struct multi_instance *
multi_get_create_instance_udp (struct multi_context *m)
{
struct gc_arena gc = gc_new ();
struct mroute_addr real;
struct multi_instance *mi = NULL;
struct hash *hash = m->hash;
if (mroute_extract_openvpn_sockaddr (&real, &m->top.c2.from.dest, true))
{
struct hash_element *he;
const uint32_t hv = hash_value (hash, &real);
struct hash_bucket *bucket = hash_bucket (hash, hv);
uint8_t* ptr = BPTR(&m->top.c2.buf);
uint8_t op = ptr[0] >> P_OPCODE_SHIFT;
uint32_t sess_id;
bool session_forged = false;
if (op == P_DATA_V2)
{
sess_id = (*(uint32_t*)ptr) >> 8;
if ((sess_id < m->max_clients) && (m->instances[sess_id]))
{
mi = m->instances[sess_id];
if (!link_socket_actual_match(&mi->context.c2.from, &m->top.c2.from))
{
msg(D_MULTI_MEDIUM, "floating detected from %s to %s",
print_link_socket_actual (&mi->context.c2.from, &gc), print_link_socket_actual (&m->top.c2.from, &gc));
/* session-id is not trusted, so check hmac */
session_forged = !(crypto_test_hmac(&m->top.c2.buf, &mi->context.c2.crypto_options));
if (session_forged)
{
mi = NULL;
msg (D_MULTI_MEDIUM, "hmac verification failed, session forge detected!");
}
else
{
update_floated(m, mi, real, hv);
}
}
}
}
else
{
void
process_incoming_link (struct context *c)
{
struct gc_arena gc = gc_new ();
bool decrypt_status;
struct link_socket_info *lsi = get_link_socket_info (c);
const uint8_t *orig_buf = c->c2.buf.data;
perf_push (PERF_PROC_IN_LINK);
if (c->c2.buf.len > 0)
{
c->c2.link_read_bytes += c->c2.buf.len;
link_read_bytes_global += c->c2.buf.len;
#ifdef ENABLE_MEMSTATS
if (mmap_stats)
mmap_stats->link_read_bytes = link_read_bytes_global;
#endif
c->c2.original_recv_size = c->c2.buf.len;
#ifdef ENABLE_MANAGEMENT
if (management)
{
management_bytes_in (management, c->c2.buf.len);
#ifdef MANAGEMENT_DEF_AUTH
management_bytes_server (management, &c->c2.link_read_bytes, &c->c2.link_write_bytes, &c->c2.mda_context);
#endif
}
#endif
}
else
c->c2.original_recv_size = 0;
#ifdef ENABLE_DEBUG
/* take action to corrupt packet if we are in gremlin test mode */
if (c->options.gremlin) {
if (!ask_gremlin (c->options.gremlin))
c->c2.buf.len = 0;
corrupt_gremlin (&c->c2.buf, c->options.gremlin);
}
#endif
/* log incoming packet */
#ifdef LOG_RW
if (c->c2.log_rw && c->c2.buf.len > 0)
fprintf (stderr, "R");
#endif
msg (D_LINK_RW, "%s READ [%d] from %s: %s",
proto2ascii (lsi->proto, true),
BLEN (&c->c2.buf),
print_link_socket_actual (&c->c2.from, &gc),
PROTO_DUMP (&c->c2.buf, &gc));
/*
* Good, non-zero length packet received.
* Commence multi-stage processing of packet,
* such as authenticate, decrypt, decompress.
* If any stage fails, it sets buf.len to 0 or -1,
* telling downstream stages to ignore the packet.
*/
if (c->c2.buf.len > 0)
{
if (!link_socket_verify_incoming_addr (&c->c2.buf, lsi, &c->c2.from))
link_socket_bad_incoming_addr (&c->c2.buf, lsi, &c->c2.from);
#ifdef ENABLE_CRYPTO
#ifdef ENABLE_SSL
if (c->c2.tls_multi)
{
/*
* If tls_pre_decrypt returns true, it means the incoming
* packet was a good TLS control channel packet. If so, TLS code
* will deal with the packet and set buf.len to 0 so downstream
* stages ignore it.
*
* If the packet is a data channel packet, tls_pre_decrypt
* will load crypto_options with the correct encryption key
* and return false.
*/
if (tls_pre_decrypt (c->c2.tls_multi, &c->c2.from, &c->c2.buf, &c->c2.crypto_options))
{
interval_action (&c->c2.tmp_int);
/* reset packet received timer if TLS packet */
if (c->options.ping_rec_timeout)
event_timeout_reset (&c->c2.ping_rec_interval);
}
}
#if P2MP_SERVER
/*
* Drop non-TLS packet if client-connect script/plugin has not
* yet succeeded.
*/
if (c->c2.context_auth != CAS_SUCCEEDED)
c->c2.buf.len = 0;
#endif
#endif /* ENABLE_SSL */
/* authenticate and decrypt the incoming packet */
decrypt_status = openvpn_decrypt (&c->c2.buf, c->c2.buffers->decrypt_buf, &c->c2.crypto_options, &c->c2.frame);
if (!decrypt_status && link_socket_connection_oriented (c->c2.link_socket))
{
/* decryption errors are fatal in TCP mode */
register_signal (c, SIGUSR1, "decryption-error"); /* SOFT-SIGUSR1 -- decryption error in TCP mode */
msg (D_STREAM_ERRORS, "Fatal decryption error (process_incoming_link), restarting");
goto done;
}
#endif /* ENABLE_CRYPTO */
#ifdef ENABLE_FRAGMENT
if (c->c2.fragment)
fragment_incoming (c->c2.fragment, &c->c2.buf, &c->c2.frame_fragment);
#endif
#ifdef ENABLE_LZO
/* decompress the incoming packet */
if (lzo_defined (&c->c2.lzo_compwork))
lzo_decompress (&c->c2.buf, c->c2.buffers->lzo_decompress_buf, &c->c2.lzo_compwork, &c->c2.frame);
#endif
#ifdef PACKET_TRUNCATION_CHECK
/* if (c->c2.buf.len > 1) --c->c2.buf.len; */
ipv4_packet_size_verify (BPTR (&c->c2.buf),
BLEN (&c->c2.buf),
TUNNEL_TYPE (c->c1.tuntap),
"POST_DECRYPT",
&c->c2.n_trunc_post_decrypt);
#endif
/*
* Set our "official" outgoing address, since
* if buf.len is non-zero, we know the packet
* authenticated. In TLS mode we do nothing
* because TLS mode takes care of source address
* authentication.
*
* Also, update the persisted version of our packet-id.
*/
if (!TLS_MODE (c))
link_socket_set_outgoing_addr (&c->c2.buf, lsi, &c->c2.from, NULL, c->c2.es);
/* reset packet received timer */
if (c->options.ping_rec_timeout && c->c2.buf.len > 0)
event_timeout_reset (&c->c2.ping_rec_interval);
/* increment authenticated receive byte count */
if (c->c2.buf.len > 0)
{
c->c2.link_read_bytes_auth += c->c2.buf.len;
c->c2.max_recv_size_local = max_int (c->c2.original_recv_size, c->c2.max_recv_size_local);
}
/* Did we just receive an openvpn ping packet? */
if (is_ping_msg (&c->c2.buf))
{
dmsg (D_PING, "RECEIVED PING PACKET");
c->c2.buf.len = 0; /* drop packet */
}
#ifdef ENABLE_OCC
/* Did we just receive an OCC packet? */
if (is_occ_msg (&c->c2.buf))
process_received_occ_msg (c);
#endif
buffer_turnover (orig_buf, &c->c2.to_tun, &c->c2.buf, &c->c2.buffers->read_link_buf);
/* to_tun defined + unopened tuntap can cause deadlock */
if (!tuntap_defined (c->c1.tuntap))
c->c2.to_tun.len = 0;
}
else
{
buf_reset (&c->c2.to_tun);
}
done:
perf_pop ();
gc_free (&gc);
}
void
process_outgoing_link (struct context *c)
{
struct gc_arena gc = gc_new ();
perf_push (PERF_PROC_OUT_LINK);
if (c->c2.to_link.len > 0 && c->c2.to_link.len <= EXPANDED_SIZE (&c->c2.frame))
{
/*
* Setup for call to send/sendto which will send
* packet to remote over the TCP/UDP port.
*/
int size = 0;
ASSERT (link_socket_actual_defined (c->c2.to_link_addr));
#ifdef ENABLE_DEBUG
/* In gremlin-test mode, we may choose to drop this packet */
if (!c->options.gremlin || ask_gremlin (c->options.gremlin))
#endif
{
/*
* Let the traffic shaper know how many bytes
* we wrote.
*/
#ifdef ENABLE_FEATURE_SHAPER
if (c->options.shaper)
shaper_wrote_bytes (&c->c2.shaper, BLEN (&c->c2.to_link)
+ datagram_overhead (c->options.ce.proto));
#endif
/*
* Let the pinger know that we sent a packet.
*/
if (c->options.ping_send_timeout)
event_timeout_reset (&c->c2.ping_send_interval);
#if PASSTOS_CAPABILITY
/* Set TOS */
link_socket_set_tos (c->c2.link_socket);
#endif
/* Log packet send */
#ifdef LOG_RW
if (c->c2.log_rw)
fprintf (stderr, "W");
#endif
msg (D_LINK_RW, "%s WRITE [%d] to %s: %s",
proto2ascii (c->c2.link_socket->info.proto, true),
BLEN (&c->c2.to_link),
print_link_socket_actual (c->c2.to_link_addr, &gc),
PROTO_DUMP (&c->c2.to_link, &gc));
/* Packet send complexified by possible Socks5 usage */
{
struct link_socket_actual *to_addr = c->c2.to_link_addr;
#ifdef ENABLE_SOCKS
int size_delta = 0;
#endif
#ifdef ENABLE_SOCKS
/* If Socks5 over UDP, prepend header */
socks_preprocess_outgoing_link (c, &to_addr, &size_delta);
#endif
/* Send packet */
size = link_socket_write (c->c2.link_socket,
&c->c2.to_link,
to_addr);
#ifdef ENABLE_SOCKS
/* Undo effect of prepend */
link_socket_write_post_size_adjust (&size, size_delta, &c->c2.to_link);
#endif
}
if (size > 0)
{
c->c2.max_send_size_local = max_int (size, c->c2.max_send_size_local);
c->c2.link_write_bytes += size;
link_write_bytes_global += size;
#ifdef ENABLE_MEMSTATS
if (mmap_stats)
mmap_stats->link_write_bytes = link_write_bytes_global;
#endif
#ifdef ENABLE_MANAGEMENT
if (management)
{
management_bytes_out (management, size);
#ifdef MANAGEMENT_DEF_AUTH
management_bytes_server (management, &c->c2.link_read_bytes, &c->c2.link_write_bytes, &c->c2.mda_context);
#endif
}
#endif
}
}
/* Check return status */
check_status (size, "write", c->c2.link_socket, NULL);
if (size > 0)
{
/* Did we write a different size packet than we intended? */
if (size != BLEN (&c->c2.to_link))
msg (D_LINK_ERRORS,
"TCP/UDP packet was truncated/expanded on write to %s (tried=%d,actual=%d)",
print_link_socket_actual (c->c2.to_link_addr, &gc),
BLEN (&c->c2.to_link),
size);
}
/* if not a ping/control message, indicate activity regarding --inactive parameter */
if (c->c2.buf.len > 0 )
register_activity (c, size);
}
else
{
if (c->c2.to_link.len > 0)
msg (D_LINK_ERRORS, "TCP/UDP packet too large on write to %s (tried=%d,max=%d)",
print_link_socket_actual (c->c2.to_link_addr, &gc),
c->c2.to_link.len,
EXPANDED_SIZE (&c->c2.frame));
}
buf_reset (&c->c2.to_link);
perf_pop ();
gc_free (&gc);
}
bool
process_incoming_link_part1 (struct context *c, struct link_socket_info *lsi, bool floated)
{
struct gc_arena gc = gc_new ();
bool decrypt_status = false;
if (c->c2.buf.len > 0)
{
c->c2.link_read_bytes += c->c2.buf.len;
link_read_bytes_global += c->c2.buf.len;
#ifdef ENABLE_MEMSTATS
if (mmap_stats)
mmap_stats->link_read_bytes = link_read_bytes_global;
#endif
c->c2.original_recv_size = c->c2.buf.len;
#ifdef ENABLE_MANAGEMENT
if (management)
{
management_bytes_in (management, c->c2.buf.len);
#ifdef MANAGEMENT_DEF_AUTH
management_bytes_server (management, &c->c2.link_read_bytes, &c->c2.link_write_bytes, &c->c2.mda_context);
#endif
}
#endif
}
else
c->c2.original_recv_size = 0;
#ifdef ENABLE_DEBUG
/* take action to corrupt packet if we are in gremlin test mode */
if (c->options.gremlin) {
if (!ask_gremlin (c->options.gremlin))
c->c2.buf.len = 0;
corrupt_gremlin (&c->c2.buf, c->options.gremlin);
}
#endif
/* log incoming packet */
#ifdef LOG_RW
if (c->c2.log_rw && c->c2.buf.len > 0)
fprintf (stderr, "R");
#endif
msg (D_LINK_RW, "%s READ [%d] from %s: %s",
proto2ascii (lsi->proto, lsi->af, true),
BLEN (&c->c2.buf),
print_link_socket_actual (&c->c2.from, &gc),
PROTO_DUMP (&c->c2.buf, &gc));
/*
* Good, non-zero length packet received.
* Commence multi-stage processing of packet,
* such as authenticate, decrypt, decompress.
* If any stage fails, it sets buf.len to 0 or -1,
* telling downstream stages to ignore the packet.
*/
if (c->c2.buf.len > 0)
{
if (!link_socket_verify_incoming_addr (&c->c2.buf, lsi, &c->c2.from))
link_socket_bad_incoming_addr (&c->c2.buf, lsi, &c->c2.from);
#ifdef ENABLE_CRYPTO
#ifdef ENABLE_SSL
if (c->c2.tls_multi)
{
/*
* If tls_pre_decrypt returns true, it means the incoming
* packet was a good TLS control channel packet. If so, TLS code
* will deal with the packet and set buf.len to 0 so downstream
* stages ignore it.
*
* If the packet is a data channel packet, tls_pre_decrypt
* will load crypto_options with the correct encryption key
* and return false.
*/
if (tls_pre_decrypt (c->c2.tls_multi, &c->c2.from, &c->c2.buf, &c->c2.crypto_options, floated))
{
interval_action (&c->c2.tmp_int);
/* reset packet received timer if TLS packet */
if (c->options.ping_rec_timeout)
event_timeout_reset (&c->c2.ping_rec_interval);
}
}
#if P2MP_SERVER
/*
* Drop non-TLS packet if client-connect script/plugin has not
* yet succeeded.
*/
if (c->c2.context_auth != CAS_SUCCEEDED)
c->c2.buf.len = 0;
#endif
#endif /* ENABLE_SSL */
/* authenticate and decrypt the incoming packet */
decrypt_status = openvpn_decrypt (&c->c2.buf, c->c2.buffers->decrypt_buf, &c->c2.crypto_options, &c->c2.frame);
if (!decrypt_status && link_socket_connection_oriented (c->c2.link_socket))
{
/* decryption errors are fatal in TCP mode */
register_signal (c, SIGUSR1, "decryption-error"); /* SOFT-SIGUSR1 -- decryption error in TCP mode */
msg (D_STREAM_ERRORS, "Fatal decryption error (process_incoming_link), restarting");
}
#else /* ENABLE_CRYPTO */
decrypt_status = true;
#endif /* ENABLE_CRYPTO */
}
else
{
buf_reset (&c->c2.to_tun);
}
gc_free (&gc);
return decrypt_status;
}
/**
* Drops UDP packets which OS decided to route via tun.
*
* On Windows and OS X when netwotk adapter is disabled or
* disconnected, platform starts to use tun as external interface.
* When packet is sent to tun, it comes to openvpn, encapsulated
* and sent to routing table, which sends it again to tun.
*/
static void
drop_if_recursive_routing (struct context *c, struct buffer *buf)
{
bool drop = false;
struct openvpn_sockaddr tun_sa;
int ip_hdr_offset = 0;
if (c->c2.to_link_addr == NULL) /* no remote addr known */
return;
tun_sa = c->c2.to_link_addr->dest;
int proto_ver = get_tun_ip_ver (TUNNEL_TYPE (c->c1.tuntap), &c->c2.buf, &ip_hdr_offset);
if (proto_ver == 4)
{
const struct openvpn_iphdr *pip;
/* make sure we got whole IP header */
if (BLEN (buf) < ((int) sizeof (struct openvpn_iphdr) + ip_hdr_offset))
return;
/* skip ipv4 packets for ipv6 tun */
if (tun_sa.addr.sa.sa_family != AF_INET)
return;
pip = (struct openvpn_iphdr *) (BPTR (buf) + ip_hdr_offset);
/* drop packets with same dest addr as gateway */
if (tun_sa.addr.in4.sin_addr.s_addr == pip->daddr)
drop = true;
}
else if (proto_ver == 6)
{
const struct openvpn_ipv6hdr *pip6;
/* make sure we got whole IPv6 header */
if (BLEN (buf) < ((int) sizeof (struct openvpn_ipv6hdr) + ip_hdr_offset))
return;
/* skip ipv6 packets for ipv4 tun */
if (tun_sa.addr.sa.sa_family != AF_INET6)
return;
/* drop packets with same dest addr as gateway */
pip6 = (struct openvpn_ipv6hdr *) (BPTR (buf) + ip_hdr_offset);
if (IN6_ARE_ADDR_EQUAL(&tun_sa.addr.in6.sin6_addr, &pip6->daddr))
drop = true;
}
if (drop)
{
struct gc_arena gc = gc_new ();
c->c2.buf.len = 0;
msg(D_LOW, "Recursive routing detected, drop tun packet to %s",
print_link_socket_actual(c->c2.to_link_addr, &gc));
gc_free (&gc);
}
}