Move crypto_options into key_state and stop using context in SSL-mode.

Moving crypto_options into key_state enables us to stop using the global
context for each packet encrypt/decrypt operation. Decoupling the crypto
from the global context removes the need to copy the relevant parts of
crypto_options for each processed packet, but instead enables us to just
pass along a pointer to the related crypto_options.

This paves the way for an efficient GCM cipher mode implementation, but is
probably fruitful too for threading and/or cipher negotiation.

Signed-off-by: Steffan Karger <steffan@karger.me>
Acked-by: Arne Schwabe <arne@rfc2549.org>
Message-Id: <1454874438-5081-4-git-send-email-steffan@karger.me>
URL: http://article.gmane.org/gmane.network.openvpn.devel/11075
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c
index 36a99e6f7df37c9ec3d658cb1db285766a8f1468..75cd21decef7f3defb08140ac99c567febf17119 100644 (file)
--- a/src/openvpn/forward.c
+++ b/src/openvpn/forward.c
@@ -432,6 +432,7 @@ encrypt_sign (struct context *c, bool comp_frag)
 {
   struct context_buffers *b = c->c2.buffers;
   const uint8_t *orig_buf = c->c2.buf.data;
+  struct crypto_options *co = NULL;
 
 #if P2MP_SERVER
   /*
@@ -462,14 +463,18 @@ encrypt_sign (struct context *c, bool comp_frag)
    */
   if (c->c2.tls_multi)
     {
-      tls_pre_encrypt (c->c2.tls_multi, &c->c2.buf, &c->c2.crypto_options);
+      tls_pre_encrypt (c->c2.tls_multi, &c->c2.buf, &co);
+    }
+  else
+    {
+      co = &c->c2.crypto_options;
     }
 
   /*
    * Encrypt the packet and write an optional
    * HMAC signature.
    */
-  openvpn_encrypt (&c->c2.buf, b->encrypt_buf, &c->c2.crypto_options, &c->c2.frame);
+  openvpn_encrypt (&c->c2.buf, b->encrypt_buf, co, &c->c2.frame);
 #endif
   /*
    * Get the address we will be sending the packet to.
@@ -774,6 +779,7 @@ process_incoming_link_part1 (struct context *c, struct link_socket_info *lsi, bo
    */
   if (c->c2.buf.len > 0)
     {
+      struct crypto_options *co = NULL;
       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);
 
@@ -790,7 +796,7 @@ process_incoming_link_part1 (struct context *c, struct link_socket_info *lsi, bo
           * 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))
+         if (tls_pre_decrypt (c->c2.tls_multi, &c->c2.from, &c->c2.buf, &co, floated))
            {
              interval_action (&c->c2.tmp_int);
 
@@ -799,6 +805,10 @@ process_incoming_link_part1 (struct context *c, struct link_socket_info *lsi, bo
                event_timeout_reset (&c->c2.ping_rec_interval);
            }
        }
+      else
+       {
+         co = &c->c2.crypto_options;
+       }
 #if P2MP_SERVER
       /*
        * Drop non-TLS packet if client-connect script/plugin has not
@@ -809,7 +819,7 @@ process_incoming_link_part1 (struct context *c, struct link_socket_info *lsi, bo
 #endif
 
       /* 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);
+      decrypt_status = openvpn_decrypt (&c->c2.buf, c->c2.buffers->decrypt_buf, co, &c->c2.frame);
 
       if (!decrypt_status && link_socket_connection_oriented (c->c2.link_socket))
        {

diff --git a/src/openvpn/init.c b/src/openvpn/init.c
index 7e6e448101c6b1f7596653a80e74601113a53ce3..8fc5c5dfcb74780d23a971b3b34a5a22563e2fc3 100644 (file)
--- a/src/openvpn/init.c
+++ b/src/openvpn/init.c
@@ -2048,14 +2048,6 @@ init_crypto_pre (struct context *c, const unsigned int flags)
        packet_id_persist_load (&c->c1.pid_persist, c->options.packet_id_file);
     }
 
-  /* Initialize crypto options */
-
-  if (c->options.use_iv)
-    c->c2.crypto_options.flags |= CO_USE_IV;
-
-  if (c->options.mute_replay_warnings)
-    c->c2.crypto_options.flags |= CO_MUTE_REPLAY_WARNINGS;
-
 #ifdef ENABLE_PREDICTION_RESISTANCE
   if (c->options.use_prediction_resistance)
     rand_ctx_enable_prediction_resistance();
@@ -2074,6 +2066,13 @@ do_init_crypto_static (struct context *c, const unsigned int flags)
 
   init_crypto_pre (c, flags);
 
+  /* Initialize flags */
+  if (c->options.use_iv)
+    c->c2.crypto_options.flags |= CO_USE_IV;
+
+  if (c->options.mute_replay_warnings)
+    c->c2.crypto_options.flags |= CO_MUTE_REPLAY_WARNINGS;
+
   /* Initialize packet ID tracking */
   if (options->replay)
     {
@@ -2277,6 +2276,12 @@ do_init_crypto_tls (struct context *c, const unsigned int flags)
   /* Set all command-line TLS-related options */
   CLEAR (to);
 
+  if (options->use_iv)
+    to.crypto_flags |= CO_USE_IV;
+
+  if (options->mute_replay_warnings)
+    to.crypto_flags |= CO_MUTE_REPLAY_WARNINGS;
+
   to.crypto_flags_and = ~(CO_PACKET_ID_LONG_FORM);
   if (packet_id_long_form)
     to.crypto_flags_or = CO_PACKET_ID_LONG_FORM;

diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index d39f131dba86746831d69aa32d0c8206525d9309..6aa928449004b800d3cb7c4a381da179e20565ab 100644 (file)
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -786,6 +786,13 @@ key_state_init (struct tls_session *session, struct key_state *ks)
                  session->opt->replay_time,
                  "SSL", ks->key_id);
 
+  ks->crypto_options.key_ctx_bi = &ks->key;
+  ks->crypto_options.packet_id = session->opt->replay ? &ks->packet_id : NULL;
+  ks->crypto_options.pid_persist = NULL;
+  ks->crypto_options.flags = session->opt->crypto_flags;
+  ks->crypto_options.flags &= session->opt->crypto_flags_and;
+  ks->crypto_options.flags |= session->opt->crypto_flags_or;
+
 #ifdef MANAGEMENT_DEF_AUTH
   ks->mda_key_id = session->opt->mda_context->mda_key_id_counter++;
 #endif
@@ -1700,6 +1707,8 @@ key_state_soft_reset (struct tls_session *session)
   ks->must_die = now + session->opt->transition_window; /* remaining lifetime of old key */
   key_state_free (ks_lame, false);
   *ks_lame = *ks;
+  ks_lame->crypto_options.key_ctx_bi = &ks_lame->key;
+  ks_lame->crypto_options.packet_id = &ks_lame->packet_id;
 
   key_state_init (session, ks);
   ks->session_id_remote = ks_lame->session_id_remote;
@@ -2808,7 +2817,7 @@ bool
 tls_pre_decrypt (struct tls_multi *multi,
                 const struct link_socket_actual *from,
                 struct buffer *buf,
-                struct crypto_options *opt,
+                struct crypto_options **opt,
                 bool floated)
 {
   struct gc_arena gc = gc_new ();
@@ -2856,12 +2865,7 @@ tls_pre_decrypt (struct tls_multi *multi,
                  && (floated || 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;
-
+                 *opt = &ks->crypto_options;
                  ASSERT (buf_advance (buf, 1));
                  if (op == P_DATA_V2)
                    {
@@ -3251,10 +3255,7 @@ tls_pre_decrypt (struct tls_multi *multi,
 
  done:
   buf->len = 0;
-  opt->key_ctx_bi = NULL;
-  opt->packet_id = NULL;
-  opt->pid_persist = NULL;
-  opt->flags &= multi->opt.crypto_flags_and;
+  *opt = NULL;
   gc_free (&gc);
   return ret;
 
@@ -3380,7 +3381,7 @@ tls_pre_decrypt_lite (const struct tls_auth_standalone *tas,
 /* 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)
+                struct buffer *buf, struct crypto_options **opt)
 {
   multi->save_ks = NULL;
   if (buf->len > 0)
@@ -3409,11 +3410,7 @@ tls_pre_encrypt (struct tls_multi *multi,
 
       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;
+         *opt = &ks_select->crypto_options;
          multi->save_ks = ks_select;
          dmsg (D_TLS_KEYSELECT, "TLS: tls_pre_encrypt: key_id=%d", ks_select->key_id);
          return;
@@ -3428,10 +3425,7 @@ tls_pre_encrypt (struct tls_multi *multi,
     }
 
   buf->len = 0;
-  opt->key_ctx_bi = NULL;
-  opt->packet_id = NULL;
-  opt->pid_persist = NULL;
-  opt->flags &= multi->opt.crypto_flags_and;
+  *opt = NULL;
 }
 
 /* Prepend the appropriate opcode to encrypted buffer prior to TCP/UDP send */

diff --git a/src/openvpn/ssl.h b/src/openvpn/ssl.h
index 797c3e5d540b702a5cd5b33b8f5a290e2086d95a..e9d0f28bc8b504a936acc0bd11e195b08c235c5c 100644 (file)
--- a/src/openvpn/ssl.h
+++ b/src/openvpn/ssl.h
@@ -293,9 +293,8 @@ int tls_multi_process (struct tls_multi *multi,
  *     of this packet.
  * @param from - The source address of the packet.
  * @param buf - A buffer structure containing the incoming packet.
- * @param opt - A crypto options structure that will be loaded with the
- *     appropriate security parameters to handle the packet if it is a
- *     data channel packet.
+ * @param opt - Returns a crypto options structure with the appropriate security
+ *     parameters to handle the packet if it is a data channel packet.
  *
  * @return
  * @li True if the packet is a control channel packet that has been
@@ -306,7 +305,7 @@ int tls_multi_process (struct tls_multi *multi,
 bool tls_pre_decrypt (struct tls_multi *multi,
                      const struct link_socket_actual *from,
                      struct buffer *buf,
-                     struct crypto_options *opt,
+                     struct crypto_options **opt,
                      bool floated);
 
 
@@ -356,15 +355,15 @@ bool tls_pre_decrypt_lite (const struct tls_auth_standalone *tas,
  * @ingroup data_crypto
  *
  * If no appropriate security parameters can be found, or if some other
- * error occurs, then the buffer is set to empty.
+ * error occurs, then the buffer is set to empty, and the parameters to a NULL
+ * pointer.
  *
  * @param multi - The TLS state for this packet's destination VPN tunnel.
  * @param buf - The buffer containing the outgoing packet.
- * @param opt - The crypto options structure into which the appropriate
- *     security parameters should be loaded.
+ * @param opt - Returns a crypto options structure with the security parameters.
  */
 void tls_pre_encrypt (struct tls_multi *multi,
-                     struct buffer *buf, struct crypto_options *opt);
+                     struct buffer *buf, struct crypto_options **opt);
 
 
 /**

diff --git a/src/openvpn/ssl_common.h b/src/openvpn/ssl_common.h
index e2b0ebf0f74307b5fdc1eabb1ad2a5c55966b111..00d2ce87bff1d6e3e1d26cc752fcb9ba34074518 100644 (file)
--- a/src/openvpn/ssl_common.h
+++ b/src/openvpn/ssl_common.h
@@ -162,6 +162,7 @@ struct key_state
   struct link_socket_actual remote_addr; /* peer's IP addr */
   struct packet_id packet_id;         /* for data channel, to prevent replay attacks */
 
+  struct crypto_options crypto_options;/* data channel crypto options */
   struct key_ctx_bi key;              /* data channel keys for encrypt/decrypt/hmac */
 
   struct key_source2 *key_src;         /* source entropy for key expansion */
@@ -259,6 +260,7 @@ struct tls_options
   bool pass_config_info;
 
   /* struct crypto_option flags */
+  unsigned int crypto_flags;
   unsigned int crypto_flags_and;
   unsigned int crypto_flags_or;