tls: make tls engines pluggable

- add infra for pluggable tls "engines"
- makes mbedtls specific code a plugin

Change-Id: I2c5b099e2b69d2be0038e3ef02b208ff907727e7
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 548 insertions, 0 deletions

diff --git a/src/plugins/tlsmbedtls/tls_mbedtls.c b/src/plugins/tlsmbedtls/tls_mbedtls.c
new file mode 100644
index 00000000000..1bae1f726f8
--- /dev/null
+++ b/src/plugins/tlsmbedtls/tls_mbedtls.c
@@ -0,0 +1,548 @@
+/*
+ * Copyright (c) 2018 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <mbedtls/ssl.h>
+#include <mbedtls/certs.h>
+#include <mbedtls/entropy.h>
+#include <mbedtls/ctr_drbg.h>
+#include <mbedtls/timing.h>
+#include <mbedtls/debug.h>
+#include <vnet/plugin/plugin.h>
+#include <vpp/app/version.h>
+#include <vnet/tls/tls.h>
+
+#define TLS_USE_OUR_MEM_FUNCS	0
+
+typedef struct tls_ctx_mbedtls_
+{
+  tls_ctx_t ctx;			/**< First */
+  mbedtls_ssl_context ssl;
+  mbedtls_ssl_config conf;
+  mbedtls_x509_crt srvcert;
+  mbedtls_pk_context pkey;
+} mbedtls_ctx_t;
+
+typedef struct mbedtls_main_
+{
+  mbedtls_ctx_t ***ctx_pool;
+  mbedtls_ctr_drbg_context *ctr_drbgs;
+  mbedtls_entropy_context *entropy_pools;
+  mbedtls_x509_crt cacert;
+} mbedtls_main_t;
+
+static mbedtls_main_t mbedtls_main;
+
+#if TLS_USE_OUR_MEM_FUNCS
+#include <mbedtls/platform.h>
+
+void *
+mbedtls_calloc_fn (size_t n, size_t size)
+{
+  void *ptr;
+  ptr = clib_mem_alloc (n * size);
+  memset (ptr, 0, sizeof (*ptr));
+  return ptr;
+}
+
+void
+mbedtls_free_fn (void *ptr)
+{
+  if (ptr)
+    clib_mem_free (ptr);
+}
+#endif
+
+u32
+mbedtls_ctx_alloc (void)
+{
+  u8 thread_index = vlib_get_thread_index ();
+  mbedtls_main_t *tm = &mbedtls_main;
+  mbedtls_ctx_t **ctx;
+
+  pool_get (tm->ctx_pool[thread_index], ctx);
+  if (!(*ctx))
+    *ctx = clib_mem_alloc (sizeof (mbedtls_ctx_t));
+
+  memset (*ctx, 0, sizeof (mbedtls_ctx_t));
+  (*ctx)->ctx.c_thread_index = thread_index;
+  return ctx - tm->ctx_pool[thread_index];
+}
+
+void
+mbedtls_ctx_free (tls_ctx_t * ctx)
+{
+  mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
+
+  if (mc->ssl.state == MBEDTLS_SSL_HANDSHAKE_OVER && !ctx->is_passive_close)
+    mbedtls_ssl_close_notify (&mc->ssl);
+  if (mc->ssl.conf->endpoint == MBEDTLS_SSL_IS_SERVER)
+    {
+      mbedtls_x509_crt_free (&mc->srvcert);
+      mbedtls_pk_free (&mc->pkey);
+    }
+  mbedtls_ssl_free (&mc->ssl);
+  mbedtls_ssl_config_free (&mc->conf);
+
+  pool_put_index (mbedtls_main.ctx_pool[vlib_get_thread_index ()],
+		  ctx->tls_ctx_idx);
+}
+
+tls_ctx_t *
+mbedtls_ctx_get (u32 ctx_index)
+{
+  mbedtls_ctx_t **ctx;
+  ctx = pool_elt_at_index (mbedtls_main.ctx_pool[vlib_get_thread_index ()],
+			   ctx_index);
+  return &(*ctx)->ctx;
+}
+
+tls_ctx_t *
+mbedtls_ctx_get_w_thread (u32 ctx_index, u8 thread_index)
+{
+  mbedtls_ctx_t **ctx;
+  ctx = pool_elt_at_index (mbedtls_main.ctx_pool[thread_index], ctx_index);
+  return &(*ctx)->ctx;
+}
+
+static int
+tls_init_ctr_seed_drbgs (void)
+{
+  u32 thread_index = vlib_get_thread_index ();
+  mbedtls_main_t *tm = &mbedtls_main;
+  u8 *pers;
+  int rv;
+  pers = format (0, "vpp thread %u", thread_index);
+
+  mbedtls_entropy_init (&tm->entropy_pools[thread_index]);
+  mbedtls_ctr_drbg_init (&mbedtls_main.ctr_drbgs[thread_index]);
+  if ((rv = mbedtls_ctr_drbg_seed (&tm->ctr_drbgs[thread_index],
+				   mbedtls_entropy_func,
+				   &tm->entropy_pools[thread_index],
+				   (const unsigned char *) pers,
+				   vec_len (pers))) != 0)
+    {
+      vec_free (pers);
+      TLS_DBG (1, " failed\n  ! mbedtls_ctr_drbg_seed returned %d\n", rv);
+      return -1;
+    }
+  vec_free (pers);
+  return 0;
+}
+
+mbedtls_ctr_drbg_context *
+tls_get_ctr_drbg ()
+{
+  u8 thread_index = vlib_get_thread_index ();
+  if (PREDICT_FALSE (!mbedtls_main.ctr_drbgs[thread_index].f_entropy))
+    tls_init_ctr_seed_drbgs ();
+  return &mbedtls_main.ctr_drbgs[thread_index];
+}
+
+static int
+tls_net_send (void *ctx_indexp, const unsigned char *buf, size_t len)
+{
+  stream_session_t *tls_session;
+  uword ctx_index;
+  tls_ctx_t *ctx;
+  int rv;
+
+  ctx_index = pointer_to_uword (ctx_indexp);
+  ctx = mbedtls_ctx_get (ctx_index);
+  tls_session = session_get_from_handle (ctx->tls_session_handle);
+  rv = svm_fifo_enqueue_nowait (tls_session->server_tx_fifo, len, buf);
+  if (rv < 0)
+    return MBEDTLS_ERR_SSL_WANT_WRITE;
+  tls_add_vpp_q_evt (tls_session->server_tx_fifo, FIFO_EVENT_APP_TX);
+  return rv;
+}
+
+static int
+tls_net_recv (void *ctx_indexp, unsigned char *buf, size_t len)
+{
+  stream_session_t *tls_session;
+  uword ctx_index;
+  tls_ctx_t *ctx;
+  int rv;
+
+  ctx_index = pointer_to_uword (ctx_indexp);
+  ctx = mbedtls_ctx_get (ctx_index);
+  tls_session = session_get_from_handle (ctx->tls_session_handle);
+  rv = svm_fifo_dequeue_nowait (tls_session->server_rx_fifo, len, buf);
+  return (rv < 0) ? 0 : rv;
+}
+
+static void
+mbedtls_debug (void *ctx, int level, const char *file, int line,
+	       const char *str)
+{
+  ((void) level);
+  fprintf ((FILE *) ctx, "%s:%04d: %s", file, line, str);
+  fflush ((FILE *) ctx);
+}
+
+static int
+mbedtls_ctx_init_client (tls_ctx_t * ctx)
+{
+  mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
+  mbedtls_main_t *mm = &mbedtls_main;
+  void *ctx_ptr;
+  int rv;
+
+  /*
+   * 1. Setup SSL
+   */
+  mbedtls_ssl_init (&mc->ssl);
+  mbedtls_ssl_config_init (&mc->conf);
+  if ((rv = mbedtls_ssl_config_defaults (&mc->conf, MBEDTLS_SSL_IS_CLIENT,
+					 MBEDTLS_SSL_TRANSPORT_STREAM,
+					 MBEDTLS_SSL_PRESET_DEFAULT)) != 0)
+    {
+      TLS_DBG (1, "failed\n  ! mbedtls_ssl_config_defaults returned %d\n\n",
+	       rv);
+      return -1;
+    }
+
+  mbedtls_ssl_conf_authmode (&mc->conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
+  mbedtls_ssl_conf_ca_chain (&mc->conf, &mm->cacert, NULL);
+  mbedtls_ssl_conf_rng (&mc->conf, mbedtls_ctr_drbg_random,
+			tls_get_ctr_drbg ());
+  mbedtls_ssl_conf_dbg (&mc->conf, mbedtls_debug, stdout);
+
+  if ((rv = mbedtls_ssl_setup (&mc->ssl, &mc->conf)) != 0)
+    {
+      TLS_DBG (1, "failed\n  ! mbedtls_ssl_setup returned %d\n", rv);
+      return -1;
+    }
+
+  if ((rv = mbedtls_ssl_set_hostname (&mc->ssl,
+				      (const char *) ctx->srv_hostname)) != 0)
+    {
+      TLS_DBG (1, "failed\n  ! mbedtls_ssl_set_hostname returned %d\n", rv);
+      return -1;
+    }
+
+  ctx_ptr = uword_to_pointer (ctx->tls_ctx_idx, void *);
+  mbedtls_ssl_set_bio (&mc->ssl, ctx_ptr, tls_net_send, tls_net_recv, NULL);
+  mbedtls_debug_set_threshold (TLS_DEBUG_LEVEL_CLIENT);
+
+  /*
+   * 2. Do the first 2 steps in the handshake.
+   */
+  TLS_DBG (1, "Initiating handshake for [%u]%u", ctx->c_thread_index,
+	   ctx->tls_ctx_idx);
+  while (mc->ssl.state != MBEDTLS_SSL_HANDSHAKE_OVER)
+    {
+      rv = mbedtls_ssl_handshake_step (&mc->ssl);
+      if (rv != 0)
+	break;
+    }
+  TLS_DBG (2, "tls state for [%u]%u is %u", ctx->c_thread_index,
+	   ctx->tls_ctx_idx, mc->ssl.state);
+  return 0;
+}
+
+static int
+mbedtls_ctx_init_server (tls_ctx_t * ctx)
+{
+  mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
+  mbedtls_main_t *mm = &mbedtls_main;
+  application_t *app;
+  void *ctx_ptr;
+  int rv;
+
+  mbedtls_ssl_init (&mc->ssl);
+  mbedtls_ssl_config_init (&mc->conf);
+  mbedtls_x509_crt_init (&mc->srvcert);
+  mbedtls_pk_init (&mc->pkey);
+
+  /*
+   * 1. Cert
+   */
+  app = application_get (ctx->parent_app_index);
+  if (!app->tls_cert || !app->tls_key)
+    {
+      TLS_DBG (1, " failed\n  ! tls cert and/or key not configured %d",
+	       ctx->parent_app_index);
+      return -1;
+    }
+
+  rv = mbedtls_x509_crt_parse (&mc->srvcert,
+			       (const unsigned char *) app->tls_cert,
+			       vec_len (app->tls_cert));
+  if (rv != 0)
+    {
+      TLS_DBG (1, " failed\n  !  mbedtls_x509_crt_parse returned %d", rv);
+      goto exit;
+    }
+
+  rv = mbedtls_pk_parse_key (&mc->pkey,
+			     (const unsigned char *) app->tls_key,
+			     vec_len (app->tls_key), NULL, 0);
+  if (rv != 0)
+    {
+      TLS_DBG (1, " failed\n  !  mbedtls_pk_parse_key returned %d", rv);
+      goto exit;
+    }
+
+  /*
+   * 2. SSL context config
+   */
+  if ((rv = mbedtls_ssl_config_defaults (&mc->conf, MBEDTLS_SSL_IS_SERVER,
+					 MBEDTLS_SSL_TRANSPORT_STREAM,
+					 MBEDTLS_SSL_PRESET_DEFAULT)) != 0)
+    {
+      TLS_DBG (1, " failed\n  ! mbedtls_ssl_config_defaults returned %d", rv);
+      goto exit;
+    }
+
+  mbedtls_ssl_conf_rng (&mc->conf, mbedtls_ctr_drbg_random,
+			tls_get_ctr_drbg ());
+  mbedtls_ssl_conf_dbg (&mc->conf, mbedtls_debug, stdout);
+
+  /* TODO CACHE
+     mbedtls_ssl_conf_session_cache( &ctx->conf, &cache,
+     mbedtls_ssl_cache_get,
+     mbedtls_ssl_cache_set );
+   */
+
+  mbedtls_ssl_conf_ca_chain (&mc->conf, &mm->cacert, NULL);
+  if ((rv = mbedtls_ssl_conf_own_cert (&mc->conf, &mc->srvcert, &mc->pkey))
+      != 0)
+    {
+      TLS_DBG (1, " failed\n  ! mbedtls_ssl_conf_own_cert returned %d", rv);
+      goto exit;
+    }
+
+  if ((rv = mbedtls_ssl_setup (&mc->ssl, &mc->conf)) != 0)
+    {
+      TLS_DBG (1, " failed\n  ! mbedtls_ssl_setup returned %d", rv);
+      goto exit;
+    }
+
+  mbedtls_ssl_session_reset (&mc->ssl);
+  ctx_ptr = uword_to_pointer (ctx->tls_ctx_idx, void *);
+  mbedtls_ssl_set_bio (&mc->ssl, ctx_ptr, tls_net_send, tls_net_recv, NULL);
+  mbedtls_debug_set_threshold (TLS_DEBUG_LEVEL_SERVER);
+
+  /*
+   * 3. Start handshake state machine
+   */
+  TLS_DBG (1, "Initiating handshake for [%u]%u", ctx->c_thread_index,
+	   ctx->tls_ctx_idx);
+  while (mc->ssl.state != MBEDTLS_SSL_HANDSHAKE_OVER)
+    {
+      rv = mbedtls_ssl_handshake_step (&mc->ssl);
+      if (rv != 0)
+	break;
+    }
+
+  TLS_DBG (2, "tls state for [%u]%u is %u", ctx->c_thread_index,
+	   ctx->tls_ctx_idx, mc->ssl.state);
+  return 0;
+
+exit:
+  return -1;
+}
+
+static int
+mbedtls_handshake_rx (tls_ctx_t * ctx)
+{
+  mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
+  u32 flags;
+  int rv;
+  while (mc->ssl.state != MBEDTLS_SSL_HANDSHAKE_OVER)
+    {
+      rv = mbedtls_ssl_handshake_step (&mc->ssl);
+      if (rv != 0)
+	break;
+    }
+  TLS_DBG (2, "tls state for %u is %u", ctx->tls_ctx_idx, mc->ssl.state);
+
+  if (mc->ssl.state != MBEDTLS_SSL_HANDSHAKE_OVER)
+    return HANDSHAKE_NOT_OVER;
+
+  /*
+   * Handshake complete
+   */
+  if (mc->ssl.conf->endpoint == MBEDTLS_SSL_IS_CLIENT)
+    {
+      /*
+       * Verify server certificate
+       */
+      if ((flags = mbedtls_ssl_get_verify_result (&mc->ssl)) != 0)
+	{
+	  char buf[512];
+	  TLS_DBG (1, " failed\n");
+	  mbedtls_x509_crt_verify_info (buf, sizeof (buf), "  ! ", flags);
+	  TLS_DBG (1, "%s\n", buf);
+
+	  /*
+	   * Presence of hostname enforces strict certificate verification
+	   */
+	  if (ctx->srv_hostname)
+	    return CLIENT_HANDSHAKE_FAIL;
+	}
+      rv = CLIENT_HANDSHAKE_OK;
+    }
+  else
+    {
+      rv = SERVER_HANDSHAKE_OK;
+    }
+
+  TLS_DBG (1, "Handshake for %u complete. TLS cipher is %x",
+	   ctx->tls_ctx_idx, mc->ssl.session->ciphersuite);
+  return rv;
+}
+
+static int
+mbedtls_write (tls_ctx_t * ctx, u8 * buf, u32 len)
+{
+  mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
+  return mbedtls_ssl_write (&mc->ssl, buf, len);
+}
+
+static int
+mbedtls_read (tls_ctx_t * ctx, u8 * buf, u32 len)
+{
+  mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
+  return mbedtls_ssl_read (&mc->ssl, buf, len);
+}
+
+static u8
+mbedtls_handshake_is_over (tls_ctx_t * ctx)
+{
+  mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
+  return (mc->ssl.state == MBEDTLS_SSL_HANDSHAKE_OVER);
+}
+
+const static tls_engine_vft_t mbedtls_engine = {
+  .ctx_alloc = mbedtls_ctx_alloc,
+  .ctx_free = mbedtls_ctx_free,
+  .ctx_get = mbedtls_ctx_get,
+  .ctx_get_w_thread = mbedtls_ctx_get_w_thread,
+  .ctx_init_server = mbedtls_ctx_init_server,
+  .ctx_init_client = mbedtls_ctx_init_client,
+  .ctx_handshake_rx = mbedtls_handshake_rx,
+  .ctx_write = mbedtls_write,
+  .ctx_read = mbedtls_read,
+  .ctx_handshake_is_over = mbedtls_handshake_is_over,
+};
+
+int
+tls_init_mem (void)
+{
+#if TLS_USE_OUR_MEM_FUNCS
+  mbedtls_platform_set_calloc_free (mbedtls_calloc_fn, mbedtls_free_fn);
+#endif
+  return 0;
+}
+
+static int
+tls_init_ctr_drbgs_and_entropy (u32 num_threads)
+{
+  mbedtls_main_t *mm = &mbedtls_main;
+  int i;
+
+  vec_validate (mm->ctr_drbgs, num_threads - 1);
+  vec_validate (mm->entropy_pools, num_threads - 1);
+  for (i = 0; i < num_threads; i++)
+    mm->ctr_drbgs[i].f_entropy = 0;
+
+  return 0;
+}
+
+int
+tls_init_ca_chain (void)
+{
+  mbedtls_main_t *mm = &mbedtls_main;
+  tls_main_t *tm = vnet_tls_get_main ();
+  int rv;
+
+  if (access (tm->ca_cert_path, F_OK | R_OK) == -1)
+    {
+      clib_warning ("Could not initialize TLS CA certificates");
+      return -1;
+    }
+
+  mbedtls_x509_crt_init (&mm->cacert);
+  rv = mbedtls_x509_crt_parse_file (&mm->cacert, tm->ca_cert_path);
+  if (rv < 0)
+    {
+      clib_warning ("Couldn't parse system CA certificates: -0x%x", -rv);
+    }
+  if (tm->use_test_cert_in_ca)
+    {
+      rv = mbedtls_x509_crt_parse (&mm->cacert,
+				   (const unsigned char *) test_srv_crt_rsa,
+				   test_srv_crt_rsa_len);
+      if (rv < 0)
+	{
+	  clib_warning ("Couldn't parse test certificate: -0x%x", -rv);
+	  return -1;
+	}
+    }
+  return (rv < 0 ? -1 : 0);
+}
+
+static clib_error_t *
+tls_mbedtls_init (vlib_main_t * vm)
+{
+  vlib_thread_main_t *vtm = vlib_get_thread_main ();
+  mbedtls_main_t *mm = &mbedtls_main;
+  clib_error_t *error;
+  u32 num_threads;
+
+  num_threads = 1 /* main thread */  + vtm->n_threads;
+
+  if ((error = vlib_call_init_function (vm, tls_init)))
+    return error;
+
+  if (tls_init_ca_chain ())
+    {
+      clib_warning ("failed to initialize TLS CA chain");
+      return 0;
+    }
+  if (tls_init_mem ())
+    {
+      clib_warning ("failed to initialize mem");
+      return 0;
+    }
+  if (tls_init_ctr_drbgs_and_entropy (num_threads))
+    {
+      clib_warning ("failed to initialize entropy and random generators");
+      return 0;
+    }
+
+  vec_validate (mm->ctx_pool, num_threads - 1);
+  tls_register_engine (&mbedtls_engine, TLS_ENGINE_MBEDTLS);
+  return 0;
+}
+
+VLIB_INIT_FUNCTION (tls_mbedtls_init);
+
+/* *INDENT-OFF* */
+VLIB_PLUGIN_REGISTER () = {
+    .version = VPP_BUILD_VER,
+    .description = "mbedtls based TLS Engine",
+};
+/* *INDENT-ON* */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */