link_socket_info,
+ interval_t *wakeup)
+{
+ struct gc_arena gc = gc_new ();
+ struct buffer *buf;
+ bool state_change = false;
+ bool active = false;
+ struct key_state *ks = &session->key[KS_PRIMARY]; /* primary key */
+ struct key_state *ks_lame = &session->key[KS_LAME_DUCK]; /* retiring key */
+
+ /* Make sure we were initialized and that we're not in an error state */
+ ASSERT (ks->state != S_UNDEF);
+ ASSERT (ks->state != S_ERROR);
+ ASSERT (session_id_defined (&session->session_id));
+
+ /* Should we trigger a soft reset? -- new key, keeps old key for a while */
+ if (ks->state >= S_ACTIVE &&
+ ((session->opt->renegotiate_seconds
+ && now >= ks->established + session->opt->renegotiate_seconds)
+ || (session->opt->renegotiate_bytes
+ && ks->n_bytes >= session->opt->renegotiate_bytes)
+ || (session->opt->renegotiate_packets
+ && ks->n_packets >= session->opt->renegotiate_packets)
+ || (packet_id_close_to_wrapping (&ks->packet_id.send))))
+ {
+ msg (D_TLS_DEBUG_LOW,
+ "TLS: soft reset sec=%d bytes=" counter_format "/%d pkts=" counter_format "/%d",
+ (int)(ks->established + session->opt->renegotiate_seconds - now),
+ ks->n_bytes, session->opt->renegotiate_bytes,
+ ks->n_packets, session->opt->renegotiate_packets);
+ key_state_soft_reset (session);
+ }
+
+ /* Kill lame duck key transition_window seconds after primary key negotiation */
+ if (lame_duck_must_die (session, wakeup)) {
+ key_state_free (ks_lame, true);
+ msg (D_TLS_DEBUG_LOW, "TLS: tls_process: killed expiring key");
+ }
+
+ do
+ {
+ update_time ();
+
+ dmsg (D_TLS_DEBUG, "TLS: tls_process: chg=%d ks=%s lame=%s to_link->len=%d wakeup=%d",
+ state_change,
+ state_name (ks->state),
+ state_name (ks_lame->state),
+ to_link->len,
+ *wakeup);
+
+ state_change = false;
+
+ /*
+ * TLS activity is finished once we get to S_ACTIVE,
+ * though we will still process acknowledgements.
+ *
+ * CHANGED with 2.0 -> now we may send tunnel configuration
+ * info over the control channel.
+ */
+ if (true)
+ {
+ /* Initial handshake */
+ if (ks->state == S_INITIAL)
+ {
+ buf = reliable_get_buf_output_sequenced (ks->send_reliable);
+ if (buf)
+ {
+ ks->must_negotiate = now + session->opt->handshake_window;
+ ks->auth_deferred_expire = now + auth_deferred_expire_window (session->opt);
+
+ /* null buffer */
+ reliable_mark_active_outgoing (ks->send_reliable, buf, ks->initial_opcode);
+ INCR_GENERATED;
+
+ ks->state = S_PRE_START;
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "TLS: Initial Handshake, sid=%s",
+ session_id_print (&session->session_id, &gc));
+
+#ifdef ENABLE_MANAGEMENT
+ if (management && ks->initial_opcode != P_CONTROL_SOFT_RESET_V1)
+ {
+ management_set_state (management,
+ OPENVPN_STATE_WAIT,
+ NULL,
+ 0,
+ 0);
+ }
+#endif
+ }
+ }
+
+ /* Are we timed out on receive? */
+ if (now >= ks->must_negotiate)
+ {
+ if (ks->state < S_ACTIVE)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: TLS key negotiation failed to occur within %d seconds (check your network connectivity)",
+ session->opt->handshake_window);
+ goto error;
+ }
+ else /* assume that ks->state == S_ACTIVE */
+ {
+ dmsg (D_TLS_DEBUG_MED, "STATE S_NORMAL_OP");
+ ks->state = S_NORMAL_OP;
+ ks->must_negotiate = 0;
+ }
+ }
+
+ /* Wait for Initial Handshake ACK */
+ if (ks->state == S_PRE_START && FULL_SYNC)
+ {
+ ks->state = S_START;
+ state_change = true;
+ dmsg (D_TLS_DEBUG_MED, "STATE S_START");
+ }
+
+ /* Wait for ACK */
+ if (((ks->state == S_GOT_KEY && !session->opt->server) ||
+ (ks->state == S_SENT_KEY && session->opt->server)))
+ {
+ if (FULL_SYNC)
+ {
+ ks->established = now;
+ dmsg (D_TLS_DEBUG_MED, "STATE S_ACTIVE");
+ if (check_debug_level (D_HANDSHAKE))
+ print_details (&ks->ks_ssl, "Control Channel:");
+ state_change = true;
+ ks->state = S_ACTIVE;
+ INCR_SUCCESS;
+
+ /* Set outgoing address for data channel packets */
+ link_socket_set_outgoing_addr (NULL, to_link_socket_info, &ks->remote_addr, session->common_name, session->opt->es);
+
+ /* Flush any payload packets that were buffered before our state transitioned to S_ACTIVE */
+ flush_payload_buffer (ks);
+
+#ifdef MEASURE_TLS_HANDSHAKE_STATS
+ show_tls_performance_stats();
+#endif
+ }
+ }
+
+ /* Reliable buffer to outgoing TCP/UDP (send up to CONTROL_SEND_ACK_MAX ACKs
+ for previously received packets) */
+ if (!to_link->len && reliable_can_send (ks->send_reliable))
+ {
+ int opcode;
+ struct buffer b;
+
+ buf = reliable_send (ks->send_reliable, &opcode);
+ ASSERT (buf);
+ b = *buf;
+ INCR_SENT;
+
+ write_control_auth (session, ks, &b, to_link_addr, opcode,
+ CONTROL_SEND_ACK_MAX, true);
+ *to_link = b;
+ active = true;
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "Reliable -> TCP/UDP");
+ break;
+ }
+
+#ifndef TLS_AGGREGATE_ACK
+ /* Send 1 or more ACKs (each received control packet gets one ACK) */
+ if (!to_link->len && !reliable_ack_empty (ks->rec_ack))
+ {
+ buf = &ks->ack_write_buf;
+ ASSERT (buf_init (buf, FRAME_HEADROOM (&multi->opt.frame)));
+ write_control_auth (session, ks, buf, to_link_addr, P_ACK_V1,
+ RELIABLE_ACK_SIZE, false);
+ *to_link = *buf;
+ active = true;
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "Dedicated ACK -> TCP/UDP");
+ break;
+ }
+#endif
+
+ /* Write incoming ciphertext to TLS object */
+ buf = reliable_get_buf_sequenced (ks->rec_reliable);
+ if (buf)
+ {
+ int status = 0;
+ if (buf->len)
+ {
+ status = key_state_write_ciphertext (&ks->ks_ssl, buf);
+ if (status == -1)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Incoming Ciphertext -> TLS object write error");
+ goto error;
+ }
+ }
+ else
+ {
+ status = 1;
+ }
+ if (status == 1)
+ {
+ reliable_mark_deleted (ks->rec_reliable, buf, true);
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "Incoming Ciphertext -> TLS");
+ }
+ }
+
+ /* Read incoming plaintext from TLS object */
+ buf = &ks->plaintext_read_buf;
+ if (!buf->len)
+ {
+ int status;
+
+ ASSERT (buf_init (buf, 0));
+ status = key_state_read_plaintext (&ks->ks_ssl, buf, TLS_CHANNEL_BUF_SIZE);
+ update_time ();
+ if (status == -1)
+ {
+ msg (D_TLS_ERRORS, "TLS Error: TLS object -> incoming plaintext read error");
+ goto error;
+ }
+ if (status == 1)
+ {
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "TLS -> Incoming Plaintext");
+ }
+#if 0 /* show null plaintext reads */
+ if (!status)
+ msg (M_INFO, "TLS plaintext read -> NULL return");
+#endif
+ }
+
+ /* Send Key */
+ buf = &ks->plaintext_write_buf;
+ if (!buf->len && ((ks->state == S_START && !session->opt->server) ||
+ (ks->state == S_GOT_KEY && session->opt->server)))
+ {
+ if (session->opt->key_method == 1)
+ {
+ if (!key_method_1_write (buf, session))
+ goto error;
+ }
+ else if (session->opt->key_method == 2)
+ {
+ if (!key_method_2_write (buf, session))
+ goto error;
+ }
+ else
+ {
+ ASSERT (0);
+ }
+
+ state_change = true;
+ dmsg (D_TLS_DEBUG_MED, "STATE S_SENT_KEY");
+ ks->state = S_SENT_KEY;
+ }
+
+ /* Receive Key */
+ buf = &ks->plaintext_read_buf;
+ if (buf->len
+ && ((ks->state == S_SENT_KEY && !session->opt->server)
+ || (ks->state == S_START && session->opt->server)))
+ {
+ if (session->opt->key_method == 1)
+ {
+ if (!key_method_1_read (buf, session))
+ goto error;
+ }
+ else if (session->opt->key_method == 2)
+ {
+ if (!key_method_2_read (buf, multi, session))
+ goto error;
+ }
+ else
+ {
+ ASSERT (0);
+ }
+
+ state_change = true;
+ dmsg (D_TLS_DEBUG_MED, "STATE S_GOT_KEY");
+ ks->state = S_GOT_KEY;
+ }
+
+ /* Write outgoing plaintext to TLS object */
+ buf = &ks->plaintext_write_buf;
+ if (buf->len)
+ {
+ int status = key_state_write_plaintext (&ks->ks_ssl, buf);
+ if (status == -1)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS ERROR: Outgoing Plaintext -> TLS object write error");
+ goto error;
+ }
+ if (status == 1)
+ {
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "Outgoing Plaintext -> TLS");
+ }
+ }
+
+ /* Outgoing Ciphertext to reliable buffer */
+ if (ks->state >= S_START)
+ {
+ buf = reliable_get_buf_output_sequenced (ks->send_reliable);
+ if (buf)
+ {
+ int status = key_state_read_ciphertext (&ks->ks_ssl, buf, PAYLOAD_SIZE_DYNAMIC (&multi->opt.frame));
+ if (status == -1)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Ciphertext -> reliable TCP/UDP transport read error");
+ goto error;
+ }
+ if (status == 1)
+ {
+ reliable_mark_active_outgoing (ks->send_reliable, buf, P_CONTROL_V1);
+ INCR_GENERATED;
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "Outgoing Ciphertext -> Reliable");
+ }
+ }
+ }
+ }
+ }
+ while (state_change);
+
+ update_time ();
+
+#ifdef TLS_AGGREGATE_ACK
+ /* Send 1 or more ACKs (each received control packet gets one ACK) */
+ if (!to_link->len && !reliable_ack_empty (ks->rec_ack))
+ {
+ buf = &ks->ack_write_buf;
+ ASSERT (buf_init (buf, FRAME_HEADROOM (&multi->opt.frame)));
+ write_control_auth (session, ks, buf, to_link_addr, P_ACK_V1,
+ RELIABLE_ACK_SIZE, false);
+ *to_link = *buf;
+ active = true;
+ state_change = true;
+ dmsg (D_TLS_DEBUG, "Dedicated ACK -> TCP/UDP");
+ }
+#endif
+
+ /* When should we wake up again? */
+ {
+ if (ks->state >= S_INITIAL)
+ {
+ compute_earliest_wakeup (wakeup,
+ reliable_send_timeout (ks->send_reliable));
+
+ if (ks->must_negotiate)
+ compute_earliest_wakeup (wakeup, ks->must_negotiate - now);
+ }
+
+ if (ks->established && session->opt->renegotiate_seconds)
+ compute_earliest_wakeup (wakeup,
+ ks->established + session->opt->renegotiate_seconds - now);
+
+ /* prevent event-loop spinning by setting minimum wakeup of 1 second */
+ if (*wakeup <= 0)
+ {
+ *wakeup = 1;
+
+ /* if we had something to send to remote, but to_link was busy,
+ let caller know we need to be called again soon */
+ active = true;
+ }
+
+ dmsg (D_TLS_DEBUG, "TLS: tls_process: timeout set to %d", *wakeup);
+
+ gc_free (&gc);
+ return active;
+ }
+
+error:
+ tls_clear_error();
+ ks->state = S_ERROR;
+ msg (D_TLS_ERRORS, "TLS Error: TLS handshake failed");
+ INCR_ERROR;
+ gc_free (&gc);
+ return false;
+}
+
+/*
+ * Called by the top-level event loop.
+ *
+ * Basically decides if we should call tls_process for
+ * the active or untrusted sessions.
+ */
+
+int
+tls_multi_process (struct tls_multi *multi,
+ struct buffer *to_link,
+ struct link_socket_actual **to_link_addr,
+ struct link_socket_info *to_link_socket_info,
+ interval_t *wakeup)
+{
+ struct gc_arena gc = gc_new ();
+ int i;
+ int active = TLSMP_INACTIVE;
+ bool error = false;
+ int tas;
+
+ perf_push (PERF_TLS_MULTI_PROCESS);
+
+ tls_clear_error ();
+
+ /*
+ * Process each session object having state of S_INITIAL or greater,
+ * and which has a defined remote IP addr.
+ */
+
+ for (i = 0; i < TM_SIZE; ++i)
+ {
+ struct tls_session *session = &multi->session[i];
+ struct key_state *ks = &session->key[KS_PRIMARY];
+ struct key_state *ks_lame = &session->key[KS_LAME_DUCK];
+
+ /* set initial remote address */
+ if (i == TM_ACTIVE && ks->state == S_INITIAL &&
+ link_socket_actual_defined (&to_link_socket_info->lsa->actual))
+ ks->remote_addr = to_link_socket_info->lsa->actual;
+
+ dmsg (D_TLS_DEBUG,
+ "TLS: tls_multi_process: i=%d state=%s, mysid=%s, stored-sid=%s, stored-ip=%s",
+ i,
+ state_name (ks->state),
+ session_id_print (&session->session_id, &gc),
+ session_id_print (&ks->session_id_remote, &gc),
+ print_link_socket_actual (&ks->remote_addr, &gc));
+
+ if (ks->state >= S_INITIAL && link_socket_actual_defined (&ks->remote_addr))
+ {
+ struct link_socket_actual *tla = NULL;
+
+ update_time ();
+
+ if (tls_process (multi, session, to_link, &tla,
+ to_link_socket_info, wakeup))
+ active = TLSMP_ACTIVE;
+
+ /*
+ * If tls_process produced an outgoing packet,
+ * return the link_socket_actual object (which
+ * contains the outgoing address).
+ */
+ if (tla)
+ {
+ multi->to_link_addr = *tla;
+ *to_link_addr = &multi->to_link_addr;
+ }
+
+ /*
+ * If tls_process hits an error:
+ * (1) If the session has an unexpired lame duck key, preserve it.
+ * (2) Reinitialize the session.
+ * (3) Increment soft error count
+ */
+ if (ks->state == S_ERROR)
+ {
+ ++multi->n_soft_errors;
+
+ if (i == TM_ACTIVE)
+ error = true;
+
+ if (i == TM_ACTIVE
+ && ks_lame->state >= S_ACTIVE
+ && !multi->opt.single_session)
+ move_session (multi, TM_LAME_DUCK, TM_ACTIVE, true);
+ else
+ reset_session (multi, session);
+ }
+ }
+ }
+
+ update_time ();
+
+ tas = tls_authentication_status (multi, TLS_MULTI_AUTH_STATUS_INTERVAL);
+
+ /*
+ * If lame duck session expires, kill it.
+ */
+ if (lame_duck_must_die (&multi->session[TM_LAME_DUCK], wakeup)) {
+ tls_session_free (&multi->session[TM_LAME_DUCK], true);
+ msg (D_TLS_DEBUG_LOW, "TLS: tls_multi_process: killed expiring key");
+ }
+
+ /*
+ * If untrusted session achieves TLS authentication,
+ * move it to active session, usurping any prior session.
+ *
+ * A semi-trusted session is one in which the certificate authentication
+ * succeeded (if cert verification is enabled) but the username/password
+ * verification failed. A semi-trusted session can forward data on the
+ * TLS control channel but not on the tunnel channel.
+ */
+ if (DECRYPT_KEY_ENABLED (multi, &multi->session[TM_UNTRUSTED].key[KS_PRIMARY])) {
+ move_session (multi, TM_ACTIVE, TM_UNTRUSTED, true);
+ msg (D_TLS_DEBUG_LOW, "TLS: tls_multi_process: untrusted session promoted to %strusted",
+ tas == TLS_AUTHENTICATION_SUCCEEDED ? "" : "semi-");
+ }
+
+ /*
+ * A hard error means that TM_ACTIVE hit an S_ERROR state and that no
+ * other key state objects are S_ACTIVE or higher.
+ */
+ if (error)
+ {
+ for (i = 0; i < (int) SIZE (multi->key_scan); ++i)
+ {
+ if (multi->key_scan[i]->state >= S_ACTIVE)
+ goto nohard;
+ }
+ ++multi->n_hard_errors;
+ }
+ nohard:
+
+#ifdef ENABLE_DEBUG
+ /* DEBUGGING -- flood peer with repeating connection attempts */
+ {
+ const int throw_level = GREMLIN_CONNECTION_FLOOD_LEVEL (multi->opt.gremlin);
+ if (throw_level)
+ {
+ for (i = 0; i < (int) SIZE (multi->key_scan); ++i)
+ {
+ if (multi->key_scan[i]->state >= throw_level)
+ {
+ ++multi->n_hard_errors;
+ ++multi->n_soft_errors;
+ }
+ }
+ }
+ }
+#endif
+
+ perf_pop ();
+ gc_free (&gc);
+
+ return (tas == TLS_AUTHENTICATION_FAILED) ? TLSMP_KILL : active;
+}
+
+/*
+ * Pre and post-process the encryption & decryption buffers in order
+ * to implement a multiplexed TLS channel over the TCP/UDP port.
+ */
+
+/*
+ *
+ * When we are in TLS mode, this is the first routine which sees
+ * an incoming packet.
+ *
+ * If it's a data packet, we set opt so that our caller can
+ * decrypt it. We also give our caller the appropriate decryption key.
+ *
+ * If it's a control packet, we authenticate it and process it,
+ * possibly creating a new tls_session if it represents the
+ * first packet of a new session. For control packets, we will
+ * also zero the size of *buf so that our caller ignores the
+ * packet on our return.
+ *
+ * Note that openvpn only allows one active session at a time,
+ * so a new session (once authenticated) will always usurp
+ * an old session.
+ *
+ * Return true if input was an authenticated control channel
+ * packet.
+ *
+ * If we are running in TLS thread mode, all public routines
+ * below this point must be called with the L_TLS lock held.
+ */
+
+bool
+tls_pre_decrypt (struct tls_multi *multi,
+ const struct link_socket_actual *from,
+ struct buffer *buf,
+ struct crypto_options *opt)
+{
+ struct gc_arena gc = gc_new ();
+ bool ret = false;
+
+ if (buf->len > 0)
+ {
+ int i;
+ int op;
+ int key_id;
+
+ /* get opcode and key ID */
+ {
+ uint8_t c = *BPTR (buf);
+ op = c >> P_OPCODE_SHIFT;
+ key_id = c & P_KEY_ID_MASK;
+ }
+
+ if (op == P_DATA_V1)
+ { /* data channel packet */
+ for (i = 0; i < KEY_SCAN_SIZE; ++i)
+ {
+ struct key_state *ks = multi->key_scan[i];
+
+ /*
+ * This is the basic test of TLS state compatibility between a local OpenVPN
+ * instance and its remote peer.
+ *
+ * If the test fails, it tells us that we are getting a packet from a source
+ * which claims reference to a prior negotiated TLS session, but the local
+ * OpenVPN instance has no memory of such a negotiation.
+ *
+ * It almost always occurs on UDP sessions when the passive side of the
+ * connection is restarted without the active side restarting as well (the
+ * passive side is the server which only listens for the connections, the
+ * active side is the client which initiates connections).
+ */
+ if (DECRYPT_KEY_ENABLED (multi, ks)
+ && key_id == ks->key_id
+ && ks->authenticated
+#ifdef ENABLE_DEF_AUTH
+ && !ks->auth_deferred
+#endif
+ && link_socket_actual_match (from, &ks->remote_addr))
+ {
+ /* return appropriate data channel decrypt key in opt */
+ opt->key_ctx_bi = &ks->key;
+ opt->packet_id = multi->opt.replay ? &ks->packet_id : NULL;
+ opt->pid_persist = NULL;
+ opt->flags &= multi->opt.crypto_flags_and;
+ opt->flags |= multi->opt.crypto_flags_or;
+ ASSERT (buf_advance (buf, 1));
+ ++ks->n_packets;
+ ks->n_bytes += buf->len;
+ dmsg (D_TLS_KEYSELECT,
+ "TLS: tls_pre_decrypt, key_id=%d, IP=%s",
+ key_id, print_link_socket_actual (from, &gc));
+ gc_free (&gc);
+ return ret;
+ }
+#if 0 /* keys out of sync? */
+ else
+ {
+ dmsg (D_TLS_ERRORS, "TLS_PRE_DECRYPT: [%d] dken=%d rkid=%d lkid=%d auth=%d def=%d match=%d",
+ i,
+ DECRYPT_KEY_ENABLED (multi, ks),
+ key_id,
+ ks->key_id,
+ ks->authenticated,
+#ifdef ENABLE_DEF_AUTH
+ ks->auth_deferred,
+#else
+ -1,
+#endif
+ link_socket_actual_match (from, &ks->remote_addr));
+ }
+#endif
+ }
+
+ msg (D_TLS_ERRORS,
+ "TLS Error: local/remote TLS keys are out of sync: %s [%d]",
+ print_link_socket_actual (from, &gc), key_id);
+ goto error_lite;
+ }
+ else /* control channel packet */
+ {
+ bool do_burst = false;
+ bool new_link = false;
+ struct session_id sid; /* remote session ID */
+
+ /* verify legal opcode */
+ if (op < P_FIRST_OPCODE || op > P_LAST_OPCODE)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: unknown opcode received from %s op=%d",
+ print_link_socket_actual (from, &gc), op);
+ goto error;
+ }
+
+ /* hard reset ? */
+ if (is_hard_reset (op, 0))
+ {
+ /* verify client -> server or server -> client connection */
+ if (((op == P_CONTROL_HARD_RESET_CLIENT_V1
+ || op == P_CONTROL_HARD_RESET_CLIENT_V2) && !multi->opt.server)
+ || ((op == P_CONTROL_HARD_RESET_SERVER_V1
+ || op == P_CONTROL_HARD_RESET_SERVER_V2) && multi->opt.server))
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: client->client or server->server connection attempted from %s",
+ print_link_socket_actual (from, &gc));
+ goto error;
+ }
+ }
+
+ /*
+ * Authenticate Packet
+ */
+ dmsg (D_TLS_DEBUG, "TLS: control channel, op=%s, IP=%s",
+ packet_opcode_name (op), print_link_socket_actual (from, &gc));
+
+ /* get remote session-id */
+ {
+ struct buffer tmp = *buf;
+ buf_advance (&tmp, 1);
+ if (!session_id_read (&sid, &tmp) || !session_id_defined (&sid))
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: session-id not found in packet from %s",
+ print_link_socket_actual (from, &gc));
+ goto error;
+ }
+ }
+
+ /* use session ID to match up packet with appropriate tls_session object */
+ for (i = 0; i < TM_SIZE; ++i)
+ {
+ struct tls_session *session = &multi->session[i];
+ struct key_state *ks = &session->key[KS_PRIMARY];
+
+ dmsg (D_TLS_DEBUG,
+ "TLS: initial packet test, i=%d state=%s, mysid=%s, rec-sid=%s, rec-ip=%s, stored-sid=%s, stored-ip=%s",
+ i,
+ state_name (ks->state),
+ session_id_print (&session->session_id, &gc),
+ session_id_print (&sid, &gc),
+ print_link_socket_actual (from, &gc),
+ session_id_print (&ks->session_id_remote, &gc),
+ print_link_socket_actual (&ks->remote_addr, &gc));
+
+ if (session_id_equal (&ks->session_id_remote, &sid))
+ /* found a match */
+ {
+ if (i == TM_LAME_DUCK) {
+ msg (D_TLS_ERRORS,
+ "TLS ERROR: received control packet with stale session-id=%s",
+ session_id_print (&sid, &gc));
+ goto error;
+ }
+ dmsg (D_TLS_DEBUG,
+ "TLS: found match, session[%d], sid=%s",
+ i, session_id_print (&sid, &gc));
+ break;
+ }
+ }
+
+ /*
+ * Initial packet received.
+ */
+
+ if (i == TM_SIZE && is_hard_reset (op, 0))
+ {
+ struct tls_session *session = &multi->session[TM_ACTIVE];
+ struct key_state *ks = &session->key[KS_PRIMARY];
+
+ if (!is_hard_reset (op, multi->opt.key_method))
+ {
+ msg (D_TLS_ERRORS, "TLS ERROR: initial packet local/remote key_method mismatch, local key_method=%d, op=%s",
+ multi->opt.key_method,
+ packet_opcode_name (op));
+ goto error;
+ }
+
+ /*
+ * If we have no session currently in progress, the initial packet will
+ * open a new session in TM_ACTIVE rather than TM_UNTRUSTED.
+ */
+ if (!session_id_defined (&ks->session_id_remote))
+ {
+ if (multi->opt.single_session && multi->n_sessions)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Cannot accept new session request from %s due to session context expire or --single-session [1]",
+ print_link_socket_actual (from, &gc));
+ goto error;
+ }
+
+#ifdef ENABLE_MANAGEMENT
+ if (management)
+ {
+ management_set_state (management,
+ OPENVPN_STATE_AUTH,
+ NULL,
+ 0,
+ 0);
+ }
+#endif
+
+ msg (D_TLS_DEBUG_LOW,
+ "TLS: Initial packet from %s, sid=%s",
+ print_link_socket_actual (from, &gc),
+ session_id_print (&sid, &gc));
+
+ do_burst = true;
+ new_link = true;
+ i = TM_ACTIVE;
+ session->untrusted_addr = *from;
+ }
+ }
+
+ if (i == TM_SIZE && is_hard_reset (op, 0))
+ {
+ /*
+ * No match with existing sessions,
+ * probably a new session.
+ */
+ struct tls_session *session = &multi->session[TM_UNTRUSTED];
+
+ /*
+ * If --single-session, don't allow any hard-reset connection request
+ * unless it the the first packet of the session.
+ */
+ if (multi->opt.single_session)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Cannot accept new session request from %s due to session context expire or --single-session [2]",
+ print_link_socket_actual (from, &gc));
+ goto error;
+ }
+
+ if (!is_hard_reset (op, multi->opt.key_method))
+ {
+ msg (D_TLS_ERRORS, "TLS ERROR: new session local/remote key_method mismatch, local key_method=%d, op=%s",
+ multi->opt.key_method,
+ packet_opcode_name (op));
+ goto error;
+ }
+
+ if (!read_control_auth (buf, &session->tls_auth, from))
+ goto error;
+
+ /*
+ * New session-initiating control packet is authenticated at this point,
+ * assuming that the --tls-auth command line option was used.
+ *
+ * Without --tls-auth, we leave authentication entirely up to TLS.
+ */
+ msg (D_TLS_DEBUG_LOW,
+ "TLS: new session incoming connection from %s",
+ print_link_socket_actual (from, &gc));
+
+ new_link = true;
+ i = TM_UNTRUSTED;
+ session->untrusted_addr = *from;
+ }
+ else
+ {
+ struct tls_session *session = &multi->session[i];
+ struct key_state *ks = &session->key[KS_PRIMARY];
+
+ /*
+ * Packet must belong to an existing session.
+ */
+ if (i != TM_ACTIVE && i != TM_UNTRUSTED)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Unroutable control packet received from %s (si=%d op=%s)",
+ print_link_socket_actual (from, &gc),
+ i,
+ packet_opcode_name (op));
+ goto error;
+ }
+
+ /*
+ * Verify remote IP address
+ */
+ if (!new_link && !link_socket_actual_match (&ks->remote_addr, from))
+ {
+ msg (D_TLS_ERRORS, "TLS Error: Received control packet from unexpected IP addr: %s",
+ print_link_socket_actual (from, &gc));
+ goto error;
+ }
+
+ /*
+ * Remote is requesting a key renegotiation
+ */
+ if (op == P_CONTROL_SOFT_RESET_V1
+ && DECRYPT_KEY_ENABLED (multi, ks))
+ {
+ if (!read_control_auth (buf, &session->tls_auth, from))
+ goto error;
+
+ key_state_soft_reset (session);
+
+ dmsg (D_TLS_DEBUG,
+ "TLS: received P_CONTROL_SOFT_RESET_V1 s=%d sid=%s",
+ i, session_id_print (&sid, &gc));
+ }
+ else
+ {
+ /*
+ * Remote responding to our key renegotiation request?
+ */
+ if (op == P_CONTROL_SOFT_RESET_V1)
+ do_burst = true;
+
+ if (!read_control_auth (buf, &session->tls_auth, from))
+ goto error;
+
+ dmsg (D_TLS_DEBUG,
+ "TLS: received control channel packet s#=%d sid=%s",
+ i, session_id_print (&sid, &gc));
+ }
+ }
+
+ /*
+ * We have an authenticated packet (if --tls-auth was set).
+ * Now pass to our reliability level which deals with
+ * packet acknowledgements, retransmits, sequencing, etc.
+ */
+ {
+ struct tls_session *session = &multi->session[i];
+ struct key_state *ks = &session->key[KS_PRIMARY];
+
+ /* Make sure we were initialized and that we're not in an error state */
+ ASSERT (ks->state != S_UNDEF);
+ ASSERT (ks->state != S_ERROR);
+ ASSERT (session_id_defined (&session->session_id));
+
+ /* Let our caller know we processed a control channel packet */
+ ret = true;
+
+ /*
+ * Set our remote address and remote session_id
+ */
+ if (new_link)
+ {
+ ks->session_id_remote = sid;
+ ks->remote_addr = *from;
+ ++multi->n_sessions;
+ }
+ else if (!link_socket_actual_match (&ks->remote_addr, from))
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: Existing session control channel packet from unknown IP address: %s",
+ print_link_socket_actual (from, &gc));
+ goto error;
+ }
+
+ /*
+ * Should we do a retransmit of all unacknowledged packets in
+ * the send buffer? This improves the start-up efficiency of the
+ * initial key negotiation after the 2nd peer comes online.
+ */
+ if (do_burst && !session->burst)
+ {
+ reliable_schedule_now (ks->send_reliable);
+ session->burst = true;
+ }
+
+ /* Check key_id */
+ if (ks->key_id != key_id)
+ {
+ msg (D_TLS_ERRORS,
+ "TLS ERROR: local/remote key IDs out of sync (%d/%d) ID: %s",
+ ks->key_id, key_id, print_key_id (multi, &gc));
+ goto error;
+ }
+
+ /*
+ * Process incoming ACKs for packets we can now
+ * delete from reliable send buffer
+ */
+ {
+ /* buffers all packet IDs to delete from send_reliable */
+ struct reliable_ack send_ack;
+
+ send_ack.len = 0;
+ if (!reliable_ack_read (&send_ack, buf, &session->session_id))
+ {
+ msg (D_TLS_ERRORS,
+ "TLS Error: reading acknowledgement record from packet");
+ goto error;
+ }
+ reliable_send_purge (ks->send_reliable, &send_ack);
+ }
+
+ if (op != P_ACK_V1 && reliable_can_get (ks->rec_reliable))
+ {
+ packet_id_type id;
+
+ /* Extract the packet ID from the packet */
+ if (reliable_ack_read_packet_id (buf, &id))
+ {
+ /* Avoid deadlock by rejecting packet that would de-sequentialize receive buffer */
+ if (reliable_wont_break_sequentiality (ks->rec_reliable, id))
+ {
+ if (reliable_not_replay (ks->rec_reliable, id))
+ {
+ /* Save incoming ciphertext packet to reliable buffer */
+ struct buffer *in = reliable_get_buf (ks->rec_reliable);
+ ASSERT (in);
+ ASSERT (buf_copy (in, buf));
+ reliable_mark_active_incoming (ks->rec_reliable, in, id, op);
+ }
+
+ /* Process outgoing acknowledgment for packet just received, even if it's a replay */
+ reliable_ack_acknowledge_packet_id (ks->rec_ack, id);
+ }
+ }
+ }
+ }
+ }
+ }
+
+ done:
+ buf->len = 0;
+ opt->key_ctx_bi = NULL;
+ opt->packet_id = NULL;
+ opt->pid_persist = NULL;
+ opt->flags &= multi->opt.crypto_flags_and;
+ gc_free (&gc);
+ return ret;
+
+ error:
+ ++multi->n_soft_errors;
+ error_lite:
+ tls_clear_error();
+ goto done;
+}
+
+/*
+ * This function is similar to tls_pre_decrypt, except it is called
+ * when we are in server mode and receive an initial incoming
+ * packet. Note that we don't modify
+ * any state in our parameter objects. The purpose is solely to
+ * determine whether we should generate a client instance
+ * object, in which case true is returned.
+ *
+ * This function is essentially the first-line HMAC firewall
+ * on the UDP port listener in --mode server mode.
+ */
+bool
+tls_pre_decrypt_lite (const struct tls_auth_standalone *tas,
+ const struct link_socket_actual *from,
+ const struct buffer *buf)
+
+{
+ struct gc_arena gc = gc_new ();
+ bool ret = false;
+
+ if (buf->len > 0)
+ {
+ int op;
+ int key_id;
+
+ /* get opcode and key ID */
+ {
+ uint8_t c = *BPTR (buf);
+ op = c >> P_OPCODE_SHIFT;
+ key_id = c & P_KEY_ID_MASK;
+ }
+
+ /* this packet is from an as-yet untrusted source, so
+ scrutinize carefully */
+
+ if (op != P_CONTROL_HARD_RESET_CLIENT_V2)
+ {
+ /*
+ * This can occur due to bogus data or DoS packets.
+ */
+ dmsg (D_TLS_STATE_ERRORS,
+ "TLS State Error: No TLS state for client %s, opcode=%d",
+ print_link_socket_actual (from, &gc),
+ op);
+ goto error;
+ }
+
+ if (key_id != 0)
+ {
+ dmsg (D_TLS_STATE_ERRORS,
+ "TLS State Error: Unknown key ID (%d) received from %s -- 0 was expected",
+ key_id,
+ print_link_socket_actual (from, &gc));
+ goto error;
+ }
+
+ if (buf->len > EXPANDED_SIZE_DYNAMIC (&tas->frame))
+ {
+ dmsg (D_TLS_STATE_ERRORS,
+ "TLS State Error: Large packet (size %d) received from %s -- a packet no larger than %d bytes was expected",
+ buf->len,
+ print_link_socket_actual (from, &gc),
+ EXPANDED_SIZE_DYNAMIC (&tas->frame));
+ goto error;
+ }
+
+ {
+ struct buffer newbuf = clone_buf (buf);
+ struct crypto_options co = tas->tls_auth_options;
+ bool status;
+
+ /*
+ * We are in read-only mode at this point with respect to TLS
+ * control channel state. After we build a new client instance
+ * object, we will process this session-initiating packet for real.
+ */
+ co.flags |= CO_IGNORE_PACKET_ID;
+
+ /* HMAC test, if --tls-auth was specified */
+ status = read_control_auth (&newbuf, &co, from);
+ free_buf (&newbuf);
+ if (!status)
+ goto error;
+
+ /*
+ * At this point, if --tls-auth is being used, we know that
+ * the packet has passed the HMAC test, but we don't know if
+ * it is a replay yet. We will attempt to defeat replays
+ * by not advancing to the S_START state until we
+ * receive an ACK from our first reply to the client
+ * that includes an HMAC of our randomly generated 64 bit
+ * session ID.
+ *
+ * On the other hand if --tls-auth is not being used, we
+ * will proceed to begin the TLS authentication
+ * handshake with only cursory integrity checks having
+ * been performed, since we will be leaving the task
+ * of authentication solely up to TLS.
+ */
+
+ ret = true;
+ }
+ }
+ gc_free (&gc);
+ return ret;
+
+ error:
+ tls_clear_error();
+ gc_free (&gc);
+ return ret;
+}
+
+/* Choose the key with which to encrypt a data packet */
+void
+tls_pre_encrypt (struct tls_multi *multi,
+ struct buffer *buf, struct crypto_options *opt)
+{
+ multi->save_ks = NULL;
+ if (buf->len > 0)
+ {
+ int i;
+ struct key_state *ks_select = NULL;
+ for (i = 0; i < KEY_SCAN_SIZE; ++i)
+ {
+ struct key_state *ks = multi->key_scan[i];
+ if (ks->state >= S_ACTIVE
+ && ks->authenticated
+#ifdef ENABLE_DEF_AUTH
+ && !ks->auth_deferred
+#endif
+ )
+ {
+ if (!ks_select)
+ ks_select = ks;
+ if (now >= ks->auth_deferred_expire)
+ {
+ ks_select = ks;
+ break;
+ }
+ }
+ }
+
+ if (ks_select)
+ {
+ opt->key_ctx_bi = &ks_select->key;
+ opt->packet_id = multi->opt.replay ? &ks_select->packet_id : NULL;
+ opt->pid_persist = NULL;
+ opt->flags &= multi->opt.crypto_flags_and;
+ opt->flags |= multi->opt.crypto_flags_or;
+ multi->save_ks = ks_select;
+ dmsg (D_TLS_KEYSELECT, "TLS: tls_pre_encrypt: key_id=%d", ks_select->key_id);
+ return;
+ }
+ else
+ {
+ struct gc_arena gc = gc_new ();
+ dmsg (D_TLS_KEYSELECT, "TLS Warning: no data channel send key available: %s",
+ print_key_id (multi, &gc));
+ gc_free (&gc);
+ }
+ }
+
+ buf->len = 0;
+ opt->key_ctx_bi = NULL;
+ opt->packet_id = NULL;
+ opt->pid_persist = NULL;
+ opt->flags &= multi->opt.crypto_flags_and;
+}
+
+/* Prepend the appropriate opcode to encrypted buffer prior to TCP/UDP send */
+void
+tls_post_encrypt (struct tls_multi *multi, struct buffer *buf)
+{
+ struct key_state *ks;
+ uint8_t *op;
+
+ ks = multi->save_ks;
+ multi->save_ks = NULL;
+ if (buf->len > 0)
+ {
+ ASSERT (ks);
+ ASSERT (op = buf_prepend (buf, 1));
+ *op = (P_DATA_V1 << P_OPCODE_SHIFT) | ks->key_id;
+ ++ks->n_packets;
+ ks->n_bytes += buf->len;
+ }
+}
+
+/*
+ * Send a payload over the TLS control channel.
+ * Called externally.
+ */
+
+bool
+tls_send_payload (struct tls_multi *multi,
+ const uint8_t *data,
+ int size)
+{
+ struct tls_session *session;
+ struct key_state *ks;
+ bool ret = false;
+
+ tls_clear_error();
+
+ ASSERT (multi);
+
+ session = &multi->session[TM_ACTIVE];
+ ks = &session->key[KS_PRIMARY];
+
+ if (ks->state >= S_ACTIVE)
+ {
+ if (key_state_write_plaintext_const (&ks->ks_ssl, data, size) == 1)
+ ret = true;
+ }
+ else
+ {
+ if (!ks->paybuf)
+ ks->paybuf = buffer_list_new (0);
+ buffer_list_push_data (ks->paybuf, data, (size_t)size);
+ ret = true;
+ }
+
+
+ tls_clear_error();
+
+ return ret;
+}
+
+bool
+tls_rec_payload (struct tls_multi *multi,
+ struct buffer *buf)
+{
+ struct tls_session *session;
+ struct key_state *ks;
+ bool ret = false;
+
+ tls_clear_error();
+
+ ASSERT (multi);
+
+ session = &multi->session[TM_ACTIVE];
+ ks = &session->key[KS_PRIMARY];
+
+ if (ks->state >= S_ACTIVE && BLEN (&ks->plaintext_read_buf))
+ {
+ if (buf_copy (buf, &ks->plaintext_read_buf))
+ ret = true;
+ ks->plaintext_read_buf.len = 0;
+ }
+
+ tls_clear_error();
+
+ return ret;
+}
+
+/*
+ * Dump a human-readable rendition of an openvpn packet
+ * into a garbage collectable string which is returned.
+ */
+const char *
+protocol_dump (struct buffer *buffer, unsigned int flags, struct gc_arena *gc)
+{
+ struct buffer out = alloc_buf_gc (256, gc);
+ struct buffer buf = *buffer;
+
+ uint8_t c;
+ int op;
+ int key_id;
+
+ int tls_auth_hmac_size = (flags & PD_TLS_AUTH_HMAC_SIZE_MASK);
+
+ if (buf.len <= 0)
+ {
+ buf_printf (&out, "DATA UNDEF len=%d", buf.len);
+ goto done;
+ }
+
+ if (!(flags & PD_TLS))
+ goto print_data;
+
+ /*
+ * Initial byte (opcode)
+ */
+ if (!buf_read (&buf, &c, sizeof (c)))
+ goto done;
+ op = (c >> P_OPCODE_SHIFT);
+ key_id = c & P_KEY_ID_MASK;
+ buf_printf (&out, "%s kid=%d", packet_opcode_name (op), key_id);
+
+ if (op == P_DATA_V1)
+ goto print_data;
+
+ /*
+ * Session ID
+ */
+ {
+ struct session_id sid;
+
+ if (!session_id_read (&sid, &buf))
+ goto done;
+ if (flags & PD_VERBOSE)
+ buf_printf (&out, " sid=%s", session_id_print (&sid, gc));
+ }
+
+ /*
+ * tls-auth hmac + packet_id
+ */
+ if (tls_auth_hmac_size)
+ {
+ struct packet_id_net pin;
+ uint8_t tls_auth_hmac[MAX_HMAC_KEY_LENGTH];
+
+ ASSERT (tls_auth_hmac_size <= MAX_HMAC_KEY_LENGTH);
+
+ if (!buf_read (&buf, tls_auth_hmac, tls_auth_hmac_size))
+ goto done;
+ if (flags & PD_VERBOSE)
+ buf_printf (&out, " tls_hmac=%s", format_hex (tls_auth_hmac, tls_auth_hmac_size, 0, gc));
+
+ if (!packet_id_read (&pin, &buf, true))
+ goto done;
+ buf_printf(&out, " pid=%s", packet_id_net_print (&pin, (flags & PD_VERBOSE), gc));
+ }
+
+ /*
+ * ACK list
+ */
+ buf_printf (&out, " %s", reliable_ack_print(&buf, (flags & PD_VERBOSE), gc));
+
+ if (op == P_ACK_V1)
+ goto done;
+
+ /*
+ * Packet ID
+ */
+ {
+ packet_id_type l;
+ if (!buf_read (&buf, &l, sizeof (l)))
+ goto done;
+ l = ntohpid (l);
+ buf_printf (&out, " pid=" packet_id_format, (packet_id_print_type)l);
+ }
+
+print_data:
+ if (flags & PD_SHOW_DATA)
+ buf_printf (&out, " DATA %s", format_hex (BPTR (&buf), BLEN (&buf), 80, gc));
+ else
+ buf_printf (&out, " DATA len=%d", buf.len);
+
+done:
+ return BSTR (&out);
+}
+
+#else
+static void dummy(void) {}
+#endif /* ENABLE_CRYPTO && ENABLE_SSL*/